construct/libcharybdis/linebuf.c

/*
 *  ircd-ratbox: A slightly useful ircd.
 *  linebuf.c: Maintains linebuffers.
 *
 *  Copyright (C) 2001-2002 Adrian Chadd <adrian@creative.net.au>
 *  Copyright (C) 2002 Hybrid Development Team
 *  Copyright (C) 2002-2005 ircd-ratbox development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 *  $Id: linebuf.c 1110 2006-03-29 22:55:25Z nenolod $
 */

#include "stdinc.h"
#include "tools.h"
#include "client.h"
#include "linebuf.h"
#include "memory.h"
#include "event.h"
#include "balloc.h"
#include "hook.h"
#include "commio.h"
#include "sprintf_irc.h"

#ifdef STRING_WITH_STRINGS
# include <string.h>
# include <strings.h>
#else
# ifdef HAVE_STRING_H
#  include <string.h>
# else
#  ifdef HAVE_STRINGS_H
#   include <strings.h>
#  endif
# endif
#endif

extern BlockHeap *linebuf_heap;

static int bufline_count = 0;


/*
 * linebuf_init
 *
 * Initialise the linebuf mechanism
 */


void
linebuf_init(void)
{
	linebuf_heap = BlockHeapCreate(sizeof(buf_line_t), LINEBUF_HEAP_SIZE);
}

static buf_line_t *
linebuf_allocate(void)
{
	buf_line_t *t;
	t = BlockHeapAlloc(linebuf_heap);
	t->refcount = 0;
	return (t);

}

static void
linebuf_free(buf_line_t * p)
{
	BlockHeapFree(linebuf_heap, p);
}

/*
 * linebuf_new_line
 *
 * Create a new line, and link it to the given linebuf.
 * It will be initially empty.
 */
static buf_line_t *
linebuf_new_line(buf_head_t * bufhead)
{
	buf_line_t *bufline;
	dlink_node *node;

	bufline = linebuf_allocate();
	if(bufline == NULL)
		return NULL;
	++bufline_count;


	node = make_dlink_node();

	bufline->len = 0;
	bufline->terminated = 0;
	bufline->flushing = 0;
	bufline->raw = 0;

	/* Stick it at the end of the buf list */
	dlinkAddTail(bufline, node, &bufhead->list);
	bufline->refcount++;

	/* And finally, update the allocated size */
	bufhead->alloclen++;
	bufhead->numlines++;

	return bufline;
}


/*
 * linebuf_done_line
 *
 * We've finished with the given line, so deallocate it
 */
static void
linebuf_done_line(buf_head_t * bufhead, buf_line_t * bufline, dlink_node * node)
{
	/* Remove it from the linked list */
	dlinkDestroy(node, &bufhead->list);

	/* Update the allocated size */
	bufhead->alloclen--;
	bufhead->len -= bufline->len;
	s_assert(bufhead->len >= 0);
	bufhead->numlines--;

	bufline->refcount--;
	s_assert(bufline->refcount >= 0);

	if(bufline->refcount == 0)
	{
		/* and finally, deallocate the buf */
		--bufline_count;
		s_assert(bufline_count >= 0);
		linebuf_free(bufline);
	}
}


/*
 * skip to end of line or the crlfs, return the number of bytes ..
 */
static inline int
linebuf_skip_crlf(char *ch, int len)
{
	int orig_len = len;

	/* First, skip until the first non-CRLF */
	for (; len; len--, ch++)
	{
		if(*ch == '\r')
			break;
		else if(*ch == '\n')
			break;
	}

	/* Then, skip until the last CRLF */
	for (; len; len--, ch++)
	{
		if((*ch != '\r') && (*ch != '\n'))
			break;
	}
	s_assert(orig_len > len);
	return (orig_len - len);
}



/*
 * linebuf_newbuf
 *
 * Initialise the new buffer
 */
void
linebuf_newbuf(buf_head_t * bufhead)
{
	/* not much to do right now :) */
	memset(bufhead, 0, sizeof(buf_head_t));
}

/*
 * client_flush_input
 *
 * inputs	- pointer to client
 * output	- none
 * side effects - all input line bufs are flushed 
 */
void
client_flush_input(struct Client *client_p)
{
	/* This way, it can be called for remote client as well */

	if(client_p->localClient == NULL)
		return;

	linebuf_donebuf(&client_p->localClient->buf_recvq);
}


/*
 * linebuf_donebuf
 *
 * Flush all the lines associated with this buffer
 */
void
linebuf_donebuf(buf_head_t * bufhead)
{
	while (bufhead->list.head != NULL)
	{
		linebuf_done_line(bufhead,
				  (buf_line_t *) bufhead->list.head->data, bufhead->list.head);
	}
}

/*
 * linebuf_copy_line
 *
 * Okay..this functions comments made absolutely no sense.
 * 
 * Basically what we do is this.  Find the first chunk of text
 * and then scan for a CRLF.  If we didn't find it, but we didn't
 * overflow our buffer..we wait for some more data.
 * If we found a CRLF, we replace them with a \0 character.
 * If we overflowed, we copy the most our buffer can handle, terminate
 * it with a \0 and return.
 *
 * The return value is the amount of data we consumed.  This could
 * be different than the size of the linebuffer, as when we discard
 * the overflow, we don't want to process it again.
 *
 * This still sucks in my opinion, but it seems to work.
 *
 * -Aaron
 */
static int
linebuf_copy_line(buf_head_t * bufhead, buf_line_t * bufline, char *data, int len)
{
	int cpylen = 0;		/* how many bytes we've copied */
	char *ch = data;	/* Pointer to where we are in the read data */
	char *bufch = bufline->buf + bufline->len;
	int clen = 0;		/* how many bytes we've processed,
				   and don't ever want to see again.. */

	/* If its full or terminated, ignore it */

	bufline->raw = 0;
	s_assert(bufline->len < BUF_DATA_SIZE);
	if(bufline->terminated == 1)
		return 0;

	clen = cpylen = linebuf_skip_crlf(ch, len);
	if(clen == -1)
		return -1;

	/* This is the ~overflow case..This doesn't happen often.. */
	if(cpylen > (BUF_DATA_SIZE - bufline->len - 1))
	{
		memcpy(bufch, ch, (BUF_DATA_SIZE - bufline->len - 1));
		bufline->buf[BUF_DATA_SIZE - 1] = '\0';
		bufch = bufline->buf + BUF_DATA_SIZE - 2;
		while (cpylen && (*bufch == '\r' || *bufch == '\n'))
		{
			*bufch = '\0';
			cpylen--;
			bufch--;
		}
		bufline->terminated = 1;
		bufline->len = BUF_DATA_SIZE - 1;
		bufhead->len += BUF_DATA_SIZE - 1;
		return clen;
	}

	memcpy(bufch, ch, cpylen);
	bufch += cpylen;
	*bufch = '\0';
	bufch--;

	if(*bufch != '\r' && *bufch != '\n')
	{
		/* No linefeed, bail for the next time */
		bufhead->len += cpylen;
		bufline->len += cpylen;
		bufline->terminated = 0;
		return clen;
	}

	/* Yank the CRLF off this, replace with a \0 */
	while (cpylen && (*bufch == '\r' || *bufch == '\n'))
	{
		*bufch = '\0';
		cpylen--;
		bufch--;
	}

	bufline->terminated = 1;
	bufhead->len += cpylen;
	bufline->len += cpylen;
	return clen;
}

/*
 * linebuf_copy_raw
 *
 * Copy as much data as possible directly into a linebuf,
 * splitting at \r\n, but without altering any data.
 *
 */
static int
linebuf_copy_raw(buf_head_t * bufhead, buf_line_t * bufline, char *data, int len)
{
	int cpylen = 0;		/* how many bytes we've copied */
	char *ch = data;	/* Pointer to where we are in the read data */
	char *bufch = bufline->buf + bufline->len;
	int clen = 0;		/* how many bytes we've processed,
				   and don't ever want to see again.. */

	/* If its full or terminated, ignore it */

	bufline->raw = 1;
	s_assert(bufline->len < BUF_DATA_SIZE);
	if(bufline->terminated == 1)
		return 0;

	clen = cpylen = linebuf_skip_crlf(ch, len);
	if(clen == -1)
		return -1;

	/* This is the overflow case..This doesn't happen often.. */
	if(cpylen > (BUF_DATA_SIZE - bufline->len - 1))
	{
		clen = BUF_DATA_SIZE - bufline->len - 1;
		memcpy(bufch, ch, clen);
		bufline->buf[BUF_DATA_SIZE - 1] = '\0';
		bufch = bufline->buf + BUF_DATA_SIZE - 2;
		bufline->terminated = 1;
		bufline->len = BUF_DATA_SIZE - 1;
		bufhead->len += BUF_DATA_SIZE - 1;
		return clen;
	}

	memcpy(bufch, ch, cpylen);
	bufch += cpylen;
	*bufch = '\0';
	bufch--;

	if(*bufch != '\r' && *bufch != '\n')
	{
		/* No linefeed, bail for the next time */
		bufhead->len += cpylen;
		bufline->len += cpylen;
		bufline->terminated = 0;
		return clen;
	}

	bufline->terminated = 1;
	bufhead->len += cpylen;
	bufline->len += cpylen;
	return clen;
}


/*
 * linebuf_parse
 *
 * Take a given buffer and break out as many buffers as we can.
 * If we find a CRLF, we terminate that buffer and create a new one.
 * If we don't find a CRLF whilst parsing a buffer, we don't mark it
 * 'finished', so the next loop through we can continue appending ..
 *
 * A few notes here, which you'll need to understand before continuing.
 *
 * - right now I'm only dealing with single sized buffers. Later on,
 *   I might consider chaining buffers together to get longer "lines"
 *   but seriously, I don't see the advantage right now.
 *
 * - This *is* designed to turn into a reference-counter-protected setup
 *   to dodge copious copies.
 */
int
linebuf_parse(buf_head_t * bufhead, char *data, int len, int raw)
{
	buf_line_t *bufline;
	int cpylen;
	int linecnt = 0;

	/* First, if we have a partial buffer, try to squeze data into it */
	if(bufhead->list.tail != NULL)
	{
		/* Check we're doing the partial buffer thing */
		bufline = bufhead->list.tail->data;
		s_assert(!bufline->flushing);
		/* just try, the worst it could do is *reject* us .. */
		if(!raw)
			cpylen = linebuf_copy_line(bufhead, bufline, data, len);
		else
			cpylen = linebuf_copy_raw(bufhead, bufline, data, len);
			
		if(cpylen == -1)
			return -1;

		linecnt++;
		/* If we've copied the same as what we've got, quit now */
		if(cpylen == len)
			return linecnt;	/* all the data done so soon? */

		/* Skip the data and update len .. */
		len -= cpylen;
		s_assert(len >= 0);
		data += cpylen;
	}

	/* Next, the loop */
	while (len > 0)
	{
		/* We obviously need a new buffer, so .. */
		bufline = linebuf_new_line(bufhead);

		/* And parse */
		if(!raw)
			cpylen = linebuf_copy_line(bufhead, bufline, data, len);
		else
			cpylen = linebuf_copy_raw(bufhead, bufline, data, len);
		
		if(cpylen == -1)
			return -1;

		len -= cpylen;
		s_assert(len >= 0);
		data += cpylen;
		linecnt++;
	}
	return linecnt;
}


/*
 * linebuf_get
 *
 * get the next buffer from our line. For the time being it will copy
 * data into the given buffer and free the underlying linebuf.
 */
int
linebuf_get(buf_head_t * bufhead, char *buf, int buflen, int partial, int raw)
{
	buf_line_t *bufline;
	int cpylen;
	char *start, *ch;

	/* make sure we have a line */
	if(bufhead->list.head == NULL)
		return 0;	/* Obviously not.. hrm. */

	bufline = bufhead->list.head->data;

	/* make sure that the buffer was actually *terminated */
	if(!(partial || bufline->terminated))
		return 0;	/* Wait for more data! */

	/* make sure we've got the space, including the NULL */
	cpylen = bufline->len;
	s_assert(cpylen + 1 <= buflen);

	/* Copy it */
	start = bufline->buf;

	/* if we left extraneous '\r\n' characters in the string,
	 * and we don't want to read the raw data, clean up the string.
	 */
	if(bufline->raw && !raw)
	{
		/* skip leading EOL characters */
		while (cpylen && (*start == '\r' || *start == '\n'))
		{
			start++;
			cpylen--;
		}
		/* skip trailing EOL characters */
		ch = &start[cpylen - 1];
		while (cpylen && (*ch == '\r' || *ch == '\n'))
		{
			ch--;
			cpylen--;
		}
	}
	memcpy(buf, start, cpylen + 1);

	/* convert CR/LF to NULL */
	if(bufline->raw && !raw)
		buf[cpylen] = '\0';

	s_assert(cpylen >= 0);

	/* Deallocate the line */
	linebuf_done_line(bufhead, bufline, bufhead->list.head);

	/* return how much we copied */
	return cpylen;
}

/*
 * linebuf_attach
 *
 * attach the lines in a buf_head_t to another buf_head_t
 * without copying the data (using refcounts).
 */
void
linebuf_attach(buf_head_t * bufhead, buf_head_t * new)
{
	dlink_node *ptr;
	buf_line_t *line;

	DLINK_FOREACH(ptr, new->list.head)
	{
		line = ptr->data;
		dlinkAddTailAlloc(line, &bufhead->list);

		/* Update the allocated size */
		bufhead->alloclen++;
		bufhead->len += line->len;
		bufhead->numlines++;

		line->refcount++;
	}
}

/*
 * linebuf_putmsg
 *
 * Similar to linebuf_put, but designed for use by send.c.
 *
 * prefixfmt is used as a format for the varargs, and is inserted first.
 * Then format/va_args is appended to the buffer.
 */
void
linebuf_putmsg(buf_head_t * bufhead, const char *format, va_list * va_args,
	       const char *prefixfmt, ...)
{
	buf_line_t *bufline;
	int len = 0;
	va_list prefix_args;

	/* make sure the previous line is terminated */
#ifndef NDEBUG
	if(bufhead->list.tail)
	{
		bufline = bufhead->list.tail->data;
		s_assert(bufline->terminated);
	}
#endif
	/* Create a new line */
	bufline = linebuf_new_line(bufhead);

	if(prefixfmt != NULL)
	{
		va_start(prefix_args, prefixfmt);
		len = ircvsnprintf(bufline->buf, BUF_DATA_SIZE, prefixfmt, prefix_args);
		va_end(prefix_args);
	}

	if(va_args != NULL)
	{
		len += ircvsnprintf((bufline->buf + len), (BUF_DATA_SIZE - len), format, *va_args);
	}

	bufline->terminated = 1;

	/* Truncate the data if required */
	if(len > 510)
	{
		len = 510;
		bufline->buf[len++] = '\r';
		bufline->buf[len++] = '\n';
	}
	else if(len == 0)
	{
		bufline->buf[len++] = '\r';
		bufline->buf[len++] = '\n';
		bufline->buf[len] = '\0';
	}
	else
	{
		/* Chop trailing CRLF's .. */
		while ((bufline->buf[len] == '\r')
		       || (bufline->buf[len] == '\n') || (bufline->buf[len] == '\0'))
		{
			len--;
		}

		bufline->buf[++len] = '\r';
		bufline->buf[++len] = '\n';
		bufline->buf[++len] = '\0';
	}

	bufline->len = len;
	bufhead->len += len;
}



/*
 * linebuf_flush
 *
 * Flush data to the buffer. It tries to write as much data as possible
 * to the given socket. Any return values are passed straight through.
 * If there is no data in the socket, EWOULDBLOCK is set as an errno
 * rather than returning 0 (which would map to an EOF..)
 *
 * Notes: XXX We *should* have a clue here when a non-full buffer is arrived.
 *        and tag it so that we don't re-schedule another write until
 *        we have a CRLF.
 */

int
linebuf_flush(int fd, buf_head_t * bufhead)
{
	buf_line_t *bufline;
	int retval;
	/* Check we actually have a first buffer */
	if(bufhead->list.head == NULL)
	{
		/* nope, so we return none .. */
		errno = EWOULDBLOCK;
		return -1;
	}

	bufline = bufhead->list.head->data;

	/* And that its actually full .. */
	if(!bufline->terminated)
	{
		errno = EWOULDBLOCK;
		return -1;
	}

	/* Check we're flushing the first buffer */
	if(!bufline->flushing)
	{
		bufline->flushing = 1;
		bufhead->writeofs = 0;
	}

	/* Now, try writing data */
	retval = send(fd, bufline->buf + bufhead->writeofs, bufline->len - bufhead->writeofs, 0);

	if(retval <= 0)
		return retval;

	/* we've got data, so update the write offset */
	bufhead->writeofs += retval;

	/* if we've written everything *and* the CRLF, deallocate and update
	   bufhead */
	if(bufhead->writeofs == bufline->len)
	{
		bufhead->writeofs = 0;
		s_assert(bufhead->len >= 0);
		linebuf_done_line(bufhead, bufline, bufhead->list.head);
	}

	/* Return line length */
	return retval;
}



/*
 * count linebufs for stats z
 */

void
count_linebuf_memory(size_t * count, size_t * linebuf_memory_used)
{
	BlockHeapUsage(linebuf_heap, count, NULL, linebuf_memory_used);
}