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samba-mirror/source/lib/talloc.c
0001-01-01 00:00:00 +00:00

471 lines
9.4 KiB
C

/*
Samba Unix SMB/CIFS implementation.
Samba temporary memory allocation functions
Copyright (C) Andrew Tridgell 2000
Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/**
@defgroup talloc Simple memory allocator
@{
This is a very simple temporary memory allocator. To use it do the following:
1) when you first want to allocate a pool of meomry use
talloc_init() and save the resulting context pointer somewhere
2) to allocate memory use talloc()
3) when _all_ of the memory allocated using this context is no longer needed
use talloc_destroy()
talloc does not zero the memory. It guarantees memory of a
TALLOC_ALIGN alignment
@sa talloc.h
*/
/**
* @todo We could allocate both the talloc_chunk structure, and the
* memory it contains all in one allocation, which might be a bit
* faster and perhaps use less memory overhead.
*
* That smells like a premature optimization, though. -- mbp
**/
/**
* If you want testing for memory corruption, link with dmalloc or use
* Insure++. It doesn't seem useful to duplicate them here.
**/
#include "includes.h"
struct talloc_chunk {
struct talloc_chunk *next;
size_t size;
void *ptr;
};
struct talloc_ctx {
struct talloc_chunk *list;
size_t total_alloc_size;
/** The name recorded for this pool, if any. Should describe
* the purpose for which it was allocated. The string is
* allocated within the pool. **/
char *name;
/** Pointer to the next allocate talloc pool, so that we can
* summarize all talloc memory usage. **/
struct talloc_ctx *next_ctx;
};
/**
* Start of linked list of all talloc pools.
*
* @todo We should turn the global list off when using Insure++,
* otherwise all the memory will be seen as still reachable.
**/
static TALLOC_CTX *list_head = NULL;
/**
* Add to the global list
**/
static void talloc_enroll(TALLOC_CTX *t)
{
t->next_ctx = list_head;
list_head = t;
}
static void talloc_disenroll(TALLOC_CTX *t)
{
TALLOC_CTX **ttmp;
/* Use a double-* so that no special case is required for the
* list head. */
for (ttmp = &list_head; *ttmp; ttmp = &((*ttmp)->next_ctx))
if (*ttmp == t) {
/* ttmp is the link that points to t, either
* list_head or the next_ctx link in its
* predecessor */
*ttmp = t->next_ctx;
t->next_ctx = NULL; /* clobber */
return;
}
abort(); /* oops, this talloc was already
* clobbered or something else went
* wrong. */
}
/** Create a new talloc context. **/
static TALLOC_CTX *talloc_init_internal(void)
{
TALLOC_CTX *t;
t = (TALLOC_CTX *)malloc(sizeof(TALLOC_CTX));
if (t) {
t->list = NULL;
t->total_alloc_size = 0;
t->name = NULL;
talloc_enroll(t);
}
return t;
}
/**
* Create a new talloc context, with a name specifying its purpose.
**/
TALLOC_CTX *talloc_init(char const *fmt, ...)
{
TALLOC_CTX *t;
va_list ap;
t = talloc_init_internal();
if (t && fmt) {
/*
* t->name must not be talloced.
* as destroying the pool would destroy it. JRA.
*/
t->name = NULL;
va_start(ap, fmt);
vasprintf(&t->name, fmt, ap);
va_end(ap);
if (!t->name) {
talloc_destroy(t);
t = NULL;
}
}
return t;
}
/** Allocate a bit of memory from the specified pool **/
void *talloc(TALLOC_CTX *t, size_t size)
{
void *p;
struct talloc_chunk *tc;
if (!t || size == 0) return NULL;
p = malloc(size);
if (p) {
tc = malloc(sizeof(*tc));
if (tc) {
tc->ptr = p;
tc->size = size;
tc->next = t->list;
t->list = tc;
t->total_alloc_size += size;
}
else {
SAFE_FREE(p);
}
}
return p;
}
/** A talloc version of realloc */
void *talloc_realloc(TALLOC_CTX *t, void *ptr, size_t size)
{
struct talloc_chunk *tc;
void *new_ptr;
/* size zero is equivalent to free() */
if (!t || size == 0)
return NULL;
/* realloc(NULL) is equavalent to malloc() */
if (ptr == NULL)
return talloc(t, size);
for (tc=t->list; tc; tc=tc->next) {
if (tc->ptr == ptr) {
new_ptr = Realloc(ptr, size);
if (new_ptr) {
t->total_alloc_size += (size - tc->size);
tc->size = size;
tc->ptr = new_ptr;
}
return new_ptr;
}
}
return NULL;
}
/** Destroy all the memory allocated inside @p t, but not @p t
* itself. */
void talloc_destroy_pool(TALLOC_CTX *t)
{
struct talloc_chunk *c;
if (!t)
return;
while (t->list) {
c = t->list->next;
SAFE_FREE(t->list->ptr);
SAFE_FREE(t->list);
t->list = c;
}
t->total_alloc_size = 0;
}
/** Destroy a whole pool including the context */
void talloc_destroy(TALLOC_CTX *t)
{
if (!t)
return;
talloc_destroy_pool(t);
talloc_disenroll(t);
SAFE_FREE(t->name);
memset(t, 0, sizeof(TALLOC_CTX));
SAFE_FREE(t);
}
/** Return the current total size of the pool. */
size_t talloc_pool_size(TALLOC_CTX *t)
{
if (t)
return t->total_alloc_size;
else
return 0;
}
const char * talloc_pool_name(TALLOC_CTX const *t)
{
if (t)
return t->name;
else
return NULL;
}
/** talloc and zero memory. */
void *talloc_zero(TALLOC_CTX *t, size_t size)
{
void *p = talloc(t, size);
if (p)
memset(p, '\0', size);
return p;
}
/** memdup with a talloc. */
void *talloc_memdup(TALLOC_CTX *t, const void *p, size_t size)
{
void *newp = talloc(t,size);
if (newp)
memcpy(newp, p, size);
return newp;
}
/** strdup with a talloc */
char *talloc_strdup(TALLOC_CTX *t, const char *p)
{
if (p)
return talloc_memdup(t, p, strlen(p) + 1);
else
return NULL;
}
/** strdup_w with a talloc */
smb_ucs2_t *talloc_strdup_w(TALLOC_CTX *t, const smb_ucs2_t *p)
{
if (p)
return talloc_memdup(t, p, (strlen_w(p) + 1) * sizeof(smb_ucs2_t));
else
return NULL;
}
/**
* Perform string formatting, and return a pointer to newly allocated
* memory holding the result, inside a memory pool.
**/
char *talloc_asprintf(TALLOC_CTX *t, const char *fmt, ...)
{
va_list ap;
char *ret;
va_start(ap, fmt);
ret = talloc_vasprintf(t, fmt, ap);
va_end(ap);
return ret;
}
char *talloc_vasprintf(TALLOC_CTX *t, const char *fmt, va_list ap)
{
int len;
char *ret;
va_list ap2;
VA_COPY(ap2, ap);
len = vsnprintf(NULL, 0, fmt, ap2);
ret = talloc(t, len+1);
if (ret) {
VA_COPY(ap2, ap);
vsnprintf(ret, len+1, fmt, ap2);
}
return ret;
}
/**
* Realloc @p s to append the formatted result of @p fmt and return @p
* s, which may have moved. Good for gradually accumulating output
* into a string buffer.
**/
char *talloc_asprintf_append(TALLOC_CTX *t, char *s,
const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
s = talloc_vasprintf_append(t, s, fmt, ap);
va_end(ap);
return s;
}
/**
* Realloc @p s to append the formatted result of @p fmt and @p ap,
* and return @p s, which may have moved. Good for gradually
* accumulating output into a string buffer.
**/
char *talloc_vasprintf_append(TALLOC_CTX *t, char *s,
const char *fmt, va_list ap)
{
int len, s_len;
va_list ap2;
VA_COPY(ap2, ap);
s_len = strlen(s);
len = vsnprintf(NULL, 0, fmt, ap2);
s = talloc_realloc(t, s, s_len + len+1);
if (!s) return NULL;
VA_COPY(ap2, ap);
vsnprintf(s+s_len, len+1, fmt, ap2);
return s;
}
/**
* Return a human-readable description of all talloc memory usage.
* The result is allocated from @p t.
**/
char *talloc_describe_all(TALLOC_CTX *rt)
{
int n_pools = 0, total_chunks = 0;
size_t total_bytes = 0;
TALLOC_CTX *it;
char *s;
if (!rt) return NULL;
s = talloc_asprintf(rt, "global talloc allocations in pid: %u\n",
(unsigned) sys_getpid());
s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
"name", "chunks", "bytes");
s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
"----------------------------------------",
"--------",
"--------");
for (it = list_head; it; it = it->next_ctx) {
size_t bytes;
int n_chunks;
fstring what;
n_pools++;
talloc_get_allocation(it, &bytes, &n_chunks);
if (it->name)
fstrcpy(what, it->name);
else
slprintf(what, sizeof(what), "@%p", it);
s = talloc_asprintf_append(rt, s, "%-40s %8u %8u\n",
what,
(unsigned) n_chunks,
(unsigned) bytes);
total_bytes += bytes;
total_chunks += n_chunks;
}
s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
"----------------------------------------",
"--------",
"--------");
s = talloc_asprintf_append(rt, s, "%-40s %8u %8u\n",
"TOTAL",
(unsigned) total_chunks, (unsigned) total_bytes);
return s;
}
/**
* Return an estimated memory usage for the specified pool. This does
* not include memory used by the underlying malloc implementation.
**/
void talloc_get_allocation(TALLOC_CTX *t,
size_t *total_bytes,
int *n_chunks)
{
struct talloc_chunk *chunk;
if (t) {
*total_bytes = 0;
*n_chunks = 0;
for (chunk = t->list; chunk; chunk = chunk->next) {
n_chunks[0]++;
*total_bytes += chunk->size;
}
}
}
/** @} */