udev/udevadm-settle.c

   1 /*
   2  * Copyright (C) 2006 Kay Sievers <kay@vrfy.org>
   3  *
   4  *      This program is free software; you can redistribute it and/or modify it
   5  *      under the terms of the GNU General Public License as published by the
   6  *      Free Software Foundation version 2 of the License.
   7  *
   8  *      This program is distributed in the hope that it will be useful, but
   9  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  *      General Public License for more details.
  12  *
  13  *      You should have received a copy of the GNU General Public License along
  14  *      with this program; if not, write to the Free Software Foundation, Inc.,
  15  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  16  *
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stddef.h>
  21 #include <string.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <dirent.h>
  26 #include <fcntl.h>
  27 #include <syslog.h>
  28 #include <getopt.h>
  29 #include <sys/stat.h>
  30 #include <sys/types.h>
  31
  32 #include "udev.h"
  33
  34 #define DEFAULT_TIMEOUT                 180
  35 #define LOOP_PER_SECOND                 20
  36
  37 static void print_queue(struct udev *udev, const char *dir)
  38 {
  39         LIST_HEAD(files);
  40         struct name_entry *item;
  41
  42         if (add_matching_files(udev, &files, dir, NULL) < 0)
  43                 return;
  44
  45         printf("\n\nAfter the udevadm settle timeout, the events queue contains:\n\n");
  46
  47         list_for_each_entry(item, &files, node) {
  48                 char target[NAME_SIZE];
  49                 size_t len;
  50                 const char *filename = strrchr(item->name, '/');
  51
  52                 if (filename == NULL)
  53                         continue;
  54                 filename++;
  55                 if (*filename == '\0')
  56                         continue;
  57
  58                 len = readlink(item->name, target, sizeof(target));
  59                 if (len < 0)
  60                         continue;
  61                 target[len] = '\0';
  62
  63                 printf("%s: %s\n", filename, target);
  64         }
  65
  66         printf("\n\n");
  67 }
  68
  69 int udevadm_settle(struct udev *udev, int argc, char *argv[])
  70 {
  71         char queuename[PATH_SIZE];
  72         char filename[PATH_SIZE];
  73         unsigned long long seq_kernel;
  74         unsigned long long seq_udev;
  75         char seqnum[32];
  76         int fd;
  77         ssize_t len;
  78         int timeout = DEFAULT_TIMEOUT;
  79         int loop;
  80         static const struct option options[] = {
  81                 { "timeout", 1, NULL, 't' },
  82                 { "help", 0, NULL, 'h' },
  83                 {}
  84         };
  85         int option;
  86         int rc = 1;
  87         int seconds;
  88
  89         dbg(udev, "version %s\n", VERSION);
  90
  91         while (1) {
  92                 option = getopt_long(argc, argv, "t:h", options, NULL);
  93                 if (option == -1)
  94                         break;
  95
  96                 switch (option) {
  97                 case 't':
  98                         seconds = atoi(optarg);
  99                         if (seconds > 0)
 100                                 timeout = seconds;
 101                         else
 102                                 fprintf(stderr, "invalid timeout value\n");
 103                         dbg(udev, "timeout=%i\n", timeout);
 104                         break;
 105                 case 'h':
 106                         printf("Usage: udevadm settle [--help] [--timeout=<seconds>]\n\n");
 107                         goto exit;
 108                 }
 109         }
 110
 111         strlcpy(queuename, udev_get_dev_path(udev), sizeof(queuename));
 112         strlcat(queuename, "/.udev/queue", sizeof(queuename));
 113
 114         loop = timeout * LOOP_PER_SECOND;
 115         while (loop--) {
 116                 /* wait for events in queue to finish */
 117                 while (loop--) {
 118                         struct stat statbuf;
 119
 120                         if (stat(queuename, &statbuf) < 0) {
 121                                 info(udev, "queue is empty\n");
 122                                 break;
 123                         }
 124                         usleep(1000 * 1000 / LOOP_PER_SECOND);
 125                 }
 126                 if (loop <= 0) {
 127                         info(udev, "timeout waiting for queue\n");
 128                         print_queue(udev, queuename);
 129                         goto exit;
 130                 }
 131
 132                 /* read current udev seqnum */
 133                 strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 134                 strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 135                 fd = open(filename, O_RDONLY);
 136                 if (fd < 0)
 137                         goto exit;
 138                 len = read(fd, seqnum, sizeof(seqnum)-1);
 139                 close(fd);
 140                 if (len <= 0)
 141                         goto exit;
 142                 seqnum[len] = '\0';
 143                 seq_udev = strtoull(seqnum, NULL, 10);
 144                 info(udev, "udev seqnum = %llu\n", seq_udev);
 145
 146                 /* read current kernel seqnum */
 147                 strlcpy(filename, udev_get_sys_path(udev), sizeof(filename));
 148                 strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 149                 fd = open(filename, O_RDONLY);
 150                 if (fd < 0)
 151                         goto exit;
 152                 len = read(fd, seqnum, sizeof(seqnum)-1);
 153                 close(fd);
 154                 if (len <= 0)
 155                         goto exit;
 156                 seqnum[len] = '\0';
 157                 seq_kernel = strtoull(seqnum, NULL, 10);
 158                 info(udev, "kernel seqnum = %llu\n", seq_kernel);
 159
 160                 /* make sure all kernel events have arrived in the queue */
 161                 if (seq_udev >= seq_kernel) {
 162                         info(udev, "queue is empty and no pending events left\n");
 163                         rc = 0;
 164                         goto exit;
 165                 }
 166                 usleep(1000 * 1000 / LOOP_PER_SECOND);
 167                 info(udev, "queue is empty, but events still pending\n");
 168         }
 169
 170 exit:
 171         return rc;
 172 }