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ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code

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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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31
kernel/ptrace.c
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@ -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;
}