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/* vi: set sw=4 ts=4: */
/*
* finddev.c -- this routine attempts to find a particular device in
* /dev
*
* Copyright (C) 2000 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#include <dirent.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_MKDEV_H
#include <sys/mkdev.h>
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
struct dir_list {
char *name;
struct dir_list *next;
};
/*
* This function adds an entry to the directory list
*/
static void add_to_dirlist(const char *name, struct dir_list **list)
{
struct dir_list *dp;
dp = xmalloc(sizeof(struct dir_list));
dp->name = xmalloc(strlen(name)+1);
strcpy(dp->name, name);
dp->next = *list;
*list = dp;
}
/*
* This function frees a directory list
*/
static void free_dirlist(struct dir_list **list)
{
struct dir_list *dp, *next;
for (dp = *list; dp; dp = next) {
next = dp->next;
free(dp->name);
free(dp);
}
*list = 0;
}
static int scan_dir(char *dir_name, dev_t device, struct dir_list **list,
char **ret_path)
{
DIR *dir;
struct dirent *dp;
char path[1024], *cp;
int dirlen;
struct stat st;
dirlen = strlen(dir_name);
if ((dir = opendir(dir_name)) == NULL)
return errno;
dp = readdir(dir);
while (dp) {
if (dirlen + strlen(dp->d_name) + 2 >= sizeof(path))
goto skip_to_next;
if (dp->d_name[0] == '.' &&
((dp->d_name[1] == 0) ||
((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
goto skip_to_next;
sprintf(path, "%s/%s", dir_name, dp->d_name);
if (stat(path, &st) < 0)
goto skip_to_next;
if (S_ISDIR(st.st_mode))
add_to_dirlist(path, list);
if (S_ISBLK(st.st_mode) && st.st_rdev == device) {
cp = xmalloc(strlen(path)+1);
strcpy(cp, path);
*ret_path = cp;
goto success;
}
skip_to_next:
dp = readdir(dir);
}
success:
closedir(dir);
return 0;
}
/*
* This function finds the pathname to a block device with a given
* device number. It returns a pointer to allocated memory to the
* pathname on success, and NULL on failure.
*/
char *ext2fs_find_block_device(dev_t device)
{
struct dir_list *list = 0, *new_list = 0;
struct dir_list *current;
char *ret_path = 0;
/*
* Add the starting directories to search...
*/
add_to_dirlist("/devices", &list);
add_to_dirlist("/devfs", &list);
add_to_dirlist("/dev", &list);
while (list) {
current = list;
list = list->next;
#ifdef DEBUG
printf("Scanning directory %s\n", current->name);
#endif
scan_dir(current->name, device, &new_list, &ret_path);
free(current->name);
free(current);
if (ret_path)
break;
/*
* If we're done checking at this level, descend to
* the next level of subdirectories. (breadth-first)
*/
if (list == 0) {
list = new_list;
new_list = 0;
}
}
free_dirlist(&list);
free_dirlist(&new_list);
return ret_path;
}
#ifdef DEBUG
int main(int argc, char** argv)
{
char *devname, *tmp;
int major, minor;
dev_t device;
const char *errmsg = "Cannot parse %s: %s\n";
if ((argc != 2) && (argc != 3)) {
fprintf(stderr, "Usage: %s device_number\n", argv[0]);
fprintf(stderr, "\t: %s major minor\n", argv[0]);
exit(1);
}
if (argc == 2) {
device = strtoul(argv[1], &tmp, 0);
if (*tmp) {
fprintf(stderr, errmsg, "device number", argv[1]);
exit(1);
}
} else {
major = strtoul(argv[1], &tmp, 0);
if (*tmp) {
fprintf(stderr, errmsg, "major number", argv[1]);
exit(1);
}
minor = strtoul(argv[2], &tmp, 0);
if (*tmp) {
fprintf(stderr, errmsg, "minor number", argv[2]);
exit(1);
}
device = makedev(major, minor);
printf("Looking for device 0x%04x (%d:%d)\n", device,
major, minor);
}
devname = ext2fs_find_block_device(device);
if (devname) {
printf("Found device! %s\n", devname);
free(devname);
} else {
printf("Cannot find device.\n");
}
return 0;
}
#endif
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