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Diffstat (limited to 'gnulib-tests/test-dup-safer.c')
| -rw-r--r-- | gnulib-tests/test-dup-safer.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/gnulib-tests/test-dup-safer.c b/gnulib-tests/test-dup-safer.c new file mode 100644 index 0000000..c2de300 --- /dev/null +++ b/gnulib-tests/test-dup-safer.c @@ -0,0 +1,179 @@ +/* Test that dup_safer leaves standard fds alone. + Copyright (C) 2009-2023 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 <fcntl.h> +#include <errno.h> +#include <stdio.h> +#include <unistd.h> + +#include "binary-io.h" +#include "cloexec.h" + +#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 + +#if !O_BINARY +# define set_binary_mode(f,m) zero () +static int zero (void) { return 0; } +#endif + +/* This test intentionally closes stderr. So, we arrange to have fd 10 + (outside the range of interesting fd's during the test) set up to + duplicate the original stderr. */ + +#define BACKUP_STDERR_FILENO 10 +#define ASSERT_STREAM myerr +#include "macros.h" + +static FILE *myerr; + +/* Return true if FD is open. */ +static bool +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 +} + +/* Return true if FD is open and inheritable across exec/spawn. */ +static bool +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 +} + +/* Return true if FD is open in the given MODE, which is either + O_TEXT or O_BINARY. */ +static bool +is_mode (int fd, int mode) +{ + int value = set_binary_mode (fd, O_BINARY); + set_binary_mode (fd, value); + return mode == value; +} + +#define witness "test-dup-safer.txt" + +int +main (void) +{ + int i; + int fd; + int bad_fd = getdtablesize (); + + /* We close fd 2 later, so save it in fd 10. */ + if (dup2 (STDERR_FILENO, BACKUP_STDERR_FILENO) != BACKUP_STDERR_FILENO + || (myerr = fdopen (BACKUP_STDERR_FILENO, "w")) == NULL) + return 2; + + /* Create file for later checks. */ + fd = creat (witness, 0600); + ASSERT (STDERR_FILENO < fd); + + /* Four iterations, with progressively more standard descriptors + closed. */ + for (i = -1; i <= STDERR_FILENO; i++) + { + if (0 <= i) + ASSERT (close (i) == 0); + + /* Detect errors. */ + errno = 0; + ASSERT (dup (-1) == -1); + ASSERT (errno == EBADF); + errno = 0; + ASSERT (dup (bad_fd) == -1); + ASSERT (errno == EBADF); + close (fd + 1); + errno = 0; + ASSERT (dup (fd + 1) == -1); + ASSERT (errno == EBADF); + + /* Preserve text vs. binary. */ + set_binary_mode (fd, O_BINARY); + ASSERT (dup (fd) == fd + 1); + ASSERT (is_open (fd + 1)); + ASSERT (is_inheritable (fd + 1)); + ASSERT (is_mode (fd + 1, O_BINARY)); + + ASSERT (close (fd + 1) == 0); + set_binary_mode (fd, O_TEXT); + ASSERT (dup (fd) == fd + 1); + ASSERT (is_open (fd + 1)); + ASSERT (is_inheritable (fd + 1)); + ASSERT (is_mode (fd + 1, O_TEXT)); + + /* Create cloexec copy. */ + ASSERT (close (fd + 1) == 0); + ASSERT (fd_safer_flag (dup_cloexec (fd), O_CLOEXEC) == fd + 1); + ASSERT (set_cloexec_flag (fd + 1, true) == 0); + ASSERT (is_open (fd + 1)); + ASSERT (!is_inheritable (fd + 1)); + ASSERT (close (fd) == 0); + + /* dup always creates inheritable copies. Also, check that + earliest slot past std fds is used. */ + ASSERT (dup (fd + 1) == fd); + ASSERT (is_open (fd)); + ASSERT (is_inheritable (fd)); + ASSERT (close (fd + 1) == 0); + } + + /* Cleanup. */ + ASSERT (close (fd) == 0); + ASSERT (unlink (witness) == 0); + + return 0; +} |