[LTP] [PATCH v4 1/2] Add tst_gettid wrapper around gettid syscall

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 include/tst_pid.h | 8 ++++++++
 lib/tst_pid.c     | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/include/tst_pid.h b/include/tst_pid.h
index 774c845ce..951138abc 100644
--- a/include/tst_pid.h
+++ b/include/tst_pid.h
@@ -50,4 +50,12 @@ static inline int tst_get_free_pids(void (*cleanup_fn)(void))
  */
 pid_t tst_getpid(void);
 
+/*
+ * Direct gettid() syscall. Some glibc versions cache gettid() return value
+ * which can cause confusing issues for example in processes created by
+ * direct clone() syscall (without using the glibc wrapper). Use this function
+ * whenever the current process may be a thread of the main test process.
+ */
+pid_t tst_gettid(void);
+
 #endif /* TST_PID_H__ */
diff --git a/lib/tst_pid.c b/lib/tst_pid.c
index cfaa5db36..4e9dc7a52 100644
--- a/lib/tst_pid.c
+++ b/lib/tst_pid.c
@@ -166,3 +166,8 @@ pid_t tst_getpid(void)
 {
 	return syscall(SYS_getpid);
 }
+
+pid_t tst_gettid(void)
+{
+	return syscall(SYS_gettid);
+}
-- 
2.35.3