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 + sizeof(*nhdr)) < (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)88 int filename__read_build_id(const char *filename, struct build_id *bid)
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 if (!filename)
106 return -EFAULT;
107 if (!is_regular_file(filename))
108 return -EWOULDBLOCK;
109
110 fd = open(filename, O_RDONLY);
111 if (fd < 0)
112 return -1;
113
114 if (read(fd, hdrs.ehdr32.e_ident, EI_NIDENT) != EI_NIDENT)
115 goto out;
116
117 if (memcmp(hdrs.ehdr32.e_ident, ELFMAG, SELFMAG) ||
118 hdrs.ehdr32.e_ident[EI_VERSION] != EV_CURRENT)
119 goto out;
120
121 need_swap = check_need_swap(hdrs.ehdr32.e_ident[EI_DATA]);
122 elf32 = hdrs.ehdr32.e_ident[EI_CLASS] == ELFCLASS32;
123 ehdr_size = (elf32 ? sizeof(hdrs.ehdr32) : sizeof(hdrs.ehdr64)) - EI_NIDENT;
124
125 if (read(fd,
126 (elf32 ? (void *)&hdrs.ehdr32 : (void *)&hdrs.ehdr64) + EI_NIDENT,
127 ehdr_size) != ehdr_size)
128 goto out;
129
130 if (need_swap) {
131 if (elf32) {
132 hdrs.ehdr32.e_phoff = bswap_32(hdrs.ehdr32.e_phoff);
133 hdrs.ehdr32.e_phentsize = bswap_16(hdrs.ehdr32.e_phentsize);
134 hdrs.ehdr32.e_phnum = bswap_16(hdrs.ehdr32.e_phnum);
135 } else {
136 hdrs.ehdr64.e_phoff = bswap_64(hdrs.ehdr64.e_phoff);
137 hdrs.ehdr64.e_phentsize = bswap_16(hdrs.ehdr64.e_phentsize);
138 hdrs.ehdr64.e_phnum = bswap_16(hdrs.ehdr64.e_phnum);
139 }
140 }
141 if ((elf32 && hdrs.ehdr32.e_phentsize != sizeof(Elf32_Phdr)) ||
142 (!elf32 && hdrs.ehdr64.e_phentsize != sizeof(Elf64_Phdr)))
143 goto out;
144
145 phdr_size = elf32 ? sizeof(Elf32_Phdr) * hdrs.ehdr32.e_phnum
146 : sizeof(Elf64_Phdr) * hdrs.ehdr64.e_phnum;
147 phdr = malloc(phdr_size);
148 if (phdr == NULL)
149 goto out;
150
151 lseek(fd, elf32 ? hdrs.ehdr32.e_phoff : hdrs.ehdr64.e_phoff, SEEK_SET);
152 if (read(fd, phdr, phdr_size) != phdr_size)
153 goto out_free;
154
155 if (elf32)
156 hdrs.phdr32 = phdr;
157 else
158 hdrs.phdr64 = phdr;
159
160 for (int i = 0; i < (elf32 ? hdrs.ehdr32.e_phnum : hdrs.ehdr64.e_phnum); i++) {
161 ssize_t p_filesz;
162
163 if (need_swap) {
164 if (elf32) {
165 hdrs.phdr32[i].p_type = bswap_32(hdrs.phdr32[i].p_type);
166 hdrs.phdr32[i].p_offset = bswap_32(hdrs.phdr32[i].p_offset);
167 hdrs.phdr32[i].p_filesz = bswap_32(hdrs.phdr32[i].p_offset);
168 } else {
169 hdrs.phdr64[i].p_type = bswap_32(hdrs.phdr64[i].p_type);
170 hdrs.phdr64[i].p_offset = bswap_64(hdrs.phdr64[i].p_offset);
171 hdrs.phdr64[i].p_filesz = bswap_64(hdrs.phdr64[i].p_filesz);
172 }
173 }
174 if ((elf32 ? hdrs.phdr32[i].p_type : hdrs.phdr64[i].p_type) != PT_NOTE)
175 continue;
176
177 p_filesz = elf32 ? hdrs.phdr32[i].p_filesz : hdrs.phdr64[i].p_filesz;
178 if (p_filesz > buf_size) {
179 void *tmp;
180
181 buf_size = p_filesz;
182 tmp = realloc(buf, buf_size);
183 if (tmp == NULL)
184 goto out_free;
185 buf = tmp;
186 }
187 lseek(fd, elf32 ? hdrs.phdr32[i].p_offset : hdrs.phdr64[i].p_offset, SEEK_SET);
188 if (read(fd, buf, p_filesz) != p_filesz)
189 goto out_free;
190
191 ret = read_build_id(buf, p_filesz, bid, need_swap);
192 if (ret == 0) {
193 ret = bid->size;
194 break;
195 }
196 }
197 out_free:
198 free(buf);
199 free(phdr);
200 out:
201 close(fd);
202 return ret;
203 }
204
sysfs__read_build_id(const char * filename,struct build_id * bid)205 int sysfs__read_build_id(const char *filename, struct build_id *bid)
206 {
207 int fd;
208 int ret = -1;
209 struct stat stbuf;
210 size_t buf_size;
211 void *buf;
212
213 fd = open(filename, O_RDONLY);
214 if (fd < 0)
215 return -1;
216
217 if (fstat(fd, &stbuf) < 0)
218 goto out;
219
220 buf_size = stbuf.st_size;
221 buf = malloc(buf_size);
222 if (buf == NULL)
223 goto out;
224
225 if (read(fd, buf, buf_size) != (ssize_t) buf_size)
226 goto out_free;
227
228 ret = read_build_id(buf, buf_size, bid, false);
229 out_free:
230 free(buf);
231 out:
232 close(fd);
233 return ret;
234 }
235
symsrc__init(struct symsrc * ss,struct dso * dso,const char * name,enum dso_binary_type type)236 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
237 enum dso_binary_type type)
238 {
239 int fd = open(name, O_RDONLY);
240 if (fd < 0)
241 goto out_errno;
242
243 ss->name = strdup(name);
244 if (!ss->name)
245 goto out_close;
246
247 ss->fd = fd;
248 ss->type = type;
249
250 return 0;
251 out_close:
252 close(fd);
253 out_errno:
254 RC_CHK_ACCESS(dso)->load_errno = errno;
255 return -1;
256 }
257
symsrc__possibly_runtime(struct symsrc * ss __maybe_unused)258 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
259 {
260 /* Assume all sym sources could be a runtime image. */
261 return true;
262 }
263
symsrc__has_symtab(struct symsrc * ss __maybe_unused)264 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
265 {
266 return false;
267 }
268
symsrc__destroy(struct symsrc * ss)269 void symsrc__destroy(struct symsrc *ss)
270 {
271 zfree(&ss->name);
272 close(ss->fd);
273 }
274
dso__synthesize_plt_symbols(struct dso * dso __maybe_unused,struct symsrc * ss __maybe_unused)275 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
276 struct symsrc *ss __maybe_unused)
277 {
278 return 0;
279 }
280
fd__is_64_bit(int fd)281 static int fd__is_64_bit(int fd)
282 {
283 u8 e_ident[EI_NIDENT];
284
285 if (lseek(fd, 0, SEEK_SET))
286 return -1;
287
288 if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident))
289 return -1;
290
291 if (memcmp(e_ident, ELFMAG, SELFMAG) ||
292 e_ident[EI_VERSION] != EV_CURRENT)
293 return -1;
294
295 return e_ident[EI_CLASS] == ELFCLASS64;
296 }
297
dso__type_fd(int fd)298 enum dso_type dso__type_fd(int fd)
299 {
300 Elf64_Ehdr ehdr;
301 int ret;
302
303 ret = fd__is_64_bit(fd);
304 if (ret < 0)
305 return DSO__TYPE_UNKNOWN;
306
307 if (ret)
308 return DSO__TYPE_64BIT;
309
310 if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
311 return DSO__TYPE_UNKNOWN;
312
313 if (ehdr.e_machine == EM_X86_64)
314 return DSO__TYPE_X32BIT;
315
316 return DSO__TYPE_32BIT;
317 }
318
dso__load_sym(struct dso * dso,struct map * map __maybe_unused,struct symsrc * ss,struct symsrc * runtime_ss __maybe_unused,int kmodule __maybe_unused)319 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
320 struct symsrc *ss,
321 struct symsrc *runtime_ss __maybe_unused,
322 int kmodule __maybe_unused)
323 {
324 struct build_id bid = { .size = 0, };
325 int ret;
326
327 ret = fd__is_64_bit(ss->fd);
328 if (ret >= 0)
329 RC_CHK_ACCESS(dso)->is_64_bit = ret;
330
331 if (filename__read_build_id(ss->name, &bid) > 0)
332 dso__set_build_id(dso, &bid);
333 return 0;
334 }
335
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)336 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused,
337 mapfn_t mapfn __maybe_unused, void *data __maybe_unused,
338 bool *is_64_bit __maybe_unused)
339 {
340 return -1;
341 }
342
kcore_extract__create(struct kcore_extract * kce __maybe_unused)343 int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
344 {
345 return -1;
346 }
347
kcore_extract__delete(struct kcore_extract * kce __maybe_unused)348 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
349 {
350 }
351
kcore_copy(const char * from_dir __maybe_unused,const char * to_dir __maybe_unused)352 int kcore_copy(const char *from_dir __maybe_unused,
353 const char *to_dir __maybe_unused)
354 {
355 return -1;
356 }
357
symbol__elf_init(void)358 void symbol__elf_init(void)
359 {
360 }
361
filename__has_section(const char * filename __maybe_unused,const char * sec __maybe_unused)362 bool filename__has_section(const char *filename __maybe_unused, const char *sec __maybe_unused)
363 {
364 return false;
365 }
366