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 <getopt.h>
  29 #include <signal.h>
  30 #include <time.h>
  31 #include <sys/poll.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34
  35 #include "udev.h"
  36 #include "udev-util.h"
  37 #include "util.h"
  38
  39 static void help(void) {
  40         printf("%s settle OPTIONS\n\n"
  41                "Wait for pending udev events.\n\n"
  42                "  -h --help                 Show this help\n"
  43                "     --version              Show package version\n"
  44                "  -t --timeout=SECONDS      Maximum time to wait for events\n"
  45                "  -E --exit-if-exists=FILE  Stop waiting if file exists\n"
  46                , program_invocation_short_name);
  47 }
  48
  49 static int adm_settle(struct udev *udev, int argc, char *argv[]) {
  50         static const struct option options[] = {
  51                 { "seq-start",      required_argument, NULL, '\0' }, /* removed */
  52                 { "seq-end",        required_argument, NULL, '\0' }, /* removed */
  53                 { "timeout",        required_argument, NULL, 't' },
  54                 { "exit-if-exists", required_argument, NULL, 'E' },
  55                 { "quiet",          no_argument,       NULL, 'q' },  /* removed */
  56                 { "help",           no_argument,       NULL, 'h' },
  57                 {}
  58         };
  59         const char *exists = NULL;
  60         unsigned int timeout = 120;
  61         struct pollfd pfd[1] = { {.fd = -1}, };
  62         int c;
  63         struct udev_queue *queue;
  64         int rc = EXIT_FAILURE;
  65
  66         while ((c = getopt_long(argc, argv, "s:e:t:E:qh", options, NULL)) >= 0) {
  67                 switch (c) {
  68                 case 't': {
  69                         int r;
  70
  71                         r = safe_atou(optarg, &timeout);
  72                         if (r < 0) {
  73                                 fprintf(stderr, "Invalid timeout value '%s': %s\n",
  74                                         optarg, strerror(-r));
  75                                 exit(EXIT_FAILURE);
  76                         };
  77                         break;
  78                 }
  79                 case 'E':
  80                         exists = optarg;
  81                         break;
  82                 case 'h':
  83                         help();
  84                         return EXIT_SUCCESS;
  85                 case '?':
  86                         return EXIT_FAILURE;
  87                 default:
  88                         assert_not_reached("Unknown argument");
  89                 }
  90         }
  91
  92         if (optind < argc) {
  93                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
  94                 return EXIT_FAILURE;
  95         }
  96
  97         /* guarantee that the udev daemon isn't pre-processing */
  98         if (getuid() == 0) {
  99                 struct udev_ctrl *uctrl;
 100
 101                 uctrl = udev_ctrl_new(udev);
 102                 if (uctrl != NULL) {
 103                         if (udev_ctrl_send_ping(uctrl, timeout) < 0) {
 104                                 log_debug("no connection to daemon");
 105                                 udev_ctrl_unref(uctrl);
 106                                 return EXIT_SUCCESS;
 107                         }
 108                         udev_ctrl_unref(uctrl);
 109                 }
 110         }
 111
 112         queue = udev_queue_new(udev);
 113         if (!queue) {
 114                 log_error("unable to get udev queue");
 115                 return EXIT_FAILURE;
 116         }
 117
 118         pfd[0].events = POLLIN;
 119         pfd[0].fd = udev_queue_get_fd(queue);
 120         if (pfd[0].fd < 0) {
 121                 log_debug("queue is empty, nothing to watch");
 122                 rc = EXIT_SUCCESS;
 123                 goto out;
 124         }
 125
 126         for (;;) {
 127                 if (exists && access(exists, F_OK) >= 0) {
 128                         rc = EXIT_SUCCESS;
 129                         break;
 130                 }
 131
 132                 /* exit if queue is empty */
 133                 if (udev_queue_get_queue_is_empty(queue)) {
 134                         rc = EXIT_SUCCESS;
 135                         break;
 136                 }
 137
 138                 /* wake up when queue is empty */
 139                 if (poll(pfd, 1, MSEC_PER_SEC) > 0 && pfd[0].revents & POLLIN)
 140                         udev_queue_flush(queue);
 141         }
 142
 143 out:
 144         udev_queue_unref(queue);
 145         return rc;
 146 }
 147
 148 const struct udevadm_cmd udevadm_settle = {
 149         .name = "settle",
 150         .cmd = adm_settle,
 151         .help = "Wait for pending udev events",
 152 };