GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.sbin/syslogd/ringbuf.c Lines: 0 50 0.0 %
Date: 2017-11-07 Branches: 0 32 0.0 %

Line Branch Exec Source
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/* $OpenBSD: ringbuf.c,v 1.10 2016/10/16 22:12:50 bluhm Exp $ */
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/*
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 * Copyright (c) 2004 Damien Miller
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 *
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 * Permission to use, copy, modify, and distribute this software for any
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 * purpose with or without fee is hereby granted, provided that the above
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 * copyright notice and this permission notice appear in all copies.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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 */
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/*
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 * Simple ringbuffer for lines of text.
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 */
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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 "syslogd.h"
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#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
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/* Initialise a ring buffer */
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struct ringbuf *
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ringbuf_init(size_t len)
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{
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	struct ringbuf *ret;
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	if (len == 0 || (ret = malloc(sizeof(*ret))) == NULL)
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		return (NULL);
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	if ((ret->buf = malloc(len)) == NULL) {
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		free(ret);
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		return (NULL);
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	}
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	ret->len = len;
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	ret->start = ret->end = 0;
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	return (ret);
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}
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/* Free a ring buffer */
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void
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ringbuf_free(struct ringbuf *rb)
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{
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	free(rb->buf);
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	free(rb);
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}
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/* Clear a ring buffer */
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void
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ringbuf_clear(struct ringbuf *rb)
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{
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	rb->start = rb->end = 0;
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}
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/* Return the number of bytes used in a ringbuffer */
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size_t
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ringbuf_used(struct ringbuf *rb)
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{
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	return ((rb->len + rb->end - rb->start) % rb->len);
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}
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/*
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 * Append a line to a ring buffer, will delete lines from start
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 * of buffer as necessary
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 */
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int
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ringbuf_append_line(struct ringbuf *rb, char *line)
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{
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	size_t llen, used, copy_len;
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	int overflow = 0;
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	if (rb == NULL || line == NULL)
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		return (-1);
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	llen = strlen(line);
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	if (llen == 0)
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		return (-1);
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	if (line[llen - 1] != '\n')
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		llen++; /* one extra for appended '\n' */
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	if (llen >= rb->len)
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		return (-1);
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	/*
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	 * If necessary, advance start pointer to make room for appended
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	 * string. Ensure that start pointer is at the beginning of a line
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	 * once we are done (i.e move to after '\n').
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	 */
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	used = ringbuf_used(rb);
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	if (used + llen >= rb->len) {
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		rb->start = (rb->start + used + llen - rb->len) % rb->len;
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		/* Find next '\n' */
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		while (rb->buf[rb->start] != '\n')
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			rb->start = (rb->start + 1) % rb->len;
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		/* Skip it */
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		rb->start = (rb->start + 1) % rb->len;
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		overflow = 1;
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	}
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	/*
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	 * Now append string, starting from last pointer and wrapping if
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	 * necessary
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	 */
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	if (rb->end + llen > rb->len) {
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		copy_len = rb->len - rb->end;
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		memcpy(rb->buf + rb->end, line, copy_len);
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		memcpy(rb->buf, line + copy_len, llen - copy_len - 1);
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		rb->buf[llen - copy_len - 1] = '\n';
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	} else {
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		memcpy(rb->buf + rb->end, line, llen - 1);
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		rb->buf[rb->end + llen - 1] = '\n';
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	}
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	rb->end = (rb->end + llen) % rb->len;
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	return (overflow);
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}
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/*
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 * Copy and nul-terminate a ringbuffer to a string.
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 */
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ssize_t
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ringbuf_to_string(char *buf, size_t len, struct ringbuf *rb)
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{
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	size_t copy_len, n;
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	if (buf == NULL || rb == NULL || len == 0)
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		return (-1);
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	copy_len = MINIMUM(len - 1, ringbuf_used(rb));
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	if (copy_len == 0)
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		return (copy_len);
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	if (rb->start < rb->end)
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		memcpy(buf, rb->buf + rb->start, copy_len);
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	else {
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		/* If the buffer is wrapped, copy each hunk separately */
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		n = rb->len - rb->start;
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		memcpy(buf, rb->buf + rb->start, MINIMUM(n, copy_len));
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		if (copy_len > n)
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			memcpy(buf + n, rb->buf,
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			    MINIMUM(rb->end, copy_len - n));
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	}
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	buf[copy_len] = '\0';
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	return (ringbuf_used(rb));
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}