This source file includes following definitions.
- fs__read_mounts
- fs__valid_mount
- fs__check_mounts
- mem_toupper
- fs__env_override
- fs__get_mountpoint
- fs__mountpoint
- mount_overload
- fs__mount
- filename__read_int
- filename__read_ull_base
- filename__read_xll
- filename__read_ull
- filename__read_str
- filename__write_int
- procfs__read_str
- sysfs__read_ull_base
- sysfs__read_xll
- sysfs__read_ull
- sysfs__read_int
- sysfs__read_str
- sysfs__read_bool
- sysctl__read_int
- sysfs__write_int
1
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
46 static const char * const sysfs__fs_known_mountpoints[] = {
47 "/sys",
48 0,
49 };
50
51 static 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
60 static 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
71 static const char * const tracefs__known_mountpoints[] = {
72 TRACEFS_DEFAULT_PATH,
73 "/sys/kernel/debug/tracing",
74 "/tracing",
75 "/trace",
76 0,
77 };
78
79 static const char * const hugetlbfs__known_mountpoints[] = {
80 0,
81 };
82
83 static const char * const bpf_fs__known_mountpoints[] = {
84 "/sys/fs/bpf",
85 0,
86 };
87
88 struct fs {
89 const char *name;
90 const char * const *mounts;
91 char path[PATH_MAX];
92 bool found;
93 long magic;
94 };
95
96 enum {
97 FS__SYSFS = 0,
98 FS__PROCFS = 1,
99 FS__DEBUGFS = 2,
100 FS__TRACEFS = 3,
101 FS__HUGETLBFS = 4,
102 FS__BPF_FS = 5,
103 };
104
105 #ifndef TRACEFS_MAGIC
106 #define TRACEFS_MAGIC 0x74726163
107 #endif
108
109 static struct fs fs__entries[] = {
110 [FS__SYSFS] = {
111 .name = "sysfs",
112 .mounts = sysfs__fs_known_mountpoints,
113 .magic = SYSFS_MAGIC,
114 },
115 [FS__PROCFS] = {
116 .name = "proc",
117 .mounts = procfs__known_mountpoints,
118 .magic = PROC_SUPER_MAGIC,
119 },
120 [FS__DEBUGFS] = {
121 .name = "debugfs",
122 .mounts = debugfs__known_mountpoints,
123 .magic = DEBUGFS_MAGIC,
124 },
125 [FS__TRACEFS] = {
126 .name = "tracefs",
127 .mounts = tracefs__known_mountpoints,
128 .magic = TRACEFS_MAGIC,
129 },
130 [FS__HUGETLBFS] = {
131 .name = "hugetlbfs",
132 .mounts = hugetlbfs__known_mountpoints,
133 .magic = HUGETLBFS_MAGIC,
134 },
135 [FS__BPF_FS] = {
136 .name = "bpf",
137 .mounts = bpf_fs__known_mountpoints,
138 .magic = BPF_FS_MAGIC,
139 },
140 };
141
142 static bool fs__read_mounts(struct fs *fs)
143 {
144 bool found = false;
145 char type[100];
146 FILE *fp;
147
148 fp = fopen("/proc/mounts", "r");
149 if (fp == NULL)
150 return NULL;
151
152 while (!found &&
153 fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
154 fs->path, type) == 2) {
155
156 if (strcmp(type, fs->name) == 0)
157 found = true;
158 }
159
160 fclose(fp);
161 return fs->found = found;
162 }
163
164 static int fs__valid_mount(const char *fs, long magic)
165 {
166 struct statfs st_fs;
167
168 if (statfs(fs, &st_fs) < 0)
169 return -ENOENT;
170 else if ((long)st_fs.f_type != magic)
171 return -ENOENT;
172
173 return 0;
174 }
175
176 static bool fs__check_mounts(struct fs *fs)
177 {
178 const char * const *ptr;
179
180 ptr = fs->mounts;
181 while (*ptr) {
182 if (fs__valid_mount(*ptr, fs->magic) == 0) {
183 fs->found = true;
184 strcpy(fs->path, *ptr);
185 return true;
186 }
187 ptr++;
188 }
189
190 return false;
191 }
192
193 static void mem_toupper(char *f, size_t len)
194 {
195 while (len) {
196 *f = toupper(*f);
197 f++;
198 len--;
199 }
200 }
201
202
203
204
205
206
207 static bool fs__env_override(struct fs *fs)
208 {
209 char *override_path;
210 size_t name_len = strlen(fs->name);
211
212 char upper_name[name_len + 5 + 1];
213
214 memcpy(upper_name, fs->name, name_len);
215 mem_toupper(upper_name, name_len);
216 strcpy(&upper_name[name_len], "_PATH");
217
218 override_path = getenv(upper_name);
219 if (!override_path)
220 return false;
221
222 fs->found = true;
223 strncpy(fs->path, override_path, sizeof(fs->path) - 1);
224 fs->path[sizeof(fs->path) - 1] = '\0';
225 return true;
226 }
227
228 static const char *fs__get_mountpoint(struct fs *fs)
229 {
230 if (fs__env_override(fs))
231 return fs->path;
232
233 if (fs__check_mounts(fs))
234 return fs->path;
235
236 if (fs__read_mounts(fs))
237 return fs->path;
238
239 return NULL;
240 }
241
242 static const char *fs__mountpoint(int idx)
243 {
244 struct fs *fs = &fs__entries[idx];
245
246 if (fs->found)
247 return (const char *)fs->path;
248
249 return fs__get_mountpoint(fs);
250 }
251
252 static const char *mount_overload(struct fs *fs)
253 {
254 size_t name_len = strlen(fs->name);
255
256 char upper_name[5 + name_len + 12 + 1];
257
258 snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
259 mem_toupper(upper_name, name_len);
260
261 return getenv(upper_name) ?: *fs->mounts;
262 }
263
264 static const char *fs__mount(int idx)
265 {
266 struct fs *fs = &fs__entries[idx];
267 const char *mountpoint;
268
269 if (fs__mountpoint(idx))
270 return (const char *)fs->path;
271
272 mountpoint = mount_overload(fs);
273
274 if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
275 return NULL;
276
277 return fs__check_mounts(fs) ? fs->path : NULL;
278 }
279
280 #define FS(name, idx) \
281 const char *name##__mountpoint(void) \
282 { \
283 return fs__mountpoint(idx); \
284 } \
285 \
286 const char *name##__mount(void) \
287 { \
288 return fs__mount(idx); \
289 } \
290 \
291 bool name##__configured(void) \
292 { \
293 return name##__mountpoint() != NULL; \
294 }
295
296 FS(sysfs, FS__SYSFS);
297 FS(procfs, FS__PROCFS);
298 FS(debugfs, FS__DEBUGFS);
299 FS(tracefs, FS__TRACEFS);
300 FS(hugetlbfs, FS__HUGETLBFS);
301 FS(bpf_fs, FS__BPF_FS);
302
303 int filename__read_int(const char *filename, int *value)
304 {
305 char line[64];
306 int fd = open(filename, O_RDONLY), err = -1;
307
308 if (fd < 0)
309 return -1;
310
311 if (read(fd, line, sizeof(line)) > 0) {
312 *value = atoi(line);
313 err = 0;
314 }
315
316 close(fd);
317 return err;
318 }
319
320 static int filename__read_ull_base(const char *filename,
321 unsigned long long *value, int base)
322 {
323 char line[64];
324 int fd = open(filename, O_RDONLY), err = -1;
325
326 if (fd < 0)
327 return -1;
328
329 if (read(fd, line, sizeof(line)) > 0) {
330 *value = strtoull(line, NULL, base);
331 if (*value != ULLONG_MAX)
332 err = 0;
333 }
334
335 close(fd);
336 return err;
337 }
338
339
340
341
342
343 int filename__read_xll(const char *filename, unsigned long long *value)
344 {
345 return filename__read_ull_base(filename, value, 16);
346 }
347
348
349
350
351
352
353 int filename__read_ull(const char *filename, unsigned long long *value)
354 {
355 return filename__read_ull_base(filename, value, 0);
356 }
357
358 #define STRERR_BUFSIZE 128
359
360 int filename__read_str(const char *filename, char **buf, size_t *sizep)
361 {
362 size_t size = 0, alloc_size = 0;
363 void *bf = NULL, *nbf;
364 int fd, n, err = 0;
365 char sbuf[STRERR_BUFSIZE];
366
367 fd = open(filename, O_RDONLY);
368 if (fd < 0)
369 return -errno;
370
371 do {
372 if (size == alloc_size) {
373 alloc_size += BUFSIZ;
374 nbf = realloc(bf, alloc_size);
375 if (!nbf) {
376 err = -ENOMEM;
377 break;
378 }
379
380 bf = nbf;
381 }
382
383 n = read(fd, bf + size, alloc_size - size);
384 if (n < 0) {
385 if (size) {
386 pr_warning("read failed %d: %s\n", errno,
387 strerror_r(errno, sbuf, sizeof(sbuf)));
388 err = 0;
389 } else
390 err = -errno;
391
392 break;
393 }
394
395 size += n;
396 } while (n > 0);
397
398 if (!err) {
399 *sizep = size;
400 *buf = bf;
401 } else
402 free(bf);
403
404 close(fd);
405 return err;
406 }
407
408 int filename__write_int(const char *filename, int value)
409 {
410 int fd = open(filename, O_WRONLY), err = -1;
411 char buf[64];
412
413 if (fd < 0)
414 return err;
415
416 sprintf(buf, "%d", value);
417 if (write(fd, buf, sizeof(buf)) == sizeof(buf))
418 err = 0;
419
420 close(fd);
421 return err;
422 }
423
424 int procfs__read_str(const char *entry, char **buf, size_t *sizep)
425 {
426 char path[PATH_MAX];
427 const char *procfs = procfs__mountpoint();
428
429 if (!procfs)
430 return -1;
431
432 snprintf(path, sizeof(path), "%s/%s", procfs, entry);
433
434 return filename__read_str(path, buf, sizep);
435 }
436
437 static int sysfs__read_ull_base(const char *entry,
438 unsigned long long *value, int base)
439 {
440 char path[PATH_MAX];
441 const char *sysfs = sysfs__mountpoint();
442
443 if (!sysfs)
444 return -1;
445
446 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
447
448 return filename__read_ull_base(path, value, base);
449 }
450
451 int sysfs__read_xll(const char *entry, unsigned long long *value)
452 {
453 return sysfs__read_ull_base(entry, value, 16);
454 }
455
456 int sysfs__read_ull(const char *entry, unsigned long long *value)
457 {
458 return sysfs__read_ull_base(entry, value, 0);
459 }
460
461 int sysfs__read_int(const char *entry, int *value)
462 {
463 char path[PATH_MAX];
464 const char *sysfs = sysfs__mountpoint();
465
466 if (!sysfs)
467 return -1;
468
469 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
470
471 return filename__read_int(path, value);
472 }
473
474 int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
475 {
476 char path[PATH_MAX];
477 const char *sysfs = sysfs__mountpoint();
478
479 if (!sysfs)
480 return -1;
481
482 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
483
484 return filename__read_str(path, buf, sizep);
485 }
486
487 int sysfs__read_bool(const char *entry, bool *value)
488 {
489 char *buf;
490 size_t size;
491 int ret;
492
493 ret = sysfs__read_str(entry, &buf, &size);
494 if (ret < 0)
495 return ret;
496
497 switch (buf[0]) {
498 case '1':
499 case 'y':
500 case 'Y':
501 *value = true;
502 break;
503 case '0':
504 case 'n':
505 case 'N':
506 *value = false;
507 break;
508 default:
509 ret = -1;
510 }
511
512 free(buf);
513
514 return ret;
515 }
516 int sysctl__read_int(const char *sysctl, int *value)
517 {
518 char path[PATH_MAX];
519 const char *procfs = procfs__mountpoint();
520
521 if (!procfs)
522 return -1;
523
524 snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
525
526 return filename__read_int(path, value);
527 }
528
529 int sysfs__write_int(const char *entry, int value)
530 {
531 char path[PATH_MAX];
532 const char *sysfs = sysfs__mountpoint();
533
534 if (!sysfs)
535 return -1;
536
537 if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX)
538 return -1;
539
540 return filename__write_int(path, value);
541 }