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1// SPDX-License-Identifier: GPL-2.0
2#include <assert.h>
3#include <ctype.h>
4#include <errno.h>
5#include <limits.h>
6#include <stdbool.h>
7#include <stdio.h>
8#include <stdlib.h>
9#include <string.h>
10#include <sys/vfs.h>
11#include <sys/types.h>
12#include <sys/stat.h>
13#include <fcntl.h>
14#include <pthread.h>
15#include <unistd.h>
16#include <sys/mount.h>
17
18#include "fs.h"
19#include "../io.h"
20#include "debug-internal.h"
21
22#define _STR(x) #x
23#define STR(x) _STR(x)
24
25#ifndef SYSFS_MAGIC
26#define SYSFS_MAGIC 0x62656572
27#endif
28
29#ifndef PROC_SUPER_MAGIC
30#define PROC_SUPER_MAGIC 0x9fa0
31#endif
32
33#ifndef DEBUGFS_MAGIC
34#define DEBUGFS_MAGIC 0x64626720
35#endif
36
37#ifndef TRACEFS_MAGIC
38#define TRACEFS_MAGIC 0x74726163
39#endif
40
41#ifndef HUGETLBFS_MAGIC
42#define HUGETLBFS_MAGIC 0x958458f6
43#endif
44
45#ifndef BPF_FS_MAGIC
46#define BPF_FS_MAGIC 0xcafe4a11
47#endif
48
49static const char * const sysfs__known_mountpoints[] = {
50 "/sys",
51 0,
52};
53
54static const char * const procfs__known_mountpoints[] = {
55 "/proc",
56 0,
57};
58
59#ifndef DEBUGFS_DEFAULT_PATH
60#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
61#endif
62
63static const char * const debugfs__known_mountpoints[] = {
64 DEBUGFS_DEFAULT_PATH,
65 "/debug",
66 0,
67};
68
69
70#ifndef TRACEFS_DEFAULT_PATH
71#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
72#endif
73
74static const char * const tracefs__known_mountpoints[] = {
75 TRACEFS_DEFAULT_PATH,
76 "/sys/kernel/debug/tracing",
77 "/tracing",
78 "/trace",
79 0,
80};
81
82static const char * const hugetlbfs__known_mountpoints[] = {
83 0,
84};
85
86static const char * const bpf_fs__known_mountpoints[] = {
87 "/sys/fs/bpf",
88 0,
89};
90
91struct fs {
92 const char * const name;
93 const char * const * const mounts;
94 char *path;
95 pthread_mutex_t mount_mutex;
96 const long magic;
97};
98
99#ifndef TRACEFS_MAGIC
100#define TRACEFS_MAGIC 0x74726163
101#endif
102
103static void fs__init_once(struct fs *fs);
104static const char *fs__mountpoint(const struct fs *fs);
105static const char *fs__mount(struct fs *fs);
106
107#define FS(lower_name, fs_name, upper_name) \
108static struct fs fs__##lower_name = { \
109 .name = #fs_name, \
110 .mounts = lower_name##__known_mountpoints, \
111 .magic = upper_name##_MAGIC, \
112 .mount_mutex = PTHREAD_MUTEX_INITIALIZER, \
113}; \
114 \
115static void lower_name##_init_once(void) \
116{ \
117 struct fs *fs = &fs__##lower_name; \
118 \
119 fs__init_once(fs); \
120} \
121 \
122const char *lower_name##__mountpoint(void) \
123{ \
124 static pthread_once_t init_once = PTHREAD_ONCE_INIT; \
125 struct fs *fs = &fs__##lower_name; \
126 \
127 pthread_once(&init_once, lower_name##_init_once); \
128 return fs__mountpoint(fs); \
129} \
130 \
131const char *lower_name##__mount(void) \
132{ \
133 const char *mountpoint = lower_name##__mountpoint(); \
134 struct fs *fs = &fs__##lower_name; \
135 \
136 if (mountpoint) \
137 return mountpoint; \
138 \
139 return fs__mount(fs); \
140} \
141 \
142bool lower_name##__configured(void) \
143{ \
144 return lower_name##__mountpoint() != NULL; \
145}
146
147FS(sysfs, sysfs, SYSFS);
148FS(procfs, procfs, PROC_SUPER);
149FS(debugfs, debugfs, DEBUGFS);
150FS(tracefs, tracefs, TRACEFS);
151FS(hugetlbfs, hugetlbfs, HUGETLBFS);
152FS(bpf_fs, bpf, BPF_FS);
153
154static bool fs__read_mounts(struct fs *fs)
155{
156 char type[100];
157 FILE *fp;
158 char path[PATH_MAX + 1];
159
160 fp = fopen("/proc/mounts", "r");
161 if (fp == NULL)
162 return false;
163
164 while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
165 path, type) == 2) {
166
167 if (strcmp(type, fs->name) == 0) {
168 fs->path = strdup(path);
169 fclose(fp);
170 return fs->path != NULL;
171 }
172 }
173 fclose(fp);
174 return false;
175}
176
177static int fs__valid_mount(const char *fs, long magic)
178{
179 struct statfs st_fs;
180
181 if (statfs(fs, &st_fs) < 0)
182 return -ENOENT;
183 else if ((long)st_fs.f_type != magic)
184 return -ENOENT;
185
186 return 0;
187}
188
189static bool fs__check_mounts(struct fs *fs)
190{
191 const char * const *ptr;
192
193 ptr = fs->mounts;
194 while (*ptr) {
195 if (fs__valid_mount(*ptr, fs->magic) == 0) {
196 fs->path = strdup(*ptr);
197 if (!fs->path)
198 return false;
199 return true;
200 }
201 ptr++;
202 }
203
204 return false;
205}
206
207static void mem_toupper(char *f, size_t len)
208{
209 while (len) {
210 *f = toupper(*f);
211 f++;
212 len--;
213 }
214}
215
216/*
217 * Check for "NAME_PATH" environment variable to override fs location (for
218 * testing). This matches the recommendation in Documentation/admin-guide/sysfs-rules.rst
219 * for SYSFS_PATH.
220 */
221static bool fs__env_override(struct fs *fs)
222{
223 char *override_path;
224 size_t name_len = strlen(fs->name);
225 /* name + "_PATH" + '\0' */
226 char upper_name[name_len + 5 + 1];
227
228 memcpy(upper_name, fs->name, name_len);
229 mem_toupper(upper_name, name_len);
230 strcpy(&upper_name[name_len], "_PATH");
231
232 override_path = getenv(upper_name);
233 if (!override_path)
234 return false;
235
236 fs->path = strdup(override_path);
237 if (!fs->path)
238 return false;
239 return true;
240}
241
242static void fs__init_once(struct fs *fs)
243{
244 if (!fs__env_override(fs) &&
245 !fs__check_mounts(fs) &&
246 !fs__read_mounts(fs)) {
247 assert(!fs->path);
248 } else {
249 assert(fs->path);
250 }
251}
252
253static const char *fs__mountpoint(const struct fs *fs)
254{
255 return fs->path;
256}
257
258static const char *mount_overload(struct fs *fs)
259{
260 size_t name_len = strlen(fs->name);
261 /* "PERF_" + name + "_ENVIRONMENT" + '\0' */
262 char upper_name[5 + name_len + 12 + 1];
263
264 snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
265 mem_toupper(upper_name, name_len);
266
267 return getenv(upper_name) ?: *fs->mounts;
268}
269
270static const char *fs__mount(struct fs *fs)
271{
272 const char *mountpoint;
273
274 pthread_mutex_lock(&fs->mount_mutex);
275
276 /* Check if path found inside the mutex to avoid races with other callers of mount. */
277 mountpoint = fs__mountpoint(fs);
278 if (mountpoint)
279 goto out;
280
281 mountpoint = mount_overload(fs);
282
283 if (mount(NULL, mountpoint, fs->name, 0, NULL) == 0 &&
284 fs__valid_mount(mountpoint, fs->magic) == 0) {
285 fs->path = strdup(mountpoint);
286 mountpoint = fs->path;
287 }
288out:
289 pthread_mutex_unlock(&fs->mount_mutex);
290 return mountpoint;
291}
292
293int filename__read_int(const char *filename, int *value)
294{
295 char line[64];
296 int fd = open(filename, O_RDONLY), err = -1;
297
298 if (fd < 0)
299 return -1;
300
301 if (read(fd, line, sizeof(line)) > 0) {
302 *value = atoi(line);
303 err = 0;
304 }
305
306 close(fd);
307 return err;
308}
309
310static int filename__read_ull_base(const char *filename,
311 unsigned long long *value, int base)
312{
313 char line[64];
314 int fd = open(filename, O_RDONLY), err = -1;
315
316 if (fd < 0)
317 return -1;
318
319 if (read(fd, line, sizeof(line)) > 0) {
320 *value = strtoull(line, NULL, base);
321 if (*value != ULLONG_MAX)
322 err = 0;
323 }
324
325 close(fd);
326 return err;
327}
328
329/*
330 * Parses @value out of @filename with strtoull.
331 * By using 16 for base to treat the number as hex.
332 */
333int filename__read_xll(const char *filename, unsigned long long *value)
334{
335 return filename__read_ull_base(filename, value, 16);
336}
337
338/*
339 * Parses @value out of @filename with strtoull.
340 * By using 0 for base, the strtoull detects the
341 * base automatically (see man strtoull).
342 */
343int filename__read_ull(const char *filename, unsigned long long *value)
344{
345 return filename__read_ull_base(filename, value, 0);
346}
347
348int filename__read_str(const char *filename, char **buf, size_t *sizep)
349{
350 struct io io;
351 char bf[128];
352 int err;
353
354 io.fd = open(filename, O_RDONLY);
355 if (io.fd < 0)
356 return -errno;
357 io__init(&io, io.fd, bf, sizeof(bf));
358 *buf = NULL;
359 err = io__getdelim(&io, buf, sizep, /*delim=*/-1);
360 if (err < 0) {
361 free(*buf);
362 *buf = NULL;
363 } else
364 err = 0;
365 close(io.fd);
366 return err;
367}
368
369int filename__write_int(const char *filename, int value)
370{
371 int fd = open(filename, O_WRONLY), err = -1;
372 char buf[64];
373
374 if (fd < 0)
375 return err;
376
377 sprintf(buf, "%d", value);
378 if (write(fd, buf, sizeof(buf)) == sizeof(buf))
379 err = 0;
380
381 close(fd);
382 return err;
383}
384
385int procfs__read_str(const char *entry, char **buf, size_t *sizep)
386{
387 char path[PATH_MAX];
388 const char *procfs = procfs__mountpoint();
389
390 if (!procfs)
391 return -1;
392
393 snprintf(path, sizeof(path), "%s/%s", procfs, entry);
394
395 return filename__read_str(path, buf, sizep);
396}
397
398static int sysfs__read_ull_base(const char *entry,
399 unsigned long long *value, int base)
400{
401 char path[PATH_MAX];
402 const char *sysfs = sysfs__mountpoint();
403
404 if (!sysfs)
405 return -1;
406
407 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
408
409 return filename__read_ull_base(path, value, base);
410}
411
412int sysfs__read_xll(const char *entry, unsigned long long *value)
413{
414 return sysfs__read_ull_base(entry, value, 16);
415}
416
417int sysfs__read_ull(const char *entry, unsigned long long *value)
418{
419 return sysfs__read_ull_base(entry, value, 0);
420}
421
422int sysfs__read_int(const char *entry, int *value)
423{
424 char path[PATH_MAX];
425 const char *sysfs = sysfs__mountpoint();
426
427 if (!sysfs)
428 return -1;
429
430 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
431
432 return filename__read_int(path, value);
433}
434
435int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
436{
437 char path[PATH_MAX];
438 const char *sysfs = sysfs__mountpoint();
439
440 if (!sysfs)
441 return -1;
442
443 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
444
445 return filename__read_str(path, buf, sizep);
446}
447
448int sysfs__read_bool(const char *entry, bool *value)
449{
450 struct io io;
451 char bf[16];
452 int ret = 0;
453 char path[PATH_MAX];
454 const char *sysfs = sysfs__mountpoint();
455
456 if (!sysfs)
457 return -1;
458
459 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
460 io.fd = open(path, O_RDONLY);
461 if (io.fd < 0)
462 return -errno;
463
464 io__init(&io, io.fd, bf, sizeof(bf));
465 switch (io__get_char(&io)) {
466 case '1':
467 case 'y':
468 case 'Y':
469 *value = true;
470 break;
471 case '0':
472 case 'n':
473 case 'N':
474 *value = false;
475 break;
476 default:
477 ret = -1;
478 }
479 close(io.fd);
480
481 return ret;
482}
483int sysctl__read_int(const char *sysctl, int *value)
484{
485 char path[PATH_MAX];
486 const char *procfs = procfs__mountpoint();
487
488 if (!procfs)
489 return -1;
490
491 snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
492
493 return filename__read_int(path, value);
494}
495
496int sysfs__write_int(const char *entry, int value)
497{
498 char path[PATH_MAX];
499 const char *sysfs = sysfs__mountpoint();
500
501 if (!sysfs)
502 return -1;
503
504 if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX)
505 return -1;
506
507 return filename__write_int(path, value);
508}
1// SPDX-License-Identifier: GPL-2.0
2#include <ctype.h>
3#include <errno.h>
4#include <limits.h>
5#include <stdbool.h>
6#include <stdio.h>
7#include <stdlib.h>
8#include <string.h>
9#include <sys/vfs.h>
10#include <sys/types.h>
11#include <sys/stat.h>
12#include <fcntl.h>
13#include <unistd.h>
14#include <sys/mount.h>
15
16#include "fs.h"
17#include "debug-internal.h"
18
19#define _STR(x) #x
20#define STR(x) _STR(x)
21
22#ifndef SYSFS_MAGIC
23#define SYSFS_MAGIC 0x62656572
24#endif
25
26#ifndef PROC_SUPER_MAGIC
27#define PROC_SUPER_MAGIC 0x9fa0
28#endif
29
30#ifndef DEBUGFS_MAGIC
31#define DEBUGFS_MAGIC 0x64626720
32#endif
33
34#ifndef TRACEFS_MAGIC
35#define TRACEFS_MAGIC 0x74726163
36#endif
37
38#ifndef HUGETLBFS_MAGIC
39#define HUGETLBFS_MAGIC 0x958458f6
40#endif
41
42#ifndef BPF_FS_MAGIC
43#define BPF_FS_MAGIC 0xcafe4a11
44#endif
45
46static const char * const sysfs__fs_known_mountpoints[] = {
47 "/sys",
48 0,
49};
50
51static const char * const procfs__known_mountpoints[] = {
52 "/proc",
53 0,
54};
55
56#ifndef DEBUGFS_DEFAULT_PATH
57#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
58#endif
59
60static const char * const debugfs__known_mountpoints[] = {
61 DEBUGFS_DEFAULT_PATH,
62 "/debug",
63 0,
64};
65
66
67#ifndef TRACEFS_DEFAULT_PATH
68#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
69#endif
70
71static const char * const tracefs__known_mountpoints[] = {
72 TRACEFS_DEFAULT_PATH,
73 "/sys/kernel/debug/tracing",
74 "/tracing",
75 "/trace",
76 0,
77};
78
79static const char * const hugetlbfs__known_mountpoints[] = {
80 0,
81};
82
83static const char * const bpf_fs__known_mountpoints[] = {
84 "/sys/fs/bpf",
85 0,
86};
87
88struct fs {
89 const char *name;
90 const char * const *mounts;
91 char path[PATH_MAX];
92 bool found;
93 bool checked;
94 long magic;
95};
96
97enum {
98 FS__SYSFS = 0,
99 FS__PROCFS = 1,
100 FS__DEBUGFS = 2,
101 FS__TRACEFS = 3,
102 FS__HUGETLBFS = 4,
103 FS__BPF_FS = 5,
104};
105
106#ifndef TRACEFS_MAGIC
107#define TRACEFS_MAGIC 0x74726163
108#endif
109
110static struct fs fs__entries[] = {
111 [FS__SYSFS] = {
112 .name = "sysfs",
113 .mounts = sysfs__fs_known_mountpoints,
114 .magic = SYSFS_MAGIC,
115 .checked = false,
116 },
117 [FS__PROCFS] = {
118 .name = "proc",
119 .mounts = procfs__known_mountpoints,
120 .magic = PROC_SUPER_MAGIC,
121 .checked = false,
122 },
123 [FS__DEBUGFS] = {
124 .name = "debugfs",
125 .mounts = debugfs__known_mountpoints,
126 .magic = DEBUGFS_MAGIC,
127 .checked = false,
128 },
129 [FS__TRACEFS] = {
130 .name = "tracefs",
131 .mounts = tracefs__known_mountpoints,
132 .magic = TRACEFS_MAGIC,
133 .checked = false,
134 },
135 [FS__HUGETLBFS] = {
136 .name = "hugetlbfs",
137 .mounts = hugetlbfs__known_mountpoints,
138 .magic = HUGETLBFS_MAGIC,
139 .checked = false,
140 },
141 [FS__BPF_FS] = {
142 .name = "bpf",
143 .mounts = bpf_fs__known_mountpoints,
144 .magic = BPF_FS_MAGIC,
145 .checked = false,
146 },
147};
148
149static bool fs__read_mounts(struct fs *fs)
150{
151 bool found = false;
152 char type[100];
153 FILE *fp;
154
155 fp = fopen("/proc/mounts", "r");
156 if (fp == NULL)
157 return NULL;
158
159 while (!found &&
160 fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
161 fs->path, type) == 2) {
162
163 if (strcmp(type, fs->name) == 0)
164 found = true;
165 }
166
167 fclose(fp);
168 fs->checked = true;
169 return fs->found = found;
170}
171
172static int fs__valid_mount(const char *fs, long magic)
173{
174 struct statfs st_fs;
175
176 if (statfs(fs, &st_fs) < 0)
177 return -ENOENT;
178 else if ((long)st_fs.f_type != magic)
179 return -ENOENT;
180
181 return 0;
182}
183
184static bool fs__check_mounts(struct fs *fs)
185{
186 const char * const *ptr;
187
188 ptr = fs->mounts;
189 while (*ptr) {
190 if (fs__valid_mount(*ptr, fs->magic) == 0) {
191 fs->found = true;
192 strcpy(fs->path, *ptr);
193 return true;
194 }
195 ptr++;
196 }
197
198 return false;
199}
200
201static void mem_toupper(char *f, size_t len)
202{
203 while (len) {
204 *f = toupper(*f);
205 f++;
206 len--;
207 }
208}
209
210/*
211 * Check for "NAME_PATH" environment variable to override fs location (for
212 * testing). This matches the recommendation in Documentation/admin-guide/sysfs-rules.rst
213 * for SYSFS_PATH.
214 */
215static bool fs__env_override(struct fs *fs)
216{
217 char *override_path;
218 size_t name_len = strlen(fs->name);
219 /* name + "_PATH" + '\0' */
220 char upper_name[name_len + 5 + 1];
221
222 memcpy(upper_name, fs->name, name_len);
223 mem_toupper(upper_name, name_len);
224 strcpy(&upper_name[name_len], "_PATH");
225
226 override_path = getenv(upper_name);
227 if (!override_path)
228 return false;
229
230 fs->found = true;
231 fs->checked = true;
232 strncpy(fs->path, override_path, sizeof(fs->path) - 1);
233 fs->path[sizeof(fs->path) - 1] = '\0';
234 return true;
235}
236
237static const char *fs__get_mountpoint(struct fs *fs)
238{
239 if (fs__env_override(fs))
240 return fs->path;
241
242 if (fs__check_mounts(fs))
243 return fs->path;
244
245 if (fs__read_mounts(fs))
246 return fs->path;
247
248 return NULL;
249}
250
251static const char *fs__mountpoint(int idx)
252{
253 struct fs *fs = &fs__entries[idx];
254
255 if (fs->found)
256 return (const char *)fs->path;
257
258 /* the mount point was already checked for the mount point
259 * but and did not exist, so return NULL to avoid scanning again.
260 * This makes the found and not found paths cost equivalent
261 * in case of multiple calls.
262 */
263 if (fs->checked)
264 return NULL;
265
266 return fs__get_mountpoint(fs);
267}
268
269static const char *mount_overload(struct fs *fs)
270{
271 size_t name_len = strlen(fs->name);
272 /* "PERF_" + name + "_ENVIRONMENT" + '\0' */
273 char upper_name[5 + name_len + 12 + 1];
274
275 snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
276 mem_toupper(upper_name, name_len);
277
278 return getenv(upper_name) ?: *fs->mounts;
279}
280
281static const char *fs__mount(int idx)
282{
283 struct fs *fs = &fs__entries[idx];
284 const char *mountpoint;
285
286 if (fs__mountpoint(idx))
287 return (const char *)fs->path;
288
289 mountpoint = mount_overload(fs);
290
291 if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
292 return NULL;
293
294 return fs__check_mounts(fs) ? fs->path : NULL;
295}
296
297#define FS(name, idx) \
298const char *name##__mountpoint(void) \
299{ \
300 return fs__mountpoint(idx); \
301} \
302 \
303const char *name##__mount(void) \
304{ \
305 return fs__mount(idx); \
306} \
307 \
308bool name##__configured(void) \
309{ \
310 return name##__mountpoint() != NULL; \
311}
312
313FS(sysfs, FS__SYSFS);
314FS(procfs, FS__PROCFS);
315FS(debugfs, FS__DEBUGFS);
316FS(tracefs, FS__TRACEFS);
317FS(hugetlbfs, FS__HUGETLBFS);
318FS(bpf_fs, FS__BPF_FS);
319
320int filename__read_int(const char *filename, int *value)
321{
322 char line[64];
323 int fd = open(filename, O_RDONLY), err = -1;
324
325 if (fd < 0)
326 return -1;
327
328 if (read(fd, line, sizeof(line)) > 0) {
329 *value = atoi(line);
330 err = 0;
331 }
332
333 close(fd);
334 return err;
335}
336
337static int filename__read_ull_base(const char *filename,
338 unsigned long long *value, int base)
339{
340 char line[64];
341 int fd = open(filename, O_RDONLY), err = -1;
342
343 if (fd < 0)
344 return -1;
345
346 if (read(fd, line, sizeof(line)) > 0) {
347 *value = strtoull(line, NULL, base);
348 if (*value != ULLONG_MAX)
349 err = 0;
350 }
351
352 close(fd);
353 return err;
354}
355
356/*
357 * Parses @value out of @filename with strtoull.
358 * By using 16 for base to treat the number as hex.
359 */
360int filename__read_xll(const char *filename, unsigned long long *value)
361{
362 return filename__read_ull_base(filename, value, 16);
363}
364
365/*
366 * Parses @value out of @filename with strtoull.
367 * By using 0 for base, the strtoull detects the
368 * base automatically (see man strtoull).
369 */
370int filename__read_ull(const char *filename, unsigned long long *value)
371{
372 return filename__read_ull_base(filename, value, 0);
373}
374
375#define STRERR_BUFSIZE 128 /* For the buffer size of strerror_r */
376
377int filename__read_str(const char *filename, char **buf, size_t *sizep)
378{
379 size_t size = 0, alloc_size = 0;
380 void *bf = NULL, *nbf;
381 int fd, n, err = 0;
382 char sbuf[STRERR_BUFSIZE];
383
384 fd = open(filename, O_RDONLY);
385 if (fd < 0)
386 return -errno;
387
388 do {
389 if (size == alloc_size) {
390 alloc_size += BUFSIZ;
391 nbf = realloc(bf, alloc_size);
392 if (!nbf) {
393 err = -ENOMEM;
394 break;
395 }
396
397 bf = nbf;
398 }
399
400 n = read(fd, bf + size, alloc_size - size);
401 if (n < 0) {
402 if (size) {
403 pr_warn("read failed %d: %s\n", errno,
404 strerror_r(errno, sbuf, sizeof(sbuf)));
405 err = 0;
406 } else
407 err = -errno;
408
409 break;
410 }
411
412 size += n;
413 } while (n > 0);
414
415 if (!err) {
416 *sizep = size;
417 *buf = bf;
418 } else
419 free(bf);
420
421 close(fd);
422 return err;
423}
424
425int filename__write_int(const char *filename, int value)
426{
427 int fd = open(filename, O_WRONLY), err = -1;
428 char buf[64];
429
430 if (fd < 0)
431 return err;
432
433 sprintf(buf, "%d", value);
434 if (write(fd, buf, sizeof(buf)) == sizeof(buf))
435 err = 0;
436
437 close(fd);
438 return err;
439}
440
441int procfs__read_str(const char *entry, char **buf, size_t *sizep)
442{
443 char path[PATH_MAX];
444 const char *procfs = procfs__mountpoint();
445
446 if (!procfs)
447 return -1;
448
449 snprintf(path, sizeof(path), "%s/%s", procfs, entry);
450
451 return filename__read_str(path, buf, sizep);
452}
453
454static int sysfs__read_ull_base(const char *entry,
455 unsigned long long *value, int base)
456{
457 char path[PATH_MAX];
458 const char *sysfs = sysfs__mountpoint();
459
460 if (!sysfs)
461 return -1;
462
463 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
464
465 return filename__read_ull_base(path, value, base);
466}
467
468int sysfs__read_xll(const char *entry, unsigned long long *value)
469{
470 return sysfs__read_ull_base(entry, value, 16);
471}
472
473int sysfs__read_ull(const char *entry, unsigned long long *value)
474{
475 return sysfs__read_ull_base(entry, value, 0);
476}
477
478int sysfs__read_int(const char *entry, int *value)
479{
480 char path[PATH_MAX];
481 const char *sysfs = sysfs__mountpoint();
482
483 if (!sysfs)
484 return -1;
485
486 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
487
488 return filename__read_int(path, value);
489}
490
491int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
492{
493 char path[PATH_MAX];
494 const char *sysfs = sysfs__mountpoint();
495
496 if (!sysfs)
497 return -1;
498
499 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
500
501 return filename__read_str(path, buf, sizep);
502}
503
504int sysfs__read_bool(const char *entry, bool *value)
505{
506 char *buf;
507 size_t size;
508 int ret;
509
510 ret = sysfs__read_str(entry, &buf, &size);
511 if (ret < 0)
512 return ret;
513
514 switch (buf[0]) {
515 case '1':
516 case 'y':
517 case 'Y':
518 *value = true;
519 break;
520 case '0':
521 case 'n':
522 case 'N':
523 *value = false;
524 break;
525 default:
526 ret = -1;
527 }
528
529 free(buf);
530
531 return ret;
532}
533int sysctl__read_int(const char *sysctl, int *value)
534{
535 char path[PATH_MAX];
536 const char *procfs = procfs__mountpoint();
537
538 if (!procfs)
539 return -1;
540
541 snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
542
543 return filename__read_int(path, value);
544}
545
546int sysfs__write_int(const char *entry, int value)
547{
548 char path[PATH_MAX];
549 const char *sysfs = sysfs__mountpoint();
550
551 if (!sysfs)
552 return -1;
553
554 if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX)
555 return -1;
556
557 return filename__write_int(path, value);
558}