Adding upstream version 2.4.57.upstream/2.4.57

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 442 insertions, 0 deletions

diff --git a/modules/core/mod_so.c b/modules/core/mod_so.c
new file mode 100644
index 0000000..f5d18c1
--- /dev/null
+++ b/modules/core/mod_so.c
@@ -0,0 +1,442 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * This module is used to load Apache modules at runtime. This means that the
+ * server functionality can be extended without recompiling and even without
+ * taking the server down at all. Only a HUP or AP_SIG_GRACEFUL signal
+ * needs to be sent to the server to reload the dynamically loaded modules.
+ *
+ * To use, you'll first need to build your module as a shared library, then
+ * update your configuration (httpd.conf) to get the Apache core to load the
+ * module at start-up.
+ *
+ * The easiest way to build a module as a shared library is to use the
+ * `SharedModule' command in the Configuration file, instead of `AddModule'.
+ * You should also change the file extension from `.o' to `.so'. So, for
+ * example, to build the status module as a shared library edit Configuration
+ * and change
+ *   AddModule    modules/standard/mod_status.o
+ * to
+ *   SharedModule modules/standard/mod_status.so
+ *
+ * Run Configure and make. Now Apache's httpd binary will _not_ include
+ * mod_status. Instead a shared object called mod_status.so will be build, in
+ * the modules/standard directory. You can build most of the modules as shared
+ * libraries like this.
+ *
+ * To use the shared module, move the .so file(s) into an appropriate
+ * directory. You might like to create a directory called "modules" under you
+ * server root for this (e.g. /usr/local/httpd/modules).
+ *
+ * Then edit your conf/httpd.conf file, and add LoadModule lines. For
+ * example
+ *   LoadModule  status_module   modules/mod_status.so
+ *
+ * The first argument is the module's structure name (look at the end of the
+ * module source to find this). The second option is the path to the module
+ * file, relative to the server root.  Put these directives right at the top
+ * of your httpd.conf file.
+ *
+ * Now you can start Apache. A message will be logged at "debug" level to your
+ * error_log to confirm that the module(s) are loaded (use "LogLevel debug"
+ * directive to get these log messages).
+ *
+ * If you edit the LoadModule directives while the server is live you can get
+ * Apache to re-load the modules by sending it a HUP or AP_SIG_GRACEFUL
+ * signal as normal.  You can use this to dynamically change the capability
+ * of your server without bringing it down.
+ *
+ * Because currently there is only limited builtin support in the Configure
+ * script for creating the shared library files (`.so'), please consult your
+ * vendors cc(1), ld(1) and dlopen(3) manpages to find out the appropriate
+ * compiler and linker flags and insert them manually into the Configuration
+ * file under CFLAGS_SHLIB, LDFLAGS_SHLIB and LDFLAGS_SHLIB_EXPORT.
+ *
+ * If you still have problems figuring out the flags both try the paper
+ *     http://developer.netscape.com/library/documentation/enterprise
+ *                                          /unix/svrplug.htm#1013807
+ * or install a Perl 5 interpreter on your platform and then run the command
+ *
+ *     $ perl -V:usedl -V:ccdlflags -V:cccdlflags -V:lddlflags
+ *
+ * This gives you what type of dynamic loading Perl 5 uses on your platform
+ * and which compiler and linker flags Perl 5 uses to create the shared object
+ * files.
+ *
+ * Another location where you can find useful hints is the `ltconfig' script
+ * of the GNU libtool 1.2 package. Search for your platform name inside the
+ * various "case" constructs.
+ *
+ */
+
+#include "apr.h"
+#include "apr_dso.h"
+#include "apr_strings.h"
+#include "apr_errno.h"
+
+#include "ap_config.h"
+#include "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "http_core.h"
+
+#include "mod_so.h"
+
+module AP_MODULE_DECLARE_DATA so_module;
+
+
+/*
+ * Server configuration to keep track of actually
+ * loaded modules and the corresponding module name.
+ */
+
+typedef struct so_server_conf {
+    apr_array_header_t *loaded_modules;
+} so_server_conf;
+
+static void *so_sconf_create(apr_pool_t *p, server_rec *s)
+{
+    so_server_conf *soc;
+
+    soc = (so_server_conf *)apr_pcalloc(p, sizeof(so_server_conf));
+    soc->loaded_modules = apr_array_make(p, DYNAMIC_MODULE_LIMIT,
+                                     sizeof(ap_module_symbol_t));
+
+    return (void *)soc;
+}
+
+#ifndef NO_DLOPEN
+
+/*
+ * This is the cleanup for a loaded shared object. It unloads the module.
+ * This is called as a cleanup function from the core.
+ */
+
+static apr_status_t unload_module(void *data)
+{
+    ap_module_symbol_t *modi = (ap_module_symbol_t*)data;
+
+    /* only unload if module information is still existing */
+    if (modi->modp == NULL)
+        return APR_SUCCESS;
+
+    /* remove the module pointer from the core structure */
+    ap_remove_loaded_module(modi->modp);
+
+    /* destroy the module information */
+    modi->modp = NULL;
+    modi->name = NULL;
+    return APR_SUCCESS;
+}
+
+static const char *dso_load(cmd_parms *cmd, apr_dso_handle_t **modhandlep,
+                            const char *filename, const char **used_filename)
+{
+    int retry = 0;
+    const char *fullname = ap_server_root_relative(cmd->temp_pool, filename);
+    char my_error[256];
+    if (filename != NULL && ap_strchr_c(filename, '/') == NULL) {
+        /* retry on error without path to use dlopen()'s search path */
+        retry = 1;
+    }
+
+    if (fullname == NULL && !retry) {
+        return apr_psprintf(cmd->temp_pool, "Invalid %s path %s",
+                            cmd->cmd->name, filename);
+    }
+    *used_filename = fullname;
+    if (fullname && apr_dso_load(modhandlep, fullname, cmd->pool) == APR_SUCCESS) {
+        return NULL;
+    }
+    if (retry) {
+        *used_filename = filename;
+        if (apr_dso_load(modhandlep, filename, cmd->pool) == APR_SUCCESS)
+            return NULL;
+    }
+
+    return apr_pstrcat(cmd->temp_pool, "Cannot load ", filename,
+                        " into server: ",
+                        apr_dso_error(*modhandlep, my_error, sizeof(my_error)),
+                        NULL);
+}
+
+/*
+ * This is called for the directive LoadModule and actually loads
+ * a shared object file into the address space of the server process.
+ */
+
+static const char *load_module(cmd_parms *cmd, void *dummy,
+                               const char *modname, const char *filename)
+{
+    apr_dso_handle_t *modhandle;
+    apr_dso_handle_sym_t modsym;
+    module *modp;
+    const char *module_file;
+    so_server_conf *sconf;
+    ap_module_symbol_t *modi;
+    ap_module_symbol_t *modie;
+    int i;
+    const char *error;
+
+    /* we need to setup this value for dummy to make sure that we don't try
+     * to add a non-existent tree into the build when we return to
+     * execute_now.
+     */
+    *(ap_directive_t **)dummy = NULL;
+
+    /*
+     * check for already existing module
+     * If it already exists, we have nothing to do
+     * Check both dynamically-loaded modules and statically-linked modules.
+     */
+    sconf = (so_server_conf *)ap_get_module_config(cmd->server->module_config,
+                                                &so_module);
+    modie = (ap_module_symbol_t *)sconf->loaded_modules->elts;
+    for (i = 0; i < sconf->loaded_modules->nelts; i++) {
+        modi = &modie[i];
+        if (modi->name != NULL && strcmp(modi->name, modname) == 0) {
+            ap_log_perror(APLOG_MARK, APLOG_WARNING, 0, cmd->pool, APLOGNO(01574)
+                          "module %s is already loaded, skipping",
+                          modname);
+            return NULL;
+        }
+    }
+
+    for (i = 0; ap_preloaded_modules[i]; i++) {
+        const char *preload_name;
+        apr_size_t preload_len;
+        apr_size_t thismod_len;
+
+        modp = ap_preloaded_modules[i];
+
+        /* make sure we're comparing apples with apples
+         * make sure name of preloaded module is mod_FOO.c
+         * make sure name of structure being loaded is FOO_module
+         */
+
+        if (memcmp(modp->name, "mod_", 4)) {
+            continue;
+        }
+
+        preload_name = modp->name + strlen("mod_");
+        preload_len = strlen(preload_name) - 2;
+
+        if (strlen(modname) <= strlen("_module")) {
+            continue;
+        }
+        thismod_len = strlen(modname) - strlen("_module");
+        if (strcmp(modname + thismod_len, "_module")) {
+            continue;
+        }
+
+        if (thismod_len != preload_len) {
+            continue;
+        }
+
+        if (!memcmp(modname, preload_name, preload_len)) {
+            return apr_pstrcat(cmd->pool, "module ", modname,
+                               " is built-in and can't be loaded",
+                               NULL);
+        }
+    }
+
+    modi = apr_array_push(sconf->loaded_modules);
+    modi->name = modname;
+
+    /*
+     * Load the file into the Apache address space
+     */
+    error = dso_load(cmd, &modhandle, filename, &module_file);
+    if (error)
+        return error;
+    ap_log_perror(APLOG_MARK, APLOG_DEBUG, 0, cmd->pool, APLOGNO(01575)
+                 "loaded module %s from %s", modname, module_file);
+
+    /*
+     * Retrieve the pointer to the module structure through the module name:
+     * First with the hidden variant (prefix `AP_') and then with the plain
+     * symbol name.
+     */
+    if (apr_dso_sym(&modsym, modhandle, modname) != APR_SUCCESS) {
+        char my_error[256];
+
+        return apr_pstrcat(cmd->pool, "Can't locate API module structure `",
+                          modname, "' in file ", module_file, ": ",
+                          apr_dso_error(modhandle, my_error, sizeof(my_error)),
+                          NULL);
+    }
+    modp = (module*) modsym;
+    modp->dynamic_load_handle = (apr_dso_handle_t *)modhandle;
+    modi->modp = modp;
+
+    /*
+     * Make sure the found module structure is really a module structure
+     *
+     */
+    if (modp->magic != MODULE_MAGIC_COOKIE) {
+        return apr_psprintf(cmd->pool, "API module structure '%s' in file %s "
+                            "is garbled - expected signature %08lx but saw "
+                            "%08lx - perhaps this is not an Apache module DSO, "
+                            "or was compiled for a different Apache version?",
+                            modname, module_file,
+                            MODULE_MAGIC_COOKIE, modp->magic);
+    }
+
+    /*
+     * Add this module to the Apache core structures
+     */
+    error = ap_add_loaded_module(modp, cmd->pool, modname);
+    if (error) {
+        return error;
+    }
+
+    /*
+     * Register a cleanup in the config apr_pool_t (normally pconf). When
+     * we do a restart (or shutdown) this cleanup will cause the
+     * shared object to be unloaded.
+     */
+    apr_pool_cleanup_register(cmd->pool, modi, unload_module, apr_pool_cleanup_null);
+
+    /*
+     * Finally we need to run the configuration process for the module
+     */
+    ap_single_module_configure(cmd->pool, cmd->server, modp);
+
+    return NULL;
+}
+
+/*
+ * This implements the LoadFile directive and loads an arbitrary
+ * shared object file into the address space of the server process.
+ */
+
+static const char *load_file(cmd_parms *cmd, void *dummy, const char *filename)
+{
+    apr_dso_handle_t *handle;
+    const char *used_file, *error;
+
+    error = dso_load(cmd, &handle, filename, &used_file);
+    if (error)
+        return error;
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, APLOGNO(01576)
+                 "loaded file %s", used_file);
+
+    return NULL;
+}
+
+static module *ap_find_loaded_module_symbol(server_rec *s, const char *modname)
+{
+    so_server_conf *sconf;
+    ap_module_symbol_t *modi;
+    ap_module_symbol_t *modie;
+    int i;
+
+    sconf = (so_server_conf *)ap_get_module_config(s->module_config,
+                                                   &so_module);
+    modie = (ap_module_symbol_t *)sconf->loaded_modules->elts;
+
+    for (i = 0; i < sconf->loaded_modules->nelts; i++) {
+        modi = &modie[i];
+        if (modi->name != NULL && strcmp(modi->name, modname) == 0) {
+            return modi->modp;
+        }
+    }
+    return NULL;
+}
+
+static void dump_loaded_modules(apr_pool_t *p, server_rec *s)
+{
+    ap_module_symbol_t *modie;
+    ap_module_symbol_t *modi;
+    so_server_conf *sconf;
+    int i;
+    apr_file_t *out = NULL;
+
+    if (!ap_exists_config_define("DUMP_MODULES")) {
+        return;
+    }
+
+    apr_file_open_stdout(&out, p);
+
+    apr_file_printf(out, "Loaded Modules:\n");
+
+    sconf = (so_server_conf *)ap_get_module_config(s->module_config,
+                                                   &so_module);
+    for (i = 0; ; i++) {
+        modi = &ap_prelinked_module_symbols[i];
+        if (modi->name != NULL) {
+            apr_file_printf(out, " %s (static)\n", modi->name);
+        }
+        else {
+            break;
+        }
+    }
+
+    modie = (ap_module_symbol_t *)sconf->loaded_modules->elts;
+    for (i = 0; i < sconf->loaded_modules->nelts; i++) {
+        modi = &modie[i];
+        if (modi->name != NULL) {
+            apr_file_printf(out, " %s (shared)\n", modi->name);
+        }
+    }
+}
+
+#else /* not NO_DLOPEN */
+
+static const char *load_file(cmd_parms *cmd, void *dummy, const char *filename)
+{
+    ap_log_perror(APLOG_MARK, APLOG_STARTUP, 0, cmd->pool, APLOGNO(01577)
+                 "WARNING: LoadFile not supported on this platform");
+    return NULL;
+}
+
+static const char *load_module(cmd_parms *cmd, void *dummy,
+                               const char *modname, const char *filename)
+{
+    ap_log_perror(APLOG_MARK, APLOG_STARTUP, 0, cmd->pool, APLOGNO(01578)
+                 "WARNING: LoadModule not supported on this platform");
+    return NULL;
+}
+
+#endif /* NO_DLOPEN */
+
+static void register_hooks(apr_pool_t *p)
+{
+#ifndef NO_DLOPEN
+    APR_REGISTER_OPTIONAL_FN(ap_find_loaded_module_symbol);
+    ap_hook_test_config(dump_loaded_modules, NULL, NULL, APR_HOOK_MIDDLE);
+#endif
+}
+
+static const command_rec so_cmds[] = {
+    AP_INIT_TAKE2("LoadModule", load_module, NULL, RSRC_CONF | EXEC_ON_READ,
+      "a module name and the name of a shared object file to load it from"),
+    AP_INIT_ITERATE("LoadFile", load_file, NULL, RSRC_CONF  | EXEC_ON_READ,
+      "shared object file or library to load into the server at runtime"),
+    { NULL }
+};
+
+AP_DECLARE_MODULE(so) = {
+   STANDARD20_MODULE_STUFF,
+   NULL,                 /* create per-dir config */
+   NULL,                 /* merge per-dir config */
+   so_sconf_create,      /* server config */
+   NULL,                 /* merge server config */
+   so_cmds,              /* command apr_table_t */
+   register_hooks        /* register hooks */
+};