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Celestin Apprentice 4
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Apache 1.0
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alloc.h
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1995-12-04
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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();