Arnaldo Carvalho de Melo | e2726d9 | 2015-01-22 10:34:22 -0300 | [diff] [blame] | 1 | #define _GNU_SOURCE |
Borislav Petkov | 85c66be | 2013-02-20 16:32:30 +0100 | [diff] [blame] | 2 | #include <errno.h> |
| 3 | #include <stdio.h> |
| 4 | #include <stdlib.h> |
| 5 | #include <string.h> |
Steven Rostedt (Red Hat) | dd6dda2 | 2015-02-02 14:35:06 -0500 | [diff] [blame] | 6 | #include <unistd.h> |
Borislav Petkov | 85c66be | 2013-02-20 16:32:30 +0100 | [diff] [blame] | 7 | #include <stdbool.h> |
| 8 | #include <sys/vfs.h> |
Steven Rostedt (Red Hat) | dd6dda2 | 2015-02-02 14:35:06 -0500 | [diff] [blame] | 9 | #include <sys/types.h> |
| 10 | #include <sys/stat.h> |
Arnaldo Carvalho de Melo | c168fbf | 2011-11-16 12:55:59 -0200 | [diff] [blame] | 11 | #include <sys/mount.h> |
Borislav Petkov | 85c66be | 2013-02-20 16:32:30 +0100 | [diff] [blame] | 12 | #include <linux/kernel.h> |
| 13 | |
| 14 | #include "debugfs.h" |
Arnaldo Carvalho de Melo | c168fbf | 2011-11-16 12:55:59 -0200 | [diff] [blame] | 15 | |
Steven Rostedt (Red Hat) | a9edf60 | 2015-02-02 14:35:05 -0500 | [diff] [blame] | 16 | #ifndef DEBUGFS_DEFAULT_PATH |
| 17 | #define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug" |
| 18 | #endif |
| 19 | |
| 20 | char debugfs_mountpoint[PATH_MAX + 1] = DEBUGFS_DEFAULT_PATH; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 21 | |
Borislav Petkov | 85c66be | 2013-02-20 16:32:30 +0100 | [diff] [blame] | 22 | static const char * const debugfs_known_mountpoints[] = { |
Steven Rostedt (Red Hat) | a9edf60 | 2015-02-02 14:35:05 -0500 | [diff] [blame] | 23 | DEBUGFS_DEFAULT_PATH, |
Xia Kaixu | 603940b | 2014-04-26 15:55:12 +0800 | [diff] [blame] | 24 | "/debug", |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 25 | 0, |
| 26 | }; |
| 27 | |
Borislav Petkov | fed1208 | 2013-02-20 16:32:27 +0100 | [diff] [blame] | 28 | static bool debugfs_found; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 29 | |
Steven Rostedt (Red Hat) | dd6dda2 | 2015-02-02 14:35:06 -0500 | [diff] [blame] | 30 | bool debugfs_configured(void) |
| 31 | { |
| 32 | return debugfs_find_mountpoint() != NULL; |
| 33 | } |
| 34 | |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 35 | /* find the path to the mounted debugfs */ |
| 36 | const char *debugfs_find_mountpoint(void) |
| 37 | { |
Steven Rostedt (Red Hat) | cde164a | 2015-02-02 14:35:03 -0500 | [diff] [blame] | 38 | const char *ret; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 39 | |
| 40 | if (debugfs_found) |
Borislav Petkov | 85c66be | 2013-02-20 16:32:30 +0100 | [diff] [blame] | 41 | return (const char *)debugfs_mountpoint; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 42 | |
Steven Rostedt (Red Hat) | cde164a | 2015-02-02 14:35:03 -0500 | [diff] [blame] | 43 | ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC, |
| 44 | debugfs_mountpoint, PATH_MAX + 1, |
| 45 | debugfs_known_mountpoints); |
| 46 | if (ret) |
| 47 | debugfs_found = true; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 48 | |
Steven Rostedt (Red Hat) | cde164a | 2015-02-02 14:35:03 -0500 | [diff] [blame] | 49 | return ret; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 50 | } |
| 51 | |
Xiao Guangrong | 29c52aa | 2009-12-28 16:47:12 +0800 | [diff] [blame] | 52 | /* mount the debugfs somewhere if it's not mounted */ |
Xiao Guangrong | 29c52aa | 2009-12-28 16:47:12 +0800 | [diff] [blame] | 53 | char *debugfs_mount(const char *mountpoint) |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 54 | { |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 55 | /* see if it's already mounted */ |
Borislav Petkov | fed1208 | 2013-02-20 16:32:27 +0100 | [diff] [blame] | 56 | if (debugfs_find_mountpoint()) |
Arnaldo Carvalho de Melo | ebf294b | 2011-11-16 14:03:07 -0200 | [diff] [blame] | 57 | goto out; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 58 | |
| 59 | /* if not mounted and no argument */ |
| 60 | if (mountpoint == NULL) { |
| 61 | /* see if environment variable set */ |
| 62 | mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT); |
| 63 | /* if no environment variable, use default */ |
| 64 | if (mountpoint == NULL) |
Steven Rostedt (Red Hat) | a9edf60 | 2015-02-02 14:35:05 -0500 | [diff] [blame] | 65 | mountpoint = DEBUGFS_DEFAULT_PATH; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 66 | } |
| 67 | |
Xiao Guangrong | 29c52aa | 2009-12-28 16:47:12 +0800 | [diff] [blame] | 68 | if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0) |
| 69 | return NULL; |
| 70 | |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 71 | /* save the mountpoint */ |
Borislav Petkov | fed1208 | 2013-02-20 16:32:27 +0100 | [diff] [blame] | 72 | debugfs_found = true; |
Arnaldo Carvalho de Melo | ebf294b | 2011-11-16 14:03:07 -0200 | [diff] [blame] | 73 | strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint)); |
| 74 | out: |
Xiao Guangrong | 29c52aa | 2009-12-28 16:47:12 +0800 | [diff] [blame] | 75 | return debugfs_mountpoint; |
Clark Williams | afe61f6 | 2009-11-08 09:01:37 -0600 | [diff] [blame] | 76 | } |
Arnaldo Carvalho de Melo | e2726d9 | 2015-01-22 10:34:22 -0300 | [diff] [blame] | 77 | |
Arnaldo Carvalho de Melo | 801c67b | 2015-01-22 10:52:55 -0300 | [diff] [blame] | 78 | int debugfs__strerror_open(int err, char *buf, size_t size, const char *filename) |
Arnaldo Carvalho de Melo | e2726d9 | 2015-01-22 10:34:22 -0300 | [diff] [blame] | 79 | { |
| 80 | char sbuf[128]; |
| 81 | |
| 82 | switch (err) { |
| 83 | case ENOENT: |
Arnaldo Carvalho de Melo | f816b3c | 2015-01-22 16:35:42 -0300 | [diff] [blame] | 84 | if (debugfs_found) { |
| 85 | snprintf(buf, size, |
| 86 | "Error:\tFile %s/%s not found.\n" |
| 87 | "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n", |
| 88 | debugfs_mountpoint, filename); |
| 89 | break; |
| 90 | } |
Arnaldo Carvalho de Melo | e2726d9 | 2015-01-22 10:34:22 -0300 | [diff] [blame] | 91 | snprintf(buf, size, "%s", |
| 92 | "Error:\tUnable to find debugfs\n" |
| 93 | "Hint:\tWas your kernel compiled with debugfs support?\n" |
| 94 | "Hint:\tIs the debugfs filesystem mounted?\n" |
| 95 | "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'"); |
| 96 | break; |
| 97 | case EACCES: |
| 98 | snprintf(buf, size, |
Arnaldo Carvalho de Melo | 801c67b | 2015-01-22 10:52:55 -0300 | [diff] [blame] | 99 | "Error:\tNo permissions to read %s/%s\n" |
Arnaldo Carvalho de Melo | e2726d9 | 2015-01-22 10:34:22 -0300 | [diff] [blame] | 100 | "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n", |
Arnaldo Carvalho de Melo | 801c67b | 2015-01-22 10:52:55 -0300 | [diff] [blame] | 101 | debugfs_mountpoint, filename, debugfs_mountpoint); |
Arnaldo Carvalho de Melo | e2726d9 | 2015-01-22 10:34:22 -0300 | [diff] [blame] | 102 | break; |
| 103 | default: |
| 104 | snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf))); |
| 105 | break; |
| 106 | } |
| 107 | |
| 108 | return 0; |
| 109 | } |
Arnaldo Carvalho de Melo | 2cc990b | 2015-01-22 11:13:43 -0300 | [diff] [blame] | 110 | |
| 111 | int debugfs__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name) |
| 112 | { |
| 113 | char path[PATH_MAX]; |
| 114 | |
| 115 | snprintf(path, PATH_MAX, "tracing/events/%s/%s", sys, name ?: "*"); |
| 116 | |
| 117 | return debugfs__strerror_open(err, buf, size, path); |
| 118 | } |