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/* An interface to read and write that retries after interrupts.
Copyright (C) 1993-1994, 1998, 2002-2006, 2009-2021 Free Software
Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#ifdef SAFE_WRITE
# include "safe-write.h"
#else
# include "safe-read.h"
#endif
/* Get ssize_t. */
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#ifdef EINTR
# define IS_EINTR(x) ((x) == EINTR)
#else
# define IS_EINTR(x) 0
#endif
#include "sys-limits.h"
#ifdef SAFE_WRITE
# define safe_rw safe_write
# define rw write
#else
# define safe_rw safe_read
# define rw read
# undef const
# define const /* empty */
#endif
/* Read(write) up to COUNT bytes at BUF from(to) descriptor FD, retrying if
interrupted. Return the actual number of bytes read(written), zero for EOF,
or SAFE_READ_ERROR(SAFE_WRITE_ERROR) upon error. */
size_t
safe_rw (int fd, void const *buf, size_t count)
{
for (;;)
{
ssize_t result = rw (fd, buf, count);
if (0 <= result)
return result;
else if (IS_EINTR (errno))
continue;
else if (errno == EINVAL && SYS_BUFSIZE_MAX < count)
count = SYS_BUFSIZE_MAX;
else
return result;
}
}
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