[asan] Zero initialize sem_t in sem_init.

Old version of sem_init (GLIBC_2.0) fails to initialize parts of
sem_t that are used in sem_timedwait. This is fixed in GLIBC_2.1,
but since ASan interceptors downgrade sem_* to the oldest available
version, this can introduce bugs that are only present in sanitized
build. Workaround by zero-initializing sem_t in sem_init.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@250113 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 32 insertions, 0 deletions

diff --git a/test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc b/test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc
new file mode 100644
index 000000000..f17453b2d
--- /dev/null
+++ b/test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc
@@ -0,0 +1,32 @@
+// RUN: %clangxx -O0 -g %s -lutil -o %t && %run %t
+// This test depends on the glibc layout of struct sem_t and checks that we
+// don't leave sem_t::private uninitialized.
+// UNSUPPORTED: android
+#include <assert.h>
+#include <semaphore.h>
+#include <string.h>
+
+void my_sem_init(bool priv, int value, unsigned *a, unsigned char *b) {
+  sem_t sem;
+  memset(&sem, 0xAB, sizeof(sem));
+  sem_init(&sem, priv, value);
+
+  char *p = (char *)&sem;
+  memcpy(a, p, sizeof(unsigned));
+  memcpy(b, p + sizeof(unsigned), sizeof(char));
+
+  sem_destroy(&sem);
+}
+
+int main() {
+  unsigned a;
+  unsigned char b;
+
+  my_sem_init(false, 42, &a, &b);
+  assert(a == 42);
+  assert(b != 0xAB);
+
+  my_sem_init(true, 43, &a, &b);
+  assert(a == 43);
+  assert(b != 0xAB);
+}