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116 lines
2.8 KiB
116 lines
2.8 KiB
/*
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* The Qubes OS Project, http://www.qubes-os.org
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*
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* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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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 "libqrexec-utils.h"
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#define BUFFER_LIMIT 50000000
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static int total_mem;
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static char *limited_malloc(int len)
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{
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char *ret;
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total_mem += len;
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if (total_mem > BUFFER_LIMIT) {
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fprintf(stderr, "attempt to allocate >BUFFER_LIMIT\n");
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exit(1);
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}
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ret = malloc(len);
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if (!ret) {
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perror("malloc");
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exit(1);
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}
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return ret;
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}
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static void limited_free(char *ptr, int len)
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{
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free(ptr);
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total_mem -= len;
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}
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void buffer_init(struct buffer *b)
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{
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b->buflen = 0;
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b->data = NULL;
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}
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void buffer_free(struct buffer *b)
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{
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if (b->buflen)
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limited_free(b->data, b->buflen);
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buffer_init(b);
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}
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/*
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The following two functions can be made much more efficient.
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Yet the profiling output show they are not significant CPU hogs, so
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we keep them so simple to make them obviously correct.
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*/
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void buffer_append(struct buffer *b, const char *data, int len)
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{
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int newsize;
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char *qdata;
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if (len < 0 || len > BUFFER_LIMIT) {
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fprintf(stderr, "buffer_append %d\n", len);
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exit(1);
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}
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if (len == 0)
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return;
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newsize = len + b->buflen;
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qdata = limited_malloc(len + b->buflen);
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memcpy(qdata, b->data, b->buflen);
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memcpy(qdata + b->buflen, data, len);
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buffer_free(b);
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b->buflen = newsize;
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b->data = qdata;
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}
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void buffer_remove(struct buffer *b, int len)
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{
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int newsize;
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char *qdata = NULL;
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if (len < 0 || len > b->buflen) {
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fprintf(stderr, "buffer_remove %d/%d\n", len, b->buflen);
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exit(1);
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}
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newsize = b->buflen - len;
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if (newsize > 0) {
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qdata = limited_malloc(newsize);
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memcpy(qdata, b->data + len, newsize);
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}
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buffer_free(b);
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b->buflen = newsize;
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b->data = qdata;
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}
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int buffer_len(struct buffer *b)
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{
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return b->buflen;
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}
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void *buffer_data(struct buffer *b)
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{
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return b->data;
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}
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