usr/src/cmd/lockstat/sym.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 1997-1999 by Sun Microsystems, Inc.
  24  * All rights reserved.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include <stdio.h>
  30 #include <fcntl.h>
  31 #include <ctype.h>
  32 #include <string.h>
  33 #include <signal.h>
  34 #include <errno.h>
  35 #include <stdlib.h>
  36 #include <stdarg.h>
  37 #include <unistd.h>
  38 #include <limits.h>
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41
  42 #include <libelf.h>
  43 #include <link.h>
  44 #include <elf.h>
  45 #include <sys/machelf.h>
  46
  47 #include <kstat.h>
  48 #include <sys/cpuvar.h>
  49
  50 typedef struct syment {
  51         uintptr_t       addr;
  52         char            *name;
  53         size_t          size;
  54 } syment_t;
  55
  56 static syment_t *symbol_table;
  57 static int nsyms, maxsyms;
  58 static char maxsymname[64];
  59
  60 #ifdef _ELF64
  61 #define elf_getshdr elf64_getshdr
  62 #else
  63 #define elf_getshdr elf32_getshdr
  64 #endif
  65
  66 static void
  67 add_symbol(char *name, uintptr_t addr, size_t size)
  68 {
  69         syment_t *sep;
  70
  71         if (nsyms >= maxsyms) {
  72                 maxsyms += 10000;
  73                 symbol_table = realloc(symbol_table, maxsyms * sizeof (*sep));
  74                 if (symbol_table == NULL) {
  75                         (void) fprintf(stderr, "can't allocate symbol table\n");
  76                         exit(3);
  77                 }
  78         }
  79         sep = &symbol_table[nsyms++];
  80
  81         sep->name = name;
  82         sep->addr = addr;
  83         sep->size = size;
  84 }
  85
  86 static void
  87 remove_symbol(uintptr_t addr)
  88 {
  89         int i;
  90         syment_t *sep = symbol_table;
  91
  92         for (i = 0; i < nsyms; i++, sep++)
  93                 if (sep->addr == addr)
  94                         sep->addr = 0;
  95 }
  96
  97 static void
  98 fake_up_certain_popular_kernel_symbols(void)
  99 {
 100         kstat_ctl_t *kc;
 101         kstat_t *ksp;
 102         char *name;
 103
 104         if ((kc = kstat_open()) == NULL)
 105                 return;
 106
 107         for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
 108                 if (strcmp(ksp->ks_module, "cpu_info") == 0) {
 109                         if ((name = malloc(20)) == NULL)
 110                                 break;
 111                         /*
 112                          * For consistency, keep cpu[0] and toss cpu0
 113                          * or any other such symbols.
 114                          */
 115                         if (ksp->ks_instance == 0)
 116                                 remove_symbol((uintptr_t)ksp->ks_private);
 117                         (void) sprintf(name, "cpu[%d]", ksp->ks_instance);
 118                         add_symbol(name, (uintptr_t)ksp->ks_private,
 119                             sizeof (struct cpu));
 120                 }
 121         }
 122         (void) kstat_close(kc);
 123 }
 124
 125 static int
 126 symcmp(const void *p1, const void *p2)
 127 {
 128         uintptr_t a1 = ((syment_t *)p1)->addr;
 129         uintptr_t a2 = ((syment_t *)p2)->addr;
 130
 131         if (a1 < a2)
 132                 return (-1);
 133         if (a1 > a2)
 134                 return (1);
 135         return (0);
 136 }
 137
 138 int
 139 symtab_init(void)
 140 {
 141         Elf             *elf;
 142         Elf_Scn         *scn = NULL;
 143         Sym             *symtab, *symp, *lastsym;
 144         char            *strtab;
 145         uint_t          cnt;
 146         int             fd;
 147         int             i;
 148         int             strindex = -1;
 149
 150         if ((fd = open("/dev/ksyms", O_RDONLY)) == -1)
 151                 return (-1);
 152
 153         (void) elf_version(EV_CURRENT);
 154
 155         elf = elf_begin(fd, ELF_C_READ, NULL);
 156
 157         for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
 158                 Shdr *shdr = elf_getshdr(scn);
 159                 if (shdr->sh_type == SHT_SYMTAB) {
 160                         symtab = (Sym *)elf_getdata(scn, NULL)->d_buf;
 161                         nsyms = shdr->sh_size / shdr->sh_entsize;
 162                         strindex = shdr->sh_link;
 163                 }
 164         }
 165
 166         for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
 167                 if (cnt == strindex)
 168                         strtab = (char *)elf_getdata(scn, NULL)->d_buf;
 169         }
 170
 171         lastsym = symtab + nsyms;
 172         nsyms = 0;
 173         for (symp = symtab; symp < lastsym; symp++)
 174                 if ((uint_t)ELF32_ST_TYPE(symp->st_info) <= STT_FUNC &&
 175                     symp->st_size != 0)
 176                         add_symbol(symp->st_name + strtab,
 177                             (uintptr_t)symp->st_value, (size_t)symp->st_size);
 178
 179         fake_up_certain_popular_kernel_symbols();
 180         (void) sprintf(maxsymname, "0x%lx", ULONG_MAX);
 181         add_symbol(maxsymname, ULONG_MAX, 1);
 182
 183         qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
 184
 185         /*
 186          * Destroy all duplicate symbols, then sort it again.
 187          */
 188         for (i = 0; i < nsyms - 1; i++)
 189                 if (symbol_table[i].addr == symbol_table[i + 1].addr)
 190                         symbol_table[i].addr = 0;
 191
 192         qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
 193
 194         while (symbol_table[1].addr == 0) {
 195                 symbol_table++;
 196                 nsyms--;
 197         }
 198         symbol_table[0].name = "(usermode)";
 199         symbol_table[0].addr = 0;
 200         symbol_table[0].size = 1;
 201
 202         return (0);
 203 }
 204
 205 char *
 206 addr_to_sym(uintptr_t addr, uintptr_t *offset, size_t *sizep)
 207 {
 208         int lo = 0;
 209         int hi = nsyms - 1;
 210         int mid;
 211         syment_t *sep;
 212
 213         while (hi - lo > 1) {
 214                 mid = (lo + hi) / 2;
 215                 if (addr >= symbol_table[mid].addr) {
 216                         lo = mid;
 217                 } else {
 218                         hi = mid;
 219                 }
 220         }
 221         sep = &symbol_table[lo];
 222         *offset = addr - sep->addr;
 223         *sizep = sep->size;
 224         return (sep->name);
 225 }
 226
 227 uintptr_t
 228 sym_to_addr(char *name)
 229 {
 230         int i;
 231         syment_t *sep = symbol_table;
 232
 233         for (i = 0; i < nsyms; i++) {
 234                 if (strcmp(name, sep->name) == 0)
 235                         return (sep->addr);
 236                 sep++;
 237         }
 238         return (NULL);
 239 }
 240
 241 size_t
 242 sym_size(char *name)
 243 {
 244         int i;
 245         syment_t *sep = symbol_table;
 246
 247         for (i = 0; i < nsyms; i++) {
 248                 if (strcmp(name, sep->name) == 0)
 249                         return (sep->size);
 250                 sep++;
 251         }
 252         return (0);
 253 }