paul@181 | 1 | /* |
paul@181 | 2 | * devno.c - find a particular device by its device number (major/minor) |
paul@181 | 3 | * |
paul@181 | 4 | * Copyright (C) 2000, 2001, 2003 Theodore Ts'o |
paul@181 | 5 | * Copyright (C) 2001 Andreas Dilger |
paul@181 | 6 | * |
paul@181 | 7 | * %Begin-Header% |
paul@181 | 8 | * This file may be redistributed under the terms of the |
paul@181 | 9 | * GNU Lesser General Public License. |
paul@181 | 10 | * %End-Header% |
paul@181 | 11 | */ |
paul@181 | 12 | |
paul@181 | 13 | #include "config.h" |
paul@181 | 14 | #include <stdio.h> |
paul@181 | 15 | #include <string.h> |
paul@181 | 16 | #if HAVE_UNISTD_H |
paul@181 | 17 | #include <unistd.h> |
paul@181 | 18 | #endif |
paul@181 | 19 | #include <stdlib.h> |
paul@181 | 20 | #include <string.h> |
paul@181 | 21 | #if HAVE_SYS_TYPES_H |
paul@181 | 22 | #include <sys/types.h> |
paul@181 | 23 | #endif |
paul@181 | 24 | #if HAVE_SYS_STAT_H |
paul@181 | 25 | #include <sys/stat.h> |
paul@181 | 26 | #endif |
paul@181 | 27 | #include <dirent.h> |
paul@181 | 28 | #if HAVE_ERRNO_H |
paul@181 | 29 | #include <errno.h> |
paul@181 | 30 | #endif |
paul@181 | 31 | #if HAVE_SYS_MKDEV_H |
paul@181 | 32 | #include <sys/mkdev.h> |
paul@181 | 33 | #endif |
paul@181 | 34 | #ifdef HAVE_SYS_SYSMACROS_H |
paul@181 | 35 | #include <sys/sysmacros.h> |
paul@181 | 36 | #endif |
paul@181 | 37 | |
paul@181 | 38 | #include "blkidP.h" |
paul@181 | 39 | |
paul@181 | 40 | char *blkid_strndup(const char *s, int length) |
paul@181 | 41 | { |
paul@181 | 42 | char *ret; |
paul@181 | 43 | |
paul@181 | 44 | if (!s) |
paul@181 | 45 | return NULL; |
paul@181 | 46 | |
paul@181 | 47 | if (!length) |
paul@181 | 48 | length = strlen(s); |
paul@181 | 49 | |
paul@181 | 50 | ret = malloc(length + 1); |
paul@181 | 51 | if (ret) { |
paul@181 | 52 | strncpy(ret, s, length); |
paul@181 | 53 | ret[length] = '\0'; |
paul@181 | 54 | } |
paul@181 | 55 | return ret; |
paul@181 | 56 | } |
paul@181 | 57 | |
paul@181 | 58 | char *blkid_strdup(const char *s) |
paul@181 | 59 | { |
paul@181 | 60 | return blkid_strndup(s, 0); |
paul@181 | 61 | } |
paul@181 | 62 | |
paul@181 | 63 | /* |
paul@181 | 64 | * This function adds an entry to the directory list |
paul@181 | 65 | */ |
paul@181 | 66 | static void add_to_dirlist(const char *name, struct dir_list **list) |
paul@181 | 67 | { |
paul@181 | 68 | struct dir_list *dp; |
paul@181 | 69 | |
paul@181 | 70 | dp = malloc(sizeof(struct dir_list)); |
paul@181 | 71 | if (!dp) |
paul@181 | 72 | return; |
paul@181 | 73 | dp->name = blkid_strdup(name); |
paul@181 | 74 | if (!dp->name) { |
paul@181 | 75 | free(dp); |
paul@181 | 76 | return; |
paul@181 | 77 | } |
paul@181 | 78 | dp->next = *list; |
paul@181 | 79 | *list = dp; |
paul@181 | 80 | } |
paul@181 | 81 | |
paul@181 | 82 | /* |
paul@181 | 83 | * This function frees a directory list |
paul@181 | 84 | */ |
paul@181 | 85 | static void free_dirlist(struct dir_list **list) |
paul@181 | 86 | { |
paul@181 | 87 | struct dir_list *dp, *next; |
paul@181 | 88 | |
paul@181 | 89 | for (dp = *list; dp; dp = next) { |
paul@181 | 90 | next = dp->next; |
paul@181 | 91 | free(dp->name); |
paul@181 | 92 | free(dp); |
paul@181 | 93 | } |
paul@181 | 94 | *list = NULL; |
paul@181 | 95 | } |
paul@181 | 96 | |
paul@181 | 97 | void blkid__scan_dir(const char *dirname, dev_t devno, struct dir_list **list, |
paul@181 | 98 | char **devname) |
paul@181 | 99 | { |
paul@181 | 100 | DIR *dir; |
paul@181 | 101 | struct dirent *dp; |
paul@181 | 102 | char path[1024]; |
paul@181 | 103 | int dirlen; |
paul@181 | 104 | struct stat st; |
paul@181 | 105 | |
paul@181 | 106 | if ((dir = opendir(dirname)) == NULL) |
paul@181 | 107 | return; |
paul@181 | 108 | dirlen = strlen(dirname) + 2; |
paul@181 | 109 | while ((dp = readdir(dir)) != 0) { |
paul@181 | 110 | if (dirlen + strlen(dp->d_name) >= sizeof(path)) |
paul@181 | 111 | continue; |
paul@181 | 112 | |
paul@181 | 113 | if (dp->d_name[0] == '.' && |
paul@181 | 114 | ((dp->d_name[1] == 0) || |
paul@181 | 115 | ((dp->d_name[1] == '.') && (dp->d_name[2] == 0)))) |
paul@181 | 116 | continue; |
paul@181 | 117 | |
paul@181 | 118 | sprintf(path, "%s/%s", dirname, dp->d_name); |
paul@181 | 119 | if (stat(path, &st) < 0) |
paul@181 | 120 | continue; |
paul@181 | 121 | |
paul@181 | 122 | if (blkidP_is_disk_device(st.st_mode) && st.st_rdev == devno) { |
paul@181 | 123 | *devname = blkid_strdup(path); |
paul@181 | 124 | DBG(DEBUG_DEVNO, |
paul@181 | 125 | printf("found 0x%llx at %s (%p)\n", (long long)devno, |
paul@181 | 126 | path, *devname)); |
paul@181 | 127 | break; |
paul@181 | 128 | } |
paul@181 | 129 | if (list && S_ISDIR(st.st_mode) && !lstat(path, &st) && |
paul@181 | 130 | S_ISDIR(st.st_mode)) |
paul@181 | 131 | add_to_dirlist(path, list); |
paul@181 | 132 | } |
paul@181 | 133 | closedir(dir); |
paul@181 | 134 | return; |
paul@181 | 135 | } |
paul@181 | 136 | |
paul@181 | 137 | /* Directories where we will try to search for device numbers */ |
paul@181 | 138 | static const char *devdirs[] = { "/devices", "/devfs", "/dev", NULL }; |
paul@181 | 139 | |
paul@181 | 140 | /* |
paul@181 | 141 | * This function finds the pathname to a block device with a given |
paul@181 | 142 | * device number. It returns a pointer to allocated memory to the |
paul@181 | 143 | * pathname on success, and NULL on failure. |
paul@181 | 144 | */ |
paul@181 | 145 | char *blkid_devno_to_devname(dev_t devno) |
paul@181 | 146 | { |
paul@181 | 147 | struct dir_list *list = NULL, *new_list = NULL; |
paul@181 | 148 | char *devname = NULL; |
paul@181 | 149 | const char **dir; |
paul@181 | 150 | |
paul@181 | 151 | /* |
paul@181 | 152 | * Add the starting directories to search in reverse order of |
paul@181 | 153 | * importance, since we are using a stack... |
paul@181 | 154 | */ |
paul@181 | 155 | for (dir = devdirs; *dir; dir++) |
paul@181 | 156 | add_to_dirlist(*dir, &list); |
paul@181 | 157 | |
paul@181 | 158 | while (list) { |
paul@181 | 159 | struct dir_list *current = list; |
paul@181 | 160 | |
paul@181 | 161 | list = list->next; |
paul@181 | 162 | DBG(DEBUG_DEVNO, printf("directory %s\n", current->name)); |
paul@181 | 163 | blkid__scan_dir(current->name, devno, &new_list, &devname); |
paul@181 | 164 | free(current->name); |
paul@181 | 165 | free(current); |
paul@181 | 166 | if (devname) |
paul@181 | 167 | break; |
paul@181 | 168 | /* |
paul@181 | 169 | * If we're done checking at this level, descend to |
paul@181 | 170 | * the next level of subdirectories. (breadth-first) |
paul@181 | 171 | */ |
paul@181 | 172 | if (list == NULL) { |
paul@181 | 173 | list = new_list; |
paul@181 | 174 | new_list = NULL; |
paul@181 | 175 | } |
paul@181 | 176 | } |
paul@181 | 177 | free_dirlist(&list); |
paul@181 | 178 | free_dirlist(&new_list); |
paul@181 | 179 | |
paul@181 | 180 | if (!devname) { |
paul@181 | 181 | DBG(DEBUG_DEVNO, |
paul@181 | 182 | printf("blkid: couldn't find devno 0x%04lx\n", |
paul@181 | 183 | (unsigned long) devno)); |
paul@181 | 184 | } else { |
paul@181 | 185 | DBG(DEBUG_DEVNO, |
paul@181 | 186 | printf("found devno 0x%04llx as %s\n", (long long)devno, devname)); |
paul@181 | 187 | } |
paul@181 | 188 | |
paul@181 | 189 | |
paul@181 | 190 | return devname; |
paul@181 | 191 | } |
paul@181 | 192 | |
paul@181 | 193 | #ifdef TEST_PROGRAM |
paul@181 | 194 | int main(int argc, char** argv) |
paul@181 | 195 | { |
paul@181 | 196 | char *devname, *tmp; |
paul@181 | 197 | int major, minor; |
paul@181 | 198 | dev_t devno; |
paul@181 | 199 | const char *errmsg = "Couldn't parse %s: %s\n"; |
paul@181 | 200 | |
paul@181 | 201 | blkid_debug_mask = DEBUG_ALL; |
paul@181 | 202 | if ((argc != 2) && (argc != 3)) { |
paul@181 | 203 | fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n" |
paul@181 | 204 | "Resolve a device number to a device name\n", |
paul@181 | 205 | argv[0], argv[0]); |
paul@181 | 206 | exit(1); |
paul@181 | 207 | } |
paul@181 | 208 | if (argc == 2) { |
paul@181 | 209 | devno = strtoul(argv[1], &tmp, 0); |
paul@181 | 210 | if (*tmp) { |
paul@181 | 211 | fprintf(stderr, errmsg, "device number", argv[1]); |
paul@181 | 212 | exit(1); |
paul@181 | 213 | } |
paul@181 | 214 | } else { |
paul@181 | 215 | major = strtoul(argv[1], &tmp, 0); |
paul@181 | 216 | if (*tmp) { |
paul@181 | 217 | fprintf(stderr, errmsg, "major number", argv[1]); |
paul@181 | 218 | exit(1); |
paul@181 | 219 | } |
paul@181 | 220 | minor = strtoul(argv[2], &tmp, 0); |
paul@181 | 221 | if (*tmp) { |
paul@181 | 222 | fprintf(stderr, errmsg, "minor number", argv[2]); |
paul@181 | 223 | exit(1); |
paul@181 | 224 | } |
paul@181 | 225 | devno = makedev(major, minor); |
paul@181 | 226 | } |
paul@181 | 227 | printf("Looking for device 0x%04llx\n", (long long)devno); |
paul@181 | 228 | devname = blkid_devno_to_devname(devno); |
paul@181 | 229 | free(devname); |
paul@181 | 230 | return 0; |
paul@181 | 231 | } |
paul@181 | 232 | #endif |