1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CONTENT_PULIC_COMMON_CHILD_PROCESS_HOST_H_ 6 #define CONTENT_PULIC_COMMON_CHILD_PROCESS_HOST_H_ 7 8 #include "build/build_config.h" 9 #include "content/common/content_export.h" 10 #include "ipc/ipc_channel_proxy.h" 11 12 namespace base { 13 class FilePath; 14 } 15 16 namespace content { 17 18 class ChildProcessHostDelegate; 19 20 // This represents a non-browser process. This can include traditional child 21 // processes like plugins, or an embedder could even use this for long lived 22 // processes that run independent of the browser process. 23 class CONTENT_EXPORT ChildProcessHost : public IPC::Sender { 24 public: 25 virtual ~ChildProcessHost() {} 26 27 // Used to create a child process host. The delegate must outlive this object. 28 static ChildProcessHost* Create( 29 ChildProcessHostDelegate* delegate); 30 31 // These flags may be passed to GetChildPath in order to alter its behavior, 32 // causing it to return a child path more suited to a specific task. 33 enum { 34 // No special behavior requested. 35 CHILD_NORMAL = 0, 36 37 #if defined(OS_LINUX) 38 // Indicates that the child execed after forking may be execced from 39 // /proc/self/exe rather than using the "real" app path. This prevents 40 // autoupdate from confusing us if it changes the file out from under us. 41 // You will generally want to set this on Linux, except when there is an 42 // override to the command line (for example, we're forking a renderer in 43 // gdb). In this case, you'd use GetChildPath to get the real executable 44 // file name, and then prepend the GDB command to the command line. 45 CHILD_ALLOW_SELF = 1 << 0, 46 #elif defined(OS_MACOSX) 47 48 // Requests that the child run in a process that does not have the 49 // PIE (position-independent executable) bit set, effectively disabling 50 // ASLR. For process types that need to allocate a large contiguous 51 // region, ASLR may not leave a large enough "hole" for the purpose. This 52 // option should be used sparingly, and only when absolutely necessary. 53 // This option is currently incompatible with CHILD_ALLOW_HEAP_EXECUTION. 54 CHILD_NO_PIE = 1 << 1, 55 56 // Requests that the child run in a process that does not protect the 57 // heap against execution. Normally, heap pages may be made executable 58 // with mprotect, so this mode should be used sparingly. It is intended 59 // for processes that may host plug-ins that expect an executable heap 60 // without having to call mprotect. This option is currently incompatible 61 // with CHILD_NO_PIE. 62 CHILD_ALLOW_HEAP_EXECUTION = 1 << 2, 63 #endif 64 }; 65 66 // Returns the pathname to be used for a child process. If a subprocess 67 // pathname was specified on the command line, that will be used. Otherwise, 68 // the default child process pathname will be returned. On most platforms, 69 // this will be the same as the currently-executing process. 70 // 71 // The |flags| argument accepts one or more flags such as CHILD_ALLOW_SELF 72 // and CHILD_ALLOW_HEAP_EXECUTION as defined above. Pass only CHILD_NORMAL 73 // if none of these special behaviors are required. 74 // 75 // On failure, returns an empty FilePath. 76 static base::FilePath GetChildPath(int flags); 77 78 // Send the shutdown message to the child process. 79 // Does not check with the delegate's CanShutdown. 80 virtual void ForceShutdown() = 0; 81 82 // Creates the IPC channel. Returns the channel id if it succeeded, an 83 // empty string otherwise 84 virtual std::string CreateChannel() = 0; 85 86 // Returns true iff the IPC channel is currently being opened; 87 virtual bool IsChannelOpening() = 0; 88 89 // Adds an IPC message filter. A reference will be kept to the filter. 90 virtual void AddFilter(IPC::ChannelProxy::MessageFilter* filter) = 0; 91 92 #if defined(OS_POSIX) 93 // See IPC::Channel::TakeClientFileDescriptor. 94 virtual int TakeClientFileDescriptor() = 0; 95 #endif 96 }; 97 98 }; // namespace content 99 100 #endif // CONTENT_PULIC_COMMON_CHILD_PROCESS_HOST_H_ 101
