src/udev/udevadm-settle.c

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Copyright (C) 2006-2009 Kay Sievers <kay@vrfy.org>
   4  * Copyright (C) 2009 Canonical Ltd.
   5  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <errno.h>
  22 #include <getopt.h>
  23 #include <poll.h>
  24 #include <stddef.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29
  30 #include "parse-util.h"
  31 #include "udev.h"
  32 #include "udevadm-util.h"
  33 #include "util.h"
  34
  35 static void help(void) {
  36         printf("%s settle [OPTIONS]\n\n"
  37                "Wait for pending udev events.\n\n"
  38                "  -h --help                 Show this help\n"
  39                "  -V --version              Show package version\n"
  40                "  -t --timeout=SECONDS      Maximum time to wait for events\n"
  41                "  -E --exit-if-exists=FILE  Stop waiting if file exists\n"
  42                , program_invocation_short_name);
  43 }
  44
  45 static int adm_settle(struct udev *udev, int argc, char *argv[]) {
  46         static const struct option options[] = {
  47                 { "timeout",        required_argument, NULL, 't' },
  48                 { "exit-if-exists", required_argument, NULL, 'E' },
  49                 { "version",        no_argument,       NULL, 'V' },
  50                 { "help",           no_argument,       NULL, 'h' },
  51                 { "seq-start",      required_argument, NULL, 's' }, /* removed */
  52                 { "seq-end",        required_argument, NULL, 'e' }, /* removed */
  53                 { "quiet",          no_argument,       NULL, 'q' }, /* removed */
  54                 {}
  55         };
  56         usec_t deadline;
  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, "t:E:Vhs:e:q", options, NULL)) >= 0) {
  65                 switch (c) {
  66
  67                 case 't': {
  68                         int r;
  69
  70                         r = safe_atou(optarg, &timeout);
  71                         if (r < 0) {
  72                                 log_error_errno(r, "Invalid timeout value '%s': %m", optarg);
  73                                 return EXIT_FAILURE;
  74                         }
  75                         break;
  76                 }
  77
  78                 case 'E':
  79                         exists = optarg;
  80                         break;
  81
  82                 case 'V':
  83                         print_version();
  84                         return EXIT_SUCCESS;
  85
  86                 case 'h':
  87                         help();
  88                         return EXIT_SUCCESS;
  89
  90                 case 's':
  91                 case 'e':
  92                 case 'q':
  93                         log_info("Option -%c no longer supported.", c);
  94                         return EXIT_FAILURE;
  95
  96                 case '?':
  97                         return EXIT_FAILURE;
  98
  99                 default:
 100                         assert_not_reached("Unknown argument");
 101                 }
 102         }
 103
 104         if (optind < argc) {
 105                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
 106                 return EXIT_FAILURE;
 107         }
 108
 109         deadline = now(CLOCK_MONOTONIC) + timeout * USEC_PER_SEC;
 110
 111         /* guarantee that the udev daemon isn't pre-processing */
 112         if (getuid() == 0) {
 113                 struct udev_ctrl *uctrl;
 114
 115                 uctrl = udev_ctrl_new(udev);
 116                 if (uctrl != NULL) {
 117                         if (udev_ctrl_send_ping(uctrl, MAX(5U, timeout)) < 0) {
 118                                 log_debug("no connection to daemon");
 119                                 udev_ctrl_unref(uctrl);
 120                                 return EXIT_SUCCESS;
 121                         }
 122                         udev_ctrl_unref(uctrl);
 123                 }
 124         }
 125
 126         queue = udev_queue_new(udev);
 127         if (!queue) {
 128                 log_error("unable to get udev queue");
 129                 return EXIT_FAILURE;
 130         }
 131
 132         pfd[0].events = POLLIN;
 133         pfd[0].fd = udev_queue_get_fd(queue);
 134         if (pfd[0].fd < 0) {
 135                 log_debug("queue is empty, nothing to watch");
 136                 rc = EXIT_SUCCESS;
 137                 goto out;
 138         }
 139
 140         for (;;) {
 141                 if (exists && access(exists, F_OK) >= 0) {
 142                         rc = EXIT_SUCCESS;
 143                         break;
 144                 }
 145
 146                 /* exit if queue is empty */
 147                 if (udev_queue_get_queue_is_empty(queue)) {
 148                         rc = EXIT_SUCCESS;
 149                         break;
 150                 }
 151
 152                 if (now(CLOCK_MONOTONIC) >= deadline)
 153                         break;
 154
 155                 /* wake up when queue is empty */
 156                 if (poll(pfd, 1, MSEC_PER_SEC) > 0 && pfd[0].revents & POLLIN)
 157                         udev_queue_flush(queue);
 158         }
 159
 160 out:
 161         udev_queue_unref(queue);
 162         return rc;
 163 }
 164
 165 const struct udevadm_cmd udevadm_settle = {
 166         .name = "settle",
 167         .cmd = adm_settle,
 168         .help = "Wait for pending udev events",
 169 };