316 lines
6.4 KiB
C
316 lines
6.4 KiB
C
/*
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* udev.c
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*
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* Userspace devfs
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*
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* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
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*
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <errno.h>
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#include "udev.h"
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#include "udev_version.h"
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#include "namedev.h"
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#include "libsysfs/libsysfs.h"
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static char sysfs_path[SYSFS_PATH_MAX];
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static char *get_action(void)
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{
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char *action;
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action = getenv("ACTION");
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return action;
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}
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static char *get_device(void)
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{
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char *device;
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device = getenv("DEVPATH");
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return device;
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}
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/*
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* Right now the major/minor of a device is stored in a file called
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* "dev" in sysfs.
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* The number is stored as:
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* MMmm
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* MM is the major
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* mm is the minor
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* The value is in hex.
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* Yes, this will probably change when we go to a bigger major/minor
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* range, and will have to be changed at that time.
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*/
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static int get_major_minor(struct sysfs_class_device *class_dev, int *major, int *minor)
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{
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char temp[3];
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int retval = 0;
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char *dev;
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dev = sysfs_get_value_from_attributes(class_dev->directory->attributes, "dev");
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if (dev == NULL)
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return -ENODEV;
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dbg("dev = %s", dev);
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temp[0] = dev[0];
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temp[1] = dev[1];
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temp[2] = 0x00;
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*major = (int)strtol(&temp[0], NULL, 16);
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temp[0] = dev[2];
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temp[1] = dev[3];
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temp[2] = 0x00;
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*minor = (int)strtol(&temp[0], NULL, 16);
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dbg("found major = %d, minor = %d", *major, *minor);
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retval = 0;
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return retval;
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}
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/*
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* Here would go a call to the naming deamon, to get the name we want to have
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* for this device. But for now, let's just default to whatever the kernel is
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* calling the device as that will keep the "old-style" naming policy
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*/
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static char *get_name(char *dev, int major, int minor)
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{
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static char name[100];
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char *temp;
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temp = strrchr(dev, '/');
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if (temp == NULL)
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return NULL;
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strncpy(name, &temp[1], sizeof(name));
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dbg("name is %s", name);
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return &name[0];
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}
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/*
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* We also want to add some permissions here, and possibly some symlinks
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*/
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static int create_node(char *name, char type, int major, int minor, int mode)
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{
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char *argv[7];
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char mode_string[100];
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char type_string[3];
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char major_string[20];
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char minor_string[20];
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char filename[255];
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int retval = 0;
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strncpy(filename, UDEV_ROOT, sizeof(filename));
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strncat(filename, name, sizeof(filename));
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snprintf(mode_string, sizeof(mode_string), "--mode=%#o", mode);
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snprintf(type_string, sizeof(type_string), "%c", type);
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snprintf(major_string, sizeof(major_string), "%d", major);
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snprintf(minor_string, sizeof(minor_string), "%d", minor);
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argv[0] = MKNOD;
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argv[1] = mode_string;
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argv[2] = filename;
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argv[3] = type_string;
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argv[4] = major_string;
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argv[5] = minor_string;
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argv[6] = NULL;
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dbg ("executing %s %s %s %s %s %s",
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argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
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switch (fork()) {
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case 0:
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/* we are the child, so lets run the program */
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execv (MKNOD, argv);
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exit(0);
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break;
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case (-1):
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dbg ("fork failed.");
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retval = -EFAULT;
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break;
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default:
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break;
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}
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return retval;
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}
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/*
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* We also want to clean up any symlinks that were created in create_node()
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*/
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static int delete_node(char *name)
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{
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char filename[255];
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strncpy(filename, UDEV_ROOT, sizeof(filename));
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strncat(filename, name, sizeof(filename));
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dbg("unlinking %s", filename);
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return unlink(filename);
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}
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struct sysfs_class_device *get_class_dev(char *device_name)
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{
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char dev_path[SYSFS_PATH_MAX];
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struct sysfs_class_device *class_dev;
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strcpy(dev_path, sysfs_path);
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strcat(dev_path, device_name);
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dbg("looking at %s", dev_path);
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/* open up the sysfs class device for this thing... */
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class_dev = sysfs_open_class_device(dev_path);
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if (class_dev == NULL) {
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dbg ("sysfs_open_class_device failed");
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return NULL;
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}
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dbg("class_dev->name = %s", class_dev->name);
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return class_dev;
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}
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static int add_device(char *device, char *subsystem)
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{
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struct sysfs_class_device *class_dev;
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struct device_attr attr;
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//char *name;
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int major;
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int minor;
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char type;
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//int mode;
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int retval = -EINVAL;
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/* for now, the block layer is the only place where block devices are */
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if (strcmp(subsystem, "block") == 0)
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type = 'b';
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else
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type = 'c';
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class_dev = get_class_dev(device);
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if (class_dev == NULL)
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goto exit;
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retval = namedev_name_device(class_dev, &attr);
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if (retval)
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return retval;
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retval = get_major_minor(class_dev, &major, &minor);
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if (retval) {
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dbg ("get_major_minor failed");
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goto exit;
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}
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sysfs_close_class_device(class_dev);
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return create_node(attr.name, type, major, minor, attr.mode);
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exit:
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return retval;
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}
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static int remove_device(char *device)
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{
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char *name;
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int retval = 0;
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name = get_name(device, 0, 0);
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if (name == NULL) {
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dbg ("get_name failed");
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retval = -ENODEV;
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goto exit;
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}
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return delete_node(name);
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exit:
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return retval;
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}
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static int udev_init(void)
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{
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int retval;
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retval = sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX);
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dbg("sysfs_path = %s", sysfs_path);
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return retval;
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}
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int main(int argc, char *argv[])
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{
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char *action;
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char *device;
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int retval = -EINVAL;
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if (argc != 2) {
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dbg ("unknown number of arguments");
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goto exit;
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}
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device = get_device();
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if (!device) {
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dbg ("no device?");
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goto exit;
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}
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dbg("looking at %s", device);
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/* we only care about class devices and block stuff */
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if (!strstr(device, "class") &&
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!strstr(device, "block")) {
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dbg("not block or class");
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goto exit;
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}
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/* sleep for a second or two to give the kernel a chance to
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* create the dev file
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*/
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sleep(1);
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udev_init();
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namedev_init();
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action = get_action();
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if (!action) {
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dbg ("no action?");
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goto exit;
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}
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if (strcmp(action, "add") == 0)
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return add_device(device, argv[1]);
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if (strcmp(action, "remove") == 0)
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return remove_device(device);
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dbg("Unknown action: %s", action);
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return -EINVAL;
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retval = 0;
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exit:
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return retval;
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}
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