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}