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author | Tejun Heo <tj@kernel.org> | 2011-06-17 16:50:35 +0200 |
---|---|---|
committer | Oleg Nesterov <oleg@redhat.com> | 2011-06-22 19:26:28 +0200 |
commit | 643ad8388e189dfd14ef76972cf7dc394b3cbebd (patch) | |
tree | 82d4787ddc09cf5a6fc9fc1345839973ab7763f5 /include | |
parent | d21142ece414ce1088cfcae760689aa60d6fee80 (diff) | |
download | linux-stable-643ad8388e189dfd14ef76972cf7dc394b3cbebd.tar.gz linux-stable-643ad8388e189dfd14ef76972cf7dc394b3cbebd.tar.bz2 linux-stable-643ad8388e189dfd14ef76972cf7dc394b3cbebd.zip |
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')
-rw-r--r-- | include/linux/ptrace.h | 46 | ||||
-rw-r--r-- | include/linux/tracehook.h | 26 |
2 files changed, 45 insertions, 27 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; } /** diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index a3e838784f43..7d38571b0c05 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -201,7 +201,7 @@ static inline void tracehook_report_exec(struct linux_binfmt *fmt, 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_exec(struct linux_binfmt *fmt, */ 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 void tracehook_report_exit(long *exit_code) */ 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 @@ static inline void tracehook_report_clone_complete(int trace, 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_clone_complete(int trace, 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); } /** |