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authorTejun Heo <tj@kernel.org>2011-06-17 16:50:35 +0200
committerOleg Nesterov <oleg@redhat.com>2011-06-22 19:26:28 +0200
commit643ad8388e189dfd14ef76972cf7dc394b3cbebd (patch)
tree82d4787ddc09cf5a6fc9fc1345839973ab7763f5 /include/linux/ptrace.h
parentd21142ece414ce1088cfcae760689aa60d6fee80 (diff)
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>
Diffstat (limited to 'include/linux/ptrace.h')
-rw-r--r--include/linux/ptrace.h46
1 files changed, 32 insertions, 14 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 3ff20b322598..18feac6f441e 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -90,12 +90,17 @@
#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_TRACE_FORK 0x00000010
-#define PT_TRACE_VFORK 0x00000020
-#define PT_TRACE_CLONE 0x00000040
-#define PT_TRACE_EXEC 0x00000080
-#define PT_TRACE_VFORK_DONE 0x00000100
-#define PT_TRACE_EXIT 0x00000200
+
+/* 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_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)
+#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
+#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
@@ -146,25 +151,38 @@ int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
unsigned long data);
/**
+ * ptrace_event_enabled - test whether a ptrace event is enabled
+ * @task: ptracee of interest
+ * @event: %PTRACE_EVENT_* to test
+ *
+ * Test whether @event is enabled for ptracee @task.
+ *
+ * Returns %true if @event is enabled, %false otherwise.
+ */
+static inline bool ptrace_event_enabled(struct task_struct *task, int event)
+{
+ return task->ptrace & PT_EVENT_FLAG(event);
+}
+
+/**
* ptrace_event - possibly stop for a ptrace event notification
- * @mask: %PT_* bit to check in @current->ptrace
- * @event: %PTRACE_EVENT_* value to report if @mask is set
+ * @event: %PTRACE_EVENT_* value to report
* @message: value for %PTRACE_GETEVENTMSG to return
*
- * This checks the @mask bit to see if ptrace wants stops for this event.
- * If so we stop, reporting @event and @message to the ptrace parent.
+ * Check whether @event is enabled and, if so, report @event and @message
+ * to the ptrace parent.
*
* Returns nonzero if we did a ptrace notification, zero if not.
*
* Called without locks.
*/
-static inline int ptrace_event(int mask, int event, unsigned long message)
+static inline int ptrace_event(int event, unsigned long message)
{
- if (mask && likely(!(current->ptrace & mask)))
- return 0;
+ if (likely(!ptrace_event_enabled(current, event)))
+ return false;
current->ptrace_message = message;
ptrace_notify((event << 8) | SIGTRAP);
- return 1;
+ return true;
}
/**