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/*-
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* There's no malloc interface, WiredTiger never calls malloc.
*
* The problem is an application might allocate memory, write secret stuff in
* it, free the memory, then WiredTiger allocates the memory and uses it for a
* file page or log record, then writes it to disk, without having overwritten
* it fully. That results in the secret stuff being protected by WiredTiger's
* permission mechanisms, potentially inappropriate for the secret stuff.
*/
/*
* __wt_calloc --
* ANSI calloc function.
*/
int
__wt_calloc(WT_SESSION_IMPL *session, size_t number, size_t size, void *retp)
{
void *p;
/*
* !!!
* This function MUST handle a NULL WT_SESSION_IMPL handle.
*/
WT_ASSERT(session, number != 0 && size != 0);
if (session != NULL)
WT_STAT_FAST_CONN_INCR(session, memory_allocation);
if ((p = calloc(number, size)) == NULL)
WT_RET_MSG(session, __wt_errno(), "memory allocation");
*(void **)retp = p;
return (0);
}
/*
* __wt_realloc --
* ANSI realloc function.
*/
int
__wt_realloc(WT_SESSION_IMPL *session,
size_t *bytes_allocated_ret, size_t bytes_to_allocate, void *retp)
{
void *p;
size_t bytes_allocated;
/*
* !!!
* This function MUST handle a NULL WT_SESSION_IMPL handle.
*
* Sometimes we're allocating memory and we don't care about the
* final length -- bytes_allocated_ret may be NULL.
*/
p = *(void **)retp;
bytes_allocated =
(bytes_allocated_ret == NULL) ? 0 : *bytes_allocated_ret;
WT_ASSERT(session,
(p == NULL && bytes_allocated == 0) ||
(p != NULL &&
(bytes_allocated_ret == NULL || bytes_allocated != 0)));
WT_ASSERT(session, bytes_to_allocate != 0);
WT_ASSERT(session, bytes_allocated < bytes_to_allocate);
if (session != NULL) {
if (p == NULL)
WT_STAT_FAST_CONN_INCR(session, memory_allocation);
else
WT_STAT_FAST_CONN_INCR(session, memory_grow);
}
if ((p = realloc(p, bytes_to_allocate)) == NULL)
WT_RET_MSG(session, __wt_errno(), "memory allocation");
/*
* Clear the allocated memory -- an application might: allocate memory,
* write secret stuff into it, free the memory, then we re-allocate the
* memory and use it for a file page or log record, and then write it to
* disk. That would result in the secret stuff being protected by the
* WiredTiger permission mechanisms, potentially inappropriate for the
* secret stuff.
*/
memset((uint8_t *)
p + bytes_allocated, 0, bytes_to_allocate - bytes_allocated);
/* Update caller's bytes allocated value. */
if (bytes_allocated_ret != NULL)
*bytes_allocated_ret = bytes_to_allocate;
*(void **)retp = p;
return (0);
}
/*
* __wt_realloc_aligned --
* ANSI realloc function that aligns to buffer boundaries, configured with
* the "buffer_alignment" key to wiredtiger_open.
*/
int
__wt_realloc_aligned(WT_SESSION_IMPL *session,
size_t *bytes_allocated_ret, size_t bytes_to_allocate, void *retp)
{
WT_DECL_RET;
/*
* !!!
* This function MUST handle a NULL WT_SESSION_IMPL handle.
*/
if (session != NULL && S2C(session)->buffer_alignment > 0) {
void *p, *newp;
size_t bytes_allocated;
/*
* Sometimes we're allocating memory and we don't care about the
* final length -- bytes_allocated_ret may be NULL.
*/
p = *(void **)retp;
bytes_allocated =
(bytes_allocated_ret == NULL) ? 0 : *bytes_allocated_ret;
WT_ASSERT(session,
(p == NULL && bytes_allocated == 0) ||
(p != NULL &&
(bytes_allocated_ret == NULL || bytes_allocated != 0)));
WT_ASSERT(session, bytes_to_allocate != 0);
WT_ASSERT(session, bytes_allocated < bytes_to_allocate);
if (session != NULL)
WT_STAT_FAST_CONN_INCR(session, memory_allocation);
if ((newp = _aligned_malloc(
S2C(session)->buffer_alignment,
bytes_to_allocate)) != 0)
WT_RET_MSG(session, errno, "memory allocation");
if (p != NULL)
memcpy(newp, p, bytes_allocated);
__wt_free(session, p);
p = newp;
/* Clear the allocated memory (see above). */
memset((uint8_t *)p + bytes_allocated, 0,
bytes_to_allocate - bytes_allocated);
/* Update caller's bytes allocated value. */
if (bytes_allocated_ret != NULL)
*bytes_allocated_ret = bytes_to_allocate;
*(void **)retp = p;
return (0);
}
/*
* If there is no posix_memalign function, or no alignment configured,
* fall back to realloc.
*/
return (__wt_realloc(
session, bytes_allocated_ret, bytes_to_allocate, retp));
}
/*
* __wt_strndup --
* Duplicate a byte string of a given length (and NUL-terminate).
*/
int
__wt_strndup(WT_SESSION_IMPL *session, const void *str, size_t len, void *retp)
{
void *p;
if (str == NULL) {
*(void **)retp = NULL;
return (0);
}
WT_RET(__wt_calloc(session, len + 1, 1, &p));
/*
* Don't change this to strncpy, we rely on this function to duplicate
* "strings" that contain nul bytes.
*/
memcpy(p, str, len);
*(void **)retp = p;
return (0);
}
/*
* __wt_strdup --
* ANSI strdup function.
*/
int
__wt_strdup(WT_SESSION_IMPL *session, const char *str, void *retp)
{
return (__wt_strndup(
session, str, (str == NULL) ? 0 : strlen(str), retp));
}
/*
* __wt_free_int --
* ANSI free function.
*/
void
__wt_free_int(WT_SESSION_IMPL *session, const void *p_arg)
{
void *p;
p = *(void **)p_arg;
if (p == NULL) /* ANSI C free semantics */
return;
/*
* If there's a serialization bug we might race with another thread.
* We can't avoid the race (and we aren't willing to flush memory),
* but we minimize the window by clearing the free address, hoping a
* racing thread will see, and won't free, a NULL pointer.
*/
*(void **)p_arg = NULL;
/*
* !!!
* This function MUST handle a NULL WT_SESSION_IMPL handle.
*/
if (session != NULL)
WT_STAT_FAST_CONN_INCR(session, memory_free);
free(p);
}
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