[PATCH v4 37/37] unwind: stacktrace capturing and mmap cache invalidating at trace_syscall_entering

[Masatake YAMATO]

Instead of handling stacktrace capturing and mmap cache invalidating
at sys_* functions, handle them at unified place
`trace_syscall_entering'.  For handling them the makers(SI and SE)
introduced at previous patches are referred.

The patch is simpler than its older version(v3).  The value of
`hide_log_until_execve' is just ignored.  I found the value is nothing
to do with this patch. `unwind_cache_invalidate' is mentioned only
once at `trace_syscall_exiting'. Both are suggested by Dmitry V. Levin <ldv at altlinux.org>.

Signed-off-by: Masatake YAMATO <yamato at redhat.com>
---
 mem.c     | 27 ---------------------------
 process.c | 13 -------------
 syscall.c | 14 ++++++++++++++
 3 files changed, 14 insertions(+), 40 deletions(-)

diff --git a/mem.c b/mem.c
index 1c36360..267773c 100644
--- a/mem.c
+++ b/mem.c
@@ -178,13 +178,6 @@ static int
 print_mmap(struct tcb *tcp, long *u_arg, unsigned long long offset)
 {
 	if (entering(tcp)) {
-#ifdef USE_LIBUNWIND
-		if (stack_trace_enabled) {
-			unwind_capture_stacktrace(tcp);
-			unwind_cache_invalidate(tcp);
-		}
-#endif
-
 		/* addr */
 		if (!u_arg[0])
 			tprints("NULL, ");
@@ -313,17 +306,7 @@ sys_munmap(struct tcb *tcp)
 	if (entering(tcp)) {
 		tprintf("%#lx, %lu",
 			tcp->u_arg[0], tcp->u_arg[1]);
-#ifdef USE_LIBUNWIND
-		if (stack_trace_enabled)
-			unwind_capture_stacktrace(tcp);
-#endif
-	}
-#ifdef USE_LIBUNWIND
-	else {
-		if (stack_trace_enabled)
-			unwind_cache_invalidate(tcp);
 	}
-#endif
 	return 0;
 }
 
@@ -334,17 +317,7 @@ sys_mprotect(struct tcb *tcp)
 		tprintf("%#lx, %lu, ",
 			tcp->u_arg[0], tcp->u_arg[1]);
 		printflags(mmap_prot, tcp->u_arg[2], "PROT_???");
-#ifdef USE_LIBUNWIND
-		if (stack_trace_enabled)
-			unwind_capture_stacktrace(tcp);
-#endif
 	}
-#ifdef USE_LIBUNWIND
-	else {
-		if (stack_trace_enabled)
-			unwind_cache_invalidate(tcp);
-	}
-#endif
 	return 0;
 }
 
diff --git a/process.c b/process.c
index 40cc263..e3837da 100644
--- a/process.c
+++ b/process.c
@@ -989,20 +989,7 @@ sys_execve(struct tcb *tcp)
 			printargv(tcp, tcp->u_arg[2]);
 			tprints("]");
 		}
-#ifdef USE_LIBUNWIND
-		if (stack_trace_enabled) {
-			unwind_capture_stacktrace(tcp);
-		}
-#endif
 	}
-#ifdef USE_LIBUNWIND
-	else {
-		if (stack_trace_enabled) {
-			unwind_cache_invalidate(tcp);
-		}
-	}
-#endif
-
 	return 0;
 }
 
diff --git a/syscall.c b/syscall.c
index 45714bf..4f2d290 100644
--- a/syscall.c
+++ b/syscall.c
@@ -2040,6 +2040,13 @@ trace_syscall_entering(struct tcb *tcp)
 		goto ret;
 	}
 
+#ifdef USE_LIBUNWIND
+	if (stack_trace_enabled) {
+		if (tcp->s_ent->sys_flags & STACKTRACE_CAPTURE_ON_ENTER)
+			unwind_capture_stacktrace(tcp);
+	}
+#endif
+
 	printleader(tcp);
 	if (tcp->qual_flg & UNDEFINED_SCNO)
 		tprintf("%s(", undefined_scno_name(tcp));
@@ -2513,6 +2520,13 @@ trace_syscall_exiting(struct tcb *tcp)
 	if (Tflag || cflag)
 		gettimeofday(&tv, NULL);
 
+#ifdef USE_LIBUNWIND
+	if (stack_trace_enabled) {
+		if (tcp->s_ent->sys_flags & STACKTRACE_INVALIDATE_CACHE)
+			unwind_cache_invalidate(tcp);
+	}
+#endif
+
 #if SUPPORTED_PERSONALITIES > 1
 	update_personality(tcp, tcp->currpers);
 #endif
-- 
1.9.0