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