93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
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/* Open a stream to a file.
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Copyright (C) 2007-2020 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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 General Public License for more details.
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You should have received a copy of the GNU 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 Bruno Haible <bruno@clisp.org>, 2007. */
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/* If the user's config.h happens to include <stdio.h>, let it include only
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the system's <stdio.h> here, so that orig_freopen doesn't recurse to
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rpl_freopen. */
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#define _GL_ALREADY_INCLUDING_STDIO_H
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#include <config.h>
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/* Get the original definition of freopen. It might be defined as a macro. */
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#include <stdio.h>
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#undef _GL_ALREADY_INCLUDING_STDIO_H
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#include <errno.h>
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static FILE *
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orig_freopen (const char *filename, const char *mode, FILE *stream)
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{
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return freopen (filename, mode, stream);
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}
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/* Specification. */
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/* Write "stdio.h" here, not <stdio.h>, otherwise OSF/1 5.1 DTK cc eliminates
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this include because of the preliminary #include <stdio.h> above. */
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#include "stdio.h"
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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FILE *
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rpl_freopen (const char *filename, const char *mode, FILE *stream)
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{
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FILE *result;
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#if defined _WIN32 && ! defined __CYGWIN__
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char const *null_device = "NUL";
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if (filename && strcmp (filename, "/dev/null") == 0)
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filename = null_device;
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#else
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char const *null_device = "/dev/null";
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#endif
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#ifdef __KLIBC__
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errno = 0;
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#endif
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result = orig_freopen (filename, mode, stream);
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if (!result)
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{
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#ifdef __KLIBC__
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/* On OS/2 kLIBC, freopen returns NULL even if it is successful
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if filename is NULL. */
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if (!filename && !errno)
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result = stream;
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#endif
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}
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else if (filename)
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{
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int fd = fileno (result);
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if (dup2 (fd, fd) < 0 && errno == EBADF)
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{
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int nullfd = open (null_device, O_RDONLY | O_CLOEXEC);
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int err = 0;
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if (nullfd != fd)
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{
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if (dup2 (nullfd, fd) < 0)
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err = 1;
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close (nullfd);
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}
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if (!err)
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result = orig_freopen (filename, mode, result);
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}
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}
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return result;
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}
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