fix syscall tls recursion (ebc23cb9) · Commits · hpc / gekkofs

src/client/intercept.cpp

+48 −25

Original line number	Original line	Diff line number	Diff line
	@@ -36,7 +36,7 @@

	SPDX-License-Identifier: LGPL-3.0-or-later		SPDX-License-Identifier: LGPL-3.0-or-later
	*/		*/
			#include <pthread.h>
	#include <client/intercept.hpp>		#include <client/intercept.hpp>
	#include <client/preload.hpp>		#include <client/preload.hpp>
	#include <client/hooks.hpp>		#include <client/hooks.hpp>
	@@ -74,7 +74,13 @@ void (*intercept_hook_point_post_kernel)(long syscall_number, long arg0,
	#endif		#endif
	namespace {		namespace {

	thread_local bool reentrance_guard_flag;		static pthread_key_t reentrance_guard_key;
			static pthread_once_t key_once_control = PTHREAD_ONCE_INIT;
			static void make_key() {
			// This function will be called exactly once per process.
			pthread_key_create(&reentrance_guard_key, NULL);
			}

	thread_local gkfs::syscall::info saved_syscall_info;		thread_local gkfs::syscall::info saved_syscall_info;

	constexpr void		constexpr void
	@@ -533,7 +539,8 @@ hook(long syscall_number, long arg0, long arg1, long arg2, long arg3, long arg4,

	case SYS_execve:		case SYS_execve:
	// If we do not set this to false, we are in trouble with vforks		// If we do not set this to false, we are in trouble with vforks
	reentrance_guard_flag = false;		pthread_once(&key_once_control, make_key);
			pthread_setspecific(reentrance_guard_key, NULL);
	*result = syscall_no_intercept_wrapper(		*result = syscall_no_intercept_wrapper(
	syscall_number, reinterpret_cast<const char*>(arg0),		syscall_number, reinterpret_cast<const char*>(arg0),
	reinterpret_cast<const char* const*>(arg1),		reinterpret_cast<const char* const*>(arg1),
	@@ -543,7 +550,8 @@ hook(long syscall_number, long arg0, long arg1, long arg2, long arg3, long arg4,
	#ifdef SYS_execveat		#ifdef SYS_execveat
	case SYS_execveat:		case SYS_execveat:
	// If we do not set this to false, we are in trouble with vforks		// If we do not set this to false, we are in trouble with vforks
	reentrance_guard_flag = false;		pthread_once(&key_once_control, make_key);
			pthread_setspecific(reentrance_guard_key, NULL);
	*result = syscall_no_intercept_wrapper(		*result = syscall_no_intercept_wrapper(
	syscall_number, arg0, reinterpret_cast<const char*>(arg1),		syscall_number, arg0, reinterpret_cast<const char*>(arg1),
	reinterpret_cast<const char* const*>(arg2),		reinterpret_cast<const char* const*>(arg2),
	@@ -1011,12 +1019,19 @@ socketcall_wrapper(long syscall_number, long& arg0, long& arg1, long& arg2,
	}		}
	#endif		#endif


	void		void
	hook_forwarded_syscall(long syscall_number, long arg0, long arg1, long arg2,		hook_forwarded_syscall(long syscall_number, long arg0, long arg1, long arg2,
	long arg3, long arg4, long arg5, long result) {		long arg3, long arg4, long arg5, long result) {

			pthread_once(&key_once_control, make_key);
			if (pthread_getspecific(reentrance_guard_key) != NULL) {
			return;
			}
			pthread_setspecific(reentrance_guard_key, (void*) 1);


	if(::get_current_syscall_info() == gkfs::syscall::no_info) {		if(::get_current_syscall_info() == gkfs::syscall::no_info) {
			pthread_setspecific(reentrance_guard_key, NULL);
	return;		return;
	}		}

	@@ -1029,6 +1044,8 @@ hook_forwarded_syscall(long syscall_number, long arg0, long arg1, long arg2,
	syscall_number, args, result);		syscall_number, args, result);

	::reset_current_syscall_info();		::reset_current_syscall_info();

			pthread_setspecific(reentrance_guard_key, NULL);
	}		}

	void		void
	@@ -1042,12 +1059,13 @@ hook_clone_at_child(unsigned long flags, void* child_stack, int* ptid,
	static_cast<long>(newtls), 0};		static_cast<long>(newtls), 0};
	#endif		#endif

	reentrance_guard_flag = true;		pthread_once(&key_once_control, make_key);
			pthread_setspecific(reentrance_guard_key, (void*) 1);

	LOG(SYSCALL, ::get_current_syscall_info() \| gkfs::syscall::executed,		LOG(SYSCALL, ::get_current_syscall_info() \| gkfs::syscall::executed,
	SYS_clone, args, 0);		SYS_clone, args, 0);

	reentrance_guard_flag = false;		pthread_setspecific(reentrance_guard_key, NULL);
	}		}

	void		void
	@@ -1061,18 +1079,20 @@ hook_clone_at_parent(unsigned long flags, void* child_stack, int* ptid,
	static_cast<long>(newtls), 0};		static_cast<long>(newtls), 0};
	#endif		#endif

	reentrance_guard_flag = true;		pthread_once(&key_once_control, make_key);
			pthread_setspecific(reentrance_guard_key, (void*) 1);

	LOG(SYSCALL, ::get_current_syscall_info() \| gkfs::syscall::executed,		LOG(SYSCALL, ::get_current_syscall_info() \| gkfs::syscall::executed,
	SYS_clone, args, returned_pid);		SYS_clone, args, returned_pid);

	reentrance_guard_flag = false;		pthread_setspecific(reentrance_guard_key, NULL);
	}		}

	} // namespace		} // namespace

	namespace gkfs::preload {		namespace gkfs::preload {

			// This function is inside 'namespace gkfs::preload'
	int		int
	internal_hook_guard_wrapper(long syscall_number, long arg0, long arg1,		internal_hook_guard_wrapper(long syscall_number, long arg0, long arg1,
	long arg2, long arg3, long arg4, long arg5,		long arg2, long arg3, long arg4, long arg5,
	@@ -1085,7 +1105,8 @@ internal_hook_guard_wrapper(long syscall_number, long arg0, long arg1,
	arg3, arg4, arg5);		arg3, arg4, arg5);
	#endif		#endif

	if(reentrance_guard_flag) {		pthread_once(&key_once_control, make_key);
			if (pthread_getspecific(reentrance_guard_key) != NULL) {
	::save_current_syscall_info(gkfs::syscall::from_internal_code \|		::save_current_syscall_info(gkfs::syscall::from_internal_code \|
	gkfs::syscall::to_kernel \|		gkfs::syscall::to_kernel \|
	gkfs::syscall::not_executed);		gkfs::syscall::not_executed);
	@@ -1094,15 +1115,14 @@ internal_hook_guard_wrapper(long syscall_number, long arg0, long arg1,

	int was_hooked = 0;		int was_hooked = 0;

	reentrance_guard_flag = true;		pthread_setspecific(reentrance_guard_key, (void*) 1);
	was_hooked = hook_internal(syscall_number, arg0, arg1, arg2, arg3, arg4,		was_hooked = hook_internal(syscall_number, arg0, arg1, arg2, arg3, arg4,
	arg5, syscall_return_value);		arg5, syscall_return_value);
	reentrance_guard_flag = false;		pthread_setspecific(reentrance_guard_key, NULL);

	return was_hooked;		return was_hooked;
	}		}


	/*		/*
	* hook_guard_wrapper -- a wrapper which can notice reentrance.		* hook_guard_wrapper -- a wrapper which can notice reentrance.
	*		*
	@@ -1122,6 +1142,17 @@ hook_guard_wrapper(long syscall_number, long arg0, long arg1, long arg2,
	long arg3, long arg4, long arg5,		long arg3, long arg4, long arg5,
	long* syscall_return_value) {		long* syscall_return_value) {

			// --- START OF REVISED FIX for hook_guard_wrapper ---
			pthread_once(&key_once_control, make_key); // Ensure the key is created
			if (pthread_getspecific(reentrance_guard_key) != NULL) {
			// If the guard is set, forward the syscall to the kernel and return.
			return gkfs::syscall::forward_to_kernel;
			}
			// Set the guard to a non-NULL value.
			pthread_setspecific(reentrance_guard_key, (void*) 1);
			// --- END OF REVISED FIX for hook_guard_wrapper ---


	assert(CTX->interception_enabled());		assert(CTX->interception_enabled());

	#ifdef SYS_socketcall		#ifdef SYS_socketcall
	@@ -1132,19 +1163,11 @@ hook_guard_wrapper(long syscall_number, long arg0, long arg1, long arg2,

	int was_hooked = 0;		int was_hooked = 0;

	if(reentrance_guard_flag) {

	was_hooked = hook_internal(syscall_number, arg0, arg1, arg2, arg3, arg4,
	arg5, syscall_return_value);
	return was_hooked;
	}

	reentrance_guard_flag = true;

	was_hooked = ::hook(syscall_number, arg0, arg1, arg2, arg3, arg4, arg5,		was_hooked = ::hook(syscall_number, arg0, arg1, arg2, arg3, arg4, arg5,
	syscall_return_value);		syscall_return_value);

	reentrance_guard_flag = false;		// Unset the guard before returning
			pthread_setspecific(reentrance_guard_key, NULL);

	return was_hooked;		return was_hooked;
	}		}