src/udev/udevadm-monitor.c

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  *
   4  */
   5
   6 #include <errno.h>
   7 #include <getopt.h>
   8 #include <signal.h>
   9 #include <stddef.h>
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <sys/epoll.h>
  13 #include <sys/time.h>
  14 #include <time.h>
  15
  16 #include "fd-util.h"
  17 #include "format-util.h"
  18 #include "udev-util.h"
  19 #include "udev.h"
  20 #include "udevadm-util.h"
  21
  22 static bool udev_exit;
  23
  24 static void sig_handler(int signum) {
  25         if (IN_SET(signum, SIGINT, SIGTERM))
  26                 udev_exit = true;
  27 }
  28
  29 static void print_device(struct udev_device *device, const char *source, int prop) {
  30         struct timespec ts;
  31
  32         assert_se(clock_gettime(CLOCK_MONOTONIC, &ts) == 0);
  33         printf("%-6s[%"PRI_TIME".%06"PRI_NSEC"] %-8s %s (%s)\n",
  34                source,
  35                ts.tv_sec, (nsec_t)ts.tv_nsec/1000,
  36                udev_device_get_action(device),
  37                udev_device_get_devpath(device),
  38                udev_device_get_subsystem(device));
  39         if (prop) {
  40                 struct udev_list_entry *list_entry;
  41
  42                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(device))
  43                         printf("%s=%s\n",
  44                                udev_list_entry_get_name(list_entry),
  45                                udev_list_entry_get_value(list_entry));
  46                 printf("\n");
  47         }
  48 }
  49
  50 static void help(void) {
  51         printf("%s monitor [OPTIONS]\n\n"
  52                "Listen to kernel and udev events.\n\n"
  53                "  -h --help                                Show this help\n"
  54                "  -V --version                             Show package version\n"
  55                "  -p --property                            Print the event properties\n"
  56                "  -k --kernel                              Print kernel uevents\n"
  57                "  -u --udev                                Print udev events\n"
  58                "  -s --subsystem-match=SUBSYSTEM[/DEVTYPE] Filter events by subsystem\n"
  59                "  -t --tag-match=TAG                       Filter events by tag\n"
  60                , program_invocation_short_name);
  61 }
  62
  63 static int adm_monitor(struct udev *udev, int argc, char *argv[]) {
  64         struct sigaction act = {};
  65         sigset_t mask;
  66         bool prop = false;
  67         bool print_kernel = false;
  68         bool print_udev = false;
  69         _cleanup_(udev_list_cleanup) struct udev_list subsystem_match_list;
  70         _cleanup_(udev_list_cleanup) struct udev_list tag_match_list;
  71         _cleanup_(udev_monitor_unrefp) struct udev_monitor *udev_monitor = NULL;
  72         _cleanup_(udev_monitor_unrefp) struct udev_monitor *kernel_monitor = NULL;
  73         _cleanup_close_ int fd_ep = -1;
  74         int fd_kernel = -1, fd_udev = -1;
  75         struct epoll_event ep_kernel, ep_udev;
  76         int c;
  77
  78         static const struct option options[] = {
  79                 { "property",        no_argument,       NULL, 'p' },
  80                 { "environment",     no_argument,       NULL, 'e' }, /* alias for -p */
  81                 { "kernel",          no_argument,       NULL, 'k' },
  82                 { "udev",            no_argument,       NULL, 'u' },
  83                 { "subsystem-match", required_argument, NULL, 's' },
  84                 { "tag-match",       required_argument, NULL, 't' },
  85                 { "version",         no_argument,       NULL, 'V' },
  86                 { "help",            no_argument,       NULL, 'h' },
  87                 {}
  88         };
  89
  90         udev_list_init(udev, &subsystem_match_list, true);
  91         udev_list_init(udev, &tag_match_list, true);
  92
  93         while ((c = getopt_long(argc, argv, "pekus:t:Vh", options, NULL)) >= 0)
  94                 switch (c) {
  95                 case 'p':
  96                 case 'e':
  97                         prop = true;
  98                         break;
  99                 case 'k':
 100                         print_kernel = true;
 101                         break;
 102                 case 'u':
 103                         print_udev = true;
 104                         break;
 105                 case 's':
 106                         {
 107                                 char subsys[UTIL_NAME_SIZE];
 108                                 char *devtype;
 109
 110                                 strscpy(subsys, sizeof(subsys), optarg);
 111                                 devtype = strchr(subsys, '/');
 112                                 if (devtype != NULL) {
 113                                         devtype[0] = '\0';
 114                                         devtype++;
 115                                 }
 116                                 udev_list_entry_add(&subsystem_match_list, subsys, devtype);
 117                                 break;
 118                         }
 119                 case 't':
 120                         udev_list_entry_add(&tag_match_list, optarg, NULL);
 121                         break;
 122                 case 'V':
 123                         print_version();
 124                         return 0;
 125                 case 'h':
 126                         help();
 127                         return 0;
 128                 default:
 129                         return 1;
 130                 }
 131
 132         if (!print_kernel && !print_udev) {
 133                 print_kernel = true;
 134                 print_udev = true;
 135         }
 136
 137         /* set signal handlers */
 138         act.sa_handler = sig_handler;
 139         act.sa_flags = SA_RESTART;
 140         assert_se(sigaction(SIGINT, &act, NULL) == 0);
 141         assert_se(sigaction(SIGTERM, &act, NULL) == 0);
 142         assert_se(sigemptyset(&mask) == 0);
 143         assert_se(sigaddset(&mask, SIGINT) == 0);
 144         assert_se(sigaddset(&mask, SIGTERM) == 0);
 145         assert_se(sigprocmask(SIG_UNBLOCK, &mask, NULL) == 0);
 146
 147         /* Callers are expecting to see events as they happen: Line buffering */
 148         setlinebuf(stdout);
 149
 150         fd_ep = epoll_create1(EPOLL_CLOEXEC);
 151         if (fd_ep < 0) {
 152                 log_error_errno(errno, "error creating epoll fd: %m");
 153                 return 1;
 154         }
 155
 156         printf("monitor will print the received events for:\n");
 157         if (print_udev) {
 158                 struct udev_list_entry *entry;
 159
 160                 udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
 161                 if (udev_monitor == NULL) {
 162                         fprintf(stderr, "error: unable to create netlink socket\n");
 163                         return 1;
 164                 }
 165                 udev_monitor_set_receive_buffer_size(udev_monitor, 128*1024*1024);
 166                 fd_udev = udev_monitor_get_fd(udev_monitor);
 167
 168                 udev_list_entry_foreach(entry, udev_list_get_entry(&subsystem_match_list)) {
 169                         const char *subsys = udev_list_entry_get_name(entry);
 170                         const char *devtype = udev_list_entry_get_value(entry);
 171
 172                         if (udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, subsys, devtype) < 0)
 173                                 fprintf(stderr, "error: unable to apply subsystem filter '%s'\n", subsys);
 174                 }
 175
 176                 udev_list_entry_foreach(entry, udev_list_get_entry(&tag_match_list)) {
 177                         const char *tag = udev_list_entry_get_name(entry);
 178
 179                         if (udev_monitor_filter_add_match_tag(udev_monitor, tag) < 0)
 180                                 fprintf(stderr, "error: unable to apply tag filter '%s'\n", tag);
 181                 }
 182
 183                 if (udev_monitor_enable_receiving(udev_monitor) < 0) {
 184                         fprintf(stderr, "error: unable to subscribe to udev events\n");
 185                         return 2;
 186                 }
 187
 188                 memzero(&ep_udev, sizeof(struct epoll_event));
 189                 ep_udev.events = EPOLLIN;
 190                 ep_udev.data.fd = fd_udev;
 191                 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_udev, &ep_udev) < 0) {
 192                         log_error_errno(errno, "fail to add fd to epoll: %m");
 193                         return 2;
 194                 }
 195
 196                 printf("UDEV - the event which udev sends out after rule processing\n");
 197         }
 198
 199         if (print_kernel) {
 200                 struct udev_list_entry *entry;
 201
 202                 kernel_monitor = udev_monitor_new_from_netlink(udev, "kernel");
 203                 if (kernel_monitor == NULL) {
 204                         fprintf(stderr, "error: unable to create netlink socket\n");
 205                         return 3;
 206                 }
 207                 udev_monitor_set_receive_buffer_size(kernel_monitor, 128*1024*1024);
 208                 fd_kernel = udev_monitor_get_fd(kernel_monitor);
 209
 210                 udev_list_entry_foreach(entry, udev_list_get_entry(&subsystem_match_list)) {
 211                         const char *subsys = udev_list_entry_get_name(entry);
 212
 213                         if (udev_monitor_filter_add_match_subsystem_devtype(kernel_monitor, subsys, NULL) < 0)
 214                                 fprintf(stderr, "error: unable to apply subsystem filter '%s'\n", subsys);
 215                 }
 216
 217                 if (udev_monitor_enable_receiving(kernel_monitor) < 0) {
 218                         fprintf(stderr, "error: unable to subscribe to kernel events\n");
 219                         return 4;
 220                 }
 221
 222                 memzero(&ep_kernel, sizeof(struct epoll_event));
 223                 ep_kernel.events = EPOLLIN;
 224                 ep_kernel.data.fd = fd_kernel;
 225                 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_kernel, &ep_kernel) < 0) {
 226                         log_error_errno(errno, "fail to add fd to epoll: %m");
 227                         return 5;
 228                 }
 229
 230                 printf("KERNEL - the kernel uevent\n");
 231         }
 232         printf("\n");
 233
 234         while (!udev_exit) {
 235                 int fdcount;
 236                 struct epoll_event ev[4];
 237                 int i;
 238
 239                 fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), -1);
 240                 if (fdcount < 0) {
 241                         if (errno != EINTR)
 242                                 fprintf(stderr, "error receiving uevent message: %m\n");
 243                         continue;
 244                 }
 245
 246                 for (i = 0; i < fdcount; i++) {
 247                         if (ev[i].data.fd == fd_kernel && ev[i].events & EPOLLIN) {
 248                                 struct udev_device *device;
 249
 250                                 device = udev_monitor_receive_device(kernel_monitor);
 251                                 if (device == NULL)
 252                                         continue;
 253                                 print_device(device, "KERNEL", prop);
 254                                 udev_device_unref(device);
 255                         } else if (ev[i].data.fd == fd_udev && ev[i].events & EPOLLIN) {
 256                                 struct udev_device *device;
 257
 258                                 device = udev_monitor_receive_device(udev_monitor);
 259                                 if (device == NULL)
 260                                         continue;
 261                                 print_device(device, "UDEV", prop);
 262                                 udev_device_unref(device);
 263                         }
 264                 }
 265         }
 266
 267         return 0;
 268 }
 269
 270 const struct udevadm_cmd udevadm_monitor = {
 271         .name = "monitor",
 272         .cmd = adm_monitor,
 273         .help = "Listen to kernel and udev events",
 274 };