udevmonitor.c

   1 /*
   2  * udevmonitor.c
   3  *
   4  * Copyright (C) 2004-2005 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 <string.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <signal.h>
  28 #include <sys/time.h>
  29 #include <sys/socket.h>
  30 #include <sys/un.h>
  31 #include <sys/select.h>
  32 #include <linux/types.h>
  33 #include <linux/netlink.h>
  34
  35 #include "udev.h"
  36 #include "udevd.h"
  37 #include "udev_utils.h"
  38 #include "udev_libc_wrapper.h"
  39
  40 static int uevent_netlink_sock;
  41 static int udev_monitor_sock;
  42 static volatile int udev_exit;
  43
  44 static int init_udev_monitor_socket(void)
  45 {
  46         struct sockaddr_un saddr;
  47         socklen_t addrlen;
  48         const int feature_on = 1;
  49         int retval;
  50
  51         memset(&saddr, 0x00, sizeof(saddr));
  52         saddr.sun_family = AF_LOCAL;
  53         /* use abstract namespace for socket path */
  54         strcpy(&saddr.sun_path[1], "/org/kernel/udev/monitor");
  55         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
  56
  57         udev_monitor_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  58         if (udev_monitor_sock == -1) {
  59                 fprintf(stderr, "error getting socket: %s\n", strerror(errno));
  60                 return -1;
  61         }
  62
  63         /* the bind takes care of ensuring only one copy running */
  64         retval = bind(udev_monitor_sock, (struct sockaddr *) &saddr, addrlen);
  65         if (retval < 0) {
  66                 fprintf(stderr, "bind failed: %s\n", strerror(errno));
  67                 close(udev_monitor_sock);
  68                 udev_monitor_sock = -1;
  69                 return -1;
  70         }
  71
  72         /* enable receiving of the sender credentials */
  73         setsockopt(udev_monitor_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
  74
  75         return 0;
  76 }
  77
  78 static int init_uevent_netlink_sock(void)
  79 {
  80         struct sockaddr_nl snl;
  81         int retval;
  82
  83         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
  84         snl.nl_family = AF_NETLINK;
  85         snl.nl_pid = getpid();
  86         snl.nl_groups = 0xffffffff;
  87
  88         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
  89         if (uevent_netlink_sock == -1) {
  90                 fprintf(stderr, "error getting socket: %s\n", strerror(errno));
  91                 return -1;
  92         }
  93
  94         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl,
  95                       sizeof(struct sockaddr_nl));
  96         if (retval < 0) {
  97                 fprintf(stderr, "bind failed: %s\n", strerror(errno));
  98                 close(uevent_netlink_sock);
  99                 uevent_netlink_sock = -1;
 100                 return -1;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static void asmlinkage sig_handler(int signum)
 107 {
 108         if (signum == SIGINT || signum == SIGTERM)
 109                 udev_exit = 1;
 110 }
 111
 112 int main(int argc, char *argv[])
 113 {
 114         struct sigaction act;
 115         int env = 0;
 116         fd_set readfds;
 117         int i;
 118         int retval = 0;
 119
 120         for (i = 1 ; i < argc; i++) {
 121                 char *arg = argv[i];
 122                 if (strcmp(arg, "--env") == 0 || strcmp(arg, "-e") == 0) {
 123                         env = 1;
 124                 }
 125                 else if (strcmp(arg, "--help") == 0  || strcmp(arg, "-h") == 0){
 126                         printf("Usage: udevmonitor [--env]\n"
 127                                 "  --env    print the whole event environment\n"
 128                                 "  --help   print this help text\n\n");
 129                         exit(0);
 130                 } else {
 131                         fprintf(stderr, "unknown option\n\n");
 132                         exit(1);
 133                 }
 134         }
 135
 136         if (getuid() != 0) {
 137                 fprintf(stderr, "need to be root, exit\n\n");
 138                 exit(2);
 139         }
 140
 141         /* set signal handlers */
 142         memset(&act, 0x00, sizeof(struct sigaction));
 143         act.sa_handler = (void (*)(int)) sig_handler;
 144         sigemptyset(&act.sa_mask);
 145         act.sa_flags = SA_RESTART;
 146         sigaction(SIGINT, &act, NULL);
 147         sigaction(SIGTERM, &act, NULL);
 148
 149         retval = init_udev_monitor_socket();
 150         if (retval)
 151                 goto out;
 152         retval = init_uevent_netlink_sock();
 153         if (retval)
 154                 goto out;
 155
 156         printf("udevmonitor prints the received event from the kernel [UEVENT]\n"
 157                "and the event which udev sends out after rule processing [UDEV]\n\n");
 158
 159         while (!udev_exit) {
 160                 static char buf[UEVENT_BUFFER_SIZE*2];
 161                 ssize_t buflen;
 162                 int fdcount;
 163                 struct timeval tv;
 164                 struct timezone tz;
 165                 char timestr[64];
 166
 167                 buflen = 0;
 168                 FD_ZERO(&readfds);
 169                 if (uevent_netlink_sock > 0)
 170                         FD_SET(uevent_netlink_sock, &readfds);
 171                 if (udev_monitor_sock > 0)
 172                         FD_SET(udev_monitor_sock, &readfds);
 173
 174                 fdcount = select(UDEV_MAX(uevent_netlink_sock, udev_monitor_sock)+1, &readfds, NULL, NULL, NULL);
 175                 if (fdcount < 0) {
 176                         if (errno != EINTR)
 177                                 fprintf(stderr, "error receiving uevent message: %s\n", strerror(errno));
 178                         continue;
 179                 }
 180
 181                 if (gettimeofday(&tv, &tz) == 0) {
 182                         snprintf(timestr, sizeof(timestr), "%llu.%06u",
 183                                  (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec);
 184                 } else
 185                         timestr[0] = '\0';
 186
 187                 if ((uevent_netlink_sock > 0) && FD_ISSET(uevent_netlink_sock, &readfds)) {
 188                         buflen = recv(uevent_netlink_sock, &buf, sizeof(buf), 0);
 189                         if (buflen <=  0) {
 190                                 fprintf(stderr, "error receiving uevent message: %s\n", strerror(errno));
 191                                 continue;
 192                         }
 193                         printf("UEVENT[%s] %s\n", timestr, buf);
 194                 }
 195
 196                 if ((udev_monitor_sock > 0) && FD_ISSET(udev_monitor_sock, &readfds)) {
 197                         buflen = recv(udev_monitor_sock, &buf, sizeof(buf), 0);
 198                         if (buflen <=  0) {
 199                                 fprintf(stderr, "error receiving udev message: %s\n", strerror(errno));
 200                                 continue;
 201                         }
 202                         printf("UDEV  [%s] %s\n", timestr, buf);
 203                 }
 204
 205                 if (buflen == 0)
 206                         continue;
 207
 208                 /* print environment */
 209                 if (env) {
 210                         size_t bufpos;
 211
 212                         /* start of payload */
 213                         bufpos = strlen(buf) + 1;
 214
 215                         while (bufpos < (size_t)buflen) {
 216                                 int keylen;
 217                                 char *key;
 218
 219                                 key = &buf[bufpos];
 220                                 keylen = strlen(key);
 221                                 if (keylen == 0)
 222                                         break;
 223                                 printf("%s\n", key);
 224                                 bufpos += keylen + 1;
 225                         }
 226                         printf("\n");
 227                 }
 228         }
 229
 230 out:
 231         if (uevent_netlink_sock > 0)
 232                 close(uevent_netlink_sock);
 233         if (udev_monitor_sock > 0)
 234                 close(udev_monitor_sock);
 235
 236         if (retval)
 237                 return 3;
 238         return 0;
 239 }