logbuf.c

/*-
 * SSLsplit - transparent SSL/TLS interception
 * https://www.roe.ch/SSLsplit
 *
 * Copyright (c) 2009-2018, Daniel Roethlisberger <daniel@roe.ch>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "logbuf.h"

#include <stdarg.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>

/*
 * Dynamic log buffer with zero-copy chaining, generic void * file handle
 * and ctl for status control flags.
 * Logbuf always owns the internal allocated buffer.
 */

/*
 * Create new logbuf from provided, pre-allocated buffer, set fd and next.
 * The provided buffer will be freed by logbuf_free() if non-NULL, and by
 * logbuf_new() in case it fails returning NULL.
 */
logbuf_t *
logbuf_new(void *buf, size_t sz, logbuf_t *next)
{
	logbuf_t *lb;

	if (!(lb = malloc(sizeof(logbuf_t)))) {
		if (buf)
			free(buf);
		return NULL;
	}
	lb->buf = buf;
	lb->sz = sz;
	if (next) {
		lb->fh = next->fh;
		lb->ctl = next->ctl;
		lb->next = next;
	} else {
		lb->fh = NULL;
		lb->ctl = 0;
		lb->next = NULL;
	}
	return lb;
}

/*
 * Create new logbuf, allocating sz bytes into the internal buffer.
 */
logbuf_t *
logbuf_new_alloc(size_t sz, logbuf_t *next)
{
	logbuf_t *lb;

	if (!(lb = malloc(sizeof(logbuf_t))))
		return NULL;
	if (!(lb->buf = malloc(sz))) {
		free(lb);
		return NULL;
	}
	lb->sz = sz;
	if (next) {
		lb->fh = next->fh;
		lb->ctl = next->ctl;
		lb->next = next;
	} else {
		lb->fh = NULL;
		lb->ctl = 0;
		lb->next = NULL;
	}
	return lb;
}

/*
 * Create new logbuf, copying buf into a newly allocated internal buffer.
 */
logbuf_t *
logbuf_new_copy(const void *buf, size_t sz, logbuf_t *next)
{
	logbuf_t *lb;

	if (!(lb = malloc(sizeof(logbuf_t))))
		return NULL;
	if (!(lb->buf = malloc(sz))) {
		free(lb);
		return NULL;
	}
	memcpy(lb->buf, buf, sz);
	lb->sz = sz;
	if (next) {
		lb->fh = next->fh;
		lb->ctl = next->ctl;
		lb->next = next;
	} else {
		lb->fh = NULL;
		lb->ctl = 0;
		lb->next = NULL;
	}
	return lb;
}

/*
 * Create new logbuf using printf.
 */
logbuf_t *
logbuf_new_printf(logbuf_t *next, const char *fmt, ...)
{
	va_list ap;
	logbuf_t *lb;

	if (!(lb = malloc(sizeof(logbuf_t))))
		return NULL;
	va_start(ap, fmt);
	lb->sz = vasprintf((char**)&lb->buf, fmt, ap);
	va_end(ap);
	if (lb->sz < 0) {
		free(lb);
		return NULL;
	}
	if (next) {
		lb->fh = next->fh;
		lb->ctl = next->ctl;
		lb->next = next;
	} else {
		lb->fh = NULL;
		lb->ctl = 0;
		lb->next = NULL;
	}
	return lb;
}

/*
 * Create new logbuf from lb.  If combine is set, combine all the buffer
 * segments into a single contiguous one.  Otherwise, copy segment by segment.
 */
logbuf_t *
logbuf_new_deepcopy(logbuf_t *lb, int combine)
{
	logbuf_t *lbnew;
	unsigned char *p;

	if (!lb)
		return NULL;

	if (combine) {
		lbnew = logbuf_new_alloc(logbuf_size(lb), NULL);
		if (!lbnew)
			return NULL;
		lbnew->fh = lb->fh;
		lbnew->ctl = lb->ctl;
		p = lbnew->buf;
		while (lb) {
			memcpy(p, lb->buf, lb->sz);
			p += lb->sz;
			lb = lb->next;
		}
	} else {
		lbnew = logbuf_new_copy(lb->buf, lb->sz, NULL);
		if (!lbnew)
			return NULL;
		lbnew->fh = lb->fh;
		lbnew->ctl = lb->ctl;
		lbnew->next = logbuf_new_deepcopy(lb->next, 0);
	}
	return lbnew;
}

logbuf_t *
logbuf_make_contiguous(logbuf_t *lb) {
	unsigned char *p;
	logbuf_t *lbtmp;

	if (!lb)
		return NULL;
	if (!lb->next)
		return lb;
	p = realloc(lb->buf, logbuf_size(lb));
	if (!p)
		return NULL;
	lb->buf = p;
	lbtmp = lb;
	p += lbtmp->sz;
	while ((lbtmp = lbtmp->next)) {
		memcpy(p, lbtmp->buf, lbtmp->sz);
		lb->sz += lbtmp->sz;
		p += lbtmp->sz;
	}
	logbuf_free(lb->next);
	lb->next = NULL;
	return lb;
}

/*
 * Calculate the total size of the logbuf and all chained buffers.
 */
ssize_t
logbuf_size(logbuf_t *lb)
{
	ssize_t sz;

	sz = lb->sz;
	if (lb->next) {
		sz += logbuf_size(lb->next);
	}
	return sz;
}

/*
 * Write content of logbuf using writefunc and free all buffers.
 * Returns -1 on errors and sets errno according to write().
 * Returns total of bytes written by 1 .. n write() calls on success.
 */
ssize_t
logbuf_write_free(logbuf_t *lb, writefunc_t writefunc)
{
	ssize_t rv1, rv2 = 0;
	rv1 = writefunc(lb->fh, lb->ctl, lb->buf, lb->sz);
	if (lb->buf) {
		free(lb->buf);
	}
	if (lb->next) {
		if (rv1 == -1) {
			logbuf_free(lb->next);
		} else {
			lb->next->fh = lb->fh;
			rv2 = logbuf_write_free(lb->next, writefunc);
		}
	}
	free(lb);
	if (rv1 == -1 || rv2 == -1)
		return -1;
	else
		return rv1 + rv2;
}

/*
 * Free logbuf including internal and chained buffers.
 */
void
logbuf_free(logbuf_t *lb)
{
	if (lb->buf) {
		free(lb->buf);
	}
	if (lb->next) {
		logbuf_free(lb->next);
	}
	free(lb);
}

/* vim: set noet ft=c: */