diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp index 9ffb36f812c45..3ab83977a4ee2 100644 --- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp +++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp @@ -288,26 +288,42 @@ bool SignalContext::IsStackOverflow() const { #endif // SANITIZER_GO +static void SetNonBlock(int fd) { + int res = fcntl(fd, F_GETFL, 0); + CHECK(!internal_iserror(res, nullptr)); + + res |= O_NONBLOCK; + res = fcntl(fd, F_SETFL, res); + CHECK(!internal_iserror(res, nullptr)); +} + bool IsAccessibleMemoryRange(uptr beg, uptr size) { - uptr page_size = GetPageSizeCached(); - // Checking too large memory ranges is slow. - CHECK_LT(size, page_size * 10); - int sock_pair[2]; - if (pipe(sock_pair)) - return false; - uptr bytes_written = - internal_write(sock_pair[1], reinterpret_cast(beg), size); - int write_errno; - bool result; - if (internal_iserror(bytes_written, &write_errno)) { - CHECK_EQ(EFAULT, write_errno); - result = false; - } else { - result = (bytes_written == size); + while (size) { + // `read` from `fds[0]` into a dummy buffer to free up the pipe buffer for + // more `write` is slower than just recreating a pipe. + int fds[2]; + CHECK_EQ(0, pipe(fds)); + + auto cleanup = at_scope_exit([&]() { + internal_close(fds[0]); + internal_close(fds[1]); + }); + + SetNonBlock(fds[1]); + + int write_errno; + uptr w = internal_write(fds[1], reinterpret_cast(beg), size); + if (internal_iserror(w, &write_errno)) { + if (write_errno == EINTR) + continue; + CHECK_EQ(EFAULT, write_errno); + return false; + } + size -= w; + beg += w; } - internal_close(sock_pair[0]); - internal_close(sock_pair[1]); - return result; + + return true; } void PlatformPrepareForSandboxing(void *args) { diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp index 803c8d39362e2..04890f2f5e2af 100644 --- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp +++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp @@ -80,6 +80,12 @@ TEST(SanitizerCommon, IsAccessibleMemoryRange) { EXPECT_FALSE(IsAccessibleMemoryRange(0x0, 2)); } +TEST(SanitizerCommon, IsAccessibleMemoryRangeLarge) { + InternalMmapVector buffer(10000 * GetPageSize()); + EXPECT_TRUE(IsAccessibleMemoryRange(reinterpret_cast(buffer.data()), + buffer.size())); +} + } // namespace __sanitizer #endif // SANITIZER_POSIX