tools/perf/util/symbol-minimal.c

   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 }