1 // SPDX-License-Identifier: GPL-2.0 2 #ifndef _GNU_SOURCE 3 # define _GNU_SOURCE 4 #endif 5 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <string.h> 9 #include <linux/string.h> 10 #include <errno.h> 11 #include <unistd.h> 12 #include "fs.h" 13 14 #include "tracing_path.h" 15 16 static char tracing_path[PATH_MAX] = "/sys/kernel/tracing"; 17 18 static void __tracing_path_set(const char *tracing, const char *mountpoint) 19 { 20 snprintf(tracing_path, sizeof(tracing_path), "%s/%s", 21 mountpoint, tracing); 22 } 23 24 static const char *tracing_path_tracefs_mount(void) 25 { 26 const char *mnt; 27 28 mnt = tracefs__mount(); 29 if (!mnt) 30 return NULL; 31 32 __tracing_path_set("", mnt); 33 34 return tracing_path; 35 } 36 37 static const char *tracing_path_debugfs_mount(void) 38 { 39 const char *mnt; 40 41 mnt = debugfs__mount(); 42 if (!mnt) 43 return NULL; 44 45 __tracing_path_set("tracing/", mnt); 46 47 return tracing_path; 48 } 49 50 const char *tracing_path_mount(void) 51 { 52 const char *mnt; 53 54 mnt = tracing_path_tracefs_mount(); 55 if (mnt) 56 return mnt; 57 58 mnt = tracing_path_debugfs_mount(); 59 60 return mnt; 61 } 62 63 void tracing_path_set(const char *mntpt) 64 { 65 __tracing_path_set("tracing/", mntpt); 66 } 67 68 char *get_tracing_file(const char *name) 69 { 70 char *file; 71 72 if (asprintf(&file, "%s/%s", tracing_path_mount(), name) < 0) 73 return NULL; 74 75 return file; 76 } 77 78 void put_tracing_file(char *file) 79 { 80 free(file); 81 } 82 83 char *get_events_file(const char *name) 84 { 85 char *file; 86 87 if (asprintf(&file, "%s/events/%s", tracing_path_mount(), name) < 0) 88 return NULL; 89 90 return file; 91 } 92 93 void put_events_file(char *file) 94 { 95 free(file); 96 } 97 98 DIR *tracing_events__opendir(void) 99 { 100 DIR *dir = NULL; 101 char *path = get_tracing_file("events"); 102 103 if (path) { 104 dir = opendir(path); 105 put_events_file(path); 106 } 107 108 return dir; 109 } 110 111 int tracing_events__scandir_alphasort(struct dirent ***namelist) 112 { 113 char *path = get_tracing_file("events"); 114 int ret; 115 116 if (!path) { 117 *namelist = NULL; 118 return 0; 119 } 120 121 ret = scandir(path, namelist, NULL, alphasort); 122 put_events_file(path); 123 124 return ret; 125 } 126 127 int tracing_path__strerror_open_tp(int err, char *buf, size_t size, 128 const char *sys, const char *name) 129 { 130 char sbuf[128]; 131 char filename[PATH_MAX]; 132 133 snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*"); 134 135 switch (err) { 136 case ENOENT: 137 /* 138 * We will get here if we can't find the tracepoint, but one of 139 * debugfs or tracefs is configured, which means you probably 140 * want some tracepoint which wasn't compiled in your kernel. 141 * - jirka 142 */ 143 if (debugfs__configured() || tracefs__configured()) { 144 /* sdt markers */ 145 if (!strncmp(filename, "sdt_", 4)) { 146 snprintf(buf, size, 147 "Error:\tFile %s/events/%s not found.\n" 148 "Hint:\tSDT event cannot be directly recorded on.\n" 149 "\tPlease first use 'perf probe %s:%s' before recording it.\n", 150 tracing_path, filename, sys, name); 151 } else { 152 snprintf(buf, size, 153 "Error:\tFile %s/events/%s not found.\n" 154 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n", 155 tracing_path, filename); 156 } 157 break; 158 } 159 snprintf(buf, size, "%s", 160 "Error:\tUnable to find debugfs/tracefs\n" 161 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n" 162 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n" 163 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'"); 164 break; 165 case EACCES: { 166 snprintf(buf, size, 167 "Error:\tNo permissions to read %s/events/%s\n" 168 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n", 169 tracing_path, filename, tracing_path_mount()); 170 } 171 break; 172 default: 173 snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf))); 174 break; 175 } 176 177 return 0; 178 } 179