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/*
* Off-the-Record Messaging Toolkit
* Copyright (C) 2004-2012 Ian Goldberg, Chris Alexander, Nikita Borisov
* <otr@cypherpunks.ca>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* system headers */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
char *data;
size_t len;
size_t alloclen;
} Buffer;
static void buf_new(Buffer *bufp)
{
bufp->data = NULL;
bufp->len = 0;
bufp->alloclen = 0;
}
static void buf_put(Buffer *bufp, const char *str, size_t len)
{
while (bufp->len + len + 1 > bufp->alloclen) {
char *newdata = realloc(bufp->data, bufp->alloclen + 1024);
if (!newdata) {
fprintf(stderr, "Out of memory!\n");
exit(1);
}
bufp->data = newdata;
bufp->alloclen += 1024;
}
memmove(bufp->data + bufp->len, str, len);
bufp->len += len;
bufp->data[bufp->len] = '\0';
}
static void buf_putc(Buffer *bufp, char c)
{
buf_put(bufp, &c, 1);
}
/* Read from the given stream until we see a complete OTR Key Exchange
* or OTR Data message. Return a newly-allocated pointer to a copy of
* this message, which the caller should free(). Returns NULL if no
* such message could be found. */
char *readotr(FILE *stream)
{
int seen = 0;
const char header[] = "?OTR:"; /* There are no '?' chars other than
the leading one */
int headerlen = strlen(header);
Buffer buf;
while(seen < headerlen) {
int c = fgetc(stream);
if (c == EOF) return NULL;
else if (c == header[seen]) seen++;
else if (c == header[0]) seen = 1;
else seen = 0;
}
buf_new(&buf);
buf_put(&buf, header, headerlen);
/* Look for the trailing '.' */
while(1) {
int c = fgetc(stream);
if (c == EOF) break;
buf_putc(&buf, c);
if (c == '.') break;
}
return buf.data;
}