Fix bug #64865: Use CONTEXT_DOCUMENT_ROOT for scanning dir tree

If CONTEXT_DOCUMENT_ROOT is set use that rather than DOCUMENT_ROOT to
scan up the dir tree looking for .user.ini files.

Closes GH-5051.

Author: wbender

NEWS

@@ -25,6 +25,10 @@ PHP                                                                        NEWS
   . Add property DOMXPath::$registerNodeNamespaces and constructor argument
     that allow global flag to configure query() or evaluate() calls.
 
+- FPM:
+  . Fixed bug #64865 (Search for .user.ini files from script dir up to
+    CONTEXT_DOCUMENT_ROOT). (Will Bender)
+
 - GD:
   . Fixed bug #55005 (imagepolygon num_points requirement). (cmb)
   . Replaced gd resources with objects. (Mark Randall)

UPGRADING

@@ -371,6 +371,10 @@ PHP 8.0 UPGRADE NOTES
 3. Changes in SAPI modules
 ========================================
 
+- CGI and FPM will now use CONTEXT_DOCUMENT_ROOT to scan for .user.ini files,
+  if it is defined. Otherwise, DOCUMENT_ROOT will be used as before. This
+  improves support for Apache mod_userdir and mod_alias.
+
 ========================================
 4. Deprecated Functionality
 ========================================

sapi/cgi/cgi_main.c

@@ -913,9 +913,12 @@ static int sapi_cgi_activate(void)
 			if (fcgi_is_fastcgi()) {
 				fcgi_request *request = (fcgi_request*) SG(server_context);
 
-				doc_root = FCGI_GETENV(request, "DOCUMENT_ROOT");
+				/* Prefer CONTEXT_DOCUMENT_ROOT if set */
+				doc_root = FCGI_GETENV(request, "CONTEXT_DOCUMENT_ROOT");
+				doc_root = doc_root ? doc_root : FCGI_GETENV(request, "DOCUMENT_ROOT");
 			} else {
-				doc_root = getenv("DOCUMENT_ROOT");
+				doc_root = getenv("CONTEXT_DOCUMENT_ROOT");
+				doc_root = doc_root ? doc_root : getenv("DOCUMENT_ROOT");
 			}
 			/* DOCUMENT_ROOT should also be defined at this stage..but better check it anyway */
 			if (doc_root) {

sapi/fpm/fpm/fpm_main.c

@@ -733,7 +733,10 @@ static int sapi_cgi_activate(void) /* {{{ */
 
 		/* Load and activate user ini files in path starting from DOCUMENT_ROOT */
 		if (PG(user_ini_filename) && *PG(user_ini_filename)) {
-			doc_root = FCGI_GETENV(request, "DOCUMENT_ROOT");
+			/* Prefer CONTEXT_DOCUMENT_ROOT if set */
+			doc_root = FCGI_GETENV(request, "CONTEXT_DOCUMENT_ROOT");
+			doc_root = doc_root ? doc_root : FCGI_GETENV(request, "DOCUMENT_ROOT");
+
 			/* DOCUMENT_ROOT should also be defined at this stage..but better check it anyway */
 			if (doc_root) {
 				doc_root_len = strlen(doc_root);