читать /etc/mtab нет никакого смысла. уж лучше /proc/mounts.
Но более надежно посмотреть исходники udev.
Вот еще код из nash:| Код | /*
* taken from util-linux 2.11g and hacked into nash
*
* mount_by_label.c - aeb
*
* 1999-02-22 Arkadiusz Mi<B6>kiewicz <[email protected]>
* - added Native Language Support
* 2000-01-20 James Antill <[email protected]>
* - Added error message if /proc/partitions cannot be opened
* 2000-05-09 Erik Troan <[email protected]>
* - Added cache for UUID and disk labels
* 2000-11-07 Nathan Scott <[email protected]>
* - Added XFS support
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include "linux_fs.h"
#include "mount_by_label.h"
#define PROC_PARTITIONS "/proc/partitions"
#define DEVLABELDIR "/dev"
#define _(str) (str)
static struct uuidCache_s {
struct uuidCache_s *next;
char uuid[16];
char *device;
char *label;
int major, minor;
} *uuidCache = NULL;
typedef int (*GetLabelUuidProc)(int fd, char **label, char *uuid);
static int get_label_uuid_ext2(int fd, char **label, char *uuid);
static int get_label_uuid_xfs(int fd, char **label, char *uuid);
static int get_label_uuid_reiserfs(int fd, char **label, char *uuid);
/* for now, only ext2, ext3, reiserfs and xfs are supported */
static const
GetLabelUuidProc get_label_uuid_proc_table[] =
{
get_label_uuid_ext2,
get_label_uuid_reiserfs,
get_label_uuid_xfs,
NULL
};
static int
get_label_uuid_ext2(int fd, char **label, char *uuid)
{
struct ext2_super_block e2sb;
if ( ( lseek(fd, 1024, SEEK_SET) == 1024 )
&& read(fd, (char *) &e2sb, sizeof(e2sb)) == sizeof(e2sb)
&& (ext2magic(e2sb) == EXT2_SUPER_MAGIC)) {
size_t namesize;
memcpy(uuid, e2sb.s_uuid, sizeof(e2sb.s_uuid));
namesize = sizeof(e2sb.s_volume_name);
if ((*label = calloc(namesize + 1, 1)) != NULL)
memcpy(*label, e2sb.s_volume_name, namesize);
return 0;
}
return 1;
}
static int
get_label_uuid_xfs(int fd, char **label, char *uuid)
{
struct xfs_super_block xfsb;
if ( (lseek(fd, 0, SEEK_SET) == 0)
&& (read(fd, (char *) &xfsb, sizeof(xfsb)) == sizeof(xfsb) )
&& (strncmp((const char*)xfsb.s_magic, XFS_SUPER_MAGIC, 4) == 0) ) {
size_t namesize;
memcpy(uuid, xfsb.s_uuid, sizeof(xfsb.s_uuid));
namesize = sizeof(xfsb.s_fname);
if ((*label = calloc(namesize + 1, 1)) != NULL)
memcpy(*label, xfsb.s_fname, namesize);
return 0;
}
return 1;
}
static inline int reiserfs_magic_version(const char *magic)
{
int rc = 0;
if ( !strncmp(magic, REISERFS_SUPER_MAGIC_STRING, strlen(REISERFS_SUPER_MAGIC_STRING)) )
rc = 1;
if ( !strncmp(magic, REISER2FS_SUPER_MAGIC_STRING, strlen(REISER2FS_SUPER_MAGIC_STRING)) )
rc = 2;
if ( !strncmp(magic, REISER3FS_SUPER_MAGIC_STRING, strlen(REISER3FS_SUPER_MAGIC_STRING)) )
rc = 3;
return rc;
}
static int
get_label_uuid_reiserfs(int fd, char **label, char *uuid)
{
struct reiserfs_super_block reiserfssb;
if ( (lseek(fd, REISERFS_DISK_OFFSET_IN_BYTES, SEEK_SET) == REISERFS_DISK_OFFSET_IN_BYTES)
&& ( read(fd, (char *) &reiserfssb, sizeof(reiserfssb)) == sizeof(reiserfssb) )
/* Only 3.6.x format supers have labels or uuids.
Label and UUID can be set by reiserfstune -l/-u. */
&& (reiserfs_magic_version((const char*)reiserfssb.s_magic) > 1) ) {
size_t namesize;
memcpy(uuid, reiserfssb.s_uuid, sizeof(reiserfssb.s_uuid));
namesize = sizeof(reiserfssb.s_label);
if ((*label = calloc(namesize + 1, 1)) != NULL)
memcpy(*label, reiserfssb.s_label, namesize);
return 0;
}
return 1;
}
static int
get_label_uuid(const char *device, char **label, char *uuid)
{
int fd;
int rv = 1;
const GetLabelUuidProc *proc = get_label_uuid_proc_table;
fd = open(device, O_RDONLY);
if (fd < 0)
return rv;
while(*proc) {
rv = (*proc)(fd, label, uuid);
if ( !rv )
break;
++proc;
}
close(fd);
return rv;
}
static void
uuidcache_addentry(char * device, int major, int minor, char *label, char *uuid) {
struct uuidCache_s *last;
if (!uuidCache) {
last = uuidCache = malloc(sizeof(*uuidCache));
} else {
for (last = uuidCache; last->next; last = last->next) ;
last->next = malloc(sizeof(*uuidCache));
last = last->next;
}
last->next = NULL;
last->label = label;
last->device = device;
last->major = major;
last->minor = minor;
memcpy(last->uuid, uuid, sizeof(last->uuid));
}
static void
uuidcache_init(void) {
char line[100];
char *s;
int ma, mi, sz;
static char ptname[100];
FILE *procpt;
char uuid[16], *label;
char device[110];
int firstPass;
int handleOnFirst;
char * chptr, * endptr;
if (uuidCache)
return;
procpt = fopen(PROC_PARTITIONS, "r");
if (!procpt) {
static int warn = 0;
if (!warn++)
fprintf (stderr, _("mount: could not open %s, so UUID and LABEL "
"conversion cannot be done.\n"),
PROC_PARTITIONS);
return;
}
for (firstPass = 1; firstPass >= 0; firstPass--) {
fseek(procpt, 0, SEEK_SET);
while (fgets(line, sizeof(line), procpt)) {
/* The original version of this code used sscanf, but
diet's sscanf is quite limited */
chptr = line;
if (*chptr++ != ' ') continue;
ma = strtol(chptr, &endptr, 0);
if (endptr == chptr) continue;
while (isspace(*endptr)) endptr++;
chptr = endptr;
mi = strtol(chptr, &endptr, 0);
if (endptr == chptr) continue;
while (isspace(*endptr)) endptr++;
chptr = endptr;
sz = strtol(chptr, &endptr, 0);
if (endptr == chptr) continue;
while (isspace(*endptr)) endptr++;
chptr = endptr;
while (!isspace(*endptr) && *endptr != '\n') endptr++;
if (chptr == endptr) continue;
strncpy(ptname, chptr, endptr - chptr);
ptname[endptr - chptr] = '\0';
/* skip extended partitions (heuristic: size 1) */
if (sz == 1)
continue;
/* look only at md devices on first pass */
handleOnFirst = !strncmp(ptname, "md", 2);
if (firstPass != handleOnFirst)
continue;
/* skip entire disk (minor 0, 64, ... on ide;
0, 16, ... on sd) */
/* heuristic: partition name ends in a digit */
for(s = ptname; *s; s++);
if (isdigit(s[-1])) {
char * ptr;
char * deviceDir = NULL;
int mustRemove = 0;
int mustRemoveDir = 0;
int i;
snprintf(device, 110, "%s/%s", DEVLABELDIR, ptname);
if (access(device, F_OK)) {
ptr = device;
i = 0;
while (*ptr)
if (*ptr++ == '/')
i++;
if (i > 2) {
deviceDir = alloca(strlen(device) + 1);
strcpy(deviceDir, device);
ptr = deviceDir + (strlen(device) - 1);
while (*ptr != '/')
*ptr-- = '\0';
if (mkdir(deviceDir, 0644)) {
printf("mkdir: cannot create directory %s: %d\n", deviceDir, errno);
} else {
mustRemoveDir = 1;
}
}
mknod(device, S_IFBLK | 0600, makedev(ma, mi));
mustRemove = 1;
}
if (!get_label_uuid(device, &label, uuid))
uuidcache_addentry(strdup(device), ma, mi,
label, uuid);
if (mustRemove) unlink(device);
if (mustRemoveDir) rmdir(deviceDir);
}
}
}
fclose(procpt);
}
#define UUID 1
#define VOL 2
static char *
get_spec_by_x(int n, const char *t, int * majorPtr, int * minorPtr) {
struct uuidCache_s *uc;
uuidcache_init();
uc = uuidCache;
while(uc) {
switch (n) {
case UUID:
if (!memcmp(t, uc->uuid, sizeof(uc->uuid))) {
*majorPtr = uc->major;
*minorPtr = uc->minor;
return uc->device;
}
break;
case VOL:
if (!strcmp(t, uc->label)) {
*majorPtr = uc->major;
*minorPtr = uc->minor;
return uc->device;
}
break;
}
uc = uc->next;
}
return NULL;
}
static unsigned char
fromhex(char c) {
if (isdigit(c))
return (c - '0');
else if (islower(c))
return (c - 'a' + 10);
else
return (c - 'A' + 10);
}
char *
get_spec_by_uuid(const char *s, int * major, int * minor) {
unsigned char uuid[16];
int i;
if (strlen(s) != 36 ||
s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-')
goto bad_uuid;
for (i=0; i<16; i++) {
if (*s == '-') s++;
if (!isxdigit(s[0]) || !isxdigit(s[1]))
goto bad_uuid;
uuid[i] = ((fromhex(s[0])<<4) | fromhex(s[1]));
s += 2;
}
return get_spec_by_x(UUID, (const char*)uuid, major, minor);
bad_uuid:
fprintf(stderr, _("mount: bad UUID"));
return 0;
}
char *
get_spec_by_volume_label(const char *s, int * major, int * minor) {
return get_spec_by_x(VOL, s, major, minor);
}
int display_uuid_cache(void) {
struct uuidCache_s * u;
size_t i;
uuidcache_init();
u = uuidCache;
while (u) {
printf("%s %s ", u->device, u->label);
for (i = 0; i < sizeof(u->uuid); i++) {
if (i == 4 || i == 6 || i == 8 || i == 10)
printf("-");
printf("%x", u->uuid[i] & 0xff);
}
printf("\n");
u = u->next;
}
return 0;
} |
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