2 * mount_by_label.c - aeb
4 * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
5 * - added Native Language Support
6 * 2000-01-20 James Antill <james@and.org>
7 * - Added error message if /proc/partitions cannot be opened
8 * 2000-05-09 Erik Troan <ewt@redhat.com>
9 * - Added cache for UUID and disk labels
10 * Wed Aug 16 2000 Erik Troan <ewt@redhat.com>
11 * - Ported to dump/restore
15 #include <compatlfs.h>
16 #include <sys/types.h>
18 #include <sys/param.h>
24 #include <sys/cdefs.h>
29 #define PROC_PARTITIONS "/proc/partitions"
30 #define DEVLABELDIR "/dev"
32 #define EXT2_SUPER_OFFSET 1024
33 #define EXT2_SUPER_SIZE sizeof(struct ext2_super_block)
34 #define EXT2_SUPER_MAGIC 0xEF53
38 struct ext2_super_block {
39 unsigned char s_dummy1[56];
40 unsigned char s_magic[2];
41 unsigned char s_dummy2[46];
42 unsigned char s_uuid[16];
43 unsigned char s_volume_name[VOLNAMSZ];
45 #define ext2magic(s) ((unsigned int) s.s_magic[0] + (((unsigned int) s.s_magic[1]) << 8))
47 void msg __P((const char *fmt, ...));
49 static struct uuidCache_s {
50 struct uuidCache_s *next;
56 /* for now, only ext2 is supported */
58 get_label_uuid(const char *device, char **label, char *uuid) {
60 /* start with a test for ext2, taken from mount_guess_fstype */
61 /* should merge these later */
63 struct ext2_super_block e2sb;
65 fd = OPEN(device, O_RDONLY);
69 if (LSEEK(fd, EXT2_SUPER_OFFSET, SEEK_SET) != EXT2_SUPER_OFFSET ||
70 read(fd, (char *) &e2sb, EXT2_SUPER_SIZE) != EXT2_SUPER_SIZE ||
71 ext2magic(e2sb) != EXT2_SUPER_MAGIC) {
78 /* superblock is ext2 - now what is its label? */
79 memcpy(uuid, e2sb.s_uuid, sizeof(e2sb.s_uuid));
80 *label = malloc(VOLNAMSZ + 1);
81 strncpy(*label, e2sb.s_volume_name, VOLNAMSZ);
82 (*label)[VOLNAMSZ] = 0;
88 uuidcache_addentry(char *device, char *label, char *uuid) {
89 struct uuidCache_s *last;
92 last = uuidCache = (struct uuidCache_s *)malloc(sizeof(*uuidCache));
94 for (last = uuidCache; last->next; last = last->next) ;
95 last->next = (struct uuidCache_s *)malloc(sizeof(*uuidCache));
99 last->device = device;
101 memcpy(last->uuid, uuid, sizeof(last->uuid));
105 uuidcache_init(void) {
109 static char ptname[100];
111 char uuid[16], *label;
119 procpt = fopen(PROC_PARTITIONS, "r");
123 for (firstPass = 1; firstPass >= 0; firstPass--) {
124 fseek(procpt, 0, SEEK_SET);
126 while (fgets(line, sizeof(line), procpt)) {
127 if (sscanf (line, " %d %d %d %[^\n ]",
128 &ma, &mi, &sz, ptname) != 4)
131 /* skip extended partitions (heuristic: size 1) */
135 /* look only at md devices on first pass */
136 handleOnFirst = !strncmp(ptname, "md", 2);
137 if (firstPass != handleOnFirst)
140 /* skip entire disk (minor 0, 64, ... on ide;
142 /* heuristic: partition name ends in a digit */
144 for(s = ptname; *s; s++);
145 if (isdigit(s[-1])) {
147 * Note: this is a heuristic only - there is no reason
148 * why these devices should live in /dev.
149 * Perhaps this directory should be specifiable by option.
150 * One might for example have /devlabel with links to /dev
151 * for the devices that may be accessed in this way.
152 * (This is useful, if the cdrom on /dev/hdc must not
155 sprintf(device, "%s/%s", DEVLABELDIR, ptname);
156 if (!get_label_uuid(device, &label, uuid))
157 uuidcache_addentry(strdup(device), label, uuid);
169 get_spec_by_x(int n, const char *t) {
170 struct uuidCache_s *uc;
178 if (!memcmp(t, uc->uuid, sizeof(uc->uuid)))
179 return strdup(uc->device);
182 if (!strcmp(t, uc->label))
183 return strdup(uc->device);
196 return (c - 'a' + 10);
198 return (c - 'A' + 10);
202 get_spec_by_uuid(const char *s) {
206 if (strlen(s) != 36 ||
207 s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-')
209 for (i=0; i<16; i++) {
211 if (!isxdigit(s[0]) || !isxdigit(s[1]))
213 uuid[i] = ((fromhex(s[0])<<4) | fromhex(s[1]));
216 return get_spec_by_x(UUID, uuid);
219 msg("mount: bad UUID\n");
220 return NULL; /* just for gcc */
224 get_spec_by_volume_label(const char *s) {
225 return get_spec_by_x(VOL, s);
229 get_device_name(const char * item) {
232 if (!strncmp(item, "UUID=", 5)) {
233 rc = get_spec_by_uuid(item+5);
236 if (!strncmp(item, "LABEL=", 6)) {
237 rc = get_spec_by_volume_label(item+6);
247 get_device_label(const char * spec) {
248 struct uuidCache_s *uc;
254 if (!strcmp(spec, uc->device))
255 return uc->label[0] == '\0' ? NULL : strdup(uc->label);
261 #endif /* !HAVE_BLKID */