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/*
* SPDX-FileCopyrightText: 2023, Christian Göttsche <cgzones@googlemail.com>
* SPDX-FileCopyrightText: 2023, Alejandro Colomar <alx@kernel.org>
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "config.h"
#ident "$Id$"
#include <errno.h>
#include <unistd.h>
#include "prototypes.h"
/*
* SYNOPSIS
* int write_full(int fd, const void *buf, size_t count);
*
* ARGUMENTS
* fd File descriptor.
* buf Source buffer to write(2) into 'fd'.
* count Size of 'buf'.
*
* DESCRIPTION
* Write 'count' bytes from the buffer starting at 'buf' to the
* file referred to by 'fd'.
*
* This function is similar to write(2), except that it retries
* in case of a short write.
*
* Since this function either performs a full write, or fails, the
* return value is simpler than for write(2).
*
* RETURN VALUE
* 0 On success.
* -1 On error.
*
* ERRORS
* See write(2).
*
* CAVEATS
* This function can still perform partial writes: if the function
* fails in the loop after one or more write(2) calls have
* succeeded, it will report a failure, but some data may have been
* written. In such a case, it's the caller's responsibility to
* make sure that the partial write is not problematic, and
* remediate it if it is --maybe by trying to remove the file--.
*/
int
write_full(int fd, const void *buf, size_t count)
{
ssize_t w;
const unsigned char *p;
p = buf;
while (count > 0) {
w = write(fd, p, count);
if (w == -1) {
if (errno == EINTR)
continue;
return -1;
}
p += w;
count -= w;
}
return 0;
}
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