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1 // SPDX-License-Identifier: GPL-2.0
2 #include "symbol.h"
3 #include "util.h"
4 
5 #include <errno.h>
6 #include <stdio.h>
7 #include <fcntl.h>
8 #include <string.h>
9 #include <byteswap.h>
10 #include <sys/stat.h>
11 
12 
check_need_swap(int file_endian)13 static bool check_need_swap(int file_endian)
14 {
15 	const int data = 1;
16 	u8 *check = (u8 *)&data;
17 	int host_endian;
18 
19 	if (check[0] == 1)
20 		host_endian = ELFDATA2LSB;
21 	else
22 		host_endian = ELFDATA2MSB;
23 
24 	return host_endian != file_endian;
25 }
26 
27 #define NOTE_ALIGN(sz) (((sz) + 3) & ~3)
28 
29 #define NT_GNU_BUILD_ID	3
30 
read_build_id(void * note_data,size_t note_len,void * bf,size_t size,bool need_swap)31 static int read_build_id(void *note_data, size_t note_len, void *bf,
32 			 size_t size, bool need_swap)
33 {
34 	struct {
35 		u32 n_namesz;
36 		u32 n_descsz;
37 		u32 n_type;
38 	} *nhdr;
39 	void *ptr;
40 
41 	ptr = note_data;
42 	while (ptr < (note_data + note_len)) {
43 		const char *name;
44 		size_t namesz, descsz;
45 
46 		nhdr = ptr;
47 		if (need_swap) {
48 			nhdr->n_namesz = bswap_32(nhdr->n_namesz);
49 			nhdr->n_descsz = bswap_32(nhdr->n_descsz);
50 			nhdr->n_type = bswap_32(nhdr->n_type);
51 		}
52 
53 		namesz = NOTE_ALIGN(nhdr->n_namesz);
54 		descsz = NOTE_ALIGN(nhdr->n_descsz);
55 
56 		ptr += sizeof(*nhdr);
57 		name = ptr;
58 		ptr += namesz;
59 		if (nhdr->n_type == NT_GNU_BUILD_ID &&
60 		    nhdr->n_namesz == sizeof("GNU")) {
61 			if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
62 				size_t sz = min(size, descsz);
63 				memcpy(bf, ptr, sz);
64 				memset(bf + sz, 0, size - sz);
65 				return 0;
66 			}
67 		}
68 		ptr += descsz;
69 	}
70 
71 	return -1;
72 }
73 
filename__read_debuglink(const char * filename __maybe_unused,char * debuglink __maybe_unused,size_t size __maybe_unused)74 int filename__read_debuglink(const char *filename __maybe_unused,
75 			     char *debuglink __maybe_unused,
76 			     size_t size __maybe_unused)
77 {
78 	return -1;
79 }
80 
81 /*
82  * Just try PT_NOTE header otherwise fails
83  */
filename__read_build_id(const char * filename,void * bf,size_t size)84 int filename__read_build_id(const char *filename, void *bf, size_t size)
85 {
86 	FILE *fp;
87 	int ret = -1;
88 	bool need_swap = false;
89 	u8 e_ident[EI_NIDENT];
90 	size_t buf_size;
91 	void *buf;
92 	int i;
93 
94 	fp = fopen(filename, "r");
95 	if (fp == NULL)
96 		return -1;
97 
98 	if (fread(e_ident, sizeof(e_ident), 1, fp) != 1)
99 		goto out;
100 
101 	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
102 	    e_ident[EI_VERSION] != EV_CURRENT)
103 		goto out;
104 
105 	need_swap = check_need_swap(e_ident[EI_DATA]);
106 
107 	/* for simplicity */
108 	fseek(fp, 0, SEEK_SET);
109 
110 	if (e_ident[EI_CLASS] == ELFCLASS32) {
111 		Elf32_Ehdr ehdr;
112 		Elf32_Phdr *phdr;
113 
114 		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
115 			goto out;
116 
117 		if (need_swap) {
118 			ehdr.e_phoff = bswap_32(ehdr.e_phoff);
119 			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
120 			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
121 		}
122 
123 		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
124 		buf = malloc(buf_size);
125 		if (buf == NULL)
126 			goto out;
127 
128 		fseek(fp, ehdr.e_phoff, SEEK_SET);
129 		if (fread(buf, buf_size, 1, fp) != 1)
130 			goto out_free;
131 
132 		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
133 			void *tmp;
134 			long offset;
135 
136 			if (need_swap) {
137 				phdr->p_type = bswap_32(phdr->p_type);
138 				phdr->p_offset = bswap_32(phdr->p_offset);
139 				phdr->p_filesz = bswap_32(phdr->p_filesz);
140 			}
141 
142 			if (phdr->p_type != PT_NOTE)
143 				continue;
144 
145 			buf_size = phdr->p_filesz;
146 			offset = phdr->p_offset;
147 			tmp = realloc(buf, buf_size);
148 			if (tmp == NULL)
149 				goto out_free;
150 
151 			buf = tmp;
152 			fseek(fp, offset, SEEK_SET);
153 			if (fread(buf, buf_size, 1, fp) != 1)
154 				goto out_free;
155 
156 			ret = read_build_id(buf, buf_size, bf, size, need_swap);
157 			if (ret == 0)
158 				ret = size;
159 			break;
160 		}
161 	} else {
162 		Elf64_Ehdr ehdr;
163 		Elf64_Phdr *phdr;
164 
165 		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
166 			goto out;
167 
168 		if (need_swap) {
169 			ehdr.e_phoff = bswap_64(ehdr.e_phoff);
170 			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
171 			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
172 		}
173 
174 		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
175 		buf = malloc(buf_size);
176 		if (buf == NULL)
177 			goto out;
178 
179 		fseek(fp, ehdr.e_phoff, SEEK_SET);
180 		if (fread(buf, buf_size, 1, fp) != 1)
181 			goto out_free;
182 
183 		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
184 			void *tmp;
185 			long offset;
186 
187 			if (need_swap) {
188 				phdr->p_type = bswap_32(phdr->p_type);
189 				phdr->p_offset = bswap_64(phdr->p_offset);
190 				phdr->p_filesz = bswap_64(phdr->p_filesz);
191 			}
192 
193 			if (phdr->p_type != PT_NOTE)
194 				continue;
195 
196 			buf_size = phdr->p_filesz;
197 			offset = phdr->p_offset;
198 			tmp = realloc(buf, buf_size);
199 			if (tmp == NULL)
200 				goto out_free;
201 
202 			buf = tmp;
203 			fseek(fp, offset, SEEK_SET);
204 			if (fread(buf, buf_size, 1, fp) != 1)
205 				goto out_free;
206 
207 			ret = read_build_id(buf, buf_size, bf, size, need_swap);
208 			if (ret == 0)
209 				ret = size;
210 			break;
211 		}
212 	}
213 out_free:
214 	free(buf);
215 out:
216 	fclose(fp);
217 	return ret;
218 }
219 
sysfs__read_build_id(const char * filename,void * build_id,size_t size)220 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
221 {
222 	int fd;
223 	int ret = -1;
224 	struct stat stbuf;
225 	size_t buf_size;
226 	void *buf;
227 
228 	fd = open(filename, O_RDONLY);
229 	if (fd < 0)
230 		return -1;
231 
232 	if (fstat(fd, &stbuf) < 0)
233 		goto out;
234 
235 	buf_size = stbuf.st_size;
236 	buf = malloc(buf_size);
237 	if (buf == NULL)
238 		goto out;
239 
240 	if (read(fd, buf, buf_size) != (ssize_t) buf_size)
241 		goto out_free;
242 
243 	ret = read_build_id(buf, buf_size, build_id, size, false);
244 out_free:
245 	free(buf);
246 out:
247 	close(fd);
248 	return ret;
249 }
250 
symsrc__init(struct symsrc * ss,struct dso * dso,const char * name,enum dso_binary_type type)251 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
252 	         enum dso_binary_type type)
253 {
254 	int fd = open(name, O_RDONLY);
255 	if (fd < 0)
256 		goto out_errno;
257 
258 	ss->name = strdup(name);
259 	if (!ss->name)
260 		goto out_close;
261 
262 	ss->fd = fd;
263 	ss->type = type;
264 
265 	return 0;
266 out_close:
267 	close(fd);
268 out_errno:
269 	dso->load_errno = errno;
270 	return -1;
271 }
272 
symsrc__possibly_runtime(struct symsrc * ss __maybe_unused)273 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
274 {
275 	/* Assume all sym sources could be a runtime image. */
276 	return true;
277 }
278 
symsrc__has_symtab(struct symsrc * ss __maybe_unused)279 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
280 {
281 	return false;
282 }
283 
symsrc__destroy(struct symsrc * ss)284 void symsrc__destroy(struct symsrc *ss)
285 {
286 	zfree(&ss->name);
287 	close(ss->fd);
288 }
289 
dso__synthesize_plt_symbols(struct dso * dso __maybe_unused,struct symsrc * ss __maybe_unused,struct map * map __maybe_unused)290 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
291 				struct symsrc *ss __maybe_unused,
292 				struct map *map __maybe_unused)
293 {
294 	return 0;
295 }
296 
fd__is_64_bit(int fd)297 static int fd__is_64_bit(int fd)
298 {
299 	u8 e_ident[EI_NIDENT];
300 
301 	if (lseek(fd, 0, SEEK_SET))
302 		return -1;
303 
304 	if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident))
305 		return -1;
306 
307 	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
308 	    e_ident[EI_VERSION] != EV_CURRENT)
309 		return -1;
310 
311 	return e_ident[EI_CLASS] == ELFCLASS64;
312 }
313 
dso__type_fd(int fd)314 enum dso_type dso__type_fd(int fd)
315 {
316 	Elf64_Ehdr ehdr;
317 	int ret;
318 
319 	ret = fd__is_64_bit(fd);
320 	if (ret < 0)
321 		return DSO__TYPE_UNKNOWN;
322 
323 	if (ret)
324 		return DSO__TYPE_64BIT;
325 
326 	if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
327 		return DSO__TYPE_UNKNOWN;
328 
329 	if (ehdr.e_machine == EM_X86_64)
330 		return DSO__TYPE_X32BIT;
331 
332 	return DSO__TYPE_32BIT;
333 }
334 
dso__load_sym(struct dso * dso,struct map * map __maybe_unused,struct symsrc * ss,struct symsrc * runtime_ss __maybe_unused,int kmodule __maybe_unused)335 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
336 		  struct symsrc *ss,
337 		  struct symsrc *runtime_ss __maybe_unused,
338 		  int kmodule __maybe_unused)
339 {
340 	unsigned char build_id[BUILD_ID_SIZE];
341 	int ret;
342 
343 	ret = fd__is_64_bit(ss->fd);
344 	if (ret >= 0)
345 		dso->is_64_bit = ret;
346 
347 	if (filename__read_build_id(ss->name, build_id, BUILD_ID_SIZE) > 0) {
348 		dso__set_build_id(dso, build_id);
349 	}
350 	return 0;
351 }
352 
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)353 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused,
354 		    mapfn_t mapfn __maybe_unused, void *data __maybe_unused,
355 		    bool *is_64_bit __maybe_unused)
356 {
357 	return -1;
358 }
359 
kcore_extract__create(struct kcore_extract * kce __maybe_unused)360 int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
361 {
362 	return -1;
363 }
364 
kcore_extract__delete(struct kcore_extract * kce __maybe_unused)365 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
366 {
367 }
368 
kcore_copy(const char * from_dir __maybe_unused,const char * to_dir __maybe_unused)369 int kcore_copy(const char *from_dir __maybe_unused,
370 	       const char *to_dir __maybe_unused)
371 {
372 	return -1;
373 }
374 
symbol__elf_init(void)375 void symbol__elf_init(void)
376 {
377 }
378 
dso__demangle_sym(struct dso * dso __maybe_unused,int kmodule __maybe_unused,const char * elf_name __maybe_unused)379 char *dso__demangle_sym(struct dso *dso __maybe_unused,
380 			int kmodule __maybe_unused,
381 			const char *elf_name __maybe_unused)
382 {
383 	return NULL;
384 }
385