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Diffstat (limited to 'tests/test-dup2.c')
-rw-r--r-- | tests/test-dup2.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/tests/test-dup2.c b/tests/test-dup2.c new file mode 100644 index 0000000..1041525 --- /dev/null +++ b/tests/test-dup2.c @@ -0,0 +1,222 @@ +/* Test duplicating file descriptors. + Copyright (C) 2009-2022 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Eric Blake <ebb9@byu.net>, 2009. */ + +#include <config.h> + +#include <unistd.h> + +#include "signature.h" +SIGNATURE_CHECK (dup2, int, (int, int)); + +#include <errno.h> +#include <fcntl.h> + +#if HAVE_SYS_RESOURCE_H +# include <sys/resource.h> +#endif + +#include "binary-io.h" + +#if GNULIB_TEST_CLOEXEC +# include "cloexec.h" +#endif + +#if defined _WIN32 && ! defined __CYGWIN__ +/* Get declarations of the native Windows API functions. */ +# define WIN32_LEAN_AND_MEAN +# include <windows.h> +/* Get _get_osfhandle. */ +# if GNULIB_MSVC_NOTHROW +# include "msvc-nothrow.h" +# else +# include <io.h> +# endif +#endif + +#include "macros.h" + +/* Return non-zero if FD is open. */ +static int +is_open (int fd) +{ +#if defined _WIN32 && ! defined __CYGWIN__ + /* On native Windows, the initial state of unassigned standard file + descriptors is that they are open but point to an + INVALID_HANDLE_VALUE, and there is no fcntl. */ + return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE; +#else +# ifndef F_GETFL +# error Please port fcntl to your platform +# endif + return 0 <= fcntl (fd, F_GETFL); +#endif +} + +#if GNULIB_TEST_CLOEXEC +/* Return non-zero if FD is open and inheritable across exec/spawn. */ +static int +is_inheritable (int fd) +{ +# if defined _WIN32 && ! defined __CYGWIN__ + /* On native Windows, the initial state of unassigned standard file + descriptors is that they are open but point to an + INVALID_HANDLE_VALUE, and there is no fcntl. */ + HANDLE h = (HANDLE) _get_osfhandle (fd); + DWORD flags; + if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0) + return 0; + return (flags & HANDLE_FLAG_INHERIT) != 0; +# else +# ifndef F_GETFD +# error Please port fcntl to your platform +# endif + int i = fcntl (fd, F_GETFD); + return 0 <= i && (i & FD_CLOEXEC) == 0; +# endif +} +#endif /* GNULIB_TEST_CLOEXEC */ + +#if !O_BINARY +# define set_binary_mode(f,m) zero () +static int zero (void) { return 0; } +#endif + +/* Return non-zero if FD is open in the given MODE, which is either + O_TEXT or O_BINARY. */ +static int +is_mode (int fd, int mode) +{ + int value = set_binary_mode (fd, O_BINARY); + set_binary_mode (fd, value); + return mode == value; +} + +int +main (void) +{ + const char *file = "test-dup2.tmp"; + char buffer[1]; + int bad_fd = getdtablesize (); + int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600); + + /* Assume std descriptors were provided by invoker. */ + ASSERT (STDERR_FILENO < fd); + ASSERT (is_open (fd)); + /* Ignore any other fd's leaked into this process. */ + close (fd + 1); + close (fd + 2); + ASSERT (!is_open (fd + 1)); + ASSERT (!is_open (fd + 2)); + + /* Assigning to self must be a no-op. */ + ASSERT (dup2 (fd, fd) == fd); + ASSERT (is_open (fd)); + + /* The source must be valid. */ + errno = 0; + ASSERT (dup2 (-1, fd) == -1); + ASSERT (errno == EBADF); + close (99); + errno = 0; + ASSERT (dup2 (99, fd) == -1); + ASSERT (errno == EBADF); + errno = 0; + ASSERT (dup2 (AT_FDCWD, fd) == -1); + ASSERT (errno == EBADF); + ASSERT (is_open (fd)); + + /* If the source is not open, then the destination is unaffected. */ + errno = 0; + ASSERT (dup2 (fd + 1, fd + 1) == -1); + ASSERT (errno == EBADF); + ASSERT (!is_open (fd + 1)); + errno = 0; + ASSERT (dup2 (fd + 1, fd) == -1); + ASSERT (errno == EBADF); + ASSERT (is_open (fd)); + + /* The destination must be valid. */ + errno = 0; + ASSERT (dup2 (fd, -2) == -1); + ASSERT (errno == EBADF); + if (bad_fd > 256) + { + ASSERT (dup2 (fd, 255) == 255); + ASSERT (dup2 (fd, 256) == 256); + ASSERT (close (255) == 0); + ASSERT (close (256) == 0); + } + ASSERT (dup2 (fd, bad_fd - 1) == bad_fd - 1); + ASSERT (close (bad_fd - 1) == 0); + errno = 0; + ASSERT (dup2 (fd, bad_fd) == -1); + ASSERT (errno == EBADF); + + /* Using dup2 can skip fds. */ + ASSERT (dup2 (fd, fd + 2) == fd + 2); + ASSERT (is_open (fd)); + ASSERT (!is_open (fd + 1)); + ASSERT (is_open (fd + 2)); + + /* Verify that dup2 closes the previous occupant of a fd. */ + ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1); + ASSERT (dup2 (fd + 1, fd) == fd); + ASSERT (close (fd + 1) == 0); + ASSERT (write (fd, "1", 1) == 1); + ASSERT (dup2 (fd + 2, fd) == fd); + ASSERT (lseek (fd, 0, SEEK_END) == 0); + ASSERT (write (fd + 2, "2", 1) == 1); + ASSERT (lseek (fd, 0, SEEK_SET) == 0); + ASSERT (read (fd, buffer, 1) == 1); + ASSERT (*buffer == '2'); + +#if GNULIB_TEST_CLOEXEC + /* Any new fd created by dup2 must not be cloexec. */ + ASSERT (close (fd + 2) == 0); + ASSERT (dup_cloexec (fd) == fd + 1); + ASSERT (!is_inheritable (fd + 1)); + ASSERT (dup2 (fd + 1, fd + 1) == fd + 1); + ASSERT (!is_inheritable (fd + 1)); + ASSERT (dup2 (fd + 1, fd + 2) == fd + 2); + ASSERT (!is_inheritable (fd + 1)); + ASSERT (is_inheritable (fd + 2)); + errno = 0; + ASSERT (dup2 (fd + 1, -1) == -1); + ASSERT (errno == EBADF); + ASSERT (!is_inheritable (fd + 1)); +#endif + + /* On systems that distinguish between text and binary mode, dup2 + reuses the mode of the source. */ + set_binary_mode (fd, O_BINARY); + ASSERT (is_mode (fd, O_BINARY)); + ASSERT (dup2 (fd, fd + 1) == fd + 1); + ASSERT (is_mode (fd + 1, O_BINARY)); + set_binary_mode (fd, O_TEXT); + ASSERT (is_mode (fd, O_TEXT)); + ASSERT (dup2 (fd, fd + 1) == fd + 1); + ASSERT (is_mode (fd + 1, O_TEXT)); + + /* Clean up. */ + ASSERT (close (fd + 2) == 0); + ASSERT (close (fd + 1) == 0); + ASSERT (close (fd) == 0); + ASSERT (unlink (file) == 0); + + return 0; +} |