udevmonitor.c

   1 /*
   2  * udevmonitor.c
   3  *
   4  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  *
  10  *      This program is distributed in the hope that it will be useful, but
  11  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *      General Public License for more details.
  14  *
  15  *      You should have received a copy of the GNU General Public License along
  16  *      with this program; if not, write to the Free Software Foundation, Inc.,
  17  *      675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  */
  20
  21 #include <unistd.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <stddef.h>
  25 #include <string.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <signal.h>
  29 #include <sys/time.h>
  30 #include <sys/socket.h>
  31 #include <sys/un.h>
  32 #include <sys/select.h>
  33 #include <linux/types.h>
  34 #include <linux/netlink.h>
  35
  36 #include "udev.h"
  37 #include "udevd.h"
  38
  39 static int uevent_netlink_sock = -1;
  40 static int udev_monitor_sock = -1;
  41 static volatile int udev_exit;
  42
  43 static int init_udev_monitor_socket(void)
  44 {
  45         struct sockaddr_un saddr;
  46         socklen_t addrlen;
  47         const int feature_on = 1;
  48         int retval;
  49
  50         memset(&saddr, 0x00, sizeof(saddr));
  51         saddr.sun_family = AF_LOCAL;
  52         /* use abstract namespace for socket path */
  53         strcpy(&saddr.sun_path[1], "/org/kernel/udev/monitor");
  54         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
  55
  56         udev_monitor_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  57         if (udev_monitor_sock == -1) {
  58                 fprintf(stderr, "error getting socket: %s\n", strerror(errno));
  59                 return -1;
  60         }
  61
  62         /* the bind takes care of ensuring only one copy running */
  63         retval = bind(udev_monitor_sock, (struct sockaddr *) &saddr, addrlen);
  64         if (retval < 0) {
  65                 fprintf(stderr, "bind failed: %s\n", strerror(errno));
  66                 close(udev_monitor_sock);
  67                 udev_monitor_sock = -1;
  68                 return -1;
  69         }
  70
  71         /* enable receiving of the sender credentials */
  72         setsockopt(udev_monitor_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
  73
  74         return 0;
  75 }
  76
  77 static int init_uevent_netlink_sock(void)
  78 {
  79         struct sockaddr_nl snl;
  80         int retval;
  81
  82         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
  83         snl.nl_family = AF_NETLINK;
  84         snl.nl_pid = getpid();
  85         snl.nl_groups = 1;
  86
  87         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
  88         if (uevent_netlink_sock == -1) {
  89                 fprintf(stderr, "error getting socket: %s\n", strerror(errno));
  90                 return -1;
  91         }
  92
  93         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl,
  94                       sizeof(struct sockaddr_nl));
  95         if (retval < 0) {
  96                 fprintf(stderr, "bind failed: %s\n", strerror(errno));
  97                 close(uevent_netlink_sock);
  98                 uevent_netlink_sock = -1;
  99                 return -1;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static void asmlinkage sig_handler(int signum)
 106 {
 107         if (signum == SIGINT || signum == SIGTERM)
 108                 udev_exit = 1;
 109 }
 110
 111 int main(int argc, char *argv[])
 112 {
 113         struct sigaction act;
 114         int env = 0;
 115         fd_set readfds;
 116         int i;
 117         int retval = 0;
 118
 119         for (i = 1 ; i < argc; i++) {
 120                 char *arg = argv[i];
 121                 if (strcmp(arg, "--env") == 0 || strcmp(arg, "-e") == 0)
 122                         env = 1;
 123                 else if (strcmp(arg, "--help") == 0  || strcmp(arg, "-h") == 0){
 124                         printf("Usage: udevmonitor [--help] [--env]\n"
 125                                 "  --env    print the whole event environment\n"
 126                                 "  --help   print this help text\n\n");
 127                         exit(0);
 128                 } else {
 129                         fprintf(stderr, "unrecognized option '%s'\n", arg);
 130                         exit(1);
 131                 }
 132         }
 133
 134         if (getuid() != 0) {
 135                 fprintf(stderr, "root privileges required\n");
 136                 exit(2);
 137         }
 138
 139         /* set signal handlers */
 140         memset(&act, 0x00, sizeof(struct sigaction));
 141         act.sa_handler = (void (*)(int)) sig_handler;
 142         sigemptyset(&act.sa_mask);
 143         act.sa_flags = SA_RESTART;
 144         sigaction(SIGINT, &act, NULL);
 145         sigaction(SIGTERM, &act, NULL);
 146
 147         retval = init_udev_monitor_socket();
 148         if (retval)
 149                 goto out;
 150
 151         retval = init_uevent_netlink_sock();
 152         if (retval)
 153                 goto out;
 154
 155         printf("udevmonitor prints the received event from the kernel [UEVENT]\n"
 156                "and the event which udev sends out after rule processing [UDEV]\n\n");
 157
 158         while (!udev_exit) {
 159                 char buf[UEVENT_BUFFER_SIZE*2];
 160                 ssize_t buflen;
 161                 int fdcount;
 162                 struct timeval tv;
 163                 struct timezone tz;
 164                 char timestr[64];
 165
 166                 buflen = 0;
 167                 FD_ZERO(&readfds);
 168                 if (uevent_netlink_sock >= 0)
 169                         FD_SET(uevent_netlink_sock, &readfds);
 170                 if (udev_monitor_sock >= 0)
 171                         FD_SET(udev_monitor_sock, &readfds);
 172
 173                 fdcount = select(UDEV_MAX(uevent_netlink_sock, udev_monitor_sock)+1, &readfds, NULL, NULL, NULL);
 174                 if (fdcount < 0) {
 175                         if (errno != EINTR)
 176                                 fprintf(stderr, "error receiving uevent message: %s\n", strerror(errno));
 177                         continue;
 178                 }
 179
 180                 if (gettimeofday(&tv, &tz) == 0) {
 181                         snprintf(timestr, sizeof(timestr), "%llu.%06u",
 182                                  (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec);
 183                 } else
 184                         timestr[0] = '\0';
 185
 186                 if ((uevent_netlink_sock >= 0) && FD_ISSET(uevent_netlink_sock, &readfds)) {
 187                         buflen = recv(uevent_netlink_sock, &buf, sizeof(buf), 0);
 188                         if (buflen <=  0) {
 189                                 fprintf(stderr, "error receiving uevent message: %s\n", strerror(errno));
 190                                 continue;
 191                         }
 192                         printf("UEVENT[%s] %s\n", timestr, buf);
 193                 }
 194
 195                 if ((udev_monitor_sock >= 0) && FD_ISSET(udev_monitor_sock, &readfds)) {
 196                         buflen = recv(udev_monitor_sock, &buf, sizeof(buf), 0);
 197                         if (buflen <=  0) {
 198                                 fprintf(stderr, "error receiving udev message: %s\n", strerror(errno));
 199                                 continue;
 200                         }
 201                         printf("UDEV  [%s] %s\n", timestr, buf);
 202                 }
 203
 204                 if (buflen == 0)
 205                         continue;
 206
 207                 /* print environment */
 208                 if (env) {
 209                         size_t bufpos;
 210
 211                         /* start of payload */
 212                         bufpos = strlen(buf) + 1;
 213
 214                         while (bufpos < (size_t)buflen) {
 215                                 int keylen;
 216                                 char *key;
 217
 218                                 key = &buf[bufpos];
 219                                 keylen = strlen(key);
 220                                 if (keylen == 0)
 221                                         break;
 222                                 printf("%s\n", key);
 223                                 bufpos += keylen + 1;
 224                         }
 225                         printf("\n");
 226                 }
 227         }
 228
 229 out:
 230         if (uevent_netlink_sock >= 0)
 231                 close(uevent_netlink_sock);
 232         if (udev_monitor_sock >= 0)
 233                 close(udev_monitor_sock);
 234
 235         if (retval)
 236                 return 3;
 237         return 0;
 238 }