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