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