/* Copyright 2000-2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef APR_POOLS_H
#define APR_POOLS_H
/**
* @file apr_pools.h
* @brief APR memory allocation
*
* Resource allocation routines...
*
* designed so that we don't have to keep track of EVERYTHING so that
* it can be explicitly freed later (a fundamentally unsound strategy ---
* particularly in the presence of die()).
*
* Instead, we maintain pools, and allocate items (both memory and I/O
* handlers) from the pools --- currently there are two, one for per
* transaction info, and one for config info. When a transaction is over,
* we can delete everything in the per-transaction apr_pool_t without fear,
* and without thinking too hard about it either.
*/
#include "apr.h"
#include "apr_errno.h"
#include "apr_general.h" /* for APR_STRINGIFY */
#define APR_WANT_MEMFUNC /**< for no good reason? */
#include "apr_want.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup apr_pools Memory Pool Functions
* @ingroup APR
* @{
*/
/** The fundamental pool type */
typedef struct apr_pool_t apr_pool_t;
/**
* Declaration helper macro to construct apr_foo_pool_get()s.
*
* This standardized macro is used by opaque (APR) data types to return
* the apr_pool_t that is associated with the data type.
*
* APR_POOL_DECLARE_ACCESSOR() is used in a header file to declare the
* accessor function. A typical usage and result would be:
*
* APR_POOL_DECLARE_ACCESSOR(file);
* becomes:
* APR_DECLARE(apr_pool_t *) apr_file_pool_get(apr_file_t *ob);
*
* @remark Doxygen unwraps this macro (via doxygen.conf) to provide
* actual help for each specific occurance of apr_foo_pool_get.
* @remark the linkage is specified for APR. It would be possible to expand
* the macros to support other linkages.
*/
#define APR_POOL_DECLARE_ACCESSOR(type) \
APR_DECLARE(apr_pool_t *) apr_##type##_pool_get \
(const apr_##type##_t *the##type)
/**
* Implementation helper macro to provide apr_foo_pool_get()s.
*
* In the implementation, the APR_POOL_IMPLEMENT_ACCESSOR() is used to
* actually define the function. It assumes the field is named "pool".
*/
#define APR_POOL_IMPLEMENT_ACCESSOR(type) \
APR_DECLARE(apr_pool_t *) apr_##type##_pool_get \
(const apr_##type##_t *the##type) \
{ return the##type->pool; }
/**
* Pool debug levels
*
*
* | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
* ---------------------------------
* | | | | | | | | x | General debug code enabled (usefull in
* combination with --with-efence).
*
* | | | | | | | x | | Verbose output on stderr (report
* CREATE, CLEAR, DESTROY).
*
* | | | | x | | | | | Verbose output on stderr (report
* PALLOC, PCALLOC).
*
* | | | | | | x | | | Lifetime checking. On each use of a
* pool, check its lifetime. If the pool
* is out of scope, abort().
* In combination with the verbose flag
* above, it will output LIFE in such an
* event prior to aborting.
*
* | | | | | x | | | | Pool owner checking. On each use of a
* pool, check if the current thread is the
* pools owner. If not, abort(). In
* combination with the verbose flag above,
* it will output OWNER in such an event
* prior to aborting. Use the debug
* function apr_pool_owner_set() to switch
* a pools ownership.
*
* When no debug level was specified, assume general debug mode.
* If level 0 was specified, debugging is switched off
*
*/
#if defined(APR_POOL_DEBUG)
#if (APR_POOL_DEBUG != 0) && (APR_POOL_DEBUG - 0 == 0)
#undef APR_POOL_DEBUG
#define APR_POOL_DEBUG 1
#endif
#else
#define APR_POOL_DEBUG 0
#endif
/** the place in the code where the particular function was called */
#define APR_POOL__FILE_LINE__ __FILE__ ":" APR_STRINGIFY(__LINE__)
/** A function that is called when allocation fails. */
typedef int (*apr_abortfunc_t)(int retcode);
/*
* APR memory structure manipulators (pools, tables, and arrays).
*/
/*
* Initialization
*/
/**
* Setup all of the internal structures required to use pools
* @remark Programs do NOT need to call this directly. APR will call this
* automatically from apr_initialize.
* @internal
*/
APR_DECLARE(apr_status_t) apr_pool_initialize(void);
/**
* Tear down all of the internal structures required to use pools
* @remark Programs do NOT need to call this directly. APR will call this
* automatically from apr_terminate.
* @internal
*/
APR_DECLARE(void) apr_pool_terminate(void);
/*
* Pool creation/destruction
*/
#include "apr_allocator.h"
/**
* Create a new pool.
* @param newpool The pool we have just created.
* @param parent The parent pool. If this is NULL, the new pool is a root
* pool. If it is non-NULL, the new pool will inherit all
* of its parent pool's attributes, except the apr_pool_t will
* be a sub-pool.
* @param abort_fn A function to use if the pool cannot allocate more memory.
* @param allocator The allocator to use with the new pool. If NULL the
* allocator of the parent pool will be used.
*/
APR_DECLARE(apr_status_t) apr_pool_create_ex(apr_pool_t **newpool,
apr_pool_t *parent,
apr_abortfunc_t abort_fn,
apr_allocator_t *allocator);
/**
* Debug version of apr_pool_create_ex.
* @param newpool @see apr_pool_create.
* @param parent @see apr_pool_create.
* @param abort_fn @see apr_pool_create.
* @param allocator @see apr_pool_create.
* @param file_line Where the function is called from.
* This is usually APR_POOL__FILE_LINE__.
* @remark Only available when APR_POOL_DEBUG is defined.
* Call this directly if you have you apr_pool_create_ex
* calls in a wrapper function and wish to override
* the file_line argument to reflect the caller of
* your wrapper function. If you do not have
* apr_pool_create_ex in a wrapper, trust the macro
* and don't call apr_pool_create_ex_debug directly.
*/
APR_DECLARE(apr_status_t) apr_pool_create_ex_debug(apr_pool_t **newpool,
apr_pool_t *parent,
apr_abortfunc_t abort_fn,
apr_allocator_t *allocator,
const char *file_line);
#if APR_POOL_DEBUG
#define apr_pool_create_ex(newpool, parent, abort_fn, allocator) \
apr_pool_create_ex_debug(newpool, parent, abort_fn, allocator, \
APR_POOL__FILE_LINE__)
#endif
/**
* Create a new pool.
* @param newpool The pool we have just created.
* @param parent The parent pool. If this is NULL, the new pool is a root
* pool. If it is non-NULL, the new pool will inherit all
* of its parent pool's attributes, except the apr_pool_t will
* be a sub-pool.
*/
#if defined(DOXYGEN)
APR_DECLARE(apr_status_t) apr_pool_create(apr_pool_t **newpool,
apr_pool_t *parent);
#else
#if APR_POOL_DEBUG
#define apr_pool_create(newpool, parent) \
apr_pool_create_ex_debug(newpool, parent, NULL, NULL, \
APR_POOL__FILE_LINE__)
#else
#define apr_pool_create(newpool, parent) \
apr_pool_create_ex(newpool, parent, NULL, NULL)
#endif
#endif
/** @deprecated @see apr_pool_create_ex */
#if APR_POOL_DEBUG
#define apr_pool_sub_make(newpool, parent, abort_fn) \
(void)apr_pool_create_ex_debug(newpool, parent, abort_fn, \
NULL, \
APR_POOL__FILE_LINE__)
#else
#define apr_pool_sub_make(newpool, parent, abort_fn) \
(void)apr_pool_create_ex(newpool, parent, abort_fn, NULL)
#endif
/**
* Find the pools allocator
* @param pool The pool to get the allocator from.
*/
APR_DECLARE(apr_allocator_t *) apr_pool_allocator_get(apr_pool_t *pool);
/**
* Clear all memory in the pool and run all the cleanups. This also destroys all
* subpools.
* @param p The pool to clear
* @remark This does not actually free the memory, it just allows the pool
* to re-use this memory for the next allocation.
* @see apr_pool_destroy()
*/
APR_DECLARE(void) apr_pool_clear(apr_pool_t *p);
/**
* Debug version of apr_pool_clear.
* @param p See: apr_pool_clear.
* @param file_line Where the function is called from.
* This is usually APR_POOL__FILE_LINE__.
* @remark Only available when APR_POOL_DEBUG is defined.
* Call this directly if you have you apr_pool_clear
* calls in a wrapper function and wish to override
* the file_line argument to reflect the caller of
* your wrapper function. If you do not have
* apr_pool_clear in a wrapper, trust the macro
* and don't call apr_pool_destroy_clear directly.
*/
APR_DECLARE(void) apr_pool_clear_debug(apr_pool_t *p,
const char *file_line);
#if APR_POOL_DEBUG
#define apr_pool_clear(p) \
apr_pool_clear_debug(p, APR_POOL__FILE_LINE__)
#endif
/**
* Destroy the pool. This takes similar action as apr_pool_clear() and then
* frees all the memory.
* @param p The pool to destroy
* @remark This will actually free the memory
*/
APR_DECLARE(void) apr_pool_destroy(apr_pool_t *p);
/**
* Debug version of apr_pool_destroy.
* @param p See: apr_pool_destroy.
* @param file_line Where the function is called from.
* This is usually APR_POOL__FILE_LINE__.
* @remark Only available when APR_POOL_DEBUG is defined.
* Call this directly if you have you apr_pool_destroy
* calls in a wrapper function and wish to override
* the file_line argument to reflect the caller of
* your wrapper function. If you do not have
* apr_pool_destroy in a wrapper, trust the macro
* and don't call apr_pool_destroy_debug directly.
*/
APR_DECLARE(void) apr_pool_destroy_debug(apr_pool_t *p,
const char *file_line);
#if APR_POOL_DEBUG
#define apr_pool_destroy(p) \
apr_pool_destroy_debug(p, APR_POOL__FILE_LINE__)
#endif
/*
* Memory allocation
*/
/**
* Allocate a block of memory from a pool
* @param p The pool to allocate from
* @param size The amount of memory to allocate
* @return The allocated memory
*/
APR_DECLARE(void *) apr_palloc(apr_pool_t *p, apr_size_t size);
/**
* Debug version of apr_palloc
* @param p See: apr_palloc
* @param size See: apr_palloc
* @param file_line Where the function is called from.
* This is usually APR_POOL__FILE_LINE__.
* @return See: apr_palloc
*/
APR_DECLARE(void *) apr_palloc_debug(apr_pool_t *p, apr_size_t size,
const char *file_line);
#if APR_POOL_DEBUG
#define apr_palloc(p, size) \
apr_palloc_debug(p, size, APR_POOL__FILE_LINE__)
#endif
/**
* Allocate a block of memory from a pool and set all of the memory to 0
* @param p The pool to allocate from
* @param size The amount of memory to allocate
* @return The allocated memory
*/
#if defined(DOXYGEN)
APR_DECLARE(void *) apr_pcalloc(apr_pool_t *p, apr_size_t size);
#elif !APR_POOL_DEBUG
#define apr_pcalloc(p, size) memset(apr_palloc(p, size), 0, size)
#endif
/**
* Debug version of apr_pcalloc
* @param p See: apr_pcalloc
* @param size See: apr_pcalloc
* @param file_line Where the function is called from.
* This is usually APR_POOL__FILE_LINE__.
* @return See: apr_pcalloc
*/
APR_DECLARE(void *) apr_pcalloc_debug(apr_pool_t *p, apr_size_t size,
const char *file_line);
#if APR_POOL_DEBUG
#define apr_pcalloc(p, size) \
apr_pcalloc_debug(p, size, APR_POOL__FILE_LINE__)
#endif
/*
* Pool Properties
*/
/**
* Set the function to be called when an allocation failure occurs.
* @remark If the program wants APR to exit on a memory allocation error,
* then this function can be called to set the callback to use (for
* performing cleanup and then exiting). If this function is not called,
* then APR will return an error and expect the calling program to
* deal with the error accordingly.
*/
APR_DECLARE(void) apr_pool_abort_set(apr_abortfunc_t abortfunc,
apr_pool_t *pool);
/** @deprecated @see apr_pool_abort_set */
APR_DECLARE(void) apr_pool_set_abort(apr_abortfunc_t abortfunc,
apr_pool_t *pool);
/**
* Get the abort function associated with the specified pool.
* @param pool The pool for retrieving the abort function.
* @return The abort function for the given pool.
*/
APR_DECLARE(apr_abortfunc_t) apr_pool_abort_get(apr_pool_t *pool);
/** @deprecated @see apr_pool_abort_get */
APR_DECLARE(apr_abortfunc_t) apr_pool_get_abort(apr_pool_t *pool);
/**
* Get the parent pool of the specified pool.
* @param pool The pool for retrieving the parent pool.
* @return The parent of the given pool.
*/
APR_DECLARE(apr_pool_t *) apr_pool_parent_get(apr_pool_t *pool);
/** @deprecated @see apr_pool_parent_get */
APR_DECLARE(apr_pool_t *) apr_pool_get_parent(apr_pool_t *pool);
/**
* Determine if pool a is an ancestor of pool b
* @param a The pool to search
* @param b The pool to search for
* @return True if a is an ancestor of b, NULL is considered an ancestor
* of all pools.
*/
APR_DECLARE(int) apr_pool_is_ancestor(apr_pool_t *a, apr_pool_t *b);
/**
* Tag a pool (give it a name)
* @param pool The pool to tag
* @param tag The tag
*/
APR_DECLARE(void) apr_pool_tag(apr_pool_t *pool, const char *tag);
/*
* User data management
*/
/**
* Set the data associated with the current pool
* @param data The user data associated with the pool.
* @param key The key to use for association
* @param cleanup The cleanup program to use to cleanup the data (NULL if none)
* @param pool The current pool
* @warning The data to be attached to the pool should have a life span
* at least as long as the pool it is being attached to.
*
* Users of APR must take EXTREME care when choosing a key to
* use for their data. It is possible to accidentally overwrite
* data by choosing a key that another part of the program is using.
* Therefore it is advised that steps are taken to ensure that unique
* keys are used for all of the userdata objects in a particular pool
* (the same key in two different pools or a pool and one of its
* subpools is okay) at all times. Careful namespace prefixing of
* key names is a typical way to help ensure this uniqueness.
*/
APR_DECLARE(apr_status_t) apr_pool_userdata_set(
const void *data,
const char *key,
apr_status_t (*cleanup)(void *),
apr_pool_t *pool);
/**
* Set the data associated with the current pool
* @param data The user data associated with the pool.
* @param key The key to use for association
* @param cleanup The cleanup program to use to cleanup the data (NULL if none)
* @param pool The current pool
* @note same as apr_pool_userdata_set(), except that this version doesn't
* make a copy of the key (this function is useful, for example, when
* the key is a string literal)
* @warning This should NOT be used if the key could change addresses by
* any means between the apr_pool_userdata_setn() call and a
* subsequent apr_pool_userdata_get() on that key, such as if a
* static string is used as a userdata key in a DSO and the DSO could
* be unloaded and reloaded between the _setn() and the _get(). You
* MUST use apr_pool_userdata_set() in such cases.
* @warning More generally, the key and the data to be attached to the
* pool should have a life span at least as long as the pool itself.
*
*/
APR_DECLARE(apr_status_t) apr_pool_userdata_setn(
const void *data,
const char *key,
apr_status_t (*cleanup)(void *),
apr_pool_t *pool);
/**
* Return the data associated with the current pool.
* @param data The user data associated with the pool.
* @param key The key for the data to retrieve
* @param pool The current pool.
*/
APR_DECLARE(apr_status_t) apr_pool_userdata_get(void **data, const char *key,
apr_pool_t *pool);
/*
* Cleanup
*
* Cleanups are performed in the reverse order they were registered. That is:
* Last In, First Out.
*/
/**
* Register a function to be called when a pool is cleared or destroyed
* @param p The pool register the cleanup with
* @param data The data to pass to the cleanup function.
* @param plain_cleanup The function to call when the pool is cleared
* or destroyed
* @param child_cleanup The function to call when a child process is being
* shutdown - this function is called in the child, obviously!
*/
APR_DECLARE(void) apr_pool_cleanup_register(
apr_pool_t *p,
const void *data,
apr_status_t (*plain_cleanup)(void *),
apr_status_t (*child_cleanup)(void *));
/**
* Remove a previously registered cleanup function
* @param p The pool remove the cleanup from
* @param data The data to remove from cleanup
* @param cleanup The function to remove from cleanup
* @remarks For some strange reason only the plain_cleanup is handled by this
* function
*/
APR_DECLARE(void) apr_pool_cleanup_kill(apr_pool_t *p, const void *data,
apr_status_t (*cleanup)(void *));
/**
* Replace the child cleanup of a previously registered cleanup
* @param p The pool of the registered cleanup
* @param data The data of the registered cleanup
* @param plain_cleanup The plain cleanup function of the registered cleanup
* @param child_cleanup The function to register as the child cleanup
*/
APR_DECLARE(void) apr_pool_child_cleanup_set(
apr_pool_t *p,
const void *data,
apr_status_t (*plain_cleanup)(void *),
apr_status_t (*child_cleanup)(void *));
/**
* Run the specified cleanup function immediately and unregister it. Use
* @a data instead of the data that was registered with the cleanup.
* @param p The pool remove the cleanup from
* @param data The data to remove from cleanup
* @param cleanup The function to remove from cleanup
*/
APR_DECLARE(apr_status_t) apr_pool_cleanup_run(
apr_pool_t *p,
void *data,
apr_status_t (*cleanup)(void *));
/**
* An empty cleanup function
* @param data The data to cleanup
*/
APR_DECLARE_NONSTD(apr_status_t) apr_pool_cleanup_null(void *data);
/* Preparing for exec() --- close files, etc., but *don't* flush I/O
* buffers, *don't* wait for subprocesses, and *don't* free any memory.
*/
/**
* Run all of the child_cleanups, so that any unnecessary files are
* closed because we are about to exec a new program
*/
APR_DECLARE(void) apr_pool_cleanup_for_exec(void);
/**
* @defgroup PoolDebug Pool Debugging functions.
*
* pools have nested lifetimes -- sub_pools are destroyed when the
* parent pool is cleared. We allow certain liberties with operations
* on things such as tables (and on other structures in a more general
* sense) where we allow the caller to insert values into a table which
* were not allocated from the table's pool. The table's data will
* remain valid as long as all the pools from which its values are
* allocated remain valid.
*
* For example, if B is a sub pool of A, and you build a table T in
* pool B, then it's safe to insert data allocated in A or B into T
* (because B lives at most as long as A does, and T is destroyed when
* B is cleared/destroyed). On the other hand, if S is a table in
* pool A, it is safe to insert data allocated in A into S, but it
* is *not safe* to insert data allocated from B into S... because
* B can be cleared/destroyed before A is (which would leave dangling
* pointers in T's data structures).
*
* In general we say that it is safe to insert data into a table T
* if the data is allocated in any ancestor of T's pool. This is the
* basis on which the APR_POOL_DEBUG code works -- it tests these ancestor
* relationships for all data inserted into tables. APR_POOL_DEBUG also
* provides tools (apr_pool_find, and apr_pool_is_ancestor) for other
* folks to implement similar restrictions for their own data
* structures.
*
* However, sometimes this ancestor requirement is inconvenient --
* sometimes we're forced to create a sub pool (such as through
* apr_sub_req_lookup_uri), and the sub pool is guaranteed to have
* the same lifetime as the parent pool. This is a guarantee implemented
* by the *caller*, not by the pool code. That is, the caller guarantees
* they won't destroy the sub pool individually prior to destroying the
* parent pool.
*
* In this case the caller must call apr_pool_join() to indicate this
* guarantee to the APR_POOL_DEBUG code. There are a few examples spread
* through the standard modules.
*
* These functions are only implemented when #APR_POOL_DEBUG is set.
*
* @{
*/
#if APR_POOL_DEBUG || defined(DOXYGEN)
/**
* Guarantee that a subpool has the same lifetime as the parent.
* @param p The parent pool
* @param sub The subpool
*/
APR_DECLARE(void) apr_pool_join(apr_pool_t *p, apr_pool_t *sub);
/**
* Find a pool from something allocated in it.
* @param mem The thing allocated in the pool
* @return The pool it is allocated in
*/
APR_DECLARE(apr_pool_t *) apr_pool_find(const void *mem);
/**
* Report the number of bytes currently in the pool
* @param p The pool to inspect
* @param recurse Recurse/include the subpools' sizes
* @return The number of bytes
*/
APR_DECLARE(apr_size_t) apr_pool_num_bytes(apr_pool_t *p, int recurse);
/**
* Lock a pool
* @param pool The pool to lock
* @param flag The flag
*/
APR_DECLARE(void) apr_pool_lock(apr_pool_t *pool, int flag);
/* @} */
#else /* APR_POOL_DEBUG or DOXYGEN */
#ifdef apr_pool_join
#undef apr_pool_join
#endif
#define apr_pool_join(a,b)
#ifdef apr_pool_lock
#undef apr_pool_lock
#endif
#define apr_pool_lock(pool, lock)
#endif /* APR_POOL_DEBUG or DOXYGEN */
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* !APR_POOLS_H */