The only select() test that passes an fd_set uses fd 1, so nothing noticed that the FD_* macros used the wrong bits for fds 31-63 of each word on 64-bit architectures.
Add a test that FD_SET() and FD_CLR() change exactly one fd, for every fd below FD_SETSIZE, and one that select() reports a readable pipe duplicated to fd 40, which also checks that the macros agree with the kernel on the layout of the set. Assisted-by: LLM Signed-off-by: Danish Khateeb <[email protected]> --- tools/testing/selftests/nolibc/nolibc-test.c | 54 ++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index f62183a46205..d9a8bfd4b21b 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1369,6 +1369,58 @@ int test_pipe(void) return !!memcmp(buf, msg, len); } +int test_fd_set(void) +{ + fd_set fds; + int fd, i; + + for (fd = 0; fd < FD_SETSIZE; fd++) { + /* FD_SET() must set this fd and no other */ + FD_ZERO(&fds); + FD_SET(fd, &fds); + for (i = 0; i < FD_SETSIZE; i++) + if (!!FD_ISSET(i, &fds) != (i == fd)) + return 1; + + /* FD_CLR() must clear this fd and no other */ + for (i = 0; i < FD_SETSIZE; i++) + FD_SET(i, &fds); + FD_CLR(fd, &fds); + for (i = 0; i < FD_SETSIZE; i++) + if (!!FD_ISSET(i, &fds) != (i != fd)) + return 1; + } + + return 0; +} + +int test_select_high_fd(void) +{ + struct timeval tv = { 0 }; + int pipefd[2], fd, ret = 1; + fd_set fds; + + if (pipe(pipefd) == -1) + return 1; + + /* fd 40 is in the upper half of a 64-bit fd_set word */ + fd = dup2(pipefd[0], 40); + if (fd == -1) + goto out; + + write(pipefd[1], "x", 1); + FD_ZERO(&fds); + FD_SET(fd, &fds); + if (select(fd + 1, &fds, NULL, NULL, &tv) == 1 && FD_ISSET(fd, &fds)) + ret = 0; + + close(fd); +out: + close(pipefd[0]); + close(pipefd[1]); + return ret; +} + int test_rlimit(void) { struct rlimit rlim = { @@ -1711,6 +1763,7 @@ int run_syscall(int min, int max) CASE_TEST(execve_root); EXPECT_SYSER(1, execve("/", (char*[]){ [0] = (char []){"/"}, [1] = NULL }, NULL), -1, EACCES); break; CASE_TEST(fchdir_stdin); EXPECT_SYSER(1, fchdir(STDIN_FILENO), -1, ENOTDIR); break; CASE_TEST(fchdir_badfd); EXPECT_SYSER(1, fchdir(-1), -1, EBADF); break; + CASE_TEST(fd_set); EXPECT_ZR(1, test_fd_set()); break; CASE_TEST(fdopendir_notdir); EXPECT_SYSER(1, (uintptr_t)fdopendir(STDIN_FILENO), (uintptr_t)NULL, ENOTDIR); break; CASE_TEST(file_stream); EXPECT_SYSZR(1, test_file_stream()); break; CASE_TEST(file_stream_wsr); EXPECT_SYSZR(1, test_file_stream_wsr()); break; @@ -1753,6 +1806,7 @@ int run_syscall(int min, int max) CASE_TEST(select_null); EXPECT_SYSZR(1, ({ struct timeval tv = { 0 }; select(0, NULL, NULL, NULL, &tv); })); break; CASE_TEST(select_stdout); EXPECT_SYSNE(1, ({ fd_set fds; FD_ZERO(&fds); FD_SET(1, &fds); select(2, NULL, &fds, NULL, NULL); }), -1); break; CASE_TEST(select_fault); EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break; + CASE_TEST(select_high_fd); EXPECT_SYSZR(1, test_select_high_fd()); break; CASE_TEST(sendfile); EXPECT_SYSZR(1, test_sendfile()); break; CASE_TEST(stat_blah); EXPECT_SYSER(1, stat("/proc/self/blah", &stat_buf), -1, ENOENT); break; CASE_TEST(stat_fault); EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break; -- 2.55.0
