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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: Denys Vlasenko <vda.linux@googlemail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Denys Vlasenko 2012-03-23 15:02:41 -07:00 committed by Linus Torvalds
parent 8c5cf9e5c5
commit 86b6c1f301
2 changed files with 23 additions and 41 deletions
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33
include/linux/ptrace.h
View File

@ -54,17 +54,6 @@
/* flags in @data for PTRACE_SEIZE */ /* flags in @data for PTRACE_SEIZE */
#define PTRACE_SEIZE_DEVEL 0x80000000 /* temp flag for development */ #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. */ /* Wait extended result codes for the above trace options. */
#define PTRACE_EVENT_FORK 1 #define PTRACE_EVENT_FORK 1
#define PTRACE_EVENT_VFORK 2 #define PTRACE_EVENT_VFORK 2
@ -74,6 +63,17 @@
#define PTRACE_EVENT_EXIT 6 #define PTRACE_EVENT_EXIT 6
#define PTRACE_EVENT_STOP 7 #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> #include <asm/ptrace.h>
#ifdef __KERNEL__ #ifdef __KERNEL__
@ -88,13 +88,12 @@
#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */ #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
#define PT_PTRACED 0x00000001 #define PT_PTRACED 0x00000001
#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */ #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
#define PT_TRACESYSGOOD 0x00000004 #define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */
#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */
#define PT_OPT_FLAG_SHIFT 3
/* PT_TRACE_* event enable flags */ /* PT_TRACE_* event enable flags */
#define PT_EVENT_FLAG_SHIFT 4 #define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
#define PT_EVENT_FLAG(event) (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1)) #define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK) #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK) #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE) #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_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) #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) */ /* single stepping state bits (used on ARM and PA-RISC) */
#define PT_SINGLESTEP_BIT 31 #define PT_SINGLESTEP_BIT 31
#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT) #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)

31
kernel/ptrace.c
View File

@ -262,7 +262,7 @@ static int ptrace_attach(struct task_struct *task, long request,
/* /*
* Protect exec's credential calculations against our interference; * 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. * under ptrace.
*/ */
retval = -ERESTARTNOINTR; 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) static int ptrace_setoptions(struct task_struct *child, unsigned long data)
{ {
unsigned flags;
if (data & ~(unsigned long)PTRACE_O_MASK) if (data & ~(unsigned long)PTRACE_O_MASK)
return -EINVAL; return -EINVAL;
child->ptrace &= ~PT_TRACE_MASK; /* Avoid intermediate state when all opts are cleared */
flags = child->ptrace;
if (data & PTRACE_O_TRACESYSGOOD) flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
child->ptrace |= PT_TRACESYSGOOD; flags |= (data << PT_OPT_FLAG_SHIFT);
child->ptrace = flags;
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;
return 0; return 0;
} }