1 #ifndef _GNU_SOURCE 2 # define _GNU_SOURCE 3 #endif 4 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <string.h> 8 #include <errno.h> 9 #include <unistd.h> 10 #include "fs.h" 11 12 #include "tracing_path.h" 13 14 15 char tracing_mnt[PATH_MAX + 1] = "/sys/kernel/debug"; 16 char tracing_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing"; 17 char tracing_events_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing/events"; 18 19 20 static void __tracing_path_set(const char *tracing, const char *mountpoint) 21 { 22 snprintf(tracing_mnt, sizeof(tracing_mnt), "%s", mountpoint); 23 snprintf(tracing_path, sizeof(tracing_path), "%s/%s", 24 mountpoint, tracing); 25 snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s%s", 26 mountpoint, tracing, "events"); 27 } 28 29 static const char *tracing_path_tracefs_mount(void) 30 { 31 const char *mnt; 32 33 mnt = tracefs__mount(); 34 if (!mnt) 35 return NULL; 36 37 __tracing_path_set("", mnt); 38 39 return mnt; 40 } 41 42 static const char *tracing_path_debugfs_mount(void) 43 { 44 const char *mnt; 45 46 mnt = debugfs__mount(); 47 if (!mnt) 48 return NULL; 49 50 __tracing_path_set("tracing/", mnt); 51 52 return mnt; 53 } 54 55 const char *tracing_path_mount(void) 56 { 57 const char *mnt; 58 59 mnt = tracing_path_tracefs_mount(); 60 if (mnt) 61 return mnt; 62 63 mnt = tracing_path_debugfs_mount(); 64 65 return mnt; 66 } 67 68 void tracing_path_set(const char *mntpt) 69 { 70 __tracing_path_set("tracing/", mntpt); 71 } 72 73 char *get_tracing_file(const char *name) 74 { 75 char *file; 76 77 if (asprintf(&file, "%s/%s", tracing_path, name) < 0) 78 return NULL; 79 80 return file; 81 } 82 83 void put_tracing_file(char *file) 84 { 85 free(file); 86 } 87 88 static int strerror_open(int err, char *buf, size_t size, const char *filename) 89 { 90 char sbuf[128]; 91 92 switch (err) { 93 case ENOENT: 94 /* 95 * We will get here if we can't find the tracepoint, but one of 96 * debugfs or tracefs is configured, which means you probably 97 * want some tracepoint which wasn't compiled in your kernel. 98 * - jirka 99 */ 100 if (debugfs__configured() || tracefs__configured()) { 101 snprintf(buf, size, 102 "Error:\tFile %s/%s not found.\n" 103 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n", 104 tracing_events_path, filename); 105 break; 106 } 107 snprintf(buf, size, "%s", 108 "Error:\tUnable to find debugfs/tracefs\n" 109 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n" 110 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n" 111 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'"); 112 break; 113 case EACCES: { 114 snprintf(buf, size, 115 "Error:\tNo permissions to read %s/%s\n" 116 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n", 117 tracing_events_path, filename, tracing_mnt); 118 } 119 break; 120 default: 121 snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf))); 122 break; 123 } 124 125 return 0; 126 } 127 128 int tracing_path__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name) 129 { 130 char path[PATH_MAX]; 131 132 snprintf(path, PATH_MAX, "%s/%s", sys, name ?: "*"); 133 134 return strerror_open(err, buf, size, path); 135 } 136