| File: | jdk/src/jdk.hotspot.agent/linux/native/libsaproc/symtab.c |
| Warning: | line 389, column 7 Value stored to 'htab_sz' is never read |
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| 1 | /* |
| 2 | * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| 13 | * accompanied this code). |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License version |
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | * |
| 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| 20 | * or visit www.oracle.com if you need additional information or have any |
| 21 | * questions. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | #include <unistd.h> |
| 26 | #include <sys/procfs.h> |
| 27 | #include <search.h> |
| 28 | #include <stdlib.h> |
| 29 | #include <string.h> |
| 30 | #include "symtab.h" |
| 31 | #include "salibelf.h" |
| 32 | |
| 33 | |
| 34 | // ---------------------------------------------------- |
| 35 | // functions for symbol lookups |
| 36 | // ---------------------------------------------------- |
| 37 | |
| 38 | struct elf_symbol { |
| 39 | char *name; |
| 40 | uintptr_t offset; |
| 41 | uintptr_t size; |
| 42 | }; |
| 43 | |
| 44 | typedef struct symtab { |
| 45 | char *strs; |
| 46 | size_t num_symbols; |
| 47 | struct elf_symbol *symbols; |
| 48 | struct hsearch_data *hash_table; |
| 49 | } symtab_t; |
| 50 | |
| 51 | |
| 52 | // Directory that contains global debuginfo files. In theory it |
| 53 | // should be possible to change this, but in a Java environment there |
| 54 | // is no obvious place to put a user interface to do it. Maybe this |
| 55 | // could be set with an environment variable. |
| 56 | static const char debug_file_directory[] = "/usr/lib/debug"; |
| 57 | |
| 58 | /* The CRC used in gnu_debuglink, retrieved from |
| 59 | http://sourceware.org/gdb/current/onlinedocs/gdb/Separate-Debug-Files.html#Separate-Debug-Files. */ |
| 60 | unsigned int gnu_debuglink_crc32 (unsigned int crc, |
| 61 | unsigned char *buf, size_t len) |
| 62 | { |
| 63 | static const unsigned int crc32_table[256] = |
| 64 | { |
| 65 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, |
| 66 | 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, |
| 67 | 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, |
| 68 | 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, |
| 69 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, |
| 70 | 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, |
| 71 | 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, |
| 72 | 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, |
| 73 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, |
| 74 | 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, |
| 75 | 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, |
| 76 | 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, |
| 77 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, |
| 78 | 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, |
| 79 | 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, |
| 80 | 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, |
| 81 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, |
| 82 | 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, |
| 83 | 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, |
| 84 | 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, |
| 85 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, |
| 86 | 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, |
| 87 | 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, |
| 88 | 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, |
| 89 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, |
| 90 | 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, |
| 91 | 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, |
| 92 | 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, |
| 93 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, |
| 94 | 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, |
| 95 | 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, |
| 96 | 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, |
| 97 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, |
| 98 | 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, |
| 99 | 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, |
| 100 | 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, |
| 101 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, |
| 102 | 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, |
| 103 | 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, |
| 104 | 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, |
| 105 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, |
| 106 | 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, |
| 107 | 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, |
| 108 | 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, |
| 109 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, |
| 110 | 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, |
| 111 | 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, |
| 112 | 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, |
| 113 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, |
| 114 | 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, |
| 115 | 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, |
| 116 | 0x2d02ef8d |
| 117 | }; |
| 118 | unsigned char *end; |
| 119 | |
| 120 | crc = ~crc & 0xffffffff; |
| 121 | for (end = buf + len; buf < end; ++buf) |
| 122 | crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8); |
| 123 | return ~crc & 0xffffffff; |
| 124 | } |
| 125 | |
| 126 | /* Open a debuginfo file and check its CRC. If it exists and the CRC |
| 127 | matches return its fd. */ |
| 128 | static int |
| 129 | open_debug_file (const char *pathname, unsigned int crc) |
| 130 | { |
| 131 | unsigned int file_crc = 0; |
| 132 | unsigned char buffer[8 * 1024]; |
| 133 | |
| 134 | int fd = pathmap_open(pathname); |
| 135 | |
| 136 | if (fd < 0) |
| 137 | return -1; |
| 138 | |
| 139 | lseek(fd, 0, SEEK_SET0); |
| 140 | |
| 141 | for (;;) { |
| 142 | int len = read(fd, buffer, sizeof buffer); |
| 143 | if (len <= 0) |
| 144 | break; |
| 145 | file_crc = gnu_debuglink_crc32(file_crc, buffer, len); |
| 146 | } |
| 147 | |
| 148 | if (crc == file_crc) |
| 149 | return fd; |
| 150 | else { |
| 151 | close(fd); |
| 152 | return -1; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | /* Look for a ".gnu_debuglink" section. If one exists, try to open a |
| 157 | suitable debuginfo file. */ |
| 158 | static int open_file_from_debug_link(const char *name, |
| 159 | int fd, |
| 160 | ELF_EHDRElf64_Ehdr *ehdr, |
| 161 | struct elf_section *scn_cache) |
| 162 | { |
| 163 | int debug_fd; |
| 164 | struct elf_section *debug_link = find_section_by_name(".gnu_debuglink", fd, ehdr, |
| 165 | scn_cache); |
| 166 | if (debug_link == NULL((void*)0)) |
| 167 | return -1; |
| 168 | char *debug_filename = debug_link->c_data; |
| 169 | int offset = (strlen(debug_filename) + 4) >> 2; |
| 170 | static unsigned int crc; |
| 171 | crc = ((unsigned int*)debug_link->c_data)[offset]; |
| 172 | char *debug_pathname = malloc(strlen(debug_filename) |
| 173 | + strlen(name) |
| 174 | + strlen(".debug/") |
| 175 | + strlen(debug_file_directory) |
| 176 | + 2); |
| 177 | if (debug_pathname == NULL((void*)0)) { |
| 178 | return -1; |
| 179 | } |
| 180 | strcpy(debug_pathname, name); |
| 181 | char *last_slash = strrchr(debug_pathname, '/'); |
| 182 | if (last_slash == NULL((void*)0)) { |
| 183 | free(debug_pathname); |
| 184 | return -1; |
| 185 | } |
| 186 | |
| 187 | /* Look in the same directory as the object. */ |
| 188 | strcpy(last_slash+1, debug_filename); |
| 189 | debug_fd = open_debug_file(debug_pathname, crc); |
| 190 | if (debug_fd >= 0) { |
| 191 | free(debug_pathname); |
| 192 | return debug_fd; |
| 193 | } |
| 194 | |
| 195 | /* Look in a subdirectory named ".debug". */ |
| 196 | strcpy(last_slash+1, ".debug/"); |
| 197 | strcat(last_slash, debug_filename); |
| 198 | |
| 199 | debug_fd = open_debug_file(debug_pathname, crc); |
| 200 | if (debug_fd >= 0) { |
| 201 | free(debug_pathname); |
| 202 | return debug_fd; |
| 203 | } |
| 204 | |
| 205 | /* Look in /usr/lib/debug + the full pathname. */ |
| 206 | strcpy(debug_pathname, debug_file_directory); |
| 207 | strcat(debug_pathname, name); |
| 208 | last_slash = strrchr(debug_pathname, '/'); |
| 209 | strcpy(last_slash+1, debug_filename); |
| 210 | |
| 211 | debug_fd = open_debug_file(debug_pathname, crc); |
| 212 | if (debug_fd >= 0) { |
| 213 | free(debug_pathname); |
| 214 | return debug_fd; |
| 215 | } |
| 216 | |
| 217 | free(debug_pathname); |
| 218 | return -1; |
| 219 | } |
| 220 | |
| 221 | static struct symtab* build_symtab_internal(int fd, const char *filename, bool try_debuginfo); |
| 222 | |
| 223 | /* Look for a ".gnu_debuglink" section. If one exists, try to open a |
| 224 | suitable debuginfo file and read a symbol table from it. */ |
| 225 | static struct symtab *build_symtab_from_debug_link(const char *name, |
| 226 | int fd, |
| 227 | ELF_EHDRElf64_Ehdr *ehdr, |
| 228 | struct elf_section *scn_cache) |
| 229 | { |
| 230 | fd = open_file_from_debug_link(name, fd, ehdr, scn_cache); |
| 231 | |
| 232 | if (fd >= 0) { |
| 233 | struct symtab *symtab = build_symtab_internal(fd, NULL((void*)0), /* try_debuginfo */ false0); |
| 234 | close(fd); |
| 235 | return symtab; |
| 236 | } |
| 237 | |
| 238 | return NULL((void*)0); |
| 239 | } |
| 240 | |
| 241 | // Given a build_id, find the associated debuginfo file |
| 242 | static char * |
| 243 | build_id_to_debug_filename (size_t size, unsigned char *data) |
| 244 | { |
| 245 | char *filename, *s; |
| 246 | |
| 247 | filename = malloc(strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1 |
| 248 | + 2 * size + (sizeof ".debug" - 1) + 1); |
| 249 | if (filename == NULL((void*)0)) { |
| 250 | return NULL((void*)0); |
| 251 | } |
| 252 | s = filename + sprintf (filename, "%s/.build-id/", debug_file_directory)__builtin___sprintf_chk (filename, 2 - 1, __builtin_object_size (filename, 2 > 1), "%s/.build-id/", debug_file_directory); |
| 253 | if (size > 0) |
| 254 | { |
| 255 | size--; |
| 256 | s += sprintf (s, "%02x", *data++)__builtin___sprintf_chk (s, 2 - 1, __builtin_object_size (s, 2 > 1), "%02x", *data++); |
| 257 | } |
| 258 | if (size > 0) |
| 259 | *s++ = '/'; |
| 260 | while (size-- > 0) |
| 261 | s += sprintf (s, "%02x", *data++)__builtin___sprintf_chk (s, 2 - 1, __builtin_object_size (s, 2 > 1), "%02x", *data++); |
| 262 | strcpy (s, ".debug"); |
| 263 | |
| 264 | return filename; |
| 265 | } |
| 266 | |
| 267 | // Read a build ID note. Try to open any associated debuginfo file |
| 268 | // and return its symtab |
| 269 | static struct symtab* build_symtab_from_build_id(Elf64_Nhdr *note) |
| 270 | { |
| 271 | int fd; |
| 272 | struct symtab *symtab = NULL((void*)0); |
| 273 | |
| 274 | unsigned char *bytes |
| 275 | = (unsigned char*)(note+1) + note->n_namesz; |
| 276 | char *filename |
| 277 | = (build_id_to_debug_filename (note->n_descsz, bytes)); |
| 278 | if (filename == NULL((void*)0)) { |
| 279 | return NULL((void*)0); |
| 280 | } |
| 281 | fd = pathmap_open(filename); |
| 282 | if (fd >= 0) { |
| 283 | symtab = build_symtab_internal(fd, NULL((void*)0), /* try_debuginfo */ false0); |
| 284 | close(fd); |
| 285 | } |
| 286 | free(filename); |
| 287 | |
| 288 | return symtab; |
| 289 | } |
| 290 | |
| 291 | // read symbol table from given fd. If try_debuginfo) is true, also |
| 292 | // try to open an associated debuginfo file |
| 293 | static struct symtab* build_symtab_internal(int fd, const char *filename, bool try_debuginfo) { |
| 294 | ELF_EHDRElf64_Ehdr ehdr; |
| 295 | char *names = NULL((void*)0); |
| 296 | struct symtab* symtab = NULL((void*)0); |
| 297 | |
| 298 | // Reading of elf header |
| 299 | struct elf_section *scn_cache = NULL((void*)0); |
| 300 | #if defined(ppc64) && !defined(ABI_ELFv2) |
| 301 | // Only big endian ppc64 (i.e. ABI_ELFv1) has 'official procedure descriptors' in ELF files |
| 302 | // see: http://refspecs.linuxfoundation.org/LSB_3.1.1/LSB-Core-PPC64/LSB-Core-PPC64/specialsections.html |
| 303 | struct elf_section *opd_sect = NULL((void*)0); |
| 304 | ELF_SHDRElf64_Shdr *opd = NULL((void*)0); |
| 305 | #endif |
| 306 | int cnt = 0; |
| 307 | ELF_SHDRElf64_Shdr* shbuf = NULL((void*)0); |
| 308 | ELF_SHDRElf64_Shdr* cursct = NULL((void*)0); |
| 309 | ELF_PHDRElf64_Phdr* phbuf = NULL((void*)0); |
| 310 | ELF_PHDRElf64_Phdr* phdr = NULL((void*)0); |
| 311 | int sym_section = SHT_DYNSYM11; |
| 312 | |
| 313 | uintptr_t baseaddr = (uintptr_t)-1; |
| 314 | |
| 315 | lseek(fd, (off_t)0L, SEEK_SET0); |
| 316 | if (! read_elf_header(fd, &ehdr)) { |
| 317 | // not an elf |
| 318 | return NULL((void*)0); |
| 319 | } |
| 320 | |
| 321 | // read ELF header |
| 322 | if ((shbuf = read_section_header_table(fd, &ehdr)) == NULL((void*)0)) { |
| 323 | goto quit; |
| 324 | } |
| 325 | |
| 326 | baseaddr = find_base_address(fd, &ehdr); |
| 327 | |
| 328 | scn_cache = (struct elf_section *) |
| 329 | calloc(ehdr.e_shnum * sizeof(struct elf_section), 1); |
| 330 | if (scn_cache == NULL((void*)0)) { |
| 331 | goto quit; |
| 332 | } |
| 333 | |
| 334 | for (cursct = shbuf, cnt = 0; cnt < ehdr.e_shnum; cnt++) { |
| 335 | scn_cache[cnt].c_shdr = cursct; |
| 336 | if (cursct->sh_type == SHT_SYMTAB2 || cursct->sh_type == SHT_STRTAB3 |
| 337 | || cursct->sh_type == SHT_NOTE7 || cursct->sh_type == SHT_DYNSYM11) { |
| 338 | if ( (scn_cache[cnt].c_data = read_section_data(fd, &ehdr, cursct)) == NULL((void*)0)) { |
| 339 | goto quit; |
| 340 | } |
| 341 | } |
| 342 | if (cursct->sh_type == SHT_SYMTAB2) { |
| 343 | // Full symbol table available so use that |
| 344 | sym_section = cursct->sh_type; |
| 345 | } |
| 346 | cursct++; |
| 347 | } |
| 348 | |
| 349 | #if defined(ppc64) && !defined(ABI_ELFv2) |
| 350 | opd_sect = find_section_by_name(".opd", fd, &ehdr, scn_cache); |
| 351 | if (opd_sect != NULL((void*)0) && opd_sect->c_data != NULL((void*)0) && opd_sect->c_shdr != NULL((void*)0)) { |
| 352 | // plausibility check |
| 353 | opd = opd_sect->c_shdr; |
| 354 | } |
| 355 | #endif |
| 356 | |
| 357 | for (cnt = 1; cnt < ehdr.e_shnum; cnt++) { |
| 358 | ELF_SHDRElf64_Shdr *shdr = scn_cache[cnt].c_shdr; |
| 359 | |
| 360 | if (shdr->sh_type == sym_section) { |
| 361 | ELF_SYMElf64_Sym *syms; |
| 362 | int rslt; |
| 363 | size_t size, n, j, htab_sz; |
| 364 | |
| 365 | // FIXME: there could be multiple data buffers associated with the |
| 366 | // same ELF section. Here we can handle only one buffer. See man page |
| 367 | // for elf_getdata on Solaris. |
| 368 | |
| 369 | // guarantee(symtab == NULL, "multiple symtab"); |
| 370 | symtab = (struct symtab*)calloc(1, sizeof(struct symtab)); |
| 371 | if (symtab == NULL((void*)0)) { |
| 372 | goto quit; |
| 373 | } |
| 374 | // the symbol table |
| 375 | syms = (ELF_SYMElf64_Sym *)scn_cache[cnt].c_data; |
| 376 | |
| 377 | // number of symbols |
| 378 | n = shdr->sh_size / shdr->sh_entsize; |
| 379 | |
| 380 | // create hash table, we use hcreate_r, hsearch_r and hdestroy_r to |
| 381 | // manipulate the hash table. |
| 382 | |
| 383 | // NOTES section in the man page of hcreate_r says |
| 384 | // "Hash table implementations are usually more efficient when |
| 385 | // the table contains enough free space to minimize collisions. |
| 386 | // Typically, this means that nel should be at least 25% larger |
| 387 | // than the maximum number of elements that the caller expects |
| 388 | // to store in the table." |
| 389 | htab_sz = n*1.25; |
Value stored to 'htab_sz' is never read | |
| 390 | |
| 391 | symtab->hash_table = (struct hsearch_data*) calloc(1, sizeof(struct hsearch_data)); |
| 392 | if (symtab->hash_table == NULL((void*)0)) { |
| 393 | goto bad; |
| 394 | } |
| 395 | |
| 396 | rslt = hcreate_r(n, symtab->hash_table); |
| 397 | // guarantee(rslt, "unexpected failure: hcreate_r"); |
| 398 | |
| 399 | // shdr->sh_link points to the section that contains the actual strings |
| 400 | // for symbol names. the st_name field in ELF_SYM is just the |
| 401 | // string table index. we make a copy of the string table so the |
| 402 | // strings will not be destroyed by elf_end. |
| 403 | size = scn_cache[shdr->sh_link].c_shdr->sh_size; |
| 404 | symtab->strs = (char *)malloc(size); |
| 405 | if (symtab->strs == NULL((void*)0)) { |
| 406 | goto bad; |
| 407 | } |
| 408 | memcpy(symtab->strs, scn_cache[shdr->sh_link].c_data, size); |
| 409 | |
| 410 | // allocate memory for storing symbol offset and size; |
| 411 | symtab->num_symbols = n; |
| 412 | symtab->symbols = (struct elf_symbol *)calloc(n , sizeof(struct elf_symbol)); |
| 413 | if (symtab->symbols == NULL((void*)0)) { |
| 414 | goto bad; |
| 415 | } |
| 416 | |
| 417 | // copy symbols info our symtab and enter them info the hash table |
| 418 | for (j = 0; j < n; j++, syms++) { |
| 419 | ENTRY item, *ret; |
| 420 | uintptr_t sym_value; |
| 421 | char *sym_name = symtab->strs + syms->st_name; |
| 422 | |
| 423 | // skip non-object and non-function symbols |
| 424 | int st_type = ELF_ST_TYPE(syms->st_info)((syms->st_info) & 0xf); |
| 425 | if ( st_type != STT_FUNC2 && st_type != STT_OBJECT1) |
| 426 | continue; |
| 427 | // skip empty strings and undefined symbols |
| 428 | if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF0) continue; |
| 429 | |
| 430 | symtab->symbols[j].name = sym_name; |
| 431 | symtab->symbols[j].size = syms->st_size; |
| 432 | sym_value = syms->st_value; |
| 433 | |
| 434 | #if defined(ppc64) && !defined(ABI_ELFv2) |
| 435 | // see hotspot/src/share/vm/utilities/elfFuncDescTable.hpp for a detailed description |
| 436 | // of why we have to go this extra way via the '.opd' section on big endian ppc64 |
| 437 | if (opd != NULL((void*)0) && *sym_name != '.' && |
| 438 | (opd->sh_addr <= sym_value && sym_value <= opd->sh_addr + opd->sh_size)) { |
| 439 | sym_value = ((ELF_ADDRElf64_Addr*)opd_sect->c_data)[(sym_value - opd->sh_addr) / sizeof(ELF_ADDRElf64_Addr*)]; |
| 440 | } |
| 441 | #endif |
| 442 | |
| 443 | symtab->symbols[j].offset = sym_value - baseaddr; |
| 444 | item.key = sym_name; |
| 445 | item.data = (void *)&(symtab->symbols[j]); |
| 446 | hsearch_r(item, ENTER, &ret, symtab->hash_table); |
| 447 | } |
| 448 | } |
| 449 | } |
| 450 | |
| 451 | #if defined(ppc64) && !defined(ABI_ELFv2) |
| 452 | // On Linux/PPC64 the debuginfo files contain an empty function descriptor |
| 453 | // section (i.e. '.opd' section) which makes the resolution of symbols |
| 454 | // with the above algorithm impossible (we would need the have both, the |
| 455 | // .opd section from the library and the symbol table from the debuginfo |
| 456 | // file which doesn't match with the current workflow.) |
| 457 | goto quit; |
| 458 | #endif |
| 459 | |
| 460 | // Look for a separate debuginfo file. |
| 461 | if (try_debuginfo) { |
| 462 | // We prefer a debug symtab to an object's own symtab, so look in |
| 463 | // the debuginfo file. We stash a copy of the old symtab in case |
| 464 | // there is no debuginfo. |
| 465 | struct symtab* prev_symtab = symtab; |
| 466 | symtab = NULL((void*)0); |
| 467 | |
| 468 | #ifdef NT_GNU_BUILD_ID3 |
| 469 | // First we look for a Build ID |
| 470 | for (cursct = shbuf, cnt = 0; |
| 471 | symtab == NULL((void*)0) && cnt < ehdr.e_shnum; |
| 472 | cnt++) { |
| 473 | if (cursct->sh_type == SHT_NOTE7) { |
| 474 | Elf64_Nhdr *note = (Elf64_Nhdr *)scn_cache[cnt].c_data; |
| 475 | if (note->n_type == NT_GNU_BUILD_ID3) { |
| 476 | symtab = build_symtab_from_build_id(note); |
| 477 | } |
| 478 | } |
| 479 | cursct++; |
| 480 | } |
| 481 | #endif |
| 482 | |
| 483 | // Then, if that doesn't work, the debug link |
| 484 | if (symtab == NULL((void*)0)) { |
| 485 | symtab = build_symtab_from_debug_link(filename, fd, &ehdr, |
| 486 | scn_cache); |
| 487 | } |
| 488 | |
| 489 | // If we still haven't found a symtab, use the object's own symtab. |
| 490 | if (symtab != NULL((void*)0)) { |
| 491 | if (prev_symtab != NULL((void*)0)) |
| 492 | destroy_symtab(prev_symtab); |
| 493 | } else { |
| 494 | symtab = prev_symtab; |
| 495 | } |
| 496 | } |
| 497 | goto quit; |
| 498 | |
| 499 | bad: |
| 500 | destroy_symtab(symtab); |
| 501 | symtab = NULL((void*)0); |
| 502 | |
| 503 | quit: |
| 504 | if (shbuf) free(shbuf); |
| 505 | if (phbuf) free(phbuf); |
| 506 | if (scn_cache) { |
| 507 | for (cnt = 0; cnt < ehdr.e_shnum; cnt++) { |
| 508 | if (scn_cache[cnt].c_data != NULL((void*)0)) { |
| 509 | free(scn_cache[cnt].c_data); |
| 510 | } |
| 511 | } |
| 512 | free(scn_cache); |
| 513 | } |
| 514 | return symtab; |
| 515 | } |
| 516 | |
| 517 | struct symtab* build_symtab(int fd, const char *filename) { |
| 518 | return build_symtab_internal(fd, filename, /* try_debuginfo */ true1); |
| 519 | } |
| 520 | |
| 521 | |
| 522 | void destroy_symtab(struct symtab* symtab) { |
| 523 | if (!symtab) return; |
| 524 | if (symtab->strs) free(symtab->strs); |
| 525 | if (symtab->symbols) free(symtab->symbols); |
| 526 | if (symtab->hash_table) { |
| 527 | hdestroy_r(symtab->hash_table); |
| 528 | free(symtab->hash_table); |
| 529 | } |
| 530 | free(symtab); |
| 531 | } |
| 532 | |
| 533 | uintptr_t search_symbol(struct symtab* symtab, uintptr_t base, |
| 534 | const char *sym_name, int *sym_size) { |
| 535 | ENTRY item; |
| 536 | ENTRY* ret = NULL((void*)0); |
| 537 | |
| 538 | // library does not have symbol table |
| 539 | if (!symtab || !symtab->hash_table) |
| 540 | return (uintptr_t)NULL((void*)0); |
| 541 | |
| 542 | item.key = (char*) strdup(sym_name); |
| 543 | item.data = NULL((void*)0); |
| 544 | hsearch_r(item, FIND, &ret, symtab->hash_table); |
| 545 | if (ret) { |
| 546 | struct elf_symbol * sym = (struct elf_symbol *)(ret->data); |
| 547 | uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset); |
| 548 | if (sym_size) *sym_size = sym->size; |
| 549 | free(item.key); |
| 550 | return rslt; |
| 551 | } |
| 552 | |
| 553 | quit: |
| 554 | free(item.key); |
| 555 | return (uintptr_t) NULL((void*)0); |
| 556 | } |
| 557 | |
| 558 | const char* nearest_symbol(struct symtab* symtab, uintptr_t offset, |
| 559 | uintptr_t* poffset) { |
| 560 | int n = 0; |
| 561 | if (!symtab) return NULL((void*)0); |
| 562 | for (; n < symtab->num_symbols; n++) { |
| 563 | struct elf_symbol* sym = &(symtab->symbols[n]); |
| 564 | if (sym->name != NULL((void*)0) && |
| 565 | offset >= sym->offset && offset < sym->offset + sym->size) { |
| 566 | if (poffset) *poffset = (offset - sym->offset); |
| 567 | return sym->name; |
| 568 | } |
| 569 | } |
| 570 | return NULL((void*)0); |
| 571 | } |