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