ptrace: implement PTRACE_SEIZE

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index b5f55ca1f43f8994d86b58d988dd28d158a64d29..589292f3853013ff830668a6027e7049e5409816 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1873,21 +1873,26 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
        recalc_sigpending_tsk(current);
 }
 
-void ptrace_notify(int exit_code)
+static void ptrace_do_notify(int signr, int exit_code, int why)
 {
        siginfo_t info;
 
-       BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
-
        memset(&info, 0, sizeof info);
-       info.si_signo = SIGTRAP;
+       info.si_signo = signr;
        info.si_code = exit_code;
        info.si_pid = task_pid_vnr(current);
        info.si_uid = current_uid();
 
        /* Let the debugger run.  */
+       ptrace_stop(exit_code, why, 1, &info);
+}
+
+void ptrace_notify(int exit_code)
+{
+       BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+
        spin_lock_irq(&current->sighand->siglock);
-       ptrace_stop(exit_code, CLD_TRAPPED, 1, &info);
+       ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
        spin_unlock_irq(&current->sighand->siglock);
 }
 
@@ -2017,7 +2022,13 @@ static bool do_signal_stop(int signr)
 /**
  * do_jobctl_trap - take care of ptrace jobctl traps
  *
- * It is currently used only to trap for group stop while ptraced.
+ * When PT_SEIZED, it's used for both group stop and explicit
+ * SEIZE/INTERRUPT traps.  Both generate PTRACE_EVENT_STOP trap with
+ * accompanying siginfo.  If stopped, lower eight bits of exit_code contain
+ * the stop signal; otherwise, %SIGTRAP.
+ *
+ * When !PT_SEIZED, it's used only for group stop trap with stop signal
+ * number as exit_code and no siginfo.
  *
  * CONTEXT:
  * Must be called with @current->sighand->siglock held, which may be
@@ -2025,11 +2036,21 @@ static bool do_signal_stop(int signr)
  */
 static void do_jobctl_trap(void)
 {
+       struct signal_struct *signal = current->signal;
        int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
 
-       WARN_ON_ONCE(!signr);
-       ptrace_stop(signr, CLD_STOPPED, 0, NULL);
-       current->exit_code = 0;
+       if (current->ptrace & PT_SEIZED) {
+               if (!signal->group_stop_count &&
+                   !(signal->flags & SIGNAL_STOP_STOPPED))
+                       signr = SIGTRAP;
+               WARN_ON_ONCE(!signr);
+               ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
+                                CLD_STOPPED);
+       } else {
+               WARN_ON_ONCE(!signr);
+               ptrace_stop(signr, CLD_STOPPED, 0, NULL);
+               current->exit_code = 0;
+       }
 }
 
 static int ptrace_signal(int signr, siginfo_t *info,