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	} 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	}
218out_free:
219	free(buf);
220out:
221	fclose(fp);
222	return ret;
223}
224
225int 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);
249out_free:
250	free(buf);
251out:
252	close(fd);
253	return ret;
254}
255
256int 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;
271out_close:
272	close(fd);
273out_errno:
274	dso->load_errno = errno;
275	return -1;
276}
277
278bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused)
279{
280	/* Assume all sym sources could be a runtime image. */
281	return true;
282}
283
284bool symsrc__has_symtab(struct symsrc *ss __maybe_unused)
285{
286	return false;
287}
288
289void symsrc__destroy(struct symsrc *ss)
290{
291	zfree(&ss->name);
292	close(ss->fd);
293}
294
295int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused,
296				struct symsrc *ss __maybe_unused)
297{
298	return 0;
299}
300
301static 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
318enum 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
339int 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
356int 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
363int kcore_extract__create(struct kcore_extract *kce __maybe_unused)
364{
365	return -1;
366}
367
368void kcore_extract__delete(struct kcore_extract *kce __maybe_unused)
369{
370}
371
372int kcore_copy(const char *from_dir __maybe_unused,
373	       const char *to_dir __maybe_unused)
374{
375	return -1;
376}
377
378void symbol__elf_init(void)
379{
380}
381
382char *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
389bool filename__has_section(const char *filename __maybe_unused, const char *sec __maybe_unused)
390{
391	return false;
392}