[PATCH 3/5] tracing: Add get_syscall_name()

[Tom Zanussi <tom.zanussi@linux.intel.com>]

Add a utility function to grab the syscall name from the syscall
metadata, given a syscall id.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 kernel/trace/trace.h          |  9 +++++++++
 kernel/trace/trace_syscalls.c | 11 +++++++++++
 2 files changed, 20 insertions(+)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9032cf3..457fb4f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1277,4 +1277,13 @@ int perf_ftrace_event_register(struct ftrace_event_call *call,
 #define perf_ftrace_event_register NULL
 #endif
 
+#ifdef CONFIG_FTRACE_SYSCALLS
+const char *get_syscall_name(int syscall);
+#else
+static inline const char *get_syscall_name(int syscall)
+{
+	return NULL;
+}
+#endif /* CONFIG_FTRACE_SYSCALLS */
+
 #endif /* _LINUX_KERNEL_TRACE_H */
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 759d5e0..1abb3396 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -106,6 +106,17 @@ static struct syscall_metadata *syscall_nr_to_meta(int nr)
 	return syscalls_metadata[nr];
 }
 
+const char *get_syscall_name(int syscall)
+{
+	struct syscall_metadata *entry;
+
+	entry = syscall_nr_to_meta(syscall);
+	if (!entry)
+		return NULL;
+
+	return entry->name;
+}
+
 static enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags,
 		    struct trace_event *event)
-- 
1.8.3.1