[821] | 1 | /*
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| 2 | * finddev.c -- this routine attempts to find a particular device in
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| 3 | * /dev
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| 4 | *
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| 5 | * Copyright (C) 2000 Theodore Ts'o.
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| 6 | *
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| 7 | * %Begin-Header%
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| 8 | * This file may be redistributed under the terms of the GNU Public
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| 9 | * License.
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| 10 | * %End-Header%
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| 11 | */
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| 12 |
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| 13 | #include <stdio.h>
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| 14 | #include <string.h>
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| 15 | #if HAVE_UNISTD_H
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| 16 | #include <unistd.h>
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| 17 | #endif
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| 18 | #include <stdlib.h>
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| 19 | #include <string.h>
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| 20 | #if HAVE_SYS_TYPES_H
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| 21 | #include <sys/types.h>
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| 22 | #endif
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| 23 | #if HAVE_SYS_STAT_H
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| 24 | #include <sys/stat.h>
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| 25 | #endif
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| 26 | #include <dirent.h>
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| 27 | #if HAVE_ERRNO_H
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| 28 | #include <errno.h>
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| 29 | #endif
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| 30 | #if HAVE_SYS_MKDEV_H
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| 31 | #include <sys/mkdev.h>
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| 32 | #endif
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| 33 |
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| 34 | #include "ext2_fs.h"
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| 35 | #include "ext2fs.h"
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| 36 |
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| 37 | struct dir_list {
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| 38 | char *name;
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| 39 | struct dir_list *next;
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| 40 | };
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| 41 |
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| 42 | /*
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| 43 | * This function adds an entry to the directory list
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| 44 | */
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| 45 | static void add_to_dirlist(const char *name, struct dir_list **list)
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| 46 | {
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| 47 | struct dir_list *dp;
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| 48 |
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| 49 | dp = xmalloc(sizeof(struct dir_list));
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| 50 | dp->name = xmalloc(strlen(name)+1);
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| 51 | strcpy(dp->name, name);
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| 52 | dp->next = *list;
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| 53 | *list = dp;
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| 54 | }
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| 55 |
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| 56 | /*
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| 57 | * This function frees a directory list
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| 58 | */
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| 59 | static void free_dirlist(struct dir_list **list)
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| 60 | {
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| 61 | struct dir_list *dp, *next;
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| 62 |
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| 63 | for (dp = *list; dp; dp = next) {
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| 64 | next = dp->next;
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| 65 | free(dp->name);
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| 66 | free(dp);
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| 67 | }
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| 68 | *list = 0;
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| 69 | }
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| 70 |
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| 71 | static int scan_dir(char *dir_name, dev_t device, struct dir_list **list,
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| 72 | char **ret_path)
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| 73 | {
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| 74 | DIR *dir;
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| 75 | struct dirent *dp;
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| 76 | char path[1024], *cp;
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| 77 | int dirlen;
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| 78 | struct stat st;
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| 79 |
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| 80 | dirlen = strlen(dir_name);
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| 81 | if ((dir = opendir(dir_name)) == NULL)
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| 82 | return errno;
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| 83 | dp = readdir(dir);
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| 84 | while (dp) {
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| 85 | if (dirlen + strlen(dp->d_name) + 2 >= sizeof(path))
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| 86 | goto skip_to_next;
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| 87 | if (dp->d_name[0] == '.' &&
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| 88 | ((dp->d_name[1] == 0) ||
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| 89 | ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
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| 90 | goto skip_to_next;
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| 91 | sprintf(path, "%s/%s", dir_name, dp->d_name);
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| 92 | if (stat(path, &st) < 0)
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| 93 | goto skip_to_next;
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| 94 | if (S_ISDIR(st.st_mode))
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| 95 | add_to_dirlist(path, list);
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| 96 | if (S_ISBLK(st.st_mode) && st.st_rdev == device) {
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| 97 | cp = xmalloc(strlen(path)+1);
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| 98 | strcpy(cp, path);
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| 99 | *ret_path = cp;
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| 100 | goto success;
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| 101 | }
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| 102 | skip_to_next:
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| 103 | dp = readdir(dir);
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| 104 | }
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| 105 | success:
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| 106 | closedir(dir);
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| 107 | return 0;
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| 108 | }
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| 109 |
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| 110 | /*
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| 111 | * This function finds the pathname to a block device with a given
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| 112 | * device number. It returns a pointer to allocated memory to the
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| 113 | * pathname on success, and NULL on failure.
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| 114 | */
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| 115 | char *ext2fs_find_block_device(dev_t device)
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| 116 | {
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| 117 | struct dir_list *list = 0, *new_list = 0;
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| 118 | struct dir_list *current;
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| 119 | char *ret_path = 0;
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| 120 |
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| 121 | /*
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| 122 | * Add the starting directories to search...
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| 123 | */
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| 124 | add_to_dirlist("/devices", &list);
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| 125 | add_to_dirlist("/devfs", &list);
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| 126 | add_to_dirlist("/dev", &list);
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| 127 |
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| 128 | while (list) {
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| 129 | current = list;
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| 130 | list = list->next;
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| 131 | #ifdef DEBUG
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| 132 | printf("Scanning directory %s\n", current->name);
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| 133 | #endif
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| 134 | scan_dir(current->name, device, &new_list, &ret_path);
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| 135 | free(current->name);
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| 136 | free(current);
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| 137 | if (ret_path)
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| 138 | break;
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| 139 | /*
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| 140 | * If we're done checking at this level, descend to
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| 141 | * the next level of subdirectories. (breadth-first)
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| 142 | */
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| 143 | if (list == 0) {
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| 144 | list = new_list;
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| 145 | new_list = 0;
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| 146 | }
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| 147 | }
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| 148 | free_dirlist(&list);
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| 149 | free_dirlist(&new_list);
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| 150 | return ret_path;
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| 151 | }
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| 152 |
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| 153 |
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| 154 | #ifdef DEBUG
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| 155 | int main(int argc, char** argv)
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| 156 | {
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| 157 | char *devname, *tmp;
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| 158 | int major, minor;
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| 159 | dev_t device;
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| 160 | const char *errmsg = "Couldn't parse %s: %s\n";
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| 161 |
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| 162 | if ((argc != 2) && (argc != 3)) {
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| 163 | fprintf(stderr, "Usage: %s device_number\n", argv[0]);
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| 164 | fprintf(stderr, "\t: %s major minor\n", argv[0]);
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| 165 | exit(1);
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| 166 | }
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| 167 | if (argc == 2) {
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| 168 | device = strtoul(argv[1], &tmp, 0);
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| 169 | if (*tmp) {
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| 170 | fprintf(stderr, errmsg, "device number", argv[1]);
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| 171 | exit(1);
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| 172 | }
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| 173 | } else {
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| 174 | major = strtoul(argv[1], &tmp, 0);
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| 175 | if (*tmp) {
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| 176 | fprintf(stderr, errmsg, "major number", argv[1]);
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| 177 | exit(1);
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| 178 | }
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| 179 | minor = strtoul(argv[2], &tmp, 0);
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| 180 | if (*tmp) {
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| 181 | fprintf(stderr, errmsg, "minor number", argv[2]);
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| 182 | exit(1);
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| 183 | }
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| 184 | device = makedev(major, minor);
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| 185 | printf("Looking for device 0x%04x (%d:%d)\n", device,
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| 186 | major, minor);
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| 187 | }
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| 188 | devname = ext2fs_find_block_device(device);
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| 189 | if (devname) {
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| 190 | printf("Found device! %s\n", devname);
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| 191 | free(devname);
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| 192 | } else {
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| 193 | printf("Couldn't find device.\n");
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| 194 | }
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| 195 | return 0;
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| 196 | }
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| 197 |
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| 198 | #endif
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