Stop using "which" to find binaries. Create system::find_binary()

which traverses the $PATH and returns any executable binary of the
appropriate name that it can find.  Fixes #1555.

3 files changed, 50 insertions, 15 deletions

diff --git a/modules/gallery/helpers/graphics.php b/modules/gallery/helpers/graphics.php
index 29527705..18820ed7 100644
--- a/modules/gallery/helpers/graphics.php
+++ b/modules/gallery/helpers/graphics.php
@@ -313,11 +313,6 @@ class graphics_Core {
       $toolkits->graphicsmagick->installed = false;
       $toolkits->graphicsmagick->error = t("GraphicsMagick requires the <b>exec</b> function");
     } else {
-      gallery::set_path_env(
-        array(module::get_var("gallery", "graphics_toolkit_path"),
-              getenv("PATH"),
-              module::get_var("gallery", "extra_binary_paths")));
-
       // ImageMagick & GraphicsMagick
       $magick_kits = array(
           "imagemagick" => array(
@@ -328,7 +323,8 @@ class graphics_Core {
             "version_regex" => "/\S+ (\S+)/"));
       // Loop through the kits
       foreach ($magick_kits as $index => $settings) {
-        $path = exec("which " . $settings["binary"]);
+        $path = system::find_binary(
+          $settings["binary"], module::get_var("gallery", "graphics_toolkit_path"));
         $toolkits->$index->name = $settings["name"];
         if ($path) {
           if (@is_file($path) &&
diff --git a/modules/gallery/helpers/movie.php b/modules/gallery/helpers/movie.php
index 0895c5f4..dd0b437e 100644
--- a/modules/gallery/helpers/movie.php
+++ b/modules/gallery/helpers/movie.php
@@ -83,22 +83,18 @@ class movie_Core {
     }
   }
 
+  /**
+   * Return the path to the ffmpeg binary if one exists and is executable, or null.
+   */
   static function find_ffmpeg() {
     if (!($ffmpeg_path = module::get_var("gallery", "ffmpeg_path")) || !file_exists($ffmpeg_path)) {
-      gallery::set_path_env(
-        array(module::get_var("gallery", "graphics_toolkit_path"),
-              getenv("PATH"),
-              module::get_var("gallery", "extra_binary_paths")));
-      if (function_exists("exec")) {
-        $ffmpeg_path = exec("which ffmpeg");
-      }
-
+      $ffmpeg_path = system::find_binary(
+        "ffmpeg", module::get_var("gallery", "graphics_toolkit_path"));
       module::set_var("gallery", "ffmpeg_path", $ffmpeg_path);
     }
     return $ffmpeg_path;
   }
 
-
   /**
    * Return the width, height, mime_type and extension of the given movie file.
    */
diff --git a/modules/gallery/helpers/system.php b/modules/gallery/helpers/system.php
new file mode 100644
index 00000000..4a6a3c0f
--- /dev/null
+++ b/modules/gallery/helpers/system.php
@@ -0,0 +1,43 @@
+<?php defined("SYSPATH") or die("No direct script access.");
+/**
+ * Gallery - a web based photo album viewer and editor
+ * Copyright (C) 2000-2010 Bharat Mediratta
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+class system_Core {
+  /**
+   * Return the path to an executable version of the named binary, or null.
+   * Traverse the PATH environment variable looking for the given file.  If
+   * the $priority_path variable is set, check that path first.
+   */
+  static function find_binary($binary, $priority_path=null) {
+    $paths = array_merge(
+      explode(":", getenv("PATH")),
+      explode(":", module::get_var("gallery", "extra_binary_paths")));
+    if ($priority_path) {
+      array_unshift($paths, $priority_path);
+    }
+
+    foreach ($paths as $path) {
+      $candidate = "$path/$binary";
+      // @suppress errors below to avoid open_basedir issues
+      if (@file_exists($candidate) && @is_executable($candidate)) {
+        return $candidate;
+      }
+    }
+    return null;
+  }
+}
\ No newline at end of file