server/util_mutex.c

   1 /* Licensed to the Apache Software Foundation (ASF) under one or more
   2  * contributor license agreements.  See the NOTICE file distributed with
   3  * this work for additional information regarding copyright ownership.
   4  * The ASF licenses this file to You under the Apache License, Version 2.0
   5  * (the "License"); you may not use this file except in compliance with
   6  * the License.  You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /*
  18  * util_mutex.c: Useful functions for determining allowable
  19  *               mutexes and mutex settings
  20  */
  21
  22
  23 #include "apr.h"
  24 #include "apr_strings.h"
  25 #include "apr_lib.h"
  26
  27 #define APR_WANT_STRFUNC
  28 #include "apr_want.h"
  29
  30 #include "ap_config.h"
  31 #include "httpd.h"
  32 #include "http_main.h"
  33 #include "http_config.h"
  34 #include "util_mutex.h"
  35
  36 AP_DECLARE(apr_status_t) ap_parse_mutex(const char *arg, apr_pool_t *pool,
  37                                         apr_lockmech_e *mutexmech,
  38                                         const char **mutexfile)
  39 {
  40     /* Split arg into meth and file */
  41     char *meth = apr_pstrdup(pool, arg);
  42     char *file = strchr(meth, ':');
  43     if (file) {
  44         *(file++) = '\0';
  45         if (!*file) {
  46             file = NULL;
  47         }
  48     }
  49
  50     if (!strcasecmp(meth, "none") || !strcasecmp(meth, "no")) {
  51         return APR_ENOLOCK;
  52     }
  53
  54     /* APR determines temporary filename unless overridden below,
  55      * we presume file indicates an mutexfile is a file path
  56      * unless the method sets mutexfile=file and NULLs file
  57      */
  58     *mutexfile = NULL;
  59
  60     /* NOTE: previously, 'yes' implied 'sem' */
  61     if (!strcasecmp(meth, "default") || !strcasecmp(meth, "yes")) {
  62         *mutexmech = APR_LOCK_DEFAULT;
  63     }
  64 #if APR_HAS_FCNTL_SERIALIZE
  65     else if (!strcasecmp(meth, "fcntl") || !strcasecmp(meth, "file")) {
  66         *mutexmech = APR_LOCK_FCNTL;
  67     }
  68 #endif
  69 #if APR_HAS_FLOCK_SERIALIZE
  70     else if (!strcasecmp(meth, "flock") || !strcasecmp(meth, "file")) {
  71         *mutexmech = APR_LOCK_FLOCK;
  72     }
  73 #endif
  74 #if APR_HAS_POSIXSEM_SERIALIZE
  75     else if (!strcasecmp(meth, "posixsem") || !strcasecmp(meth, "sem")) {
  76         *mutexmech = APR_LOCK_POSIXSEM;
  77         /* Posix/SysV semaphores aren't file based, use the literal name
  78          * if provided and fall back on APR's default if not.  Today, APR
  79          * will ignore it, but once supported it has an absurdly short limit.
  80          */
  81         if (file) {
  82             *mutexfile = apr_pstrdup(pool, file);
  83
  84             file = NULL;
  85         }
  86     }
  87 #endif
  88 #if APR_HAS_SYSVSEM_SERIALIZE && !defined(PERCHILD_MPM)
  89     else if (!strcasecmp(meth, "sysvsem") || !strcasecmp(meth, "sem")) {
  90         *mutexmech = APR_LOCK_SYSVSEM;
  91     }
  92 #endif
  93 #if APR_HAS_PROC_PTHREAD_SERIALIZE
  94     else if (!strcasecmp(meth, "pthread")) {
  95         *mutexmech = APR_LOCK_PROC_PTHREAD;
  96     }
  97 #endif
  98     else {
  99         return APR_ENOTIMPL;
 100     }
 101
 102     /* Unless the method above assumed responsibility for setting up
 103      * mutexfile and NULLing out file, presume it is a file we
 104      * are looking to use
 105      */
 106     if (file) {
 107         *mutexfile = ap_server_root_relative(pool, file);
 108         if (!*mutexfile) {
 109             return APR_BADARG;
 110         }
 111     }
 112
 113     return APR_SUCCESS;
 114 }