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 #include <stdio.h>
  28 #include <fcntl.h>
  29 #include <ctype.h>
  30 #include <string.h>
  31 #include <signal.h>
  32 #include <errno.h>
  33 #include <stdlib.h>
  34 #include <stdarg.h>
  35 #include <unistd.h>
  36 #include <limits.h>
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39
  40 #include <libelf.h>
  41 #include <link.h>
  42 #include <elf.h>
  43 #include <sys/machelf.h>
  44
  45 #include <kstat.h>
  46 #include <sys/cpuvar.h>
  47
  48 typedef struct syment {
  49         uintptr_t       addr;
  50         char            *name;
  51         size_t          size;
  52 } syment_t;
  53
  54 static syment_t *symbol_table;
  55 static int nsyms, maxsyms;
  56 static char maxsymname[64];
  57
  58 #ifdef _ELF64
  59 #define elf_getshdr elf64_getshdr
  60 #else
  61 #define elf_getshdr elf32_getshdr
  62 #endif
  63
  64 static void
  65 add_symbol(char *name, uintptr_t addr, size_t size)
  66 {
  67         syment_t *sep;
  68
  69         if (nsyms >= maxsyms) {
  70                 maxsyms += 10000;
  71                 symbol_table = realloc(symbol_table, maxsyms * sizeof (*sep));
  72                 if (symbol_table == NULL) {
  73                         (void) fprintf(stderr, "can't allocate symbol table\n");
  74                         exit(3);
  75                 }
  76         }
  77         sep = &symbol_table[nsyms++];
  78
  79         sep->name = name;
  80         sep->addr = addr;
  81         sep->size = size;
  82 }
  83
  84 static void
  85 remove_symbol(uintptr_t addr)
  86 {
  87         int i;
  88         syment_t *sep = symbol_table;
  89
  90         for (i = 0; i < nsyms; i++, sep++)
  91                 if (sep->addr == addr)
  92                         sep->addr = 0;
  93 }
  94
  95 static void
  96 fake_up_certain_popular_kernel_symbols(void)
  97 {
  98         kstat_ctl_t *kc;
  99         kstat_t *ksp;
 100         char *name;
 101
 102         if ((kc = kstat_open()) == NULL)
 103                 return;
 104
 105         for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
 106                 if (strcmp(ksp->ks_module, "cpu_info") == 0) {
 107                         if ((name = malloc(20)) == NULL)
 108                                 break;
 109                         /*
 110                          * For consistency, keep cpu[0] and toss cpu0
 111                          * or any other such symbols.
 112                          */
 113                         if (ksp->ks_instance == 0)
 114                                 remove_symbol((uintptr_t)ksp->ks_private);
 115                         (void) sprintf(name, "cpu[%d]", ksp->ks_instance);
 116                         add_symbol(name, (uintptr_t)ksp->ks_private,
 117                             sizeof (struct cpu));
 118                 }
 119         }
 120         (void) kstat_close(kc);
 121 }
 122
 123 static int
 124 symcmp(const void *p1, const void *p2)
 125 {
 126         uintptr_t a1 = ((syment_t *)p1)->addr;
 127         uintptr_t a2 = ((syment_t *)p2)->addr;
 128
 129         if (a1 < a2)
 130                 return (-1);
 131         if (a1 > a2)
 132                 return (1);
 133         return (0);
 134 }
 135
 136 int
 137 symtab_init(void)
 138 {
 139         Elf             *elf;
 140         Elf_Scn         *scn = NULL;
 141         Sym             *symtab, *symp, *lastsym;
 142         char            *strtab;
 143         uint_t          cnt;
 144         int             fd;
 145         int             i;
 146         int             strindex = -1;
 147
 148         if ((fd = open("/dev/ksyms", O_RDONLY)) == -1)
 149                 return (-1);
 150
 151         (void) elf_version(EV_CURRENT);
 152
 153         elf = elf_begin(fd, ELF_C_READ, NULL);
 154
 155         for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
 156                 Shdr *shdr = elf_getshdr(scn);
 157                 if (shdr->sh_type == SHT_SYMTAB) {
 158                         symtab = (Sym *)elf_getdata(scn, NULL)->d_buf;
 159                         nsyms = shdr->sh_size / shdr->sh_entsize;
 160                         strindex = shdr->sh_link;
 161                 }
 162         }
 163
 164         for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
 165                 if (cnt == strindex)
 166                         strtab = (char *)elf_getdata(scn, NULL)->d_buf;
 167         }
 168
 169         lastsym = symtab + nsyms;
 170         nsyms = 0;
 171         for (symp = symtab; symp < lastsym; symp++)
 172                 if ((uint_t)ELF32_ST_TYPE(symp->st_info) <= STT_FUNC &&
 173                     symp->st_size != 0)
 174                         add_symbol(symp->st_name + strtab,
 175                             (uintptr_t)symp->st_value, (size_t)symp->st_size);
 176
 177         fake_up_certain_popular_kernel_symbols();
 178         (void) sprintf(maxsymname, "0x%lx", ULONG_MAX);
 179         add_symbol(maxsymname, ULONG_MAX, 1);
 180
 181         qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
 182
 183         /*
 184          * Destroy all duplicate symbols, then sort it again.
 185          */
 186         for (i = 0; i < nsyms - 1; i++)
 187                 if (symbol_table[i].addr == symbol_table[i + 1].addr)
 188                         symbol_table[i].addr = 0;
 189
 190         qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
 191
 192         while (symbol_table[1].addr == 0) {
 193                 symbol_table++;
 194                 nsyms--;
 195         }
 196         symbol_table[0].name = "(usermode)";
 197         symbol_table[0].addr = 0;
 198         symbol_table[0].size = 1;
 199
 200         return (0);
 201 }
 202
 203 char *
 204 addr_to_sym(uintptr_t addr, uintptr_t *offset, size_t *sizep)
 205 {
 206         int lo = 0;
 207         int hi = nsyms - 1;
 208         int mid;
 209         syment_t *sep;
 210
 211         while (hi - lo > 1) {
 212                 mid = (lo + hi) / 2;
 213                 if (addr >= symbol_table[mid].addr) {
 214                         lo = mid;
 215                 } else {
 216                         hi = mid;
 217                 }
 218         }
 219         sep = &symbol_table[lo];
 220         *offset = addr - sep->addr;
 221         *sizep = sep->size;
 222         return (sep->name);
 223 }
 224
 225 uintptr_t
 226 sym_to_addr(char *name)
 227 {
 228         int i;
 229         syment_t *sep = symbol_table;
 230
 231         for (i = 0; i < nsyms; i++) {
 232                 if (strcmp(name, sep->name) == 0)
 233                         return (sep->addr);
 234                 sep++;
 235         }
 236         return (0);
 237 }
 238
 239 size_t
 240 sym_size(char *name)
 241 {
 242         int i;
 243         syment_t *sep = symbol_table;
 244
 245         for (i = 0; i < nsyms; i++) {
 246                 if (strcmp(name, sep->name) == 0)
 247                         return (sep->size);
 248                 sep++;
 249         }
 250         return (0);
 251 }