e2fsprogs/blkid/dev.c

   1 /*
   2  * dev.c - allocation/initialization/free routines for dev
   3  *
   4  * Copyright (C) 2001 Andreas Dilger
   5  * Copyright (C) 2003 Theodore Ts'o
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the
   9  * GNU Lesser General Public License.
  10  * %End-Header%
  11  */
  12
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 #include "blkidP.h"
  17
  18 blkid_dev blkid_new_dev(void)
  19 {
  20         blkid_dev dev;
  21
  22         if (!(dev = (blkid_dev) calloc(1, sizeof(struct blkid_struct_dev))))
  23                 return NULL;
  24
  25         INIT_LIST_HEAD(&dev->bid_devs);
  26         INIT_LIST_HEAD(&dev->bid_tags);
  27
  28         return dev;
  29 }
  30
  31 void blkid_free_dev(blkid_dev dev)
  32 {
  33         if (!dev)
  34                 return;
  35
  36         DBG(DEBUG_DEV,
  37             printf("  freeing dev %s (%s)\n", dev->bid_name, dev->bid_type));
  38         DEB_DUMP_DEV(DEBUG_DEV, dev);
  39
  40         list_del(&dev->bid_devs);
  41         while (!list_empty(&dev->bid_tags)) {
  42                 blkid_tag tag = list_entry(dev->bid_tags.next,
  43                                            struct blkid_struct_tag,
  44                                            bit_tags);
  45                 blkid_free_tag(tag);
  46         }
  47         if (dev->bid_name)
  48                 free(dev->bid_name);
  49         free(dev);
  50 }
  51
  52 /*
  53  * Given a blkid device, return its name
  54  */
  55 extern const char *blkid_dev_devname(blkid_dev dev)
  56 {
  57         return dev->bid_name;
  58 }
  59
  60 /*
  61  * dev iteration routines for the public libblkid interface.
  62  *
  63  * These routines do not expose the list.h implementation, which are a
  64  * contamination of the namespace, and which force us to reveal far, far
  65  * too much of our internal implemenation.  I'm not convinced I want
  66  * to keep list.h in the long term, anyway.  It's fine for kernel
  67  * programming, but performance is not the #1 priority for this
  68  * library, and I really don't like the tradeoff of type-safety for
  69  * performance for this application.  [tytso:20030125.2007EST]
  70  */
  71
  72 /*
  73  * This series of functions iterate over all devices in a blkid cache
  74  */
  75 #define DEV_ITERATE_MAGIC       0x01a5284c
  76
  77 struct blkid_struct_dev_iterate {
  78         int                     magic;
  79         blkid_cache             cache;
  80         struct list_head        *p;
  81 };
  82
  83 extern blkid_dev_iterate blkid_dev_iterate_begin(blkid_cache cache)
  84 {
  85         blkid_dev_iterate       iter;
  86
  87         iter = xmalloc(sizeof(struct blkid_struct_dev_iterate));
  88         iter->magic = DEV_ITERATE_MAGIC;
  89         iter->cache = cache;
  90         iter->p = cache->bic_devs.next;
  91         return (iter);
  92 }
  93
  94 /*
  95  * Return 0 on success, -1 on error
  96  */
  97 extern int blkid_dev_next(blkid_dev_iterate iter,
  98                           blkid_dev *dev)
  99 {
 100         *dev = 0;
 101         if (!iter || iter->magic != DEV_ITERATE_MAGIC ||
 102             iter->p == &iter->cache->bic_devs)
 103                 return -1;
 104         *dev = list_entry(iter->p, struct blkid_struct_dev, bid_devs);
 105         iter->p = iter->p->next;
 106         return 0;
 107 }
 108
 109 extern void blkid_dev_iterate_end(blkid_dev_iterate iter)
 110 {
 111         if (!iter || iter->magic != DEV_ITERATE_MAGIC)
 112                 return;
 113         iter->magic = 0;
 114         free(iter);
 115 }
 116