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
16static 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
34static 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
79int 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 */
89int 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		}
167	} else {
168		Elf64_Ehdr ehdr;
169		Elf64_Phdr *phdr;
170
171		if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1)
172			goto out;
173
174		if (need_swap) {
175			ehdr.e_phoff = bswap_64(ehdr.e_phoff);
176			ehdr.e_phentsize = bswap_16(ehdr.e_phentsize);
177			ehdr.e_phnum = bswap_16(ehdr.e_phnum);
178		}
179
180		buf_size = ehdr.e_phentsize * ehdr.e_phnum;
181		buf = malloc(buf_size);
182		if (buf == NULL)
183			goto out;
184
185		fseek(fp, ehdr.e_phoff, SEEK_SET);
186		if (fread(buf, buf_size, 1, fp) != 1)
187			goto out_free;
188
189		for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) {
190			void *tmp;
191			long offset;
192
193			if (need_swap) {
194				phdr->p_type = bswap_32(phdr->p_type);
195				phdr->p_offset = bswap_64(phdr->p_offset);
196				phdr->p_filesz = bswap_64(phdr->p_filesz);
197			}
198
199			if (phdr->p_type != PT_NOTE)
200				continue;
201
202			buf_size = phdr->p_filesz;
203			offset = phdr->p_offset;
204			tmp = realloc(buf, buf_size);
205			if (tmp == NULL)
206				goto out_free;
207
208			buf = tmp;
209			fseek(fp, offset, SEEK_SET);
210			if (fread(buf, buf_size, 1, fp) != 1)
211				goto out_free;
212
213			ret = read_build_id(buf, buf_size, bid, need_swap);
214			if (ret == 0) {
215				ret = bid->size;
216				break;
217			}
218		}
219	}
220out_free:
221	free(buf);
222out:
223	fclose(fp);
224	return ret;
225}
226
227int sysfs__read_build_id(const char *filename, struct build_id *bid)
228{
229	int fd;
230	int ret = -1;
231	struct stat stbuf;
232	size_t buf_size;
233	void *buf;
234
235	fd = open(filename, O_RDONLY);
236	if (fd < 0)
237		return -1;
238
239	if (fstat(fd, &stbuf) < 0)
240		goto out;
241
242	buf_size = stbuf.st_size;
243	buf = malloc(buf_size);
244	if (buf == NULL)
245		goto out;
246
247	if (read(fd, buf, buf_size) != (ssize_t) buf_size)
248		goto out_free;
249
250	ret = read_build_id(buf, buf_size, bid, false);
251out_free:
252	free(buf);
253out:
254	close(fd);
255	return ret;
256}
257
258int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
259	         enum dso_binary_type type)
260{
261	int fd = open(name, O_RDONLY);
262	if (fd < 0)
263		goto out_errno;
264
265	ss->name = strdup(name);
266	if (!ss->name)
267		goto out_close;
268
269	ss->fd = fd;
270	ss->type = type;
271
272	return 0;
273out_close:
274	close(fd);
275out_errno:
276	dso->load_errno = errno;
277	return -1;
278}
279
280bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
281{
282	/* Assume all sym sources could be a runtime image. */
283	return true;
284}
285
286bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
287{
288	return false;
289}
290
291void symsrc__destroy(struct symsrc *ss)
292{
293	zfree(&ss->name);
294	close(ss->fd);
295}
296
297int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
298				struct symsrc *ss __maybe_unused)
299{
300	return 0;
301}
302
303static int fd__is_64_bit(int fd)
304{
305	u8 e_ident[EI_NIDENT];
306
307	if (lseek(fd, 0, SEEK_SET))
308		return -1;
309
310	if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident))
311		return -1;
312
313	if (memcmp(e_ident, ELFMAG, SELFMAG) ||
314	    e_ident[EI_VERSION] != EV_CURRENT)
315		return -1;
316
317	return e_ident[EI_CLASS] == ELFCLASS64;
318}
319
320enum dso_type dso__type_fd(int fd)
321{
322	Elf64_Ehdr ehdr;
323	int ret;
324
325	ret = fd__is_64_bit(fd);
326	if (ret < 0)
327		return DSO__TYPE_UNKNOWN;
328
329	if (ret)
330		return DSO__TYPE_64BIT;
331
332	if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
333		return DSO__TYPE_UNKNOWN;
334
335	if (ehdr.e_machine == EM_X86_64)
336		return DSO__TYPE_X32BIT;
337
338	return DSO__TYPE_32BIT;
339}
340
341int dso__load_sym(struct dso *dso, struct map *map __maybe_unused,
342		  struct symsrc *ss,
343		  struct symsrc *runtime_ss __maybe_unused,
344		  int kmodule __maybe_unused)
345{
346	struct build_id bid;
347	int ret;
348
349	ret = fd__is_64_bit(ss->fd);
350	if (ret >= 0)
351		dso->is_64_bit = ret;
352
353	if (filename__read_build_id(ss->name, &bid) > 0)
354		dso__set_build_id(dso, &bid);
355	return 0;
356}
357
358int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused,
359		    mapfn_t mapfn __maybe_unused, void *data __maybe_unused,
360		    bool *is_64_bit __maybe_unused)
361{
362	return -1;
363}
364
365int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
366{
367	return -1;
368}
369
370void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
371{
372}
373
374int kcore_copy(const char *from_dir __maybe_unused,
375	       const char *to_dir __maybe_unused)
376{
377	return -1;
378}
379
380void symbol__elf_init(void)
381{
382}
383
384char *dso__demangle_sym(struct dso *dso __maybe_unused,
385			int kmodule __maybe_unused,
386			const char *elf_name __maybe_unused)
387{
388	return NULL;
389}
390
391bool filename__has_section(const char *filename __maybe_unused, const char *sec __maybe_unused)
392{
393	return false;
394}
395