Make standard input /dev/null when running xdg-settings to set the default browser.

chrome/browser/shell_integration_linux.cc

 // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/shell_integration.h"
 
+#include <fcntl.h>
 #include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
 
 #include <vector>
 
 #include "base/process_util.h"
 
 #if defined(GOOGLE_CHROME_BUILD)
 #define DESKTOP_APP_NAME "google-chrome.desktop"
 #else  // CHROMIUM_BUILD
 #define DESKTOP_APP_NAME "chromium-browser.desktop"
 #endif
 
 // We delegate the difficult of setting the default browser in Linux desktop
 // environments to a new xdg utility, xdg-settings. We'll have to include a copy
 // of it for this to work, obviously, but that's actually the suggested approach
 // for xdg utilities anyway.
 
 bool ShellIntegration::SetAsDefaultBrowser() {
   std::vector<std::string> argv;
   argv.push_back("xdg-settings");
   argv.push_back("set");
   argv.push_back("default-web-browser");
   argv.push_back(DESKTOP_APP_NAME);
 
+  // xdg-settings internally runs xdg-mime, which uses mv to move newly-created
+  // files on top of originals after making changes to them. In the event that
+  // the original files are owned by another user (e.g. root, which can happen
+  // if they are updated within sudo), mv will prompt the user to confirm if
+  // standard input is a terminal (otherwise it just does it). So make sure it's
+  // not, to avoid locking everything up waiting for mv.
+  int devnull = open("/dev/null", O_RDONLY);
+  if (devnull < 0)
+    return false;
+  base::file_handle_mapping_vector no_stdin;
+  no_stdin.push_back(std::make_pair(devnull, STDIN_FILENO));
+
+  base::ProcessHandle handle;
+  if (!base::LaunchApp(argv, no_stdin, false, &handle)) {
+    close(devnull);
+    return false;
+  }
+  close(devnull);
+
   int success_code;
-  base::ProcessHandle handle;
-  base::file_handle_mapping_vector no_files;
-  if (!base::LaunchApp(argv, no_files, false, &handle))
-    return false;
-
   base::WaitForExitCode(handle, &success_code);
   return success_code == EXIT_SUCCESS;
 }
 
 static bool GetDefaultBrowser(std::string* result) {
   std::vector<std::string> argv;
   argv.push_back("xdg-settings");
   argv.push_back("get");
   argv.push_back("default-web-browser");
   return base::GetAppOutput(CommandLine(argv), result);
@@ skipping 14 matching lines @@
     browser.resize(browser.length() - 1);
   return !browser.compare(DESKTOP_APP_NAME);
 }
 
 bool ShellIntegration::IsFirefoxDefaultBrowser() {
   std::string browser;
   // We don't care about the return value here.
   GetDefaultBrowser(&browser);
   return browser.find("irefox") != std::string::npos;
 }