sym.c revision 302408
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#ifdef illumos 46#include <sys/machelf.h> 47 48#include <kstat.h> 49#else 50#include <sys/elf.h> 51#include <sys/ksyms.h> 52#include <sys/param.h> 53#include <sys/module.h> 54#include <sys/linker.h> 55#endif 56#include <sys/cpuvar.h> 57 58typedef struct syment { 59 uintptr_t addr; 60 char *name; 61 size_t size; 62} syment_t; 63 64static syment_t *symbol_table; 65static int nsyms, maxsyms; 66static char maxsymname[64]; 67 68#ifdef illumos 69#ifdef _ELF64 70#define elf_getshdr elf64_getshdr 71#else 72#define elf_getshdr elf32_getshdr 73#endif 74#endif 75 76static void 77add_symbol(char *name, uintptr_t addr, size_t size) 78{ 79 syment_t *sep; 80 81 if (nsyms >= maxsyms) { 82 maxsyms += 10000; 83 symbol_table = realloc(symbol_table, maxsyms * sizeof (*sep)); 84 if (symbol_table == NULL) { 85 (void) fprintf(stderr, "can't allocate symbol table\n"); 86 exit(3); 87 } 88 } 89 sep = &symbol_table[nsyms++]; 90 91 sep->name = name; 92 sep->addr = addr; 93 sep->size = size; 94} 95 96static void 97remove_symbol(uintptr_t addr) 98{ 99 int i; 100 syment_t *sep = symbol_table; 101 102 for (i = 0; i < nsyms; i++, sep++) 103 if (sep->addr == addr) 104 sep->addr = 0; 105} 106 107#ifdef illumos 108static void 109fake_up_certain_popular_kernel_symbols(void) 110{ 111 kstat_ctl_t *kc; 112 kstat_t *ksp; 113 char *name; 114 115 if ((kc = kstat_open()) == NULL) 116 return; 117 118 for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) { 119 if (strcmp(ksp->ks_module, "cpu_info") == 0) { 120 if ((name = malloc(20)) == NULL) 121 break; 122 /* 123 * For consistency, keep cpu[0] and toss cpu0 124 * or any other such symbols. 125 */ 126 if (ksp->ks_instance == 0) 127 remove_symbol((uintptr_t)ksp->ks_private); 128 (void) sprintf(name, "cpu[%d]", ksp->ks_instance); 129 add_symbol(name, (uintptr_t)ksp->ks_private, 130 sizeof (struct cpu)); 131 } 132 } 133 (void) kstat_close(kc); 134} 135#else /* !illumos */ 136static void 137fake_up_certain_popular_kernel_symbols(void) 138{ 139 char *name; 140 uintptr_t addr; 141 int i; 142 143 /* Good for up to 256 CPUs */ 144 for(i=0; i < 256; i++) { 145 if ((name = malloc(20)) == NULL) 146 break; 147 (void) sprintf(name, "cpu[%d]", i); 148 addr = 0x01000000 + (i << 16); 149 add_symbol(name, addr, sizeof (uintptr_t)); 150 } 151} 152#endif /* illumos */ 153 154static int 155symcmp(const void *p1, const void *p2) 156{ 157 uintptr_t a1 = ((syment_t *)p1)->addr; 158 uintptr_t a2 = ((syment_t *)p2)->addr; 159 160 if (a1 < a2) 161 return (-1); 162 if (a1 > a2) 163 return (1); 164 return (0); 165} 166 167int 168symtab_init(void) 169{ 170 Elf *elf; 171 Elf_Scn *scn = NULL; 172 Sym *symtab, *symp, *lastsym; 173 char *strtab; 174 uint_t cnt; 175 int fd; 176 int i; 177 int strindex = -1; 178#ifndef illumos 179 void *ksyms; 180 size_t sz; 181#endif 182 183#ifndef illumos 184 if ((fd = open("/dev/ksyms", O_RDONLY)) == -1) { 185 if (errno == ENOENT && modfind("ksyms") == -1) { 186 kldload("ksyms"); 187 fd = open("/dev/ksyms", O_RDONLY); 188 } 189 if (fd == -1) 190 return (-1); 191 } 192#else 193 if ((fd = open("/dev/ksyms", O_RDONLY)) == -1) 194 return (-1); 195#endif 196 197#ifdef illumos 198 (void) elf_version(EV_CURRENT); 199 200 elf = elf_begin(fd, ELF_C_READ, NULL); 201#else 202 /* 203 * XXX - libelf needs to be fixed so it will work with 204 * non 'ordinary' files like /dev/ksyms. The following 205 * is a work around for now. 206 */ 207 if (elf_version(EV_CURRENT) == EV_NONE) { 208 close(fd); 209 return (-1); 210 } 211 if (ioctl(fd, KIOCGSIZE, &sz) < 0) { 212 close(fd); 213 return (-1); 214 } 215 if (ioctl(fd, KIOCGADDR, &ksyms) < 0) { 216 close(fd); 217 return (-1); 218 } 219 if ((elf = elf_memory(ksyms, sz)) == NULL) { 220 close(fd); 221 return (-1); 222 } 223#endif 224 225 for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) { 226 Shdr *shdr = elf_getshdr(scn); 227 if (shdr->sh_type == SHT_SYMTAB) { 228 symtab = (Sym *)elf_getdata(scn, NULL)->d_buf; 229 nsyms = shdr->sh_size / shdr->sh_entsize; 230 strindex = shdr->sh_link; 231 } 232 } 233 234 for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) { 235 if (cnt == strindex) 236 strtab = (char *)elf_getdata(scn, NULL)->d_buf; 237 } 238 239 lastsym = symtab + nsyms; 240 nsyms = 0; 241 for (symp = symtab; symp < lastsym; symp++) 242 if ((uint_t)ELF32_ST_TYPE(symp->st_info) <= STT_FUNC && 243 symp->st_size != 0) 244 add_symbol(symp->st_name + strtab, 245 (uintptr_t)symp->st_value, (size_t)symp->st_size); 246 247 fake_up_certain_popular_kernel_symbols(); 248 (void) sprintf(maxsymname, "0x%lx", ULONG_MAX); 249 add_symbol(maxsymname, ULONG_MAX, 1); 250 251 qsort(symbol_table, nsyms, sizeof (syment_t), symcmp); 252 253 /* 254 * Destroy all duplicate symbols, then sort it again. 255 */ 256 for (i = 0; i < nsyms - 1; i++) 257 if (symbol_table[i].addr == symbol_table[i + 1].addr) 258 symbol_table[i].addr = 0; 259 260 qsort(symbol_table, nsyms, sizeof (syment_t), symcmp); 261 262 while (symbol_table[1].addr == 0) { 263 symbol_table++; 264 nsyms--; 265 } 266 symbol_table[0].name = "(usermode)"; 267 symbol_table[0].addr = 0; 268 symbol_table[0].size = 1; 269 270 close(fd); 271 return (0); 272} 273 274char * 275addr_to_sym(uintptr_t addr, uintptr_t *offset, size_t *sizep) 276{ 277 int lo = 0; 278 int hi = nsyms - 1; 279 int mid; 280 syment_t *sep; 281 282 while (hi - lo > 1) { 283 mid = (lo + hi) / 2; 284 if (addr >= symbol_table[mid].addr) { 285 lo = mid; 286 } else { 287 hi = mid; 288 } 289 } 290 sep = &symbol_table[lo]; 291 *offset = addr - sep->addr; 292 *sizep = sep->size; 293 return (sep->name); 294} 295 296uintptr_t 297sym_to_addr(char *name) 298{ 299 int i; 300 syment_t *sep = symbol_table; 301 302 for (i = 0; i < nsyms; i++) { 303 if (strcmp(name, sep->name) == 0) 304 return (sep->addr); 305 sep++; 306 } 307 return (0); 308} 309 310size_t 311sym_size(char *name) 312{ 313 int i; 314 syment_t *sep = symbol_table; 315 316 for (i = 0; i < nsyms; i++) { 317 if (strcmp(name, sep->name) == 0) 318 return (sep->size); 319 sep++; 320 } 321 return (0); 322} 323