113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/* fclose replacement.
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Copyright (C) 2008-2022 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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#include <config.h>
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/* Specification. */
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include "freading.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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#undef fclose
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#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
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static int
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fclose_nothrow (FILE *fp)
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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 = fclose (fp);
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}
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CATCH_MSVC_INVAL
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{
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result = EOF;
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errno = EBADF;
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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 fclose_nothrow fclose
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#endif
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/* Override fclose() to call the overridden fflush() or close(). */
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int
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rpl_fclose (FILE *fp)
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{
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int saved_errno = 0;
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int fd;
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int result = 0;
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/* Don't change behavior on memstreams. */
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fd = fileno (fp);
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if (fd < 0)
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return fclose_nothrow (fp);
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/* We only need to flush the file if it is not reading or if it is
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seekable. This only guarantees the file position of input files
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if the fflush module is also in use. */
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if ((!freading (fp) || lseek (fileno (fp), 0, SEEK_CUR) != -1)
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&& fflush (fp))
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saved_errno = errno;
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/* fclose() calls close(), but we need to also invoke all hooks that our
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overridden close() function invokes. See lib/close.c. */
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#if WINDOWS_SOCKETS
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/* Call the overridden close(), then the original fclose().
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Note about multithread-safety: There is a race condition where some
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other thread could open fd between our close and fclose. */
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if (close (fd) < 0 && saved_errno == 0)
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saved_errno = errno;
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fclose_nothrow (fp); /* will fail with errno = EBADF,
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if we did not lose a race */
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#else /* !WINDOWS_SOCKETS */
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/* Call fclose() and invoke all hooks of the overridden close(). */
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# if REPLACE_FCHDIR
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/* Note about multithread-safety: There is a race condition here as well.
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Some other thread could open fd between our calls to fclose and
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_gl_unregister_fd. */
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result = fclose_nothrow (fp);
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if (result == 0)
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_gl_unregister_fd (fd);
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# else
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/* No race condition here. */
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result = fclose_nothrow (fp);
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# endif
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#endif /* !WINDOWS_SOCKETS */
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if (saved_errno != 0)
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{
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errno = saved_errno;
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result = EOF;
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}
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return result;
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}
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