Commit 86b6c1f3 authored by Denys Vlasenko's avatar Denys Vlasenko Committed by Linus Torvalds
Browse files

ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code 



Exchange PT_TRACESYSGOOD and PT_PTRACE_CAP bit positions, which makes
PT_option bits contiguous and therefore makes code in
ptrace_setoptions() much simpler.

Every PTRACE_O_TRACEevent is defined to (1 << PTRACE_EVENT_event)
instead of using explicit numeric constants, to ensure we don't mess up
relationship between bit positions and event ids.

PT_EVENT_FLAG_SHIFT was not particularly useful, PT_OPT_FLAG_SHIFT with
value of PT_EVENT_FLAG_SHIFT-1 is easier to use.

PT_TRACE_MASK constant is nuked, the only its use is replaced by
(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT).

Signed-off-by: default avatarDenys Vlasenko <vda.linux@googlemail.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8c5cf9e5

include/linux/ptrace.h

+15 −18
Original line number Diff line number Diff line
@@ -54,17 +54,6 @@ 
/* flags in @data for PTRACE_SEIZE */

#define PTRACE_SEIZE_DEVEL	0x80000000 /* temp flag for development */



/* options set using PTRACE_SETOPTIONS */

#define PTRACE_O_TRACESYSGOOD	0x00000001

#define PTRACE_O_TRACEFORK	0x00000002

#define PTRACE_O_TRACEVFORK	0x00000004

#define PTRACE_O_TRACECLONE	0x00000008

#define PTRACE_O_TRACEEXEC	0x00000010

#define PTRACE_O_TRACEVFORKDONE	0x00000020

#define PTRACE_O_TRACEEXIT	0x00000040



#define PTRACE_O_MASK		0x0000007f



/* Wait extended result codes for the above trace options.  */

#define PTRACE_EVENT_FORK	1

#define PTRACE_EVENT_VFORK	2
@@ -74,6 +63,17 @@ 
#define PTRACE_EVENT_EXIT	6

#define PTRACE_EVENT_STOP	7



/* options set using PTRACE_SETOPTIONS */

#define PTRACE_O_TRACESYSGOOD	1

#define PTRACE_O_TRACEFORK	(1 << PTRACE_EVENT_FORK)

#define PTRACE_O_TRACEVFORK	(1 << PTRACE_EVENT_VFORK)

#define PTRACE_O_TRACECLONE	(1 << PTRACE_EVENT_CLONE)

#define PTRACE_O_TRACEEXEC	(1 << PTRACE_EVENT_EXEC)

#define PTRACE_O_TRACEVFORKDONE	(1 << PTRACE_EVENT_VFORK_DONE)

#define PTRACE_O_TRACEEXIT	(1 << PTRACE_EVENT_EXIT)



#define PTRACE_O_MASK		0x0000007f



#include <asm/ptrace.h>



#ifdef __KERNEL__
@@ -88,13 +88,12 @@ 
#define PT_SEIZED	0x00010000	/* SEIZE used, enable new behavior */

#define PT_PTRACED	0x00000001

#define PT_DTRACE	0x00000002	/* delayed trace (used on m68k, i386) */

#define PT_TRACESYSGOOD	0x00000004

#define PT_PTRACE_CAP	0x00000008	/* ptracer can follow suid-exec */

#define PT_PTRACE_CAP	0x00000004	/* ptracer can follow suid-exec */



#define PT_OPT_FLAG_SHIFT	3

/* PT_TRACE_* event enable flags */

#define PT_EVENT_FLAG_SHIFT	4

#define PT_EVENT_FLAG(event)	(1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))



#define PT_EVENT_FLAG(event)	(1 << (PT_OPT_FLAG_SHIFT + (event)))

#define PT_TRACESYSGOOD		PT_EVENT_FLAG(0)

#define PT_TRACE_FORK		PT_EVENT_FLAG(PTRACE_EVENT_FORK)

#define PT_TRACE_VFORK		PT_EVENT_FLAG(PTRACE_EVENT_VFORK)

#define PT_TRACE_CLONE		PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
@@ -102,8 +101,6 @@ 
#define PT_TRACE_VFORK_DONE	PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)

#define PT_TRACE_EXIT		PT_EVENT_FLAG(PTRACE_EVENT_EXIT)



#define PT_TRACE_MASK	0x000003f4



/* single stepping state bits (used on ARM and PA-RISC) */

#define PT_SINGLESTEP_BIT	31

#define PT_SINGLESTEP		(1<<PT_SINGLESTEP_BIT)

kernel/ptrace.c

+8 −23
Original line number Diff line number Diff line
@@ -262,7 +262,7 @@ static int ptrace_attach(struct task_struct *task, long request, 


	/*

	 * Protect exec's credential calculations against our interference;

	 * interference; SUID, SGID and LSM creds get determined differently

	 * SUID, SGID and LSM creds get determined differently

	 * under ptrace.

	 */

	retval = -ERESTARTNOINTR;
@@ -528,31 +528,16 @@ int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long ds 


static int ptrace_setoptions(struct task_struct *child, unsigned long data)

{

	unsigned flags;



	if (data & ~(unsigned long)PTRACE_O_MASK)

		return -EINVAL;



	child->ptrace &= ~PT_TRACE_MASK;



	if (data & PTRACE_O_TRACESYSGOOD)

		child->ptrace |= PT_TRACESYSGOOD;



	if (data & PTRACE_O_TRACEFORK)

		child->ptrace |= PT_TRACE_FORK;



	if (data & PTRACE_O_TRACEVFORK)

		child->ptrace |= PT_TRACE_VFORK;



	if (data & PTRACE_O_TRACECLONE)

		child->ptrace |= PT_TRACE_CLONE;



	if (data & PTRACE_O_TRACEEXEC)

		child->ptrace |= PT_TRACE_EXEC;



	if (data & PTRACE_O_TRACEVFORKDONE)

		child->ptrace |= PT_TRACE_VFORK_DONE;



	if (data & PTRACE_O_TRACEEXIT)

		child->ptrace |= PT_TRACE_EXIT;

	/* Avoid intermediate state when all opts are cleared */

	flags = child->ptrace;

	flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);

	flags |= (data << PT_OPT_FLAG_SHIFT);

	child->ptrace = flags;



	return 0;

}

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