xref: /openbmc/linux/tools/perf/util/symbol-minimal.c (revision b8d312aa)
1 // SPDX-License-Identifier: GPL-2.0
2 #include "symbol.h"
3 #include "util.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 
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 
33 static int read_build_id(void *note_data, size_t note_len, void *bf,
34 			 size_t size, bool need_swap)
35 {
36 	struct {
37 		u32 n_namesz;
38 		u32 n_descsz;
39 		u32 n_type;
40 	} *nhdr;
41 	void *ptr;
42 
43 	ptr = note_data;
44 	while (ptr < (note_data + note_len)) {
45 		const char *name;
46 		size_t namesz, descsz;
47 
48 		nhdr = ptr;
49 		if (need_swap) {
50 			nhdr->n_namesz = bswap_32(nhdr->n_namesz);
51 			nhdr->n_descsz = bswap_32(nhdr->n_descsz);
52 			nhdr->n_type = bswap_32(nhdr->n_type);
53 		}
54 
55 		namesz = NOTE_ALIGN(nhdr->n_namesz);
56 		descsz = NOTE_ALIGN(nhdr->n_descsz);
57 
58 		ptr += sizeof(*nhdr);
59 		name = ptr;
60 		ptr += namesz;
61 		if (nhdr->n_type == NT_GNU_BUILD_ID &&
62 		    nhdr->n_namesz == sizeof("GNU")) {
63 			if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
64 				size_t sz = min(size, descsz);
65 				memcpy(bf, ptr, sz);
66 				memset(bf + sz, 0, size - sz);
67 				return 0;
68 			}
69 		}
70 		ptr += descsz;
71 	}
72 
73 	return -1;
74 }
75 
76 int filename__read_debuglink(const char *filename __maybe_unused,
77 			     char *debuglink __maybe_unused,
78 			     size_t size __maybe_unused)
79 {
80 	return -1;
81 }
82 
83 /*
84  * Just try PT_NOTE header otherwise fails
85  */
86 int filename__read_build_id(const char *filename, void *bf, size_t size)
87 {
88 	FILE *fp;
89 	int ret = -1;
90 	bool need_swap = false;
91 	u8 e_ident[EI_NIDENT];
92 	size_t buf_size;
93 	void *buf;
94 	int i;
95 
96 	fp = fopen(filename, "r");
97 	if (fp == NULL)
98 		return -1;
99 
100 	if (fread(e_ident, sizeof(e_ident), 1, fp) != 1)
101 		goto out;
102 
103 	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
104 	    e_ident[EI_VERSION] != EV_CURRENT)
105 		goto out;
106 
107 	need_swap = check_need_swap(e_ident[EI_DATA]);
108 
109 	/* for simplicity */
110 	fseek(fp, 0, SEEK_SET);
111 
112 	if (e_ident[EI_CLASS] == ELFCLASS32) {
113 		Elf32_Ehdr ehdr;
114 		Elf32_Phdr *phdr;
115 
116 		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
117 			goto out;
118 
119 		if (need_swap) {
120 			ehdr.e_phoff = bswap_32(ehdr.e_phoff);
121 			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
122 			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
123 		}
124 
125 		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
126 		buf = malloc(buf_size);
127 		if (buf == NULL)
128 			goto out;
129 
130 		fseek(fp, ehdr.e_phoff, SEEK_SET);
131 		if (fread(buf, buf_size, 1, fp) != 1)
132 			goto out_free;
133 
134 		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
135 			void *tmp;
136 			long offset;
137 
138 			if (need_swap) {
139 				phdr->p_type = bswap_32(phdr->p_type);
140 				phdr->p_offset = bswap_32(phdr->p_offset);
141 				phdr->p_filesz = bswap_32(phdr->p_filesz);
142 			}
143 
144 			if (phdr->p_type != PT_NOTE)
145 				continue;
146 
147 			buf_size = phdr->p_filesz;
148 			offset = phdr->p_offset;
149 			tmp = realloc(buf, buf_size);
150 			if (tmp == NULL)
151 				goto out_free;
152 
153 			buf = tmp;
154 			fseek(fp, offset, SEEK_SET);
155 			if (fread(buf, buf_size, 1, fp) != 1)
156 				goto out_free;
157 
158 			ret = read_build_id(buf, buf_size, bf, size, need_swap);
159 			if (ret == 0)
160 				ret = size;
161 			break;
162 		}
163 	} else {
164 		Elf64_Ehdr ehdr;
165 		Elf64_Phdr *phdr;
166 
167 		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
168 			goto out;
169 
170 		if (need_swap) {
171 			ehdr.e_phoff = bswap_64(ehdr.e_phoff);
172 			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
173 			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
174 		}
175 
176 		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
177 		buf = malloc(buf_size);
178 		if (buf == NULL)
179 			goto out;
180 
181 		fseek(fp, ehdr.e_phoff, SEEK_SET);
182 		if (fread(buf, buf_size, 1, fp) != 1)
183 			goto out_free;
184 
185 		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
186 			void *tmp;
187 			long offset;
188 
189 			if (need_swap) {
190 				phdr->p_type = bswap_32(phdr->p_type);
191 				phdr->p_offset = bswap_64(phdr->p_offset);
192 				phdr->p_filesz = bswap_64(phdr->p_filesz);
193 			}
194 
195 			if (phdr->p_type != PT_NOTE)
196 				continue;
197 
198 			buf_size = phdr->p_filesz;
199 			offset = phdr->p_offset;
200 			tmp = realloc(buf, buf_size);
201 			if (tmp == NULL)
202 				goto out_free;
203 
204 			buf = tmp;
205 			fseek(fp, offset, SEEK_SET);
206 			if (fread(buf, buf_size, 1, fp) != 1)
207 				goto out_free;
208 
209 			ret = read_build_id(buf, buf_size, bf, size, need_swap);
210 			if (ret == 0)
211 				ret = size;
212 			break;
213 		}
214 	}
215 out_free:
216 	free(buf);
217 out:
218 	fclose(fp);
219 	return ret;
220 }
221 
222 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
223 {
224 	int fd;
225 	int ret = -1;
226 	struct stat stbuf;
227 	size_t buf_size;
228 	void *buf;
229 
230 	fd = open(filename, O_RDONLY);
231 	if (fd < 0)
232 		return -1;
233 
234 	if (fstat(fd, &stbuf) < 0)
235 		goto out;
236 
237 	buf_size = stbuf.st_size;
238 	buf = malloc(buf_size);
239 	if (buf == NULL)
240 		goto out;
241 
242 	if (read(fd, buf, buf_size) != (ssize_t) buf_size)
243 		goto out_free;
244 
245 	ret = read_build_id(buf, buf_size, build_id, size, false);
246 out_free:
247 	free(buf);
248 out:
249 	close(fd);
250 	return ret;
251 }
252 
253 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
254 	         enum dso_binary_type type)
255 {
256 	int fd = open(name, O_RDONLY);
257 	if (fd < 0)
258 		goto out_errno;
259 
260 	ss->name = strdup(name);
261 	if (!ss->name)
262 		goto out_close;
263 
264 	ss->fd = fd;
265 	ss->type = type;
266 
267 	return 0;
268 out_close:
269 	close(fd);
270 out_errno:
271 	dso->load_errno = errno;
272 	return -1;
273 }
274 
275 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
276 {
277 	/* Assume all sym sources could be a runtime image. */
278 	return true;
279 }
280 
281 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
282 {
283 	return false;
284 }
285 
286 void symsrc__destroy(struct symsrc *ss)
287 {
288 	zfree(&ss->name);
289 	close(ss->fd);
290 }
291 
292 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
293 				struct symsrc *ss __maybe_unused)
294 {
295 	return 0;
296 }
297 
298 static int fd__is_64_bit(int fd)
299 {
300 	u8 e_ident[EI_NIDENT];
301 
302 	if (lseek(fd, 0, SEEK_SET))
303 		return -1;
304 
305 	if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident))
306 		return -1;
307 
308 	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
309 	    e_ident[EI_VERSION] != EV_CURRENT)
310 		return -1;
311 
312 	return e_ident[EI_CLASS] == ELFCLASS64;
313 }
314 
315 enum dso_type dso__type_fd(int fd)
316 {
317 	Elf64_Ehdr ehdr;
318 	int ret;
319 
320 	ret = fd__is_64_bit(fd);
321 	if (ret < 0)
322 		return DSO__TYPE_UNKNOWN;
323 
324 	if (ret)
325 		return DSO__TYPE_64BIT;
326 
327 	if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
328 		return DSO__TYPE_UNKNOWN;
329 
330 	if (ehdr.e_machine == EM_X86_64)
331 		return DSO__TYPE_X32BIT;
332 
333 	return DSO__TYPE_32BIT;
334 }
335 
336 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
337 		  struct symsrc *ss,
338 		  struct symsrc *runtime_ss __maybe_unused,
339 		  int kmodule __maybe_unused)
340 {
341 	unsigned char build_id[BUILD_ID_SIZE];
342 	int ret;
343 
344 	ret = fd__is_64_bit(ss->fd);
345 	if (ret >= 0)
346 		dso->is_64_bit = ret;
347 
348 	if (filename__read_build_id(ss->name, build_id, BUILD_ID_SIZE) > 0) {
349 		dso__set_build_id(dso, build_id);
350 	}
351 	return 0;
352 }
353 
354 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused,
355 		    mapfn_t mapfn __maybe_unused, void *data __maybe_unused,
356 		    bool *is_64_bit __maybe_unused)
357 {
358 	return -1;
359 }
360 
361 int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
362 {
363 	return -1;
364 }
365 
366 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
367 {
368 }
369 
370 int kcore_copy(const char *from_dir __maybe_unused,
371 	       const char *to_dir __maybe_unused)
372 {
373 	return -1;
374 }
375 
376 void symbol__elf_init(void)
377 {
378 }
379 
380 char *dso__demangle_sym(struct dso *dso __maybe_unused,
381 			int kmodule __maybe_unused,
382 			const char *elf_name __maybe_unused)
383 {
384 	return NULL;
385 }
386