Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
16char tracing_mnt[PATH_MAX] = "/sys/kernel/debug";
17char tracing_path[PATH_MAX] = "/sys/kernel/debug/tracing";
18char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";
19
20
21static 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
30static 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
43static 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
56const 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
69void tracing_path_set(const char *mntpt)
70{
71 __tracing_path_set("tracing/", mntpt);
72}
73
74char *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
84void put_tracing_file(char *file)
85{
86 free(file);
87}
88
89static int strerror_open(int err, char *buf, size_t size, const char *filename)
90{
91 char sbuf[128];
92
93 switch (err) {
94 case ENOENT:
95 /*
96 * We will get here if we can't find the tracepoint, but one of
97 * debugfs or tracefs is configured, which means you probably
98 * want some tracepoint which wasn't compiled in your kernel.
99 * - jirka
100 */
101 if (debugfs__configured() || tracefs__configured()) {
102 snprintf(buf, size,
103 "Error:\tFile %s/%s not found.\n"
104 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
105 tracing_events_path, filename);
106 break;
107 }
108 snprintf(buf, size, "%s",
109 "Error:\tUnable to find debugfs/tracefs\n"
110 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n"
111 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n"
112 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
113 break;
114 case EACCES: {
115 snprintf(buf, size,
116 "Error:\tNo permissions to read %s/%s\n"
117 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
118 tracing_events_path, filename, tracing_mnt);
119 }
120 break;
121 default:
122 snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
123 break;
124 }
125
126 return 0;
127}
128
129int tracing_path__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name)
130{
131 char path[PATH_MAX];
132
133 snprintf(path, PATH_MAX, "%s/%s", sys, name ?: "*");
134
135 return strerror_open(err, buf, size, path);
136}