| #define _GNU_SOURCE |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <stdbool.h> |
| #include <sys/vfs.h> |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <sys/mount.h> |
| #include <linux/kernel.h> |
| |
| #include "debugfs.h" |
| #include "tracefs.h" |
| |
| #ifndef DEBUGFS_DEFAULT_PATH |
| #define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug" |
| #endif |
| |
| char debugfs_mountpoint[PATH_MAX + 1] = DEBUGFS_DEFAULT_PATH; |
| |
| static const char * const debugfs_known_mountpoints[] = { |
| DEBUGFS_DEFAULT_PATH, |
| "/debug", |
| 0, |
| }; |
| |
| static bool debugfs_found; |
| |
| bool debugfs_configured(void) |
| { |
| return debugfs_find_mountpoint() != NULL; |
| } |
| |
| /* find the path to the mounted debugfs */ |
| const char *debugfs_find_mountpoint(void) |
| { |
| const char *ret; |
| |
| if (debugfs_found) |
| return (const char *)debugfs_mountpoint; |
| |
| ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC, |
| debugfs_mountpoint, PATH_MAX + 1, |
| debugfs_known_mountpoints); |
| if (ret) |
| debugfs_found = true; |
| |
| return ret; |
| } |
| |
| /* mount the debugfs somewhere if it's not mounted */ |
| char *debugfs_mount(const char *mountpoint) |
| { |
| /* see if it's already mounted */ |
| if (debugfs_find_mountpoint()) |
| goto out; |
| |
| /* if not mounted and no argument */ |
| if (mountpoint == NULL) { |
| /* see if environment variable set */ |
| mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT); |
| /* if no environment variable, use default */ |
| if (mountpoint == NULL) |
| mountpoint = DEBUGFS_DEFAULT_PATH; |
| } |
| |
| if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0) |
| return NULL; |
| |
| /* save the mountpoint */ |
| debugfs_found = true; |
| strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint)); |
| out: |
| return debugfs_mountpoint; |
| } |
| |
| int debugfs__strerror_open(int err, char *buf, size_t size, const char *filename) |
| { |
| char sbuf[128]; |
| |
| switch (err) { |
| case ENOENT: |
| if (debugfs_found) { |
| snprintf(buf, size, |
| "Error:\tFile %s/%s not found.\n" |
| "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n", |
| debugfs_mountpoint, filename); |
| break; |
| } |
| snprintf(buf, size, "%s", |
| "Error:\tUnable to find debugfs\n" |
| "Hint:\tWas your kernel compiled with debugfs support?\n" |
| "Hint:\tIs the debugfs filesystem mounted?\n" |
| "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'"); |
| break; |
| case EACCES: { |
| const char *mountpoint = debugfs_mountpoint; |
| |
| if (!access(debugfs_mountpoint, R_OK) && strncmp(filename, "tracing/", 8) == 0) { |
| const char *tracefs_mntpoint = tracefs_find_mountpoint(); |
| |
| if (tracefs_mntpoint) |
| mountpoint = tracefs_mntpoint; |
| } |
| |
| snprintf(buf, size, |
| "Error:\tNo permissions to read %s/%s\n" |
| "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n", |
| debugfs_mountpoint, filename, mountpoint); |
| } |
| break; |
| default: |
| snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf))); |
| break; |
| } |
| |
| return 0; |
| } |
| |
| int debugfs__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name) |
| { |
| char path[PATH_MAX]; |
| |
| snprintf(path, PATH_MAX, "tracing/events/%s/%s", sys, name ?: "*"); |
| |
| return debugfs__strerror_open(err, buf, size, path); |
| } |