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