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https://github.com/systemd/systemd
synced 2024-10-04 15:21:01 +00:00
[PATCH] Creating nodes actually works.
This commit is contained in:
parent
a2fd2ff38a
commit
85511f0246
207
udev.c
207
udev.c
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@ -23,6 +23,11 @@
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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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@ -36,11 +41,9 @@ static char *get_action(void)
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}
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/* yeah this should be dynamically allocated... */
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static char device[255];
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static char *get_device(void)
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{
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static char device[255];
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char *temp;
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temp = getenv("DEVPATH");
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@ -52,32 +55,216 @@ static char *get_device(void)
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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 (char *dev, int *major, int *minor)
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{
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char filename[255];
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char line[20];
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char temp[3];
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int fd;
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int retval = 0;
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/* add the dev file to the directory and see if it's present */
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strncpy(filename, dev, sizeof(filename));
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strncat(filename, DEV_FILE, sizeof(filename));
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fd = open(filename, O_RDONLY);
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if (fd < 0) {
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dbg("Can't open %s", filename);
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return -ENODEV;
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}
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/* get the major/minor */
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retval = read(fd, line, sizeof(line));
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if (retval < 0) {
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dbg("read error on %s", dev);
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goto exit;
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}
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temp[0] = line[0];
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temp[1] = line[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] = line[2];
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temp[1] = line[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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exit:
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close(fd);
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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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* Again, this will live in the naming deamon
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*/
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static int get_mode(char *name, char *dev, int major, int minor)
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{
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/* just default everyone to rw for the world! */
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return 0666;
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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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static int remove_node(char *name)
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{
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return 0;
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}
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static int do_it(char *action, char *name, char type, int major, int minor, int mode)
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{
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if (strcmp(action, "add") == 0)
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return create_node(name, type, major, minor, mode);
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if (strcmp(action, "remove") == 0)
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return remove_node(name);
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dbg("Unknown action: %s", action);
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return -EINVAL;
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}
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int main(int argc, char *argv[])
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{
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char *subsystem;
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char *action;
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char *dev;
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char *device;
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char *name;
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char type;
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int major;
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int minor;
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int mode;
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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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return 1;
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goto exit;
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}
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/* for now, the block layer is the only place where block devices are */
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subsystem = argv[1];
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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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action = get_action();
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if (!action) {
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dbg ("no action?");
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return 1;
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goto exit;
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}
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dev = get_device();
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if (!dev) {
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device = get_device();
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if (!device) {
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dbg ("no device?");
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return 1;
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goto exit;
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}
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dbg("looking at %s", device);
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retval = get_major_minor(device, &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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return 0;
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name = get_name(device, major, minor);
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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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mode = get_mode(name, device, major, minor);
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if (mode < 0) {
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dbg ("get_mode failed");
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retval = -EINVAL;
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goto exit;
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}
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retval = do_it(action, name, type, major, minor, mode);
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if (retval) {
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dbg ("do_it failed");
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goto exit;
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}
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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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11
udev.h
11
udev.h
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@ -36,10 +36,21 @@
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/* Lots of constants that should be in a config file sometime */
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/* Location of sysfs mount */
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#define SYSFS_ROOT "/sys"
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/* Where udev should create its device nodes, trailing / needed */
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#define UDEV_ROOT "/home/greg/linux/udev/"
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/* device file in sysfs that contains major/minor number, leading / needed */
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#define DEV_FILE "/dev"
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/* Binaries that udev calls to do stuff */
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#define MKNOD "/bin/mknod"
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extern int log_message (int level, const char *format, ...);
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