syscall(3)'s return type should be long.
This doesn't require us to change any of the syscall implementations
because (a) the LP32 ones have sizeof(int) == sizeof(long) anyway,
which is how we never noticed this bug before and (b) the LP64 ones
all use a 64-bit register for the result (and for the syscall number
too).
Bug: https://code.google.com/p/android/issues/detail?id=73952
Bug: 16568314
(cherry picked from commit 21972b61ec0572395c5684eebc6cc7b3a4c9e3be)
Change-Id: Ifbc424be29e5650ec72a24df25dd35f24fdd5b3c
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 58c9ad9..2a65657 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -20,6 +20,7 @@
#include <errno.h>
#include <fcntl.h>
+#include <limits.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/syscall.h>
@@ -212,6 +213,14 @@
ASSERT_EQ(EBADF, errno);
}
+TEST(unistd, syscall_long) {
+ // Check that syscall(3) correctly returns long results.
+ // https://code.google.com/p/android/issues/detail?id=73952
+ // We assume that the break is > 4GiB, but this is potentially flaky.
+ uintptr_t p = reinterpret_cast<uintptr_t>(sbrk(0));
+ ASSERT_EQ(p, static_cast<uintptr_t>(syscall(__NR_brk, 0)));
+}
+
TEST(unistd, alarm) {
ASSERT_EQ(0U, alarm(0));
}