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
__tracing_path_set(const char * tracing,const char * mountpoint)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
tracing_path_tracefs_mount(void)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
tracing_path_debugfs_mount(void)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
tracing_path_mount(void)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
tracing_path_set(const char * mntpt)63 void tracing_path_set(const char *mntpt)
64 {
65 __tracing_path_set("tracing/", mntpt);
66 }
67
get_tracing_file(const char * name)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
put_tracing_file(char * file)78 void put_tracing_file(char *file)
79 {
80 free(file);
81 }
82
get_events_file(const char * name)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
put_events_file(char * file)93 void put_events_file(char *file)
94 {
95 free(file);
96 }
97
tracing_events__opendir(void)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
tracing_events__scandir_alphasort(struct dirent *** namelist)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
tracing_path__strerror_open_tp(int err,char * buf,size_t size,const char * sys,const char * name)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