dmake: do not set MAKEFLAGS=k

[unleashed/tickless.git] / usr / src / lib / libdtrace / common / dt_pid.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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
 */

#include <assert.h>
#include <strings.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <alloca.h>
#include <libgen.h>
#include <stddef.h>
#include <sys/sysmacros.h>

#include <dt_impl.h>
#include <dt_program.h>
#include <dt_pid.h>
#include <dt_string.h>
#include <dt_module.h>

typedef struct dt_pid_probe {
        dtrace_hdl_t *dpp_dtp;
        dt_pcb_t *dpp_pcb;
        dt_proc_t *dpp_dpr;
        struct ps_prochandle *dpp_pr;
        const char *dpp_mod;
        char *dpp_func;
        const char *dpp_name;
        const char *dpp_obj;
        uintptr_t dpp_pc;
        size_t dpp_size;
        Lmid_t dpp_lmid;
        uint_t dpp_nmatches;
        uint64_t dpp_stret[4];
        GElf_Sym dpp_last;
        uint_t dpp_last_taken;
} dt_pid_probe_t;

/*
 * Compose the lmid and object name into the canonical representation. We
 * omit the lmid for the default link map for convenience.
 */
static void
dt_pid_objname(char *buf, size_t len, Lmid_t lmid, const char *obj)
{
        if (lmid == LM_ID_BASE)
                (void) strncpy(buf, obj, len);
        else
                (void) snprintf(buf, len, "LM%lx`%s", lmid, obj);
}

static int
dt_pid_error(dtrace_hdl_t *dtp, dt_pcb_t *pcb, dt_proc_t *dpr,
    fasttrap_probe_spec_t *ftp, dt_errtag_t tag, const char *fmt, ...)
{
        va_list ap;
        int len;

        if (ftp != NULL)
                dt_free(dtp, ftp);

        va_start(ap, fmt);
        if (pcb == NULL) {
                assert(dpr != NULL);
                len = vsnprintf(dpr->dpr_errmsg, sizeof (dpr->dpr_errmsg),
                    fmt, ap);
                assert(len >= 2);
                if (dpr->dpr_errmsg[len - 2] == '\n')
                        dpr->dpr_errmsg[len - 2] = '\0';
        } else {
                dt_set_errmsg(dtp, dt_errtag(tag), pcb->pcb_region,
                    pcb->pcb_filetag, pcb->pcb_fileptr ? yylineno : 0, fmt, ap);
        }
        va_end(ap);

        return (1);
}

static int
dt_pid_per_sym(dt_pid_probe_t *pp, const GElf_Sym *symp, const char *func)
{
        dtrace_hdl_t *dtp = pp->dpp_dtp;
        dt_pcb_t *pcb = pp->dpp_pcb;
        dt_proc_t *dpr = pp->dpp_dpr;
        fasttrap_probe_spec_t *ftp;
        uint64_t off;
        char *end;
        uint_t nmatches = 0;
        ulong_t sz;
        int glob, err;
        int isdash = strcmp("-", func) == 0;
        pid_t pid;

        pid = Pstatus(pp->dpp_pr)->pr_pid;

        dt_dprintf("creating probe pid%d:%s:%s:%s\n", (int)pid, pp->dpp_obj,
            func, pp->dpp_name);

        sz = sizeof (fasttrap_probe_spec_t) + (isdash ? 4 :
            (symp->st_size - 1) * sizeof (ftp->ftps_offs[0]));

        if ((ftp = dt_alloc(dtp, sz)) == NULL) {
                dt_dprintf("proc_per_sym: dt_alloc(%lu) failed\n", sz);
                return (1); /* errno is set for us */
        }

        ftp->ftps_pid = pid;
        (void) strncpy(ftp->ftps_func, func, sizeof (ftp->ftps_func));

        dt_pid_objname(ftp->ftps_mod, sizeof (ftp->ftps_mod), pp->dpp_lmid,
            pp->dpp_obj);

        if (!isdash && gmatch("return", pp->dpp_name)) {
                if (dt_pid_create_return_probe(pp->dpp_pr, dtp, ftp, symp,
                    pp->dpp_stret) < 0) {
                        return (dt_pid_error(dtp, pcb, dpr, ftp,
                            D_PROC_CREATEFAIL, "failed to create return probe "
                            "for '%s': %s", func,
                            dtrace_errmsg(dtp, dtrace_errno(dtp))));
                }

                nmatches++;
        }

        if (!isdash && gmatch("entry", pp->dpp_name)) {
                if (dt_pid_create_entry_probe(pp->dpp_pr, dtp, ftp, symp) < 0) {
                        return (dt_pid_error(dtp, pcb, dpr, ftp,
                            D_PROC_CREATEFAIL, "failed to create entry probe "
                            "for '%s': %s", func,
                            dtrace_errmsg(dtp, dtrace_errno(dtp))));
                }

                nmatches++;
        }

        glob = strisglob(pp->dpp_name);
        if (!glob && nmatches == 0) {
                off = strtoull(pp->dpp_name, &end, 16);
                if (*end != '\0') {
                        return (dt_pid_error(dtp, pcb, dpr, ftp, D_PROC_NAME,
                            "'%s' is an invalid probe name", pp->dpp_name));
                }

                if (off >= symp->st_size) {
                        return (dt_pid_error(dtp, pcb, dpr, ftp, D_PROC_OFF,
                            "offset 0x%llx outside of function '%s'",
                            (u_longlong_t)off, func));
                }

                err = dt_pid_create_offset_probe(pp->dpp_pr, pp->dpp_dtp, ftp,
                    symp, off);

                if (err == DT_PROC_ERR) {
                        return (dt_pid_error(dtp, pcb, dpr, ftp,
                            D_PROC_CREATEFAIL, "failed to create probe at "
                            "'%s+0x%llx': %s", func, (u_longlong_t)off,
                            dtrace_errmsg(dtp, dtrace_errno(dtp))));
                }

                if (err == DT_PROC_ALIGN) {
                        return (dt_pid_error(dtp, pcb, dpr, ftp, D_PROC_ALIGN,
                            "offset 0x%llx is not aligned on an instruction",
                            (u_longlong_t)off));
                }

                nmatches++;

        } else if (glob && !isdash) {
                if (dt_pid_create_glob_offset_probes(pp->dpp_pr,
                    pp->dpp_dtp, ftp, symp, pp->dpp_name) < 0) {
                        return (dt_pid_error(dtp, pcb, dpr, ftp,
                            D_PROC_CREATEFAIL,
                            "failed to create offset probes in '%s': %s", func,
                            dtrace_errmsg(dtp, dtrace_errno(dtp))));
                }

                nmatches++;
        }

        pp->dpp_nmatches += nmatches;

        dt_free(dtp, ftp);

        return (0);
}

static int
dt_pid_sym_filt(void *arg, const GElf_Sym *symp, const char *func)
{
        dt_pid_probe_t *pp = arg;

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

        if (symp->st_size == 0) {
                dt_dprintf("st_size of %s is zero\n", func);
                return (0);
        }

        if (pp->dpp_last_taken == 0 ||
            symp->st_value != pp->dpp_last.st_value ||
            symp->st_size != pp->dpp_last.st_size) {
                /*
                 * Due to 4524008, _init and _fini may have a bloated st_size.
                 * While this bug has been fixed for a while, old binaries
                 * may exist that still exhibit this problem. As a result, we
                 * don't match _init and _fini though we allow users to
                 * specify them explicitly.
                 */
                if (strcmp(func, "_init") == 0 || strcmp(func, "_fini") == 0)
                        return (0);

                if ((pp->dpp_last_taken = gmatch(func, pp->dpp_func)) != 0) {
                        pp->dpp_last = *symp;
                        return (dt_pid_per_sym(pp, symp, func));
                }
        }

        return (0);
}

static int
dt_pid_per_mod(void *arg, const prmap_t *pmp, const char *obj)
{
        dt_pid_probe_t *pp = arg;
        dtrace_hdl_t *dtp = pp->dpp_dtp;
        dt_pcb_t *pcb = pp->dpp_pcb;
        dt_proc_t *dpr = pp->dpp_dpr;
        GElf_Sym sym;

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

        (void) Plmid(pp->dpp_pr, pmp->pr_vaddr, &pp->dpp_lmid);

        if ((pp->dpp_obj = strrchr(obj, '/')) == NULL)
                pp->dpp_obj = obj;
        else
                pp->dpp_obj++;

        if (Pxlookup_by_name(pp->dpp_pr, pp->dpp_lmid, obj, ".stret1", &sym,
            NULL) == 0)
                pp->dpp_stret[0] = sym.st_value;
        else
                pp->dpp_stret[0] = 0;

        if (Pxlookup_by_name(pp->dpp_pr, pp->dpp_lmid, obj, ".stret2", &sym,
            NULL) == 0)
                pp->dpp_stret[1] = sym.st_value;
        else
                pp->dpp_stret[1] = 0;

        if (Pxlookup_by_name(pp->dpp_pr, pp->dpp_lmid, obj, ".stret4", &sym,
            NULL) == 0)
                pp->dpp_stret[2] = sym.st_value;
        else
                pp->dpp_stret[2] = 0;

        if (Pxlookup_by_name(pp->dpp_pr, pp->dpp_lmid, obj, ".stret8", &sym,
            NULL) == 0)
                pp->dpp_stret[3] = sym.st_value;
        else
                pp->dpp_stret[3] = 0;

        dt_dprintf("%s stret %llx %llx %llx %llx\n", obj,
            (u_longlong_t)pp->dpp_stret[0], (u_longlong_t)pp->dpp_stret[1],
            (u_longlong_t)pp->dpp_stret[2], (u_longlong_t)pp->dpp_stret[3]);

        /*
         * If pp->dpp_func contains any globbing meta-characters, we need
         * to iterate over the symbol table and compare each function name
         * against the pattern.
         */
        if (!strisglob(pp->dpp_func)) {
                /*
                 * If we fail to lookup the symbol, try interpreting the
                 * function as the special "-" function that indicates that the
                 * probe name should be interpreted as a absolute virtual
                 * address. If that fails and we were matching a specific
                 * function in a specific module, report the error, otherwise
                 * just fail silently in the hopes that some other object will
                 * contain the desired symbol.
                 */
                if (Pxlookup_by_name(pp->dpp_pr, pp->dpp_lmid, obj,
                    pp->dpp_func, &sym, NULL) != 0) {
                        if (strcmp("-", pp->dpp_func) == 0) {
                                sym.st_name = 0;
                                sym.st_info =
                                    GELF_ST_INFO(STB_LOCAL, STT_FUNC);
                                sym.st_other = 0;
                                sym.st_value = 0;
                                sym.st_size = Pstatus(pp->dpp_pr)->pr_dmodel ==
                                    PR_MODEL_ILP32 ? -1U : -1ULL;

                        } else if (!strisglob(pp->dpp_mod)) {
                                return (dt_pid_error(dtp, pcb, dpr, NULL,
                                    D_PROC_FUNC,
                                    "failed to lookup '%s' in module '%s'",
                                    pp->dpp_func, pp->dpp_mod));
                        } else {
                                return (0);
                        }
                }

                /*
                 * Only match defined functions of non-zero size.
                 */
                if (GELF_ST_TYPE(sym.st_info) != STT_FUNC ||
                    sym.st_shndx == SHN_UNDEF || sym.st_size == 0)
                        return (0);

                /*
                 * We don't instrument PLTs -- they're dynamically rewritten,
                 * and, so, inherently dicey to instrument.
                 */
                if (Ppltdest(pp->dpp_pr, sym.st_value) != NULL)
                        return (0);

                (void) Plookup_by_addr(pp->dpp_pr, sym.st_value, pp->dpp_func,
                    DTRACE_FUNCNAMELEN, &sym);

                return (dt_pid_per_sym(pp, &sym, pp->dpp_func));
        } else {
                uint_t nmatches = pp->dpp_nmatches;

                if (Psymbol_iter_by_addr(pp->dpp_pr, obj, PR_SYMTAB,
                    BIND_ANY | TYPE_FUNC, dt_pid_sym_filt, pp) == 1)
                        return (1);

                if (nmatches == pp->dpp_nmatches) {
                        /*
                         * If we didn't match anything in the PR_SYMTAB, try
                         * the PR_DYNSYM.
                         */
                        if (Psymbol_iter_by_addr(pp->dpp_pr, obj, PR_DYNSYM,
                            BIND_ANY | TYPE_FUNC, dt_pid_sym_filt, pp) == 1)
                                return (1);
                }
        }

        return (0);
}

static int
dt_pid_mod_filt(void *arg, const prmap_t *pmp, const char *obj)
{
        char name[DTRACE_MODNAMELEN];
        dt_pid_probe_t *pp = arg;

        if ((pp->dpp_obj = strrchr(obj, '/')) == NULL)
                pp->dpp_obj = obj;
        else
                pp->dpp_obj++;

        if (gmatch(pp->dpp_obj, pp->dpp_mod))
                return (dt_pid_per_mod(pp, pmp, obj));

        (void) Plmid(pp->dpp_pr, pmp->pr_vaddr, &pp->dpp_lmid);

        dt_pid_objname(name, sizeof (name), pp->dpp_lmid, pp->dpp_obj);

        if (gmatch(name, pp->dpp_mod))
                return (dt_pid_per_mod(pp, pmp, obj));

        return (0);
}

static const prmap_t *
dt_pid_fix_mod(dtrace_probedesc_t *pdp, struct ps_prochandle *P)
{
        char m[MAXPATHLEN];
        Lmid_t lmid = PR_LMID_EVERY;
        const char *obj;
        const prmap_t *pmp;

        /*
         * Pick apart the link map from the library name.
         */
        if (strchr(pdp->dtpd_mod, '`') != NULL) {
                char *end;

                if (strncmp(pdp->dtpd_mod, "LM", 2) != 0 ||
                    !isdigit(pdp->dtpd_mod[2]))
                        return (NULL);

                lmid = strtoul(&pdp->dtpd_mod[2], &end, 16);

                obj = end + 1;

                if (*end != '`' || strchr(obj, '`') != NULL)
                        return (NULL);

        } else {
                obj = pdp->dtpd_mod;
        }

        if ((pmp = Plmid_to_map(P, lmid, obj)) == NULL)
                return (NULL);

        (void) Pobjname(P, pmp->pr_vaddr, m, sizeof (m));
        if ((obj = strrchr(m, '/')) == NULL)
                obj = &m[0];
        else
                obj++;

        (void) Plmid(P, pmp->pr_vaddr, &lmid);
        dt_pid_objname(pdp->dtpd_mod, sizeof (pdp->dtpd_mod), lmid, obj);

        return (pmp);
}


static int
dt_pid_create_pid_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
    dt_pcb_t *pcb, dt_proc_t *dpr)
{
        dt_pid_probe_t pp;
        int ret = 0;

        pp.dpp_dtp = dtp;
        pp.dpp_dpr = dpr;
        pp.dpp_pr = dpr->dpr_proc;
        pp.dpp_pcb = pcb;

        /*
         * We can only trace dynamically-linked executables (since we've
         * hidden some magic in ld.so.1 as well as libc.so.1).
         */
        if (Pname_to_map(pp.dpp_pr, PR_OBJ_LDSO) == NULL) {
                return (dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_DYN,
                    "process %s is not a dynamically-linked executable",
                    &pdp->dtpd_provider[3]));
        }

        pp.dpp_mod = pdp->dtpd_mod[0] != '\0' ? pdp->dtpd_mod : "*";
        pp.dpp_func = pdp->dtpd_func[0] != '\0' ? pdp->dtpd_func : "*";
        pp.dpp_name = pdp->dtpd_name[0] != '\0' ? pdp->dtpd_name : "*";
        pp.dpp_last_taken = 0;

        if (strcmp(pp.dpp_func, "-") == 0) {
                const prmap_t *aout, *pmp;

                if (pdp->dtpd_mod[0] == '\0') {
                        pp.dpp_mod = pdp->dtpd_mod;
                        (void) strcpy(pdp->dtpd_mod, "a.out");
                } else if (strisglob(pp.dpp_mod) ||
                    (aout = Pname_to_map(pp.dpp_pr, "a.out")) == NULL ||
                    (pmp = Pname_to_map(pp.dpp_pr, pp.dpp_mod)) == NULL ||
                    aout->pr_vaddr != pmp->pr_vaddr) {
                        return (dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_LIB,
                            "only the a.out module is valid with the "
                            "'-' function"));
                }

                if (strisglob(pp.dpp_name)) {
                        return (dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_NAME,
                            "only individual addresses may be specified "
                            "with the '-' function"));
                }
        }

        /*
         * If pp.dpp_mod contains any globbing meta-characters, we need
         * to iterate over each module and compare its name against the
         * pattern. An empty module name is treated as '*'.
         */
        if (strisglob(pp.dpp_mod)) {
                ret = Pobject_iter(pp.dpp_pr, dt_pid_mod_filt, &pp);
        } else {
                const prmap_t *pmp;
                char *obj;

                /*
                 * If we can't find a matching module, don't sweat it -- either
                 * we'll fail the enabling because the probes don't exist or
                 * we'll wait for that module to come along.
                 */
                if ((pmp = dt_pid_fix_mod(pdp, pp.dpp_pr)) != NULL) {
                        if ((obj = strchr(pdp->dtpd_mod, '`')) == NULL)
                                obj = pdp->dtpd_mod;
                        else
                                obj++;

                        ret = dt_pid_per_mod(&pp, pmp, obj);
                }
        }

        return (ret);
}

static int
dt_pid_usdt_mapping(void *data, const prmap_t *pmp, const char *oname)
{
        struct ps_prochandle *P = data;
        GElf_Sym sym;
        prsyminfo_t sip;
        dof_helper_t dh;
        GElf_Half e_type;
        const char *mname;
        const char *syms[] = { "___SUNW_dof", "__SUNW_dof" };
        int i, fd = -1;

        /*
         * The symbol ___SUNW_dof is for lazy-loaded DOF sections, and
         * __SUNW_dof is for actively-loaded DOF sections. We try to force
         * in both types of DOF section since the process may not yet have
         * run the code to instantiate these providers.
         */
        for (i = 0; i < 2; i++) {
                if (Pxlookup_by_name(P, PR_LMID_EVERY, oname, syms[i], &sym,
                    &sip) != 0) {
                        continue;
                }

                if ((mname = strrchr(oname, '/')) == NULL)
                        mname = oname;
                else
                        mname++;

                dt_dprintf("lookup of %s succeeded for %s\n", syms[i], mname);

                if (Pread(P, &e_type, sizeof (e_type), pmp->pr_vaddr +
                    offsetof(Elf64_Ehdr, e_type)) != sizeof (e_type)) {
                        dt_dprintf("read of ELF header failed");
                        continue;
                }

                dh.dofhp_dof = sym.st_value;
                dh.dofhp_addr = (e_type == ET_EXEC) ? 0 : pmp->pr_vaddr;

                dt_pid_objname(dh.dofhp_mod, sizeof (dh.dofhp_mod),
                    sip.prs_lmid, mname);

                if (fd == -1 &&
                    (fd = pr_open(P, "/dev/dtrace/helper", O_RDWR, 0)) < 0) {
                        dt_dprintf("pr_open of helper device failed: %s\n",
                            strerror(errno));
                        return (-1); /* errno is set for us */
                }

                if (pr_ioctl(P, fd, DTRACEHIOC_ADDDOF, &dh, sizeof (dh)) < 0)
                        dt_dprintf("DOF was rejected for %s\n", dh.dofhp_mod);
        }

        if (fd != -1)
                (void) pr_close(P, fd);

        return (0);
}

static int
dt_pid_create_usdt_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
    dt_pcb_t *pcb, dt_proc_t *dpr)
{
        struct ps_prochandle *P = dpr->dpr_proc;
        int ret = 0;

        assert(MUTEX_HELD(&dpr->dpr_lock));

        (void) Pupdate_maps(P);
        if (Pobject_iter(P, dt_pid_usdt_mapping, P) != 0) {
                ret = -1;
                (void) dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_USDT,
                    "failed to instantiate probes for pid %d: %s",
                    (int)Pstatus(P)->pr_pid, strerror(errno));
        }

        /*
         * Put the module name in its canonical form.
         */
        (void) dt_pid_fix_mod(pdp, P);

        return (ret);
}

static pid_t
dt_pid_get_pid(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp, dt_pcb_t *pcb,
    dt_proc_t *dpr)
{
        pid_t pid;
        char *c, *last = NULL, *end;

        for (c = &pdp->dtpd_provider[0]; *c != '\0'; c++) {
                if (!isdigit(*c))
                        last = c;
        }

        if (last == NULL || (*(++last) == '\0')) {
                (void) dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_BADPROV,
                    "'%s' is not a valid provider", pdp->dtpd_provider);
                return (-1);
        }

        errno = 0;
        pid = strtol(last, &end, 10);

        if (errno != 0 || end == last || end[0] != '\0' || pid <= 0) {
                (void) dt_pid_error(dtp, pcb, dpr, NULL, D_PROC_BADPID,
                    "'%s' does not contain a valid pid", pdp->dtpd_provider);
                return (-1);
        }

        return (pid);
}

int
dt_pid_create_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp, dt_pcb_t *pcb)
{
        char provname[DTRACE_PROVNAMELEN];
        struct ps_prochandle *P;
        dt_proc_t *dpr;
        pid_t pid;
        int err = 0;

        assert(pcb != NULL);

        if ((pid = dt_pid_get_pid(pdp, dtp, pcb, NULL)) == -1)
                return (-1);

        if (dtp->dt_ftfd == -1) {
                if (dtp->dt_fterr == ENOENT) {
                        (void) dt_pid_error(dtp, pcb, NULL, NULL, D_PROC_NODEV,
                            "pid provider is not installed on this system");
                } else {
                        (void) dt_pid_error(dtp, pcb, NULL, NULL, D_PROC_NODEV,
                            "pid provider is not available: %s",
                            strerror(dtp->dt_fterr));
                }

                return (-1);
        }

        (void) snprintf(provname, sizeof (provname), "pid%d", (int)pid);

        if (gmatch(provname, pdp->dtpd_provider) != 0) {
                if ((P = dt_proc_grab(dtp, pid, PGRAB_RDONLY | PGRAB_FORCE,
                    0)) == NULL) {
                        (void) dt_pid_error(dtp, pcb, NULL, NULL, D_PROC_GRAB,
                            "failed to grab process %d", (int)pid);
                        return (-1);
                }

                dpr = dt_proc_lookup(dtp, P, 0);
                assert(dpr != NULL);
                (void) pthread_mutex_lock(&dpr->dpr_lock);

                if ((err = dt_pid_create_pid_probes(pdp, dtp, pcb, dpr)) == 0) {
                        /*
                         * Alert other retained enablings which may match
                         * against the newly created probes.
                         */
                        (void) dt_ioctl(dtp, DTRACEIOC_ENABLE, NULL);
                }

                (void) pthread_mutex_unlock(&dpr->dpr_lock);
                dt_proc_release(dtp, P);
        }

        /*
         * If it's not strictly a pid provider, we might match a USDT provider.
         */
        if (strcmp(provname, pdp->dtpd_provider) != 0) {
                if ((P = dt_proc_grab(dtp, pid, 0, 1)) == NULL) {
                        (void) dt_pid_error(dtp, pcb, NULL, NULL, D_PROC_GRAB,
                            "failed to grab process %d", (int)pid);
                        return (-1);
                }

                dpr = dt_proc_lookup(dtp, P, 0);
                assert(dpr != NULL);
                (void) pthread_mutex_lock(&dpr->dpr_lock);

                if (!dpr->dpr_usdt) {
                        err = dt_pid_create_usdt_probes(pdp, dtp, pcb, dpr);
                        dpr->dpr_usdt = B_TRUE;
                }

                (void) pthread_mutex_unlock(&dpr->dpr_lock);
                dt_proc_release(dtp, P);
        }

        return (err ? -1 : 0);
}

int
dt_pid_create_probes_module(dtrace_hdl_t *dtp, dt_proc_t *dpr)
{
        dtrace_prog_t *pgp;
        dt_stmt_t *stp;
        dtrace_probedesc_t *pdp, pd;
        pid_t pid;
        int ret = 0, found = B_FALSE;
        char provname[DTRACE_PROVNAMELEN];

        (void) snprintf(provname, sizeof (provname), "pid%d",
            (int)dpr->dpr_pid);

        for (pgp = dt_list_next(&dtp->dt_programs); pgp != NULL;
            pgp = dt_list_next(pgp)) {

                for (stp = dt_list_next(&pgp->dp_stmts); stp != NULL;
                    stp = dt_list_next(stp)) {

                        pdp = &stp->ds_desc->dtsd_ecbdesc->dted_probe;
                        pid = dt_pid_get_pid(pdp, dtp, NULL, dpr);
                        if (pid != dpr->dpr_pid)
                                continue;

                        found = B_TRUE;

                        pd = *pdp;

                        if (gmatch(provname, pdp->dtpd_provider) != 0 &&
                            dt_pid_create_pid_probes(&pd, dtp, NULL, dpr) != 0)
                                ret = 1;

                        /*
                         * If it's not strictly a pid provider, we might match
                         * a USDT provider.
                         */
                        if (strcmp(provname, pdp->dtpd_provider) != 0 &&
                            dt_pid_create_usdt_probes(&pd, dtp, NULL, dpr) != 0)
                                ret = 1;
                }
        }

        if (found) {
                /*
                 * Give DTrace a shot to the ribs to get it to check
                 * out the newly created probes.
                 */
                (void) dt_ioctl(dtp, DTRACEIOC_ENABLE, NULL);
        }

        return (ret);
}

/*
 * libdtrace has a backroom deal with us to ask us for type information on
 * behalf of pid provider probes when fasttrap doesn't return any type
 * information. Instead we'll look up the module and see if there is type
 * information available. However, if there is no type information available due
 * to a lack of CTF data, then we want to make sure that DTrace still carries on
 * in face of that. As such we don't have a meaningful exit code about failure.
 * We emit information about why we failed to the dtrace debug log so someone
 * can figure it out by asking nicely for DTRACE_DEBUG.
 */
void
dt_pid_get_types(dtrace_hdl_t *dtp, const dtrace_probedesc_t *pdp,
    dtrace_argdesc_t *adp, int *nargs)
{
        dt_module_t *dmp;
        ctf_file_t *fp;
        ctf_funcinfo_t f;
        ctf_id_t argv[32];
        GElf_Sym sym;
        prsyminfo_t si;
        struct ps_prochandle *p;
        int i, args;
        char buf[DTRACE_ARGTYPELEN];
        const char *mptr;
        char *eptr;
        int ret = 0;
        int argc = sizeof (argv) / sizeof (ctf_id_t);
        Lmid_t lmid;

        /* Set up a potential outcome */
        args = *nargs;
        *nargs = 0;

        /*
         * If we don't have an entry or return probe then we can just stop right
         * now as we don't have arguments for offset probes.
         */
        if (strcmp(pdp->dtpd_name, "entry") != 0 &&
            strcmp(pdp->dtpd_name, "return") != 0)
                return;

        dmp = dt_module_create(dtp, pdp->dtpd_provider);
        if (dmp == NULL) {
                dt_dprintf("failed to find module for %s\n",
                    pdp->dtpd_provider);
                return;
        }
        if (dt_module_load(dtp, dmp) != 0) {
                dt_dprintf("failed to load module for %s\n",
                    pdp->dtpd_provider);
                return;
        }

        /*
         * We may be working with a module that doesn't have ctf. If that's the
         * case then we just return now and move on with life.
         */
        fp = dt_module_getctflib(dtp, dmp, pdp->dtpd_mod);
        if (fp == NULL) {
                dt_dprintf("no ctf container for  %s\n",
                    pdp->dtpd_mod);
                return;
        }
        p = dt_proc_grab(dtp, dmp->dm_pid, 0, PGRAB_RDONLY | PGRAB_FORCE);
        if (p == NULL) {
                dt_dprintf("failed to grab pid\n");
                return;
        }
        dt_proc_lock(dtp, p);

        /*
         * Check to see if the D module has a link map ID and separate that out
         * for properly interrogating libproc.
         */
        if ((mptr = strchr(pdp->dtpd_mod, '`')) != NULL) {
                if (strlen(pdp->dtpd_mod) < 3) {
                        dt_dprintf("found weird modname with linkmap, "
                            "aborting: %s\n", pdp->dtpd_mod);
                        goto out;
                }
                if (pdp->dtpd_mod[0] != 'L' || pdp->dtpd_mod[1] != 'M') {
                        dt_dprintf("missing leading 'LM', "
                            "aborting: %s\n", pdp->dtpd_mod);
                        goto out;
                }
                errno = 0;
                lmid = strtol(pdp->dtpd_mod + 2, &eptr, 16);
                if (errno == ERANGE || eptr != mptr) {
                        dt_dprintf("failed to parse out lmid, aborting: %s\n",
                            pdp->dtpd_mod);
                        goto out;
                }
                mptr++;
        } else {
                mptr = pdp->dtpd_mod;
                lmid = 0;
        }

        if (Pxlookup_by_name(p, lmid, mptr, pdp->dtpd_func,
            &sym, &si) != 0) {
                dt_dprintf("failed to find function %s in %s`%s\n",
                    pdp->dtpd_func, pdp->dtpd_provider, pdp->dtpd_mod);
                goto out;
        }
        if (ctf_func_info(fp, si.prs_id, &f) == CTF_ERR) {
                dt_dprintf("failed to get ctf information for %s in %s`%s\n",
                    pdp->dtpd_func, pdp->dtpd_provider, pdp->dtpd_mod);
                goto out;
        }

        (void) snprintf(buf, sizeof (buf), "%s`%s", pdp->dtpd_provider,
            pdp->dtpd_mod);

        if (strcmp(pdp->dtpd_name, "return") == 0) {
                if (args < 2)
                        goto out;

                bzero(adp, sizeof (dtrace_argdesc_t));
                adp->dtargd_ndx = 0;
                adp->dtargd_id = pdp->dtpd_id;
                adp->dtargd_mapping = adp->dtargd_ndx;
                /*
                 * We explicitly leave out the library here, we only care that
                 * it is some int. We are assuming that there is no ctf
                 * container in here that is lying about what an int is.
                 */
                (void) snprintf(adp->dtargd_native, DTRACE_ARGTYPELEN,
                    "user %s`%s", pdp->dtpd_provider, "int");
                adp++;
                bzero(adp, sizeof (dtrace_argdesc_t));
                adp->dtargd_ndx = 1;
                adp->dtargd_id = pdp->dtpd_id;
                adp->dtargd_mapping = adp->dtargd_ndx;
                ret = snprintf(adp->dtargd_native, DTRACE_ARGTYPELEN,
                    "userland ");
                (void) ctf_type_qname(fp, f.ctc_return, adp->dtargd_native +
                    ret, DTRACE_ARGTYPELEN - ret, buf);
                *nargs = 2;
        } else {
                if (ctf_func_args(fp, si.prs_id, argc, argv) == CTF_ERR)
                        goto out;

                *nargs = MIN(args, f.ctc_argc);
                for (i = 0; i < *nargs; i++, adp++) {
                        bzero(adp, sizeof (dtrace_argdesc_t));
                        adp->dtargd_ndx = i;
                        adp->dtargd_id = pdp->dtpd_id;
                        adp->dtargd_mapping = adp->dtargd_ndx;
                        ret = snprintf(adp->dtargd_native, DTRACE_ARGTYPELEN,
                            "userland ");
                        (void) ctf_type_qname(fp, argv[i], adp->dtargd_native +
                            ret, DTRACE_ARGTYPELEN - ret, buf);
                }
        }
out:
        dt_proc_unlock(dtp, p);
        dt_proc_release(dtp, p);
}