72 lines
1.8 KiB
C
72 lines
1.8 KiB
C
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/* An interface to read and write that retries after interrupts.
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Copyright (C) 1993-1994, 1998, 2002-2006, 2009-2022 Free Software
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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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#ifdef SAFE_WRITE
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# include "safe-write.h"
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#else
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# include "safe-read.h"
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#endif
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/* Get ssize_t. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <errno.h>
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#ifdef EINTR
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# define IS_EINTR(x) ((x) == EINTR)
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#else
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# define IS_EINTR(x) 0
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#endif
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#include "sys-limits.h"
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#ifdef SAFE_WRITE
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# define safe_rw safe_write
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# define rw write
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#else
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# define safe_rw safe_read
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# define rw read
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# undef const
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# define const /* empty */
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#endif
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/* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if
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interrupted. Return the actual number of bytes read(written), zero for EOF,
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or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error. */
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size_t
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safe_rw (int fd, void const *buf, size_t count)
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{
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for (;;)
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{
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ssize_t result = rw (fd, buf, count);
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if (0 <= result)
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return result;
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else if (IS_EINTR (errno))
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continue;
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else if (errno == EINVAL && SYS_BUFSIZE_MAX < count)
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count = SYS_BUFSIZE_MAX;
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else
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return result;
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}
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}
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