/* vi: set sw=4 ts=4: */
/*
 * Support functions for mounting devices by label/uuid
 *
 * Copyright (C) 2006 by Jason Schoon <floydpink@gmail.com>
 * Some portions cribbed from e2fsprogs, util-linux, dosfstools
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

//kbuild:lib-$(CONFIG_BLKID) += get_devname.o
//kbuild:lib-$(CONFIG_FINDFS) += get_devname.o
//kbuild:lib-$(CONFIG_FEATURE_MOUNT_LABEL) += get_devname.o

#include <sys/mount.h> /* BLKGETSIZE64 */
#if !defined(BLKGETSIZE64)
# define BLKGETSIZE64 _IOR(0x12,114,size_t)
#endif
#include "volume_id_internal.h"

static struct uuidCache_s {
        struct uuidCache_s *next;
//      int major, minor;
        char *device;
        char *label;
        char *uc_uuid; /* prefix makes it easier to grep for */
        IF_FEATURE_BLKID_TYPE(const char *type;)
} *uuidCache;

#if !ENABLE_FEATURE_BLKID_TYPE
#define get_label_uuid(fd, label, uuid, type) \
        get_label_uuid(fd, label, uuid)
#define uuidcache_addentry(device, label, uuid, type) \
        uuidcache_addentry(device, label, uuid)
#endif

/* Returns !0 on error.
 * Otherwise, returns malloc'ed strings for label and uuid
 * (and they can't be NULL, although they can be "").
 * NB: closes fd. */
static int
get_label_uuid(int fd, char **label, char **uuid, const char **type)
{
        int rv = 1;
        uint64_t size;
        struct volume_id *vid;

        /* fd is owned by vid now */
        vid = volume_id_open_node(fd);

        if (ioctl(/*vid->*/fd, BLKGETSIZE64, &size) != 0)
                size = 0;

        if (volume_id_probe_all(vid, /*0,*/ size) != 0)
                goto ret;

        if (vid->label[0] != '\0' || vid->uuid[0] != '\0'
#if ENABLE_FEATURE_BLKID_TYPE
         || vid->type != NULL
#endif
        ) {
                *label = xstrndup(vid->label, sizeof(vid->label));
                *uuid  = xstrndup(vid->uuid, sizeof(vid->uuid));
#if ENABLE_FEATURE_BLKID_TYPE
                *type = vid->type;
                dbg("found label '%s', uuid '%s', type '%s'", *label, *uuid, *type);
#else
                dbg("found label '%s', uuid '%s'", *label, *uuid);
#endif
                rv = 0;
        }
 ret:
        free_volume_id(vid); /* also closes fd */
        return rv;
}

/* NB: we take ownership of (malloc'ed) label and uuid */
static void
uuidcache_addentry(char *device, /*int major, int minor,*/ char *label, char *uuid, const char *type)
{
        struct uuidCache_s *last;

        if (!uuidCache) {
                last = uuidCache = xzalloc(sizeof(*uuidCache));
        } else {
                for (last = uuidCache; last->next; last = last->next)
                        continue;
                last->next = xzalloc(sizeof(*uuidCache));
                last = last->next;
        }
        /*last->next = NULL; - xzalloc did it*/
//      last->major = major;
//      last->minor = minor;
        last->device = device;
        last->label = label;
        last->uc_uuid = uuid;
        IF_FEATURE_BLKID_TYPE(last->type = type;)
}

/* If get_label_uuid() on device_name returns success,
 * add a cache entry for this device.
 * If device node does not exist, it will be temporarily created. */
static int FAST_FUNC
uuidcache_check_device(const char *device,
                struct stat *statbuf,
                void *userData UNUSED_PARAM,
                int depth UNUSED_PARAM)
{
        /* note: this check rejects links to devices, among other nodes */
        if (!S_ISBLK(statbuf->st_mode))
                return TRUE;

        /* Users report that mucking with floppies (especially non-present
         * ones) is significant PITA. This is a horribly dirty hack,
         * but it is very useful in real world.
         * If this will ever need to be enabled, consider using O_NONBLOCK.
         */
        if (major(statbuf->st_rdev) == 2)
                return TRUE;

        add_to_uuid_cache(device);

        return TRUE;
}

static struct uuidCache_s*
uuidcache_init(int scan_devices)
{
        dbg("DBG: uuidCache=%x, uuidCache");
        if (uuidCache)
                return uuidCache;

        /* We were scanning /proc/partitions
         * and /proc/sys/dev/cdrom/info here.
         * Missed volume managers. I see that "standard" blkid uses these:
         * /dev/mapper/control
         * /proc/devices
         * /proc/evms/volumes
         * /proc/lvm/VGs
         * This is unacceptably complex. Let's just scan /dev.
         * (Maybe add scanning of /sys/block/XXX/dev for devices
         * somehow not having their /dev/XXX entries created?) */
        if (scan_devices)
                recursive_action("/dev", ACTION_RECURSE,
                        uuidcache_check_device, /* file_action */
                        NULL, /* dir_action */
                        NULL, /* userData */
                        0 /* depth */);

        return uuidCache;
}

#define UUID   1
#define VOL    2

#ifdef UNUSED
static char *
get_spec_by_x(int n, const char *t, int *majorPtr, int *minorPtr)
{
        struct uuidCache_s *uc;

        uc = uuidcache_init(/*scan_devices:*/ 1);
        while (uc) {
                switch (n) {
                case UUID:
                        if (strcmp(t, uc->uc_uuid) == 0) {
                                *majorPtr = uc->major;
                                *minorPtr = uc->minor;
                                return uc->device;
                        }
                        break;
                case VOL:
                        if (strcmp(t, uc->label) == 0) {
                                *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');
        return ((c|0x20) - 'a' + 10);
}

static 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, (char *)uuid, major, minor);

 bad_uuid:
        fprintf(stderr, _("mount: bad UUID"));
        return 0;
}

static char *
get_spec_by_volume_label(const char *s, int *major, int *minor)
{
        return get_spec_by_x(VOL, s, major, minor);
}
#endif // UNUSED

/* Used by blkid */
void display_uuid_cache(int scan_devices)
{
        struct uuidCache_s *uc;

        uc = uuidcache_init(scan_devices);
        while (uc) {
                printf("%s:", uc->device);
                if (uc->label[0])
                        printf(" LABEL=\"%s\"", uc->label);
                if (uc->uc_uuid[0])
                        printf(" UUID=\"%s\"", uc->uc_uuid);
#if ENABLE_FEATURE_BLKID_TYPE
        if (uc->type)
                printf(" TYPE=\"%s\"", uc->type);
#endif
                bb_putchar('\n');
                uc = uc->next;
        }
}

int add_to_uuid_cache(const char *device)
{
        char *uuid = uuid; /* for compiler */
        char *label = label;
#if ENABLE_FEATURE_BLKID_TYPE
        const char *type = type;
#endif
        int fd;

        fd = open(device, O_RDONLY);
        if (fd < 0)
                return 0;

        /* get_label_uuid() closes fd in all cases (success & failure) */
        if (get_label_uuid(fd, &label, &uuid, &type) == 0) {
                /* uuidcache_addentry() takes ownership of all four params */
                uuidcache_addentry(xstrdup(device), /*ma, mi,*/ label, uuid, type);
                return 1;
        }
        return 0;
}


/* Used by mount and findfs */

char *get_devname_from_label(const char *spec)
{
        struct uuidCache_s *uc;

        uc = uuidcache_init(/*scan_devices:*/ 1);
        while (uc) {
                if (uc->label[0] && strcmp(spec, uc->label) == 0) {
                        return xstrdup(uc->device);
                }
                uc = uc->next;
        }
        return NULL;
}

char *get_devname_from_uuid(const char *spec)
{
        struct uuidCache_s *uc;

        uc = uuidcache_init(/*scan_devices:*/ 1);
        while (uc) {
                /* case of hex numbers doesn't matter */
                if (strcasecmp(spec, uc->uc_uuid) == 0) {
                        return xstrdup(uc->device);
                }
                uc = uc->next;
        }
        return NULL;
}

int resolve_mount_spec(char **fsname)
{
        char *tmp = *fsname;

        if (is_prefixed_with(*fsname, "UUID="))
                tmp = get_devname_from_uuid(*fsname + 5);
        else if (is_prefixed_with(*fsname, "LABEL="))
                tmp = get_devname_from_label(*fsname + 6);

        if (tmp == *fsname)
                return 0; /* no UUID= or LABEL= prefix found */

        if (tmp)
                *fsname = tmp;
        return 1;
}