Merge r1909137, r1911067 from trunk:

mod_alias: When an alias is declared inside a Location, make sure
the balance of the URL is preserved to match the alias declared
outside a location. Fixes an error where all requests are mapped
to the root of the location.


mod_alias: Add AliasPreservePath directive to map the full
path after the alias in a location.

Submitted by: minfrin
Reviewed by: minfrin, rpluem, covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1913009 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -149,6 +149,9 @@ Changes with Apache 2.4.58
   *) mod_dav: Add DavBasePath directive to configure the repository root
      path.  PR 35077.  [Joe Orton]
 
+  *) mod_alias: Add AliasPreservePath directive to map the full
+     path after the alias in a location. [Graham Leggett]
+
   *) mod_alias: Add RedirectRelative to allow relative redirect targets to be
      issued as-is. [Eric Covener, Graham Leggett]
 

STATUS

@@ -152,15 +152,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
 
-  *) mod_alias: Add AliasPreservePath directive to map the full path after the
-     alias in a location. Requires r1861542 / r1861569 above.
-     Trunk version of patch:
-        https://svn.apache.org/r1909137
-        https://svn.apache.org/r1911067
-     Backport version for 2.4.x of patch:
-        https://svn.apache.org/repos/asf/httpd/httpd/patches/2.4.x/alias-preserve-path3.diff
-     +1: minfrin, rpluem, covener
-
   *) mod_ssl: Silence info log message "SSL Library Error: error:0A000126:
      SSL routines::unexpected eof while reading" when using
      OpenSSL 3 by setting SSL_OP_IGNORE_UNEXPECTED_EOF if

docs/manual/mod/mod_alias.xml

@@ -194,6 +194,24 @@ Alias "/image" "/ftp/pub/image"
 </LocationMatch>
     </highlight>
 
+    <p>Note that when the <directive>AliasPreservePath</directive>
+    directive is on, the full path is mapped to the destination. When
+    the directive is off, all URLs are mapped to the single target
+    URL.</p>
+
+    <highlight language="config">
+# /files/foo and /files/bar mapped to /ftp/pub/files/foo and /ftp/pub/files/bar
+&lt;Location "/files"&gt;
+    AliasPreservePath on
+    Alias "/ftp/pub/files"
+&lt;/Location&gt;
+# /errors/foo and /errors/bar mapped to /var/www/errors.html
+&lt;Location "/errors"&gt;
+    AliasPreservePath off
+    Alias "/var/www/errors.html"
+&lt;/Location&gt;
+    </highlight>
+
 </usage>
 </directivesynopsis>
 
@@ -638,5 +656,30 @@ ScriptAliasMatch "(?i)^/cgi-bin(.*)" "/usr/local/apache/cgi-bin$1"
 </usage>
 </directivesynopsis>
 
+<directivesynopsis>
+<name>AliasPreservePath</name>
+<description>Map the full path after the alias in a location.</description>
+<syntax>AliasPreservePath OFF|ON</syntax>
+<default>AliasPreservePath OFF</default>
+<contextlist><context>server config</context><context>virtual host</context>
+<context>directory</context>
+</contextlist>
+<compatibility>2.5.1 and later</compatibility>
+
+<usage>
+    <p>When using the two parameter version of the
+    <directive>Alias</directive> directive, the full path after the alias
+    is preserved. When using the one parameter version of the
+    <directive>Alias</directive> directive inside a
+    <directive>Location</directive> directive, the full path is dropped,
+    and all URLs are mapped to the target expression.</p>
+
+    <p>To make the one parameter version of the
+    <directive>Alias</directive> directive preserve paths in the same way
+    that the two parameter version of the <directive>Alias</directive>
+    directive, enable this setting.</p>
+
+</usage>
+</directivesynopsis>
 
 </modulesynopsis>

modules/mappers/mod_alias.c

@@ -41,6 +41,8 @@
 #define ALIAS_FLAG_OFF 0
 #define ALIAS_FLAG_ON  1
 
+#define ALIAS_PRESERVE_PATH_DEFAULT 0
+
 typedef struct {
     const char *real;
     const char *fake;
@@ -59,10 +61,12 @@ typedef struct {
     unsigned int redirect_set:1;
     apr_array_header_t *redirects;
     const ap_expr_info_t *alias;
+    const char *alias_fake;
     char *handler;
     const ap_expr_info_t *redirect;
     int redirect_status;                /* 301, 302, 303, 410, etc */
     int allow_relative;                 /* skip ap_construct_url() */
+    int alias_preserve_path;            /* map full path */
 } alias_dir_conf;
 
 module AP_MODULE_DECLARE_DATA alias_module;
@@ -86,6 +90,7 @@ static void *create_alias_dir_config(apr_pool_t *p, char *d)
     (alias_dir_conf *) apr_pcalloc(p, sizeof(alias_dir_conf));
     a->redirects = apr_array_make(p, 2, sizeof(alias_entry));
     a->allow_relative = ALIAS_FLAG_DEFAULT;
+    a->alias_preserve_path = ALIAS_FLAG_DEFAULT;
     return a;
 }
 
@@ -111,6 +116,7 @@ static void *merge_alias_dir_config(apr_pool_t *p, void *basev, void *overridesv
     a->redirects = apr_array_append(p, overrides->redirects, base->redirects);
 
     a->alias = (overrides->alias_set == 0) ? base->alias : overrides->alias;
+    a->alias_fake = (overrides->alias_set == 0) ? base->alias_fake : overrides->alias_fake;
     a->handler = (overrides->alias_set == 0) ? base->handler : overrides->handler;
     a->alias_set = overrides->alias_set || base->alias_set;
 
@@ -120,6 +126,10 @@ static void *merge_alias_dir_config(apr_pool_t *p, void *basev, void *overridesv
     a->allow_relative = (overrides->allow_relative != ALIAS_FLAG_DEFAULT)
                                   ? overrides->allow_relative 
                                   : base->allow_relative;
+    a->alias_preserve_path = (overrides->alias_preserve_path != ALIAS_FLAG_DEFAULT)
+                                  ? overrides->alias_preserve_path
+                                  : base->alias_preserve_path;
+
     return a;
 }
 
@@ -218,6 +228,7 @@ static const char *add_alias(cmd_parms *cmd, void *dummy, const char *fake,
                     NULL);
         }
 
+        dirconf->alias_fake = cmd->path;
         dirconf->handler = cmd->info;
         dirconf->alias_set = 1;
 
@@ -436,6 +447,17 @@ static char *try_alias(request_rec *r)
             return PREGSUB_ERROR;
         }
 
+        if (dirconf->alias_fake && dirconf->alias_preserve_path == ALIAS_FLAG_ON) {
+            int l;
+
+            l = alias_matches(r->uri, dirconf->alias_fake);
+
+            if (l > 0) {
+                ap_set_context_info(r, dirconf->alias_fake, found);
+                found = apr_pstrcat(r->pool, found, r->uri + l, NULL);
+            }
+        }
+
         if (dirconf->handler) { /* Set handler, and leave a note for mod_cgi */
             r->handler = dirconf->handler;
             apr_table_setn(r->notes, "alias-forced-type", r->handler);
@@ -715,6 +737,9 @@ static const command_rec alias_cmds[] =
     AP_INIT_FLAG("RedirectRelative", ap_set_flag_slot,
                   (void*)APR_OFFSETOF(alias_dir_conf, allow_relative), OR_FILEINFO,
                   "Set to ON to allow relative redirect targets to be issued as-is"),
+    AP_INIT_FLAG("AliasPreservePath", ap_set_flag_slot,
+                  (void*)APR_OFFSETOF(alias_dir_conf, alias_preserve_path), OR_FILEINFO,
+                  "Set to ON to map the full path after the fakename to the realname."),
 
     {NULL}
 };