udev_multiplex.c

   1 /*
   2  * udev_multiplex.c directory multiplexer
   3  *
   4  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  */
  10
  11 /*
  12  * This essentially emulates the following shell script logic in C:
  13  *      DIR="/etc/dev.d"
  14  *      export DEVNAME="whatever_dev_name_udev_just_gave"
  15  *      for I in "${DIR}/$DEVNAME/"*.dev "${DIR}/$1/"*.dev "${DIR}/default/"*.dev ; do
  16  *              if [ -f $I ]; then $I $1 ; fi
  17  *      done
  18  *      exit 1;
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29
  30 #include "udev.h"
  31 #include "udev_libc_wrapper.h"
  32 #include "udev_utils.h"
  33 #include "logging.h"
  34
  35 static int run_program(struct udevice *udev, const char *filename)
  36 {
  37         pid_t pid;
  38         int fd;
  39
  40         dbg("running %s", filename);
  41
  42         pid = fork();
  43         switch (pid) {
  44         case 0:
  45                 /* child */
  46                 fd = open("/dev/null", O_RDWR);
  47                 if ( fd >= 0) {
  48                         dup2(fd, STDOUT_FILENO);
  49                         dup2(fd, STDIN_FILENO);
  50                         dup2(fd, STDERR_FILENO);
  51                 }
  52                 close(fd);
  53
  54                 execl(filename, filename, udev->subsystem, NULL);
  55                 dbg("exec of child failed");
  56                 _exit(1);
  57         case -1:
  58                 dbg("fork of child failed");
  59                 break;
  60                 return -1;
  61         default:
  62                 waitpid(pid, NULL, 0);
  63         }
  64
  65         return 0;
  66 }
  67
  68 /*
  69  * runs files in these directories in order:
  70  *      <node name given by udev>/
  71  *      subsystem/
  72  *      default/
  73  */
  74 void udev_multiplex_directory(struct udevice *udev, const char *basedir, const char *suffix)
  75 {
  76         char dirname[PATH_SIZE];
  77         struct name_entry *name_loop, *name_tmp;
  78         LIST_HEAD(name_list);
  79
  80         /* chop the device name up into pieces based on '/' */
  81         if (udev->name[0] != '\0') {
  82                 char devname[PATH_SIZE];
  83                 char *temp;
  84
  85                 strlcpy(devname, udev->name, sizeof(devname));
  86                 temp = strchr(devname, '/');
  87                 while (temp != NULL) {
  88                         temp[0] = '\0';
  89
  90                         /* don't call the subsystem directory here */
  91                         if (strcmp(devname, udev->subsystem) != 0) {
  92                                 snprintf(dirname, sizeof(dirname), "%s/%s", basedir, devname);
  93                                 dirname[sizeof(dirname)-1] = '\0';
  94                                 add_matching_files(&name_list, dirname, suffix);
  95                         }
  96
  97                         temp[0] = '/';
  98                         ++temp;
  99                         temp = strchr(temp, '/');
 100                 }
 101         }
 102
 103         if (udev->name[0] != '\0') {
 104                 snprintf(dirname, sizeof(dirname), "%s/%s", basedir, udev->name);
 105                 dirname[sizeof(dirname)-1] = '\0';
 106                 add_matching_files(&name_list, dirname, suffix);
 107         }
 108
 109         if (udev->subsystem[0] != '\0') {
 110                 snprintf(dirname, sizeof(dirname), "%s/%s", basedir, udev->subsystem);
 111                 dirname[sizeof(dirname)-1] = '\0';
 112                 add_matching_files(&name_list, dirname, suffix);
 113         }
 114
 115         snprintf(dirname, sizeof(dirname), "%s/default", basedir);
 116         dirname[sizeof(dirname)-1] = '\0';
 117         add_matching_files(&name_list, dirname, suffix);
 118
 119         list_for_each_entry_safe(name_loop, name_tmp, &name_list, node) {
 120                 run_program(udev, name_loop->name);
 121                 list_del(&name_loop->node);
 122         }
 123
 124 }