[PATCH v7 8/8] Add stacktrace filter action

[Nikolay Marchuk]

* defs.h (QUAL_STACKTRACE): Add new qual flag.
(stacktrace): Add macro for checking QUAL_STACKTRACE.
(stack_trace_enabled): Change description.
* filter_action.c (action_types): Declare and add new filter action type.
(update_default_flags): Update stack_trace_enabled.
* strace.c (stack_trace_enabled): Change description.
(init): Use filtering_parse for -k option.
* syscall.c (syscall_entering_trace, syscall_exiting_decode,
syscall_exiting_trace): Use stacktrace macro instead of
stack_trace_enabled.
* unwind.c (apply_stacktrace): Add filter action function.
---
 defs.h          |  6 +++++-
 filter_action.c | 11 +++++++++++
 strace.c        |  4 ++--
 syscall.c       |  6 +++---
 unwind.c        |  6 ++++++
 5 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/defs.h b/defs.h
index 13893f64..8604651a 100644
--- a/defs.h
+++ b/defs.h
@@ -271,6 +271,9 @@ struct tcb {
 #define QUAL_SIGNAL	0x100	/* report events with this signal */
 #define QUAL_READ	0x200	/* dump data read in this syscall */
 #define QUAL_WRITE	0x400	/* dump data written in this syscall */
+#ifdef USE_LIBUNWIND
+# define QUAL_STACKTRACE	0x800	/* do the stack trace */
+#endif
 
 #define DEFAULT_QUAL_FLAGS (QUAL_TRACE | QUAL_ABBREV | QUAL_VERBOSE)
 
@@ -281,6 +284,7 @@ struct tcb {
 #define abbrev(tcp)	((tcp)->qual_flg & QUAL_ABBREV)
 #define dump_read(tcp)	((tcp)->qual_flg & QUAL_READ)
 #define dump_write(tcp)	((tcp)->qual_flg & QUAL_WRITE)
+#define stacktrace(tcp)	((tcp)->qual_flg & QUAL_STACKTRACE)
 #define filtered(tcp)	((tcp)->flags & TCB_FILTERED)
 #define hide_log(tcp)	((tcp)->flags & TCB_HIDE_LOG)
 
@@ -383,7 +387,7 @@ extern struct path_set {
 extern unsigned xflag;
 extern unsigned followfork;
 #ifdef USE_LIBUNWIND
-/* if this is true do the stack trace for every system call */
+/* if this is true do the initialization of stack trace mechanism */
 extern bool stack_trace_enabled;
 #endif
 extern unsigned ptrace_setoptions;
diff --git a/filter_action.c b/filter_action.c
index 776ffded..2cffe7a2 100644
--- a/filter_action.c
+++ b/filter_action.c
@@ -41,6 +41,9 @@ DECL_FILTER_ACTION(write);
 DECL_FILTER_ACTION(raw);
 DECL_FILTER_ACTION(abbrev);
 DECL_FILTER_ACTION(verbose);
+# ifdef USE_LIBUNWIND
+DECL_FILTER_ACTION(stacktrace);
+# endif
 #undef DECL_FILTER_ACTION
 
 extern bool is_traced(struct tcb *);
@@ -81,6 +84,9 @@ static const struct filter_action_type {
 	FILTER_ACTION_TYPE(raw,		2, QUAL_RAW,		null,	is_traced),
 	FILTER_ACTION_TYPE(abbrev,	2, QUAL_ABBREV,		null,	is_traced),
 	FILTER_ACTION_TYPE(verbose,	2, QUAL_VERBOSE,	null,	is_traced),
+# ifdef USE_LIBUNWIND
+	FILTER_ACTION_TYPE(stacktrace,	2, QUAL_STACKTRACE,	null,	is_traced),
+# endif
 };
 #undef FILTER_ACTION_TYPE
 
@@ -163,6 +169,11 @@ add_action(const struct filter_action_type *type)
 	/* Update default_flags */
 	if (default_flags & type->qual_flg)
 		default_flags &= ~type->qual_flg;
+	/* Enable stack tracing. */
+#ifdef USE_LIBUNWIND
+	if (type->qual_flg & QUAL_STACKTRACE)
+		stack_trace_enabled = true;
+#endif
 
 	filter_actions = xreallocarray(filter_actions, ++nfilter_actions,
 				       sizeof(struct filter_action));
diff --git a/strace.c b/strace.c
index 79c5397e..d2011d0c 100644
--- a/strace.c
+++ b/strace.c
@@ -56,7 +56,7 @@ extern int optind;
 extern char *optarg;
 
 #ifdef USE_LIBUNWIND
-/* if this is true do the stack trace for every system call */
+/* if this is true do the initialization of stack trace mechanism */
 bool stack_trace_enabled;
 #endif
 
@@ -1693,7 +1693,7 @@ init(int argc, char *argv[])
 			break;
 #ifdef USE_LIBUNWIND
 		case 'k':
-			stack_trace_enabled = true;
+			filtering_parse("stacktrace(syscall all)");
 			break;
 #endif
 		case 'E':
diff --git a/syscall.c b/syscall.c
index b740dadb..ed463f92 100644
--- a/syscall.c
+++ b/syscall.c
@@ -686,7 +686,7 @@ syscall_entering_trace(struct tcb *tcp, unsigned int *sig)
 	}
 
 #ifdef USE_LIBUNWIND
-	if (stack_trace_enabled) {
+	if (stacktrace(tcp)) {
 		if (tcp->s_ent->sys_flags & STACKTRACE_CAPTURE_ON_ENTER)
 			unwind_capture_stacktrace(tcp);
 	}
@@ -732,7 +732,7 @@ syscall_exiting_decode(struct tcb *tcp, struct timeval *ptv)
 		gettimeofday(ptv, NULL);
 
 #ifdef USE_LIBUNWIND
-	if (stack_trace_enabled) {
+	if (stacktrace(tcp)) {
 		if (tcp->s_ent->sys_flags & STACKTRACE_INVALIDATE_CACHE)
 			unwind_cache_invalidate(tcp);
 	}
@@ -952,7 +952,7 @@ syscall_exiting_trace(struct tcb *tcp, struct timeval tv, int res)
 	line_ended();
 
 #ifdef USE_LIBUNWIND
-	if (stack_trace_enabled)
+	if (stacktrace(tcp))
 		unwind_print_stacktrace(tcp);
 #endif
 	return 0;
diff --git a/unwind.c b/unwind.c
index 919b63c3..caab4143 100644
--- a/unwind.c
+++ b/unwind.c
@@ -589,3 +589,9 @@ unwind_capture_stacktrace(struct tcb *tcp)
 		DPRINTF("tcp=%p, queue=%p", "captured", tcp, tcp->queue->head);
 	}
 }
+
+void
+apply_stacktrace(struct tcb *tcp, void *_priv_data)
+{
+	tcp->qual_flg |= QUAL_STACKTRACE;
+}
-- 
2.11.0