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[PATCH] Creating nodes actually works.

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gregkh committed Apr 10, 2003
1 parent a2fd2ff commit 85511f02466297b7dca07c3fe5491230f3f06d14
Showing with 208 additions and 10 deletions.
  1. +197 −10 udev.c
  2. +11 −0 udev.h
207 udev.c
@@ -23,6 +23,11 @@

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

#include "udev.h"
#include "udev_version.h"

@@ -36,11 +41,9 @@ static char *get_action(void)
}


/* yeah this should be dynamically allocated... */
static char device[255];

static char *get_device(void)
{
static char device[255];
char *temp;

temp = getenv("DEVPATH");
@@ -52,32 +55,216 @@ static char *get_device(void)
return device;
}

/*
* Right now the major/minor of a device is stored in a file called
* "dev" in sysfs.
* The number is stored as:
* MMmm
* MM is the major
* mm is the minor
* The value is in hex.
* Yes, this will probably change when we go to a bigger major/minor
* range, and will have to be changed at that time.
*/
static int get_major_minor (char *dev, int *major, int *minor)
{
char filename[255];
char line[20];
char temp[3];
int fd;
int retval = 0;

/* add the dev file to the directory and see if it's present */
strncpy(filename, dev, sizeof(filename));
strncat(filename, DEV_FILE, sizeof(filename));
fd = open(filename, O_RDONLY);
if (fd < 0) {
dbg("Can't open %s", filename);
return -ENODEV;
}

/* get the major/minor */
retval = read(fd, line, sizeof(line));
if (retval < 0) {
dbg("read error on %s", dev);
goto exit;
}

temp[0] = line[0];
temp[1] = line[1];
temp[2] = 0x00;
*major = (int)strtol(&temp[0], NULL, 16);

temp[0] = line[2];
temp[1] = line[3];
temp[2] = 0x00;
*minor = (int)strtol(&temp[0], NULL, 16);

dbg("found major = %d, minor = %d", *major, *minor);

retval = 0;
exit:
close(fd);
return retval;
}

/*
* Here would go a call to the naming deamon, to get the name we want to have
* for this device. But for now, let's just default to whatever the kernel is
* calling the device as that will keep the "old-style" naming policy
*/
static char *get_name(char *dev, int major, int minor)
{
static char name[100];
char *temp;

temp = strrchr(dev, '/');
if (temp == NULL)
return NULL;
strncpy(name, &temp[1], sizeof(name));

dbg("name is %s", name);

return &name[0];
}

/*
* Again, this will live in the naming deamon
*/
static int get_mode(char *name, char *dev, int major, int minor)
{
/* just default everyone to rw for the world! */
return 0666;
}

/*
* We also want to add some permissions here, and possibly some symlinks
*/
static int create_node(char *name, char type, int major, int minor, int mode)
{
char *argv[7];
char mode_string[100];
char type_string[3];
char major_string[20];
char minor_string[20];
char filename[255];
int retval = 0;

strncpy(filename, UDEV_ROOT, sizeof(filename));
strncat(filename, name, sizeof(filename));

snprintf(mode_string, sizeof(mode_string), "--mode=%#o", mode);
snprintf(type_string, sizeof(type_string), "%c", type);
snprintf(major_string, sizeof(major_string), "%d", major);
snprintf(minor_string, sizeof(minor_string), "%d", minor);

argv[0] = MKNOD;
argv[1] = mode_string;
argv[2] = filename;
argv[3] = type_string;
argv[4] = major_string;
argv[5] = minor_string;
argv[6] = NULL;
dbg ("executing %s %s %s %s %s %s",
argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
switch (fork()) {
case 0:
/* we are the child, so lets run the program */
execv (MKNOD, argv);
exit(0);
break;
case (-1):
dbg ("fork failed.");
retval = -EFAULT;
break;
default:
break;
}
return retval;
}

static int remove_node(char *name)
{
return 0;
}

static int do_it(char *action, char *name, char type, int major, int minor, int mode)
{
if (strcmp(action, "add") == 0)
return create_node(name, type, major, minor, mode);

if (strcmp(action, "remove") == 0)
return remove_node(name);

dbg("Unknown action: %s", action);
return -EINVAL;
}

int main(int argc, char *argv[])
{
char *subsystem;
char *action;
char *dev;
char *device;
char *name;
char type;
int major;
int minor;
int mode;
int retval = -EINVAL;

if (argc != 2) {
dbg ("unknown number of arguments");
return 1;
goto exit;
}

/* for now, the block layer is the only place where block devices are */
subsystem = argv[1];
if (strcmp(subsystem, "block") == 0)
type = 'b';
else
type = 'c';

action = get_action();
if (!action) {
dbg ("no action?");
return 1;
goto exit;
}

dev = get_device();
if (!dev) {
device = get_device();
if (!device) {
dbg ("no device?");
return 1;
goto exit;
}
dbg("looking at %s", device);

return 0;
retval = get_major_minor(device, &major, &minor);
if (retval) {
dbg ("get_major_minor failed");
goto exit;
}

name = get_name(device, major, minor);
if (name == NULL) {
dbg ("get_name failed");
retval = -ENODEV;
goto exit;
}

mode = get_mode(name, device, major, minor);
if (mode < 0) {
dbg ("get_mode failed");
retval = -EINVAL;
goto exit;
}

retval = do_it(action, name, type, major, minor, mode);
if (retval) {
dbg ("do_it failed");
goto exit;
}

retval = 0;
exit:
return retval;
}

11 udev.h
@@ -36,10 +36,21 @@


/* Lots of constants that should be in a config file sometime */

/* Location of sysfs mount */
#define SYSFS_ROOT "/sys"

/* Where udev should create its device nodes, trailing / needed */
#define UDEV_ROOT "/home/greg/linux/udev/"

/* device file in sysfs that contains major/minor number, leading / needed */
#define DEV_FILE "/dev"

/* Binaries that udev calls to do stuff */
#define MKNOD "/bin/mknod"



extern int log_message (int level, const char *format, ...);


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