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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
* mdadm - manage Linux "md" devices aka RAID arrays.
*
* Copyright (C) 2022 Mateusz Grzonka <mateusz.grzonka@intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "mdadm.h"
#include "udev.h"
#include "md_p.h"
#include "md_u.h"
#include "xmalloc.h"
#include <sys/wait.h>
#include <signal.h>
#include <limits.h>
#include <syslog.h>
#ifndef NO_LIBUDEV
#include <libudev.h>
#endif
static char *unblock_path;
/*
* udev_is_available() - Checks for udev in the system.
*
* Function looks whether udev directories are available and MDADM_NO_UDEV env defined.
*
* Return:
* true if udev is available,
* false if not
*/
bool udev_is_available(void)
{
struct stat stb;
if (stat("/dev/.udev", &stb) != 0 &&
stat("/run/udev", &stb) != 0)
return false;
if (check_env("MDADM_NO_UDEV") == 1)
return false;
return true;
}
#ifndef NO_LIBUDEV
static struct udev *udev;
static struct udev_monitor *udev_monitor;
/*
* udev_release() - Drops references of udev and udev_monitor.
*/
static void udev_release(void)
{
udev_monitor_unref(udev_monitor);
udev_unref(udev);
}
/*
* udev_initialize() - Initializes udev and udev_monitor structures.
*
* Function initializes udev, udev_monitor, and sets udev_monitor filter for block devices.
*
* Return:
* UDEV_STATUS_SUCCESS on success
* UDEV_STATUS_ERROR on error
* UDEV_STATUS_ERROR_NO_UDEV when udev not available
*/
static enum udev_status udev_initialize(void)
{
if (!udev_is_available()) {
pr_err("No udev.\n");
return UDEV_STATUS_ERROR_NO_UDEV;
}
udev = udev_new();
if (!udev) {
pr_err("Cannot initialize udev.\n");
return UDEV_STATUS_ERROR;
}
udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
if (!udev_monitor) {
pr_err("Cannot initialize udev monitor.\n");
udev = udev_unref(udev);
return UDEV_STATUS_ERROR;
}
if (udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "block", 0) < 0) {
pr_err("Cannot add udev monitor event filter for md devices.\n");
udev_release();
return UDEV_STATUS_ERROR;
}
if (udev_monitor_enable_receiving(udev_monitor) < 0) {
pr_err("Cannot enable receiving udev events through udev monitor.\n");
udev_release();
return UDEV_STATUS_ERROR;
}
atexit(udev_release);
return UDEV_STATUS_SUCCESS;
}
/*
* udev_wait_for_events() - Waits for events from udev.
* @seconds: Timeout in seconds.
*
* Function waits udev events, wakes up on event or timeout.
*
* Return:
* UDEV_STATUS_SUCCESS on detected event
* UDEV_STATUS_TIMEOUT on timeout
* UDEV_STATUS_ERROR on error
*/
enum udev_status udev_wait_for_events(int seconds)
{
int fd;
fd_set readfds;
struct timeval tv;
int ret;
if (!udev || !udev_monitor) {
ret = udev_initialize();
if (ret != UDEV_STATUS_SUCCESS)
return ret;
}
fd = udev_monitor_get_fd(udev_monitor);
if (fd < 0) {
pr_err("Cannot access file descriptor associated with udev monitor.\n");
return UDEV_STATUS_ERROR;
}
FD_ZERO(&readfds);
FD_SET(fd, &readfds);
tv.tv_sec = seconds;
tv.tv_usec = 0;
if (select(fd + 1, &readfds, NULL, NULL, &tv) > 0 && FD_ISSET(fd, &readfds)) {
struct udev_device *dev = udev_monitor_receive_device(udev_monitor);
if (dev) {
udev_device_unref(dev);
return UDEV_STATUS_SUCCESS; /* event detected */
}
}
return UDEV_STATUS_TIMEOUT;
}
#endif
/*
* udev_block() - Block udev from examining newly created arrays.
*
* When array is created, we don't want udev to examine it immediately.
* Function creates /run/mdadm/creating-mdXXX and expects that udev rule
* will notice it and act accordingly.
*
* Return:
* UDEV_STATUS_SUCCESS when successfully blocked udev
* UDEV_STATUS_ERROR on error
*/
enum udev_status udev_block(char *devnm)
{
int fd;
char *path = xcalloc(1, BUFSIZ);
snprintf(path, BUFSIZ, "/run/mdadm/creating-%s", devnm);
fd = open(path, O_CREAT | O_RDWR, 0600);
if (!is_fd_valid(fd)) {
pr_err("Cannot block udev, error creating blocking file.\n");
pr_err("%s: %s\n", strerror(errno), path);
free(path);
return UDEV_STATUS_ERROR;
}
close(fd);
unblock_path = path;
return UDEV_STATUS_SUCCESS;
}
/*
* udev_unblock() - Unblock udev.
*/
void udev_unblock(void)
{
if (unblock_path)
unlink(unblock_path);
free(unblock_path);
unblock_path = NULL;
}
|
