1 /* 2 * finddev.c -- this routine attempts to find a particular device in 3 * /dev 4 * 5 * Copyright (C) 2000 Theodore Ts'o. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Library 9 * General Public License, version 2. 10 * %End-Header% 11 */ 12 13 #include "config.h" 14 #include <stdio.h> 15 #include <string.h> 16 #if HAVE_UNISTD_H 17 #include <unistd.h> 18 #endif 19 #include <stdlib.h> 20 #include <string.h> 21 #if HAVE_SYS_TYPES_H 22 #include <sys/types.h> 23 #endif 24 #if HAVE_SYS_STAT_H 25 #include <sys/stat.h> 26 #endif 27 #include <dirent.h> 28 #if HAVE_ERRNO_H 29 #include <errno.h> 30 #endif 31 #if HAVE_SYS_MKDEV_H 32 #include <sys/mkdev.h> 33 #endif 34 #ifdef HAVE_SYS_SYSMACROS_H 35 #include <sys/sysmacros.h> 36 #endif 37 38 #include "ext2_fs.h" 39 #include "ext2fs.h" 40 #include "ext2fsP.h" 41 42 struct dir_list { 43 char *name; 44 struct dir_list *next; 45 }; 46 47 /* 48 * This function adds an entry to the directory list 49 */ 50 static void add_to_dirlist(const char *name, struct dir_list **list) 51 { 52 struct dir_list *dp; 53 54 dp = malloc(sizeof(struct dir_list)); 55 if (!dp) 56 return; 57 dp->name = malloc(strlen(name)+1); 58 if (!dp->name) { 59 free(dp); 60 return; 61 } 62 strcpy(dp->name, name); 63 dp->next = *list; 64 *list = dp; 65 } 66 67 /* 68 * This function frees a directory list 69 */ 70 static void free_dirlist(struct dir_list **list) 71 { 72 struct dir_list *dp, *next; 73 74 for (dp = *list; dp; dp = next) { 75 next = dp->next; 76 free(dp->name); 77 free(dp); 78 } 79 *list = 0; 80 } 81 82 static int scan_dir(char *dirname, dev_t device, struct dir_list **list, 83 char **ret_path) 84 { 85 DIR *dir; 86 struct dirent *dp; 87 char path[1024], *cp; 88 int dirlen; 89 struct stat st; 90 91 dirlen = strlen(dirname); 92 if ((dir = opendir(dirname)) == NULL) 93 return errno; 94 dp = readdir(dir); 95 while (dp) { 96 if (dirlen + strlen(dp->d_name) + 2 >= sizeof(path)) 97 goto skip_to_next; 98 if (dp->d_name[0] == '.' && 99 ((dp->d_name[1] == 0) || 100 ((dp->d_name[1] == '.') && (dp->d_name[2] == 0)))) 101 goto skip_to_next; 102 sprintf(path, "%s/%s", dirname, dp->d_name); 103 if (stat(path, &st) < 0) 104 goto skip_to_next; 105 if (S_ISDIR(st.st_mode)) 106 add_to_dirlist(path, list); 107 if (ext2fsP_is_disk_device(st.st_mode) && 108 st.st_rdev == device) { 109 cp = malloc(strlen(path)+1); 110 if (!cp) { 111 closedir(dir); 112 return ENOMEM; 113 } 114 strcpy(cp, path); 115 *ret_path = cp; 116 goto success; 117 } 118 skip_to_next: 119 dp = readdir(dir); 120 } 121 success: 122 closedir(dir); 123 return 0; 124 } 125 126 /* 127 * This function finds the pathname to a block device with a given 128 * device number. It returns a pointer to allocated memory to the 129 * pathname on success, and NULL on failure. 130 */ 131 char *ext2fs_find_block_device(dev_t device) 132 { 133 struct dir_list *list = 0, *new_list = 0; 134 struct dir_list *current; 135 char *ret_path = 0; 136 int level = 0; 137 138 /* 139 * Add the starting directories to search... 140 */ 141 add_to_dirlist("/devices", &list); 142 add_to_dirlist("/devfs", &list); 143 add_to_dirlist("/dev", &list); 144 145 while (list) { 146 current = list; 147 list = list->next; 148 #ifdef DEBUG 149 printf("Scanning directory %s\n", current->name); 150 #endif 151 scan_dir(current->name, device, &new_list, &ret_path); 152 free(current->name); 153 free(current); 154 if (ret_path) 155 break; 156 /* 157 * If we're done checking at this level, descend to 158 * the next level of subdirectories. (breadth-first) 159 */ 160 if (list == 0) { 161 list = new_list; 162 new_list = 0; 163 /* Avoid infinite loop */ 164 if (++level >= EXT2FS_MAX_NESTED_LINKS) 165 break; 166 } 167 } 168 free_dirlist(&list); 169 free_dirlist(&new_list); 170 return ret_path; 171 } 172 173 174 #ifdef DEBUG 175 int main(int argc, char** argv) 176 { 177 char *devname, *tmp; 178 int major, minor; 179 dev_t device; 180 const char *errmsg = "Couldn't parse %s: %s\n"; 181 182 if ((argc != 2) && (argc != 3)) { 183 fprintf(stderr, "Usage: %s device_number\n", argv[0]); 184 fprintf(stderr, "\t: %s major minor\n", argv[0]); 185 exit(1); 186 } 187 if (argc == 2) { 188 device = strtoul(argv[1], &tmp, 0); 189 if (*tmp) { 190 fprintf(stderr, errmsg, "device number", argv[1]); 191 exit(1); 192 } 193 } else { 194 major = strtoul(argv[1], &tmp, 0); 195 if (*tmp) { 196 fprintf(stderr, errmsg, "major number", argv[1]); 197 exit(1); 198 } 199 minor = strtoul(argv[2], &tmp, 0); 200 if (*tmp) { 201 fprintf(stderr, errmsg, "minor number", argv[2]); 202 exit(1); 203 } 204 device = makedev(major, minor); 205 printf("Looking for device 0x%04x (%d:%d)\n", device, 206 major, minor); 207 } 208 devname = ext2fs_find_block_device(device); 209 if (devname) { 210 printf("Found device! %s\n", devname); 211 free(devname); 212 } else { 213 printf("Couldn't find device.\n"); 214 } 215 return 0; 216 } 217 218 #endif