| 1 | /* Test duplicating file descriptors.
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| 2 | Copyright (C) 2009-2012 Free Software Foundation, Inc.
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| 3 |
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| 4 | This program is free software: you can redistribute it and/or modify
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| 5 | it under the terms of the GNU General Public License as published by
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| 6 | the Free Software Foundation; either version 3 of the License, or
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| 7 | (at your option) any later version.
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| 8 |
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| 9 | This program is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU General Public License
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| 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */
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| 16 |
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| 17 | /* Written by Eric Blake <ebb9@byu.net>, 2009. */
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| 18 |
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| 19 | #include <config.h>
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| 20 |
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| 21 | #include <unistd.h>
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| 22 |
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| 23 | #include "signature.h"
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| 24 | SIGNATURE_CHECK (dup2, int, (int, int));
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| 25 |
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| 26 | #include <errno.h>
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| 27 | #include <fcntl.h>
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| 28 |
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| 29 | #include "binary-io.h"
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| 30 |
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| 31 | #if GNULIB_TEST_CLOEXEC
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| 32 | # include "cloexec.h"
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| 33 | #endif
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| 34 |
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| 35 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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| 36 | /* Get declarations of the native Windows API functions. */
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| 37 | # define WIN32_LEAN_AND_MEAN
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| 38 | # include <windows.h>
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| 39 | /* Get _get_osfhandle. */
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| 40 | # include "msvc-nothrow.h"
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| 41 | #endif
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| 42 |
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| 43 | #include "macros.h"
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| 44 |
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| 45 | /* Return non-zero if FD is open. */
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| 46 | static int
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| 47 | is_open (int fd)
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| 48 | {
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| 49 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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| 50 | /* On native Windows, the initial state of unassigned standard file
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| 51 | descriptors is that they are open but point to an
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| 52 | INVALID_HANDLE_VALUE, and there is no fcntl. */
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| 53 | return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
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| 54 | #else
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| 55 | # ifndef F_GETFL
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| 56 | # error Please port fcntl to your platform
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| 57 | # endif
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| 58 | return 0 <= fcntl (fd, F_GETFL);
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| 59 | #endif
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| 60 | }
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| 61 |
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| 62 | #if GNULIB_TEST_CLOEXEC
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| 63 | /* Return non-zero if FD is open and inheritable across exec/spawn. */
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| 64 | static int
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| 65 | is_inheritable (int fd)
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| 66 | {
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| 67 | # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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| 68 | /* On native Windows, the initial state of unassigned standard file
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| 69 | descriptors is that they are open but point to an
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| 70 | INVALID_HANDLE_VALUE, and there is no fcntl. */
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| 71 | HANDLE h = (HANDLE) _get_osfhandle (fd);
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| 72 | DWORD flags;
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| 73 | if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
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| 74 | return 0;
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| 75 | return (flags & HANDLE_FLAG_INHERIT) != 0;
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| 76 | # else
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| 77 | # ifndef F_GETFD
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| 78 | # error Please port fcntl to your platform
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| 79 | # endif
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| 80 | int i = fcntl (fd, F_GETFD);
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| 81 | return 0 <= i && (i & FD_CLOEXEC) == 0;
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| 82 | # endif
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| 83 | }
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| 84 | #endif /* GNULIB_TEST_CLOEXEC */
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| 85 |
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| 86 | #if !O_BINARY
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| 87 | # define setmode(f,m) zero ()
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| 88 | static int zero (void) { return 0; }
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| 89 | #endif
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| 90 |
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| 91 | /* Return non-zero if FD is open in the given MODE, which is either
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| 92 | O_TEXT or O_BINARY. */
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| 93 | static int
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| 94 | is_mode (int fd, int mode)
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| 95 | {
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| 96 | int value = setmode (fd, O_BINARY);
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| 97 | setmode (fd, value);
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| 98 | return mode == value;
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| 99 | }
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| 100 |
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| 101 | int
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| 102 | main (void)
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| 103 | {
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| 104 | const char *file = "test-dup2.tmp";
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| 105 | char buffer[1];
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| 106 | int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);
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| 107 |
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| 108 | /* Assume std descriptors were provided by invoker. */
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| 109 | ASSERT (STDERR_FILENO < fd);
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| 110 | ASSERT (is_open (fd));
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| 111 | /* Ignore any other fd's leaked into this process. */
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| 112 | close (fd + 1);
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| 113 | close (fd + 2);
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| 114 | ASSERT (!is_open (fd + 1));
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| 115 | ASSERT (!is_open (fd + 2));
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| 116 |
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| 117 | /* Assigning to self must be a no-op. */
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| 118 | ASSERT (dup2 (fd, fd) == fd);
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| 119 | ASSERT (is_open (fd));
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| 120 |
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| 121 | /* The source must be valid. */
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| 122 | errno = 0;
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| 123 | ASSERT (dup2 (-1, fd) == -1);
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| 124 | ASSERT (errno == EBADF);
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| 125 | errno = 0;
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| 126 | ASSERT (dup2 (99, fd) == -1);
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| 127 | ASSERT (errno == EBADF);
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| 128 | errno = 0;
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| 129 | ASSERT (dup2 (AT_FDCWD, fd) == -1);
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| 130 | ASSERT (errno == EBADF);
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| 131 | ASSERT (is_open (fd));
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| 132 |
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| 133 | /* If the source is not open, then the destination is unaffected. */
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| 134 | errno = 0;
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| 135 | ASSERT (dup2 (fd + 1, fd + 1) == -1);
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| 136 | ASSERT (errno == EBADF);
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| 137 | ASSERT (!is_open (fd + 1));
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| 138 | errno = 0;
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| 139 | ASSERT (dup2 (fd + 1, fd) == -1);
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| 140 | ASSERT (errno == EBADF);
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| 141 | ASSERT (is_open (fd));
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| 142 |
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| 143 | /* The destination must be valid. */
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| 144 | errno = 0;
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| 145 | ASSERT (dup2 (fd, -2) == -1);
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| 146 | ASSERT (errno == EBADF);
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| 147 | errno = 0;
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| 148 | ASSERT (dup2 (fd, 10000000) == -1);
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| 149 | ASSERT (errno == EBADF);
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| 150 |
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| 151 | /* Using dup2 can skip fds. */
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| 152 | ASSERT (dup2 (fd, fd + 2) == fd + 2);
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| 153 | ASSERT (is_open (fd));
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| 154 | ASSERT (!is_open (fd + 1));
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| 155 | ASSERT (is_open (fd + 2));
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| 156 |
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| 157 | /* Verify that dup2 closes the previous occupant of a fd. */
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| 158 | ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
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| 159 | ASSERT (dup2 (fd + 1, fd) == fd);
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| 160 | ASSERT (close (fd + 1) == 0);
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| 161 | ASSERT (write (fd, "1", 1) == 1);
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| 162 | ASSERT (dup2 (fd + 2, fd) == fd);
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| 163 | ASSERT (lseek (fd, 0, SEEK_END) == 0);
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| 164 | ASSERT (write (fd + 2, "2", 1) == 1);
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| 165 | ASSERT (lseek (fd, 0, SEEK_SET) == 0);
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| 166 | ASSERT (read (fd, buffer, 1) == 1);
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| 167 | ASSERT (*buffer == '2');
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| 168 |
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| 169 | #if GNULIB_TEST_CLOEXEC
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| 170 | /* Any new fd created by dup2 must not be cloexec. */
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| 171 | ASSERT (close (fd + 2) == 0);
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| 172 | ASSERT (dup_cloexec (fd) == fd + 1);
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| 173 | ASSERT (!is_inheritable (fd + 1));
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| 174 | ASSERT (dup2 (fd + 1, fd + 1) == fd + 1);
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| 175 | ASSERT (!is_inheritable (fd + 1));
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| 176 | ASSERT (dup2 (fd + 1, fd + 2) == fd + 2);
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| 177 | ASSERT (!is_inheritable (fd + 1));
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| 178 | ASSERT (is_inheritable (fd + 2));
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| 179 | errno = 0;
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| 180 | ASSERT (dup2 (fd + 1, -1) == -1);
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| 181 | ASSERT (errno == EBADF);
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| 182 | ASSERT (!is_inheritable (fd + 1));
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| 183 | #endif
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| 184 |
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| 185 | /* On systems that distinguish between text and binary mode, dup2
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| 186 | reuses the mode of the source. */
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| 187 | setmode (fd, O_BINARY);
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| 188 | ASSERT (is_mode (fd, O_BINARY));
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| 189 | ASSERT (dup2 (fd, fd + 1) == fd + 1);
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| 190 | ASSERT (is_mode (fd + 1, O_BINARY));
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| 191 | setmode (fd, O_TEXT);
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| 192 | ASSERT (is_mode (fd, O_TEXT));
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| 193 | ASSERT (dup2 (fd, fd + 1) == fd + 1);
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| 194 | ASSERT (is_mode (fd + 1, O_TEXT));
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| 195 |
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| 196 | /* Clean up. */
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| 197 | ASSERT (close (fd + 2) == 0);
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| 198 | ASSERT (close (fd + 1) == 0);
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| 199 | ASSERT (close (fd) == 0);
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| 200 | ASSERT (unlink (file) == 0);
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| 201 |
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| 202 | return 0;
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| 203 | }
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