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Commit 283d7559 authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

tracehook: syscall 



This adds standard tracehook.h inlines for arch code to call when
TIF_SYSCALL_TRACE has been set.  This replaces having each arch implement
the ptrace guts for its syscall tracing support.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 445a91d2

include/linux/tracehook.h

+70 −0
Original line number Original line Diff line number Diff line
@@ -66,6 +66,76 @@ static inline int tracehook_expect_breakpoints(struct task_struct *task) 
	return (task_ptrace(task) & PT_PTRACED) != 0;

	return (task_ptrace(task) & PT_PTRACED) != 0;

}

}





/*

 * ptrace report for syscall entry and exit looks identical.

 */

static inline void ptrace_report_syscall(struct pt_regs *regs)

{

	int ptrace = task_ptrace(current);



	if (!(ptrace & PT_PTRACED))

		return;



	ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));



	/*

	 * this isn't the same as continuing with a signal, but it will do

	 * for normal use.  strace only continues with a signal if the

	 * stopping signal is not SIGTRAP.  -brl

	 */

	if (current->exit_code) {

		send_sig(current->exit_code, current, 1);

		current->exit_code = 0;

	}

}



/**

 * tracehook_report_syscall_entry - task is about to attempt a system call

 * @regs:		user register state of current task

 *

 * This will be called if %TIF_SYSCALL_TRACE has been set, when the

 * current task has just entered the kernel for a system call.

 * Full user register state is available here.  Changing the values

 * in @regs can affect the system call number and arguments to be tried.

 * It is safe to block here, preventing the system call from beginning.

 *

 * Returns zero normally, or nonzero if the calling arch code should abort

 * the system call.  That must prevent normal entry so no system call is

 * made.  If @task ever returns to user mode after this, its register state

 * is unspecified, but should be something harmless like an %ENOSYS error

 * return.

 *

 * Called without locks, just after entering kernel mode.

 */

static inline __must_check int tracehook_report_syscall_entry(

	struct pt_regs *regs)

{

	ptrace_report_syscall(regs);

	return 0;

}



/**

 * tracehook_report_syscall_exit - task has just finished a system call

 * @regs:		user register state of current task

 * @step:		nonzero if simulating single-step or block-step

 *

 * This will be called if %TIF_SYSCALL_TRACE has been set, when the

 * current task has just finished an attempted system call.  Full

 * user register state is available here.  It is safe to block here,

 * preventing signals from being processed.

 *

 * If @step is nonzero, this report is also in lieu of the normal

 * trap that would follow the system call instruction because

 * user_enable_block_step() or user_enable_single_step() was used.

 * In this case, %TIF_SYSCALL_TRACE might not be set.

 *

 * Called without locks, just before checking for pending signals.

 */

static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)

{

	ptrace_report_syscall(regs);

}



/**

/**

 * tracehook_unsafe_exec - check for exec declared unsafe due to tracing

 * tracehook_unsafe_exec - check for exec declared unsafe due to tracing

 * @task:		current task doing exec

 * @task:		current task doing exec