dmake: do not set MAKEFLAGS=k

[unleashed/tickless.git] / usr / src / lib / libproc / common / Psymtab.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2013 by Delphix. All rights reserved.
 * Copyright 2016 Joyent, Inc.
 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <ctype.h>
#include <fcntl.h>
#include <string.h>
#include <strings.h>
#include <memory.h>
#include <errno.h>
#include <dirent.h>
#include <signal.h>
#include <limits.h>
#include <libgen.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>

#include "libproc.h"
#include "Pcontrol.h"
#include "Putil.h"
#include "Psymtab_machelf.h"

static file_info_t *build_map_symtab(struct ps_prochandle *, map_info_t *);
static map_info_t *exec_map(struct ps_prochandle *);
static map_info_t *object_to_map(struct ps_prochandle *, Lmid_t, const char *);
static map_info_t *object_name_to_map(struct ps_prochandle *,
        Lmid_t, const char *);
static GElf_Sym *sym_by_name(sym_tbl_t *, const char *, GElf_Sym *, uint_t *);
static int read_ehdr32(struct ps_prochandle *, Elf32_Ehdr *, uint_t *,
    uintptr_t);
#ifdef _LP64
static int read_ehdr64(struct ps_prochandle *, Elf64_Ehdr *, uint_t *,
    uintptr_t);
#endif

#define DATA_TYPES      \
        ((1 << STT_OBJECT) | (1 << STT_FUNC) | \
        (1 << STT_COMMON) | (1 << STT_TLS))
#define IS_DATA_TYPE(tp)        (((1 << (tp)) & DATA_TYPES) != 0)

#define MA_RWX  (MA_READ | MA_WRITE | MA_EXEC)

typedef enum {
        PRO_NATURAL,
        PRO_BYADDR,
        PRO_BYNAME
} pr_order_t;

static int
addr_cmp(const void *aa, const void *bb)
{
        uintptr_t a = *((uintptr_t *)aa);
        uintptr_t b = *((uintptr_t *)bb);

        if (a > b)
                return (1);
        if (a < b)
                return (-1);
        return (0);
}

/*
 * This function creates a list of addresses for a load object's sections.
 * The list is in ascending address order and alternates start address
 * then end address for each section we're interested in. The function
 * returns a pointer to the list, which must be freed by the caller.
 */
static uintptr_t *
get_saddrs(struct ps_prochandle *P, uintptr_t ehdr_start, uint_t *n)
{
        uintptr_t a, addr, *addrs, last = 0;
        uint_t i, naddrs = 0, unordered = 0;

        if (P->status.pr_dmodel == PR_MODEL_ILP32) {
                Elf32_Ehdr ehdr;
                Elf32_Phdr phdr;
                uint_t phnum;

                if (read_ehdr32(P, &ehdr, &phnum, ehdr_start) != 0)
                        return (NULL);

                addrs = malloc(sizeof (uintptr_t) * phnum * 2);
                a = ehdr_start + ehdr.e_phoff;
                for (i = 0; i < phnum; i++, a += ehdr.e_phentsize) {
                        if (Pread(P, &phdr, sizeof (phdr), a) !=
                            sizeof (phdr)) {
                                free(addrs);
                                return (NULL);
                        }
                        if (phdr.p_type != PT_LOAD || phdr.p_memsz == 0)
                                continue;

                        addr = phdr.p_vaddr;
                        if (ehdr.e_type == ET_DYN)
                                addr += ehdr_start;
                        if (last > addr)
                                unordered = 1;
                        addrs[naddrs++] = addr;
                        addrs[naddrs++] = last = addr + phdr.p_memsz - 1;
                }
#ifdef _LP64
        } else {
                Elf64_Ehdr ehdr;
                Elf64_Phdr phdr;
                uint_t phnum;

                if (read_ehdr64(P, &ehdr, &phnum, ehdr_start) != 0)
                        return (NULL);

                addrs = malloc(sizeof (uintptr_t) * phnum * 2);
                a = ehdr_start + ehdr.e_phoff;
                for (i = 0; i < phnum; i++, a += ehdr.e_phentsize) {
                        if (Pread(P, &phdr, sizeof (phdr), a) !=
                            sizeof (phdr)) {
                                free(addrs);
                                return (NULL);
                        }
                        if (phdr.p_type != PT_LOAD || phdr.p_memsz == 0)
                                continue;

                        addr = phdr.p_vaddr;
                        if (ehdr.e_type == ET_DYN)
                                addr += ehdr_start;
                        if (last > addr)
                                unordered = 1;
                        addrs[naddrs++] = addr;
                        addrs[naddrs++] = last = addr + phdr.p_memsz - 1;
                }
#endif
        }

        if (unordered)
                qsort(addrs, naddrs, sizeof (uintptr_t), addr_cmp);

        *n = naddrs;
        return (addrs);
}

/*
 * Allocation function for a new file_info_t
 */
file_info_t *
file_info_new(struct ps_prochandle *P, map_info_t *mptr)
{
        file_info_t *fptr;
        map_info_t *mp;
        uintptr_t mstart, mend, sstart, send;
        uint_t i;

        if ((fptr = calloc(1, sizeof (file_info_t))) == NULL)
                return (NULL);

        list_link(fptr, &P->file_head);
        (void) strcpy(fptr->file_pname, mptr->map_pmap.pr_mapname);
        mptr->map_file = fptr;
        fptr->file_ref = 1;
        fptr->file_fd = -1;
        P->num_files++;

        /*
         * To figure out which map_info_t instances correspond to the mappings
         * for this load object we try to obtain the start and end address
         * for each section of our in-memory ELF image. If successful, we
         * walk down the list of addresses and the list of map_info_t
         * instances in lock step to correctly find the mappings that
         * correspond to this load object.
         */
        if ((fptr->file_saddrs = get_saddrs(P, mptr->map_pmap.pr_vaddr,
            &fptr->file_nsaddrs)) == NULL)
                return (fptr);

        mp = P->mappings;
        i = 0;
        while (mp < P->mappings + P->map_count && i < fptr->file_nsaddrs) {

                /* Calculate the start and end of the mapping and section */
                mstart = mp->map_pmap.pr_vaddr;
                mend = mp->map_pmap.pr_vaddr + mp->map_pmap.pr_size;
                sstart = fptr->file_saddrs[i];
                send = fptr->file_saddrs[i + 1];

                if (mend <= sstart) {
                        /* This mapping is below the current section */
                        mp++;
                } else if (mstart >= send) {
                        /* This mapping is above the current section */
                        i += 2;
                } else {
                        /* This mapping overlaps the current section */
                        if (mp->map_file == NULL) {
                                dprintf("file_info_new: associating "
                                    "segment at %p\n",
                                    (void *)mp->map_pmap.pr_vaddr);
                                mp->map_file = fptr;
                                fptr->file_ref++;
                        } else {
                                dprintf("file_info_new: segment at %p "
                                    "already associated with %s\n",
                                    (void *)mp->map_pmap.pr_vaddr,
                                    (mp == mptr ? "this file" :
                                    mp->map_file->file_pname));
                        }
                        mp++;
                }
        }

        return (fptr);
}

/*
 * Deallocation function for a file_info_t
 */
static void
file_info_free(struct ps_prochandle *P, file_info_t *fptr)
{
        if (--fptr->file_ref == 0) {
                list_unlink(fptr);
                if (fptr->file_symtab.sym_elf) {
                        (void) elf_end(fptr->file_symtab.sym_elf);
                        free(fptr->file_symtab.sym_elfmem);
                }
                free(fptr->file_symtab.sym_byname);
                free(fptr->file_symtab.sym_byaddr);

                if (fptr->file_dynsym.sym_elf) {
                        (void) elf_end(fptr->file_dynsym.sym_elf);
                        free(fptr->file_dynsym.sym_elfmem);
                }
                free(fptr->file_dynsym.sym_byname);
                free(fptr->file_dynsym.sym_byaddr);

                free(fptr->file_lo);
                free(fptr->file_lname);
                free(fptr->file_rname);
                if (fptr->file_elf)
                        (void) elf_end(fptr->file_elf);
                free(fptr->file_elfmem);
                if (fptr->file_fd >= 0)
                        (void) close(fptr->file_fd);
                if (fptr->file_ctfp) {
                        ctf_close(fptr->file_ctfp);
                        free(fptr->file_ctf_buf);
                }
                free(fptr->file_saddrs);
                free(fptr);
                P->num_files--;
        }
}

/*
 * Deallocation function for a map_info_t
 */
static void
map_info_free(struct ps_prochandle *P, map_info_t *mptr)
{
        file_info_t *fptr;

        if ((fptr = mptr->map_file) != NULL) {
                if (fptr->file_map == mptr)
                        fptr->file_map = NULL;
                file_info_free(P, fptr);
        }
        if (P->execname && mptr == P->map_exec) {
                free(P->execname);
                P->execname = NULL;
        }
        if (P->auxv && (mptr == P->map_exec || mptr == P->map_ldso)) {
                free(P->auxv);
                P->auxv = NULL;
                P->nauxv = 0;
        }
        if (mptr == P->map_exec)
                P->map_exec = NULL;
        if (mptr == P->map_ldso)
                P->map_ldso = NULL;
}

/*
 * Call-back function for librtld_db to iterate through all of its shared
 * libraries.  We use this to get the load object names for the mappings.
 */
static int
map_iter(const rd_loadobj_t *lop, void *cd)
{
        char buf[PATH_MAX];
        struct ps_prochandle *P = cd;
        map_info_t *mptr;
        file_info_t *fptr;

        dprintf("encountered rd object at %p\n", (void *)lop->rl_base);

        if ((mptr = Paddr2mptr(P, lop->rl_base)) == NULL) {
                dprintf("map_iter: base address doesn't match any mapping\n");
                return (1); /* Base address does not match any mapping */
        }

        if ((fptr = mptr->map_file) == NULL &&
            (fptr = file_info_new(P, mptr)) == NULL) {
                dprintf("map_iter: failed to allocate a new file_info_t\n");
                return (1); /* Failed to allocate a new file_info_t */
        }

        if ((fptr->file_lo == NULL) &&
            (fptr->file_lo = malloc(sizeof (rd_loadobj_t))) == NULL) {
                dprintf("map_iter: failed to allocate rd_loadobj_t\n");
                file_info_free(P, fptr);
                return (1); /* Failed to allocate rd_loadobj_t */
        }

        fptr->file_map = mptr;
        *fptr->file_lo = *lop;

        fptr->file_lo->rl_plt_base = fptr->file_plt_base;
        fptr->file_lo->rl_plt_size = fptr->file_plt_size;

        if (fptr->file_lname) {
                free(fptr->file_lname);
                fptr->file_lname = NULL;
                fptr->file_lbase = NULL;
        }
        if (fptr->file_rname) {
                free(fptr->file_rname);
                fptr->file_rname = NULL;
                fptr->file_rbase = NULL;
        }

        if (Pread_string(P, buf, sizeof (buf), lop->rl_nameaddr) > 0) {
                if ((fptr->file_lname = strdup(buf)) != NULL)
                        fptr->file_lbase = basename(fptr->file_lname);
        } else {
                dprintf("map_iter: failed to read string at %p\n",
                    (void *)lop->rl_nameaddr);
        }

        if ((Pfindmap(P, mptr, buf, sizeof (buf)) != NULL) &&
            ((fptr->file_rname = strdup(buf)) != NULL))
                fptr->file_rbase = basename(fptr->file_rname);

        dprintf("loaded rd object %s lmid %lx\n",
            fptr->file_lname ? buf : "<NULL>", lop->rl_lmident);
        return (1);
}

static void
map_set(struct ps_prochandle *P, map_info_t *mptr, const char *lname)
{
        file_info_t *fptr;
        char buf[PATH_MAX];

        if ((fptr = mptr->map_file) == NULL &&
            (fptr = file_info_new(P, mptr)) == NULL)
                return; /* Failed to allocate a new file_info_t */

        fptr->file_map = mptr;

        if ((fptr->file_lo == NULL) &&
            (fptr->file_lo = malloc(sizeof (rd_loadobj_t))) == NULL) {
                file_info_free(P, fptr);
                return; /* Failed to allocate rd_loadobj_t */
        }

        (void) memset(fptr->file_lo, 0, sizeof (rd_loadobj_t));
        fptr->file_lo->rl_base = mptr->map_pmap.pr_vaddr;
        fptr->file_lo->rl_bend =
            mptr->map_pmap.pr_vaddr + mptr->map_pmap.pr_size;

        fptr->file_lo->rl_plt_base = fptr->file_plt_base;
        fptr->file_lo->rl_plt_size = fptr->file_plt_size;

        if ((fptr->file_lname == NULL) &&
            (fptr->file_lname = strdup(lname)) != NULL)
                fptr->file_lbase = basename(fptr->file_lname);

        if ((Pfindmap(P, mptr, buf, sizeof (buf)) != NULL) &&
            ((fptr->file_rname = strdup(buf)) != NULL))
                fptr->file_rbase = basename(fptr->file_rname);
}

static void
load_static_maps(struct ps_prochandle *P)
{
        map_info_t *mptr;

        /*
         * Construct the map for the a.out.
         */
        if ((mptr = object_name_to_map(P, PR_LMID_EVERY, PR_OBJ_EXEC)) != NULL)
                map_set(P, mptr, "a.out");

        /*
         * If the dynamic linker exists for this process,
         * construct the map for it.
         */
        if (Pgetauxval(P, AT_BASE) != -1L &&
            (mptr = object_name_to_map(P, PR_LMID_EVERY, PR_OBJ_LDSO)) != NULL)
                map_set(P, mptr, "ld.so.1");
}

int
Preadmaps(struct ps_prochandle *P, prmap_t **Pmapp, ssize_t *nmapp)
{
        return (P->ops.pop_read_maps(P, Pmapp, nmapp, P->data));
}

/*
 * Go through all the address space mappings, validating or updating
 * the information already gathered, or gathering new information.
 *
 * This function is only called when we suspect that the mappings have changed
 * because this is the first time we're calling it or because of rtld activity.
 */
void
Pupdate_maps(struct ps_prochandle *P)
{
        prmap_t *Pmap = NULL;
        prmap_t *pmap;
        ssize_t nmap;
        int i;
        uint_t oldmapcount;
        map_info_t *newmap, *newp;
        map_info_t *mptr;

        if (P->info_valid || P->state == PS_UNDEAD)
                return;

        Preadauxvec(P);

        if (Preadmaps(P, &Pmap, &nmap) != 0)
                return;

        if ((newmap = calloc(1, nmap * sizeof (map_info_t))) == NULL)
                return;

        /*
         * We try to merge any file information we may have for existing
         * mappings, to avoid having to rebuild the file info.
         */
        mptr = P->mappings;
        pmap = Pmap;
        newp = newmap;
        oldmapcount = P->map_count;
        for (i = 0; i < nmap; i++, pmap++, newp++) {

                if (oldmapcount == 0) {
                        /*
                         * We've exhausted all the old mappings.  Every new
                         * mapping should be added.
                         */
                        newp->map_pmap = *pmap;

                } else if (pmap->pr_vaddr == mptr->map_pmap.pr_vaddr &&
                    pmap->pr_size == mptr->map_pmap.pr_size &&
                    pmap->pr_offset == mptr->map_pmap.pr_offset &&
                    (pmap->pr_mflags & ~(MA_BREAK | MA_STACK)) ==
                    (mptr->map_pmap.pr_mflags & ~(MA_BREAK | MA_STACK)) &&
                    pmap->pr_pagesize == mptr->map_pmap.pr_pagesize &&
                    pmap->pr_shmid == mptr->map_pmap.pr_shmid &&
                    strcmp(pmap->pr_mapname, mptr->map_pmap.pr_mapname) == 0) {

                        /*
                         * This mapping matches exactly.  Copy over the old
                         * mapping, taking care to get the latest flags.
                         * Make sure the associated file_info_t is updated
                         * appropriately.
                         */
                        *newp = *mptr;
                        if (P->map_exec == mptr)
                                P->map_exec = newp;
                        if (P->map_ldso == mptr)
                                P->map_ldso = newp;
                        newp->map_pmap.pr_mflags = pmap->pr_mflags;
                        if (mptr->map_file != NULL &&
                            mptr->map_file->file_map == mptr)
                                mptr->map_file->file_map = newp;
                        oldmapcount--;
                        mptr++;

                } else if (pmap->pr_vaddr + pmap->pr_size >
                    mptr->map_pmap.pr_vaddr) {

                        /*
                         * The old mapping doesn't exist any more, remove it
                         * from the list.
                         */
                        map_info_free(P, mptr);
                        oldmapcount--;
                        i--;
                        newp--;
                        pmap--;
                        mptr++;

                } else {

                        /*
                         * This is a new mapping, add it directly.
                         */
                        newp->map_pmap = *pmap;
                }
        }

        /*
         * Free any old maps
         */
        while (oldmapcount) {
                map_info_free(P, mptr);
                oldmapcount--;
                mptr++;
        }

        free(Pmap);
        free(P->mappings);
        P->mappings = newmap;
        P->map_count = P->map_alloc = nmap;
        P->info_valid = 1;

        /*
         * Consult librtld_db to get the load object
         * names for all of the shared libraries.
         */
        if (P->rap != NULL)
                (void) rd_loadobj_iter(P->rap, map_iter, P);
}

/*
 * Update all of the mappings and rtld_db as if by Pupdate_maps(), and then
 * forcibly cache all of the symbol tables associated with all object files.
 */
void
Pupdate_syms(struct ps_prochandle *P)
{
        file_info_t *fptr;
        int i;

        Pupdate_maps(P);

        for (i = 0, fptr = list_next(&P->file_head); i < P->num_files;
            i++, fptr = list_next(fptr)) {
                Pbuild_file_symtab(P, fptr);
                (void) Pbuild_file_ctf(P, fptr);
        }
}

/*
 * Return the librtld_db agent handle for the victim process.
 * The handle will become invalid at the next successful exec() and the
 * client (caller of proc_rd_agent()) must not use it beyond that point.
 * If the process is already dead, we've already tried our best to
 * create the agent during core file initialization.
 */
rd_agent_t *
Prd_agent(struct ps_prochandle *P)
{
        if (P->rap == NULL && P->state != PS_DEAD && P->state != PS_IDLE) {
                Pupdate_maps(P);
                if (P->num_files == 0)
                        load_static_maps(P);
                rd_log(_libproc_debug);
                if ((P->rap = rd_new(P)) != NULL)
                        (void) rd_loadobj_iter(P->rap, map_iter, P);
        }
        return (P->rap);
}

/*
 * Return the prmap_t structure containing 'addr', but only if it
 * is in the dynamic linker's link map and is the text section.
 */
const prmap_t *
Paddr_to_text_map(struct ps_prochandle *P, uintptr_t addr)
{
        map_info_t *mptr;

        if (!P->info_valid)
                Pupdate_maps(P);

        if ((mptr = Paddr2mptr(P, addr)) != NULL) {
                file_info_t *fptr = build_map_symtab(P, mptr);
                const prmap_t *pmp = &mptr->map_pmap;

                /*
                 * Assume that if rl_data_base is NULL, it means that no
                 * data section was found for this load object, and that
                 * a section must be text. Otherwise, a section will be
                 * text unless it ends above the start of the data
                 * section.
                 */
                if (fptr != NULL && fptr->file_lo != NULL &&
                    (fptr->file_lo->rl_data_base == 0 ||
                    pmp->pr_vaddr + pmp->pr_size <=
                    fptr->file_lo->rl_data_base))
                        return (pmp);
        }

        return (NULL);
}

/*
 * Return the prmap_t structure containing 'addr' (no restrictions on
 * the type of mapping).
 */
const prmap_t *
Paddr_to_map(struct ps_prochandle *P, uintptr_t addr)
{
        map_info_t *mptr;

        if (!P->info_valid)
                Pupdate_maps(P);

        if ((mptr = Paddr2mptr(P, addr)) != NULL)
                return (&mptr->map_pmap);

        return (NULL);
}

/*
 * Convert a full or partial load object name to the prmap_t for its
 * corresponding primary text mapping.
 */
const prmap_t *
Plmid_to_map(struct ps_prochandle *P, Lmid_t lmid, const char *name)
{
        map_info_t *mptr;

        if (name == PR_OBJ_EVERY)
                return (NULL); /* A reasonable mistake */

        if ((mptr = object_name_to_map(P, lmid, name)) != NULL)
                return (&mptr->map_pmap);

        return (NULL);
}

const prmap_t *
Pname_to_map(struct ps_prochandle *P, const char *name)
{
        return (Plmid_to_map(P, PR_LMID_EVERY, name));
}

const rd_loadobj_t *
Paddr_to_loadobj(struct ps_prochandle *P, uintptr_t addr)
{
        map_info_t *mptr;

        if (!P->info_valid)
                Pupdate_maps(P);

        if ((mptr = Paddr2mptr(P, addr)) == NULL)
                return (NULL);

        /*
         * By building the symbol table, we implicitly bring the PLT
         * information up to date in the load object.
         */
        (void) build_map_symtab(P, mptr);

        return (mptr->map_file->file_lo);
}

const rd_loadobj_t *
Plmid_to_loadobj(struct ps_prochandle *P, Lmid_t lmid, const char *name)
{
        map_info_t *mptr;

        if (name == PR_OBJ_EVERY)
                return (NULL);

        if ((mptr = object_name_to_map(P, lmid, name)) == NULL)
                return (NULL);

        /*
         * By building the symbol table, we implicitly bring the PLT
         * information up to date in the load object.
         */
        (void) build_map_symtab(P, mptr);

        return (mptr->map_file->file_lo);
}

const rd_loadobj_t *
Pname_to_loadobj(struct ps_prochandle *P, const char *name)
{
        return (Plmid_to_loadobj(P, PR_LMID_EVERY, name));
}

/*
 * We've been given a file_info_t which doesn't have any CTF. However, it may
 * have information that's in a format that we could convert if on the fly.
 */
static ctf_file_t *
Pconvert_file_ctf(file_info_t *fptr)
{
        int err;
        ctf_file_t *fp;
        char errmsg[1024];

        /*
         * Provide an opt in.
         */
        if (getenv("LIBPROC_CTFCONVERT") == NULL)
                return (NULL);

        /*
         * If we've already attempted to call this, then that's it. No reason to
         * pretend we'll be more successful again another time.
         */
        if (fptr->file_cvt == B_TRUE)
                return (NULL);
        fptr->file_cvt = B_TRUE;

        fp = ctf_elfconvert(fptr->file_fd, fptr->file_elf, NULL, 1,
            0, &err, errmsg, sizeof (errmsg));
        if (fp == NULL)
                dprintf("failed to convert %s: %s\n", fptr->file_pname,
                    err == ECTF_CONVBKERR ? errmsg : ctf_errmsg(err));
        else
                fptr->file_ctfp = fp;

        return (NULL);
}

ctf_file_t *
Pbuild_file_ctf(struct ps_prochandle *P, file_info_t *fptr)
{
        ctf_sect_t ctdata, symtab, strtab;
        sym_tbl_t *symp;
        int err;

        if (fptr->file_ctfp != NULL)
                return (fptr->file_ctfp);

        Pbuild_file_symtab(P, fptr);

        if (fptr->file_ctf_size == 0) {
                return (Pconvert_file_ctf(fptr));
        }

        symp = fptr->file_ctf_dyn ? &fptr->file_dynsym : &fptr->file_symtab;
        if (symp->sym_data_pri == NULL)
                return (NULL);

        /*
         * The buffer may alread be allocated if this is a core file that
         * contained CTF data for this file.
         */
        if (fptr->file_ctf_buf == NULL) {
                fptr->file_ctf_buf = malloc(fptr->file_ctf_size);
                if (fptr->file_ctf_buf == NULL) {
                        dprintf("failed to allocate ctf buffer\n");
                        return (NULL);
                }

                if (pread(fptr->file_fd, fptr->file_ctf_buf,
                    fptr->file_ctf_size, fptr->file_ctf_off) !=
                    fptr->file_ctf_size) {
                        free(fptr->file_ctf_buf);
                        fptr->file_ctf_buf = NULL;
                        dprintf("failed to read ctf data\n");
                        return (NULL);
                }
        }

        ctdata.cts_name = ".SUNW_ctf";
        ctdata.cts_type = SHT_PROGBITS;
        ctdata.cts_flags = 0;
        ctdata.cts_data = fptr->file_ctf_buf;
        ctdata.cts_size = fptr->file_ctf_size;
        ctdata.cts_entsize = 1;
        ctdata.cts_offset = 0;

        symtab.cts_name = fptr->file_ctf_dyn ? ".dynsym" : ".symtab";
        symtab.cts_type = symp->sym_hdr_pri.sh_type;
        symtab.cts_flags = symp->sym_hdr_pri.sh_flags;
        symtab.cts_data = symp->sym_data_pri->d_buf;
        symtab.cts_size = symp->sym_hdr_pri.sh_size;
        symtab.cts_entsize = symp->sym_hdr_pri.sh_entsize;
        symtab.cts_offset = symp->sym_hdr_pri.sh_offset;

        strtab.cts_name = fptr->file_ctf_dyn ? ".dynstr" : ".strtab";
        strtab.cts_type = symp->sym_strhdr.sh_type;
        strtab.cts_flags = symp->sym_strhdr.sh_flags;
        strtab.cts_data = symp->sym_strs;
        strtab.cts_size = symp->sym_strhdr.sh_size;
        strtab.cts_entsize = symp->sym_strhdr.sh_entsize;
        strtab.cts_offset = symp->sym_strhdr.sh_offset;

        fptr->file_ctfp = ctf_bufopen(&ctdata, &symtab, &strtab, &err);
        if (fptr->file_ctfp == NULL) {
                dprintf("ctf_bufopen() failed, error code %d\n", err);
                free(fptr->file_ctf_buf);
                fptr->file_ctf_buf = NULL;
                return (NULL);
        }

        dprintf("loaded %lu bytes of CTF data for %s\n",
            (ulong_t)fptr->file_ctf_size, fptr->file_pname);

        return (fptr->file_ctfp);
}

ctf_file_t *
Paddr_to_ctf(struct ps_prochandle *P, uintptr_t addr)
{
        map_info_t *mptr;
        file_info_t *fptr;

        if (!P->info_valid)
                Pupdate_maps(P);

        if ((mptr = Paddr2mptr(P, addr)) == NULL ||
            (fptr = mptr->map_file) == NULL)
                return (NULL);

        return (Pbuild_file_ctf(P, fptr));
}

ctf_file_t *
Plmid_to_ctf(struct ps_prochandle *P, Lmid_t lmid, const char *name)
{
        map_info_t *mptr;
        file_info_t *fptr = NULL;

        if (name == PR_OBJ_EVERY)
                return (NULL);

        /*
         * While most idle files are all ELF objects, not all of them have
         * mapping information available. There's nothing which would make
         * sense to fake up for ET_REL. Instead, if we're being asked for their
         * executable object and we know that the information is valid and they
         * only have a single file, we jump straight to that file pointer.
         */
        if (P->state == PS_IDLE && name == PR_OBJ_EXEC && P->info_valid == 1 &&
            P->num_files == 1 && P->mappings == NULL) {
                fptr = list_next(&P->file_head);
        }

        if (fptr == NULL) {
                if ((mptr = object_name_to_map(P, lmid, name)) == NULL ||
                    (fptr = mptr->map_file) == NULL)
                        return (NULL);
        }

        return (Pbuild_file_ctf(P, fptr));
}

ctf_file_t *
Pname_to_ctf(struct ps_prochandle *P, const char *name)
{
        return (Plmid_to_ctf(P, PR_LMID_EVERY, name));
}

void
Preadauxvec(struct ps_prochandle *P)
{
        if (P->auxv != NULL) {
                free(P->auxv);
                P->auxv = NULL;
                P->nauxv = 0;
        }

        P->ops.pop_read_aux(P, &P->auxv, &P->nauxv, P->data);
}

/*
 * Return a requested element from the process's aux vector.
 * Return -1 on failure (this is adequate for our purposes).
 */
long
Pgetauxval(struct ps_prochandle *P, int type)
{
        auxv_t *auxv;

        if (P->auxv == NULL)
                Preadauxvec(P);

        if (P->auxv == NULL)
                return (-1);

        for (auxv = P->auxv; auxv->a_type != AT_NULL; auxv++) {
                if (auxv->a_type == type)
                        return (auxv->a_un.a_val);
        }

        return (-1);
}

/*
 * Return a pointer to our internal copy of the process's aux vector.
 * The caller should not hold on to this pointer across any libproc calls.
 */
const auxv_t *
Pgetauxvec(struct ps_prochandle *P)
{
        static const auxv_t empty = { AT_NULL, 0L };

        if (P->auxv == NULL)
                Preadauxvec(P);

        if (P->auxv == NULL)
                return (&empty);

        return (P->auxv);
}

/*
 * Return 1 if the given mapping corresponds to the given file_info_t's
 * load object; return 0 otherwise.
 */
static int
is_mapping_in_file(struct ps_prochandle *P, map_info_t *mptr, file_info_t *fptr)
{
        prmap_t *pmap = &mptr->map_pmap;
        rd_loadobj_t *lop = fptr->file_lo;
        uint_t i;
        uintptr_t mstart, mend, sstart, send;

        /*
         * We can get for free the start address of the text and data
         * sections of the load object. Start by seeing if the mapping
         * encloses either of these.
         */
        if ((pmap->pr_vaddr <= lop->rl_base &&
            lop->rl_base < pmap->pr_vaddr + pmap->pr_size) ||
            (pmap->pr_vaddr <= lop->rl_data_base &&
            lop->rl_data_base < pmap->pr_vaddr + pmap->pr_size))
                return (1);

        /*
         * It's still possible that this mapping correponds to the load
         * object. Consider the example of a mapping whose start and end
         * addresses correspond to those of the load object's text section.
         * If the mapping splits, e.g. as a result of a segment demotion,
         * then although both mappings are still backed by the same section,
         * only one will be seen to enclose that section's start address.
         * Thus, to be rigorous, we ask not whether this mapping encloses
         * the start of a section, but whether there exists a section that
         * overlaps this mapping.
         *
         * If we don't already have the section addresses, and we successfully
         * get them, then we cache them in case we come here again.
         */
        if (fptr->file_saddrs == NULL &&
            (fptr->file_saddrs = get_saddrs(P,
            fptr->file_map->map_pmap.pr_vaddr, &fptr->file_nsaddrs)) == NULL)
                return (0);

        mstart = mptr->map_pmap.pr_vaddr;
        mend = mptr->map_pmap.pr_vaddr + mptr->map_pmap.pr_size;
        for (i = 0; i < fptr->file_nsaddrs; i += 2) {
                /* Does this section overlap the mapping? */
                sstart = fptr->file_saddrs[i];
                send = fptr->file_saddrs[i + 1];
                if (!(mend <= sstart || mstart >= send))
                        return (1);
        }

        return (0);
}

/*
 * Find or build the symbol table for the given mapping.
 */
static file_info_t *
build_map_symtab(struct ps_prochandle *P, map_info_t *mptr)
{
        prmap_t *pmap = &mptr->map_pmap;
        file_info_t *fptr;
        uint_t i;

        if ((fptr = mptr->map_file) != NULL) {
                Pbuild_file_symtab(P, fptr);
                return (fptr);
        }

        if (pmap->pr_mapname[0] == '\0')
                return (NULL);

        /*
         * Attempt to find a matching file.
         * (A file can be mapped at several different addresses.)
         */
        for (i = 0, fptr = list_next(&P->file_head); i < P->num_files;
            i++, fptr = list_next(fptr)) {
                if (strcmp(fptr->file_pname, pmap->pr_mapname) == 0 &&
                    fptr->file_lo && is_mapping_in_file(P, mptr, fptr)) {
                        mptr->map_file = fptr;
                        fptr->file_ref++;
                        Pbuild_file_symtab(P, fptr);
                        return (fptr);
                }
        }

        /*
         * If we need to create a new file_info structure, iterate
         * through the load objects in order to attempt to connect
         * this new file with its primary text mapping.  We again
         * need to handle ld.so as a special case because we need
         * to be able to bootstrap librtld_db.
         */
        if ((fptr = file_info_new(P, mptr)) == NULL)
                return (NULL);

        if (P->map_ldso != mptr) {
                if (P->rap != NULL)
                        (void) rd_loadobj_iter(P->rap, map_iter, P);
                else
                        (void) Prd_agent(P);
        } else {
                fptr->file_map = mptr;
        }

        /*
         * If librtld_db wasn't able to help us connect the file to a primary
         * text mapping, set file_map to the current mapping because we require
         * fptr->file_map to be set in Pbuild_file_symtab.  librtld_db may be
         * unaware of what's going on in the rare case that a legitimate ELF
         * file has been mmap(2)ed into the process address space *without*
         * the use of dlopen(3x).
         */
        if (fptr->file_map == NULL)
                fptr->file_map = mptr;

        Pbuild_file_symtab(P, fptr);

        return (fptr);
}

static int
read_ehdr32(struct ps_prochandle *P, Elf32_Ehdr *ehdr, uint_t *phnum,
    uintptr_t addr)
{
        if (Pread(P, ehdr, sizeof (*ehdr), addr) != sizeof (*ehdr))
                return (-1);

        if (ehdr->e_ident[EI_MAG0] != ELFMAG0 ||
            ehdr->e_ident[EI_MAG1] != ELFMAG1 ||
            ehdr->e_ident[EI_MAG2] != ELFMAG2 ||
            ehdr->e_ident[EI_MAG3] != ELFMAG3 ||
            ehdr->e_ident[EI_CLASS] != ELFCLASS32 ||
#ifdef _BIG_ENDIAN
            ehdr->e_ident[EI_DATA] != ELFDATA2MSB ||
#else
            ehdr->e_ident[EI_DATA] != ELFDATA2LSB ||
#endif
            ehdr->e_ident[EI_VERSION] != EV_CURRENT)
                return (-1);

        if ((*phnum = ehdr->e_phnum) == PN_XNUM) {
                Elf32_Shdr shdr0;

                if (ehdr->e_shoff == 0 || ehdr->e_shentsize < sizeof (shdr0) ||
                    Pread(P, &shdr0, sizeof (shdr0), addr + ehdr->e_shoff) !=
                    sizeof (shdr0))
                        return (-1);

                if (shdr0.sh_info != 0)
                        *phnum = shdr0.sh_info;
        }

        return (0);
}

static int
read_dynamic_phdr32(struct ps_prochandle *P, const Elf32_Ehdr *ehdr,
    uint_t phnum, Elf32_Phdr *phdr, uintptr_t addr)
{
        uint_t i;

        for (i = 0; i < phnum; i++) {
                uintptr_t a = addr + ehdr->e_phoff + i * ehdr->e_phentsize;
                if (Pread(P, phdr, sizeof (*phdr), a) != sizeof (*phdr))
                        return (-1);

                if (phdr->p_type == PT_DYNAMIC)
                        return (0);
        }

        return (-1);
}

#ifdef _LP64
static int
read_ehdr64(struct ps_prochandle *P, Elf64_Ehdr *ehdr, uint_t *phnum,
    uintptr_t addr)
{
        if (Pread(P, ehdr, sizeof (Elf64_Ehdr), addr) != sizeof (Elf64_Ehdr))
                return (-1);

        if (ehdr->e_ident[EI_MAG0] != ELFMAG0 ||
            ehdr->e_ident[EI_MAG1] != ELFMAG1 ||
            ehdr->e_ident[EI_MAG2] != ELFMAG2 ||
            ehdr->e_ident[EI_MAG3] != ELFMAG3 ||
            ehdr->e_ident[EI_CLASS] != ELFCLASS64 ||
#ifdef _BIG_ENDIAN
            ehdr->e_ident[EI_DATA] != ELFDATA2MSB ||
#else
            ehdr->e_ident[EI_DATA] != ELFDATA2LSB ||
#endif
            ehdr->e_ident[EI_VERSION] != EV_CURRENT)
                return (-1);

        if ((*phnum = ehdr->e_phnum) == PN_XNUM) {
                Elf64_Shdr shdr0;

                if (ehdr->e_shoff == 0 || ehdr->e_shentsize < sizeof (shdr0) ||
                    Pread(P, &shdr0, sizeof (shdr0), addr + ehdr->e_shoff) !=
                    sizeof (shdr0))
                        return (-1);

                if (shdr0.sh_info != 0)
                        *phnum = shdr0.sh_info;
        }

        return (0);
}

static int
read_dynamic_phdr64(struct ps_prochandle *P, const Elf64_Ehdr *ehdr,
    uint_t phnum, Elf64_Phdr *phdr, uintptr_t addr)
{
        uint_t i;

        for (i = 0; i < phnum; i++) {
                uintptr_t a = addr + ehdr->e_phoff + i * ehdr->e_phentsize;
                if (Pread(P, phdr, sizeof (*phdr), a) != sizeof (*phdr))
                        return (-1);

                if (phdr->p_type == PT_DYNAMIC)
                        return (0);
        }

        return (-1);
}
#endif  /* _LP64 */

/*
 * The text segment for each load object contains the elf header and
 * program headers. We can use this information to determine if the
 * file that corresponds to the load object is the same file that
 * was loaded into the process's address space. There can be a discrepency
 * if a file is recompiled after the process is started or if the target
 * represents a core file from a differently configured system -- two
 * common examples. The DT_CHECKSUM entry in the dynamic section
 * provides an easy method of comparison. It is important to note that
 * the dynamic section usually lives in the data segment, but the meta
 * data we use to find the dynamic section lives in the text segment so
 * if either of those segments is absent we can't proceed.
 *
 * We're looking through the elf file for several items: the symbol tables
 * (both dynsym and symtab), the procedure linkage table (PLT) base,
 * size, and relocation base, and the CTF information. Most of this can
 * be recovered from the loaded image of the file itself, the exceptions
 * being the symtab and CTF data.
 *
 * First we try to open the file that we think corresponds to the load
 * object, if the DT_CHECKSUM values match, we're all set, and can simply
 * recover all the information we need from the file. If the values of
 * DT_CHECKSUM don't match, or if we can't access the file for whatever
 * reasaon, we fake up a elf file to use in its stead. If we can't read
 * the elf data in the process's address space, we fall back to using
 * the file even though it may give inaccurate information.
 *
 * The elf file that we fake up has to consist of sections for the
 * dynsym, the PLT and the dynamic section. Note that in the case of a
 * core file, we'll get the CTF data in the file_info_t later on from
 * a section embedded the core file (if it's present).
 *
 * file_differs() conservatively looks for mismatched files, identifying
 * a match when there is any ambiguity (since that's the legacy behavior).
 */
static int
file_differs(struct ps_prochandle *P, Elf *elf, file_info_t *fptr)
{
        Elf_Scn *scn;
        GElf_Shdr shdr;
        GElf_Dyn dyn;
        Elf_Data *data;
        uint_t i, ndyn;
        GElf_Xword cksum;
        uintptr_t addr;

        if (fptr->file_map == NULL)
                return (0);

        if ((Pcontent(P) & (CC_CONTENT_TEXT | CC_CONTENT_DATA)) !=
            (CC_CONTENT_TEXT | CC_CONTENT_DATA))
                return (0);

        /*
         * First, we find the checksum value in the elf file.
         */
        scn = NULL;
        while ((scn = elf_nextscn(elf, scn)) != NULL) {
                if (gelf_getshdr(scn, &shdr) != NULL &&
                    shdr.sh_type == SHT_DYNAMIC)
                        goto found_shdr;
        }
        return (0);

found_shdr:
        if ((data = elf_getdata(scn, NULL)) == NULL)
                return (0);

        if (P->status.pr_dmodel == PR_MODEL_ILP32)
                ndyn = shdr.sh_size / sizeof (Elf32_Dyn);
#ifdef _LP64
        else if (P->status.pr_dmodel == PR_MODEL_LP64)
                ndyn = shdr.sh_size / sizeof (Elf64_Dyn);
#endif
        else
                return (0);

        for (i = 0; i < ndyn; i++) {
                if (gelf_getdyn(data, i, &dyn) != NULL &&
                    dyn.d_tag == DT_CHECKSUM)
                        goto found_cksum;
        }

        /*
         * The in-memory ELF has no DT_CHECKSUM section, but we will report it
         * as matching the file anyhow.
         */
        return (0);

found_cksum:
        cksum = dyn.d_un.d_val;
        dprintf("elf cksum value is %llx\n", (u_longlong_t)cksum);

        /*
         * Get the base of the text mapping that corresponds to this file.
         */
        addr = fptr->file_map->map_pmap.pr_vaddr;

        if (P->status.pr_dmodel == PR_MODEL_ILP32) {
                Elf32_Ehdr ehdr;
                Elf32_Phdr phdr;
                Elf32_Dyn dync, *dynp;
                uint_t phnum, i;

                if (read_ehdr32(P, &ehdr, &phnum, addr) != 0 ||
                    read_dynamic_phdr32(P, &ehdr, phnum, &phdr, addr) != 0)
                        return (0);

                if (ehdr.e_type == ET_DYN)
                        phdr.p_vaddr += addr;
                if ((dynp = malloc(phdr.p_filesz)) == NULL)
                        return (0);
                dync.d_tag = DT_NULL;
                if (Pread(P, dynp, phdr.p_filesz, phdr.p_vaddr) !=
                    phdr.p_filesz) {
                        free(dynp);
                        return (0);
                }

                for (i = 0; i < phdr.p_filesz / sizeof (Elf32_Dyn); i++) {
                        if (dynp[i].d_tag == DT_CHECKSUM)
                                dync = dynp[i];
                }

                free(dynp);

                if (dync.d_tag != DT_CHECKSUM)
                        return (0);

                dprintf("image cksum value is %llx\n",
                    (u_longlong_t)dync.d_un.d_val);
                return (dync.d_un.d_val != cksum);
#ifdef _LP64
        } else if (P->status.pr_dmodel == PR_MODEL_LP64) {
                Elf64_Ehdr ehdr;
                Elf64_Phdr phdr;
                Elf64_Dyn dync, *dynp;
                uint_t phnum, i;

                if (read_ehdr64(P, &ehdr, &phnum, addr) != 0 ||
                    read_dynamic_phdr64(P, &ehdr, phnum, &phdr, addr) != 0)
                        return (0);

                if (ehdr.e_type == ET_DYN)
                        phdr.p_vaddr += addr;
                if ((dynp = malloc(phdr.p_filesz)) == NULL)
                        return (0);
                dync.d_tag = DT_NULL;
                if (Pread(P, dynp, phdr.p_filesz, phdr.p_vaddr) !=
                    phdr.p_filesz) {
                        free(dynp);
                        return (0);
                }

                for (i = 0; i < phdr.p_filesz / sizeof (Elf64_Dyn); i++) {
                        if (dynp[i].d_tag == DT_CHECKSUM)
                                dync = dynp[i];
                }

                free(dynp);

                if (dync.d_tag != DT_CHECKSUM)
                        return (0);

                dprintf("image cksum value is %llx\n",
                    (u_longlong_t)dync.d_un.d_val);
                return (dync.d_un.d_val != cksum);
#endif  /* _LP64 */
        }

        return (0);
}

/*
 * Read data from the specified process and construct an in memory
 * image of an ELF file that represents it well enough to let
 * us probe it for information.
 */
static Elf *
fake_elf(struct ps_prochandle *P, file_info_t *fptr)
{
        Elf *elf;
        uintptr_t addr;
        uint_t phnum;

        if (fptr->file_map == NULL)
                return (NULL);

        if ((Pcontent(P) & (CC_CONTENT_TEXT | CC_CONTENT_DATA)) !=
            (CC_CONTENT_TEXT | CC_CONTENT_DATA))
                return (NULL);

        addr = fptr->file_map->map_pmap.pr_vaddr;

        if (P->status.pr_dmodel == PR_MODEL_ILP32) {
                Elf32_Ehdr ehdr;
                Elf32_Phdr phdr;

                if ((read_ehdr32(P, &ehdr, &phnum, addr) != 0) ||
                    read_dynamic_phdr32(P, &ehdr, phnum, &phdr, addr) != 0)
                        return (NULL);

                elf = fake_elf32(P, fptr, addr, &ehdr, phnum, &phdr);
#ifdef _LP64
        } else {
                Elf64_Ehdr ehdr;
                Elf64_Phdr phdr;

                if (read_ehdr64(P, &ehdr, &phnum, addr) != 0 ||
                    read_dynamic_phdr64(P, &ehdr, phnum, &phdr, addr) != 0)
                        return (NULL);

                elf = fake_elf64(P, fptr, addr, &ehdr, phnum, &phdr);
#endif
        }

        return (elf);
}

/*
 * We wouldn't need these if qsort(3C) took an argument for the callback...
 */
static mutex_t sort_mtx = DEFAULTMUTEX;
static char *sort_strs;
static GElf_Sym *sort_syms;

int
byaddr_cmp_common(GElf_Sym *a, char *aname, GElf_Sym *b, char *bname)
{
        if (a->st_value < b->st_value)
                return (-1);
        if (a->st_value > b->st_value)
                return (1);

        /*
         * Prefer the function to the non-function.
         */
        if (GELF_ST_TYPE(a->st_info) != GELF_ST_TYPE(b->st_info)) {
                if (GELF_ST_TYPE(a->st_info) == STT_FUNC)
                        return (-1);
                if (GELF_ST_TYPE(b->st_info) == STT_FUNC)
                        return (1);
        }

        /*
         * Prefer the weak or strong global symbol to the local symbol.
         */
        if (GELF_ST_BIND(a->st_info) != GELF_ST_BIND(b->st_info)) {
                if (GELF_ST_BIND(b->st_info) == STB_LOCAL)
                        return (-1);
                if (GELF_ST_BIND(a->st_info) == STB_LOCAL)
                        return (1);
        }

        /*
         * Prefer the symbol that doesn't begin with a '$' since compilers and
         * other symbol generators often use it as a prefix.
         */
        if (*bname == '$')
                return (-1);
        if (*aname == '$')
                return (1);

        /*
         * Prefer the name with fewer leading underscores in the name.
         */
        while (*aname == '_' && *bname == '_') {
                aname++;
                bname++;
        }

        if (*bname == '_')
                return (-1);
        if (*aname == '_')
                return (1);

        /*
         * Prefer the symbol with the smaller size.
         */
        if (a->st_size < b->st_size)
                return (-1);
        if (a->st_size > b->st_size)
                return (1);

        /*
         * All other factors being equal, fall back to lexicographic order.
         */
        return (strcmp(aname, bname));
}

static int
byaddr_cmp(const void *aa, const void *bb)
{
        GElf_Sym *a = &sort_syms[*(uint_t *)aa];
        GElf_Sym *b = &sort_syms[*(uint_t *)bb];
        char *aname = sort_strs + a->st_name;
        char *bname = sort_strs + b->st_name;

        return (byaddr_cmp_common(a, aname, b, bname));
}

static int
byname_cmp(const void *aa, const void *bb)
{
        GElf_Sym *a = &sort_syms[*(uint_t *)aa];
        GElf_Sym *b = &sort_syms[*(uint_t *)bb];
        char *aname = sort_strs + a->st_name;
        char *bname = sort_strs + b->st_name;

        return (strcmp(aname, bname));
}

/*
 * Given a symbol index, look up the corresponding symbol from the
 * given symbol table.
 *
 * This function allows the caller to treat the symbol table as a single
 * logical entity even though there may be 2 actual ELF symbol tables
 * involved. See the comments in Pcontrol.h for details.
 */
static GElf_Sym *
symtab_getsym(sym_tbl_t *symtab, int ndx, GElf_Sym *dst)
{
        /* If index is in range of primary symtab, look it up there */
        if (ndx >= symtab->sym_symn_aux) {
                return (gelf_getsym(symtab->sym_data_pri,
                    ndx - symtab->sym_symn_aux, dst));
        }

        /* Not in primary: Look it up in the auxiliary symtab */
        return (gelf_getsym(symtab->sym_data_aux, ndx, dst));
}

void
optimize_symtab(sym_tbl_t *symtab)
{
        GElf_Sym *symp, *syms;
        uint_t i, *indexa, *indexb;
        size_t symn, strsz, count;

        if (symtab == NULL || symtab->sym_data_pri == NULL ||
            symtab->sym_byaddr != NULL)
                return;

        symn = symtab->sym_symn;
        strsz = symtab->sym_strsz;

        symp = syms = malloc(sizeof (GElf_Sym) * symn);
        if (symp == NULL) {
                dprintf("optimize_symtab: failed to malloc symbol array");
                return;
        }

        /*
         * First record all the symbols into a table and count up the ones
         * that we're interested in. We mark symbols as invalid by setting
         * the st_name to an illegal value.
         */
        for (i = 0, count = 0; i < symn; i++, symp++) {
                if (symtab_getsym(symtab, i, symp) != NULL &&
                    symp->st_name < strsz &&
                    IS_DATA_TYPE(GELF_ST_TYPE(symp->st_info)))
                        count++;
                else
                        symp->st_name = strsz;
        }

        /*
         * Allocate sufficient space for both tables and populate them
         * with the same symbols we just counted.
         */
        symtab->sym_count = count;
        indexa = symtab->sym_byaddr = calloc(sizeof (uint_t), count);
        indexb = symtab->sym_byname = calloc(sizeof (uint_t), count);
        if (indexa == NULL || indexb == NULL) {
                dprintf(
                    "optimize_symtab: failed to malloc symbol index arrays");
                symtab->sym_count = 0;
                if (indexa != NULL) {   /* First alloc succeeded. Free it */
                        free(indexa);
                        symtab->sym_byaddr = NULL;
                }
                free(syms);
                return;
        }
        for (i = 0, symp = syms; i < symn; i++, symp++) {
                if (symp->st_name < strsz)
                        *indexa++ = *indexb++ = i;
        }

        /*
         * Sort the two tables according to the appropriate criteria,
         * unless the user has overridden this behaviour.
         *
         * An example where we might not sort the tables is the relatively
         * unusual case of a process with very large symbol tables in which
         * we perform few lookups. In such a case the total time would be
         * dominated by the sort. It is difficult to determine a priori
         * how many lookups an arbitrary client will perform, and
         * hence whether the symbol tables should be sorted. We therefore
         * sort the tables by default, but provide the user with a
         * "chicken switch" in the form of the LIBPROC_NO_QSORT
         * environment variable.
         */
        if (!_libproc_no_qsort) {
                (void) mutex_lock(&sort_mtx);
                sort_strs = symtab->sym_strs;
                sort_syms = syms;

                qsort(symtab->sym_byaddr, count, sizeof (uint_t), byaddr_cmp);
                qsort(symtab->sym_byname, count, sizeof (uint_t), byname_cmp);

                sort_strs = NULL;
                sort_syms = NULL;
                (void) mutex_unlock(&sort_mtx);
        }

        free(syms);
}


static Elf *
build_fake_elf(struct ps_prochandle *P, file_info_t *fptr, GElf_Ehdr *ehdr,
    size_t *nshdrs, Elf_Data **shdata)
{
        size_t shstrndx;
        Elf_Scn *scn;
        Elf *elf;

        if ((elf = fake_elf(P, fptr)) == NULL ||
            elf_kind(elf) != ELF_K_ELF ||
            gelf_getehdr(elf, ehdr) == NULL ||
            elf_getshdrnum(elf, nshdrs) == -1 ||
            elf_getshdrstrndx(elf, &shstrndx) == -1 ||
            (scn = elf_getscn(elf, shstrndx)) == NULL ||
            (*shdata = elf_getdata(scn, NULL)) == NULL) {
                if (elf != NULL)
                        (void) elf_end(elf);
                dprintf("failed to fake up ELF file\n");
                return (NULL);
        }

        return (elf);
}

/*
 * Build the symbol table for the given mapped file.
 */
void
Pbuild_file_symtab(struct ps_prochandle *P, file_info_t *fptr)
{
        char objectfile[PATH_MAX];
        uint_t i;

        GElf_Ehdr ehdr;
        GElf_Sym s;

        Elf_Data *shdata;
        Elf_Scn *scn;
        Elf *elf;
        size_t nshdrs, shstrndx;

        struct {
                GElf_Shdr c_shdr;
                Elf_Data *c_data;
                const char *c_name;
        } *cp, *cache = NULL, *dyn = NULL, *plt = NULL, *ctf = NULL;

        if (fptr->file_init)
                return; /* We've already processed this file */

        /*
         * Mark the file_info struct as having the symbol table initialized
         * even if we fail below.  We tried once; we don't try again.
         */
        fptr->file_init = 1;

        if (elf_version(EV_CURRENT) == EV_NONE) {
                dprintf("libproc ELF version is more recent than libelf\n");
                return;
        }

        if (P->state == PS_DEAD || P->state == PS_IDLE) {
                char *name;
                /*
                 * If we're a not live, we can't open files from the /proc
                 * object directory; we have only the mapping and file names
                 * to guide us.  We prefer the file_lname, but need to handle
                 * the case of it being NULL in order to bootstrap: we first
                 * come here during rd_new() when the only information we have
                 * is interpreter name associated with the AT_BASE mapping.
                 *
                 * Also, if the zone associated with the core file seems
                 * to exists on this machine we'll try to open the object
                 * file within the zone.
                 */
                if (fptr->file_rname != NULL)
                        name = fptr->file_rname;
                else if (fptr->file_lname != NULL)
                        name = fptr->file_lname;
                else
                        name = fptr->file_pname;
                (void) strlcpy(objectfile, name, sizeof (objectfile));
        } else {
                (void) snprintf(objectfile, sizeof (objectfile),
                    "%s/%d/object/%s",
                    procfs_path, (int)P->pid, fptr->file_pname);
        }

        /*
         * Open the object file, create the elf file, and then get the elf
         * header and .shstrtab data buffer so we can process sections by
         * name. If anything goes wrong try to fake up an elf file from
         * the in-core elf image.
         */

        if (_libproc_incore_elf || (P->flags & INCORE)) {
                dprintf("Pbuild_file_symtab: using in-core data for: %s\n",
                    fptr->file_pname);

                if ((elf = build_fake_elf(P, fptr, &ehdr, &nshdrs, &shdata)) ==
                    NULL)
                        return;

        } else if ((fptr->file_fd = open(objectfile, O_RDONLY)) < 0) {
                dprintf("Pbuild_file_symtab: failed to open %s: %s\n",
                    objectfile, strerror(errno));

                if ((elf = build_fake_elf(P, fptr, &ehdr, &nshdrs, &shdata)) ==
                    NULL)
                        return;

        } else if ((elf = elf_begin(fptr->file_fd, ELF_C_READ, NULL)) == NULL ||
            elf_kind(elf) != ELF_K_ELF ||
            gelf_getehdr(elf, &ehdr) == NULL ||
            elf_getshdrnum(elf, &nshdrs) == -1 ||
            elf_getshdrstrndx(elf, &shstrndx) == -1 ||
            (scn = elf_getscn(elf, shstrndx)) == NULL ||
            (shdata = elf_getdata(scn, NULL)) == NULL) {
                int err = elf_errno();

                dprintf("failed to process ELF file %s: %s\n",
                    objectfile, (err == 0) ? "<null>" : elf_errmsg(err));
                (void) elf_end(elf);

                if ((elf = build_fake_elf(P, fptr, &ehdr, &nshdrs, &shdata)) ==
                    NULL)
                        return;

        } else if (file_differs(P, elf, fptr)) {
                Elf *newelf;

                /*
                 * Before we get too excited about this elf file, we'll check
                 * its checksum value against the value we have in memory. If
                 * they don't agree, we try to fake up a new elf file and
                 * proceed with that instead.
                 */
                dprintf("ELF file %s (%lx) doesn't match in-core image\n",
                    fptr->file_pname,
                    (ulong_t)fptr->file_map->map_pmap.pr_vaddr);

                if ((newelf = build_fake_elf(P, fptr, &ehdr, &nshdrs, &shdata))
                    != NULL) {
                        (void) elf_end(elf);
                        elf = newelf;
                        dprintf("switched to faked up ELF file\n");

                        /*
                         * Check to see if the file that we just discovered
                         * to be an imposter matches the execname that was
                         * determined by Pfindexec().  If it does, we (clearly)
                         * don't have the right binary, and we zero out
                         * execname before anyone gets hurt.
                         */
                        if (fptr->file_rname != NULL && P->execname != NULL &&
                            strcmp(fptr->file_rname, P->execname) == 0) {
                                dprintf("file/in-core image mismatch was "
                                    "on P->execname; discarding\n");
                                free(P->execname);
                                P->execname = NULL;
                        }
                }
        }

        if ((cache = malloc(nshdrs * sizeof (*cache))) == NULL) {
                dprintf("failed to malloc section cache for %s\n", objectfile);
                goto bad;
        }

        dprintf("processing ELF file %s\n", objectfile);
        fptr->file_class = ehdr.e_ident[EI_CLASS];
        fptr->file_etype = ehdr.e_type;
        fptr->file_elf = elf;
        fptr->file_shstrs = shdata->d_buf;
        fptr->file_shstrsz = shdata->d_size;

        /*
         * Iterate through each section, caching its section header, data
         * pointer, and name.  We use this for handling sh_link values below.
         */
        for (cp = cache + 1, scn = NULL; scn = elf_nextscn(elf, scn); cp++) {
                if (gelf_getshdr(scn, &cp->c_shdr) == NULL) {
                        dprintf("Pbuild_file_symtab: Failed to get section "
                            "header\n");
                        goto bad; /* Failed to get section header */
                }

                if ((cp->c_data = elf_getdata(scn, NULL)) == NULL) {
                        dprintf("Pbuild_file_symtab: Failed to get section "
                            "data\n");
                        goto bad; /* Failed to get section data */
                }

                if (cp->c_shdr.sh_name >= shdata->d_size) {
                        dprintf("Pbuild_file_symtab: corrupt section name");
                        goto bad; /* Corrupt section name */
                }

                cp->c_name = (const char *)shdata->d_buf + cp->c_shdr.sh_name;
        }

        /*
         * Now iterate through the section cache in order to locate info
         * for the .symtab, .dynsym, .SUNW_ldynsym, .dynamic, .plt,
         * and .SUNW_ctf sections:
         */
        for (i = 1, cp = cache + 1; i < nshdrs; i++, cp++) {
                GElf_Shdr *shp = &cp->c_shdr;

                if (shp->sh_type == SHT_SYMTAB || shp->sh_type == SHT_DYNSYM) {
                        sym_tbl_t *symp = shp->sh_type == SHT_SYMTAB ?
                            &fptr->file_symtab : &fptr->file_dynsym;
                        /*
                         * It's possible that the we already got the symbol
                         * table from the core file itself. Either the file
                         * differs in which case our faked up elf file will
                         * only contain the dynsym (not the symtab) or the
                         * file matches in which case we'll just be replacing
                         * the symbol table we pulled out of the core file
                         * with an equivalent one. In either case, this
                         * check isn't essential, but it's a good idea.
                         */
                        if (symp->sym_data_pri == NULL) {
                                dprintf("Symbol table found for %s\n",
                                    objectfile);
                                symp->sym_data_pri = cp->c_data;
                                symp->sym_symn +=
                                    shp->sh_size / shp->sh_entsize;
                                symp->sym_strs =
                                    cache[shp->sh_link].c_data->d_buf;
                                symp->sym_strsz =
                                    cache[shp->sh_link].c_data->d_size;
                                symp->sym_hdr_pri = cp->c_shdr;
                                symp->sym_strhdr = cache[shp->sh_link].c_shdr;
                        } else {
                                dprintf("Symbol table already there for %s\n",
                                    objectfile);
                        }
                } else if (shp->sh_type == SHT_SUNW_LDYNSYM) {
                        /* .SUNW_ldynsym section is auxiliary to .dynsym */
                        if (fptr->file_dynsym.sym_data_aux == NULL) {
                                dprintf(".SUNW_ldynsym symbol table"
                                    " found for %s\n", objectfile);
                                fptr->file_dynsym.sym_data_aux = cp->c_data;
                                fptr->file_dynsym.sym_symn_aux =
                                    shp->sh_size / shp->sh_entsize;
                                fptr->file_dynsym.sym_symn +=
                                    fptr->file_dynsym.sym_symn_aux;
                                fptr->file_dynsym.sym_hdr_aux = cp->c_shdr;
                        } else {
                                dprintf(".SUNW_ldynsym symbol table already"
                                    " there for %s\n", objectfile);
                        }
                } else if (shp->sh_type == SHT_DYNAMIC) {
                        dyn = cp;
                } else if (strcmp(cp->c_name, ".plt") == 0) {
                        plt = cp;
                } else if (strcmp(cp->c_name, ".SUNW_ctf") == 0) {
                        /*
                         * Skip over bogus CTF sections so they don't come back
                         * to haunt us later.
                         */
                        if (shp->sh_link == 0 ||
                            shp->sh_link >= nshdrs ||
                            (cache[shp->sh_link].c_shdr.sh_type != SHT_DYNSYM &&
                            cache[shp->sh_link].c_shdr.sh_type != SHT_SYMTAB)) {
                                dprintf("Bad sh_link %d for "
                                    "CTF\n", shp->sh_link);
                                continue;
                        }
                        ctf = cp;
                }
        }

        /*
         * At this point, we've found all the symbol tables we're ever going
         * to find: the ones in the loop above and possibly the symtab that
         * was included in the core file. Before we perform any lookups, we
         * create sorted versions to optimize for lookups.
         */
        optimize_symtab(&fptr->file_symtab);
        optimize_symtab(&fptr->file_dynsym);

        /*
         * Fill in the base address of the text mapping for shared libraries.
         * This allows us to translate symbols before librtld_db is ready.
         */
        if (fptr->file_etype == ET_DYN) {
                fptr->file_dyn_base = fptr->file_map->map_pmap.pr_vaddr -
                    fptr->file_map->map_pmap.pr_offset;
                dprintf("setting file_dyn_base for %s to %lx\n",
                    objectfile, (long)fptr->file_dyn_base);
        }

        /*
         * Record the CTF section information in the file info structure.
         */
        if (ctf != NULL) {
                fptr->file_ctf_off = ctf->c_shdr.sh_offset;
                fptr->file_ctf_size = ctf->c_shdr.sh_size;
                if (ctf->c_shdr.sh_link != 0 &&
                    cache[ctf->c_shdr.sh_link].c_shdr.sh_type == SHT_DYNSYM)
                        fptr->file_ctf_dyn = 1;
        }

        if (fptr->file_lo == NULL)
                goto done; /* Nothing else to do if no load object info */

        /*
         * If the object is a shared library and we have a different rl_base
         * value, reset file_dyn_base according to librtld_db's information.
         */
        if (fptr->file_etype == ET_DYN &&
            fptr->file_lo->rl_base != fptr->file_dyn_base) {
                dprintf("resetting file_dyn_base for %s to %lx\n",
                    objectfile, (long)fptr->file_lo->rl_base);
                fptr->file_dyn_base = fptr->file_lo->rl_base;
        }

        /*
         * Fill in the PLT information for this file if a PLT symbol is found.
         */
        if (sym_by_name(&fptr->file_dynsym, "_PROCEDURE_LINKAGE_TABLE_", &s,
            NULL) != NULL) {
                fptr->file_plt_base = s.st_value + fptr->file_dyn_base;
                fptr->file_plt_size = (plt != NULL) ? plt->c_shdr.sh_size : 0;

                /*
                 * Bring the load object up to date; it is the only way the
                 * user has to access the PLT data. The PLT information in the
                 * rd_loadobj_t is not set in the call to map_iter() (the
                 * callback for rd_loadobj_iter) where we set file_lo.
                 */
                fptr->file_lo->rl_plt_base = fptr->file_plt_base;
                fptr->file_lo->rl_plt_size = fptr->file_plt_size;

                dprintf("PLT found at %p, size = %lu\n",
                    (void *)fptr->file_plt_base, (ulong_t)fptr->file_plt_size);
        }

        /*
         * Fill in the PLT information.
         */
        if (dyn != NULL) {
                uintptr_t dynaddr = dyn->c_shdr.sh_addr + fptr->file_dyn_base;
                size_t ndyn = dyn->c_shdr.sh_size / dyn->c_shdr.sh_entsize;
                GElf_Dyn d;

                for (i = 0; i < ndyn; i++) {
                        if (gelf_getdyn(dyn->c_data, i, &d) == NULL)
                                continue;

                        switch (d.d_tag) {
                        case DT_JMPREL:
                                dprintf("DT_JMPREL is %p\n",
                                    (void *)(uintptr_t)d.d_un.d_ptr);
                                fptr->file_jmp_rel =
                                    d.d_un.d_ptr + fptr->file_dyn_base;
                                break;
                        case DT_STRTAB:
                                dprintf("DT_STRTAB is %p\n",
                                    (void *)(uintptr_t)d.d_un.d_ptr);
                                break;
                        case DT_PLTGOT:
                                dprintf("DT_PLTGOT is %p\n",
                                    (void *)(uintptr_t)d.d_un.d_ptr);
                                break;
                        case DT_SUNW_SYMTAB:
                                dprintf("DT_SUNW_SYMTAB is %p\n",
                                    (void *)(uintptr_t)d.d_un.d_ptr);
                                break;
                        case DT_SYMTAB:
                                dprintf("DT_SYMTAB is %p\n",
                                    (void *)(uintptr_t)d.d_un.d_ptr);
                                break;
                        case DT_HASH:
                                dprintf("DT_HASH is %p\n",
                                    (void *)(uintptr_t)d.d_un.d_ptr);
                                break;
                        }
                }

                dprintf("_DYNAMIC found at %p, %lu entries, DT_JMPREL = %p\n",
                    (void *)dynaddr, (ulong_t)ndyn, (void *)fptr->file_jmp_rel);
        }

done:
        free(cache);
        return;

bad:
        free(cache);

        (void) elf_end(elf);
        fptr->file_elf = NULL;
        if (fptr->file_elfmem != NULL) {
                free(fptr->file_elfmem);
                fptr->file_elfmem = NULL;
        }
        (void) close(fptr->file_fd);
        fptr->file_fd = -1;
}

/*
 * Given a process virtual address, return the map_info_t containing it.
 * If none found, return NULL.
 */
map_info_t *
Paddr2mptr(struct ps_prochandle *P, uintptr_t addr)
{
        int lo = 0;
        int hi = P->map_count - 1;
        int mid;
        map_info_t *mp;

        while (lo <= hi) {

                mid = (lo + hi) / 2;
                mp = &P->mappings[mid];

                /* check that addr is in [vaddr, vaddr + size) */
                if ((addr - mp->map_pmap.pr_vaddr) < mp->map_pmap.pr_size)
                        return (mp);

                if (addr < mp->map_pmap.pr_vaddr)
                        hi = mid - 1;
                else
                        lo = mid + 1;
        }

        return (NULL);
}

/*
 * Return the map_info_t for the executable file.
 * If not found, return NULL.
 */
static map_info_t *
exec_map(struct ps_prochandle *P)
{
        uint_t i;
        map_info_t *mptr;
        map_info_t *mold = NULL;
        file_info_t *fptr;
        uintptr_t base;

        for (i = 0, mptr = P->mappings; i < P->map_count; i++, mptr++) {
                if (mptr->map_pmap.pr_mapname[0] == '\0')
                        continue;
                if (strcmp(mptr->map_pmap.pr_mapname, "a.out") == 0) {
                        if ((fptr = mptr->map_file) != NULL &&
                            fptr->file_lo != NULL) {
                                base = fptr->file_lo->rl_base;
                                if (base >= mptr->map_pmap.pr_vaddr &&
                                    base < mptr->map_pmap.pr_vaddr +
                                    mptr->map_pmap.pr_size)     /* text space */
                                        return (mptr);
                                mold = mptr;    /* must be the data */
                                continue;
                        }
                        /* This is a poor way to test for text space */
                        if (!(mptr->map_pmap.pr_mflags & MA_EXEC) ||
                            (mptr->map_pmap.pr_mflags & MA_WRITE)) {
                                mold = mptr;
                                continue;
                        }
                        return (mptr);
                }
        }

        return (mold);
}

/*
 * Given a shared object name, return the map_info_t for it.  If no matching
 * object is found, return NULL.  Normally, the link maps contain the full
 * object pathname, e.g. /usr/lib/libc.so.1.  We allow the object name to
 * take one of the following forms:
 *
 * 1. An exact match (i.e. a full pathname): "/usr/lib/libc.so.1"
 * 2. An exact basename match: "libc.so.1"
 * 3. An initial basename match up to a '.' suffix: "libc.so" or "libc"
 * 4. The literal string "a.out" is an alias for the executable mapping
 *
 * The third case is a convenience for callers and may not be necessary.
 *
 * As the exact same object name may be loaded on different link maps (see
 * dlmopen(3DL)), we also allow the caller to resolve the object name by
 * specifying a particular link map id.  If lmid is PR_LMID_EVERY, the
 * first matching name will be returned, regardless of the link map id.
 */
static map_info_t *
object_to_map(struct ps_prochandle *P, Lmid_t lmid, const char *objname)
{
        map_info_t *mp;
        file_info_t *fp;
        size_t objlen;
        uint_t i;

        /*
         * If we have no rtld_db, then always treat a request as one for all
         * link maps.
         */
        if (P->rap == NULL)
                lmid = PR_LMID_EVERY;

        /*
         * First pass: look for exact matches of the entire pathname or
         * basename (cases 1 and 2 above):
         */
        for (i = 0, mp = P->mappings; i < P->map_count; i++, mp++) {

                if (mp->map_pmap.pr_mapname[0] == '\0' ||
                    (fp = mp->map_file) == NULL ||
                    ((fp->file_lname == NULL) && (fp->file_rname == NULL)))
                        continue;

                if (lmid != PR_LMID_EVERY &&
                    (fp->file_lo == NULL || lmid != fp->file_lo->rl_lmident))
                        continue;

                /*
                 * If we match, return the primary text mapping; otherwise
                 * just return the mapping we matched.
                 */
                if ((fp->file_lbase && strcmp(fp->file_lbase, objname) == 0) ||
                    (fp->file_rbase && strcmp(fp->file_rbase, objname) == 0) ||
                    (fp->file_lname && strcmp(fp->file_lname, objname) == 0) ||
                    (fp->file_rname && strcmp(fp->file_rname, objname) == 0))
                        return (fp->file_map ? fp->file_map : mp);
        }

        objlen = strlen(objname);

        /*
         * Second pass: look for partial matches (case 3 above):
         */
        for (i = 0, mp = P->mappings; i < P->map_count; i++, mp++) {

                if (mp->map_pmap.pr_mapname[0] == '\0' ||
                    (fp = mp->map_file) == NULL ||
                    ((fp->file_lname == NULL) && (fp->file_rname == NULL)))
                        continue;

                if (lmid != PR_LMID_EVERY &&
                    (fp->file_lo == NULL || lmid != fp->file_lo->rl_lmident))
                        continue;

                /*
                 * If we match, return the primary text mapping; otherwise
                 * just return the mapping we matched.
                 */
                if ((fp->file_lbase != NULL) &&
                    (strncmp(fp->file_lbase, objname, objlen) == 0) &&
                    (fp->file_lbase[objlen] == '.'))
                        return (fp->file_map ? fp->file_map : mp);
                if ((fp->file_rbase != NULL) &&
                    (strncmp(fp->file_rbase, objname, objlen) == 0) &&
                    (fp->file_rbase[objlen] == '.'))
                        return (fp->file_map ? fp->file_map : mp);
        }

        /*
         * One last check: we allow "a.out" to always alias the executable,
         * assuming this name was not in use for something else.
         */
        if ((lmid == PR_LMID_EVERY || lmid == LM_ID_BASE) &&
            (strcmp(objname, "a.out") == 0))
                return (P->map_exec);

        return (NULL);
}

static map_info_t *
object_name_to_map(struct ps_prochandle *P, Lmid_t lmid, const char *name)
{
        map_info_t *mptr;

        if (!P->info_valid)
                Pupdate_maps(P);

        if (P->map_exec == NULL && ((mptr = Paddr2mptr(P,
            Pgetauxval(P, AT_ENTRY))) != NULL || (mptr = exec_map(P)) != NULL))
                P->map_exec = mptr;

        if (P->map_ldso == NULL && (mptr = Paddr2mptr(P,
            Pgetauxval(P, AT_BASE))) != NULL)
                P->map_ldso = mptr;

        if (name == PR_OBJ_EXEC)
                mptr = P->map_exec;
        else if (name == PR_OBJ_LDSO)
                mptr = P->map_ldso;
        else if (Prd_agent(P) != NULL || P->state == PS_IDLE)
                mptr = object_to_map(P, lmid, name);
        else
                mptr = NULL;

        return (mptr);
}

/*
 * When two symbols are found by address, decide which one is to be preferred.
 */
static GElf_Sym *
sym_prefer(GElf_Sym *sym1, char *name1, GElf_Sym *sym2, char *name2)
{
        /*
         * Prefer the non-NULL symbol.
         */
        if (sym1 == NULL)
                return (sym2);
        if (sym2 == NULL)
                return (sym1);

        /*
         * Defer to the sort ordering...
         */
        return (byaddr_cmp_common(sym1, name1, sym2, name2) <= 0 ? sym1 : sym2);
}

/*
 * Use a binary search to do the work of sym_by_addr().
 */
static GElf_Sym *
sym_by_addr_binary(sym_tbl_t *symtab, GElf_Addr addr, GElf_Sym *symp,
    uint_t *idp)
{
        GElf_Sym sym, osym;
        uint_t i, oid, *byaddr = symtab->sym_byaddr;
        int min, max, mid, omid, found = 0;

        if (symtab->sym_data_pri == NULL || symtab->sym_count == 0)
                return (NULL);

        min = 0;
        max = symtab->sym_count - 1;
        osym.st_value = 0;

        /*
         * We can't return when we've found a match, we have to continue
         * searching for the closest matching symbol.
         */
        while (min <= max) {
                mid = (max + min) / 2;

                i = byaddr[mid];
                (void) symtab_getsym(symtab, i, &sym);

                if (addr >= sym.st_value &&
                    addr < sym.st_value + sym.st_size &&
                    (!found || sym.st_value > osym.st_value)) {
                        osym = sym;
                        omid = mid;
                        oid = i;
                        found = 1;
                }

                if (addr < sym.st_value)
                        max = mid - 1;
                else
                        min = mid + 1;
        }

        if (!found)
                return (NULL);

        /*
         * There may be many symbols with identical values so we walk
         * backward in the byaddr table to find the best match.
         */
        do {
                sym = osym;
                i = oid;

                if (omid == 0)
                        break;

                oid = byaddr[--omid];
                (void) symtab_getsym(symtab, oid, &osym);
        } while (addr >= osym.st_value &&
            addr < sym.st_value + osym.st_size &&
            osym.st_value == sym.st_value);

        *symp = sym;
        if (idp != NULL)
                *idp = i;
        return (symp);
}

/*
 * Use a linear search to do the work of sym_by_addr().
 */
static GElf_Sym *
sym_by_addr_linear(sym_tbl_t *symtab, GElf_Addr addr, GElf_Sym *symbolp,
    uint_t *idp)
{
        size_t symn = symtab->sym_symn;
        char *strs = symtab->sym_strs;
        GElf_Sym sym, *symp = NULL;
        GElf_Sym osym, *osymp = NULL;
        int i, id;

        if (symtab->sym_data_pri == NULL || symn == 0 || strs == NULL)
                return (NULL);

        for (i = 0; i < symn; i++) {
                if ((symp = symtab_getsym(symtab, i, &sym)) != NULL) {
                        if (addr >= sym.st_value &&
                            addr < sym.st_value + sym.st_size) {
                                if (osymp)
                                        symp = sym_prefer(
                                            symp, strs + symp->st_name,
                                            osymp, strs + osymp->st_name);
                                if (symp != osymp) {
                                        osym = sym;
                                        osymp = &osym;
                                        id = i;
                                }
                        }
                }
        }
        if (osymp) {
                *symbolp = osym;
                if (idp)
                        *idp = id;
                return (symbolp);
        }
        return (NULL);
}

/*
 * Look up a symbol by address in the specified symbol table.
 * Adjustment to 'addr' must already have been made for the
 * offset of the symbol if this is a dynamic library symbol table.
 *
 * Use a linear or a binary search depending on whether or not we
 * chose to sort the table in optimize_symtab().
 */
static GElf_Sym *
sym_by_addr(sym_tbl_t *symtab, GElf_Addr addr, GElf_Sym *symp, uint_t *idp)
{
        if (_libproc_no_qsort) {
                return (sym_by_addr_linear(symtab, addr, symp, idp));
        } else {
                return (sym_by_addr_binary(symtab, addr, symp, idp));
        }
}

/*
 * Use a binary search to do the work of sym_by_name().
 */
static GElf_Sym *
sym_by_name_binary(sym_tbl_t *symtab, const char *name, GElf_Sym *symp,
    uint_t *idp)
{
        char *strs = symtab->sym_strs;
        uint_t i, *byname = symtab->sym_byname;
        int min, mid, max, cmp;

        if (symtab->sym_data_pri == NULL || strs == NULL ||
            symtab->sym_count == 0)
                return (NULL);

        min = 0;
        max = symtab->sym_count - 1;

        while (min <= max) {
                mid = (max + min) / 2;

                i = byname[mid];
                (void) symtab_getsym(symtab, i, symp);

                if ((cmp = strcmp(name, strs + symp->st_name)) == 0) {
                        if (idp != NULL)
                                *idp = i;
                        return (symp);
                }

                if (cmp < 0)
                        max = mid - 1;
                else
                        min = mid + 1;
        }

        return (NULL);
}

/*
 * Use a linear search to do the work of sym_by_name().
 */
static GElf_Sym *
sym_by_name_linear(sym_tbl_t *symtab, const char *name, GElf_Sym *symp,
    uint_t *idp)
{
        size_t symn = symtab->sym_symn;
        char *strs = symtab->sym_strs;
        int i;

        if (symtab->sym_data_pri == NULL || symn == 0 || strs == NULL)
                return (NULL);

        for (i = 0; i < symn; i++) {
                if (symtab_getsym(symtab, i, symp) &&
                    strcmp(name, strs + symp->st_name) == 0) {
                        if (idp)
                                *idp = i;
                        return (symp);
                }
        }

        return (NULL);
}

/*
 * Look up a symbol by name in the specified symbol table.
 *
 * Use a linear or a binary search depending on whether or not we
 * chose to sort the table in optimize_symtab().
 */
static GElf_Sym *
sym_by_name(sym_tbl_t *symtab, const char *name, GElf_Sym *symp, uint_t *idp)
{
        if (_libproc_no_qsort) {
                return (sym_by_name_linear(symtab, name, symp, idp));
        } else {
                return (sym_by_name_binary(symtab, name, symp, idp));
        }
}

/*
 * Search the process symbol tables looking for a symbol whose
 * value to value+size contain the address specified by addr.
 * Return values are:
 *      sym_name_buffer containing the symbol name
 *      GElf_Sym symbol table entry
 *      prsyminfo_t ancillary symbol information
 * Returns 0 on success, -1 on failure.
 */
static int
i_Pxlookup_by_addr(
        struct ps_prochandle *P,
        int lmresolve,                  /* use resolve linker object names */
        uintptr_t addr,                 /* process address being sought */
        char *sym_name_buffer,          /* buffer for the symbol name */
        size_t bufsize,                 /* size of sym_name_buffer */
        GElf_Sym *symbolp,              /* returned symbol table entry */
        prsyminfo_t *sip)               /* returned symbol info */
{
        GElf_Sym        *symp;
        char            *name;
        GElf_Sym        sym1, *sym1p = NULL;
        GElf_Sym        sym2, *sym2p = NULL;
        char            *name1 = NULL;
        char            *name2 = NULL;
        uint_t          i1;
        uint_t          i2;
        map_info_t      *mptr;
        file_info_t     *fptr;

        (void) Prd_agent(P);

        if ((mptr = Paddr2mptr(P, addr)) == NULL ||     /* no such address */
            (fptr = build_map_symtab(P, mptr)) == NULL || /* no mapped file */
            fptr->file_elf == NULL)                     /* not an ELF file */
                return (-1);

        /*
         * Adjust the address by the load object base address in
         * case the address turns out to be in a shared library.
         */
        addr -= fptr->file_dyn_base;

        /*
         * Search both symbol tables, symtab first, then dynsym.
         */
        if ((sym1p = sym_by_addr(&fptr->file_symtab, addr, &sym1, &i1)) != NULL)
                name1 = fptr->file_symtab.sym_strs + sym1.st_name;
        if ((sym2p = sym_by_addr(&fptr->file_dynsym, addr, &sym2, &i2)) != NULL)
                name2 = fptr->file_dynsym.sym_strs + sym2.st_name;

        if ((symp = sym_prefer(sym1p, name1, sym2p, name2)) == NULL)
                return (-1);

        name = (symp == sym1p) ? name1 : name2;
        if (bufsize > 0) {
                (void) strncpy(sym_name_buffer, name, bufsize);
                sym_name_buffer[bufsize - 1] = '\0';
        }

        *symbolp = *symp;
        if (sip != NULL) {
                sip->prs_name = bufsize == 0 ? NULL : sym_name_buffer;
                if (lmresolve && (fptr->file_rname != NULL))
                        sip->prs_object = fptr->file_rbase;
                else
                        sip->prs_object = fptr->file_lbase;
                sip->prs_id = (symp == sym1p) ? i1 : i2;
                sip->prs_table = (symp == sym1p) ? PR_SYMTAB : PR_DYNSYM;
                sip->prs_lmid = (fptr->file_lo == NULL) ? LM_ID_BASE :
                    fptr->file_lo->rl_lmident;
        }

        if (GELF_ST_TYPE(symbolp->st_info) != STT_TLS)
                symbolp->st_value += fptr->file_dyn_base;

        return (0);
}

int
Pxlookup_by_addr(struct ps_prochandle *P, uintptr_t addr, char *buf,
    size_t bufsize, GElf_Sym *symp, prsyminfo_t *sip)
{
        return (i_Pxlookup_by_addr(P, B_FALSE, addr, buf, bufsize, symp, sip));
}

int
Pxlookup_by_addr_resolved(struct ps_prochandle *P, uintptr_t addr, char *buf,
    size_t bufsize, GElf_Sym *symp, prsyminfo_t *sip)
{
        return (i_Pxlookup_by_addr(P, B_TRUE, addr, buf, bufsize, symp, sip));
}

int
Plookup_by_addr(struct ps_prochandle *P, uintptr_t addr, char *buf,
    size_t size, GElf_Sym *symp)
{
        return (i_Pxlookup_by_addr(P, B_FALSE, addr, buf, size, symp, NULL));
}

/*
 * Search the process symbol tables looking for a symbol whose name matches the
 * specified name and whose object and link map optionally match the specified
 * parameters.  On success, the function returns 0 and fills in the GElf_Sym
 * symbol table entry.  On failure, -1 is returned.
 */
int
Pxlookup_by_name(
        struct ps_prochandle *P,
        Lmid_t lmid,                    /* link map to match, or -1 for any */
        const char *oname,              /* load object name */
        const char *sname,              /* symbol name */
        GElf_Sym *symp,                 /* returned symbol table entry */
        prsyminfo_t *sip)               /* returned symbol info */
{
        map_info_t *mptr;
        file_info_t *fptr;
        int cnt;

        GElf_Sym sym;
        prsyminfo_t si;
        int rv = -1;
        uint_t id;

        if (oname == PR_OBJ_EVERY) {
                /* create all the file_info_t's for all the mappings */
                (void) Prd_agent(P);
                cnt = P->num_files;
                fptr = list_next(&P->file_head);
        } else {
                cnt = 1;
                if ((mptr = object_name_to_map(P, lmid, oname)) == NULL ||
                    (fptr = build_map_symtab(P, mptr)) == NULL)
                        return (-1);
        }

        /*
         * Iterate through the loaded object files and look for the symbol
         * name in the .symtab and .dynsym of each.  If we encounter a match
         * with SHN_UNDEF, keep looking in hopes of finding a better match.
         * This means that a name such as "puts" will match the puts function
         * in libc instead of matching the puts PLT entry in the a.out file.
         */
        for (; cnt > 0; cnt--, fptr = list_next(fptr)) {
                Pbuild_file_symtab(P, fptr);

                if (fptr->file_elf == NULL)
                        continue;

                if (lmid != PR_LMID_EVERY && fptr->file_lo != NULL &&
                    lmid != fptr->file_lo->rl_lmident)
                        continue;

                if (fptr->file_symtab.sym_data_pri != NULL &&
                    sym_by_name(&fptr->file_symtab, sname, symp, &id)) {
                        if (sip != NULL) {
                                sip->prs_id = id;
                                sip->prs_table = PR_SYMTAB;
                                sip->prs_object = oname;
                                sip->prs_name = sname;
                                sip->prs_lmid = fptr->file_lo == NULL ?
                                    LM_ID_BASE : fptr->file_lo->rl_lmident;
                        }
                } else if (fptr->file_dynsym.sym_data_pri != NULL &&
                    sym_by_name(&fptr->file_dynsym, sname, symp, &id)) {
                        if (sip != NULL) {
                                sip->prs_id = id;
                                sip->prs_table = PR_DYNSYM;
                                sip->prs_object = oname;
                                sip->prs_name = sname;
                                sip->prs_lmid = fptr->file_lo == NULL ?
                                    LM_ID_BASE : fptr->file_lo->rl_lmident;
                        }
                } else {
                        continue;
                }

                if (GELF_ST_TYPE(symp->st_info) != STT_TLS)
                        symp->st_value += fptr->file_dyn_base;

                if (symp->st_shndx != SHN_UNDEF)
                        return (0);

                if (rv != 0) {
                        if (sip != NULL)
                                si = *sip;
                        sym = *symp;
                        rv = 0;
                }
        }

        if (rv == 0) {
                if (sip != NULL)
                        *sip = si;
                *symp = sym;
        }

        return (rv);
}

/*
 * Search the process symbol tables looking for a symbol whose name matches the
 * specified name, but without any restriction on the link map id.
 */
int
Plookup_by_name(struct ps_prochandle *P, const char *object,
    const char *symbol, GElf_Sym *symp)
{
        return (Pxlookup_by_name(P, PR_LMID_EVERY, object, symbol, symp, NULL));
}

/*
 * Iterate over the process's address space mappings.
 */
static int
i_Pmapping_iter(struct ps_prochandle *P, boolean_t lmresolve,
    proc_map_f *func, void *cd)
{
        map_info_t *mptr;
        file_info_t *fptr;
        char *object_name;
        int rc = 0;
        int i;

        /* create all the file_info_t's for all the mappings */
        (void) Prd_agent(P);

        for (i = 0, mptr = P->mappings; i < P->map_count; i++, mptr++) {
                if ((fptr = mptr->map_file) == NULL)
                        object_name = NULL;
                else if (lmresolve && (fptr->file_rname != NULL))
                        object_name = fptr->file_rname;
                else
                        object_name = fptr->file_lname;
                if ((rc = func(cd, &mptr->map_pmap, object_name)) != 0)
                        return (rc);
        }
        return (0);
}

int
Pmapping_iter(struct ps_prochandle *P, proc_map_f *func, void *cd)
{
        return (i_Pmapping_iter(P, B_FALSE, func, cd));
}

int
Pmapping_iter_resolved(struct ps_prochandle *P, proc_map_f *func, void *cd)
{
        return (i_Pmapping_iter(P, B_TRUE, func, cd));
}

/*
 * Iterate over the process's mapped objects.
 */
static int
i_Pobject_iter(struct ps_prochandle *P, boolean_t lmresolve,
    proc_map_f *func, void *cd)
{
        map_info_t *mptr;
        file_info_t *fptr;
        uint_t cnt;
        int rc = 0;

        (void) Prd_agent(P); /* create file_info_t's for all the mappings */
        Pupdate_maps(P);

        for (cnt = P->num_files, fptr = list_next(&P->file_head);
            cnt; cnt--, fptr = list_next(fptr)) {
                const char *lname;

                if (lmresolve && (fptr->file_rname != NULL))
                        lname = fptr->file_rname;
                else if (fptr->file_lname != NULL)
                        lname = fptr->file_lname;
                else
                        lname = "";

                if ((mptr = fptr->file_map) == NULL)
                        continue;

                if ((rc = func(cd, &mptr->map_pmap, lname)) != 0)
                        return (rc);

                if (!P->info_valid)
                        Pupdate_maps(P);
        }
        return (0);
}

int
Pobject_iter(struct ps_prochandle *P, proc_map_f *func, void *cd)
{
        return (i_Pobject_iter(P, B_FALSE, func, cd));
}

int
Pobject_iter_resolved(struct ps_prochandle *P, proc_map_f *func, void *cd)
{
        return (i_Pobject_iter(P, B_TRUE, func, cd));
}

static char *
i_Pobjname(struct ps_prochandle *P, boolean_t lmresolve, uintptr_t addr,
    char *buffer, size_t bufsize)
{
        map_info_t *mptr;
        file_info_t *fptr;

        /* create all the file_info_t's for all the mappings */
        (void) Prd_agent(P);

        if ((mptr = Paddr2mptr(P, addr)) == NULL)
                return (NULL);

        if (!lmresolve) {
                if (((fptr = mptr->map_file) == NULL) ||
                    (fptr->file_lname == NULL))
                        return (NULL);
                (void) strlcpy(buffer, fptr->file_lname, bufsize);
                return (buffer);
        }

        /* Check for a cached copy of the resolved path */
        if (Pfindmap(P, mptr, buffer, bufsize) != NULL)
                return (buffer);

        return (NULL);
}

/*
 * Given a virtual address, return the name of the underlying
 * mapped object (file) as provided by the dynamic linker.
 * Return NULL if we can't find any name information for the object.
 */
char *
Pobjname(struct ps_prochandle *P, uintptr_t addr,
    char *buffer, size_t bufsize)
{
        return (i_Pobjname(P, B_FALSE, addr, buffer, bufsize));
}

/*
 * Given a virtual address, try to return a filesystem path to the
 * underlying mapped object (file).  If we're in the global zone,
 * this path could resolve to an object in another zone.  If we're
 * unable return a valid filesystem path, we'll fall back to providing
 * the mapped object (file) name provided by the dynamic linker in
 * the target process (ie, the object reported by Pobjname()).
 */
char *
Pobjname_resolved(struct ps_prochandle *P, uintptr_t addr,
    char *buffer, size_t bufsize)
{
        return (i_Pobjname(P, B_TRUE, addr, buffer, bufsize));
}

/*
 * Given a virtual address, return the link map id of the underlying mapped
 * object (file), as provided by the dynamic linker.  Return -1 on failure.
 */
int
Plmid(struct ps_prochandle *P, uintptr_t addr, Lmid_t *lmidp)
{
        map_info_t *mptr;
        file_info_t *fptr;

        /* create all the file_info_t's for all the mappings */
        (void) Prd_agent(P);

        if ((mptr = Paddr2mptr(P, addr)) != NULL &&
            (fptr = mptr->map_file) != NULL && fptr->file_lo != NULL) {
                *lmidp = fptr->file_lo->rl_lmident;
                return (0);
        }

        return (-1);
}

/*
 * Given an object name and optional lmid, iterate over the object's symbols.
 * If which == PR_SYMTAB, search the normal symbol table.
 * If which == PR_DYNSYM, search the dynamic symbol table.
 */
static int
Psymbol_iter_com(struct ps_prochandle *P, Lmid_t lmid, const char *object_name,
    int which, int mask, pr_order_t order, proc_xsym_f *func, void *cd)
{
#if STT_NUM != (STT_TLS + 1)
#error "STT_NUM has grown. update Psymbol_iter_com()"
#endif

        GElf_Sym sym;
        GElf_Shdr shdr;
        map_info_t *mptr;
        file_info_t *fptr;
        sym_tbl_t *symtab;
        size_t symn;
        const char *strs;
        size_t strsz;
        prsyminfo_t si;
        int rv;
        uint_t *map, i, count, ndx;

        if ((mptr = object_name_to_map(P, lmid, object_name)) == NULL)
                return (-1);

        if ((fptr = build_map_symtab(P, mptr)) == NULL || /* no mapped file */
            fptr->file_elf == NULL)                     /* not an ELF file */
                return (-1);

        /*
         * Search the specified symbol table.
         */
        switch (which) {
        case PR_SYMTAB:
                symtab = &fptr->file_symtab;
                si.prs_table = PR_SYMTAB;
                break;
        case PR_DYNSYM:
                symtab = &fptr->file_dynsym;
                si.prs_table = PR_DYNSYM;
                break;
        default:
                return (-1);
        }

        si.prs_object = object_name;
        si.prs_lmid = fptr->file_lo == NULL ?
            LM_ID_BASE : fptr->file_lo->rl_lmident;

        symn = symtab->sym_symn;
        strs = symtab->sym_strs;
        strsz = symtab->sym_strsz;

        switch (order) {
        case PRO_NATURAL:
                map = NULL;
                count = symn;
                break;
        case PRO_BYNAME:
                map = symtab->sym_byname;
                count = symtab->sym_count;
                break;
        case PRO_BYADDR:
                map = symtab->sym_byaddr;
                count = symtab->sym_count;
                break;
        default:
                return (-1);
        }

        if (symtab->sym_data_pri == NULL || strs == NULL || count == 0)
                return (-1);

        rv = 0;

        for (i = 0; i < count; i++) {
                ndx = map == NULL ? i : map[i];
                if (symtab_getsym(symtab, ndx, &sym) != NULL) {
                        uint_t s_bind, s_type, type;

                        if (sym.st_name >= strsz)       /* invalid st_name */
                                continue;

                        s_bind = GELF_ST_BIND(sym.st_info);
                        s_type = GELF_ST_TYPE(sym.st_info);

                        /*
                         * In case you haven't already guessed, this relies on
                         * the bitmask used in <libproc.h> for encoding symbol
                         * type and binding matching the order of STB and STT
                         * constants in <sys/elf.h>.  Changes to ELF must
                         * maintain binary compatibility, so I think this is
                         * reasonably fair game.
                         */
                        if (s_bind < STB_NUM && s_type < STT_NUM) {
                                type = (1 << (s_type + 8)) | (1 << s_bind);
                                if ((type & ~mask) != 0)
                                        continue;
                        } else
                                continue; /* Invalid type or binding */

                        if (GELF_ST_TYPE(sym.st_info) != STT_TLS)
                                sym.st_value += fptr->file_dyn_base;

                        si.prs_name = strs + sym.st_name;

                        /*
                         * If symbol's type is STT_SECTION, then try to lookup
                         * the name of the corresponding section.
                         */
                        if (GELF_ST_TYPE(sym.st_info) == STT_SECTION &&
                            fptr->file_shstrs != NULL &&
                            gelf_getshdr(elf_getscn(fptr->file_elf,
                            sym.st_shndx), &shdr) != NULL &&
                            shdr.sh_name != 0 &&
                            shdr.sh_name < fptr->file_shstrsz)
                                si.prs_name = fptr->file_shstrs + shdr.sh_name;

                        si.prs_id = ndx;
                        if ((rv = func(cd, &sym, si.prs_name, &si)) != 0)
                                break;
                }
        }

        return (rv);
}

int
Pxsymbol_iter(struct ps_prochandle *P, Lmid_t lmid, const char *object_name,
    int which, int mask, proc_xsym_f *func, void *cd)
{
        return (Psymbol_iter_com(P, lmid, object_name, which, mask,
            PRO_NATURAL, func, cd));
}

int
Psymbol_iter_by_lmid(struct ps_prochandle *P, Lmid_t lmid,
    const char *object_name, int which, int mask, proc_sym_f *func, void *cd)
{
        return (Psymbol_iter_com(P, lmid, object_name, which, mask,
            PRO_NATURAL, (proc_xsym_f *)func, cd));
}

int
Psymbol_iter(struct ps_prochandle *P,
    const char *object_name, int which, int mask, proc_sym_f *func, void *cd)
{
        return (Psymbol_iter_com(P, PR_LMID_EVERY, object_name, which, mask,
            PRO_NATURAL, (proc_xsym_f *)func, cd));
}

int
Psymbol_iter_by_addr(struct ps_prochandle *P,
    const char *object_name, int which, int mask, proc_sym_f *func, void *cd)
{
        return (Psymbol_iter_com(P, PR_LMID_EVERY, object_name, which, mask,
            PRO_BYADDR, (proc_xsym_f *)func, cd));
}

int
Psymbol_iter_by_name(struct ps_prochandle *P,
    const char *object_name, int which, int mask, proc_sym_f *func, void *cd)
{
        return (Psymbol_iter_com(P, PR_LMID_EVERY, object_name, which, mask,
            PRO_BYNAME, (proc_xsym_f *)func, cd));
}

/*
 * Get the platform string.
 */
char *
Pplatform(struct ps_prochandle *P, char *s, size_t n)
{
        return (P->ops.pop_platform(P, s, n, P->data));
}

/*
 * Get the uname(2) information.
 */
int
Puname(struct ps_prochandle *P, struct utsname *u)
{
        return (P->ops.pop_uname(P, u, P->data));
}

/*
 * Called from Pcreate(), Pgrab(), and Pfgrab_core() to initialize
 * the symbol table heads in the new ps_prochandle.
 */
void
Pinitsym(struct ps_prochandle *P)
{
        P->num_files = 0;
        list_link(&P->file_head, NULL);
}

/*
 * Called from Prelease() to destroy the symbol tables.
 * Must be called by the client after an exec() in the victim process.
 */
void
Preset_maps(struct ps_prochandle *P)
{
        int i;

        if (P->rap != NULL) {
                rd_delete(P->rap);
                P->rap = NULL;
        }

        if (P->execname != NULL) {
                free(P->execname);
                P->execname = NULL;
        }

        if (P->auxv != NULL) {
                free(P->auxv);
                P->auxv = NULL;
                P->nauxv = 0;
        }

        for (i = 0; i < P->map_count; i++)
                map_info_free(P, &P->mappings[i]);

        if (P->mappings != NULL) {
                free(P->mappings);
                P->mappings = NULL;
        }
        P->map_count = P->map_alloc = 0;

        P->info_valid = 0;
}

typedef struct getenv_data {
        char *buf;
        size_t bufsize;
        const char *search;
        size_t searchlen;
} getenv_data_t;

/*ARGSUSED*/
static int
getenv_func(void *data, struct ps_prochandle *P, uintptr_t addr,
    const char *nameval)
{
        getenv_data_t *d = data;
        size_t len;

        if (nameval == NULL)
                return (0);

        if (d->searchlen < strlen(nameval) &&
            strncmp(nameval, d->search, d->searchlen) == 0 &&
            nameval[d->searchlen] == '=') {
                len = MIN(strlen(nameval), d->bufsize - 1);
                (void) strncpy(d->buf, nameval, len);
                d->buf[len] = '\0';
                return (1);
        }

        return (0);
}

char *
Pgetenv(struct ps_prochandle *P, const char *name, char *buf, size_t buflen)
{
        getenv_data_t d;

        d.buf = buf;
        d.bufsize = buflen;
        d.search = name;
        d.searchlen = strlen(name);

        if (Penv_iter(P, getenv_func, &d) == 1) {
                char *equals = strchr(d.buf, '=');

                if (equals != NULL) {
                        (void) memmove(d.buf, equals + 1,
                            d.buf + buflen - equals - 1);
                        d.buf[d.buf + buflen - equals] = '\0';

                        return (buf);
                }
        }

        return (NULL);
}

/* number of argument or environment pointers to read all at once */
#define NARG    100

int
Penv_iter(struct ps_prochandle *P, proc_env_f *func, void *data)
{
        const psinfo_t *psp;
        uintptr_t envpoff;
        GElf_Sym sym;
        int ret;
        char *buf, *nameval;
        size_t buflen;

        int nenv = NARG;
        long envp[NARG];

        /*
         * Attempt to find the "_environ" variable in the process.
         * Failing that, use the original value provided by Ppsinfo().
         */
        if ((psp = Ppsinfo(P)) == NULL)
                return (-1);

        envpoff = psp->pr_envp; /* Default if no _environ found */

        if (Plookup_by_name(P, PR_OBJ_EXEC, "_environ", &sym) == 0) {
                if (P->status.pr_dmodel == PR_MODEL_NATIVE) {
                        if (Pread(P, &envpoff, sizeof (envpoff),
                            sym.st_value) != sizeof (envpoff))
                                envpoff = psp->pr_envp;
                } else if (P->status.pr_dmodel == PR_MODEL_ILP32) {
                        uint32_t envpoff32;

                        if (Pread(P, &envpoff32, sizeof (envpoff32),
                            sym.st_value) != sizeof (envpoff32))
                                envpoff = psp->pr_envp;
                        else
                                envpoff = envpoff32;
                }
        }

        buflen = 128;
        buf = malloc(buflen);

        ret = 0;
        for (;;) {
                uintptr_t envoff;

                if (nenv == NARG) {
                        (void) memset(envp, 0, sizeof (envp));
                        if (P->status.pr_dmodel == PR_MODEL_NATIVE) {
                                if (Pread(P, envp,
                                    sizeof (envp), envpoff) <= 0) {
                                        ret = -1;
                                        break;
                                }
                        } else if (P->status.pr_dmodel == PR_MODEL_ILP32) {
                                uint32_t e32[NARG];
                                int i;

                                (void) memset(e32, 0, sizeof (e32));
                                if (Pread(P, e32, sizeof (e32), envpoff) <= 0) {
                                        ret = -1;
                                        break;
                                }
                                for (i = 0; i < NARG; i++)
                                        envp[i] = e32[i];
                        }
                        nenv = 0;
                }

                if ((envoff = envp[nenv++]) == (uintptr_t)NULL)
                        break;

                /*
                 * Attempt to read the string from the process.
                 */
again:
                ret = Pread_string(P, buf, buflen, envoff);

                if (ret <= 0) {
                        nameval = NULL;
                } else if (ret == buflen - 1) {
                        free(buf);
                        /*
                         * Bail if we have a corrupted environment
                         */
                        if (buflen >= ARG_MAX)
                                return (-1);
                        buflen *= 2;
                        buf = malloc(buflen);
                        goto again;
                } else {
                        nameval = buf;
                }

                if ((ret = func(data, P, envoff, nameval)) != 0)
                        break;

                envpoff += (P->status.pr_dmodel == PR_MODEL_LP64)? 8 : 4;
        }

        free(buf);

        return (ret);
}