source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/blkid/tag.c@ 821

/*
 * tag.c - allocation/initialization/free routines for tag structs
 *
 * Copyright (C) 2001 Andreas Dilger
 * Copyright (C) 2003 Theodore Ts'o
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the
 * GNU Lesser General Public License.
 * %End-Header%
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "blkidP.h"

static blkid_tag blkid_new_tag(void)
{
    blkid_tag tag;

    if (!(tag = (blkid_tag) calloc(1, sizeof(struct blkid_struct_tag))))
        return NULL;

    INIT_LIST_HEAD(&tag->bit_tags);
    INIT_LIST_HEAD(&tag->bit_names);

    return tag;
}

#ifdef CONFIG_BLKID_DEBUG
void blkid_debug_dump_tag(blkid_tag tag)
{
    if (!tag) {
        printf("    tag: NULL\n");
        return;
    }

    printf("    tag: %s=\"%s\"\n", tag->bit_name, tag->bit_val);
}
#endif

void blkid_free_tag(blkid_tag tag)
{
    if (!tag)
        return;

    DBG(DEBUG_TAG, printf("    freeing tag %s=%s\n", tag->bit_name,
           tag->bit_val ? tag->bit_val : "(NULL)"));
    DBG(DEBUG_TAG, blkid_debug_dump_tag(tag));

    list_del(&tag->bit_tags);   /* list of tags for this device */
    list_del(&tag->bit_names);  /* list of tags with this type */

    free(tag->bit_name);
    free(tag->bit_val);
    free(tag);
}

/*
 * Find the desired tag on a device.  If value is NULL, then the
 * first such tag is returned, otherwise return only exact tag if found.
 */
blkid_tag blkid_find_tag_dev(blkid_dev dev, const char *type)
{
    struct list_head *p;

    if (!dev || !type)
        return NULL;

    list_for_each(p, &dev->bid_tags) {
        blkid_tag tmp = list_entry(p, struct blkid_struct_tag,
                       bit_tags);

        if (!strcmp(tmp->bit_name, type))
            return tmp;
    }
    return NULL;
}

/*
 * Find the desired tag type in the cache.
 * We return the head tag for this tag type.
 */
static blkid_tag blkid_find_head_cache(blkid_cache cache, const char *type)
{
    blkid_tag head = NULL, tmp;
    struct list_head *p;

    if (!cache || !type)
        return NULL;

    list_for_each(p, &cache->bic_tags) {
        tmp = list_entry(p, struct blkid_struct_tag, bit_tags);
        if (!strcmp(tmp->bit_name, type)) {
            DBG(DEBUG_TAG,
                printf("    found cache tag head %s\n", type));
            head = tmp;
            break;
        }
    }
    return head;
}

/*
 * Set a tag on an existing device.
 *
 * If value is NULL, then delete the tagsfrom the device.
 */
int blkid_set_tag(blkid_dev dev, const char *name,
          const char *value, const int vlength)
{
    blkid_tag   t = 0, head = 0;
    char        *val = 0;

    if (!dev || !name)
        return -BLKID_ERR_PARAM;

    if (!(val = blkid_strndup(value, vlength)) && value)
        return -BLKID_ERR_MEM;
    t = blkid_find_tag_dev(dev, name);
    if (!value) {
        blkid_free_tag(t);
    } else if (t) {
        if (!strcmp(t->bit_val, val)) {
            /* Same thing, exit */
            free(val);
            return 0;
        }
        free(t->bit_val);
        t->bit_val = val;
    } else {
        /* Existing tag not present, add to device */
        if (!(t = blkid_new_tag()))
            goto errout;
        t->bit_name = blkid_strdup(name);
        t->bit_val = val;
        t->bit_dev = dev;

        list_add_tail(&t->bit_tags, &dev->bid_tags);

        if (dev->bid_cache) {
            head = blkid_find_head_cache(dev->bid_cache,
                             t->bit_name);
            if (!head) {
                head = blkid_new_tag();
                if (!head)
                    goto errout;

                DBG(DEBUG_TAG,
                    printf("    creating new cache tag head %s\n", name));
                head->bit_name = blkid_strdup(name);
                if (!head->bit_name)
                    goto errout;
                list_add_tail(&head->bit_tags,
                          &dev->bid_cache->bic_tags);
            }
            list_add_tail(&t->bit_names, &head->bit_names);
        }
    }

    /* Link common tags directly to the device struct */
    if (!strcmp(name, "TYPE"))
        dev->bid_type = val;
    else if (!strcmp(name, "LABEL"))
        dev->bid_label = val;
    else if (!strcmp(name, "UUID"))
        dev->bid_uuid = val;

    if (dev->bid_cache)
        dev->bid_cache->bic_flags |= BLKID_BIC_FL_CHANGED;
    return 0;

errout:
    blkid_free_tag(t);
    if (!t)
        free(val);
    blkid_free_tag(head);
    return -BLKID_ERR_MEM;
}


/*
 * Parse a "NAME=value" string.  This is slightly different than
 * parse_token, because that will end an unquoted value at a space, while
 * this will assume that an unquoted value is the rest of the token (e.g.
 * if we are passed an already quoted string from the command-line we don't
 * have to both quote and escape quote so that the quotes make it to
 * us).
 *
 * Returns 0 on success, and -1 on failure.
 */
int blkid_parse_tag_string(const char *token, char **ret_type, char **ret_val)
{
    char *name, *value, *cp;

    DBG(DEBUG_TAG, printf("trying to parse '%s' as a tag\n", token));

    if (!token || !(cp = strchr(token, '=')))
        return -1;

    name = blkid_strdup(token);
    if (!name)
        return -1;
    value = name + (cp - token);
    *value++ = '\0';
    if (*value == '"' || *value == '\'') {
        char c = *value++;
        if (!(cp = strrchr(value, c)))
            goto errout; /* missing closing quote */
        *cp = '\0';
    }
    value = blkid_strdup(value);
    if (!value)
        goto errout;

    *ret_type = name;
    *ret_val = value;

    return 0;

errout:
    free(name);
    return -1;
}

/*
 * Tag iteration routines for the public libblkid interface.
 *
 * These routines do not expose the list.h implementation, which are a
 * contamination of the namespace, and which force us to reveal far, far
 * too much of our internal implemenation.  I'm not convinced I want
 * to keep list.h in the long term, anyway.  It's fine for kernel
 * programming, but performance is not the #1 priority for this
 * library, and I really don't like the tradeoff of type-safety for
 * performance for this application.  [tytso:20030125.2007EST]
 */

/*
 * This series of functions iterate over all tags in a device
 */
#define TAG_ITERATE_MAGIC   0x01a5284c

struct blkid_struct_tag_iterate {
    int         magic;
    blkid_dev       dev;
    struct list_head    *p;
};

blkid_tag_iterate blkid_tag_iterate_begin(blkid_dev dev)
{
    blkid_tag_iterate   iter;

    iter = xmalloc(sizeof(struct blkid_struct_tag_iterate));
    iter->magic = TAG_ITERATE_MAGIC;
    iter->dev = dev;
    iter->p = dev->bid_tags.next;
    return (iter);
}

/*
 * Return 0 on success, -1 on error
 */
extern int blkid_tag_next(blkid_tag_iterate iter,
              const char **type, const char **value)
{
    blkid_tag tag;

    *type = 0;
    *value = 0;
    if (!iter || iter->magic != TAG_ITERATE_MAGIC ||
        iter->p == &iter->dev->bid_tags)
        return -1;
    tag = list_entry(iter->p, struct blkid_struct_tag, bit_tags);
    *type = tag->bit_name;
    *value = tag->bit_val;
    iter->p = iter->p->next;
    return 0;
}

void blkid_tag_iterate_end(blkid_tag_iterate iter)
{
    if (!iter || iter->magic != TAG_ITERATE_MAGIC)
        return;
    iter->magic = 0;
    free(iter);
}

/*
 * This function returns a device which matches a particular
 * type/value pair.  If there is more than one device that matches the
 * search specification, it returns the one with the highest priority
 * value.  This allows us to give preference to EVMS or LVM devices.
 *
 * XXX there should also be an interface which uses an iterator so we
 * can get all of the devices which match a type/value search parameter.
 */
extern blkid_dev blkid_find_dev_with_tag(blkid_cache cache,
                     const char *type,
                     const char *value)
{
    blkid_tag   head;
    blkid_dev   dev;
    int     pri;
    struct list_head *p;

    if (!cache || !type || !value)
        return NULL;

    blkid_read_cache(cache);

    DBG(DEBUG_TAG, printf("looking for %s=%s in cache\n", type, value));

try_again:
    pri = -1;
    dev = 0;
    head = blkid_find_head_cache(cache, type);

    if (head) {
        list_for_each(p, &head->bit_names) {
            blkid_tag tmp = list_entry(p, struct blkid_struct_tag,
                           bit_names);

            if (!strcmp(tmp->bit_val, value) &&
                tmp->bit_dev->bid_pri > pri) {
                dev = tmp->bit_dev;
                pri = dev->bid_pri;
            }
        }
    }
    if (dev && !(dev->bid_flags & BLKID_BID_FL_VERIFIED)) {
        dev = blkid_verify(cache, dev);
        if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))
            goto try_again;
    }

    if (!dev && !(cache->bic_flags & BLKID_BIC_FL_PROBED)) {
        if (blkid_probe_all(cache) < 0)
            return NULL;
        goto try_again;
    }
    return dev;
}

#ifdef TEST_PROGRAM
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
extern char *optarg;
extern int optind;
#endif

void usage(char *prog)
{
    fprintf(stderr, "Usage: %s [-f blkid_file] [-m debug_mask] device "
        "[type value]\n", 
        prog);
    fprintf(stderr, "\tList all tags for a device and exit\n", prog);
    exit(1);
}

int main(int argc, char **argv)
{
    blkid_tag_iterate   iter;
    blkid_cache         cache = NULL;
    blkid_dev       dev;
    int         c, ret, found;
    int         flags = BLKID_DEV_FIND;
    char            *tmp;
    char            *file = NULL;
    char            *devname = NULL;
    char            *search_type = NULL;
    char            *search_value = NULL;
    const char      *type, *value;

    while ((c = getopt (argc, argv, "m:f:")) != EOF)
        switch (c) {
        case 'f':
            file = optarg;
            break;
        case 'm':
            blkid_debug_mask = strtoul (optarg, &tmp, 0);
            if (*tmp) {
                fprintf(stderr, "Invalid debug mask: %d\n", 
                    optarg);
                exit(1);
            }
            break;
        case '?':
            usage(argv[0]);
        }
    if (argc > optind)
        devname = argv[optind++];
    if (argc > optind)
        search_type = argv[optind++];
    if (argc > optind)
        search_value = argv[optind++];
    if (!devname || (argc != optind))
        usage(argv[0]);

    if ((ret = blkid_get_cache(&cache, file)) != 0) {
        fprintf(stderr, "%s: error creating cache (%d)\n",
            argv[0], ret);
        exit(1);
    }

    dev = blkid_get_dev(cache, devname, flags);
    if (!dev) {
        fprintf(stderr, "%s: Can not find device in blkid cache\n");
        exit(1);
    }
    if (search_type) {
        found = blkid_dev_has_tag(dev, search_type, search_value);
        printf("Device %s: (%s, %s) %s\n", blkid_dev_devname(dev),
               search_type, search_value ? search_value : "NULL", 
               found ? "FOUND" : "NOT FOUND");
        return(!found);
    }
    printf("Device %s...\n", blkid_dev_devname(dev));

    iter = blkid_tag_iterate_begin(dev);
    while (blkid_tag_next(iter, &type, &value) == 0) {
        printf("\tTag %s has value %s\n", type, value);
    }
    blkid_tag_iterate_end(iter);

    blkid_put_cache(cache);
    return (0);
}
#endif