diff options
Diffstat (limited to 'bylabel.c')
| -rw-r--r-- | bylabel.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/bylabel.c b/bylabel.c new file mode 100644 index 0000000..3ce77b2 --- /dev/null +++ b/bylabel.c @@ -0,0 +1,256 @@ +/* + * Derived from the util-linux/mount/mount_by_label.c source, + * currently maintained by Andries Brouwer <aeb@cwi.nl>. + * + * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org> + * - added Native Language Support + * 2000-01-20 James Antill <james@and.org> + * - Added error message if /proc/partitions cannot be opened + * 2000-05-09 Erik Troan <ewt@redhat.com> + * - Added cache for UUID and disk labels + * 2000-11-07 Nathan Scott <nathans@sgi.com> + * - Added XFS support + */ + +#include <stdio.h> +#include <sys/param.h> +#include <string.h> +#include <ctype.h> +#include <fcntl.h> +#include <unistd.h> + +#include "bylabel.h" +#include "common.h" +#include "pot.h" + +#define PROC_PARTITIONS "/proc/partitions" +#define DEVLABELDIR "/dev" + +static struct uuidCache_s { + struct uuidCache_s *next; + char uuid[16]; + char *label; + char *device; +} *uuidCache = NULL; + +#define EXT2_SUPER_MAGIC 0xEF53 +struct ext2_super_block { + u_char s_dummy1[56]; + u_char s_magic[2]; + u_char s_dummy2[46]; + u_char s_uuid[16]; + u_char s_volume_name[16]; +}; + +#define ext2magic(s) ((uint) s.s_magic[0] + (((uint) s.s_magic[1]) << 8)) + +#define XFS_SUPER_MAGIC "XFSB" +#define XFS_SUPER_MAGIC2 "BSFX" +struct xfs_super_block { + u_char s_magic[4]; + u_char s_dummy[28]; + u_char s_uuid[16]; + u_char s_dummy2[60]; + u_char s_fsname[12]; +}; + +static inline unsigned short swapped(unsigned short a) +{ + return (a >> 8) | (a << 8); +} + +/* for now, only ext2 and xfs are supported */ +static int get_label_uuid(const char *device, char **label, char *uuid) +{ + + /* start with ext2 and xfs tests, taken from mount_guess_fstype */ + /* should merge these later */ + int fd; + int rv = 1; + size_t namesize; + struct ext2_super_block e2sb; + struct xfs_super_block xfsb; + + fd = open(device, O_RDONLY); + if (fd < 0) + return rv; + + if (lseek(fd, 1024, SEEK_SET) == 1024 + && read(fd, (char *)&e2sb, sizeof(e2sb)) == sizeof(e2sb) + && ext2magic(e2sb) == EXT2_SUPER_MAGIC) { + memcpy(uuid, e2sb.s_uuid, sizeof(e2sb.s_uuid)); + namesize = sizeof(e2sb.s_volume_name); + *label = smalloc(namesize + 1); + sstrncpy(*label, e2sb.s_volume_name, namesize); + rv = 0; + } + else if (lseek(fd, 0, SEEK_SET) == 0 + && read(fd, (char *)&xfsb, sizeof(xfsb)) == sizeof(xfsb) + && (strncmp((char *)&xfsb.s_magic, XFS_SUPER_MAGIC, 4) == 0 || + strncmp((char *)&xfsb.s_magic, XFS_SUPER_MAGIC2, 4) == 0)) { + memcpy(uuid, xfsb.s_uuid, sizeof(xfsb.s_uuid)); + namesize = sizeof(xfsb.s_fsname); + *label = smalloc(namesize + 1); + sstrncpy(*label, xfsb.s_fsname, namesize); + rv = 0; + } + + close(fd); + return rv; +} + +static void uuidcache_addentry(char *device, char *label, char *uuid) +{ + struct uuidCache_s *last; + + if (!uuidCache) { + last = uuidCache = smalloc(sizeof(*uuidCache)); + } + else { + for (last = uuidCache; last->next; last = last->next); + last->next = smalloc(sizeof(*uuidCache)); + last = last->next; + } + last->next = NULL; + last->device = device; + last->label = label; + 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; + + if (uuidCache) + return; + + procpt = fopen(PROC_PARTITIONS, "r"); + if (!procpt) + return; + + for (firstPass = 1; firstPass >= 0; firstPass--) { + fseek(procpt, 0, SEEK_SET); + + while (fgets(line, sizeof(line), procpt)) { + if (sscanf(line, " %d %d %d %[^\n ]", &ma, &mi, &sz, ptname) != 4) + continue; + + /* 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])) { + /* + * Note: this is a heuristic only - there is no reason + * why these devices should live in /dev. + * Perhaps this directory should be specifiable by option. + * One might for example have /devlabel with links to /dev + * for the devices that may be accessed in this way. + * (This is useful, if the cdrom on /dev/hdc must not + * be accessed.) + */ + sprintf(device, "%s/%s", DEVLABELDIR, ptname); + if (!get_label_uuid(device, &label, uuid)) + uuidcache_addentry(sstrdup(device), label, uuid); + } + } + } + + fclose(procpt); +} + +#define UUID 1 +#define VOL 2 + +static char *get_spec_by_x(int n, const char *t) +{ + struct uuidCache_s *uc; + + uuidcache_init(); + uc = uuidCache; + + while (uc) { + switch (n) { + case UUID: + if (!memcmp(t, uc->uuid, sizeof(uc->uuid))) + return sstrdup(uc->device); + break; + case VOL: + if (!strcmp(t, uc->label)) + return sstrdup(uc->device); + break; + } + uc = uc->next; + } + return NULL; +} + +static u_char fromhex(char c) +{ + if (isdigit(c)) + return (c - '0'); + else if (islower(c)) + return (c - 'a' + 10); + else + return (c - 'A' + 10); +} + +static char *get_spec_by_uuid(const char *s) +{ + u_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, uuid); + + bad_uuid: + fprintf(stderr, _("Found an invalid UUID: %s\n"), s); + return NULL; +} + +static char *get_spec_by_volume_label(const char *s) +{ + return get_spec_by_x(VOL, s); +} + +const char *get_device_name(const char *item) +{ + const char *rc; + + if (!strncmp(item, "UUID=", 5)) + rc = get_spec_by_uuid(item + 5); + else if (!strncmp(item, "LABEL=", 6)) + rc = get_spec_by_volume_label(item + 6); + else + rc = sstrdup(item); + if (!rc) + fprintf(stderr, _("Error checking device name: %s\n"), item); + return rc; +} |