busybox/e2fsprogs/blkid/tag.c
2006-03-01 16:39:45 +00:00

333 lines
7.5 KiB
C

/*
* 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;
}
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)"));
DEB_DUMP_TAG(DEBUG_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;
};
extern 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;
}
extern 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;
}