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         if (signum == SIGINT || signum == SIGTERM)
  42                 udev_exit = true;
  43 }
  44
  45 static void print_device(struct udev_device *device, const char *source, int prop) {
  46         struct timespec ts;
  47
  48         clock_gettime(CLOCK_MONOTONIC, &ts);
  49         printf("%-6s[%"PRI_TIME".%06ld] %-8s %s (%s)\n",
  50                source,
  51                ts.tv_sec, ts.tv_nsec/1000,
  52                udev_device_get_action(device),
  53                udev_device_get_devpath(device),
  54                udev_device_get_subsystem(device));
  55         if (prop) {
  56                 struct udev_list_entry *list_entry;
  57
  58                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(device))
  59                         printf("%s=%s\n",
  60                                udev_list_entry_get_name(list_entry),
  61                                udev_list_entry_get_value(list_entry));
  62                 printf("\n");
  63         }
  64 }
  65
  66 static void help(void) {
  67         printf("Usage: udevadm monitor [--property] [--kernel] [--udev] [--help]\n"
  68                "  -p,--property                            print the event properties\n"
  69                "  -k,--kernel                              print kernel uevents\n"
  70                "  -u,--udev                                print udev events\n"
  71                "  -s,--subsystem-match=SUBSYSTEM[/DEVTYPE] filter events by subsystem\n"
  72                "  -t,--tag-match=TAG                       filter events by tag\n"
  73                "  -h,--help\n\n");
  74 }
  75
  76 static int adm_monitor(struct udev *udev, int argc, char *argv[]) {
  77         struct sigaction act = {};
  78         sigset_t mask;
  79         bool prop = false;
  80         bool print_kernel = false;
  81         bool print_udev = false;
  82         _cleanup_udev_list_cleanup_ struct udev_list subsystem_match_list;
  83         _cleanup_udev_list_cleanup_ struct udev_list tag_match_list;
  84         _cleanup_udev_monitor_unref_ struct udev_monitor *udev_monitor = NULL;
  85         _cleanup_udev_monitor_unref_ struct udev_monitor *kernel_monitor = NULL;
  86         _cleanup_close_ int fd_ep = -1;
  87         int fd_kernel = -1, fd_udev = -1;
  88         struct epoll_event ep_kernel, ep_udev;
  89         int c;
  90
  91         static const struct option options[] = {
  92                 { "property",        no_argument,       NULL, 'p' },
  93                 { "environment",     no_argument,       NULL, 'e' }, /* alias for -p */
  94                 { "kernel",          no_argument,       NULL, 'k' },
  95                 { "udev",            no_argument,       NULL, 'u' },
  96                 { "subsystem-match", required_argument, NULL, 's' },
  97                 { "tag-match",       required_argument, NULL, 't' },
  98                 { "help",            no_argument,       NULL, 'h' },
  99                 {}
 100         };
 101
 102         udev_list_init(udev, &subsystem_match_list, true);
 103         udev_list_init(udev, &tag_match_list, true);
 104
 105         while((c = getopt_long(argc, argv, "pekus:t:h", options, NULL)) >= 0)
 106                 switch (c) {
 107                 case 'p':
 108                 case 'e':
 109                         prop = true;
 110                         break;
 111                 case 'k':
 112                         print_kernel = true;
 113                         break;
 114                 case 'u':
 115                         print_udev = true;
 116                         break;
 117                 case 's':
 118                         {
 119                                 char subsys[UTIL_NAME_SIZE];
 120                                 char *devtype;
 121
 122                                 strscpy(subsys, sizeof(subsys), optarg);
 123                                 devtype = strchr(subsys, '/');
 124                                 if (devtype != NULL) {
 125                                         devtype[0] = '\0';
 126                                         devtype++;
 127                                 }
 128                                 udev_list_entry_add(&subsystem_match_list, subsys, devtype);
 129                                 break;
 130                         }
 131                 case 't':
 132                         udev_list_entry_add(&tag_match_list, optarg, NULL);
 133                         break;
 134                 case 'h':
 135                         help();
 136                         return 0;
 137                 default:
 138                         return 1;
 139                 }
 140
 141         if (!print_kernel && !print_udev) {
 142                 print_kernel = true;
 143                 print_udev = true;
 144         }
 145
 146         /* set signal handlers */
 147         act.sa_handler = sig_handler;
 148         act.sa_flags = SA_RESTART;
 149         sigaction(SIGINT, &act, NULL);
 150         sigaction(SIGTERM, &act, NULL);
 151         sigemptyset(&mask);
 152         sigaddset(&mask, SIGINT);
 153         sigaddset(&mask, SIGTERM);
 154         sigprocmask(SIG_UNBLOCK, &mask, NULL);
 155
 156         fd_ep = epoll_create1(EPOLL_CLOEXEC);
 157         if (fd_ep < 0) {
 158                 log_error_errno(errno, "error creating epoll fd: %m");
 159                 return 1;
 160         }
 161
 162         printf("monitor will print the received events for:\n");
 163         if (print_udev) {
 164                 struct udev_list_entry *entry;
 165
 166                 udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
 167                 if (udev_monitor == NULL) {
 168                         fprintf(stderr, "error: unable to create netlink socket\n");
 169                         return 1;
 170                 }
 171                 udev_monitor_set_receive_buffer_size(udev_monitor, 128*1024*1024);
 172                 fd_udev = udev_monitor_get_fd(udev_monitor);
 173
 174                 udev_list_entry_foreach(entry, udev_list_get_entry(&subsystem_match_list)) {
 175                         const char *subsys = udev_list_entry_get_name(entry);
 176                         const char *devtype = udev_list_entry_get_value(entry);
 177
 178                         if (udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, subsys, devtype) < 0)
 179                                 fprintf(stderr, "error: unable to apply subsystem filter '%s'\n", subsys);
 180                 }
 181
 182                 udev_list_entry_foreach(entry, udev_list_get_entry(&tag_match_list)) {
 183                         const char *tag = udev_list_entry_get_name(entry);
 184
 185                         if (udev_monitor_filter_add_match_tag(udev_monitor, tag) < 0)
 186                                 fprintf(stderr, "error: unable to apply tag filter '%s'\n", tag);
 187                 }
 188
 189                 if (udev_monitor_enable_receiving(udev_monitor) < 0) {
 190                         fprintf(stderr, "error: unable to subscribe to udev events\n");
 191                         return 2;
 192                 }
 193
 194                 memzero(&ep_udev, sizeof(struct epoll_event));
 195                 ep_udev.events = EPOLLIN;
 196                 ep_udev.data.fd = fd_udev;
 197                 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_udev, &ep_udev) < 0) {
 198                         log_error_errno(errno, "fail to add fd to epoll: %m");
 199                         return 2;
 200                 }
 201
 202                 printf("UDEV - the event which udev sends out after rule processing\n");
 203         }
 204
 205         if (print_kernel) {
 206                 struct udev_list_entry *entry;
 207
 208                 kernel_monitor = udev_monitor_new_from_netlink(udev, "kernel");
 209                 if (kernel_monitor == NULL) {
 210                         fprintf(stderr, "error: unable to create netlink socket\n");
 211                         return 3;
 212                 }
 213                 udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 214                 fd_kernel = udev_monitor_get_fd(kernel_monitor);
 215
 216                 udev_list_entry_foreach(entry, udev_list_get_entry(&subsystem_match_list)) {
 217                         const char *subsys = udev_list_entry_get_name(entry);
 218
 219                         if (udev_monitor_filter_add_match_subsystem_devtype(kernel_monitor, subsys, NULL) < 0)
 220                                 fprintf(stderr, "error: unable to apply subsystem filter '%s'\n", subsys);
 221                 }
 222
 223                 if (udev_monitor_enable_receiving(kernel_monitor) < 0) {
 224                         fprintf(stderr, "error: unable to subscribe to kernel events\n");
 225                         return 4;
 226                 }
 227
 228                 memzero(&ep_kernel, sizeof(struct epoll_event));
 229                 ep_kernel.events = EPOLLIN;
 230                 ep_kernel.data.fd = fd_kernel;
 231                 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_kernel, &ep_kernel) < 0) {
 232                         log_error_errno(errno, "fail to add fd to epoll: %m");
 233                         return 5;
 234                 }
 235
 236                 printf("KERNEL - the kernel uevent\n");
 237         }
 238         printf("\n");
 239
 240         while (!udev_exit) {
 241                 int fdcount;
 242                 struct epoll_event ev[4];
 243                 int i;
 244
 245                 fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), -1);
 246                 if (fdcount < 0) {
 247                         if (errno != EINTR)
 248                                 fprintf(stderr, "error receiving uevent message: %m\n");
 249                         continue;
 250                 }
 251
 252                 for (i = 0; i < fdcount; i++) {
 253                         if (ev[i].data.fd == fd_kernel && ev[i].events & EPOLLIN) {
 254                                 struct udev_device *device;
 255
 256                                 device = udev_monitor_receive_device(kernel_monitor);
 257                                 if (device == NULL)
 258                                         continue;
 259                                 print_device(device, "KERNEL", prop);
 260                                 udev_device_unref(device);
 261                         } else if (ev[i].data.fd == fd_udev && ev[i].events & EPOLLIN) {
 262                                 struct udev_device *device;
 263
 264                                 device = udev_monitor_receive_device(udev_monitor);
 265                                 if (device == NULL)
 266                                         continue;
 267                                 print_device(device, "UDEV", prop);
 268                                 udev_device_unref(device);
 269                         }
 270                 }
 271         }
 272
 273         return 0;
 274 }
 275
 276 const struct udevadm_cmd udevadm_monitor = {
 277         .name = "monitor",
 278         .cmd = adm_monitor,
 279         .help = "listen to kernel and udev events",
 280 };