1 #include "dso.h"
2 #include "symbol.h"
3 #include "symsrc.h"
4
5 #include <errno.h>
6 #include <unistd.h>
7 #include <fcntl.h>
8 #include <string.h>
9 #include <stdlib.h>
10 #include <byteswap.h>
11 #include <sys/stat.h>
12 #include <linux/zalloc.h>
13 #include <internal/lib.h>
14
check_need_swap(int file_endian)15 static bool check_need_swap(int file_endian)
16 {
17 const int data = 1;
18 u8 *check = (u8 *)&data;
19 int host_endian;
20
21 if (check[0] == 1)
22 host_endian = ELFDATA2LSB;
23 else
24 host_endian = ELFDATA2MSB;
25
26 return host_endian != file_endian;
27 }
28
29 #define NOTE_ALIGN(sz) (((sz) + 3) & ~3)
30
31 #define NT_GNU_BUILD_ID 3
32
read_build_id(void * note_data,size_t note_len,struct build_id * bid,bool need_swap)33 static int read_build_id(void *note_data, size_t note_len, struct build_id *bid,
34 bool need_swap)
35 {
36 size_t size = sizeof(bid->data);
37 struct {
38 u32 n_namesz;
39 u32 n_descsz;
40 u32 n_type;
41 } *nhdr;
42 void *ptr;
43
44 ptr = note_data;
45 while (ptr < (note_data + note_len)) {
46 const char *name;
47 size_t namesz, descsz;
48
49 nhdr = ptr;
50 if (need_swap) {
51 nhdr->n_namesz = bswap_32(nhdr->n_namesz);
52 nhdr->n_descsz = bswap_32(nhdr->n_descsz);
53 nhdr->n_type = bswap_32(nhdr->n_type);
54 }
55
56 namesz = NOTE_ALIGN(nhdr->n_namesz);
57 descsz = NOTE_ALIGN(nhdr->n_descsz);
58
59 ptr += sizeof(*nhdr);
60 name = ptr;
61 ptr += namesz;
62 if (nhdr->n_type == NT_GNU_BUILD_ID &&
63 nhdr->n_namesz == sizeof("GNU")) {
64 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
65 size_t sz = min(size, descsz);
66 memcpy(bid->data, ptr, sz);
67 memset(bid->data + sz, 0, size - sz);
68 bid->size = sz;
69 return 0;
70 }
71 }
72 ptr += descsz;
73 }
74
75 return -1;
76 }
77
filename__read_debuglink(const char * filename __maybe_unused,char * debuglink __maybe_unused,size_t size __maybe_unused)78 int filename__read_debuglink(const char *filename __maybe_unused,
79 char *debuglink __maybe_unused,
80 size_t size __maybe_unused)
81 {
82 return -1;
83 }
84
85 /*
86 * Just try PT_NOTE header otherwise fails
87 */
filename__read_build_id(const char * filename,struct build_id * bid,bool block)88 int filename__read_build_id(const char *filename, struct build_id *bid, bool block)
89 {
90 int fd, ret = -1;
91 bool need_swap = false, elf32;
92 union {
93 struct {
94 Elf32_Ehdr ehdr32;
95 Elf32_Phdr *phdr32;
96 };
97 struct {
98 Elf64_Ehdr ehdr64;
99 Elf64_Phdr *phdr64;
100 };
101 } hdrs;
102 void *phdr, *buf = NULL;
103 ssize_t phdr_size, ehdr_size, buf_size = 0;
104
105 fd = open(filename, block ? O_RDONLY : (O_RDONLY | O_NONBLOCK));
106 if (fd < 0)
107 return -1;
108
109 if (read(fd, hdrs.ehdr32.e_ident, EI_NIDENT) != EI_NIDENT)
110 goto out;
111
112 if (memcmp(hdrs.ehdr32.e_ident, ELFMAG, SELFMAG) ||
113 hdrs.ehdr32.e_ident[EI_VERSION] != EV_CURRENT)
114 goto out;
115
116 need_swap = check_need_swap(hdrs.ehdr32.e_ident[EI_DATA]);
117 elf32 = hdrs.ehdr32.e_ident[EI_CLASS] == ELFCLASS32;
118 ehdr_size = (elf32 ? sizeof(hdrs.ehdr32) : sizeof(hdrs.ehdr64)) - EI_NIDENT;
119
120 if (read(fd,
121 (elf32 ? (void *)&hdrs.ehdr32 : (void *)&hdrs.ehdr64) + EI_NIDENT,
122 ehdr_size) != ehdr_size)
123 goto out;
124
125 if (need_swap) {
126 if (elf32) {
127 hdrs.ehdr32.e_phoff = bswap_32(hdrs.ehdr32.e_phoff);
128 hdrs.ehdr32.e_phentsize = bswap_16(hdrs.ehdr32.e_phentsize);
129 hdrs.ehdr32.e_phnum = bswap_16(hdrs.ehdr32.e_phnum);
130 } else {
131 hdrs.ehdr64.e_phoff = bswap_64(hdrs.ehdr64.e_phoff);
132 hdrs.ehdr64.e_phentsize = bswap_16(hdrs.ehdr64.e_phentsize);
133 hdrs.ehdr64.e_phnum = bswap_16(hdrs.ehdr64.e_phnum);
134 }
135 }
136 if ((elf32 && hdrs.ehdr32.e_phentsize != sizeof(Elf32_Phdr)) ||
137 (!elf32 && hdrs.ehdr64.e_phentsize != sizeof(Elf64_Phdr)))
138 goto out;
139
140 phdr_size = elf32 ? sizeof(Elf32_Phdr) * hdrs.ehdr32.e_phnum
141 : sizeof(Elf64_Phdr) * hdrs.ehdr64.e_phnum;
142 phdr = malloc(phdr_size);
143 if (phdr == NULL)
144 goto out;
145
146 lseek(fd, elf32 ? hdrs.ehdr32.e_phoff : hdrs.ehdr64.e_phoff, SEEK_SET);
147 if (read(fd, phdr, phdr_size) != phdr_size)
148 goto out_free;
149
150 if (elf32)
151 hdrs.phdr32 = phdr;
152 else
153 hdrs.phdr64 = phdr;
154
155 for (int i = 0; i < (elf32 ? hdrs.ehdr32.e_phnum : hdrs.ehdr64.e_phnum); i++) {
156 ssize_t p_filesz;
157
158 if (need_swap) {
159 if (elf32) {
160 hdrs.phdr32[i].p_type = bswap_32(hdrs.phdr32[i].p_type);
161 hdrs.phdr32[i].p_offset = bswap_32(hdrs.phdr32[i].p_offset);
162 hdrs.phdr32[i].p_filesz = bswap_32(hdrs.phdr32[i].p_offset);
163 } else {
164 hdrs.phdr64[i].p_type = bswap_32(hdrs.phdr64[i].p_type);
165 hdrs.phdr64[i].p_offset = bswap_64(hdrs.phdr64[i].p_offset);
166 hdrs.phdr64[i].p_filesz = bswap_64(hdrs.phdr64[i].p_filesz);
167 }
168 }
169 if ((elf32 ? hdrs.phdr32[i].p_type : hdrs.phdr64[i].p_type) != PT_NOTE)
170 continue;
171
172 p_filesz = elf32 ? hdrs.phdr32[i].p_filesz : hdrs.phdr64[i].p_filesz;
173 if (p_filesz > buf_size) {
174 void *tmp;
175
176 buf_size = p_filesz;
177 tmp = realloc(buf, buf_size);
178 if (tmp == NULL)
179 goto out_free;
180 buf = tmp;
181 }
182 lseek(fd, elf32 ? hdrs.phdr32[i].p_offset : hdrs.phdr64[i].p_offset, SEEK_SET);
183 if (read(fd, buf, p_filesz) != p_filesz)
184 goto out_free;
185
186 ret = read_build_id(buf, p_filesz, bid, need_swap);
187 if (ret == 0) {
188 ret = bid->size;
189 break;
190 }
191 }
192 out_free:
193 free(buf);
194 free(phdr);
195 out:
196 close(fd);
197 return ret;
198 }
199
sysfs__read_build_id(const char * filename,struct build_id * bid)200 int sysfs__read_build_id(const char *filename, struct build_id *bid)
201 {
202 int fd;
203 int ret = -1;
204 struct stat stbuf;
205 size_t buf_size;
206 void *buf;
207
208 fd = open(filename, O_RDONLY);
209 if (fd < 0)
210 return -1;
211
212 if (fstat(fd, &stbuf) < 0)
213 goto out;
214
215 buf_size = stbuf.st_size;
216 buf = malloc(buf_size);
217 if (buf == NULL)
218 goto out;
219
220 if (read(fd, buf, buf_size) != (ssize_t) buf_size)
221 goto out_free;
222
223 ret = read_build_id(buf, buf_size, bid, false);
224 out_free:
225 free(buf);
226 out:
227 close(fd);
228 return ret;
229 }
230
symsrc__init(struct symsrc * ss,struct dso * dso,const char * name,enum dso_binary_type type)231 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
232 enum dso_binary_type type)
233 {
234 int fd = open(name, O_RDONLY);
235 if (fd < 0)
236 goto out_errno;
237
238 ss->name = strdup(name);
239 if (!ss->name)
240 goto out_close;
241
242 ss->fd = fd;
243 ss->type = type;
244
245 return 0;
246 out_close:
247 close(fd);
248 out_errno:
249 RC_CHK_ACCESS(dso)->load_errno = errno;
250 return -1;
251 }
252
symsrc__possibly_runtime(struct symsrc * ss __maybe_unused)253 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
254 {
255 /* Assume all sym sources could be a runtime image. */
256 return true;
257 }
258
symsrc__has_symtab(struct symsrc * ss __maybe_unused)259 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
260 {
261 return false;
262 }
263
symsrc__destroy(struct symsrc * ss)264 void symsrc__destroy(struct symsrc *ss)
265 {
266 zfree(&ss->name);
267 close(ss->fd);
268 }
269
dso__synthesize_plt_symbols(struct dso * dso __maybe_unused,struct symsrc * ss __maybe_unused)270 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
271 struct symsrc *ss __maybe_unused)
272 {
273 return 0;
274 }
275
fd__is_64_bit(int fd)276 static int fd__is_64_bit(int fd)
277 {
278 u8 e_ident[EI_NIDENT];
279
280 if (lseek(fd, 0, SEEK_SET))
281 return -1;
282
283 if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident))
284 return -1;
285
286 if (memcmp(e_ident, ELFMAG, SELFMAG) ||
287 e_ident[EI_VERSION] != EV_CURRENT)
288 return -1;
289
290 return e_ident[EI_CLASS] == ELFCLASS64;
291 }
292
dso__type_fd(int fd)293 enum dso_type dso__type_fd(int fd)
294 {
295 Elf64_Ehdr ehdr;
296 int ret;
297
298 ret = fd__is_64_bit(fd);
299 if (ret < 0)
300 return DSO__TYPE_UNKNOWN;
301
302 if (ret)
303 return DSO__TYPE_64BIT;
304
305 if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
306 return DSO__TYPE_UNKNOWN;
307
308 if (ehdr.e_machine == EM_X86_64)
309 return DSO__TYPE_X32BIT;
310
311 return DSO__TYPE_32BIT;
312 }
313
dso__load_sym(struct dso * dso,struct map * map __maybe_unused,struct symsrc * ss,struct symsrc * runtime_ss __maybe_unused,int kmodule __maybe_unused)314 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
315 struct symsrc *ss,
316 struct symsrc *runtime_ss __maybe_unused,
317 int kmodule __maybe_unused)
318 {
319 struct build_id bid = { .size = 0, };
320 int ret;
321
322 ret = fd__is_64_bit(ss->fd);
323 if (ret >= 0)
324 RC_CHK_ACCESS(dso)->is_64_bit = ret;
325
326 if (filename__read_build_id(ss->name, &bid, /*block=*/true) > 0)
327 dso__set_build_id(dso, &bid);
328 return 0;
329 }
330
file__read_maps(int fd __maybe_unused,bool exe __maybe_unused,mapfn_t mapfn __maybe_unused,void * data __maybe_unused,bool * is_64_bit __maybe_unused)331 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused,
332 mapfn_t mapfn __maybe_unused, void *data __maybe_unused,
333 bool *is_64_bit __maybe_unused)
334 {
335 return -1;
336 }
337
kcore_extract__create(struct kcore_extract * kce __maybe_unused)338 int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
339 {
340 return -1;
341 }
342
kcore_extract__delete(struct kcore_extract * kce __maybe_unused)343 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
344 {
345 }
346
kcore_copy(const char * from_dir __maybe_unused,const char * to_dir __maybe_unused)347 int kcore_copy(const char *from_dir __maybe_unused,
348 const char *to_dir __maybe_unused)
349 {
350 return -1;
351 }
352
symbol__elf_init(void)353 void symbol__elf_init(void)
354 {
355 }
356
filename__has_section(const char * filename __maybe_unused,const char * sec __maybe_unused)357 bool filename__has_section(const char *filename __maybe_unused, const char *sec __maybe_unused)
358 {
359 return false;
360 }
361