busybox/e2fsprogs/blkid/dev.c

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/*
* dev.c - allocation/initialization/free routines for dev
*
* 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 "blkidP.h"
blkid_dev blkid_new_dev(void)
{
blkid_dev dev;
if (!(dev = (blkid_dev) calloc(1, sizeof(struct blkid_struct_dev))))
return NULL;
INIT_LIST_HEAD(&dev->bid_devs);
INIT_LIST_HEAD(&dev->bid_tags);
return dev;
}
void blkid_free_dev(blkid_dev dev)
{
if (!dev)
return;
DBG(DEBUG_DEV,
printf(" freeing dev %s (%s)\n", dev->bid_name, dev->bid_type));
DEB_DUMP_DEV(DEBUG_DEV, dev);
list_del(&dev->bid_devs);
while (!list_empty(&dev->bid_tags)) {
blkid_tag tag = list_entry(dev->bid_tags.next,
struct blkid_struct_tag,
bit_tags);
blkid_free_tag(tag);
}
if (dev->bid_name)
free(dev->bid_name);
free(dev);
}
/*
* Given a blkid device, return its name
*/
extern const char *blkid_dev_devname(blkid_dev dev)
{
return dev->bid_name;
}
/*
* dev 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 devices in a blkid cache
*/
#define DEV_ITERATE_MAGIC 0x01a5284c
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struct blkid_struct_dev_iterate {
int magic;
blkid_cache cache;
struct list_head *p;
};
extern blkid_dev_iterate blkid_dev_iterate_begin(blkid_cache cache)
{
blkid_dev_iterate iter;
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iter = xmalloc(sizeof(struct blkid_struct_dev_iterate));
iter->magic = DEV_ITERATE_MAGIC;
iter->cache = cache;
iter->p = cache->bic_devs.next;
return (iter);
}
/*
* Return 0 on success, -1 on error
*/
extern int blkid_dev_next(blkid_dev_iterate iter,
blkid_dev *dev)
{
*dev = 0;
if (!iter || iter->magic != DEV_ITERATE_MAGIC ||
iter->p == &iter->cache->bic_devs)
return -1;
*dev = list_entry(iter->p, struct blkid_struct_dev, bid_devs);
iter->p = iter->p->next;
return 0;
}
extern void blkid_dev_iterate_end(blkid_dev_iterate iter)
{
if (!iter || iter->magic != DEV_ITERATE_MAGIC)
return;
iter->magic = 0;
free(iter);
}