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 static const char * const sysfs__fs_known_mountpoints[] = {
42 static const char * const procfs__known_mountpoints[] = {
47 #ifndef DEBUGFS_DEFAULT_PATH
48 #define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
51 static const char * const debugfs__known_mountpoints[] = {
58 #ifndef TRACEFS_DEFAULT_PATH
59 #define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
62 static const char * const tracefs__known_mountpoints[] = {
64 "/sys/kernel/debug/tracing",
72 const char * const *mounts;
86 #define TRACEFS_MAGIC 0x74726163
89 static struct fs fs__entries[] = {
92 .mounts = sysfs__fs_known_mountpoints,
97 .mounts = procfs__known_mountpoints,
98 .magic = PROC_SUPER_MAGIC,
102 .mounts = debugfs__known_mountpoints,
103 .magic = DEBUGFS_MAGIC,
107 .mounts = tracefs__known_mountpoints,
108 .magic = TRACEFS_MAGIC,
112 static bool fs__read_mounts(struct fs *fs)
118 fp = fopen("/proc/mounts", "r");
123 fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
124 fs->path, type) == 2) {
126 if (strcmp(type, fs->name) == 0)
131 return fs->found = found;
134 static int fs__valid_mount(const char *fs, long magic)
138 if (statfs(fs, &st_fs) < 0)
140 else if ((long)st_fs.f_type != magic)
146 static bool fs__check_mounts(struct fs *fs)
148 const char * const *ptr;
152 if (fs__valid_mount(*ptr, fs->magic) == 0) {
154 strcpy(fs->path, *ptr);
163 static void mem_toupper(char *f, size_t len)
173 * Check for "NAME_PATH" environment variable to override fs location (for
174 * testing). This matches the recommendation in Documentation/sysfs-rules.txt
177 static bool fs__env_override(struct fs *fs)
180 size_t name_len = strlen(fs->name);
181 /* name + "_PATH" + '\0' */
182 char upper_name[name_len + 5 + 1];
183 memcpy(upper_name, fs->name, name_len);
184 mem_toupper(upper_name, name_len);
185 strcpy(&upper_name[name_len], "_PATH");
187 override_path = getenv(upper_name);
192 strncpy(fs->path, override_path, sizeof(fs->path));
196 static const char *fs__get_mountpoint(struct fs *fs)
198 if (fs__env_override(fs))
201 if (fs__check_mounts(fs))
204 if (fs__read_mounts(fs))
210 static const char *fs__mountpoint(int idx)
212 struct fs *fs = &fs__entries[idx];
215 return (const char *)fs->path;
217 return fs__get_mountpoint(fs);
220 static const char *mount_overload(struct fs *fs)
222 size_t name_len = strlen(fs->name);
223 /* "PERF_" + name + "_ENVIRONMENT" + '\0' */
224 char upper_name[5 + name_len + 12 + 1];
226 snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
227 mem_toupper(upper_name, name_len);
229 return getenv(upper_name) ?: *fs->mounts;
232 static const char *fs__mount(int idx)
234 struct fs *fs = &fs__entries[idx];
235 const char *mountpoint;
237 if (fs__mountpoint(idx))
238 return (const char *)fs->path;
240 mountpoint = mount_overload(fs);
242 if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
245 return fs__check_mounts(fs) ? fs->path : NULL;
248 #define FS(name, idx) \
249 const char *name##__mountpoint(void) \
251 return fs__mountpoint(idx); \
254 const char *name##__mount(void) \
256 return fs__mount(idx); \
259 bool name##__configured(void) \
261 return name##__mountpoint() != NULL; \
264 FS(sysfs, FS__SYSFS);
265 FS(procfs, FS__PROCFS);
266 FS(debugfs, FS__DEBUGFS);
267 FS(tracefs, FS__TRACEFS);
269 int filename__read_int(const char *filename, int *value)
272 int fd = open(filename, O_RDONLY), err = -1;
277 if (read(fd, line, sizeof(line)) > 0) {
286 int filename__read_ull(const char *filename, unsigned long long *value)
289 int fd = open(filename, O_RDONLY), err = -1;
294 if (read(fd, line, sizeof(line)) > 0) {
295 *value = strtoull(line, NULL, 10);
296 if (*value != ULLONG_MAX)
304 #define STRERR_BUFSIZE 128 /* For the buffer size of strerror_r */
306 int filename__read_str(const char *filename, char **buf, size_t *sizep)
308 size_t size = 0, alloc_size = 0;
309 void *bf = NULL, *nbf;
311 char sbuf[STRERR_BUFSIZE];
313 fd = open(filename, O_RDONLY);
318 if (size == alloc_size) {
319 alloc_size += BUFSIZ;
320 nbf = realloc(bf, alloc_size);
329 n = read(fd, bf + size, alloc_size - size);
332 pr_warning("read failed %d: %s\n", errno,
333 strerror_r(errno, sbuf, sizeof(sbuf)));
354 int procfs__read_str(const char *entry, char **buf, size_t *sizep)
357 const char *procfs = procfs__mountpoint();
362 snprintf(path, sizeof(path), "%s/%s", procfs, entry);
364 return filename__read_str(path, buf, sizep);
367 int sysfs__read_ull(const char *entry, unsigned long long *value)
370 const char *sysfs = sysfs__mountpoint();
375 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
377 return filename__read_ull(path, value);
380 int sysfs__read_int(const char *entry, int *value)
383 const char *sysfs = sysfs__mountpoint();
388 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
390 return filename__read_int(path, value);
393 int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
396 const char *sysfs = sysfs__mountpoint();
401 snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
403 return filename__read_str(path, buf, sizep);
406 int sysctl__read_int(const char *sysctl, int *value)
409 const char *procfs = procfs__mountpoint();
414 snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
416 return filename__read_int(path, value);