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 #include "udevd.h"
  34
  35 #define DEFAULT_TIMEOUT                 180
  36 #define LOOP_PER_SECOND                 20
  37
  38 static void print_queue(const char *dir)
  39 {
  40         LIST_HEAD(files);
  41         struct name_entry *item;
  42
  43         if (add_matching_files(&files, dir, NULL) < 0)
  44                 return;
  45
  46         printf("\n\nAfter the udevadm settle timeout, the events queue contains:\n\n");
  47
  48         list_for_each_entry(item, &files, node) {
  49                 char target[NAME_SIZE];
  50                 size_t len;
  51                 const char *filename = strrchr(item->name, '/');
  52
  53                 if (filename == NULL)
  54                         continue;
  55                 filename++;
  56                 if (*filename == '\0')
  57                         continue;
  58
  59                 len = readlink(item->name, target, sizeof(target));
  60                 if (len < 0)
  61                         continue;
  62                 target[len] = '\0';
  63
  64                 printf("%s: %s\n", filename, target);
  65         }
  66
  67         printf("\n\n");
  68 }
  69
  70 int udevadm_settle(int argc, char *argv[])
  71 {
  72         char queuename[PATH_SIZE];
  73         char filename[PATH_SIZE];
  74         unsigned long long seq_kernel;
  75         unsigned long long seq_udev;
  76         char seqnum[32];
  77         int fd;
  78         ssize_t len;
  79         int timeout = DEFAULT_TIMEOUT;
  80         int loop;
  81         static const struct option options[] = {
  82                 { "timeout", 1, NULL, 't' },
  83                 { "help", 0, NULL, 'h' },
  84                 {}
  85         };
  86         int option;
  87         int rc = 1;
  88         int seconds;
  89
  90         dbg("version %s\n", VERSION);
  91
  92         while (1) {
  93                 option = getopt_long(argc, argv, "t:h", options, NULL);
  94                 if (option == -1)
  95                         break;
  96
  97                 switch (option) {
  98                 case 't':
  99                         seconds = atoi(optarg);
 100                         if (seconds > 0)
 101                                 timeout = seconds;
 102                         else
 103                                 fprintf(stderr, "invalid timeout value\n");
 104                         dbg("timeout=%i\n", timeout);
 105                         break;
 106                 case 'h':
 107                         printf("Usage: udevadm settle [--help] [--timeout=<seconds>]\n\n");
 108                         goto exit;
 109                 }
 110         }
 111
 112         strlcpy(queuename, udev_root, sizeof(queuename));
 113         strlcat(queuename, "/.udev/queue", sizeof(queuename));
 114
 115         loop = timeout * LOOP_PER_SECOND;
 116         while (loop--) {
 117                 /* wait for events in queue to finish */
 118                 while (loop--) {
 119                         struct stat statbuf;
 120
 121                         if (stat(queuename, &statbuf) < 0) {
 122                                 info("queue is empty\n");
 123                                 break;
 124                         }
 125                         usleep(1000 * 1000 / LOOP_PER_SECOND);
 126                 }
 127                 if (loop <= 0) {
 128                         info("timeout waiting for queue\n");
 129                         print_queue(queuename);
 130                         goto exit;
 131                 }
 132
 133                 /* read current udev seqnum */
 134                 strlcpy(filename, udev_root, sizeof(filename));
 135                 strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 136                 fd = open(filename, O_RDONLY);
 137                 if (fd < 0)
 138                         goto exit;
 139                 len = read(fd, seqnum, sizeof(seqnum)-1);
 140                 close(fd);
 141                 if (len <= 0)
 142                         goto exit;
 143                 seqnum[len] = '\0';
 144                 seq_udev = strtoull(seqnum, NULL, 10);
 145                 info("udev seqnum = %llu\n", seq_udev);
 146
 147                 /* read current kernel seqnum */
 148                 strlcpy(filename, sysfs_path, sizeof(filename));
 149                 strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 150                 fd = open(filename, O_RDONLY);
 151                 if (fd < 0)
 152                         goto exit;
 153                 len = read(fd, seqnum, sizeof(seqnum)-1);
 154                 close(fd);
 155                 if (len <= 0)
 156                         goto exit;
 157                 seqnum[len] = '\0';
 158                 seq_kernel = strtoull(seqnum, NULL, 10);
 159                 info("kernel seqnum = %llu\n", seq_kernel);
 160
 161                 /* make sure all kernel events have arrived in the queue */
 162                 if (seq_udev >= seq_kernel) {
 163                         info("queue is empty and no pending events left\n");
 164                         rc = 0;
 165                         goto exit;
 166                 }
 167                 usleep(1000 * 1000 / LOOP_PER_SECOND);
 168                 info("queue is empty, but events still pending\n");
 169         }
 170
 171 exit:
 172         return rc;
 173 }