ptrace: introduce ptrace_event_enabled() and simplify ptrace_event() and tracehook_prepare_clone()
This patch implements ptrace_event_enabled() which tests whether a
given PTRACE_EVENT_* is enabled and use it to simplify ptrace_event()
and tracehook_prepare_clone().
PT_EVENT_FLAG() macro is added which calculates PT_TRACE_* flag from
PTRACE_EVENT_*. This is used to define PT_TRACE_* flags and by
ptrace_event_enabled() to find the matching flag.
This is used to make ptrace_event() and tracehook_prepare_clone()
simpler.
* ptrace_event() callers were responsible for providing mask to test
whether the event was enabled. This patch implements
ptrace_event_enabled() and make ptrace_event() drop @mask and
determine whether the event is enabled from @event. Note that
@event is constant and this conversion doesn't add runtime overhead.
All conversions except tracehook_report_clone_complete() are
trivial. tracehook_report_clone_complete() used to use 0 for @mask
(always enabled) but now tests whether the specified event is
enabled. This doesn't cause any behavior difference as it's
guaranteed that the event specified by @trace is enabled.
* tracehook_prepare_clone() now only determines which event is
applicable and use ptrace_event_enabled() for enable test.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index a3e8387..7d38571 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -201,7 +201,7 @@
struct linux_binprm *bprm,
struct pt_regs *regs)
{
- if (!ptrace_event(PT_TRACE_EXEC, PTRACE_EVENT_EXEC, 0) &&
+ if (!ptrace_event(PTRACE_EVENT_EXEC, 0) &&
unlikely(current->ptrace & PT_PTRACED))
send_sig(SIGTRAP, current, 0);
}
@@ -218,7 +218,7 @@
*/
static inline void tracehook_report_exit(long *exit_code)
{
- ptrace_event(PT_TRACE_EXIT, PTRACE_EVENT_EXIT, *exit_code);
+ ptrace_event(PTRACE_EVENT_EXIT, *exit_code);
}
/**
@@ -232,19 +232,19 @@
*/
static inline int tracehook_prepare_clone(unsigned clone_flags)
{
+ int event = 0;
+
if (clone_flags & CLONE_UNTRACED)
return 0;
- if (clone_flags & CLONE_VFORK) {
- if (current->ptrace & PT_TRACE_VFORK)
- return PTRACE_EVENT_VFORK;
- } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
- if (current->ptrace & PT_TRACE_CLONE)
- return PTRACE_EVENT_CLONE;
- } else if (current->ptrace & PT_TRACE_FORK)
- return PTRACE_EVENT_FORK;
+ if (clone_flags & CLONE_VFORK)
+ event = PTRACE_EVENT_VFORK;
+ else if ((clone_flags & CSIGNAL) != SIGCHLD)
+ event = PTRACE_EVENT_CLONE;
+ else
+ event = PTRACE_EVENT_FORK;
- return 0;
+ return ptrace_event_enabled(current, event) ? event : 0;
}
/**
@@ -318,7 +318,7 @@
struct task_struct *child)
{
if (unlikely(trace))
- ptrace_event(0, trace, pid);
+ ptrace_event(trace, pid);
}
/**
@@ -336,7 +336,7 @@
static inline void tracehook_report_vfork_done(struct task_struct *child,
pid_t pid)
{
- ptrace_event(PT_TRACE_VFORK_DONE, PTRACE_EVENT_VFORK_DONE, pid);
+ ptrace_event(PTRACE_EVENT_VFORK_DONE, pid);
}
/**