Enable usage of PTRACE_SEIZE

* defs.h: Define USE_SEIZE to 1. Remove PTRACE_SEIZE_DEVEL
and PTRACE_EVENT_STOP1.
* strace.c (ptrace_attach_or_seize): Replace PTRACE_SEIZE_DEVEL
with 0.
(trace): Do not check for PTRACE_EVENT_STOP1.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 8 insertions, 9 deletions

diff --git a/defs.h b/defs.h
index 9979fcbd9..7814bbd12 100644
--- a/defs.h
+++ b/defs.h
@@ -300,8 +300,10 @@ extern long ptrace(int, int, char *, long);
 # define PTRACE_EVENT_EXIT	6
 #endif
 
-/* Experimental code using PTRACE_SEIZE can be enabled here: */
-//# define USE_SEIZE 1
+/* Experimental code using PTRACE_SEIZE can be enabled here.
+ * This needs Linux kernel 3.4.x or later to work.
+ */
+#define USE_SEIZE 1
 
 #ifdef USE_SEIZE
 # undef PTRACE_SEIZE
@@ -310,11 +312,8 @@ extern long ptrace(int, int, char *, long);
 # define PTRACE_INTERRUPT	0x4207
 # undef PTRACE_LISTEN
 # define PTRACE_LISTEN		0x4208
-# undef PTRACE_SEIZE_DEVEL
-# define PTRACE_SEIZE_DEVEL	0x80000000
 # undef PTRACE_EVENT_STOP
-# define PTRACE_EVENT_STOP	7
-# define PTRACE_EVENT_STOP1	128
+# define PTRACE_EVENT_STOP	128
 #endif
 
 #if defined(I386)
diff --git a/strace.c b/strace.c
index 9d7ee7b31..e6d6d687f 100644
--- a/strace.c
+++ b/strace.c
@@ -335,7 +335,7 @@ ptrace_attach_or_seize(int pid)
 	int r;
 	if (!use_seize)
 		return ptrace(PTRACE_ATTACH, pid, 0, 0);
-	r = ptrace(PTRACE_SEIZE, pid, 0, PTRACE_SEIZE_DEVEL);
+	r = ptrace(PTRACE_SEIZE, pid, 0, 0);
 	if (r)
 		return r;
 	r = ptrace(PTRACE_INTERRUPT, pid, 0, 0);
@@ -1382,7 +1382,7 @@ test_ptrace_seize(void)
 	 * attaching tracee continues to run unless a trap condition occurs.
 	 * PTRACE_SEIZE doesn't affect signal or group stop state.
 	 */
-	if (ptrace(PTRACE_SEIZE, pid, 0, PTRACE_SEIZE_DEVEL) == 0) {
+	if (ptrace(PTRACE_SEIZE, pid, 0, 0) == 0) {
 		post_attach_sigstop = 0; /* this sets use_seize to 1 */
 	} else if (debug_flag) {
 		fprintf(stderr, "PTRACE_SEIZE doesn't work\n");
@@ -2074,7 +2074,7 @@ trace(void)
 		if (event != 0) {
 			/* Ptrace event */
 #ifdef USE_SEIZE
-			if (event == PTRACE_EVENT_STOP || event == PTRACE_EVENT_STOP1) {
+			if (event == PTRACE_EVENT_STOP) {
 				/*
 				 * PTRACE_INTERRUPT-stop or group-stop.
 				 * PTRACE_INTERRUPT-stop has sig == SIGTRAP here.