From 643ad8388e189dfd14ef76972cf7dc394b3cbebd Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 17 Jun 2011 16:50:35 +0200 Subject: 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 Signed-off-by: Oleg Nesterov --- include/linux/ptrace.h | 46 ++++++++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 14 deletions(-) (limited to 'include/linux/ptrace.h') 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 @@ -145,26 +150,39 @@ int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, 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; } /** -- cgit v1.2.3