179 lines · c
1// SPDX-License-Identifier: GPL-2.02#ifndef _GNU_SOURCE3# define _GNU_SOURCE4#endif5 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 16static char tracing_path[PATH_MAX] = "/sys/kernel/tracing";17 18static 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 24static 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 37static 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 50const 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 63void tracing_path_set(const char *mntpt)64{65 __tracing_path_set("tracing/", mntpt);66}67 68char *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 78void put_tracing_file(char *file)79{80 free(file);81}82 83char *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 93void put_events_file(char *file)94{95 free(file);96}97 98DIR *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 111int 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 127int 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 of139 * debugfs or tracefs is configured, which means you probably140 * want some tracepoint which wasn't compiled in your kernel.141 * - jirka142 */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