diff options
Diffstat (limited to 'content/common/child_process_host.h')
-rw-r--r-- | content/common/child_process_host.h | 48 |
1 files changed, 40 insertions, 8 deletions
diff --git a/content/common/child_process_host.h b/content/common/child_process_host.h index 7fd7082..8637c18 100644 --- a/content/common/child_process_host.h +++ b/content/common/child_process_host.h @@ -33,6 +33,42 @@ class Message; class ChildProcessHost : public IPC::Channel::Listener, public IPC::Message::Sender { public: + + // These flags may be passed to GetChildPath in order to alter its behavior, + // causing it to return a child path more suited to a specific task. + enum { + // No special behavior requested. + CHILD_NORMAL = 0, + +#if defined(OS_LINUX) + // Indicates that the child execed after forking may be execced from + // /proc/self/exe rather than using the "real" app path. This prevents + // autoupdate from confusing us if it changes the file out from under us. + // You will generally want to set this on Linux, except when there is an + // override to the command line (for example, we're forking a renderer in + // gdb). In this case, you'd use GetChildPath to get the real executable + // file name, and then prepend the GDB command to the command line. + CHILD_ALLOW_SELF = 1 << 0, +#elif defined(OS_MACOSX) + + // Requests that the child run in a process that does not have the + // PIE (position-independent executable) bit set, effectively disabling + // ASLR. For process types that need to allocate a large contiguous + // region, ASLR may not leave a large enough "hole" for the purpose. This + // option should be used sparingly, and only when absolutely necessary. + // This option is currently incompatible with CHILD_ALLOW_HEAP_EXECUTION. + CHILD_NO_PIE = 1 << 1, + + // Requests that the child run in a process that does not protect the + // heap against execution. Normally, heap pages may be made executable + // with mprotect, so this mode should be used sparingly. It is intended + // for processes that may host plug-ins that expect an executable heap + // without having to call mprotect. This option is currently incompatible + // with CHILD_NO_PIE. + CHILD_ALLOW_HEAP_EXECUTION = 1 << 2, +#endif + }; + virtual ~ChildProcessHost(); // Returns the pathname to be used for a child process. If a subprocess @@ -40,16 +76,12 @@ class ChildProcessHost : public IPC::Channel::Listener, // the default child process pathname will be returned. On most platforms, // this will be the same as the currently-executing process. // - // The argument allow_self is used on Linux to indicate that we allow us to - // fork from /proc/self/exe rather than using the "real" app path. This - // prevents autoupdate from confusing us if it changes the file out from - // under us. You will generally want to set this to true, except when there - // is an override to the command line (for example, we're forking a renderer - // in gdb). In this case, you'd use GetChildPath to get the real executable - // file name, and then prepend the GDB command to the command line. + // The |flags| argument accepts one or more flags such as CHILD_ALLOW_SELF + // and CHILD_ALLOW_HEAP_EXECUTION as defined above. Pass only CHILD_NORMAL + // if none of these special behaviors are required. // // On failure, returns an empty FilePath. - static FilePath GetChildPath(bool allow_self); + static FilePath GetChildPath(int flags); #if defined(OS_WIN) // See comments in the cc file. This is a common hack needed for a process |