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