Check that 'dl' function is available and usable before trying to call it with error suppression; if it's disabled or unavailable we end up with mysterious failures during installation or loading of libraries.

Fixed for StatusNet installer as well as some external libraries that should be fixed upstream if they haven't already been:
* PEAR
* Auth/OpenID
* Auth/Yadis

4 files changed, 15 insertions, 8 deletions

diff --git a/extlib/Auth/OpenID/BigMath.php b/extlib/Auth/OpenID/BigMath.php
index 45104947d..b5fc627a0 100644
--- a/extlib/Auth/OpenID/BigMath.php
+++ b/extlib/Auth/OpenID/BigMath.php
@@ -376,7 +376,7 @@ function Auth_OpenID_detectMathLibrary($exts)
         // Try to load dynamic modules.
         if (!$loaded) {
             foreach ($extension['modules'] as $module) {
-                if (@dl($module . "." . PHP_SHLIB_SUFFIX)) {
+                if (function_exists('dl') && ini_get('enable_dl') && !ini_get('safe_mode') && @dl($module . "." . PHP_SHLIB_SUFFIX)) {
                     $loaded = true;
                     break;
                 }
diff --git a/extlib/Auth/Yadis/XML.php b/extlib/Auth/Yadis/XML.php
index 4854f12bb..7232d6cbd 100644
--- a/extlib/Auth/Yadis/XML.php
+++ b/extlib/Auth/Yadis/XML.php
@@ -349,7 +349,7 @@ function &Auth_Yadis_getXMLParser()
     foreach ($extensions as $name => $params) {
         if (!extension_loaded($name)) {
             foreach ($params['libname'] as $libname) {
-                if (@dl($libname)) {
+                if (function_exists('dl') && ini_get('enable_dl') && !ini_get('safe_mode') && @dl($libname)) {
                     $classname = $params['classname'];
                 }
             }
diff --git a/extlib/PEAR.php b/extlib/PEAR.php
index 4c24c6006..fcefa964a 100644
--- a/extlib/PEAR.php
+++ b/extlib/PEAR.php
@@ -746,7 +746,7 @@ class PEAR
     {
         if (!extension_loaded($ext)) {
             // if either returns true dl() will produce a FATAL error, stop that
-            if ((ini_get('enable_dl') != 1) || (ini_get('safe_mode') == 1)) {
+            if ((ini_get('enable_dl') != 1) || (ini_get('safe_mode') == 1) || !function_exists('dl')) {
                 return false;
             }
             if (OS_WINDOWS) {
diff --git a/install.php b/install.php
index c49043e5c..39984aa08 100644
--- a/install.php
+++ b/install.php
@@ -267,12 +267,19 @@ function checkPrereqs()
 
 function checkExtension($name)
 {
-    if (!extension_loaded($name)) {
-        if (!@dl($name.'.so')) {
-            return false;
-        }
+    if (extension_loaded($name)) {
+        return true;
+    } elseif (function_exists('dl') && ini_get('enable_dl') && !ini_get('safe_mode')) {
+    	// dl will throw a fatal error if it's disabled or we're in safe mode.
+    	// More fun, it may not even exist under some SAPIs in 5.3.0 or later...
+    	$soname = $name . '.' . PHP_SHLIB_SUFFIX;
+    	if (PHP_SHLIB_SUFFIX == 'dll') {
+    		$soname = "php_" . $soname;
+    	}
+    	return @dl($soname);
+    } else {
+        return false;
     }
-    return true;
 }
 
 function showLibs()