190 lines
4 KiB
C
190 lines
4 KiB
C
/* Duplicate an open file descriptor to a specified file descriptor.
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Copyright (C) 1999, 2004-2007, 2009-2023 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* written by Paul Eggert */
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#include <config.h>
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/* Specification. */
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#undef dup2
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#if defined _WIN32 && ! defined __CYGWIN__
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/* Get declarations of the native Windows API functions. */
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# define WIN32_LEAN_AND_MEAN
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# include <windows.h>
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# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
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# include "msvc-inval.h"
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# endif
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/* Get _get_osfhandle. */
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# if GNULIB_MSVC_NOTHROW
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# include "msvc-nothrow.h"
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# else
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# include <io.h>
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# endif
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# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
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static int
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dup2_nothrow (int fd, int desired_fd)
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{
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int result;
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TRY_MSVC_INVAL
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{
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result = _dup2 (fd, desired_fd);
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}
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CATCH_MSVC_INVAL
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{
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errno = EBADF;
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result = -1;
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}
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DONE_MSVC_INVAL;
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return result;
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}
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# else
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# define dup2_nothrow _dup2
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# endif
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static int
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ms_windows_dup2 (int fd, int desired_fd)
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{
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int result;
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/* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
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dup2 (fd, fd) returns 0, but all further attempts to use fd in
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future dup2 calls will hang. */
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if (fd == desired_fd)
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{
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if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
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{
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errno = EBADF;
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return -1;
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}
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return fd;
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}
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/* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
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https://bugs.winehq.org/show_bug.cgi?id=21289 */
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if (desired_fd < 0)
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{
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errno = EBADF;
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return -1;
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}
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result = dup2_nothrow (fd, desired_fd);
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if (result == 0)
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result = desired_fd;
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return result;
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}
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# define dup2 ms_windows_dup2
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#elif defined __KLIBC__
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# include <InnoTekLIBC/backend.h>
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static int
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klibc_dup2dirfd (int fd, int desired_fd)
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{
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int tempfd;
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int dupfd;
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tempfd = open ("NUL", O_RDONLY);
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if (tempfd == -1)
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return -1;
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if (tempfd == desired_fd)
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{
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close (tempfd);
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char path[_MAX_PATH];
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if (__libc_Back_ioFHToPath (fd, path, sizeof (path)))
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return -1;
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return open(path, O_RDONLY);
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}
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dupfd = klibc_dup2dirfd (fd, desired_fd);
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close (tempfd);
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return dupfd;
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}
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static int
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klibc_dup2 (int fd, int desired_fd)
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{
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int dupfd;
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struct stat sbuf;
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dupfd = dup2 (fd, desired_fd);
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if (dupfd == -1 && errno == ENOTSUP \
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&& !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode))
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{
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close (desired_fd);
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return klibc_dup2dirfd (fd, desired_fd);
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}
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return dupfd;
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}
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# define dup2 klibc_dup2
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#endif
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int
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rpl_dup2 (int fd, int desired_fd)
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{
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int result;
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#ifdef F_GETFL
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/* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
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On Cygwin 1.5.x, dup2 (1, 1) returns 0.
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On Cygwin 1.7.17, dup2 (1, -1) dumps core.
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On Cygwin 1.7.25, dup2 (1, 256) can dump core.
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On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */
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# if HAVE_SETDTABLESIZE
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setdtablesize (desired_fd + 1);
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# endif
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if (desired_fd < 0)
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fd = desired_fd;
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if (fd == desired_fd)
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return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
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#endif
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result = dup2 (fd, desired_fd);
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/* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */
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if (result == -1 && errno == EMFILE)
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errno = EBADF;
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#if REPLACE_FCHDIR
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if (fd != desired_fd && result != -1)
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result = _gl_register_dup (fd, result);
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#endif
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return result;
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}
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