13 #include <sys/mount.h>
16 #include "debug-internal.h"
19 #define STR(x) _STR(x)
22 #define SYSFS_MAGIC 0x62656572
25 #ifndef PROC_SUPER_MAGIC
26 #define PROC_SUPER_MAGIC 0x9fa0
30 #define DEBUGFS_MAGIC 0x64626720
34 #define TRACEFS_MAGIC 0x74726163
37 #ifndef HUGETLBFS_MAGIC
38 #define HUGETLBFS_MAGIC 0x958458f6
42 #define BPF_FS_MAGIC 0xcafe4a11
45 static const char * const sysfs__fs_known_mountpoints[] = {
50 static const char * const procfs__known_mountpoints[] = {
55 #ifndef DEBUGFS_DEFAULT_PATH
56 #define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
59 static const char * const debugfs__known_mountpoints[] = {
66 #ifndef TRACEFS_DEFAULT_PATH
67 #define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
70 static const char * const tracefs__known_mountpoints[] = {
72 "/sys/kernel/debug/tracing",
78 static const char * const hugetlbfs__known_mountpoints[] = {
82 static const char * const bpf_fs__known_mountpoints[] = {
89 const char * const *mounts;
104 #ifndef TRACEFS_MAGIC
105 #define TRACEFS_MAGIC 0x74726163
108 static struct fs fs__entries[] = {
111 .mounts = sysfs__fs_known_mountpoints,
112 .magic = SYSFS_MAGIC,
116 .mounts = procfs__known_mountpoints,
117 .magic = PROC_SUPER_MAGIC,
121 .mounts = debugfs__known_mountpoints,
122 .magic = DEBUGFS_MAGIC,
126 .mounts = tracefs__known_mountpoints,
127 .magic = TRACEFS_MAGIC,
131 .mounts = hugetlbfs__known_mountpoints,
132 .magic = HUGETLBFS_MAGIC,
136 .mounts = bpf_fs__known_mountpoints,
137 .magic = BPF_FS_MAGIC,
141 static bool fs__read_mounts(struct fs *fs)
147 fp = fopen("/proc/mounts", "r");
152 fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
153 fs->path, type) == 2) {
155 if (strcmp(type, fs->name) == 0)
160 return fs->found = found;
163 static int fs__valid_mount(const char *fs, long magic)
167 if (statfs(fs, &st_fs) < 0)
169 else if ((long)st_fs.f_type != magic)
175 static bool fs__check_mounts(struct fs *fs)
177 const char * const *ptr;
181 if (fs__valid_mount(*ptr, fs->magic) == 0) {
183 strcpy(fs->path, *ptr);
192 static void mem_toupper(char *f, size_t len)
202 * Check for "NAME_PATH" environment variable to override fs location (for
203 * testing). This matches the recommendation in Documentation/sysfs-rules.txt
206 static bool fs__env_override(struct fs *fs)
209 size_t name_len = strlen(fs->name);
210 /* name + "_PATH" + '\0' */
211 char upper_name[name_len + 5 + 1];
212 memcpy(upper_name, fs->name, name_len);
213 mem_toupper(upper_name, name_len);
214 strcpy(&upper_name[name_len], "_PATH");
216 override_path = getenv(upper_name);
221 strncpy(fs->path, override_path, sizeof(fs->path));
225 static const char *fs__get_mountpoint(struct fs *fs)
227 if (fs__env_override(fs))
230 if (fs__check_mounts(fs))
233 if (fs__read_mounts(fs))
239 static const char *fs__mountpoint(int idx)
241 struct fs *fs = &fs__entries[idx];
244 return (const char *)fs->path;
246 return fs__get_mountpoint(fs);
249 static const char *mount_overload(struct fs *fs)
251 size_t name_len = strlen(fs->name);
252 /* "PERF_" + name + "_ENVIRONMENT" + '\0' */
253 char upper_name[5 + name_len + 12 + 1];
255 snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
256 mem_toupper(upper_name, name_len);
258 return getenv(upper_name) ?: *fs->mounts;
261 static const char *fs__mount(int idx)
263 struct fs *fs = &fs__entries[idx];
264 const char *mountpoint;
266 if (fs__mountpoint(idx))
267 return (const char *)fs->path;
269 mountpoint = mount_overload(fs);
271 if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
274 return fs__check_mounts(fs) ? fs->path : NULL;
277 #define FS(name, idx) \
278 const char *name##__mountpoint(void) \
280 return fs__mountpoint(idx); \
283 const char *name##__mount(void) \
285 return fs__mount(idx); \
288 bool name##__configured(void) \
290 return name##__mountpoint() != NULL; \
293 FS(sysfs, FS__SYSFS);
294 FS(procfs, FS__PROCFS);
295 FS(debugfs, FS__DEBUGFS);
296 FS(tracefs, FS__TRACEFS);
297 FS(hugetlbfs, FS__HUGETLBFS);
298 FS(bpf_fs, FS__BPF_FS);
300 int filename__read_int(const char *filename, int *value)
303 int fd = open(filename, O_RDONLY), err = -1;
308 if (read(fd, line, sizeof(line)) > 0) {
318 * Parses @value out of @filename with strtoull.
319 * By using 0 for base, the strtoull detects the
320 * base automatically (see man strtoull).
322 int filename__read_ull(const char *filename, unsigned long long *value)
325 int fd = open(filename, O_RDONLY), err = -1;
330 if (read(fd, line, sizeof(line)) > 0) {
331 *value = strtoull(line, NULL, 0);
332 if (*value != ULLONG_MAX)
340 #define STRERR_BUFSIZE 128 /* For the buffer size of strerror_r */
342 int filename__read_str(const char *filename, char **buf, size_t *sizep)
344 size_t size = 0, alloc_size = 0;
345 void *bf = NULL, *nbf;
347 char sbuf[STRERR_BUFSIZE];
349 fd = open(filename, O_RDONLY);
354 if (size == alloc_size) {
355 alloc_size += BUFSIZ;
356 nbf = realloc(bf, alloc_size);
365 n = read(fd, bf + size, alloc_size - size);
368 pr_warning("read failed %d: %s\n", errno,
369 strerror_r(errno, sbuf, sizeof(sbuf)));
390 int procfs__read_str(const char *entry, char **buf, size_t *sizep)
393 const char *procfs = procfs__mountpoint();
398 snprintf(path, sizeof(path), "%s/%s", procfs, entry);
400 return filename__read_str(path, buf, sizep);
403 int sysfs__read_ull(const char *entry, unsigned long long *value)
406 const char *sysfs = sysfs__mountpoint();
411 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
413 return filename__read_ull(path, value);
416 int sysfs__read_int(const char *entry, int *value)
419 const char *sysfs = sysfs__mountpoint();
424 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
426 return filename__read_int(path, value);
429 int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
432 const char *sysfs = sysfs__mountpoint();
437 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
439 return filename__read_str(path, buf, sizep);
442 int sysctl__read_int(const char *sysctl, int *value)
445 const char *procfs = procfs__mountpoint();
450 snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
452 return filename__read_int(path, value);