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 <getopt.h>
  27 #include <poll.h>
  28
  29 #include "udev.h"
  30 #include "util.h"
  31
  32 static void help(void) {
  33         printf("%s settle OPTIONS\n\n"
  34                "Wait for pending udev events.\n\n"
  35                "  -h --help                 Show this help\n"
  36                "     --version              Show package version\n"
  37                "  -t --timeout=SECONDS      Maximum time to wait for events\n"
  38                "  -E --exit-if-exists=FILE  Stop waiting if file exists\n"
  39                , program_invocation_short_name);
  40 }
  41
  42 static int adm_settle(struct udev *udev, int argc, char *argv[]) {
  43         static const struct option options[] = {
  44                 { "timeout",        required_argument, NULL, 't' },
  45                 { "exit-if-exists", required_argument, NULL, 'E' },
  46                 { "help",           no_argument,       NULL, 'h' },
  47                 { "seq-start",      required_argument, NULL, 's' }, /* removed */
  48                 { "seq-end",        required_argument, NULL, 'e' }, /* removed */
  49                 { "quiet",          no_argument,       NULL, 'q' }, /* removed */
  50                 {}
  51         };
  52         usec_t deadline;
  53         const char *exists = NULL;
  54         unsigned int timeout = 120;
  55         struct pollfd pfd[1] = { {.fd = -1}, };
  56         int c;
  57         struct udev_queue *queue;
  58         int rc = EXIT_FAILURE;
  59
  60         while ((c = getopt_long(argc, argv, "t:E:hs:e:q", options, NULL)) >= 0) {
  61                 switch (c) {
  62
  63                 case 't': {
  64                         int r;
  65
  66                         r = safe_atou(optarg, &timeout);
  67                         if (r < 0) {
  68                                 log_error_errno(r, "Invalid timeout value '%s': %m", optarg);
  69                                 return EXIT_FAILURE;
  70                         }
  71                         break;
  72                 }
  73
  74                 case 'E':
  75                         exists = optarg;
  76                         break;
  77
  78                 case 'h':
  79                         help();
  80                         return EXIT_SUCCESS;
  81
  82                 case 's':
  83                 case 'e':
  84                 case 'q':
  85                         log_info("Option -%c no longer supported.", c);
  86                         return EXIT_FAILURE;
  87
  88                 case '?':
  89                         return EXIT_FAILURE;
  90
  91                 default:
  92                         assert_not_reached("Unknown argument");
  93                 }
  94         }
  95
  96         if (optind < argc) {
  97                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
  98                 return EXIT_FAILURE;
  99         }
 100
 101         deadline = now(CLOCK_MONOTONIC) + timeout * USEC_PER_SEC;
 102
 103         /* guarantee that the udev daemon isn't pre-processing */
 104         if (getuid() == 0) {
 105                 struct udev_ctrl *uctrl;
 106
 107                 uctrl = udev_ctrl_new(udev);
 108                 if (uctrl != NULL) {
 109                         if (udev_ctrl_send_ping(uctrl, MAX(5U, timeout)) < 0) {
 110                                 log_debug("no connection to daemon");
 111                                 udev_ctrl_unref(uctrl);
 112                                 return EXIT_SUCCESS;
 113                         }
 114                         udev_ctrl_unref(uctrl);
 115                 }
 116         }
 117
 118         queue = udev_queue_new(udev);
 119         if (!queue) {
 120                 log_error("unable to get udev queue");
 121                 return EXIT_FAILURE;
 122         }
 123
 124         pfd[0].events = POLLIN;
 125         pfd[0].fd = udev_queue_get_fd(queue);
 126         if (pfd[0].fd < 0) {
 127                 log_debug("queue is empty, nothing to watch");
 128                 rc = EXIT_SUCCESS;
 129                 goto out;
 130         }
 131
 132         for (;;) {
 133                 if (exists && access(exists, F_OK) >= 0) {
 134                         rc = EXIT_SUCCESS;
 135                         break;
 136                 }
 137
 138                 /* exit if queue is empty */
 139                 if (udev_queue_get_queue_is_empty(queue)) {
 140                         rc = EXIT_SUCCESS;
 141                         break;
 142                 }
 143
 144                 if (now(CLOCK_MONOTONIC) >= deadline)
 145                         break;
 146
 147                 /* wake up when queue is empty */
 148                 if (poll(pfd, 1, MSEC_PER_SEC) > 0 && pfd[0].revents & POLLIN)
 149                         udev_queue_flush(queue);
 150         }
 151
 152 out:
 153         udev_queue_unref(queue);
 154         return rc;
 155 }
 156
 157 const struct udevadm_cmd udevadm_settle = {
 158         .name = "settle",
 159         .cmd = adm_settle,
 160         .help = "Wait for pending udev events",
 161 };