xref: /linux/tools/perf/util/dso.c (revision 1c695c88a1092b4013e3fffbe0ca685149165403)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <asm/bug.h>
3 #include <linux/kernel.h>
4 #include <linux/string.h>
5 #include <linux/zalloc.h>
6 #include <sys/time.h>
7 #include <sys/resource.h>
8 #include <sys/types.h>
9 #include <sys/stat.h>
10 #include <unistd.h>
11 #include <errno.h>
12 #include <fcntl.h>
13 #include <stdlib.h>
14 #include <bpf/libbpf.h>
15 #include "bpf-event.h"
16 #include "compress.h"
17 #include "env.h"
18 #include "namespaces.h"
19 #include "path.h"
20 #include "map.h"
21 #include "symbol.h"
22 #include "srcline.h"
23 #include "dso.h"
24 #include "dsos.h"
25 #include "machine.h"
26 #include "auxtrace.h"
27 #include "util.h" /* O_CLOEXEC for older systems */
28 #include "debug.h"
29 #include "string2.h"
30 #include "vdso.h"
31 
32 static const char * const debuglink_paths[] = {
33 	"%.0s%s",
34 	"%s/%s",
35 	"%s/.debug/%s",
36 	"/usr/lib/debug%s/%s"
37 };
38 
39 char dso__symtab_origin(const struct dso *dso)
40 {
41 	static const char origin[] = {
42 		[DSO_BINARY_TYPE__KALLSYMS]			= 'k',
43 		[DSO_BINARY_TYPE__VMLINUX]			= 'v',
44 		[DSO_BINARY_TYPE__JAVA_JIT]			= 'j',
45 		[DSO_BINARY_TYPE__DEBUGLINK]			= 'l',
46 		[DSO_BINARY_TYPE__BUILD_ID_CACHE]		= 'B',
47 		[DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO]	= 'D',
48 		[DSO_BINARY_TYPE__FEDORA_DEBUGINFO]		= 'f',
49 		[DSO_BINARY_TYPE__UBUNTU_DEBUGINFO]		= 'u',
50 		[DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO]	= 'x',
51 		[DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO]	= 'o',
52 		[DSO_BINARY_TYPE__BUILDID_DEBUGINFO]		= 'b',
53 		[DSO_BINARY_TYPE__SYSTEM_PATH_DSO]		= 'd',
54 		[DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE]		= 'K',
55 		[DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP]	= 'm',
56 		[DSO_BINARY_TYPE__GUEST_KALLSYMS]		= 'g',
57 		[DSO_BINARY_TYPE__GUEST_KMODULE]		= 'G',
58 		[DSO_BINARY_TYPE__GUEST_KMODULE_COMP]		= 'M',
59 		[DSO_BINARY_TYPE__GUEST_VMLINUX]		= 'V',
60 	};
61 
62 	if (dso == NULL || dso->symtab_type == DSO_BINARY_TYPE__NOT_FOUND)
63 		return '!';
64 	return origin[dso->symtab_type];
65 }
66 
67 int dso__read_binary_type_filename(const struct dso *dso,
68 				   enum dso_binary_type type,
69 				   char *root_dir, char *filename, size_t size)
70 {
71 	char build_id_hex[SBUILD_ID_SIZE];
72 	int ret = 0;
73 	size_t len;
74 
75 	switch (type) {
76 	case DSO_BINARY_TYPE__DEBUGLINK:
77 	{
78 		const char *last_slash;
79 		char dso_dir[PATH_MAX];
80 		char symfile[PATH_MAX];
81 		unsigned int i;
82 
83 		len = __symbol__join_symfs(filename, size, dso->long_name);
84 		last_slash = filename + len;
85 		while (last_slash != filename && *last_slash != '/')
86 			last_slash--;
87 
88 		strncpy(dso_dir, filename, last_slash - filename);
89 		dso_dir[last_slash-filename] = '\0';
90 
91 		if (!is_regular_file(filename)) {
92 			ret = -1;
93 			break;
94 		}
95 
96 		ret = filename__read_debuglink(filename, symfile, PATH_MAX);
97 		if (ret)
98 			break;
99 
100 		/* Check predefined locations where debug file might reside */
101 		ret = -1;
102 		for (i = 0; i < ARRAY_SIZE(debuglink_paths); i++) {
103 			snprintf(filename, size,
104 					debuglink_paths[i], dso_dir, symfile);
105 			if (is_regular_file(filename)) {
106 				ret = 0;
107 				break;
108 			}
109 		}
110 
111 		break;
112 	}
113 	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
114 		if (dso__build_id_filename(dso, filename, size, false) == NULL)
115 			ret = -1;
116 		break;
117 
118 	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
119 		if (dso__build_id_filename(dso, filename, size, true) == NULL)
120 			ret = -1;
121 		break;
122 
123 	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
124 		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
125 		snprintf(filename + len, size - len, "%s.debug", dso->long_name);
126 		break;
127 
128 	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
129 		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
130 		snprintf(filename + len, size - len, "%s", dso->long_name);
131 		break;
132 
133 	case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
134 		/*
135 		 * Ubuntu can mixup /usr/lib with /lib, putting debuginfo in
136 		 * /usr/lib/debug/lib when it is expected to be in
137 		 * /usr/lib/debug/usr/lib
138 		 */
139 		if (strlen(dso->long_name) < 9 ||
140 		    strncmp(dso->long_name, "/usr/lib/", 9)) {
141 			ret = -1;
142 			break;
143 		}
144 		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
145 		snprintf(filename + len, size - len, "%s", dso->long_name + 4);
146 		break;
147 
148 	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
149 	{
150 		const char *last_slash;
151 		size_t dir_size;
152 
153 		last_slash = dso->long_name + dso->long_name_len;
154 		while (last_slash != dso->long_name && *last_slash != '/')
155 			last_slash--;
156 
157 		len = __symbol__join_symfs(filename, size, "");
158 		dir_size = last_slash - dso->long_name + 2;
159 		if (dir_size > (size - len)) {
160 			ret = -1;
161 			break;
162 		}
163 		len += scnprintf(filename + len, dir_size, "%s",  dso->long_name);
164 		len += scnprintf(filename + len , size - len, ".debug%s",
165 								last_slash);
166 		break;
167 	}
168 
169 	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
170 		if (!dso->has_build_id) {
171 			ret = -1;
172 			break;
173 		}
174 
175 		build_id__sprintf(dso->build_id,
176 				  sizeof(dso->build_id),
177 				  build_id_hex);
178 		len = __symbol__join_symfs(filename, size, "/usr/lib/debug/.build-id/");
179 		snprintf(filename + len, size - len, "%.2s/%s.debug",
180 			 build_id_hex, build_id_hex + 2);
181 		break;
182 
183 	case DSO_BINARY_TYPE__VMLINUX:
184 	case DSO_BINARY_TYPE__GUEST_VMLINUX:
185 	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
186 		__symbol__join_symfs(filename, size, dso->long_name);
187 		break;
188 
189 	case DSO_BINARY_TYPE__GUEST_KMODULE:
190 	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
191 		path__join3(filename, size, symbol_conf.symfs,
192 			    root_dir, dso->long_name);
193 		break;
194 
195 	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
196 	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
197 		__symbol__join_symfs(filename, size, dso->long_name);
198 		break;
199 
200 	case DSO_BINARY_TYPE__KCORE:
201 	case DSO_BINARY_TYPE__GUEST_KCORE:
202 		snprintf(filename, size, "%s", dso->long_name);
203 		break;
204 
205 	default:
206 	case DSO_BINARY_TYPE__KALLSYMS:
207 	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
208 	case DSO_BINARY_TYPE__JAVA_JIT:
209 	case DSO_BINARY_TYPE__BPF_PROG_INFO:
210 	case DSO_BINARY_TYPE__BPF_IMAGE:
211 	case DSO_BINARY_TYPE__OOL:
212 	case DSO_BINARY_TYPE__NOT_FOUND:
213 		ret = -1;
214 		break;
215 	}
216 
217 	return ret;
218 }
219 
220 enum {
221 	COMP_ID__NONE = 0,
222 };
223 
224 static const struct {
225 	const char *fmt;
226 	int (*decompress)(const char *input, int output);
227 	bool (*is_compressed)(const char *input);
228 } compressions[] = {
229 	[COMP_ID__NONE] = { .fmt = NULL, },
230 #ifdef HAVE_ZLIB_SUPPORT
231 	{ "gz", gzip_decompress_to_file, gzip_is_compressed },
232 #endif
233 #ifdef HAVE_LZMA_SUPPORT
234 	{ "xz", lzma_decompress_to_file, lzma_is_compressed },
235 #endif
236 	{ NULL, NULL, NULL },
237 };
238 
239 static int is_supported_compression(const char *ext)
240 {
241 	unsigned i;
242 
243 	for (i = 1; compressions[i].fmt; i++) {
244 		if (!strcmp(ext, compressions[i].fmt))
245 			return i;
246 	}
247 	return COMP_ID__NONE;
248 }
249 
250 bool is_kernel_module(const char *pathname, int cpumode)
251 {
252 	struct kmod_path m;
253 	int mode = cpumode & PERF_RECORD_MISC_CPUMODE_MASK;
254 
255 	WARN_ONCE(mode != cpumode,
256 		  "Internal error: passing unmasked cpumode (%x) to is_kernel_module",
257 		  cpumode);
258 
259 	switch (mode) {
260 	case PERF_RECORD_MISC_USER:
261 	case PERF_RECORD_MISC_HYPERVISOR:
262 	case PERF_RECORD_MISC_GUEST_USER:
263 		return false;
264 	/* Treat PERF_RECORD_MISC_CPUMODE_UNKNOWN as kernel */
265 	default:
266 		if (kmod_path__parse(&m, pathname)) {
267 			pr_err("Failed to check whether %s is a kernel module or not. Assume it is.",
268 					pathname);
269 			return true;
270 		}
271 	}
272 
273 	return m.kmod;
274 }
275 
276 bool dso__needs_decompress(struct dso *dso)
277 {
278 	return dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP ||
279 		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;
280 }
281 
282 static int decompress_kmodule(struct dso *dso, const char *name,
283 			      char *pathname, size_t len)
284 {
285 	char tmpbuf[] = KMOD_DECOMP_NAME;
286 	int fd = -1;
287 
288 	if (!dso__needs_decompress(dso))
289 		return -1;
290 
291 	if (dso->comp == COMP_ID__NONE)
292 		return -1;
293 
294 	/*
295 	 * We have proper compression id for DSO and yet the file
296 	 * behind the 'name' can still be plain uncompressed object.
297 	 *
298 	 * The reason is behind the logic we open the DSO object files,
299 	 * when we try all possible 'debug' objects until we find the
300 	 * data. So even if the DSO is represented by 'krava.xz' module,
301 	 * we can end up here opening ~/.debug/....23432432/debug' file
302 	 * which is not compressed.
303 	 *
304 	 * To keep this transparent, we detect this and return the file
305 	 * descriptor to the uncompressed file.
306 	 */
307 	if (!compressions[dso->comp].is_compressed(name))
308 		return open(name, O_RDONLY);
309 
310 	fd = mkstemp(tmpbuf);
311 	if (fd < 0) {
312 		dso->load_errno = errno;
313 		return -1;
314 	}
315 
316 	if (compressions[dso->comp].decompress(name, fd)) {
317 		dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
318 		close(fd);
319 		fd = -1;
320 	}
321 
322 	if (!pathname || (fd < 0))
323 		unlink(tmpbuf);
324 
325 	if (pathname && (fd >= 0))
326 		strlcpy(pathname, tmpbuf, len);
327 
328 	return fd;
329 }
330 
331 int dso__decompress_kmodule_fd(struct dso *dso, const char *name)
332 {
333 	return decompress_kmodule(dso, name, NULL, 0);
334 }
335 
336 int dso__decompress_kmodule_path(struct dso *dso, const char *name,
337 				 char *pathname, size_t len)
338 {
339 	int fd = decompress_kmodule(dso, name, pathname, len);
340 
341 	close(fd);
342 	return fd >= 0 ? 0 : -1;
343 }
344 
345 /*
346  * Parses kernel module specified in @path and updates
347  * @m argument like:
348  *
349  *    @comp - true if @path contains supported compression suffix,
350  *            false otherwise
351  *    @kmod - true if @path contains '.ko' suffix in right position,
352  *            false otherwise
353  *    @name - if (@alloc_name && @kmod) is true, it contains strdup-ed base name
354  *            of the kernel module without suffixes, otherwise strudup-ed
355  *            base name of @path
356  *    @ext  - if (@alloc_ext && @comp) is true, it contains strdup-ed string
357  *            the compression suffix
358  *
359  * Returns 0 if there's no strdup error, -ENOMEM otherwise.
360  */
361 int __kmod_path__parse(struct kmod_path *m, const char *path,
362 		       bool alloc_name)
363 {
364 	const char *name = strrchr(path, '/');
365 	const char *ext  = strrchr(path, '.');
366 	bool is_simple_name = false;
367 
368 	memset(m, 0x0, sizeof(*m));
369 	name = name ? name + 1 : path;
370 
371 	/*
372 	 * '.' is also a valid character for module name. For example:
373 	 * [aaa.bbb] is a valid module name. '[' should have higher
374 	 * priority than '.ko' suffix.
375 	 *
376 	 * The kernel names are from machine__mmap_name. Such
377 	 * name should belong to kernel itself, not kernel module.
378 	 */
379 	if (name[0] == '[') {
380 		is_simple_name = true;
381 		if ((strncmp(name, "[kernel.kallsyms]", 17) == 0) ||
382 		    (strncmp(name, "[guest.kernel.kallsyms", 22) == 0) ||
383 		    (strncmp(name, "[vdso]", 6) == 0) ||
384 		    (strncmp(name, "[vdso32]", 8) == 0) ||
385 		    (strncmp(name, "[vdsox32]", 9) == 0) ||
386 		    (strncmp(name, "[vsyscall]", 10) == 0)) {
387 			m->kmod = false;
388 
389 		} else
390 			m->kmod = true;
391 	}
392 
393 	/* No extension, just return name. */
394 	if ((ext == NULL) || is_simple_name) {
395 		if (alloc_name) {
396 			m->name = strdup(name);
397 			return m->name ? 0 : -ENOMEM;
398 		}
399 		return 0;
400 	}
401 
402 	m->comp = is_supported_compression(ext + 1);
403 	if (m->comp > COMP_ID__NONE)
404 		ext -= 3;
405 
406 	/* Check .ko extension only if there's enough name left. */
407 	if (ext > name)
408 		m->kmod = !strncmp(ext, ".ko", 3);
409 
410 	if (alloc_name) {
411 		if (m->kmod) {
412 			if (asprintf(&m->name, "[%.*s]", (int) (ext - name), name) == -1)
413 				return -ENOMEM;
414 		} else {
415 			if (asprintf(&m->name, "%s", name) == -1)
416 				return -ENOMEM;
417 		}
418 
419 		strreplace(m->name, '-', '_');
420 	}
421 
422 	return 0;
423 }
424 
425 void dso__set_module_info(struct dso *dso, struct kmod_path *m,
426 			  struct machine *machine)
427 {
428 	if (machine__is_host(machine))
429 		dso->symtab_type = DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE;
430 	else
431 		dso->symtab_type = DSO_BINARY_TYPE__GUEST_KMODULE;
432 
433 	/* _KMODULE_COMP should be next to _KMODULE */
434 	if (m->kmod && m->comp) {
435 		dso->symtab_type++;
436 		dso->comp = m->comp;
437 	}
438 
439 	dso__set_short_name(dso, strdup(m->name), true);
440 }
441 
442 /*
443  * Global list of open DSOs and the counter.
444  */
445 static LIST_HEAD(dso__data_open);
446 static long dso__data_open_cnt;
447 static pthread_mutex_t dso__data_open_lock = PTHREAD_MUTEX_INITIALIZER;
448 
449 static void dso__list_add(struct dso *dso)
450 {
451 	list_add_tail(&dso->data.open_entry, &dso__data_open);
452 	dso__data_open_cnt++;
453 }
454 
455 static void dso__list_del(struct dso *dso)
456 {
457 	list_del_init(&dso->data.open_entry);
458 	WARN_ONCE(dso__data_open_cnt <= 0,
459 		  "DSO data fd counter out of bounds.");
460 	dso__data_open_cnt--;
461 }
462 
463 static void close_first_dso(void);
464 
465 static int do_open(char *name)
466 {
467 	int fd;
468 	char sbuf[STRERR_BUFSIZE];
469 
470 	do {
471 		fd = open(name, O_RDONLY|O_CLOEXEC);
472 		if (fd >= 0)
473 			return fd;
474 
475 		pr_debug("dso open failed: %s\n",
476 			 str_error_r(errno, sbuf, sizeof(sbuf)));
477 		if (!dso__data_open_cnt || errno != EMFILE)
478 			break;
479 
480 		close_first_dso();
481 	} while (1);
482 
483 	return -1;
484 }
485 
486 static int __open_dso(struct dso *dso, struct machine *machine)
487 {
488 	int fd = -EINVAL;
489 	char *root_dir = (char *)"";
490 	char *name = malloc(PATH_MAX);
491 	bool decomp = false;
492 
493 	if (!name)
494 		return -ENOMEM;
495 
496 	if (machine)
497 		root_dir = machine->root_dir;
498 
499 	if (dso__read_binary_type_filename(dso, dso->binary_type,
500 					    root_dir, name, PATH_MAX))
501 		goto out;
502 
503 	if (!is_regular_file(name))
504 		goto out;
505 
506 	if (dso__needs_decompress(dso)) {
507 		char newpath[KMOD_DECOMP_LEN];
508 		size_t len = sizeof(newpath);
509 
510 		if (dso__decompress_kmodule_path(dso, name, newpath, len) < 0) {
511 			fd = -dso->load_errno;
512 			goto out;
513 		}
514 
515 		decomp = true;
516 		strcpy(name, newpath);
517 	}
518 
519 	fd = do_open(name);
520 
521 	if (decomp)
522 		unlink(name);
523 
524 out:
525 	free(name);
526 	return fd;
527 }
528 
529 static void check_data_close(void);
530 
531 /**
532  * dso_close - Open DSO data file
533  * @dso: dso object
534  *
535  * Open @dso's data file descriptor and updates
536  * list/count of open DSO objects.
537  */
538 static int open_dso(struct dso *dso, struct machine *machine)
539 {
540 	int fd;
541 	struct nscookie nsc;
542 
543 	if (dso->binary_type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
544 		nsinfo__mountns_enter(dso->nsinfo, &nsc);
545 	fd = __open_dso(dso, machine);
546 	if (dso->binary_type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
547 		nsinfo__mountns_exit(&nsc);
548 
549 	if (fd >= 0) {
550 		dso__list_add(dso);
551 		/*
552 		 * Check if we crossed the allowed number
553 		 * of opened DSOs and close one if needed.
554 		 */
555 		check_data_close();
556 	}
557 
558 	return fd;
559 }
560 
561 static void close_data_fd(struct dso *dso)
562 {
563 	if (dso->data.fd >= 0) {
564 		close(dso->data.fd);
565 		dso->data.fd = -1;
566 		dso->data.file_size = 0;
567 		dso__list_del(dso);
568 	}
569 }
570 
571 /**
572  * dso_close - Close DSO data file
573  * @dso: dso object
574  *
575  * Close @dso's data file descriptor and updates
576  * list/count of open DSO objects.
577  */
578 static void close_dso(struct dso *dso)
579 {
580 	close_data_fd(dso);
581 }
582 
583 static void close_first_dso(void)
584 {
585 	struct dso *dso;
586 
587 	dso = list_first_entry(&dso__data_open, struct dso, data.open_entry);
588 	close_dso(dso);
589 }
590 
591 static rlim_t get_fd_limit(void)
592 {
593 	struct rlimit l;
594 	rlim_t limit = 0;
595 
596 	/* Allow half of the current open fd limit. */
597 	if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
598 		if (l.rlim_cur == RLIM_INFINITY)
599 			limit = l.rlim_cur;
600 		else
601 			limit = l.rlim_cur / 2;
602 	} else {
603 		pr_err("failed to get fd limit\n");
604 		limit = 1;
605 	}
606 
607 	return limit;
608 }
609 
610 static rlim_t fd_limit;
611 
612 /*
613  * Used only by tests/dso-data.c to reset the environment
614  * for tests. I dont expect we should change this during
615  * standard runtime.
616  */
617 void reset_fd_limit(void)
618 {
619 	fd_limit = 0;
620 }
621 
622 static bool may_cache_fd(void)
623 {
624 	if (!fd_limit)
625 		fd_limit = get_fd_limit();
626 
627 	if (fd_limit == RLIM_INFINITY)
628 		return true;
629 
630 	return fd_limit > (rlim_t) dso__data_open_cnt;
631 }
632 
633 /*
634  * Check and close LRU dso if we crossed allowed limit
635  * for opened dso file descriptors. The limit is half
636  * of the RLIMIT_NOFILE files opened.
637 */
638 static void check_data_close(void)
639 {
640 	bool cache_fd = may_cache_fd();
641 
642 	if (!cache_fd)
643 		close_first_dso();
644 }
645 
646 /**
647  * dso__data_close - Close DSO data file
648  * @dso: dso object
649  *
650  * External interface to close @dso's data file descriptor.
651  */
652 void dso__data_close(struct dso *dso)
653 {
654 	pthread_mutex_lock(&dso__data_open_lock);
655 	close_dso(dso);
656 	pthread_mutex_unlock(&dso__data_open_lock);
657 }
658 
659 static void try_to_open_dso(struct dso *dso, struct machine *machine)
660 {
661 	enum dso_binary_type binary_type_data[] = {
662 		DSO_BINARY_TYPE__BUILD_ID_CACHE,
663 		DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
664 		DSO_BINARY_TYPE__NOT_FOUND,
665 	};
666 	int i = 0;
667 
668 	if (dso->data.fd >= 0)
669 		return;
670 
671 	if (dso->binary_type != DSO_BINARY_TYPE__NOT_FOUND) {
672 		dso->data.fd = open_dso(dso, machine);
673 		goto out;
674 	}
675 
676 	do {
677 		dso->binary_type = binary_type_data[i++];
678 
679 		dso->data.fd = open_dso(dso, machine);
680 		if (dso->data.fd >= 0)
681 			goto out;
682 
683 	} while (dso->binary_type != DSO_BINARY_TYPE__NOT_FOUND);
684 out:
685 	if (dso->data.fd >= 0)
686 		dso->data.status = DSO_DATA_STATUS_OK;
687 	else
688 		dso->data.status = DSO_DATA_STATUS_ERROR;
689 }
690 
691 /**
692  * dso__data_get_fd - Get dso's data file descriptor
693  * @dso: dso object
694  * @machine: machine object
695  *
696  * External interface to find dso's file, open it and
697  * returns file descriptor.  It should be paired with
698  * dso__data_put_fd() if it returns non-negative value.
699  */
700 int dso__data_get_fd(struct dso *dso, struct machine *machine)
701 {
702 	if (dso->data.status == DSO_DATA_STATUS_ERROR)
703 		return -1;
704 
705 	if (pthread_mutex_lock(&dso__data_open_lock) < 0)
706 		return -1;
707 
708 	try_to_open_dso(dso, machine);
709 
710 	if (dso->data.fd < 0)
711 		pthread_mutex_unlock(&dso__data_open_lock);
712 
713 	return dso->data.fd;
714 }
715 
716 void dso__data_put_fd(struct dso *dso __maybe_unused)
717 {
718 	pthread_mutex_unlock(&dso__data_open_lock);
719 }
720 
721 bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by)
722 {
723 	u32 flag = 1 << by;
724 
725 	if (dso->data.status_seen & flag)
726 		return true;
727 
728 	dso->data.status_seen |= flag;
729 
730 	return false;
731 }
732 
733 static ssize_t bpf_read(struct dso *dso, u64 offset, char *data)
734 {
735 	struct bpf_prog_info_node *node;
736 	ssize_t size = DSO__DATA_CACHE_SIZE;
737 	u64 len;
738 	u8 *buf;
739 
740 	node = perf_env__find_bpf_prog_info(dso->bpf_prog.env, dso->bpf_prog.id);
741 	if (!node || !node->info_linear) {
742 		dso->data.status = DSO_DATA_STATUS_ERROR;
743 		return -1;
744 	}
745 
746 	len = node->info_linear->info.jited_prog_len;
747 	buf = (u8 *)(uintptr_t)node->info_linear->info.jited_prog_insns;
748 
749 	if (offset >= len)
750 		return -1;
751 
752 	size = (ssize_t)min(len - offset, (u64)size);
753 	memcpy(data, buf + offset, size);
754 	return size;
755 }
756 
757 static int bpf_size(struct dso *dso)
758 {
759 	struct bpf_prog_info_node *node;
760 
761 	node = perf_env__find_bpf_prog_info(dso->bpf_prog.env, dso->bpf_prog.id);
762 	if (!node || !node->info_linear) {
763 		dso->data.status = DSO_DATA_STATUS_ERROR;
764 		return -1;
765 	}
766 
767 	dso->data.file_size = node->info_linear->info.jited_prog_len;
768 	return 0;
769 }
770 
771 static void
772 dso_cache__free(struct dso *dso)
773 {
774 	struct rb_root *root = &dso->data.cache;
775 	struct rb_node *next = rb_first(root);
776 
777 	pthread_mutex_lock(&dso->lock);
778 	while (next) {
779 		struct dso_cache *cache;
780 
781 		cache = rb_entry(next, struct dso_cache, rb_node);
782 		next = rb_next(&cache->rb_node);
783 		rb_erase(&cache->rb_node, root);
784 		free(cache);
785 	}
786 	pthread_mutex_unlock(&dso->lock);
787 }
788 
789 static struct dso_cache *__dso_cache__find(struct dso *dso, u64 offset)
790 {
791 	const struct rb_root *root = &dso->data.cache;
792 	struct rb_node * const *p = &root->rb_node;
793 	const struct rb_node *parent = NULL;
794 	struct dso_cache *cache;
795 
796 	while (*p != NULL) {
797 		u64 end;
798 
799 		parent = *p;
800 		cache = rb_entry(parent, struct dso_cache, rb_node);
801 		end = cache->offset + DSO__DATA_CACHE_SIZE;
802 
803 		if (offset < cache->offset)
804 			p = &(*p)->rb_left;
805 		else if (offset >= end)
806 			p = &(*p)->rb_right;
807 		else
808 			return cache;
809 	}
810 
811 	return NULL;
812 }
813 
814 static struct dso_cache *
815 dso_cache__insert(struct dso *dso, struct dso_cache *new)
816 {
817 	struct rb_root *root = &dso->data.cache;
818 	struct rb_node **p = &root->rb_node;
819 	struct rb_node *parent = NULL;
820 	struct dso_cache *cache;
821 	u64 offset = new->offset;
822 
823 	pthread_mutex_lock(&dso->lock);
824 	while (*p != NULL) {
825 		u64 end;
826 
827 		parent = *p;
828 		cache = rb_entry(parent, struct dso_cache, rb_node);
829 		end = cache->offset + DSO__DATA_CACHE_SIZE;
830 
831 		if (offset < cache->offset)
832 			p = &(*p)->rb_left;
833 		else if (offset >= end)
834 			p = &(*p)->rb_right;
835 		else
836 			goto out;
837 	}
838 
839 	rb_link_node(&new->rb_node, parent, p);
840 	rb_insert_color(&new->rb_node, root);
841 
842 	cache = NULL;
843 out:
844 	pthread_mutex_unlock(&dso->lock);
845 	return cache;
846 }
847 
848 static ssize_t dso_cache__memcpy(struct dso_cache *cache, u64 offset, u8 *data,
849 				 u64 size, bool out)
850 {
851 	u64 cache_offset = offset - cache->offset;
852 	u64 cache_size   = min(cache->size - cache_offset, size);
853 
854 	if (out)
855 		memcpy(data, cache->data + cache_offset, cache_size);
856 	else
857 		memcpy(cache->data + cache_offset, data, cache_size);
858 	return cache_size;
859 }
860 
861 static ssize_t file_read(struct dso *dso, struct machine *machine,
862 			 u64 offset, char *data)
863 {
864 	ssize_t ret;
865 
866 	pthread_mutex_lock(&dso__data_open_lock);
867 
868 	/*
869 	 * dso->data.fd might be closed if other thread opened another
870 	 * file (dso) due to open file limit (RLIMIT_NOFILE).
871 	 */
872 	try_to_open_dso(dso, machine);
873 
874 	if (dso->data.fd < 0) {
875 		dso->data.status = DSO_DATA_STATUS_ERROR;
876 		ret = -errno;
877 		goto out;
878 	}
879 
880 	ret = pread(dso->data.fd, data, DSO__DATA_CACHE_SIZE, offset);
881 out:
882 	pthread_mutex_unlock(&dso__data_open_lock);
883 	return ret;
884 }
885 
886 static struct dso_cache *dso_cache__populate(struct dso *dso,
887 					     struct machine *machine,
888 					     u64 offset, ssize_t *ret)
889 {
890 	u64 cache_offset = offset & DSO__DATA_CACHE_MASK;
891 	struct dso_cache *cache;
892 	struct dso_cache *old;
893 
894 	cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);
895 	if (!cache) {
896 		*ret = -ENOMEM;
897 		return NULL;
898 	}
899 
900 	if (dso->binary_type == DSO_BINARY_TYPE__BPF_PROG_INFO)
901 		*ret = bpf_read(dso, cache_offset, cache->data);
902 	else if (dso->binary_type == DSO_BINARY_TYPE__OOL)
903 		*ret = DSO__DATA_CACHE_SIZE;
904 	else
905 		*ret = file_read(dso, machine, cache_offset, cache->data);
906 
907 	if (*ret <= 0) {
908 		free(cache);
909 		return NULL;
910 	}
911 
912 	cache->offset = cache_offset;
913 	cache->size   = *ret;
914 
915 	old = dso_cache__insert(dso, cache);
916 	if (old) {
917 		/* we lose the race */
918 		free(cache);
919 		cache = old;
920 	}
921 
922 	return cache;
923 }
924 
925 static struct dso_cache *dso_cache__find(struct dso *dso,
926 					 struct machine *machine,
927 					 u64 offset,
928 					 ssize_t *ret)
929 {
930 	struct dso_cache *cache = __dso_cache__find(dso, offset);
931 
932 	return cache ? cache : dso_cache__populate(dso, machine, offset, ret);
933 }
934 
935 static ssize_t dso_cache_io(struct dso *dso, struct machine *machine,
936 			    u64 offset, u8 *data, ssize_t size, bool out)
937 {
938 	struct dso_cache *cache;
939 	ssize_t ret = 0;
940 
941 	cache = dso_cache__find(dso, machine, offset, &ret);
942 	if (!cache)
943 		return ret;
944 
945 	return dso_cache__memcpy(cache, offset, data, size, out);
946 }
947 
948 /*
949  * Reads and caches dso data DSO__DATA_CACHE_SIZE size chunks
950  * in the rb_tree. Any read to already cached data is served
951  * by cached data. Writes update the cache only, not the backing file.
952  */
953 static ssize_t cached_io(struct dso *dso, struct machine *machine,
954 			 u64 offset, u8 *data, ssize_t size, bool out)
955 {
956 	ssize_t r = 0;
957 	u8 *p = data;
958 
959 	do {
960 		ssize_t ret;
961 
962 		ret = dso_cache_io(dso, machine, offset, p, size, out);
963 		if (ret < 0)
964 			return ret;
965 
966 		/* Reached EOF, return what we have. */
967 		if (!ret)
968 			break;
969 
970 		BUG_ON(ret > size);
971 
972 		r      += ret;
973 		p      += ret;
974 		offset += ret;
975 		size   -= ret;
976 
977 	} while (size);
978 
979 	return r;
980 }
981 
982 static int file_size(struct dso *dso, struct machine *machine)
983 {
984 	int ret = 0;
985 	struct stat st;
986 	char sbuf[STRERR_BUFSIZE];
987 
988 	pthread_mutex_lock(&dso__data_open_lock);
989 
990 	/*
991 	 * dso->data.fd might be closed if other thread opened another
992 	 * file (dso) due to open file limit (RLIMIT_NOFILE).
993 	 */
994 	try_to_open_dso(dso, machine);
995 
996 	if (dso->data.fd < 0) {
997 		ret = -errno;
998 		dso->data.status = DSO_DATA_STATUS_ERROR;
999 		goto out;
1000 	}
1001 
1002 	if (fstat(dso->data.fd, &st) < 0) {
1003 		ret = -errno;
1004 		pr_err("dso cache fstat failed: %s\n",
1005 		       str_error_r(errno, sbuf, sizeof(sbuf)));
1006 		dso->data.status = DSO_DATA_STATUS_ERROR;
1007 		goto out;
1008 	}
1009 	dso->data.file_size = st.st_size;
1010 
1011 out:
1012 	pthread_mutex_unlock(&dso__data_open_lock);
1013 	return ret;
1014 }
1015 
1016 int dso__data_file_size(struct dso *dso, struct machine *machine)
1017 {
1018 	if (dso->data.file_size)
1019 		return 0;
1020 
1021 	if (dso->data.status == DSO_DATA_STATUS_ERROR)
1022 		return -1;
1023 
1024 	if (dso->binary_type == DSO_BINARY_TYPE__BPF_PROG_INFO)
1025 		return bpf_size(dso);
1026 
1027 	return file_size(dso, machine);
1028 }
1029 
1030 /**
1031  * dso__data_size - Return dso data size
1032  * @dso: dso object
1033  * @machine: machine object
1034  *
1035  * Return: dso data size
1036  */
1037 off_t dso__data_size(struct dso *dso, struct machine *machine)
1038 {
1039 	if (dso__data_file_size(dso, machine))
1040 		return -1;
1041 
1042 	/* For now just estimate dso data size is close to file size */
1043 	return dso->data.file_size;
1044 }
1045 
1046 static ssize_t data_read_write_offset(struct dso *dso, struct machine *machine,
1047 				      u64 offset, u8 *data, ssize_t size,
1048 				      bool out)
1049 {
1050 	if (dso__data_file_size(dso, machine))
1051 		return -1;
1052 
1053 	/* Check the offset sanity. */
1054 	if (offset > dso->data.file_size)
1055 		return -1;
1056 
1057 	if (offset + size < offset)
1058 		return -1;
1059 
1060 	return cached_io(dso, machine, offset, data, size, out);
1061 }
1062 
1063 /**
1064  * dso__data_read_offset - Read data from dso file offset
1065  * @dso: dso object
1066  * @machine: machine object
1067  * @offset: file offset
1068  * @data: buffer to store data
1069  * @size: size of the @data buffer
1070  *
1071  * External interface to read data from dso file offset. Open
1072  * dso data file and use cached_read to get the data.
1073  */
1074 ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
1075 			      u64 offset, u8 *data, ssize_t size)
1076 {
1077 	if (dso->data.status == DSO_DATA_STATUS_ERROR)
1078 		return -1;
1079 
1080 	return data_read_write_offset(dso, machine, offset, data, size, true);
1081 }
1082 
1083 /**
1084  * dso__data_read_addr - Read data from dso address
1085  * @dso: dso object
1086  * @machine: machine object
1087  * @add: virtual memory address
1088  * @data: buffer to store data
1089  * @size: size of the @data buffer
1090  *
1091  * External interface to read data from dso address.
1092  */
1093 ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
1094 			    struct machine *machine, u64 addr,
1095 			    u8 *data, ssize_t size)
1096 {
1097 	u64 offset = map->map_ip(map, addr);
1098 	return dso__data_read_offset(dso, machine, offset, data, size);
1099 }
1100 
1101 /**
1102  * dso__data_write_cache_offs - Write data to dso data cache at file offset
1103  * @dso: dso object
1104  * @machine: machine object
1105  * @offset: file offset
1106  * @data: buffer to write
1107  * @size: size of the @data buffer
1108  *
1109  * Write into the dso file data cache, but do not change the file itself.
1110  */
1111 ssize_t dso__data_write_cache_offs(struct dso *dso, struct machine *machine,
1112 				   u64 offset, const u8 *data_in, ssize_t size)
1113 {
1114 	u8 *data = (u8 *)data_in; /* cast away const to use same fns for r/w */
1115 
1116 	if (dso->data.status == DSO_DATA_STATUS_ERROR)
1117 		return -1;
1118 
1119 	return data_read_write_offset(dso, machine, offset, data, size, false);
1120 }
1121 
1122 /**
1123  * dso__data_write_cache_addr - Write data to dso data cache at dso address
1124  * @dso: dso object
1125  * @machine: machine object
1126  * @add: virtual memory address
1127  * @data: buffer to write
1128  * @size: size of the @data buffer
1129  *
1130  * External interface to write into the dso file data cache, but do not change
1131  * the file itself.
1132  */
1133 ssize_t dso__data_write_cache_addr(struct dso *dso, struct map *map,
1134 				   struct machine *machine, u64 addr,
1135 				   const u8 *data, ssize_t size)
1136 {
1137 	u64 offset = map->map_ip(map, addr);
1138 	return dso__data_write_cache_offs(dso, machine, offset, data, size);
1139 }
1140 
1141 struct map *dso__new_map(const char *name)
1142 {
1143 	struct map *map = NULL;
1144 	struct dso *dso = dso__new(name);
1145 
1146 	if (dso)
1147 		map = map__new2(0, dso);
1148 
1149 	return map;
1150 }
1151 
1152 struct dso *machine__findnew_kernel(struct machine *machine, const char *name,
1153 				    const char *short_name, int dso_type)
1154 {
1155 	/*
1156 	 * The kernel dso could be created by build_id processing.
1157 	 */
1158 	struct dso *dso = machine__findnew_dso(machine, name);
1159 
1160 	/*
1161 	 * We need to run this in all cases, since during the build_id
1162 	 * processing we had no idea this was the kernel dso.
1163 	 */
1164 	if (dso != NULL) {
1165 		dso__set_short_name(dso, short_name, false);
1166 		dso->kernel = dso_type;
1167 	}
1168 
1169 	return dso;
1170 }
1171 
1172 static void dso__set_long_name_id(struct dso *dso, const char *name, struct dso_id *id, bool name_allocated)
1173 {
1174 	struct rb_root *root = dso->root;
1175 
1176 	if (name == NULL)
1177 		return;
1178 
1179 	if (dso->long_name_allocated)
1180 		free((char *)dso->long_name);
1181 
1182 	if (root) {
1183 		rb_erase(&dso->rb_node, root);
1184 		/*
1185 		 * __dsos__findnew_link_by_longname_id() isn't guaranteed to
1186 		 * add it back, so a clean removal is required here.
1187 		 */
1188 		RB_CLEAR_NODE(&dso->rb_node);
1189 		dso->root = NULL;
1190 	}
1191 
1192 	dso->long_name		 = name;
1193 	dso->long_name_len	 = strlen(name);
1194 	dso->long_name_allocated = name_allocated;
1195 
1196 	if (root)
1197 		__dsos__findnew_link_by_longname_id(root, dso, NULL, id);
1198 }
1199 
1200 void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
1201 {
1202 	dso__set_long_name_id(dso, name, NULL, name_allocated);
1203 }
1204 
1205 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
1206 {
1207 	if (name == NULL)
1208 		return;
1209 
1210 	if (dso->short_name_allocated)
1211 		free((char *)dso->short_name);
1212 
1213 	dso->short_name		  = name;
1214 	dso->short_name_len	  = strlen(name);
1215 	dso->short_name_allocated = name_allocated;
1216 }
1217 
1218 int dso__name_len(const struct dso *dso)
1219 {
1220 	if (!dso)
1221 		return strlen("[unknown]");
1222 	if (verbose > 0)
1223 		return dso->long_name_len;
1224 
1225 	return dso->short_name_len;
1226 }
1227 
1228 bool dso__loaded(const struct dso *dso)
1229 {
1230 	return dso->loaded;
1231 }
1232 
1233 bool dso__sorted_by_name(const struct dso *dso)
1234 {
1235 	return dso->sorted_by_name;
1236 }
1237 
1238 void dso__set_sorted_by_name(struct dso *dso)
1239 {
1240 	dso->sorted_by_name = true;
1241 }
1242 
1243 struct dso *dso__new_id(const char *name, struct dso_id *id)
1244 {
1245 	struct dso *dso = calloc(1, sizeof(*dso) + strlen(name) + 1);
1246 
1247 	if (dso != NULL) {
1248 		strcpy(dso->name, name);
1249 		if (id)
1250 			dso->id = *id;
1251 		dso__set_long_name_id(dso, dso->name, id, false);
1252 		dso__set_short_name(dso, dso->name, false);
1253 		dso->symbols = dso->symbol_names = RB_ROOT_CACHED;
1254 		dso->data.cache = RB_ROOT;
1255 		dso->inlined_nodes = RB_ROOT_CACHED;
1256 		dso->srclines = RB_ROOT_CACHED;
1257 		dso->data.fd = -1;
1258 		dso->data.status = DSO_DATA_STATUS_UNKNOWN;
1259 		dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND;
1260 		dso->binary_type = DSO_BINARY_TYPE__NOT_FOUND;
1261 		dso->is_64_bit = (sizeof(void *) == 8);
1262 		dso->loaded = 0;
1263 		dso->rel = 0;
1264 		dso->sorted_by_name = 0;
1265 		dso->has_build_id = 0;
1266 		dso->has_srcline = 1;
1267 		dso->a2l_fails = 1;
1268 		dso->kernel = DSO_SPACE__USER;
1269 		dso->needs_swap = DSO_SWAP__UNSET;
1270 		dso->comp = COMP_ID__NONE;
1271 		RB_CLEAR_NODE(&dso->rb_node);
1272 		dso->root = NULL;
1273 		INIT_LIST_HEAD(&dso->node);
1274 		INIT_LIST_HEAD(&dso->data.open_entry);
1275 		pthread_mutex_init(&dso->lock, NULL);
1276 		refcount_set(&dso->refcnt, 1);
1277 	}
1278 
1279 	return dso;
1280 }
1281 
1282 struct dso *dso__new(const char *name)
1283 {
1284 	return dso__new_id(name, NULL);
1285 }
1286 
1287 void dso__delete(struct dso *dso)
1288 {
1289 	if (!RB_EMPTY_NODE(&dso->rb_node))
1290 		pr_err("DSO %s is still in rbtree when being deleted!\n",
1291 		       dso->long_name);
1292 
1293 	/* free inlines first, as they reference symbols */
1294 	inlines__tree_delete(&dso->inlined_nodes);
1295 	srcline__tree_delete(&dso->srclines);
1296 	symbols__delete(&dso->symbols);
1297 
1298 	if (dso->short_name_allocated) {
1299 		zfree((char **)&dso->short_name);
1300 		dso->short_name_allocated = false;
1301 	}
1302 
1303 	if (dso->long_name_allocated) {
1304 		zfree((char **)&dso->long_name);
1305 		dso->long_name_allocated = false;
1306 	}
1307 
1308 	dso__data_close(dso);
1309 	auxtrace_cache__free(dso->auxtrace_cache);
1310 	dso_cache__free(dso);
1311 	dso__free_a2l(dso);
1312 	zfree(&dso->symsrc_filename);
1313 	nsinfo__zput(dso->nsinfo);
1314 	pthread_mutex_destroy(&dso->lock);
1315 	free(dso);
1316 }
1317 
1318 struct dso *dso__get(struct dso *dso)
1319 {
1320 	if (dso)
1321 		refcount_inc(&dso->refcnt);
1322 	return dso;
1323 }
1324 
1325 void dso__put(struct dso *dso)
1326 {
1327 	if (dso && refcount_dec_and_test(&dso->refcnt))
1328 		dso__delete(dso);
1329 }
1330 
1331 void dso__set_build_id(struct dso *dso, void *build_id)
1332 {
1333 	memcpy(dso->build_id, build_id, sizeof(dso->build_id));
1334 	dso->has_build_id = 1;
1335 }
1336 
1337 bool dso__build_id_equal(const struct dso *dso, u8 *build_id)
1338 {
1339 	return memcmp(dso->build_id, build_id, sizeof(dso->build_id)) == 0;
1340 }
1341 
1342 void dso__read_running_kernel_build_id(struct dso *dso, struct machine *machine)
1343 {
1344 	char path[PATH_MAX];
1345 
1346 	if (machine__is_default_guest(machine))
1347 		return;
1348 	sprintf(path, "%s/sys/kernel/notes", machine->root_dir);
1349 	if (sysfs__read_build_id(path, dso->build_id,
1350 				 sizeof(dso->build_id)) == 0)
1351 		dso->has_build_id = true;
1352 }
1353 
1354 int dso__kernel_module_get_build_id(struct dso *dso,
1355 				    const char *root_dir)
1356 {
1357 	char filename[PATH_MAX];
1358 	/*
1359 	 * kernel module short names are of the form "[module]" and
1360 	 * we need just "module" here.
1361 	 */
1362 	const char *name = dso->short_name + 1;
1363 
1364 	snprintf(filename, sizeof(filename),
1365 		 "%s/sys/module/%.*s/notes/.note.gnu.build-id",
1366 		 root_dir, (int)strlen(name) - 1, name);
1367 
1368 	if (sysfs__read_build_id(filename, dso->build_id,
1369 				 sizeof(dso->build_id)) == 0)
1370 		dso->has_build_id = true;
1371 
1372 	return 0;
1373 }
1374 
1375 size_t dso__fprintf_buildid(struct dso *dso, FILE *fp)
1376 {
1377 	char sbuild_id[SBUILD_ID_SIZE];
1378 
1379 	build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
1380 	return fprintf(fp, "%s", sbuild_id);
1381 }
1382 
1383 size_t dso__fprintf(struct dso *dso, FILE *fp)
1384 {
1385 	struct rb_node *nd;
1386 	size_t ret = fprintf(fp, "dso: %s (", dso->short_name);
1387 
1388 	if (dso->short_name != dso->long_name)
1389 		ret += fprintf(fp, "%s, ", dso->long_name);
1390 	ret += fprintf(fp, "%sloaded, ", dso__loaded(dso) ? "" : "NOT ");
1391 	ret += dso__fprintf_buildid(dso, fp);
1392 	ret += fprintf(fp, ")\n");
1393 	for (nd = rb_first_cached(&dso->symbols); nd; nd = rb_next(nd)) {
1394 		struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
1395 		ret += symbol__fprintf(pos, fp);
1396 	}
1397 
1398 	return ret;
1399 }
1400 
1401 enum dso_type dso__type(struct dso *dso, struct machine *machine)
1402 {
1403 	int fd;
1404 	enum dso_type type = DSO__TYPE_UNKNOWN;
1405 
1406 	fd = dso__data_get_fd(dso, machine);
1407 	if (fd >= 0) {
1408 		type = dso__type_fd(fd);
1409 		dso__data_put_fd(dso);
1410 	}
1411 
1412 	return type;
1413 }
1414 
1415 int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
1416 {
1417 	int idx, errnum = dso->load_errno;
1418 	/*
1419 	 * This must have a same ordering as the enum dso_load_errno.
1420 	 */
1421 	static const char *dso_load__error_str[] = {
1422 	"Internal tools/perf/ library error",
1423 	"Invalid ELF file",
1424 	"Can not read build id",
1425 	"Mismatching build id",
1426 	"Decompression failure",
1427 	};
1428 
1429 	BUG_ON(buflen == 0);
1430 
1431 	if (errnum >= 0) {
1432 		const char *err = str_error_r(errnum, buf, buflen);
1433 
1434 		if (err != buf)
1435 			scnprintf(buf, buflen, "%s", err);
1436 
1437 		return 0;
1438 	}
1439 
1440 	if (errnum <  __DSO_LOAD_ERRNO__START || errnum >= __DSO_LOAD_ERRNO__END)
1441 		return -1;
1442 
1443 	idx = errnum - __DSO_LOAD_ERRNO__START;
1444 	scnprintf(buf, buflen, "%s", dso_load__error_str[idx]);
1445 	return 0;
1446 }
1447