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 <linux/string.h> 9 #include <errno.h> 10 #include <unistd.h> 11 #include "fs.h" 12 13 #include "tracing_path.h" 14 15 16 char tracing_mnt[PATH_MAX] = "/sys/kernel/debug"; 17 char tracing_path[PATH_MAX] = "/sys/kernel/debug/tracing"; 18 char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events"; 19 20 21 static void __tracing_path_set(const char *tracing, const char *mountpoint) 22 { 23 snprintf(tracing_mnt, sizeof(tracing_mnt), "%s", mountpoint); 24 snprintf(tracing_path, sizeof(tracing_path), "%s/%s", 25 mountpoint, tracing); 26 snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s%s", 27 mountpoint, tracing, "events"); 28 } 29 30 static const char *tracing_path_tracefs_mount(void) 31 { 32 const char *mnt; 33 34 mnt = tracefs__mount(); 35 if (!mnt) 36 return NULL; 37 38 __tracing_path_set("", mnt); 39 40 return mnt; 41 } 42 43 static const char *tracing_path_debugfs_mount(void) 44 { 45 const char *mnt; 46 47 mnt = debugfs__mount(); 48 if (!mnt) 49 return NULL; 50 51 __tracing_path_set("tracing/", mnt); 52 53 return mnt; 54 } 55 56 const char *tracing_path_mount(void) 57 { 58 const char *mnt; 59 60 mnt = tracing_path_tracefs_mount(); 61 if (mnt) 62 return mnt; 63 64 mnt = tracing_path_debugfs_mount(); 65 66 return mnt; 67 } 68 69 void tracing_path_set(const char *mntpt) 70 { 71 __tracing_path_set("tracing/", mntpt); 72 } 73 74 char *get_tracing_file(const char *name) 75 { 76 char *file; 77 78 if (asprintf(&file, "%s/%s", tracing_path, name) < 0) 79 return NULL; 80 81 return file; 82 } 83 84 void put_tracing_file(char *file) 85 { 86 free(file); 87 } 88 89 int tracing_path__strerror_open_tp(int err, char *buf, size_t size, 90 const char *sys, const char *name) 91 { 92 char sbuf[128]; 93 char filename[PATH_MAX]; 94 95 snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*"); 96 97 switch (err) { 98 case ENOENT: 99 /* 100 * We will get here if we can't find the tracepoint, but one of 101 * debugfs or tracefs is configured, which means you probably 102 * want some tracepoint which wasn't compiled in your kernel. 103 * - jirka 104 */ 105 if (debugfs__configured() || tracefs__configured()) { 106 /* sdt markers */ 107 if (!strncmp(filename, "sdt_", 4)) { 108 snprintf(buf, size, 109 "Error:\tFile %s/%s not found.\n" 110 "Hint:\tSDT event cannot be directly recorded on.\n" 111 "\tPlease first use 'perf probe %s:%s' before recording it.\n", 112 tracing_events_path, filename, sys, name); 113 } else { 114 snprintf(buf, size, 115 "Error:\tFile %s/%s not found.\n" 116 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n", 117 tracing_events_path, filename); 118 } 119 break; 120 } 121 snprintf(buf, size, "%s", 122 "Error:\tUnable to find debugfs/tracefs\n" 123 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n" 124 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n" 125 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'"); 126 break; 127 case EACCES: { 128 snprintf(buf, size, 129 "Error:\tNo permissions to read %s/%s\n" 130 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n", 131 tracing_events_path, filename, tracing_mnt); 132 } 133 break; 134 default: 135 snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf))); 136 break; 137 } 138 139 return 0; 140 } 141