| /* Test duplicating file descriptors. |
| Copyright (C) 2009-2020 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 setmode(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 = setmode (fd, O_BINARY); |
| setmode (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. */ |
| setmode (fd, O_BINARY); |
| ASSERT (is_mode (fd, O_BINARY)); |
| ASSERT (dup2 (fd, fd + 1) == fd + 1); |
| ASSERT (is_mode (fd + 1, O_BINARY)); |
| setmode (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; |
| } |