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/* ====================================================================

 * Copyright (c) 1995 The Apache Group.  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. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the Apache Group

 *    for use in the Apache HTTP server project (http://www.apache.org/)."

 *

 * 4. The names "Apache Server" and "Apache Group" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission.

 *

 * 5. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the Apache Group

 *    for use in the Apache HTTP server project (http://www.apache.org/)."

 *

 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY

 * EXPRESSED 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 APACHE GROUP OR

 * IT'S CONTRIBUTORS 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.

 * ====================================================================

 *

 * This software consists of voluntary contributions made by many

 * individuals on behalf of the Apache Group and was originally based

 * on public domain software written at the National Center for

 * Supercomputing Applications, University of Illinois, Urbana-Champaign.

 * For more information on the Apache Group and the Apache HTTP server

 * project, please see <http://www.apache.org/>.

 *

 */

/*

 * 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 pool without fear, and

 * without thinking too hard about it either.

 *

 * rst

 */

/* Arenas for configuration info and transaction info

 * --- actual layout of the pool structure is private to 

 * alloc.c.  

 */

typedef struct pool pool;

extern pool *permanent_pool;

void init_alloc();		/* Set up everything */

pool *make_sub_pool (pool *);	/* All pools are subpools of permanent_pool */

void destroy_pool (pool *);

/* Clearing out EVERYTHING in an pool... destroys any sub-pools */

void clear_pool (struct pool *);

/* Preparing for exec() --- close files, etc., but *don't* flush I/O

 * buffers, *don't* wait for subprocesses, and *don't* free any memory.

 */

void cleanup_for_exec ();

/* routines to allocate memory from an pool... */

void *palloc(struct pool *, int nbytes);

void *pcalloc(struct pool *, int nbytes);

char *pstrdup(struct pool *, char *s);

char *pstrcat(struct pool *, ...); /* all '...' must be char* */

/* array and alist management... keeping lists of things.

 * Common enough to want common support code ...

 */

typedef struct {

    pool *pool;

    int elt_size;

    int nelts;

    int nalloc;

    char *elts;

} array_header;

array_header *make_array (pool *p, int nelts, int elt_size);

void *push_array (array_header *);

void array_cat (array_header *dst, array_header *src);

array_header *append_arrays (pool *, array_header *, array_header *);

/* copy_array copies the *entire* array.  copy_array_hdr just copies

 * the header, and arranges for the elements to be copied if (and only

 * if) the code subsequently does a push or arraycat.

 */

array_header *copy_array (pool *p, array_header *src);

array_header *copy_array_hdr (pool *p, array_header *src);

/* Tables.  Implemented alist style, for now, though we try to keep

 * it so that imposing a hash table structure on top in the future

 * wouldn't be *too* hard...

 *

 * Note that key comparisons for these are case-insensitive, largely

 * because that's what's appropriate and convenient everywhere they're

 * currently being used...

 */

typedef array_header table;     

typedef struct {

    char *key;			/* maybe NULL in future;

				 * check when iterating thru table_elts

				 */

    char *val;

} table_entry;

table *make_table (pool *p, int nelts);

table *copy_table (pool *p, table *);     

char *table_get (table *, char *);

void table_set (table *, char *name, char *val);

void table_merge (table *, char *name, char *more_val);

table *overlay_tables (pool *p, table *overlay, table *base);     

array_header *table_elts (table *);     

/* routines to remember allocation of other sorts of things...

 * generic interface first.  Note that we want to have two separate

 * cleanup functions in the general case, one for exec() preparation,

 * to keep CGI scripts and the like from inheriting access to things

 * they shouldn't be able to touch, and one for actually cleaning up,

 * when the actual server process wants to get rid of the thing,

 * whatever it is.  

 *

 * kill_cleanup disarms a cleanup, presumably because the resource in

 * question has been closed, freed, or whatever, and it's scarce

 * enough to want to reclaim (e.g., descriptors).  It arranges for the

 * resource not to be cleaned up a second time (it might have been

 * reallocated).  run_cleanup does the same, but runs it first.

 *

 * Cleanups are identified for purposes of finding & running them off by the

 * plain_cleanup and data, which should presumably be unique.

 *

 * NB any code which invokes register_cleanup or kill_cleanup directly

 * is a critical section which should be guarded by block_alarms() and

 * unblock_alarms() below...

 */

void register_cleanup (pool *p, void *data,

		       void (*plain_cleanup)(void *),

		       void (*child_cleanup)(void *));

void kill_cleanup (pool *p, void *data, void (*plain_cleanup)(void *));

/* The time between when a resource is actually allocated, and when it

 * its cleanup is registered is a critical section, during which the

 * resource could leak if we got interrupted or timed out.  So, anything

 * which registers cleanups should bracket resource allocation and the

 * cleanup registry with these.  (This is done internally by run_cleanup).

 *

 * NB they are actually implemented in http_main.c, since they are bound

 * up with timeout handling in general...

 */

extern void block_alarms();

extern void unblock_alarms();

/* Common cases which want utility support..

 * the note_cleanups_for_foo routines are for 

 */

FILE *pfopen(struct pool *, char *name, char *fmode);

FILE *pfdopen(struct pool *, int fd, char *fmode);

int popenf(struct pool *, char *name, int flg, int mode); 

void note_cleanups_for_file (pool *, FILE *);

void note_cleanups_for_fd (pool *, int);

/* routines to note closes... file descriptors are constrained enough

 * on some systems that we want to support this.

 */

int pfclose(struct pool *, FILE *);

int pclosef(struct pool *, int fd);

/* ... even child processes (which we may want to wait for,

 * or to kill outright, on unexpected termination).

 *

 * spawn_child is a utility routine which handles an awful lot of

 * the rigamarole associated with spawning a child --- it arranges

 * for pipes to the child's stdin and stdout, if desired (if not,

 * set the associated args to NULL).  It takes as args a function

 * to call in the child, and an argument to be passed to the function.

 */

enum kill_conditions { kill_never, kill_always, kill_after_timeout, just_wait};

int spawn_child (pool *, void (*)(void *), void *,

		 enum kill_conditions, FILE **pipe_in, FILE **pipe_out);

/* magic numbers --- only one so far, min free bytes in a new pool block */

#define BLOCK_MINFREE 8192     

/* Finally, some accounting */

long bytes_in_pool(pool *p);

long bytes_in_free_blocks();