// parse_peer(s, len)
// Parse a peer specification from the first 'len' characters of 's'.
// A peer specification looks like "PEER [alias] [addr]:[port]".
static peer_t *parse_peer(const char *s, size_t len)
{
peer_t *p = (peer_t *) malloc(sizeof(peer_t));
if (p) {
p->next = NULL;
if (osp2p_snscanf(s, len, "PEER %s %I:%d",
p->alias, &p->addr, &p->port) >= 0
&& p->port > 0 && p->port <= 65535)
return p;
}
free(p);
return NULL;
}
// task_upload(t)
// Handles an upload request from another peer.
// First reads the request into the task buffer, then serves the peer
// the requested file.
static void task_upload(task_t *t)
{
int blockno;
int namelen;
size_t offset;
assert(t->type == TASK_UPLOAD);
// First, read the request from the peer.
while (1) {
int ret = read_to_taskbuf(t->peer_fd, t);
if (ret == TBUF_ERROR) {
error("* Cannot read from connection");
goto exit;
} else if (ret == TBUF_END
|| (t->tail && t->buf[t->tail-1] == '\n'))
break;
}
//*************************************
//Exercise 2: prevent a peer from requesting an invalid file name
if(strlen(t->buf) > FILENAMESIZ + 10){
error("Error: file name requested by peer is too long\n");
goto exit;
}
assert(t->head == 0);
if (osp2p_snscanf(t->buf, t->tail, "GET %s OSP2P\n", t->filename) < 0) {
error("* Odd request %.*s\n", t->tail, t->buf);
goto exit;
}
namelen = strlen(t->filename);
blockno = t->filename[namelen-1] - '0';
t->filename[namelen-1] = 0;
t->head = t->tail = 0;
int i;
for(i = 0; i < FILENAMESIZ && t->filename[i] != 0; i++){
if(t->filename[i] == '/'){
error("Error: file requested by peer is not in current directory\n");
goto exit;
}
}
//*************************************************
if(evil_mode == 0){
t->disk_fd = open(t->filename, O_RDONLY);
if (t->disk_fd == -1) {
error("* Cannot open file %s", t->filename);
goto exit;
}
lseek(t->disk_fd, BLKSIZE, SEEK_CUR);
message("* Transferring file %s\n", t->filename);
// Now, read file from disk and write it to the requesting peer.
while (1) {
int ret = write_from_taskbuf(t->peer_fd, t);
if (ret == TBUF_ERROR) {
error("* Peer write error");
goto exit;
}
ret = read_to_taskbuf(t->disk_fd, t);
if (ret == TBUF_ERROR) {
error("* Disk read error");
goto exit;
} else if (ret == TBUF_END && t->head == t->tail)
/* End of file */
break;
}
}
else{
//***************************
//Exercise 3: send null device data to peer
t->disk_fd = open("/dev/null", O_RDONLY);
if (t->disk_fd == -1) {
error("* Cannot open file\n");
goto exit;
}
message("* Transferring file\n");
while (1) {
int ret = write_from_taskbuf(t->peer_fd, t);
if (ret == TBUF_ERROR) {
error("* Peer write error");
goto exit;
}
ret = read_to_taskbuf(t->disk_fd, t);
if (ret == TBUF_ERROR) {
error("* Disk read error");
goto exit;
}
}
//****************************
}
message("* Upload of %s complete\n", t->filename);
exit:
task_free(t);
}