wait_for_sysfs.c

   1 /*
   2  * wait_for_sysfs.c  - small program to delay the execution
   3  *                     of /etc/hotplug.d/ programs, until sysfs
   4  *                     is fully populated by the kernel. Depending on
   5  *                     the type of device, we wait for all expected
   6  *                     directories and then just exit.
   7  *
   8  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   9  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
  10  *
  11  *      This program is free software; you can redistribute it and/or modify it
  12  *      under the terms of the GNU General Public License as published by the
  13  *      Free Software Foundation version 2 of the License.
  14  *
  15  *      This program is distributed in the hope that it will be useful, but
  16  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *      General Public License for more details.
  19  *
  20  *      You should have received a copy of the GNU General Public License along
  21  *      with this program; if not, write to the Free Software Foundation, Inc.,
  22  *      675 Mass Ave, Cambridge, MA 02139, USA.
  23  *
  24  */
  25
  26 #include <stdio.h>
  27 #include <stddef.h>
  28 #include <stdlib.h>
  29 #include <unistd.h>
  30 #include <string.h>
  31 #include <ctype.h>
  32 #include <errno.h>
  33 #include <sys/stat.h>
  34
  35 #include "logging.h"
  36 #include "udev_version.h"
  37 #include "udev_sysfs.h"
  38 #include "libsysfs/sysfs/libsysfs.h"
  39
  40 #ifdef LOG
  41 unsigned char logname[LOGNAME_SIZE];
  42 void log_message(int level, const char *format, ...)
  43 {
  44         va_list args;
  45
  46         va_start(args, format);
  47         vsyslog(level, format, args);
  48         va_end(args);
  49 }
  50 #endif
  51
  52 int main(int argc, char *argv[], char *envp[])
  53 {
  54         const char *devpath = "";
  55         const char *action;
  56         const char *subsystem;
  57         char sysfs_mnt_path[SYSFS_PATH_MAX];
  58         char filename[SYSFS_PATH_MAX];
  59         struct sysfs_class_device *class_dev;
  60         struct sysfs_device *devices_dev;
  61         int rc = 0;
  62         const char *error = NULL;
  63
  64         logging_init("wait_for_sysfs");
  65
  66         if (argc != 2) {
  67                 dbg("error: subsystem");
  68                 return 1;
  69         }
  70         subsystem = argv[1];
  71
  72         devpath = getenv ("DEVPATH");
  73         if (!devpath) {
  74                 dbg("error: no DEVPATH");
  75                 rc = 1;
  76                 goto exit;
  77         }
  78
  79         action = getenv ("ACTION");
  80         if (!action) {
  81                 dbg("error: no ACTION");
  82                 rc = 1;
  83                 goto exit;
  84         }
  85
  86         /* we only wait on an add event */
  87         if (strcmp(action, "add") != 0) {
  88                 dbg("no add ACTION");
  89                 goto exit;
  90         }
  91
  92         if (sysfs_get_mnt_path(sysfs_mnt_path, SYSFS_PATH_MAX) != 0) {
  93                 dbg("error: no sysfs path");
  94                 rc = 2;
  95                 goto exit;
  96         }
  97
  98         if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
  99                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_mnt_path, devpath);
 100                 filename[SYSFS_PATH_MAX-1] = '\0';
 101
 102                 /* skip bad events where we get no device for the class */
 103                 if (strncmp(devpath, "/class/", 7) == 0 && strchr(&devpath[7], '/') == NULL) {
 104                         dbg("no device name for '%s', bad event", devpath);
 105                         goto exit;
 106                 }
 107
 108                 /* open the class device we are called for */
 109                 class_dev = open_class_device_wait(filename);
 110                 if (!class_dev) {
 111                         dbg("error: class device unavailable (probably remove has beaten us)");
 112                         goto exit;
 113                 }
 114                 dbg("class device opened '%s'", filename);
 115
 116                 /* wait for the class device with possible physical device and bus */
 117                 wait_for_class_device(class_dev, &error);
 118
 119                 sysfs_close_class_device(class_dev);
 120
 121         } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
 122                 snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_mnt_path, devpath);
 123                 filename[SYSFS_PATH_MAX-1] = '\0';
 124
 125                 /* open the path we are called for */
 126                 devices_dev = open_devices_device_wait(filename);
 127                 if (!devices_dev) {
 128                         dbg("error: devices device unavailable (probably remove has beaten us)");
 129                         goto exit;
 130                 }
 131                 dbg("devices device opened '%s'", filename);
 132
 133                 /* wait for the bus value */
 134                 wait_for_bus_device(devices_dev, &error);
 135
 136                 sysfs_close_device(devices_dev);
 137
 138         } else {
 139                 dbg("unhandled sysfs path, no need to wait");
 140         }
 141
 142 exit:
 143         if (error) {
 144                 info("either wait_for_sysfs (udev %s) needs an update to handle the device '%s' "
 145                      "properly (%s) or the sysfs-support of your device's driver needs to be fixed, "
 146                      "please report to <linux-hotplug-devel@lists.sourceforge.net>",
 147                      UDEV_VERSION, devpath, error);
 148                 rc =3;
 149         } else {
 150                 dbg("result: waiting for sysfs successful '%s'", devpath);
 151         }
 152
 153         logging_close();
 154         exit(rc);
 155 }