src/udev/udevadm-settle.c

   1 /*
   2  * Copyright (C) 2006-2009 Kay Sievers <kay@vrfy.org>
   3  * Copyright (C) 2009 Canonical Ltd.
   4  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdlib.h>
  21 #include <stddef.h>
  22 #include <string.h>
  23 #include <stdio.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <dirent.h>
  27 #include <fcntl.h>
  28 #include <syslog.h>
  29 #include <getopt.h>
  30 #include <signal.h>
  31 #include <time.h>
  32 #include <sys/poll.h>
  33 #include <sys/stat.h>
  34 #include <sys/types.h>
  35
  36 #include "udev.h"
  37 #include "udev-util.h"
  38 #include "util.h"
  39
  40 static void help(void) {
  41         printf("Usage: udevadm settle OPTIONS\n"
  42                "  -t,--timeout=<seconds>     maximum time to wait for events\n"
  43                "  -E,--exit-if-exists=<file> stop waiting if file exists\n"
  44                "  -h,--help\n\n");
  45 }
  46
  47 static int adm_settle(struct udev *udev, int argc, char *argv[])
  48 {
  49         static const struct option options[] = {
  50                 { "seq-start",      required_argument, NULL, '\0' }, /* removed */
  51                 { "seq-end",        required_argument, NULL, '\0' }, /* removed */
  52                 { "timeout",        required_argument, NULL, 't' },
  53                 { "exit-if-exists", required_argument, NULL, 'E' },
  54                 { "quiet",          no_argument,       NULL, 'q' },  /* removed */
  55                 { "help",           no_argument,       NULL, 'h' },
  56                 {}
  57         };
  58         const char *exists = NULL;
  59         unsigned int timeout = 120;
  60         struct pollfd pfd[1] = { {.fd = -1}, };
  61         int c;
  62         struct udev_queue *queue;
  63         int rc = EXIT_FAILURE;
  64
  65         while ((c = getopt_long(argc, argv, "s:e:t:E:qh", options, NULL)) >= 0) {
  66                 switch (c) {
  67                 case 't': {
  68                         int r;
  69
  70                         r = safe_atou(optarg, &timeout);
  71                         if (r < 0) {
  72                                 fprintf(stderr, "Invalid timeout value '%s': %s\n",
  73                                         optarg, strerror(-r));
  74                                 exit(EXIT_FAILURE);
  75                         };
  76                         break;
  77                 }
  78                 case 'E':
  79                         exists = optarg;
  80                         break;
  81                 case 'h':
  82                         help();
  83                         return EXIT_SUCCESS;
  84                 case '?':
  85                         return EXIT_FAILURE;
  86                 default:
  87                         assert_not_reached("Unknown argument");
  88                 }
  89         }
  90
  91         if (optind < argc) {
  92                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
  93                 return EXIT_FAILURE;
  94         }
  95
  96         /* guarantee that the udev daemon isn't pre-processing */
  97         if (getuid() == 0) {
  98                 struct udev_ctrl *uctrl;
  99
 100                 uctrl = udev_ctrl_new(udev);
 101                 if (uctrl != NULL) {
 102                         if (udev_ctrl_send_ping(uctrl, timeout) < 0) {
 103                                 log_debug("no connection to daemon");
 104                                 udev_ctrl_unref(uctrl);
 105                                 return EXIT_SUCCESS;
 106                         }
 107                         udev_ctrl_unref(uctrl);
 108                 }
 109         }
 110
 111         queue = udev_queue_new(udev);
 112         if (!queue) {
 113                 log_error("unable to get udev queue");
 114                 return EXIT_FAILURE;
 115         }
 116
 117         pfd[0].events = POLLIN;
 118         pfd[0].fd = udev_queue_get_fd(queue);
 119         if (pfd[0].fd < 0) {
 120                 log_debug("queue is empty, nothing to watch");
 121                 rc = EXIT_SUCCESS;
 122                 goto out;
 123         }
 124
 125         for (;;) {
 126                 if (exists && access(exists, F_OK) >= 0) {
 127                         rc = EXIT_SUCCESS;
 128                         break;
 129                 }
 130
 131                 /* exit if queue is empty */
 132                 if (udev_queue_get_queue_is_empty(queue)) {
 133                         rc = EXIT_SUCCESS;
 134                         break;
 135                 }
 136
 137                 /* wake up when queue is empty */
 138                 if (poll(pfd, 1, MSEC_PER_SEC) > 0 && pfd[0].revents & POLLIN)
 139                         udev_queue_flush(queue);
 140         }
 141
 142 out:
 143         udev_queue_unref(queue);
 144         return rc;
 145 }
 146
 147 const struct udevadm_cmd udevadm_settle = {
 148         .name = "settle",
 149         .cmd = adm_settle,
 150         .help = "wait for pending udev events",
 151 };