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/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as * applicable. * * 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: * <pre> * APR_POOL_DECLARE_ACCESSOR(file); * becomes: * APR_DECLARE(apr_pool_t *) apr_file_pool_get(apr_file_t *ob); * </pre> * @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 * * <pre> * | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | * --------------------------------- * | | | | | | | | x | General debug code enabled (useful 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 * </pre> */ #if defined(APR_POOL_DEBUG) /* If APR_POOL_DEBUG is blank, we get 1; if it is a number, we get -1. */ #if (APR_POOL_DEBUG - APR_POOL_DEBUG -1 == 1) #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 /** * 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); /** * 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); /** * 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); /** * 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. * @remark if compiled with APR_POOL_DEBUG, this function will also * return true if A is a pool which has been guaranteed by the caller * (using apr_pool_join) to have a lifetime at least as long as some * ancestor of pool B. */ 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); /** * @defgroup PoolCleanup Pool Cleanup Functions * * Cleanups are performed in the reverse order they were registered. That is: * Last In, First Out. A cleanup function can safely allocate memory from * the pool that is being cleaned up. It can also safely register additional * cleanups which will be run LIFO, directly after the current cleanup * terminates. Cleanups have to take caution in calling functions that * create subpools. Subpools, created during cleanup will NOT automatically * be cleaned up. In other words, cleanups are to clean up after themselves. * * @{ */ /** * 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 about * to exec - 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. * * The cleanup most recently registered with @a p having the same values of * @a data and @a cleanup will be removed. * * @param p The pool to remove the cleanup from * @param data The data of the registered 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 function of a previously registered cleanup. * * The cleanup most recently registered with @a p having the same values of * @a data and @a plain_cleanup will have the registered child cleanup * function replaced with @a child_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. * * The cleanup most recently registered with @a p having the same values of * @a data and @a cleanup will be removed and @a cleanup will be called * with @a data as the argument. * * @param p The pool to 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. * * Passed to apr_pool_cleanup_register() when no cleanup is required. * * @param data The data to cleanup, will not be used by this function. */ APR_DECLARE_NONSTD(apr_status_t) apr_pool_cleanup_null(void *data); /** * Run all registered child cleanups, in preparation for an exec() * call in a forked child -- close files, etc., but *don't* flush I/O * buffers, *don't* wait for subprocesses, and *don't* free any * memory. */ 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 it's necessary to create a sub pool where 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. * * 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 */