-
Notifications
You must be signed in to change notification settings - Fork 2
/
debugfs.c
160 lines (128 loc) · 3.6 KB
/
debugfs.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
/*
* Copyright (C) 2009 Clark Williams <[email protected]>
* Copyright (C) 2009 Xiao Guangrong <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*
*/
#include "debugfs.h"
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#ifndef DEBUGFS_MAGIC
#define DEBUGFS_MAGIC 0x64626720
#endif
static int debugfs_premounted;
static char debugfs_mountpoint[MAX_PATH+1];
static const char *debugfs_find_mountpoint(void);
static int debugfs_valid_mountpoint(const char *debugfs);
static const char *debugfs_known_mountpoints[] = {
"/sys/kernel/debug/",
"/debug/",
NULL,
};
/* construct a full path to a debugfs element */
int debugfs_make_path(const char *fmt, const char *mesh_iface, char *buffer,
int size)
{
int len;
if (strlen(debugfs_mountpoint) == 0) {
buffer[0] = '\0';
return -1;
}
len = strlen(debugfs_mountpoint) + strlen(fmt) + 1;
if (len >= size)
return len+1;
snprintf(buffer, size-1, fmt, debugfs_mountpoint, mesh_iface);
return 0;
}
static int debugfs_found;
/* find the path to the mounted debugfs */
static const char *debugfs_find_mountpoint(void)
{
const char **ptr;
char type[100];
FILE *fp;
if (debugfs_found)
return (const char *)debugfs_mountpoint;
ptr = debugfs_known_mountpoints;
while (*ptr) {
if (debugfs_valid_mountpoint(*ptr) == 0) {
debugfs_found = 1;
strncpy(debugfs_mountpoint, *ptr,
sizeof(debugfs_mountpoint));
debugfs_mountpoint[sizeof(debugfs_mountpoint) - 1] = 0;
return debugfs_mountpoint;
}
ptr++;
}
/* give up and parse /proc/mounts */
fp = fopen("/proc/mounts", "r");
if (fp == NULL) {
perror("Error - can't open /proc/mounts for read");
return NULL;
}
while (fscanf(fp, "%*s %"
STR(MAX_PATH)
"s %99s %*s %*d %*d\n",
debugfs_mountpoint, type) == 2) {
if (strcmp(type, "debugfs") == 0)
break;
}
fclose(fp);
if (strcmp(type, "debugfs") != 0)
return NULL;
debugfs_found = 1;
return debugfs_mountpoint;
}
/* verify that a mountpoint is actually a debugfs instance */
static int debugfs_valid_mountpoint(const char *debugfs)
{
struct statfs st_fs;
if (statfs(debugfs, &st_fs) < 0)
return -ENOENT;
else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
return -ENOENT;
return 0;
}
int debugfs_valid_entry(const char *path)
{
struct stat st;
if (stat(path, &st))
return -errno;
return 0;
}
/* mount the debugfs somewhere if it's not mounted */
char *debugfs_mount(const char *mountpoint)
{
/* see if it's already mounted */
if (debugfs_find_mountpoint()) {
debugfs_premounted = 1;
return debugfs_mountpoint;
}
/* if not mounted and no argument */
if (mountpoint == NULL)
mountpoint = "/sys/kernel/debug";
if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)
return NULL;
/* save the mountpoint */
strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
debugfs_mountpoint[sizeof(debugfs_mountpoint) - 1] = '\0';
debugfs_found = 1;
return debugfs_mountpoint;
}