src/udev/udevadm-monitor.c

   1 /*
   2  * Copyright (C) 2004-2010 Kay Sievers <kay@vrfy.org>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <unistd.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <stddef.h>
  22 #include <string.h>
  23 #include <fcntl.h>
  24 #include <errno.h>
  25 #include <signal.h>
  26 #include <getopt.h>
  27 #include <time.h>
  28 #include <sys/time.h>
  29 #include <sys/socket.h>
  30 #include <sys/un.h>
  31 #include <sys/epoll.h>
  32 #include <linux/types.h>
  33 #include <linux/netlink.h>
  34
  35 #include "udev.h"
  36 #include "udev-util.h"
  37
  38 static bool udev_exit;
  39
  40 static void sig_handler(int signum)
  41 {
  42         if (signum == SIGINT || signum == SIGTERM)
  43                 udev_exit = true;
  44 }
  45
  46 static void print_device(struct udev_device *device, const char *source, int prop)
  47 {
  48         struct timespec ts;
  49
  50         clock_gettime(CLOCK_MONOTONIC, &ts);
  51         printf("%-6s[%llu.%06u] %-8s %s (%s)\n",
  52                source,
  53                (unsigned long long) ts.tv_sec, (unsigned int) ts.tv_nsec/1000,
  54                udev_device_get_action(device),
  55                udev_device_get_devpath(device),
  56                udev_device_get_subsystem(device));
  57         if (prop) {
  58                 struct udev_list_entry *list_entry;
  59
  60                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(device))
  61                         printf("%s=%s\n",
  62                                udev_list_entry_get_name(list_entry),
  63                                udev_list_entry_get_value(list_entry));
  64                 printf("\n");
  65         }
  66 }
  67
  68 static void help(void) {
  69         printf("Usage: udevadm monitor [--property] [--kernel] [--udev] [--help]\n"
  70                "  -p,--property                            print the event properties\n"
  71                "  -k,--kernel                              print kernel uevents\n"
  72                "  -u,--udev                                print udev events\n"
  73                "  -s,--subsystem-match=SUBSYSTEM[/DEVTYPE] filter events by subsystem\n"
  74                "  -t,--tag-match=TAG                       filter events by tag\n"
  75                "  -h,--help\n\n");
  76 }
  77
  78 static int adm_monitor(struct udev *udev, int argc, char *argv[])
  79 {
  80         struct sigaction act = {};
  81         sigset_t mask;
  82         bool prop = false;
  83         bool print_kernel = false;
  84         bool print_udev = false;
  85         _cleanup_udev_list_cleanup_ struct udev_list subsystem_match_list;
  86         _cleanup_udev_list_cleanup_ struct udev_list tag_match_list;
  87         _cleanup_udev_monitor_unref_ struct udev_monitor *udev_monitor = NULL;
  88         _cleanup_udev_monitor_unref_ struct udev_monitor *kernel_monitor = NULL;
  89         _cleanup_close_ int fd_ep = -1;
  90         int fd_kernel = -1, fd_udev = -1;
  91         struct epoll_event ep_kernel, ep_udev;
  92         int c;
  93
  94         static const struct option options[] = {
  95                 { "property",        no_argument,       NULL, 'p' },
  96                 { "environment",     no_argument,       NULL, 'e' }, /* alias for -p */
  97                 { "kernel",          no_argument,       NULL, 'k' },
  98                 { "udev",            no_argument,       NULL, 'u' },
  99                 { "subsystem-match", required_argument, NULL, 's' },
 100                 { "tag-match",       required_argument, NULL, 't' },
 101                 { "help",            no_argument,       NULL, 'h' },
 102                 {}
 103         };
 104
 105         udev_list_init(udev, &subsystem_match_list, true);
 106         udev_list_init(udev, &tag_match_list, true);
 107
 108         while((c = getopt_long(argc, argv, "pekus:t:h", options, NULL)) >= 0)
 109                 switch (c) {
 110                 case 'p':
 111                 case 'e':
 112                         prop = true;
 113                         break;
 114                 case 'k':
 115                         print_kernel = true;
 116                         break;
 117                 case 'u':
 118                         print_udev = true;
 119                         break;
 120                 case 's':
 121                         {
 122                                 char subsys[UTIL_NAME_SIZE];
 123                                 char *devtype;
 124
 125                                 strscpy(subsys, sizeof(subsys), optarg);
 126                                 devtype = strchr(subsys, '/');
 127                                 if (devtype != NULL) {
 128                                         devtype[0] = '\0';
 129                                         devtype++;
 130                                 }
 131                                 udev_list_entry_add(&subsystem_match_list, subsys, devtype);
 132                                 break;
 133                         }
 134                 case 't':
 135                         udev_list_entry_add(&tag_match_list, optarg, NULL);
 136                         break;
 137                 case 'h':
 138                         help();
 139                         return 0;
 140                 default:
 141                         return 1;
 142                 }
 143
 144         if (!print_kernel && !print_udev) {
 145                 print_kernel = true;
 146                 print_udev = true;
 147         }
 148
 149         /* set signal handlers */
 150         act.sa_handler = sig_handler;
 151         act.sa_flags = SA_RESTART;
 152         sigaction(SIGINT, &act, NULL);
 153         sigaction(SIGTERM, &act, NULL);
 154         sigemptyset(&mask);
 155         sigaddset(&mask, SIGINT);
 156         sigaddset(&mask, SIGTERM);
 157         sigprocmask(SIG_UNBLOCK, &mask, NULL);
 158
 159         fd_ep = epoll_create1(EPOLL_CLOEXEC);
 160         if (fd_ep < 0) {
 161                 log_error("error creating epoll fd: %m");
 162                 return 1;
 163         }
 164
 165         printf("monitor will print the received events for:\n");
 166         if (print_udev) {
 167                 struct udev_list_entry *entry;
 168
 169                 udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
 170                 if (udev_monitor == NULL) {
 171                         fprintf(stderr, "error: unable to create netlink socket\n");
 172                         return 1;
 173                 }
 174                 udev_monitor_set_receive_buffer_size(udev_monitor, 128*1024*1024);
 175                 fd_udev = udev_monitor_get_fd(udev_monitor);
 176
 177                 udev_list_entry_foreach(entry, udev_list_get_entry(&subsystem_match_list)) {
 178                         const char *subsys = udev_list_entry_get_name(entry);
 179                         const char *devtype = udev_list_entry_get_value(entry);
 180
 181                         if (udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, subsys, devtype) < 0)
 182                                 fprintf(stderr, "error: unable to apply subsystem filter '%s'\n", subsys);
 183                 }
 184
 185                 udev_list_entry_foreach(entry, udev_list_get_entry(&tag_match_list)) {
 186                         const char *tag = udev_list_entry_get_name(entry);
 187
 188                         if (udev_monitor_filter_add_match_tag(udev_monitor, tag) < 0)
 189                                 fprintf(stderr, "error: unable to apply tag filter '%s'\n", tag);
 190                 }
 191
 192                 if (udev_monitor_enable_receiving(udev_monitor) < 0) {
 193                         fprintf(stderr, "error: unable to subscribe to udev events\n");
 194                         return 2;
 195                 }
 196
 197                 memzero(&ep_udev, sizeof(struct epoll_event));
 198                 ep_udev.events = EPOLLIN;
 199                 ep_udev.data.fd = fd_udev;
 200                 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_udev, &ep_udev) < 0) {
 201                         log_error("fail to add fd to epoll: %m");
 202                         return 2;
 203                 }
 204
 205                 printf("UDEV - the event which udev sends out after rule processing\n");
 206         }
 207
 208         if (print_kernel) {
 209                 struct udev_list_entry *entry;
 210
 211                 kernel_monitor = udev_monitor_new_from_netlink(udev, "kernel");
 212                 if (kernel_monitor == NULL) {
 213                         fprintf(stderr, "error: unable to create netlink socket\n");
 214                         return 3;
 215                 }
 216                 udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 217                 fd_kernel = udev_monitor_get_fd(kernel_monitor);
 218
 219                 udev_list_entry_foreach(entry, udev_list_get_entry(&subsystem_match_list)) {
 220                         const char *subsys = udev_list_entry_get_name(entry);
 221
 222                         if (udev_monitor_filter_add_match_subsystem_devtype(kernel_monitor, subsys, NULL) < 0)
 223                                 fprintf(stderr, "error: unable to apply subsystem filter '%s'\n", subsys);
 224                 }
 225
 226                 if (udev_monitor_enable_receiving(kernel_monitor) < 0) {
 227                         fprintf(stderr, "error: unable to subscribe to kernel events\n");
 228                         return 4;
 229                 }
 230
 231                 memzero(&ep_kernel, sizeof(struct epoll_event));
 232                 ep_kernel.events = EPOLLIN;
 233                 ep_kernel.data.fd = fd_kernel;
 234                 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_kernel, &ep_kernel) < 0) {
 235                         log_error("fail to add fd to epoll: %m");
 236                         return 5;
 237                 }
 238
 239                 printf("KERNEL - the kernel uevent\n");
 240         }
 241         printf("\n");
 242
 243         while (!udev_exit) {
 244                 int fdcount;
 245                 struct epoll_event ev[4];
 246                 int i;
 247
 248                 fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), -1);
 249                 if (fdcount < 0) {
 250                         if (errno != EINTR)
 251                                 fprintf(stderr, "error receiving uevent message: %m\n");
 252                         continue;
 253                 }
 254
 255                 for (i = 0; i < fdcount; i++) {
 256                         if (ev[i].data.fd == fd_kernel && ev[i].events & EPOLLIN) {
 257                                 struct udev_device *device;
 258
 259                                 device = udev_monitor_receive_device(kernel_monitor);
 260                                 if (device == NULL)
 261                                         continue;
 262                                 print_device(device, "KERNEL", prop);
 263                                 udev_device_unref(device);
 264                         } else if (ev[i].data.fd == fd_udev && ev[i].events & EPOLLIN) {
 265                                 struct udev_device *device;
 266
 267                                 device = udev_monitor_receive_device(udev_monitor);
 268                                 if (device == NULL)
 269                                         continue;
 270                                 print_device(device, "UDEV", prop);
 271                                 udev_device_unref(device);
 272                         }
 273                 }
 274         }
 275
 276         return 0;
 277 }
 278
 279 const struct udevadm_cmd udevadm_monitor = {
 280         .name = "monitor",
 281         .cmd = adm_monitor,
 282         .help = "listen to kernel and udev events",
 283 };