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1 /*
2 * udevsend.c
3 *
4 * Userspace devfs
5 *
6 * Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
7 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
8 *
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation version 2 of the License.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 675 Mass Ave, Cambridge, MA 02139, USA.
22 *
23 */
24
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <sys/wait.h>
28 #include <sys/un.h>
29 #include <time.h>
30 #include <errno.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <stddef.h>
34 #include <string.h>
35 #include <unistd.h>
36 #include <linux/stddef.h>
37
38 #include "udev.h"
39 #include "udev_lib.h"
40 #include "udev_version.h"
41 #include "udevd.h"
42 #include "logging.h"
43
44 #ifdef LOG
45 unsigned char logname[LOGNAME_SIZE];
46 void log_message (int level, const char *format, ...)
47 {
48 va_list args;
49
50 va_start(args, format);
51 vsyslog(level, format, args);
52 va_end(args);
53 }
54 #endif
55
56 static int start_daemon(void)
57 {
58 pid_t pid;
59 pid_t child_pid;
60
61 pid = fork();
62 switch (pid) {
63 case 0:
64 /* helper child */
65 child_pid = fork();
66 switch (child_pid) {
67 case 0:
68 /* daemon */
69 setsid();
70 chdir("/");
71 execl(UDEVD_BIN, "udevd", NULL);
72 dbg("exec of daemon failed");
73 exit(1);
74 case -1:
75 dbg("fork of daemon failed");
76 return -1;
77 default:
78 exit(0);
79 }
80 break;
81 case -1:
82 dbg("fork of helper failed");
83 return -1;
84 default:
85 waitpid(pid, NULL, 0);
86 }
87 return 0;
88 }
89
90 static void run_udev(const char *subsystem)
91 {
92 pid_t pid;
93
94 pid = fork();
95 switch (pid) {
96 case 0:
97 /* child */
98 execl(UDEV_BIN, UDEV_BIN, subsystem, NULL);
99 dbg("exec of child failed");
100 _exit(1);
101 break;
102 case -1:
103 dbg("fork of child failed");
104 break;
105 default:
106 waitpid(pid, NULL, 0);
107 }
108 }
109
110 int main(int argc, char* argv[])
111 {
112 struct hotplug_msg msg;
113 char *action;
114 char *devpath;
115 char *subsystem;
116 char *seqnum;
117 unsigned long long seq;
118 int retval = 1;
119 int loop;
120 int sock = -1;
121 struct sockaddr_un saddr;
122 socklen_t addrlen;
123 int started_daemon = 0;
124
125 logging_init("udevsend");
126 dbg("version %s", UDEV_VERSION);
127
128 subsystem = get_subsystem(argv[1]);
129 if (subsystem == NULL) {
130 dbg("no subsystem");
131 goto exit;
132 }
133 dbg("subsystem = '%s'", subsystem);
134
135 devpath = get_devpath();
136 if (devpath == NULL) {
137 dbg("no devpath");
138 goto exit;
139 }
140 dbg("DEVPATH = '%s'", devpath);
141
142 action = get_action();
143 if (action == NULL) {
144 dbg("no action");
145 goto exit;
146 }
147 dbg("ACTION = '%s'", action);
148
149 seqnum = get_seqnum();
150 if (seqnum == NULL)
151 seq = 0;
152 else
153 seq = strtoull(seqnum, NULL, 10);
154 dbg("SEQNUM = '%llu'", seq);
155
156 sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
157 if (sock == -1) {
158 dbg("error getting socket");
159 goto fallback;
160 }
161
162 set_cloexec_flag(sock, 1);
163
164 memset(&saddr, 0x00, sizeof(struct sockaddr_un));
165 saddr.sun_family = AF_LOCAL;
166 /* use abstract namespace for socket path */
167 strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
168 addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
169
170 memset(&msg, 0x00, sizeof(struct hotplug_msg));
171 strcpy(msg.magic, UDEV_MAGIC);
172 msg.seqnum = seq;
173 strfieldcpy(msg.action, action);
174 strfieldcpy(msg.devpath, devpath);
175 strfieldcpy(msg.subsystem, subsystem);
176
177 /* If we can't send, try to start daemon and resend message */
178 loop = SEND_WAIT_MAX_SECONDS * SEND_WAIT_LOOP_PER_SECOND;
179 while (--loop) {
180 retval = sendto(sock, &msg, sizeof(struct hotplug_msg), 0,
181 (struct sockaddr *)&saddr, addrlen);
182 if (retval != -1) {
183 retval = 0;
184 goto exit;
185 }
186
187 if (errno != ECONNREFUSED) {
188 dbg("error sending message");
189 goto fallback;
190 }
191
192 if (!started_daemon) {
193 info("starting udevd daemon");
194 retval = start_daemon();
195 if (retval) {
196 info("error starting daemon");
197 goto fallback;
198 }
199 dbg("daemon started");
200 started_daemon = 1;
201 } else {
202 dbg("retry to connect %d", SEND_WAIT_MAX_SECONDS * SEND_WAIT_LOOP_PER_SECOND - loop);
203 usleep(1000 * 1000 / SEND_WAIT_LOOP_PER_SECOND);
204 }
205 }
206
207 fallback:
208 info("unable to connect to event daemon, try to call udev directly");
209 run_udev(subsystem);
210
211 exit:
212 if (sock != -1)
213 close(sock);
214
215 logging_close();
216
217 return retval;
218 }