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
| | /*
* Copyright (C) 2012-2020 all contributors <cmogstored-public@yhbt.net>
* License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
*/
#include "cmogstored.h"
#if MOG_SELFPIPE
struct mog_fd * mog_selfwake_new(void)
{
struct mog_fd *reader, *writer;
struct mog_selfwake *selfwake;
int self_pipe[2];
if (pipe2(self_pipe, O_NONBLOCK | O_CLOEXEC) < 0)
die_errno("failed to init self-pipe");
reader = mog_fd_init(self_pipe[0], MOG_FD_TYPE_SELFWAKE);
selfwake = &reader->as.selfwake;
writer = mog_fd_init(self_pipe[1], MOG_FD_TYPE_SELFPIPE);
writer->as.selfpipe.reader = reader;
selfwake->writer = writer;
return reader;
}
static ssize_t selfwake_drain(struct mog_fd *mfd)
{
char buf[64];
return read(mfd->fd, buf, sizeof(buf));
}
/* this allows interrupts */
void mog_selfwake_wait(struct mog_fd *mfd)
{
/* poll() on a pipe does not work on some *BSDs, so just block */
mog_set_nonblocking(mfd->fd, false);
mog_intr_enable();
(void)selfwake_drain(mfd);
mog_intr_disable();
mog_set_nonblocking(mfd->fd, true);
mog_selfwake_drain(mfd);
}
static void selfwake_trigger(struct mog_fd *mfd)
{
ssize_t w;
retry:
w = write(mfd->as.selfwake.writer->fd, "", 1);
if (w >= 0) return;
switch (errno) {
case_EAGAIN: return; /* somebody already woke this up */
case EINTR: goto retry; /* just in case... */
}
/*
* we're screwed anyways, at least try this even though syslog()
* isn't safe inside a signal handler.
*/
syslog(LOG_CRIT, "mog_selfwake_trigger write() failed: %m");
abort();
}
/* this is async-signal safe (except in the case of our usage bugs) */
void mog_selfwake_trigger(struct mog_fd *mfd)
{
PRESERVE_ERRNO(selfwake_trigger(mfd));
}
void mog_selfwake_drain(struct mog_fd *mfd)
{
ssize_t r;
do {
r = selfwake_drain(mfd);
} while (r > 0);
assert(r < 0 && (errno == EAGAIN || errno == EINTR)
&& "selfwake read failed");
}
#endif /* MOG_SELFPIPE */
|