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57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
/* Copyright (C) 1991-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <unistd.h>
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/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
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open the same file as FD is. Return FD2 or -1. */
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int
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__dup2 (int fd, int fd2)
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{
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int save;
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if (fd2 < 0
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#ifdef OPEN_MAX
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|| fd2 >= OPEN_MAX
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#endif
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)
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{
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__set_errno (EBADF);
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return -1;
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}
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/* Check if FD is kosher. */
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if (fcntl (fd, F_GETFL) < 0)
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return -1;
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if (fd == fd2)
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return fd2;
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/* This is not atomic. */
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save = errno;
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(void) close (fd2);
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__set_errno (save);
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return fcntl (fd, F_DUPFD, fd2);
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}
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libc_hidden_def (__dup2)
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weak_alias (__dup2, dup2)
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