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
|
/* vi: set sw=4 ts=4: */
/*
* simple inotify daemon
* reports filesystem changes via userspace agent
*
* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
/*
* Use as follows:
* # inotifyd /user/space/agent dir/or/file/being/watched[:mask] ...
*
* When a filesystem event matching the specified mask is occured on specified file (or directory)
* a userspace agent is spawned and given the following parameters:
* $1. actual event(s)
* $2. file (or directory) name
* $3. name of subfile (if any), in case of watching a directory
*
* E.g. inotifyd ./dev-watcher /dev:n
*
* ./dev-watcher can be, say:
* #!/bin/sh
* echo "We have new device in here! Hello, $3!"
*
* See below for mask names explanation.
*/
#include "libbb.h"
#include <sys/inotify.h>
static const char mask_names[] ALIGN1 =
"a" // 0x00000001 File was accessed
"c" // 0x00000002 File was modified
"e" // 0x00000004 Metadata changed
"w" // 0x00000008 Writtable file was closed
"0" // 0x00000010 Unwrittable file closed
"r" // 0x00000020 File was opened
"m" // 0x00000040 File was moved from X
"y" // 0x00000080 File was moved to Y
"n" // 0x00000100 Subfile was created
"d" // 0x00000200 Subfile was deleted
"D" // 0x00000400 Self was deleted
"M" // 0x00000800 Self was moved
;
extern int inotify_init(void);
extern int inotify_add_watch(int fd, const char *path, uint32_t mask);
int inotifyd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int inotifyd_main(int argc UNUSED_PARAM, char **argv)
{
int n;
unsigned mask = IN_ALL_EVENTS; // assume we want all events
struct pollfd pfd;
char **watched = ++argv; // watched name list
const char *args[] = { *argv, NULL, NULL, NULL, NULL };
// sanity check: agent and at least one watch must be given
if (!argv[1])
bb_show_usage();
// open inotify
pfd.fd = inotify_init();
if (pfd.fd < 0)
bb_perror_msg_and_die("no kernel support");
// setup watched
while (*++argv) {
char *path = *argv;
char *masks = strchr(path, ':');
// if mask is specified ->
if (masks) {
*masks = '\0'; // split path and mask
// convert mask names to mask bitset
mask = 0;
while (*++masks) {
int i = strchr(mask_names, *masks) - mask_names;
if (i >= 0) {
mask |= (1 << i);
}
}
}
// add watch
n = inotify_add_watch(pfd.fd, path, mask);
if (n < 0)
bb_perror_msg_and_die("add watch (%s) failed", path);
//bb_error_msg("added %d [%s]:%4X", n, path, mask);
}
// setup signals
bb_signals(BB_FATAL_SIGS, record_signo);
// do watch
pfd.events = POLLIN;
while (1) {
ssize_t len;
void *buf;
struct inotify_event *ie;
again:
if (bb_got_signal)
break;
n = poll(&pfd, 1, -1);
/* Signal interrupted us? */
if (n < 0 && errno == EINTR)
goto again;
// Under Linux, above if() is not necessary.
// Non-fatal signals, e.g. SIGCHLD, when set to SIG_DFL,
// are not interrupting poll().
// Thus we can just break if n <= 0 (see below),
// because EINTR will happen only on SIGTERM et al.
// But this might be not true under other Unixes,
// and is generally way too subtle to depend on.
if (n <= 0) // strange error?
break;
// read out all pending events
xioctl(pfd.fd, FIONREAD, &len);
#define eventbuf bb_common_bufsiz1
ie = buf = (len <= sizeof(eventbuf)) ? eventbuf : xmalloc(len);
len = full_read(pfd.fd, buf, len);
// process events. N.B. events may vary in length
while (len > 0) {
int i;
char events[sizeof(mask_names)];
char *s = events;
unsigned m = ie->mask;
for (i = 0; i < sizeof(mask_names)-1; ++i, m >>= 1) {
if (m & 1)
*s++ = mask_names[i];
}
*s = '\0';
//bb_error_msg("exec %s %08X\t%s\t%s\t%s", agent,
// ie->mask, events, watched[ie->wd], ie->len ? ie->name : "");
args[1] = events;
args[2] = watched[ie->wd];
args[3] = ie->len ? ie->name : NULL;
wait4pid(xspawn((char **)args));
// next event
i = sizeof(struct inotify_event) + ie->len;
len -= i;
ie = (void*)((char*)ie + i);
}
if (eventbuf != buf)
free(buf);
}
return EXIT_SUCCESS;
}
|
