summaryrefslogtreecommitdiffstats
path: root/lib/procfs.c
blob: 59f40ffbb0552b30fa284a9da0d9bde70f9fc660 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
/*
 * No copyright is claimed.  This code is in the public domain; do with
 * it what you wish.
 *
 * Copyright (C) 2021 Karel Zak <kzak@redhat.com>
 */
#include <ctype.h>
#include <unistd.h>
#include <errno.h>

#ifdef HAVE_SYS_VFS_H
# include <sys/vfs.h>
# include "statfs_magic.h"
#endif

#include "c.h"
#include "pathnames.h"
#include "procfs.h"
#include "fileutils.h"
#include "all-io.h"
#include "debug.h"
#include "strutils.h"

static void procfs_process_deinit_path(struct path_cxt *pc);

/*
 * Debug stuff (based on include/debug.h)
 */
static UL_DEBUG_DEFINE_MASK(ulprocfs);
UL_DEBUG_DEFINE_MASKNAMES(ulprocfs) = UL_DEBUG_EMPTY_MASKNAMES;

#define ULPROCFS_DEBUG_INIT	(1 << 1)
#define ULPROCFS_DEBUG_CXT	(1 << 2)

#define DBG(m, x)       __UL_DBG(ulprocfs, ULPROCFS_DEBUG_, m, x)
#define ON_DBG(m, x)    __UL_DBG_CALL(ulprocfs, ULPROCFS_DEBUG_, m, x)

#define UL_DEBUG_CURRENT_MASK	UL_DEBUG_MASK(ulprocfs)
#include "debugobj.h"

void ul_procfs_init_debug(void)
{
	if (ulprocfs_debug_mask)
		return;
	__UL_INIT_DEBUG_FROM_ENV(ulprocfs, ULPROCFS_DEBUG_, 0, ULPROCFS_DEBUG);
}

struct path_cxt *ul_new_procfs_path(pid_t pid, const char *prefix)
{
	struct path_cxt *pc = ul_new_path(NULL);

	if (!pc)
		return NULL;
	if (prefix)
		ul_path_set_prefix(pc, prefix);

	if (procfs_process_init_path(pc, pid) != 0) {
		ul_unref_path(pc);
		return NULL;
	}

	DBG(CXT, ul_debugobj(pc, "alloc"));
	return pc;
}

/*
 * procfs_blkdev_* is procfs extension to ul_path_* API to read info about process.
 *
 * The function is possible to call in loop and without sysfs_procfs_deinit_path().
 * The procfs_process_deinit_path() is automatically called by ul_unref_path().
 *
 */
int procfs_process_init_path(struct path_cxt *pc, pid_t pid)
{
	struct procfs_process *prc;
	int rc;
	char buf[sizeof(_PATH_PROC) + sizeof(stringify_value(UINT32_MAX)) + 2];

	/* define path to pid stuff */
	snprintf(buf, sizeof(buf), _PATH_PROC "/%zu", (size_t) pid);
	rc = ul_path_set_dir(pc, buf);
	if (rc)
		return rc;

	/* make sure path exists */
	rc = ul_path_get_dirfd(pc);
	if (rc < 0)
		return rc;

	/* initialize procfs specific stuff */
	prc = ul_path_get_dialect(pc);
	if (!prc) {
		DBG(CXT, ul_debugobj(pc, "alloc new procfs handler"));
		prc = calloc(1, sizeof(struct procfs_process));
		if (!prc)
			return -ENOMEM;

		ul_path_set_dialect(pc, prc, procfs_process_deinit_path);
	}

	DBG(CXT, ul_debugobj(pc, "init procfs stuff"));

	prc->pid = pid;
	return 0;
}

static void procfs_process_deinit_path(struct path_cxt *pc)
{
	struct procfs_process *prc;

	if (!pc)
		return;

	DBG(CXT, ul_debugobj(pc, "deinit"));

	prc = ul_path_get_dialect(pc);
	if (!prc)
		return;

	free(prc);
	ul_path_set_dialect(pc, NULL, NULL);
}

static ssize_t read_procfs_file(int fd, char *buf, size_t bufsz)
{
	ssize_t sz = 0;
	size_t i;

	if (fd < 0)
		return -EINVAL;

	sz = read_all(fd, buf, bufsz);
	if (sz <= 0)
		return sz;

	for (i = 0; i < (size_t) sz; i++) {
		if (buf[i] == '\0')
			buf[i] = ' ';
	}
	buf[sz - 1] = '\0';
	return sz;
}

static ssize_t procfs_process_get_data_for(struct path_cxt *pc, char *buf, size_t bufsz,
					    const char *fname)
{
	int fd = ul_path_open(pc, O_RDONLY|O_CLOEXEC, fname);

	if (fd >= 0) {
		ssize_t sz = read_procfs_file(fd, buf, bufsz);
		close(fd);
		return sz;
	}
	return -errno;
}

ssize_t procfs_process_get_cmdline(struct path_cxt *pc, char *buf, size_t bufsz)
{
	return procfs_process_get_data_for(pc, buf, bufsz, "cmdline");
}

ssize_t procfs_process_get_cmdname(struct path_cxt *pc, char *buf, size_t bufsz)
{
	return procfs_process_get_data_for(pc, buf, bufsz, "comm");
}

ssize_t procfs_process_get_stat(struct path_cxt *pc, char *buf, size_t bufsz)
{
	return procfs_process_get_data_for(pc, buf, bufsz, "stat");
}

ssize_t procfs_process_get_syscall(struct path_cxt *pc, char *buf, size_t bufsz)
{
	return procfs_process_get_data_for(pc, buf, bufsz, "syscall");
}

int procfs_process_get_stat_nth(struct path_cxt *pc, int n, uintmax_t *re)
{
	ssize_t rc;
	char *key = NULL, *tok, *p;
	char buf[BUFSIZ];
	int i;

	if (n == 2 || n == 3)		/* process name and status (strings) */
		return -EINVAL;

	rc = procfs_process_get_data_for(pc, buf, sizeof(buf), "stat");
	if (rc < 0)
		return rc;

	for (i = 0, tok = strtok_r(buf, " ", &key); tok;
	     tok = strtok_r(NULL, " ", &key)) {

		i++;
		if (i == n)
			return ul_strtou64(tok, re, 10);

		/* skip rest of the process name */
		if (i == 2 && (p = strrchr(key, ')')))
			key = p + 2;
	}

	return -EINVAL;
}

int procfs_process_get_uid(struct path_cxt *pc, uid_t *uid)
{
	struct stat sb;
	int rc;

	if ((rc = ul_path_stat(pc, &sb, 0, NULL)) == 0)
		*uid = sb.st_uid;
	return rc;
}

/*
 * returns the next task TID, the @sub is automatically initialized
 * when called first time and closed after last call or you can
 * call closedir()* when you need to break the loop.
 *
 * Returns: <0 on error, 0 on success, >1 done
 *
 * Example:
 *
 * pid_t tid;
 * DIR *sub = NULL;
 * path_cxt *pc = ul_new_procfs_path(123, NULL);
 *
 * while (procfs_process_next_tid(pc, &sub, &tid) == 0)
 *	printf("task: %d", (int) tid);
 *
 */
int procfs_process_next_tid(struct path_cxt *pc, DIR **sub, pid_t *tid)
{
	struct dirent *d;

	if (!pc || !sub || !tid)
		return -EINVAL;

	if (!*sub) {
		*sub = ul_path_opendir(pc, "task");
		if (!*sub)
			return -errno;
	}

	while ((d = xreaddir(*sub))) {
		if (procfs_dirent_get_pid(d, tid) == 0)
			return 0;
	}

	closedir(*sub);
	*sub = NULL;
	return 1;
}

int procfs_process_next_fd(struct path_cxt *pc, DIR **sub, int *fd)
{
	struct dirent *d;

	if (!pc || !sub || !fd)
		return -EINVAL;

	if (!*sub) {
		*sub = ul_path_opendir(pc, "fd");
		if (!*sub)
			return -errno;
	}

	while ((d = xreaddir(*sub))) {
		uint64_t num;
#ifdef _DIRENT_HAVE_D_TYPE
		if (d->d_type != DT_LNK && d->d_type != DT_UNKNOWN)
			continue;
#endif
		if (ul_strtou64(d->d_name, &num, 10) < 0)
			continue;
		*fd = num;
		return 0;
	}

	closedir(*sub);
	*sub = NULL;
	return 1;
}

/*
 * Simple 'dirent' based stuff for use-cases where procfs_process_* API is overkill
 */

/* stupid, but good enough as a basic filter */
int procfs_dirent_is_process(struct dirent *d)
{
#ifdef _DIRENT_HAVE_D_TYPE
	if (d->d_type != DT_DIR && d->d_type != DT_UNKNOWN)
		return 0;
#endif
	if (!isdigit((unsigned char) *d->d_name))
		return 0;

	return 1;
}

int procfs_dirent_get_pid(struct dirent *d, pid_t *pid)
{
	uint64_t num;

	if (!procfs_dirent_is_process(d))
		return -EINVAL;

	if (ul_strtou64(d->d_name, &num, 10) < 0)
		return -EINVAL;

	*pid = (pid_t) num;
	return 0;
}

int procfs_dirent_get_uid(DIR *procfs, struct dirent *d, uid_t *uid)
{
	struct stat st;

	if (!procfs_dirent_is_process(d))
		return -EINVAL;

	if (fstatat(dirfd(procfs), d->d_name, &st, 0))
		return -EINVAL;

	*uid = st.st_uid;
	return 0;
}

int procfs_dirent_match_uid(DIR *procfs, struct dirent *d, uid_t uid)
{
	uid_t x;

	if (procfs_dirent_get_uid(procfs, d, &x) == 0)
		return x == uid;

	return 0;
}

/* "name" of process; may be truncated, see prctl(2) and PR_SET_NAME.
 * The minimal of the @buf has to be 32 bytes. */
int procfs_dirent_get_name(DIR *procfs, struct dirent *d, char *buf, size_t bufsz)
{
	FILE *f;
	size_t sz;
	char tmp[1024], *p, *end = NULL;

	if (bufsz < 32)
		return -EINVAL;
	if (!procfs_dirent_is_process(d))
		return -EINVAL;

	snprintf(tmp, sizeof(tmp), "%s/stat", d->d_name);
	f = fopen_at(dirfd(procfs), tmp, O_CLOEXEC|O_RDONLY, "r");
	if (!f)
		return -errno;

	p = fgets(tmp, sizeof(tmp), f);
	fclose(f);
	if (!p)
		return -errno;

	/* skip PID */
	while (*p && *p != '(')
		p++;

	/* skip extra '(' */
	while (*p && *p == '(')
		p++;

	end = p;
	while (*end && *end != ')')
		end++;

	sz = end - p;
	if (sz >= bufsz)
		sz = bufsz - 1;

	memcpy(buf, p, sz);
	buf[sz] = '\0';

	return 0;
}

int procfs_dirent_match_name(DIR *procfs, struct dirent *d, const char *name)
{
	char buf[33];

	if (procfs_dirent_get_name(procfs, d, buf, sizeof(buf)) == 0)
		return strcmp(name, buf) == 0;

	return 0;
}

#ifdef HAVE_SYS_VFS_H
/* checks if fd is file in a procfs;
 * returns 1 if true, 0 if false or couldn't determine */
int fd_is_procfs(int fd)
{
	struct statfs st;
	int ret;

	do {
		errno = 0;
		ret = fstatfs(fd, &st);

		if (ret < 0) {
			if (errno != EINTR && errno != EAGAIN)
				return 0;
			xusleep(250000);
		}
	} while (ret != 0);

	return st.f_type == STATFS_PROC_MAGIC;
	return 0;
}
#else
int fd_is_procfs(int fd __attribute__((__unused__)))
{
	return 0;
}
#endif

static char *strdup_procfs_file(pid_t pid, const char *name)
{
	char buf[BUFSIZ];
	char *re = NULL;
	int fd;

	snprintf(buf, sizeof(buf), _PATH_PROC "/%d/%s", (int) pid, name);
	fd = open(buf, O_CLOEXEC|O_RDONLY);
	if (fd < 0)
		return NULL;

	if (read_procfs_file(fd, buf, sizeof(buf)) > 0)
		re = strdup(buf);
	close(fd);
	return re;
}

char *pid_get_cmdname(pid_t pid)
{
	return strdup_procfs_file(pid, "comm");
}

char *pid_get_cmdline(pid_t pid)
{
	return strdup_procfs_file(pid, "cmdline");
}

#ifdef TEST_PROGRAM_PROCFS

static int test_tasks(int argc, char *argv[], const char *prefix)
{
	DIR *sub = NULL;
	struct path_cxt *pc;
	pid_t tid = 0, pid;

	if (argc != 2)
		return EXIT_FAILURE;

	pid = strtol(argv[1], (char **) NULL, 10);
	printf("PID=%d, TIDs:", pid);

	pc = ul_new_procfs_path(pid, prefix);
	if (!pc)
		err(EXIT_FAILURE, "alloc procfs handler failed");

	while (procfs_process_next_tid(pc, &sub, &tid) == 0)
		printf(" %d", tid);

	printf("\n");
        ul_unref_path(pc);
	return EXIT_SUCCESS;
}

static int test_fds(int argc, char *argv[], const char *prefix)
{
	DIR *sub = NULL;
	struct path_cxt *pc;
	pid_t pid;
	int fd = -1;

	if (argc != 2)
		return EXIT_FAILURE;

	pid = strtol(argv[1], (char **) NULL, 10);
	printf("PID=%d, FDs:", pid);

	pc = ul_new_procfs_path(pid, prefix);
	if (!pc)
		err(EXIT_FAILURE, "alloc procfs handler failed");

	while (procfs_process_next_fd(pc, &sub, &fd) == 0)
		printf(" %d", fd);

	fputc('\n', stdout);
        ul_unref_path(pc);
	return EXIT_SUCCESS;
}

static int test_processes(int argc, char *argv[])
{
	DIR *dir;
	struct dirent *d;
	char *name = NULL;
	uid_t uid = (uid_t) -1;
	char buf[128];

	if (argc >= 3 && strcmp(argv[1], "--name") == 0)
		name = argv[2];
	if (argc >= 3 && strcmp(argv[1], "--uid") == 0)
		uid = (uid_t) atol(argv[2]);

	dir = opendir(_PATH_PROC);
	if (!dir)
		err(EXIT_FAILURE, "cannot open proc");

	while ((d = xreaddir(dir))) {
		pid_t pid = 0;

		if (procfs_dirent_get_pid(d, &pid) != 0)
			continue;
		if (name && !procfs_dirent_match_name(dir, d, name))
			continue;
		if (uid != (uid_t) -1 && !procfs_dirent_match_uid(dir, d, uid))
			continue;
		procfs_dirent_get_name(dir, d, buf, sizeof(buf));
		printf(" %d [%s]", pid, buf);
	}

	fputc('\n', stdout);
	closedir(dir);
	return EXIT_SUCCESS;
}

static int test_one_process(int argc, char *argv[], const char *prefix)
{
	pid_t pid;
	struct path_cxt *pc;
	char buf[BUFSIZ];
	uid_t uid = (uid_t) -1;

	if (argc != 2)
		return EXIT_FAILURE;
	pid = strtol(argv[1], (char **) NULL, 10);

	pc = ul_new_procfs_path(pid, prefix);
	if (!pc)
		err(EXIT_FAILURE, "cannot alloc procfs handler");

	printf("%d\n", (int) pid);

	procfs_process_get_uid(pc, &uid);
	printf("   UID: %zu\n", (size_t) uid);

	procfs_process_get_cmdline(pc, buf, sizeof(buf));
	printf("   CMDLINE: '%s'\n", buf);

	procfs_process_get_cmdname(pc, buf, sizeof(buf));
	printf("   COMM: '%s'\n", buf);

	ul_unref_path(pc);
	return EXIT_SUCCESS;
}

static int test_isprocfs(int argc, char *argv[])
{
	const char *name = argc > 1 ? argv[1] : "/proc";
	int fd = open(name, O_RDONLY);
	int is = 0;

	if (fd >= 0) {
		is = fd_is_procfs(fd);
		close(fd);
	} else
		err(EXIT_FAILURE, "cannot open %s", name);

	printf("%s: %s procfs\n", name, is ? "is" : "is NOT");
	return is ? EXIT_SUCCESS : EXIT_FAILURE;
}

static int test_process_stat_nth(int argc, char *argv[], const char *prefix)
{
	pid_t pid;
	struct path_cxt *pc;
	uintmax_t num = 0;
	int n, ret;

	if (argc != 3)
		return EXIT_FAILURE;
	pid = strtol(argv[1], (char **) NULL, 10);
	n = strtol(argv[2], (char **) NULL, 10);

	pc = ul_new_procfs_path(pid, prefix);
	if (!pc)
		err(EXIT_FAILURE, "cannot alloc procfs handler");

	ret = procfs_process_get_stat_nth(pc, n, &num);
	if (ret)
		errx(EXIT_FAILURE, "read %dth number failed: %s", n, strerror(-ret));

	printf("%d: %dth %ju\n", (int) pid, n, num);
	ul_unref_path(pc);
	return EXIT_SUCCESS;
}

int main(int argc, char *argv[])
{
	const char *prefix = NULL;

	if (argc > 2 && strcmp(argv[1], "--prefix") == 0) {
		prefix = argv[2];
		argc -= 2;
		argv += 2;
	}

	if (argc < 2) {
		fprintf(stderr, "usage: %1$s [--prefix <prefix>] --tasks <pid>\n"
				"       %1$s [--prefix <prefix>] --fds <pid>\n"
				"       %1$s --is-procfs [<dir>]\n"
				"       %1$s --processes [--name <name>] [--uid <uid>]\n"
				"       %1$s [--prefix <prefix>] --one <pid>\n"
				"       %1$s [--prefix <prefix>] --stat-nth <pid> <n>\n",
				program_invocation_short_name);
		return EXIT_FAILURE;
	}

	if (strcmp(argv[1], "--tasks") == 0)
		return test_tasks(argc - 1, argv + 1, prefix);
	if (strcmp(argv[1], "--fds") == 0)
		return test_fds(argc - 1, argv + 1, prefix);
	if (strcmp(argv[1], "--processes") == 0)
		return test_processes(argc - 1, argv + 1);
	if (strcmp(argv[1], "--is-procfs") == 0)
		return test_isprocfs(argc - 1, argv + 1);
	if (strcmp(argv[1], "--one") == 0)
		return test_one_process(argc - 1, argv + 1, prefix);
	if (strcmp(argv[1], "--stat-nth") == 0)
		return test_process_stat_nth(argc - 1, argv + 1, prefix);

	return EXIT_FAILURE;
}
#endif /* TEST_PROGRAM_PROCUTILS */