modules/metadata/mod_env.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 #include "apr.h"
  18 #include "apr_strings.h"
  19
  20 #if APR_HAVE_STDLIB_H
  21 #include <stdlib.h>
  22 #endif
  23
  24 #include "ap_config.h"
  25 #include "httpd.h"
  26 #include "http_config.h"
  27 #include "http_request.h"
  28 #include "http_log.h"
  29
  30 typedef struct {
  31     apr_table_t *vars;
  32     apr_table_t *unsetenv;
  33 } env_dir_config_rec;
  34
  35 module AP_MODULE_DECLARE_DATA env_module;
  36
  37 static void *create_env_dir_config(apr_pool_t *p, char *dummy)
  38 {
  39     env_dir_config_rec *conf = apr_palloc(p, sizeof(*conf));
  40
  41     conf->vars = apr_table_make(p, 10);
  42     conf->unsetenv = apr_table_make(p, 10);
  43
  44     return conf;
  45 }
  46
  47 static void *merge_env_dir_configs(apr_pool_t *p, void *basev, void *addv)
  48 {
  49     env_dir_config_rec *base = basev;
  50     env_dir_config_rec *add = addv;
  51     env_dir_config_rec *res = apr_palloc(p, sizeof(*res));
  52
  53     const apr_table_entry_t *elts;
  54     const apr_array_header_t *arr;
  55
  56     int i;
  57
  58     /*
  59      * res->vars = copy_table( p, base->vars );
  60      * foreach $unsetenv ( @add->unsetenv )
  61      *     table_unset( res->vars, $unsetenv );
  62      * foreach $element ( @add->vars )
  63      *     table_set( res->vars, $element.key, $element.val );
  64      *
  65      * add->unsetenv already removed the vars from add->vars,
  66      * if they preceeded the UnsetEnv directive.
  67      */
  68     res->vars = apr_table_copy(p, base->vars);
  69     res->unsetenv = NULL;
  70
  71     arr = apr_table_elts(add->unsetenv);
  72     if (arr) {
  73         elts = (const apr_table_entry_t *)arr->elts;
  74
  75         for (i = 0; i < arr->nelts; ++i) {
  76             apr_table_unset(res->vars, elts[i].key);
  77         }
  78     }
  79
  80     arr = apr_table_elts(add->vars);
  81     if (arr) {
  82         elts = (const apr_table_entry_t *)arr->elts;
  83
  84         for (i = 0; i < arr->nelts; ++i) {
  85             apr_table_setn(res->vars, elts[i].key, elts[i].val);
  86         }
  87     }
  88
  89     return res;
  90 }
  91
  92 static const char *add_env_module_vars_passed(cmd_parms *cmd, void *sconf_,
  93                                               const char *arg)
  94 {
  95     env_dir_config_rec *sconf = sconf_;
  96     apr_table_t *vars = sconf->vars;
  97     const char *env_var;
  98
  99     env_var = getenv(arg);
 100     if (env_var != NULL) {
 101         apr_table_setn(vars, arg, apr_pstrdup(cmd->pool, env_var));
 102     }
 103     else {
 104         ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server,
 105                      "PassEnv variable %s was undefined", arg);
 106     }
 107
 108     return NULL;
 109 }
 110
 111 static const char *add_env_module_vars_set(cmd_parms *cmd, void *sconf_,
 112                                            const char *name, const char *value)
 113 {
 114     env_dir_config_rec *sconf = sconf_;
 115
 116     /* name is mandatory, value is optional.  no value means
 117      * set the variable to an empty string
 118      */
 119     apr_table_setn(sconf->vars, name, value ? value : "");
 120
 121     return NULL;
 122 }
 123
 124 static const char *add_env_module_vars_unset(cmd_parms *cmd, void *sconf_,
 125                                              const char *arg)
 126 {
 127     env_dir_config_rec *sconf = sconf_;
 128
 129     /* Always UnsetEnv FOO in the same context as {Set,Pass}Env FOO
 130      * only if this UnsetEnv follows the {Set,Pass}Env.  The merge
 131      * will only apply unsetenv to the parent env (main server).
 132      */
 133     apr_table_set(sconf->unsetenv, arg, NULL);
 134     apr_table_unset(sconf->vars, arg);
 135
 136     return NULL;
 137 }
 138
 139 static const command_rec env_module_cmds[] =
 140 {
 141 AP_INIT_ITERATE("PassEnv", add_env_module_vars_passed, NULL,
 142      OR_FILEINFO, "a list of environment variables to pass to CGI."),
 143 AP_INIT_TAKE12("SetEnv", add_env_module_vars_set, NULL,
 144      OR_FILEINFO, "an environment variable name and optional value to pass to CGI."),
 145 AP_INIT_ITERATE("UnsetEnv", add_env_module_vars_unset, NULL,
 146      OR_FILEINFO, "a list of variables to remove from the CGI environment."),
 147     {NULL},
 148 };
 149
 150 static int fixup_env_module(request_rec *r)
 151 {
 152     apr_table_t *e = r->subprocess_env;
 153     env_dir_config_rec *sconf = ap_get_module_config(r->per_dir_config,
 154                                                      &env_module);
 155     apr_table_t *vars = sconf->vars;
 156
 157     if (!apr_table_elts(sconf->vars)->nelts)
 158         return DECLINED;
 159
 160     r->subprocess_env = apr_table_overlay(r->pool, e, vars);
 161
 162     return OK;
 163 }
 164
 165 static void register_hooks(apr_pool_t *p)
 166 {
 167     ap_hook_fixups(fixup_env_module, NULL, NULL, APR_HOOK_MIDDLE);
 168 }
 169
 170 module AP_MODULE_DECLARE_DATA env_module =
 171 {
 172     STANDARD20_MODULE_STUFF,
 173     create_env_dir_config,      /* dir config creater */
 174     merge_env_dir_configs,      /* dir merger --- default is to override */
 175     NULL,                       /* server config */
 176     NULL,                       /* merge server configs */
 177     env_module_cmds,            /* command apr_table_t */
 178     register_hooks              /* register hooks */
 179 };