1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/dom/plugins/ipc/interpose/plugin_child_interpose.mm Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,134 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +// Use "dyld interposing" to hook methods imported from other libraries in the
1.10 +// plugin child process. The basic technique is described at
1.11 +// http://books.google.com/books?id=K8vUkpOXhN4C&pg=PA73&lpg=PA73&dq=__interpose&source=bl&ots=OJnnXZYpZC&sig=o7I3lXvoduUi13SrPfOON7o3do4&hl=en&ei=AoehS9brCYGQNrvsmeUM&sa=X&oi=book_result&ct=result&resnum=6&ved=0CBsQ6AEwBQ#v=onepage&q=__interpose&f=false.
1.12 +// The idea of doing it for the plugin child process comes from Chromium code,
1.13 +// particularly from plugin_carbon_interpose_mac.cc
1.14 +// (http://codesearch.google.com/codesearch/p?hl=en#OAMlx_jo-ck/src/chrome/browser/plugin_carbon_interpose_mac.cc&q=nscursor&exact_package=chromium&d=1&l=168)
1.15 +// and from PluginProcessHost::Init() in plugin_process_host.cc
1.16 +// (http://codesearch.google.com/codesearch/p?hl=en#OAMlx_jo-ck/src/content/browser/plugin_process_host.cc&q=nscursor&exact_package=chromium&d=1&l=222).
1.17 +
1.18 +// These hooks are needed to make certain OS calls work from the child process
1.19 +// (a background process) that would normally only work when called in the
1.20 +// parent process (the foreground process). They allow us to serialize
1.21 +// information from the child process to the parent process, so that the same
1.22 +// (or equivalent) calls can be made from the parent process.
1.23 +
1.24 +// This file lives in a seperate module (libplugin_child_interpose.dylib),
1.25 +// which will get loaded by the OS before any other modules when the plugin
1.26 +// child process is launched (from GeckoChildProcessHost::
1.27 +// PerformAsyncLaunchInternal()). For this reason it shouldn't link in other
1.28 +// browser modules when loaded. Instead it should use dlsym() to load
1.29 +// pointers to the methods it wants to call in other modules.
1.30 +
1.31 +#if !defined(__LP64__)
1.32 +
1.33 +#include <dlfcn.h>
1.34 +#import <Carbon/Carbon.h>
1.35 +
1.36 +// The header file QuickdrawAPI.h is missing on OS X 10.7 and up (though the
1.37 +// QuickDraw APIs defined in it are still present) -- so we need to supply the
1.38 +// relevant parts of its contents here. It's likely that Apple will eventually
1.39 +// remove the APIs themselves (probably in OS X 10.8), so we need to make them
1.40 +// weak imports, and test for their presence before using them.
1.41 +#if !defined(__QUICKDRAWAPI__)
1.42 +
1.43 +struct Cursor;
1.44 +extern "C" void SetCursor(const Cursor * crsr) __attribute__((weak_import));
1.45 +
1.46 +#endif /* __QUICKDRAWAPI__ */
1.47 +
1.48 +BOOL (*OnSetThemeCursorPtr) (ThemeCursor) = NULL;
1.49 +BOOL (*OnSetCursorPtr) (const Cursor*) = NULL;
1.50 +BOOL (*OnHideCursorPtr) () = NULL;
1.51 +BOOL (*OnShowCursorPtr) () = NULL;
1.52 +
1.53 +static BOOL loadXULPtrs()
1.54 +{
1.55 + if (!OnSetThemeCursorPtr) {
1.56 + // mac_plugin_interposing_child_OnSetThemeCursor(ThemeCursor cursor) is in
1.57 + // PluginInterposeOSX.mm
1.58 + OnSetThemeCursorPtr = (BOOL(*)(ThemeCursor))
1.59 + dlsym(RTLD_DEFAULT, "mac_plugin_interposing_child_OnSetThemeCursor");
1.60 + }
1.61 + if (!OnSetCursorPtr) {
1.62 + // mac_plugin_interposing_child_OnSetCursor(const Cursor* cursor) is in
1.63 + // PluginInterposeOSX.mm
1.64 + OnSetCursorPtr = (BOOL(*)(const Cursor*))
1.65 + dlsym(RTLD_DEFAULT, "mac_plugin_interposing_child_OnSetCursor");
1.66 + }
1.67 + if (!OnHideCursorPtr) {
1.68 + // mac_plugin_interposing_child_OnHideCursor() is in PluginInterposeOSX.mm
1.69 + OnHideCursorPtr = (BOOL(*)())
1.70 + dlsym(RTLD_DEFAULT, "mac_plugin_interposing_child_OnHideCursor");
1.71 + }
1.72 + if (!OnShowCursorPtr) {
1.73 + // mac_plugin_interposing_child_OnShowCursor() is in PluginInterposeOSX.mm
1.74 + OnShowCursorPtr = (BOOL(*)())
1.75 + dlsym(RTLD_DEFAULT, "mac_plugin_interposing_child_OnShowCursor");
1.76 + }
1.77 + return (OnSetCursorPtr && OnSetThemeCursorPtr && OnHideCursorPtr && OnShowCursorPtr);
1.78 +}
1.79 +
1.80 +static OSStatus MacPluginChildSetThemeCursor(ThemeCursor cursor)
1.81 +{
1.82 + if (loadXULPtrs()) {
1.83 + OnSetThemeCursorPtr(cursor);
1.84 + }
1.85 + return ::SetThemeCursor(cursor);
1.86 +}
1.87 +
1.88 +static void MacPluginChildSetCursor(const Cursor* cursor)
1.89 +{
1.90 + if (::SetCursor) {
1.91 + if (loadXULPtrs()) {
1.92 + OnSetCursorPtr(cursor);
1.93 + }
1.94 + ::SetCursor(cursor);
1.95 + }
1.96 +}
1.97 +
1.98 +static CGError MacPluginChildCGDisplayHideCursor(CGDirectDisplayID display)
1.99 +{
1.100 + if (loadXULPtrs()) {
1.101 + OnHideCursorPtr();
1.102 + }
1.103 + return ::CGDisplayHideCursor(display);
1.104 +}
1.105 +
1.106 +static CGError MacPluginChildCGDisplayShowCursor(CGDirectDisplayID display)
1.107 +{
1.108 + if (loadXULPtrs()) {
1.109 + OnShowCursorPtr();
1.110 + }
1.111 + return ::CGDisplayShowCursor(display);
1.112 +}
1.113 +
1.114 +#pragma mark -
1.115 +
1.116 +struct interpose_substitution {
1.117 + const void* replacement;
1.118 + const void* original;
1.119 +};
1.120 +
1.121 +#define INTERPOSE_FUNCTION(function) \
1.122 + { reinterpret_cast<const void*>(MacPluginChild##function), \
1.123 + reinterpret_cast<const void*>(function) }
1.124 +
1.125 +__attribute__((used)) static const interpose_substitution substitutions[]
1.126 + __attribute__((section("__DATA, __interpose"))) = {
1.127 + INTERPOSE_FUNCTION(SetThemeCursor),
1.128 + INTERPOSE_FUNCTION(CGDisplayHideCursor),
1.129 + INTERPOSE_FUNCTION(CGDisplayShowCursor),
1.130 + // SetCursor() and other QuickDraw APIs will probably be removed in OS X
1.131 + // 10.8. But this will make 'SetCursor' NULL, which will just stop the OS
1.132 + // from interposing it (tested using an INTERPOSE_FUNCTION_BROKEN macro
1.133 + // that just sets the second address of each tuple to NULL).
1.134 + INTERPOSE_FUNCTION(SetCursor),
1.135 +};
1.136 +
1.137 +#endif // !__LP64__
