1 #include "symbol.h" 2 3 #include <elf.h> 4 #include <stdio.h> 5 #include <fcntl.h> 6 #include <string.h> 7 #include <byteswap.h> 8 #include <sys/stat.h> 9 10 11 static bool check_need_swap(int file_endian) 12 { 13 const int data = 1; 14 u8 *check = (u8 *)&data; 15 int host_endian; 16 17 if (check[0] == 1) 18 host_endian = ELFDATA2LSB; 19 else 20 host_endian = ELFDATA2MSB; 21 22 return host_endian != file_endian; 23 } 24 25 #define NOTE_ALIGN(sz) (((sz) + 3) & ~3) 26 27 #define NT_GNU_BUILD_ID 3 28 29 static int read_build_id(void *note_data, size_t note_len, void *bf, 30 size_t size, bool need_swap) 31 { 32 struct { 33 u32 n_namesz; 34 u32 n_descsz; 35 u32 n_type; 36 } *nhdr; 37 void *ptr; 38 39 ptr = note_data; 40 while (ptr < (note_data + note_len)) { 41 const char *name; 42 size_t namesz, descsz; 43 44 nhdr = ptr; 45 if (need_swap) { 46 nhdr->n_namesz = bswap_32(nhdr->n_namesz); 47 nhdr->n_descsz = bswap_32(nhdr->n_descsz); 48 nhdr->n_type = bswap_32(nhdr->n_type); 49 } 50 51 namesz = NOTE_ALIGN(nhdr->n_namesz); 52 descsz = NOTE_ALIGN(nhdr->n_descsz); 53 54 ptr += sizeof(*nhdr); 55 name = ptr; 56 ptr += namesz; 57 if (nhdr->n_type == NT_GNU_BUILD_ID && 58 nhdr->n_namesz == sizeof("GNU")) { 59 if (memcmp(name, "GNU", sizeof("GNU")) == 0) { 60 size_t sz = min(size, descsz); 61 memcpy(bf, ptr, sz); 62 memset(bf + sz, 0, size - sz); 63 return 0; 64 } 65 } 66 ptr += descsz; 67 } 68 69 return -1; 70 } 71 72 int filename__read_debuglink(const char *filename __maybe_unused, 73 char *debuglink __maybe_unused, 74 size_t size __maybe_unused) 75 { 76 return -1; 77 } 78 79 /* 80 * Just try PT_NOTE header otherwise fails 81 */ 82 int filename__read_build_id(const char *filename, void *bf, size_t size) 83 { 84 FILE *fp; 85 int ret = -1; 86 bool need_swap = false; 87 u8 e_ident[EI_NIDENT]; 88 size_t buf_size; 89 void *buf; 90 int i; 91 92 fp = fopen(filename, "r"); 93 if (fp == NULL) 94 return -1; 95 96 if (fread(e_ident, sizeof(e_ident), 1, fp) != 1) 97 goto out; 98 99 if (memcmp(e_ident, ELFMAG, SELFMAG) || 100 e_ident[EI_VERSION] != EV_CURRENT) 101 goto out; 102 103 need_swap = check_need_swap(e_ident[EI_DATA]); 104 105 /* for simplicity */ 106 fseek(fp, 0, SEEK_SET); 107 108 if (e_ident[EI_CLASS] == ELFCLASS32) { 109 Elf32_Ehdr ehdr; 110 Elf32_Phdr *phdr; 111 112 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) 113 goto out; 114 115 if (need_swap) { 116 ehdr.e_phoff = bswap_32(ehdr.e_phoff); 117 ehdr.e_phentsize = bswap_16(ehdr.e_phentsize); 118 ehdr.e_phnum = bswap_16(ehdr.e_phnum); 119 } 120 121 buf_size = ehdr.e_phentsize * ehdr.e_phnum; 122 buf = malloc(buf_size); 123 if (buf == NULL) 124 goto out; 125 126 fseek(fp, ehdr.e_phoff, SEEK_SET); 127 if (fread(buf, buf_size, 1, fp) != 1) 128 goto out_free; 129 130 for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { 131 void *tmp; 132 133 if (need_swap) { 134 phdr->p_type = bswap_32(phdr->p_type); 135 phdr->p_offset = bswap_32(phdr->p_offset); 136 phdr->p_filesz = bswap_32(phdr->p_filesz); 137 } 138 139 if (phdr->p_type != PT_NOTE) 140 continue; 141 142 buf_size = phdr->p_filesz; 143 tmp = realloc(buf, buf_size); 144 if (tmp == NULL) 145 goto out_free; 146 147 buf = tmp; 148 fseek(fp, phdr->p_offset, SEEK_SET); 149 if (fread(buf, buf_size, 1, fp) != 1) 150 goto out_free; 151 152 ret = read_build_id(buf, buf_size, bf, size, need_swap); 153 if (ret == 0) 154 ret = size; 155 break; 156 } 157 } else { 158 Elf64_Ehdr ehdr; 159 Elf64_Phdr *phdr; 160 161 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) 162 goto out; 163 164 if (need_swap) { 165 ehdr.e_phoff = bswap_64(ehdr.e_phoff); 166 ehdr.e_phentsize = bswap_16(ehdr.e_phentsize); 167 ehdr.e_phnum = bswap_16(ehdr.e_phnum); 168 } 169 170 buf_size = ehdr.e_phentsize * ehdr.e_phnum; 171 buf = malloc(buf_size); 172 if (buf == NULL) 173 goto out; 174 175 fseek(fp, ehdr.e_phoff, SEEK_SET); 176 if (fread(buf, buf_size, 1, fp) != 1) 177 goto out_free; 178 179 for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { 180 void *tmp; 181 182 if (need_swap) { 183 phdr->p_type = bswap_32(phdr->p_type); 184 phdr->p_offset = bswap_64(phdr->p_offset); 185 phdr->p_filesz = bswap_64(phdr->p_filesz); 186 } 187 188 if (phdr->p_type != PT_NOTE) 189 continue; 190 191 buf_size = phdr->p_filesz; 192 tmp = realloc(buf, buf_size); 193 if (tmp == NULL) 194 goto out_free; 195 196 buf = tmp; 197 fseek(fp, phdr->p_offset, SEEK_SET); 198 if (fread(buf, buf_size, 1, fp) != 1) 199 goto out_free; 200 201 ret = read_build_id(buf, buf_size, bf, size, need_swap); 202 if (ret == 0) 203 ret = size; 204 break; 205 } 206 } 207 out_free: 208 free(buf); 209 out: 210 fclose(fp); 211 return ret; 212 } 213 214 int sysfs__read_build_id(const char *filename, void *build_id, size_t size) 215 { 216 int fd; 217 int ret = -1; 218 struct stat stbuf; 219 size_t buf_size; 220 void *buf; 221 222 fd = open(filename, O_RDONLY); 223 if (fd < 0) 224 return -1; 225 226 if (fstat(fd, &stbuf) < 0) 227 goto out; 228 229 buf_size = stbuf.st_size; 230 buf = malloc(buf_size); 231 if (buf == NULL) 232 goto out; 233 234 if (read(fd, buf, buf_size) != (ssize_t) buf_size) 235 goto out_free; 236 237 ret = read_build_id(buf, buf_size, build_id, size, false); 238 out_free: 239 free(buf); 240 out: 241 close(fd); 242 return ret; 243 } 244 245 int symsrc__init(struct symsrc *ss, struct dso *dso __maybe_unused, 246 const char *name, 247 enum dso_binary_type type) 248 { 249 int fd = open(name, O_RDONLY); 250 if (fd < 0) 251 return -1; 252 253 ss->name = strdup(name); 254 if (!ss->name) 255 goto out_close; 256 257 ss->type = type; 258 259 return 0; 260 out_close: 261 close(fd); 262 return -1; 263 } 264 265 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused) 266 { 267 /* Assume all sym sources could be a runtime image. */ 268 return true; 269 } 270 271 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused) 272 { 273 return false; 274 } 275 276 void symsrc__destroy(struct symsrc *ss) 277 { 278 free(ss->name); 279 close(ss->fd); 280 } 281 282 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused, 283 struct symsrc *ss __maybe_unused, 284 struct map *map __maybe_unused, 285 symbol_filter_t filter __maybe_unused) 286 { 287 return 0; 288 } 289 290 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused, 291 struct symsrc *ss, 292 struct symsrc *runtime_ss __maybe_unused, 293 symbol_filter_t filter __maybe_unused, 294 int kmodule __maybe_unused) 295 { 296 unsigned char *build_id[BUILD_ID_SIZE]; 297 298 if (filename__read_build_id(ss->name, build_id, BUILD_ID_SIZE) > 0) { 299 dso__set_build_id(dso, build_id); 300 return 1; 301 } 302 return 0; 303 } 304 305 void symbol__elf_init(void) 306 { 307 } 308