summaryrefslogtreecommitdiffstats
path: root/src/systemd.c
blob: fb36dd993f9dee101b8d58d7458f9378e8aef3c7 (plain)
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
/* SPDX-License-Identifier: MIT-0 */

/* Implement the systemd notify protocol without external dependencies.
 * Supports both readiness notification on startup and on reloading,
 * according to the protocol defined at:
 * https://www.freedesktop.org/software/systemd/man/latest/sd_notify.html
 * This protocol is guaranteed to be stable as per:
 * https://systemd.io/PORTABILITY_AND_STABILITY/
 *
 */

#include <errno.h>
#include <inttypes.h>
#include <signal.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <time.h>
#include <unistd.h>
#include <stdarg.h>

#include <haproxy/tools.h>

/*
 *  standalone reimplementation of sd_notify from the libsystemd
 *  Return:
 *     -errno in case of error
 *     0 when ignored
 *     >0 when succeeded
 *
 * Will send <message> over the NOTIFY_SOCKET.
 * When unset_environement is set, unsetenv NOTIFY_SOCKET.
 */
int sd_notify(int unset_environment, const char *message)
{
	union sockaddr_union {
		struct sockaddr sa;
		struct sockaddr_un sun;
	} socket_addr = {
		.sun.sun_family = AF_UNIX,
	};
	int ret = 1;
	int fd = -1;
	size_t path_length, message_length;
	const char *socket_path;
	ssize_t written;

	socket_path = getenv("NOTIFY_SOCKET");
	if (!socket_path) {
		ret = 0; /* Not running under systemd? Nothing to do */
		goto end;
	}

	if (unset_environment)
		unsetenv("NOTIFY_SOCKET");

	if (!message) {
		ret = -EINVAL;
		goto end;
	}

	message_length = strlen(message);
	if (message_length == 0) {
		ret = -EINVAL;
		goto end;
	}

	/* Only AF_UNIX is supported, with path or abstract sockets */
	if (socket_path[0] != '/' && socket_path[0] != '@') {
		ret = -EAFNOSUPPORT;
		goto end;
	}

	path_length = strlen(socket_path);
	/* Ensure there is room for NUL byte */
	if (path_length >= sizeof(socket_addr.sun.sun_path)) {
		ret = -E2BIG;
		goto end;
	}

	memcpy(socket_addr.sun.sun_path, socket_path, path_length);

	/* Support for abstract socket */
	if (socket_addr.sun.sun_path[0] == '@')
		socket_addr.sun.sun_path[0] = 0;

	fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
	if (fd < 0) {
		ret = -errno;
		goto end;
	}

	if (connect(fd, &socket_addr.sa, offsetof(struct sockaddr_un, sun_path) + path_length) != 0) {
		ret = -errno;
		goto end;
	}

	written = write(fd, message, message_length);
	if (written != (ssize_t) message_length) {
		ret = written < 0 ? -errno : -EPROTO;
		goto end;
	}

end:
	if (fd > -1)
		close(fd);
	return ret; /* Notified! */
}

/* va_args variant of sd_notify */
int sd_notifyf(int unset_environment, const char *format, ...)
{
	int r;
	va_list args;
	char *strp = NULL;

	va_start(args, format);
	strp = memvprintf(&strp, format, args);
	va_end(args);

	if (strp == NULL) {
		r = -ENOMEM;
		goto end;
	}

	r = sd_notify(unset_environment, strp);
	free(strp);
end:
	return r;
}