GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/rcs/buf.c Lines: 53 88 60.2 %
Date: 2017-11-13 Branches: 15 44 34.1 %

Line Branch Exec Source
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/*	$OpenBSD: buf.c,v 1.27 2016/10/16 13:35:51 okan Exp $	*/
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/*
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 * Copyright (c) 2003 Jean-Francois Brousseau <jfb@openbsd.org>
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 * EXEMPLARY, OR CONSEQUENTIAL  DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <sys/queue.h>
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#include <sys/stat.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "buf.h"
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#include "xmalloc.h"
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#include "worklist.h"
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#define BUF_INCR	128
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struct buf {
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	/* buffer handle, buffer size, and data length */
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	u_char	*cb_buf;
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	size_t	 cb_size;
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	size_t	 cb_len;
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};
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#define SIZE_LEFT(b)	(b->cb_size - b->cb_len)
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static void	buf_grow(BUF *, size_t);
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/*
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 * Create a new buffer structure and return a pointer to it.  This structure
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 * uses dynamically-allocated memory and must be freed with buf_free(), once
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 * the buffer is no longer needed.
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 */
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BUF *
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buf_alloc(size_t len)
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{
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	BUF *b;
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	b = xmalloc(sizeof(*b));
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	/* Postpone creation of zero-sized buffers */
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	if (len > 0)
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		b->cb_buf = xcalloc(1, len);
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	else
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		b->cb_buf = NULL;
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	b->cb_size = len;
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	b->cb_len = 0;
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	return (b);
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}
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/*
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 * Open the file specified by <path> and load all of its contents into a
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 * buffer.
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 * Returns the loaded buffer on success or NULL on failure.
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 * Sets errno on error.
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 */
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BUF *
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buf_load(const char *path)
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{
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	int fd;
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	ssize_t ret;
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	size_t len;
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	u_char *bp;
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	struct stat st;
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	BUF *buf;
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	buf = NULL;
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	if ((fd = open(path, O_RDONLY, 0600)) == -1)
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		goto out;
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	if (fstat(fd, &st) == -1)
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		goto out;
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	if ((uintmax_t)st.st_size > SIZE_MAX) {
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		errno = EFBIG;
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		goto out;
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	}
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	buf = buf_alloc(st.st_size);
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	for (bp = buf->cb_buf; ; bp += (size_t)ret) {
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		len = SIZE_LEFT(buf);
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		ret = read(fd, bp, len);
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		if (ret == -1) {
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			int saved_errno;
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			saved_errno = errno;
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			buf_free(buf);
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			buf = NULL;
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			errno = saved_errno;
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			goto out;
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		} else if (ret == 0)
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			break;
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		buf->cb_len += (size_t)ret;
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	}
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out:
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	if (fd != -1) {
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		int saved_errno;
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		/* We may want to preserve errno here. */
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		saved_errno = errno;
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		(void)close(fd);
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		errno = saved_errno;
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	}
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	return (buf);
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}
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void
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buf_free(BUF *b)
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{
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	if (b == NULL)
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		return;
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	free(b->cb_buf);
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	free(b);
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}
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/*
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 * Free the buffer <b>'s structural information but do not free the contents
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 * of the buffer.  Instead, they are returned and should be freed later using
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 * free().
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 */
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void *
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buf_release(BUF *b)
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{
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	void *tmp;
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	tmp = b->cb_buf;
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	free(b);
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	return (tmp);
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}
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u_char *
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buf_get(BUF *b)
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{
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	return (b->cb_buf);
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}
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/*
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 * Empty the contents of the buffer <b> and reset pointers.
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 */
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void
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buf_empty(BUF *b)
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{
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	memset(b->cb_buf, 0, b->cb_size);
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	b->cb_len = 0;
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}
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/*
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 * Append a single character <c> to the end of the buffer <b>.
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 */
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void
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buf_putc(BUF *b, int c)
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{
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	u_char *bp;
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	if (SIZE_LEFT(b) == 0)
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		buf_grow(b, BUF_INCR);
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	bp = b->cb_buf + b->cb_len;
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	*bp = (u_char)c;
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	b->cb_len++;
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}
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/*
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 * Append a string <s> to the end of buffer <b>.
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 */
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void
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buf_puts(BUF *b, const char *str)
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{
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	buf_append(b, str, strlen(str));
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}
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/*
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 * Return u_char at buffer position <pos>.
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 */
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u_char
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buf_getc(BUF *b, size_t pos)
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{
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	return (b->cb_buf[pos]);
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}
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/*
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 * Append <len> bytes of data pointed to by <data> to the buffer <b>.  If the
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 * buffer is too small to accept all data, it will get resized to an
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 * appropriate size to accept all data.
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 * Returns the number of bytes successfully appended to the buffer.
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 */
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size_t
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buf_append(BUF *b, const void *data, size_t len)
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{
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	size_t left, rlen;
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	u_char *bp;
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	left = SIZE_LEFT(b);
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	rlen = len;
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	if (left < len)
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		buf_grow(b, len - left);
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	bp = b->cb_buf + b->cb_len;
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	memcpy(bp, data, rlen);
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	b->cb_len += rlen;
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	return (rlen);
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}
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/*
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 * Returns the size of the buffer that is being used.
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 */
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size_t
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buf_len(BUF *b)
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{
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	return (b->cb_len);
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}
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/*
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 * Write the contents of the buffer <b> to the specified <fd>
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 */
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int
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buf_write_fd(BUF *b, int fd)
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{
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	u_char *bp;
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	size_t len;
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	ssize_t ret;
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	len = b->cb_len;
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	bp = b->cb_buf;
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	do {
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		ret = write(fd, bp, len);
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		if (ret == -1) {
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			if (errno == EINTR || errno == EAGAIN)
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				continue;
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			return (-1);
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		}
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		len -= (size_t)ret;
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		bp += (size_t)ret;
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	} while (len > 0);
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	return (0);
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}
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/*
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 * Write the contents of the buffer <b> to the file whose path is given in
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 * <path>.  If the file does not exist, it is created with mode <mode>.
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 */
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int
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buf_write(BUF *b, const char *path, mode_t mode)
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{
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	int fd;
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 open:
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	if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
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		if (errno == EACCES && unlink(path) != -1)
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			goto open;
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		else
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			err(1, "%s", path);
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	}
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	if (buf_write_fd(b, fd) == -1) {
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		(void)unlink(path);
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		errx(1, "buf_write: buf_write_fd: `%s'", path);
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	}
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	if (fchmod(fd, mode) < 0)
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		warn("permissions not set on file %s", path);
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	(void)close(fd);
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	return (0);
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}
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/*
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 * Write the contents of the buffer <b> to a temporary file whose path is
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 * specified using <template> (see mkstemp.3).
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 * NB. This function will modify <template>, as per mkstemp
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 */
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void
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buf_write_stmp(BUF *b, char *template)
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{
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	int fd;
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	if ((fd = mkstemp(template)) == -1)
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		err(1, "%s", template);
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	worklist_add(template, &temp_files);
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	if (buf_write_fd(b, fd) == -1) {
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		(void)unlink(template);
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		errx(1, "buf_write_stmp: buf_write_fd: `%s'", template);
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	}
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	(void)close(fd);
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}
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/*
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 * Grow the buffer <b> by <len> bytes.  The contents are unchanged by this
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 * operation regardless of the result.
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 */
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static void
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buf_grow(BUF *b, size_t len)
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{
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	b->cb_buf = xreallocarray(b->cb_buf, 1, b->cb_size + len);
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	b->cb_size += len;
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}