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] = "/sys/kernel/debug";
16 char tracing_path[PATH_MAX] = "/sys/kernel/debug/tracing";
17 char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";
18
19
__tracing_path_set(const char * tracing,const char * mountpoint)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
tracing_path_tracefs_mount(void)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
tracing_path_debugfs_mount(void)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
tracing_path_mount(void)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
tracing_path_set(const char * mntpt)68 void tracing_path_set(const char *mntpt)
69 {
70 __tracing_path_set("tracing/", mntpt);
71 }
72
get_tracing_file(const char * name)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
put_tracing_file(char * file)83 void put_tracing_file(char *file)
84 {
85 free(file);
86 }
87
strerror_open(int err,char * buf,size_t size,const char * filename)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
tracing_path__strerror_open_tp(int err,char * buf,size_t size,const char * sys,const char * name)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