1 #include "dso.h"
2 #include "symbol.h"
3 #include "symsrc.h"
4 
5 #include <errno.h>
6 #include <unistd.h>
7 #include <stdio.h>
8 #include <fcntl.h>
9 #include <string.h>
10 #include <stdlib.h>
11 #include <byteswap.h>
12 #include <sys/stat.h>
13 #include <linux/zalloc.h>
14 #include <internal/lib.h>
15 
check_need_swap(int file_endian)16 static bool check_need_swap(int file_endian)
17 {
18 	const int data = 1;
19 	u8 *check = (u8 *)&data;
20 	int host_endian;
21 
22 	if (check[0] == 1)
23 		host_endian = ELFDATA2LSB;
24 	else
25 		host_endian = ELFDATA2MSB;
26 
27 	return host_endian != file_endian;
28 }
29 
30 #define NOTE_ALIGN(sz) (((sz) + 3) & ~3)
31 
32 #define NT_GNU_BUILD_ID	3
33 
read_build_id(void * note_data,size_t note_len,struct build_id * bid,bool need_swap)34 static int read_build_id(void *note_data, size_t note_len, struct build_id *bid,
35 			 bool need_swap)
36 {
37 	size_t size = sizeof(bid->data);
38 	struct {
39 		u32 n_namesz;
40 		u32 n_descsz;
41 		u32 n_type;
42 	} *nhdr;
43 	void *ptr;
44 
45 	ptr = note_data;
46 	while (ptr < (note_data + note_len)) {
47 		const char *name;
48 		size_t namesz, descsz;
49 
50 		nhdr = ptr;
51 		if (need_swap) {
52 			nhdr->n_namesz = bswap_32(nhdr->n_namesz);
53 			nhdr->n_descsz = bswap_32(nhdr->n_descsz);
54 			nhdr->n_type = bswap_32(nhdr->n_type);
55 		}
56 
57 		namesz = NOTE_ALIGN(nhdr->n_namesz);
58 		descsz = NOTE_ALIGN(nhdr->n_descsz);
59 
60 		ptr += sizeof(*nhdr);
61 		name = ptr;
62 		ptr += namesz;
63 		if (nhdr->n_type == NT_GNU_BUILD_ID &&
64 		    nhdr->n_namesz == sizeof("GNU")) {
65 			if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
66 				size_t sz = min(size, descsz);
67 				memcpy(bid->data, ptr, sz);
68 				memset(bid->data + sz, 0, size - sz);
69 				bid->size = sz;
70 				return 0;
71 			}
72 		}
73 		ptr += descsz;
74 	}
75 
76 	return -1;
77 }
78 
filename__read_debuglink(const char * filename __maybe_unused,char * debuglink __maybe_unused,size_t size __maybe_unused)79 int filename__read_debuglink(const char *filename __maybe_unused,
80 			     char *debuglink __maybe_unused,
81 			     size_t size __maybe_unused)
82 {
83 	return -1;
84 }
85 
86 /*
87  * Just try PT_NOTE header otherwise fails
88  */
filename__read_build_id(const char * filename,struct build_id * bid)89 int filename__read_build_id(const char *filename, struct build_id *bid)
90 {
91 	FILE *fp;
92 	int ret = -1;
93 	bool need_swap = false;
94 	u8 e_ident[EI_NIDENT];
95 	size_t buf_size;
96 	void *buf;
97 	int i;
98 
99 	fp = fopen(filename, "r");
100 	if (fp == NULL)
101 		return -1;
102 
103 	if (fread(e_ident, sizeof(e_ident), 1, fp) != 1)
104 		goto out;
105 
106 	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
107 	    e_ident[EI_VERSION] != EV_CURRENT)
108 		goto out;
109 
110 	need_swap = check_need_swap(e_ident[EI_DATA]);
111 
112 	/* for simplicity */
113 	fseek(fp, 0, SEEK_SET);
114 
115 	if (e_ident[EI_CLASS] == ELFCLASS32) {
116 		Elf32_Ehdr ehdr;
117 		Elf32_Phdr *phdr;
118 
119 		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
120 			goto out;
121 
122 		if (need_swap) {
123 			ehdr.e_phoff = bswap_32(ehdr.e_phoff);
124 			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
125 			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
126 		}
127 
128 		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
129 		buf = malloc(buf_size);
130 		if (buf == NULL)
131 			goto out;
132 
133 		fseek(fp, ehdr.e_phoff, SEEK_SET);
134 		if (fread(buf, buf_size, 1, fp) != 1)
135 			goto out_free;
136 
137 		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
138 			void *tmp;
139 			long offset;
140 
141 			if (need_swap) {
142 				phdr->p_type = bswap_32(phdr->p_type);
143 				phdr->p_offset = bswap_32(phdr->p_offset);
144 				phdr->p_filesz = bswap_32(phdr->p_filesz);
145 			}
146 
147 			if (phdr->p_type != PT_NOTE)
148 				continue;
149 
150 			buf_size = phdr->p_filesz;
151 			offset = phdr->p_offset;
152 			tmp = realloc(buf, buf_size);
153 			if (tmp == NULL)
154 				goto out_free;
155 
156 			buf = tmp;
157 			fseek(fp, offset, SEEK_SET);
158 			if (fread(buf, buf_size, 1, fp) != 1)
159 				goto out_free;
160 
161 			ret = read_build_id(buf, buf_size, bid, need_swap);
162 			if (ret == 0)
163 				ret = bid->size;
164 			break;
165 		}
166 	} else {
167 		Elf64_Ehdr ehdr;
168 		Elf64_Phdr *phdr;
169 
170 		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
171 			goto out;
172 
173 		if (need_swap) {
174 			ehdr.e_phoff = bswap_64(ehdr.e_phoff);
175 			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
176 			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
177 		}
178 
179 		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
180 		buf = malloc(buf_size);
181 		if (buf == NULL)
182 			goto out;
183 
184 		fseek(fp, ehdr.e_phoff, SEEK_SET);
185 		if (fread(buf, buf_size, 1, fp) != 1)
186 			goto out_free;
187 
188 		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
189 			void *tmp;
190 			long offset;
191 
192 			if (need_swap) {
193 				phdr->p_type = bswap_32(phdr->p_type);
194 				phdr->p_offset = bswap_64(phdr->p_offset);
195 				phdr->p_filesz = bswap_64(phdr->p_filesz);
196 			}
197 
198 			if (phdr->p_type != PT_NOTE)
199 				continue;
200 
201 			buf_size = phdr->p_filesz;
202 			offset = phdr->p_offset;
203 			tmp = realloc(buf, buf_size);
204 			if (tmp == NULL)
205 				goto out_free;
206 
207 			buf = tmp;
208 			fseek(fp, offset, SEEK_SET);
209 			if (fread(buf, buf_size, 1, fp) != 1)
210 				goto out_free;
211 
212 			ret = read_build_id(buf, buf_size, bid, need_swap);
213 			if (ret == 0)
214 				ret = bid->size;
215 			break;
216 		}
217 	}
218 out_free:
219 	free(buf);
220 out:
221 	fclose(fp);
222 	return ret;
223 }
224 
sysfs__read_build_id(const char * filename,struct build_id * bid)225 int sysfs__read_build_id(const char *filename, struct build_id *bid)
226 {
227 	int fd;
228 	int ret = -1;
229 	struct stat stbuf;
230 	size_t buf_size;
231 	void *buf;
232 
233 	fd = open(filename, O_RDONLY);
234 	if (fd < 0)
235 		return -1;
236 
237 	if (fstat(fd, &stbuf) < 0)
238 		goto out;
239 
240 	buf_size = stbuf.st_size;
241 	buf = malloc(buf_size);
242 	if (buf == NULL)
243 		goto out;
244 
245 	if (read(fd, buf, buf_size) != (ssize_t) buf_size)
246 		goto out_free;
247 
248 	ret = read_build_id(buf, buf_size, bid, false);
249 out_free:
250 	free(buf);
251 out:
252 	close(fd);
253 	return ret;
254 }
255 
symsrc__init(struct symsrc * ss,struct dso * dso,const char * name,enum dso_binary_type type)256 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
257 	         enum dso_binary_type type)
258 {
259 	int fd = open(name, O_RDONLY);
260 	if (fd < 0)
261 		goto out_errno;
262 
263 	ss->name = strdup(name);
264 	if (!ss->name)
265 		goto out_close;
266 
267 	ss->fd = fd;
268 	ss->type = type;
269 
270 	return 0;
271 out_close:
272 	close(fd);
273 out_errno:
274 	dso->load_errno = errno;
275 	return -1;
276 }
277 
symsrc__possibly_runtime(struct symsrc * ss __maybe_unused)278 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
279 {
280 	/* Assume all sym sources could be a runtime image. */
281 	return true;
282 }
283 
symsrc__has_symtab(struct symsrc * ss __maybe_unused)284 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
285 {
286 	return false;
287 }
288 
symsrc__destroy(struct symsrc * ss)289 void symsrc__destroy(struct symsrc *ss)
290 {
291 	zfree(&ss->name);
292 	close(ss->fd);
293 }
294 
dso__synthesize_plt_symbols(struct dso * dso __maybe_unused,struct symsrc * ss __maybe_unused)295 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
296 				struct symsrc *ss __maybe_unused)
297 {
298 	return 0;
299 }
300 
fd__is_64_bit(int fd)301 static int fd__is_64_bit(int fd)
302 {
303 	u8 e_ident[EI_NIDENT];
304 
305 	if (lseek(fd, 0, SEEK_SET))
306 		return -1;
307 
308 	if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident))
309 		return -1;
310 
311 	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
312 	    e_ident[EI_VERSION] != EV_CURRENT)
313 		return -1;
314 
315 	return e_ident[EI_CLASS] == ELFCLASS64;
316 }
317 
dso__type_fd(int fd)318 enum dso_type dso__type_fd(int fd)
319 {
320 	Elf64_Ehdr ehdr;
321 	int ret;
322 
323 	ret = fd__is_64_bit(fd);
324 	if (ret < 0)
325 		return DSO__TYPE_UNKNOWN;
326 
327 	if (ret)
328 		return DSO__TYPE_64BIT;
329 
330 	if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
331 		return DSO__TYPE_UNKNOWN;
332 
333 	if (ehdr.e_machine == EM_X86_64)
334 		return DSO__TYPE_X32BIT;
335 
336 	return DSO__TYPE_32BIT;
337 }
338 
dso__load_sym(struct dso * dso,struct map * map __maybe_unused,struct symsrc * ss,struct symsrc * runtime_ss __maybe_unused,int kmodule __maybe_unused)339 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
340 		  struct symsrc *ss,
341 		  struct symsrc *runtime_ss __maybe_unused,
342 		  int kmodule __maybe_unused)
343 {
344 	struct build_id bid;
345 	int ret;
346 
347 	ret = fd__is_64_bit(ss->fd);
348 	if (ret >= 0)
349 		dso->is_64_bit = ret;
350 
351 	if (filename__read_build_id(ss->name, &bid) > 0)
352 		dso__set_build_id(dso, &bid);
353 	return 0;
354 }
355 
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)356 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused,
357 		    mapfn_t mapfn __maybe_unused, void *data __maybe_unused,
358 		    bool *is_64_bit __maybe_unused)
359 {
360 	return -1;
361 }
362 
kcore_extract__create(struct kcore_extract * kce __maybe_unused)363 int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
364 {
365 	return -1;
366 }
367 
kcore_extract__delete(struct kcore_extract * kce __maybe_unused)368 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
369 {
370 }
371 
kcore_copy(const char * from_dir __maybe_unused,const char * to_dir __maybe_unused)372 int kcore_copy(const char *from_dir __maybe_unused,
373 	       const char *to_dir __maybe_unused)
374 {
375 	return -1;
376 }
377 
symbol__elf_init(void)378 void symbol__elf_init(void)
379 {
380 }
381 
dso__demangle_sym(struct dso * dso __maybe_unused,int kmodule __maybe_unused,const char * elf_name __maybe_unused)382 char *dso__demangle_sym(struct dso *dso __maybe_unused,
383 			int kmodule __maybe_unused,
384 			const char *elf_name __maybe_unused)
385 {
386 	return NULL;
387 }
388