From 86b6c1f301faf085de5a3f9ce16b8de6e69c729b Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 23 Mar 2012 15:02:41 -0700 Subject: 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 Acked-by: Tejun Heo Reviewed-by: Oleg Nesterov Cc: Pedro Alves Cc: Jan Kratochvil Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/ptrace.c | 31 ++++++++----------------------- 1 file changed, 8 insertions(+), 23 deletions(-) (limited to 'kernel') diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 273f56ea39d2..9acd07a6f5bb 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -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; } -- cgit v1.2.3