freebsd-skq/lib/libc/stdlib/hcreate.c
pfg f94ef3a29c Fix hdestroy() compliance issue.
The hcreate(3) implementation and related functions we inherited
from NetBSD used to free() the key value, something that is not
supported by the standard implementation.

This would cause a segmentation fault when attempting to run
the examples from the opengroup and linux manpages.  NetBSD
has added non-standard calls to provide the previous
behaviour but hdestroy is not very commonly used so at this
time it seems excessive to bring those to FreeBSD.

Bump the __FreeBSD_version as this is an ABI change.

Reference:
http://bugs.dragonflybsd.org/issues/1398

MFC after:	2 weeks
2014-07-21 15:44:59 +00:00

219 lines
5.1 KiB
C

/* $NetBSD: hcreate.c,v 1.7 2011/09/14 23:33:51 christos Exp $ */
/*
* Copyright (c) 2001 Christopher G. Demetriou
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
*/
/*
* hcreate() / hsearch() / hdestroy()
*
* SysV/XPG4 hash table functions.
*
* Implementation done based on NetBSD manual page and Solaris manual page,
* plus my own personal experience about how they're supposed to work.
*
* I tried to look at Knuth (as cited by the Solaris manual page), but
* nobody had a copy in the office, so...
*/
#include <sys/cdefs.h>
#if 0
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: hcreate.c,v 1.8 2011/09/17 16:54:39 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#endif
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/queue.h>
#include <errno.h>
#include <search.h>
#include <stdlib.h>
#include <string.h>
/*
* DO NOT MAKE THIS STRUCTURE LARGER THAN 32 BYTES (4 ptrs on 64-bit
* ptr machine) without adjusting MAX_BUCKETS_LG2 below.
*/
struct internal_entry {
SLIST_ENTRY(internal_entry) link;
ENTRY ent;
};
SLIST_HEAD(internal_head, internal_entry);
#define MIN_BUCKETS_LG2 4
#define MIN_BUCKETS (1 << MIN_BUCKETS_LG2)
/*
* max * sizeof internal_entry must fit into size_t.
* assumes internal_entry is <= 32 (2^5) bytes.
*/
#define MAX_BUCKETS_LG2 (sizeof (size_t) * 8 - 1 - 5)
#define MAX_BUCKETS ((size_t)1 << MAX_BUCKETS_LG2)
/* Default hash function, from db/hash/hash_func.c */
extern u_int32_t (*__default_hash)(const void *, size_t);
static struct hsearch_data htable;
int
hcreate(size_t nel)
{
/* Make sure this is not called when a table already exists. */
if (htable.table != NULL) {
errno = EINVAL;
return 0;
}
return hcreate_r(nel, &htable);
}
int
hcreate_r(size_t nel, struct hsearch_data *head)
{
struct internal_head *table;
size_t idx;
unsigned int p2;
void *p;
/* If nel is too small, make it min sized. */
if (nel < MIN_BUCKETS)
nel = MIN_BUCKETS;
/* If it is too large, cap it. */
if (nel > MAX_BUCKETS)
nel = MAX_BUCKETS;
/* If it is not a power of two in size, round up. */
if ((nel & (nel - 1)) != 0) {
for (p2 = 0; nel != 0; p2++)
nel >>= 1;
nel = 1 << p2;
}
/* Allocate the table. */
head->size = nel;
head->filled = 0;
p = malloc(nel * sizeof table[0]);
if (p == NULL) {
errno = ENOMEM;
return 0;
}
head->table = p;
table = p;
/* Initialize it. */
for (idx = 0; idx < nel; idx++)
SLIST_INIT(&table[idx]);
return 1;
}
void
hdestroy(void)
{
hdestroy_r(&htable);
}
void
hdestroy_r(struct hsearch_data *head)
{
struct internal_entry *ie;
size_t idx;
void *p;
struct internal_head *table;
if (head == NULL)
return;
p = head->table;
head->table = NULL;
table = p;
for (idx = 0; idx < head->size; idx++) {
while (!SLIST_EMPTY(&table[idx])) {
ie = SLIST_FIRST(&table[idx]);
SLIST_REMOVE_HEAD(&table[idx], link);
free(ie);
}
}
free(table);
}
ENTRY *
hsearch(ENTRY item, ACTION action)
{
ENTRY *ep;
(void)hsearch_r(item, action, &ep, &htable);
return ep;
}
int
hsearch_r(ENTRY item, ACTION action, ENTRY **itemp, struct hsearch_data *head)
{
struct internal_head *table, *chain;
struct internal_entry *ie;
uint32_t hashval;
size_t len;
void *p;
p = head->table;
table = p;
len = strlen(item.key);
hashval = (*__default_hash)(item.key, len);
chain = &table[hashval & (head->size - 1)];
ie = SLIST_FIRST(chain);
while (ie != NULL) {
if (strcmp(ie->ent.key, item.key) == 0)
break;
ie = SLIST_NEXT(ie, link);
}
if (ie != NULL) {
*itemp = &ie->ent;
return 1;
} else if (action == FIND) {
*itemp = NULL;
errno = ESRCH;
return 1;
}
ie = malloc(sizeof *ie);
if (ie == NULL)
return 0;
ie->ent.key = item.key;
ie->ent.data = item.data;
SLIST_INSERT_HEAD(chain, ie, link);
*itemp = &ie->ent;
head->filled++;
return 1;
}