udev-add.c

   1 /*
   2  * udev-add.c
   3  *
   4  * Userspace devfs
   5  *
   6  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
   7  *
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License as published by the
  11  *      Free Software Foundation version 2 of the License.
  12  *
  13  *      This program is distributed in the hope that it will be useful, but
  14  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *      General Public License for more details.
  17  *
  18  *      You should have received a copy of the GNU General Public License along
  19  *      with this program; if not, write to the Free Software Foundation, Inc.,
  20  *      675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  */
  23
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include <fcntl.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30
  31 #include "udev.h"
  32 #include "udev_version.h"
  33 #include "namedev.h"
  34 #include "udevdb.h"
  35 #include "libsysfs/libsysfs.h"
  36
  37
  38 /*
  39  * Right now the major/minor of a device is stored in a file called
  40  * "dev" in sysfs.
  41  * The number is stored as:
  42  *      MMmm
  43  *              MM is the major
  44  *              mm is the minor
  45  *              The value is in hex.
  46  * Yes, this will probably change when we go to a bigger major/minor
  47  * range, and will have to be changed at that time.
  48  */
  49 static int get_major_minor(struct sysfs_class_device *class_dev, int *major, int *minor)
  50 {
  51         int retval = -ENODEV;
  52
  53         char *dev;
  54
  55         dev = sysfs_get_value_from_attributes(class_dev->directory->attributes, "dev");
  56         if (dev == NULL)
  57                 goto exit;
  58
  59         dbg("dev = %s", dev);
  60
  61         if (sscanf(dev, "%u:%u", major, minor) != 2)
  62                 goto exit;
  63
  64         dbg("found major = %d, minor = %d", *major, *minor);
  65
  66         retval = 0;
  67 exit:
  68         return retval;
  69 }
  70
  71 /*
  72  * We also want to add some permissions here, and possibly some symlinks
  73  */
  74 static int create_node(char *name, char type, int major, int minor, int mode)
  75 {
  76         char filename[255];
  77         int retval = 0;
  78         strncpy(filename, UDEV_ROOT, sizeof(filename));
  79         strncat(filename, name, sizeof(filename));
  80         switch (type) {
  81         case 'b':
  82                 mode |= S_IFBLK;
  83                 break;
  84         case 'c':
  85         case 'u':
  86                 mode |= S_IFCHR;
  87                 break;
  88         case 'p':
  89                 mode |= S_IFIFO;
  90                 break;
  91         default:
  92                 dbg("unknown node type %c\n", type);
  93                 return -EINVAL;
  94         }
  95
  96         retval = mknod(filename,mode,makedev(major,minor));
  97         if (retval)
  98                 dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
  99                     filename, mode, major, minor, strerror(errno));
 100         return retval;
 101 }
 102
 103 struct sysfs_class_device *get_class_dev(char *device_name)
 104 {
 105         char sysfs_path[SYSFS_PATH_MAX];
 106         char dev_path[SYSFS_PATH_MAX];
 107         int retval;
 108         struct sysfs_class_device *class_dev = NULL;
 109
 110
 111         retval = sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX);
 112         dbg("sysfs_path = %s", sysfs_path);
 113         if (retval) {
 114                 dbg("sysfs_get_mnt_path failed");
 115                 goto exit;
 116         }
 117
 118         strcpy(dev_path, sysfs_path);
 119         strcat(dev_path, device_name);
 120
 121         dbg("looking at %s", dev_path);
 122
 123         /* open up the sysfs class device for this thing... */
 124         class_dev = sysfs_open_class_device(dev_path);
 125         if (class_dev == NULL) {
 126                 dbg ("sysfs_open_class_device failed");
 127                 goto exit;
 128         }
 129         dbg("class_dev->name = %s", class_dev->name);
 130
 131 exit:
 132         return class_dev;
 133 }
 134
 135 int udev_add_device(char *device, char *subsystem)
 136 {
 137         struct sysfs_class_device *class_dev;
 138         struct device_attr attr;
 139         int major;
 140         int minor;
 141         char type;
 142         int retval = -EINVAL;
 143
 144         /* for now, the block layer is the only place where block devices are */
 145         if (strcmp(subsystem, "block") == 0)
 146                 type = 'b';
 147         else
 148                 type = 'c';
 149
 150         /* sleep for a second or two to give the kernel a chance to
 151          * create the dev file
 152          */
 153         sleep(1);
 154
 155         class_dev = get_class_dev(device);
 156         if (class_dev == NULL)
 157                 goto exit;
 158
 159         retval = namedev_name_device(class_dev, &attr);
 160         if (retval)
 161                 return retval;
 162
 163         retval = get_major_minor(class_dev, &major, &minor);
 164         if (retval) {
 165                 dbg ("get_major_minor failed");
 166                 goto exit;
 167         }
 168         memset(&dbdev, 0, sizeof(dbdev));
 169         strncpy(dbdev.name, attr.name, NAME_SIZE);
 170         strncpy(dbdev.sysfs_path, class_dev->sysdevice->directory->path,
 171                 PATH_SIZE);
 172         strncpy(dbdev.class_dev_name, class_dev->name, NAME_SIZE);
 173         if ((sysfs_get_name_from_path(subsystem, dbdev.class_name, NAME_SIZE))
 174             != 0)
 175                 strcpy(dbdev.class_name, "unkown");
 176         strncpy(dbdev.bus_id, class_dev->sysdevice->bus_id, ID_SIZE);
 177         strcpy(dbdev.bus_name, "unknown");
 178         if (class_dev->driver != NULL)
 179                 strncpy(dbdev.driver, class_dev->driver->name, NAME_SIZE);
 180         else
 181                 strcpy(dbdev.driver, "unkown");
 182         dbdev.type = type;
 183         dbdev.major = major;
 184         dbdev.minor = minor;
 185         dbdev.mode = attr.mode;
 186
 187         sysfs_close_class_device(class_dev);
 188
 189         retval = udevdb_add_udevice(&dbdev);
 190         if (retval != 0)
 191                 goto exit;
 192
 193         return create_node(attr.name, type, major, minor, attr.mode);
 194
 195 exit:
 196         return retval;
 197 }
 198