libc: enable sprintf FORTIFY_SOURCE under clang

clang doesn't support __builtin_va_arg_pack(), so we have
to use #define instead.

Change-Id: I2ee75e6267d60cdf997fee6b9b0547bf68f062a1
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 511bcd2..42c6d34 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -450,10 +450,11 @@
 __END_DECLS
 #endif /* _GNU_SOURCE */
 
-#if defined(__BIONIC_FORTIFY) && !defined(__clang__)
+#if defined(__BIONIC_FORTIFY)
 
 __BEGIN_DECLS
 
+#if !defined(__clang__)
 __BIONIC_FORTIFY_INLINE
 __printflike(3, 0)
 int vsnprintf(char *dest, size_t size, const char *format, __va_list ap)
@@ -475,7 +476,11 @@
     return __builtin___snprintf_chk(str, size, 0,
         __bos(str), format, __builtin_va_arg_pack());
 }
+#endif /* !defined(__clang__) */
 
+#if defined(__clang__)
+#define sprintf(dest, ...) __builtin___sprintf_chk(dest, 0, __bos(dest), __VA_ARGS__)
+#else
 __BIONIC_FORTIFY_INLINE
 __printflike(2, 3)
 int sprintf(char *dest, const char *format, ...)
@@ -483,7 +488,9 @@
     return __builtin___sprintf_chk(dest, 0,
         __bos(dest), format, __builtin_va_arg_pack());
 }
+#endif
 
+#if !defined(__clang__)
 extern char *__fgets_real(char *, int, FILE *)
     __asm__(__USER_LABEL_PREFIX__ "fgets");
 __errordecl(__fgets_too_big_error, "fgets called with size bigger than buffer");
@@ -521,8 +528,10 @@
     return __fgets_chk(dest, size, stream, bos);
 }
 
+#endif /* !defined(__clang__) */
+
 __END_DECLS
 
-#endif /* defined(__BIONIC_FORTIFY) && !defined(__clang__) */
+#endif /* defined(__BIONIC_FORTIFY) */
 
 #endif /* _STDIO_H_ */
diff --git a/tests/fortify1_test.cpp b/tests/fortify1_test.cpp
index b8751bb..9d40404 100644
--- a/tests/fortify1_test.cpp
+++ b/tests/fortify1_test.cpp
@@ -100,6 +100,12 @@
   ASSERT_EXIT(sprintf(buf, "%s", source_buf), testing::KilledBySignal(SIGABRT), "");
 }
 
+TEST(Fortify1_DeathTest, sprintf2_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[5];
+  ASSERT_EXIT(sprintf(buf, "aaaaa"), testing::KilledBySignal(SIGABRT), "");
+}
+
 TEST(Fortify1_DeathTest, strncat_fortified) {
   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   char buf[10];
diff --git a/tests/fortify1_test_clang.cpp b/tests/fortify1_test_clang.cpp
index fed9f13..b4ded33 100644
--- a/tests/fortify1_test_clang.cpp
+++ b/tests/fortify1_test_clang.cpp
@@ -92,6 +92,20 @@
 
 #endif
 
+TEST(Fortify1_Clang_DeathTest, sprintf_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[10];
+  char source_buf[15];
+  memcpy(source_buf, "12345678901234", 15);
+  ASSERT_EXIT(sprintf(buf, "%s", source_buf), testing::KilledBySignal(SIGABRT), "");
+}
+
+TEST(Fortify1_Clang_DeathTest, sprintf2_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[5];
+  ASSERT_EXIT(sprintf(buf, "aaaaa"), testing::KilledBySignal(SIGABRT), "");
+}
+
 TEST(Fortify1_Clang_DeathTest, strncat_fortified) {
   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   char buf[10];
diff --git a/tests/fortify2_test.cpp b/tests/fortify2_test.cpp
index b6f6661..2f50038 100644
--- a/tests/fortify2_test.cpp
+++ b/tests/fortify2_test.cpp
@@ -46,6 +46,13 @@
               testing::KilledBySignal(SIGABRT), "");
 }
 
+TEST(Fortify2_DeathTest, sprintf2_fortified2) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  foo myfoo;
+  ASSERT_EXIT(sprintf(myfoo.a, "0123456789"),
+              testing::KilledBySignal(SIGABRT), "");
+}
+
 #if __BIONIC__
 // zero sized target with "\0" source (should fail)
 TEST(Fortify2_DeathTest, strcpy_fortified2) {
@@ -229,6 +236,12 @@
   ASSERT_EXIT(sprintf(buf, "%s", source_buf), testing::KilledBySignal(SIGABRT), "");
 }
 
+TEST(Fortify2_DeathTest, sprintf2_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[5];
+  ASSERT_EXIT(sprintf(buf, "aaaaa"), testing::KilledBySignal(SIGABRT), "");
+}
+
 TEST(Fortify2_DeathTest, strncat_fortified) {
   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   char buf[10];
diff --git a/tests/fortify2_test_clang.cpp b/tests/fortify2_test_clang.cpp
index d8a0ba6..54a6e5a 100644
--- a/tests/fortify2_test_clang.cpp
+++ b/tests/fortify2_test_clang.cpp
@@ -109,6 +109,20 @@
 }
 #endif
 
+TEST(Fortify2_Clang_DeathTest, sprintf_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[10];
+  char source_buf[15];
+  memcpy(source_buf, "12345678901234", 15);
+  ASSERT_EXIT(sprintf(buf, "%s", source_buf), testing::KilledBySignal(SIGABRT), "");
+}
+
+TEST(Fortify2_Clang_DeathTest, sprintf2_fortified) {
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+  char buf[5];
+  ASSERT_EXIT(sprintf(buf, "aaaaa"), testing::KilledBySignal(SIGABRT), "");
+}
+
 TEST(Fortify2_Clang_DeathTest, strncat_fortified) {
   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   char buf[10];