src/afsweb/apache_includes/alloc.h

   1
   2 /* ====================================================================
   3  * Copyright (c) 1995-1997 The Apache Group.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the Apache Group
  20  *    for use in the Apache HTTP server project (http://www.apache.org/)."
  21  *
  22  * 4. The names "Apache Server" and "Apache Group" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission.
  25  *
  26  * 5. Redistributions of any form whatsoever must retain the following
  27  *    acknowledgment:
  28  *    "This product includes software developed by the Apache Group
  29  *    for use in the Apache HTTP server project (http://www.apache.org/)."
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
  32  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  34  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
  35  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  36  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  37  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  38  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  41  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  42  * OF THE POSSIBILITY OF SUCH DAMAGE.
  43  * ====================================================================
  44  *
  45  * This software consists of voluntary contributions made by many
  46  * individuals on behalf of the Apache Group and was originally based
  47  * on public domain software written at the National Center for
  48  * Supercomputing Applications, University of Illinois, Urbana-Champaign.
  49  * For more information on the Apache Group and the Apache HTTP server
  50  * project, please see <http://www.apache.org/>.
  51  *
  52  */
  53
  54 /*
  55  * Resource allocation routines...
  56  *
  57  * designed so that we don't have to keep track of EVERYTHING so that
  58  * it can be explicitly freed later (a fundamentally unsound strategy ---
  59  * particularly in the presence of die()).
  60  *
  61  * Instead, we maintain pools, and allocate items (both memory and I/O
  62  * handlers) from the pools --- currently there are two, one for per
  63  * transaction info, and one for config info.  When a transaction is over,
  64  * we can delete everything in the per-transaction pool without fear, and
  65  * without thinking too hard about it either.
  66  *
  67  * rst
  68  */
  69
  70 /* Arenas for configuration info and transaction info
  71  * --- actual layout of the pool structure is private to
  72  * alloc.c.
  73  */
  74
  75 typedef struct pool pool;
  76
  77 extern pool *permanent_pool;
  78 void init_alloc();              /* Set up everything */
  79 pool *make_sub_pool(pool *);    /* All pools are subpools of permanent_pool */
  80 void destroy_pool(pool *);
  81
  82 /* Clearing out EVERYTHING in an pool... destroys any sub-pools */
  83
  84 void clear_pool(struct pool *);
  85
  86 /* Preparing for exec() --- close files, etc., but *don't* flush I/O
  87  * buffers, *don't* wait for subprocesses, and *don't* free any memory.
  88  */
  89
  90 void cleanup_for_exec();
  91
  92 /* routines to allocate memory from an pool... */
  93
  94 void *palloc(struct pool *, int nbytes);
  95 void *pcalloc(struct pool *, int nbytes);
  96 extern char *pstrdup(struct pool *, const char *s);
  97 extern char *pstrndup(struct pool *, const char *s, int n);
  98 char *pstrcat(struct pool *, ...);      /* all '...' must be char* */
  99
 100 /* array and alist management... keeping lists of things.
 101  * Common enough to want common support code ...
 102  */
 103
 104 typedef struct {
 105     pool *pool;
 106     int elt_size;
 107     int nelts;
 108     int nalloc;
 109     char *elts;
 110 } array_header;
 111
 112 array_header *make_array(pool * p, int nelts, int elt_size);
 113 void *push_array(array_header *);
 114 void array_cat(array_header * dst, const array_header * src);
 115 array_header *append_arrays(pool *, const array_header *,
 116                             const array_header *);
 117
 118 /* copy_array copies the *entire* array.  copy_array_hdr just copies
 119  * the header, and arranges for the elements to be copied if (and only
 120  * if) the code subsequently does a push or arraycat.
 121  */
 122
 123 array_header *copy_array(pool * p, const array_header * src);
 124 array_header *copy_array_hdr(pool * p, const array_header * src);
 125
 126
 127 /* Tables.  Implemented alist style, for now, though we try to keep
 128  * it so that imposing a hash table structure on top in the future
 129  * wouldn't be *too* hard...
 130  *
 131  * Note that key comparisons for these are case-insensitive, largely
 132  * because that's what's appropriate and convenient everywhere they're
 133  * currently being used...
 134  */
 135
 136 typedef array_header table;
 137
 138 typedef struct {
 139     char *key;                  /* maybe NULL in future;
 140                                  * check when iterating thru table_elts
 141                                  */
 142     char *val;
 143 } table_entry;
 144
 145 table *make_table(pool * p, int nelts);
 146 table *copy_table(pool * p, const table *);
 147 void clear_table(table *);
 148 char *table_get(const table *, const char *);
 149 void table_set(table *, const char *name, const char *val);
 150 void table_merge(table *, const char *name, const char *more_val);
 151 void table_unset(table *, const char *key);
 152 void table_add(table *, const char *name, const char *val);
 153 void table_do(int (*comp) (void *, const char *, const char *), void *rec,
 154               const table * t, ...);
 155
 156 table *overlay_tables(pool * p, const table * overlay, const table * base);
 157
 158 array_header *table_elts(table *);
 159
 160 #define is_empty_table(t) (((t) == NULL)||((t)->nelts == 0))
 161
 162 /* routines to remember allocation of other sorts of things...
 163  * generic interface first.  Note that we want to have two separate
 164  * cleanup functions in the general case, one for exec() preparation,
 165  * to keep CGI scripts and the like from inheriting access to things
 166  * they shouldn't be able to touch, and one for actually cleaning up,
 167  * when the actual server process wants to get rid of the thing,
 168  * whatever it is.
 169  *
 170  * kill_cleanup disarms a cleanup, presumably because the resource in
 171  * question has been closed, freed, or whatever, and it's scarce
 172  * enough to want to reclaim (e.g., descriptors).  It arranges for the
 173  * resource not to be cleaned up a second time (it might have been
 174  * reallocated).  run_cleanup does the same, but runs it first.
 175  *
 176  * Cleanups are identified for purposes of finding & running them off by the
 177  * plain_cleanup and data, which should presumably be unique.
 178  *
 179  * NB any code which invokes register_cleanup or kill_cleanup directly
 180  * is a critical section which should be guarded by block_alarms() and
 181  * unblock_alarms() below...
 182  */
 183
 184 void register_cleanup(pool * p, void *data, void (*plain_cleanup) (void *),
 185                       void (*child_cleanup) (void *));
 186
 187 void kill_cleanup(pool * p, void *data, void (*plain_cleanup) (void *));
 188 void run_cleanup(pool * p, void *data, void (*cleanup) (void *));
 189
 190 /* The time between when a resource is actually allocated, and when it
 191  * its cleanup is registered is a critical section, during which the
 192  * resource could leak if we got interrupted or timed out.  So, anything
 193  * which registers cleanups should bracket resource allocation and the
 194  * cleanup registry with these.  (This is done internally by run_cleanup).
 195  *
 196  * NB they are actually implemented in http_main.c, since they are bound
 197  * up with timeout handling in general...
 198  */
 199
 200 extern void block_alarms();
 201 extern void unblock_alarms();
 202
 203 /* Common cases which want utility support..
 204  * the note_cleanups_for_foo routines are for
 205  */
 206
 207 FILE *pfopen(struct pool *, const char *name, const char *fmode);
 208 FILE *pfdopen(struct pool *, int fd, const char *fmode);
 209 int popenf(struct pool *, const char *name, int flg, int mode);
 210
 211 void note_cleanups_for_file(pool *, FILE *);
 212 void note_cleanups_for_fd(pool *, int);
 213 void kill_cleanups_for_fd(pool * p, int fd);
 214
 215 regex_t *pregcomp(pool * p, const char *pattern, int cflags);
 216 void pregfree(pool * p, regex_t * reg);
 217
 218 /* routines to note closes... file descriptors are constrained enough
 219  * on some systems that we want to support this.
 220  */
 221
 222 int pfclose(struct pool *, FILE *);
 223 int pclosef(struct pool *, int fd);
 224
 225 /* ... even child processes (which we may want to wait for,
 226  * or to kill outright, on unexpected termination).
 227  *
 228  * spawn_child is a utility routine which handles an awful lot of
 229  * the rigamarole associated with spawning a child --- it arranges
 230  * for pipes to the child's stdin and stdout, if desired (if not,
 231  * set the associated args to NULL).  It takes as args a function
 232  * to call in the child, and an argument to be passed to the function.
 233  */
 234
 235 enum kill_conditions { kill_never, kill_always, kill_after_timeout,
 236     just_wait
 237 };
 238
 239 int spawn_child_err(pool *, void (*)(void *), void *, enum kill_conditions,
 240                     FILE ** pipe_in, FILE ** pipe_out, FILE ** pipe_err);
 241 #define spawn_child(p,f,v,k,in,out) spawn_child_err(p,f,v,k,in,out,NULL)
 242
 243 /* magic numbers --- min free bytes to consider a free pool block useable,
 244  * and the min amount to allocate if we have to go to malloc() */
 245
 246 #define BLOCK_MINFREE 4096
 247 #define BLOCK_MINALLOC 8192
 248
 249 /* Finally, some accounting */
 250
 251 long bytes_in_pool(pool * p);
 252 long bytes_in_free_blocks();