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255 lines
4.9 KiB
C
255 lines
4.9 KiB
C
/*
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* comm.c - Fakefile IPC functions
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*
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* Copyright 2012 by Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <assert.h>
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#include <sys/types.h>
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#include "util.h"
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#include "comm.h"
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#define BUF_SIZE 4096
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struct fakefile_peer {
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int in, out;
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uint8_t buf[BUF_SIZE];
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void *pos;
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const void *end;
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};
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struct fakefile_msg {
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struct fakefile_peer *peer;
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void *buf; /* NULL if reading */
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void *pos; /* current position in buffer; write only */
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size_t len; /* amount of data read/written so far */
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size_t msg_size; /* declared size */
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size_t buf_size; /* allocated size; write only */
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};
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static int master_fd(const char *name)
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{
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const char *s;
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char *end;
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long n;
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s = getenv(name);
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if (!s) {
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fprintf(stderr, "%s not set\n", name);
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exit(1);
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}
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n = strtol(s, &end, 0);
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if (*end || n < 0) {
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fprintf(stderr, "invalid fd \"%s\" for %s\n", s, name);
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exit(1);
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}
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return n;
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}
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static struct fakefile_peer *sanitize_peer(struct fakefile_peer *peer)
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{
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static int have_peer = 0;
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static struct fakefile_peer master;
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if (peer)
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return peer;
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if (!have_peer) {
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master.in = master_fd(FAKEFILE_MASTER_OUT_VAR);
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master.out = master_fd(FAKEFILE_MASTER_IN_VAR);
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master.pos = master.buf;
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master.end = master.buf;
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have_peer = 1;
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}
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return &master;
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}
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struct fakefile_peer *fakefile_peer(int in, int out)
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{
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struct fakefile_peer *peer;
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peer = alloc_type(struct fakefile_peer);
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peer->in = in;
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peer->out = out;
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peer->pos = peer->buf;
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peer->end = peer->buf;
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return peer;
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}
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void fakefile_peer_close(struct fakefile_peer *peer)
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{
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(void) close(peer->in);
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(void) close(peer->out);
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free(peer);
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}
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int fakefile_peer_fd(const struct fakefile_peer *peer)
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{
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return peer->in;
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}
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struct fakefile_msg *fakefile_msg_new(struct fakefile_peer *peer, int size)
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{
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struct fakefile_msg *msg;
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size_t buf_size;
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size += sizeof(int);
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buf_size = size > BUF_SIZE ? BUF_SIZE : size;
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msg = alloc_size(sizeof(struct fakefile_msg)+buf_size);
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msg->peer = sanitize_peer(peer);
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msg->buf = msg->pos = msg+1;
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msg->len = 0;
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msg->msg_size = size;
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msg->buf_size = buf_size;
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fakefile_msg_add_int(msg, size);
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return msg;
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}
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static void flush_out(struct fakefile_msg *msg)
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{
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const void *p;
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ssize_t len;
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if (msg->pos == msg->buf)
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return;
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for (p = msg->buf; p != msg->pos; p += len) {
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len = write(msg->peer->out, p, msg->pos-p);
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if (len <= 0) {
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perror("fakefile IPC write");
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exit(1);
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}
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}
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}
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struct fakefile_msg *fakefile_msg_recv(struct fakefile_peer *peer)
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{
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struct fakefile_msg *msg;
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msg = alloc_type(struct fakefile_msg);
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msg->peer = sanitize_peer(peer);
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msg->buf = NULL;
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msg->len = 0;
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msg->msg_size = sizeof(int);
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msg->msg_size = fakefile_msg_get_int(msg);
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return msg;
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}
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void fakefile_msg_end(struct fakefile_msg *msg)
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{
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#if 0
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fprintf(stderr, "end: len %d size %d (%p)\n",
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(int) msg->len, (int) msg->msg_size, msg->buf);
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#endif
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assert(msg->len == msg->msg_size);
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if (msg->buf)
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flush_out(msg);
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free(msg);
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}
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static void add_chunk(struct fakefile_msg *msg, const void *buf, size_t len)
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{
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memcpy(msg->pos, buf, len);
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msg->pos += len;
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if (msg->pos == msg->buf+msg->buf_size) {
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flush_out(msg);
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msg->pos = msg->buf;
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}
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}
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void fakefile_msg_add(struct fakefile_msg *msg, const void *buf, size_t len)
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{
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size_t chunk;
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#if 0
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fprintf(stderr, "add: %d+%d/%d (%p)\n",
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(int) msg->len, (int) len, (int) msg->msg_size, msg->buf);
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#endif
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assert(msg->len+len <= msg->msg_size);
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while (len && msg->pos+len > msg->buf+msg->buf_size) {
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chunk = msg->buf+msg->buf_size-msg->pos;
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if (chunk > len)
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chunk = len;
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add_chunk(msg, buf, chunk);
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buf += chunk;
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len -= chunk;
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msg->len += chunk;
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}
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if (len) {
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add_chunk(msg, buf, len);
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msg->len += len;
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}
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}
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static size_t get_chunk(struct fakefile_peer *peer, void *buf, size_t len)
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{
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ssize_t got;
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got = read(peer->in, buf, len);
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if (got < 0) {
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perror("fakefile IPC read");
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exit(1);
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}
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if (!got) {
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fprintf(stderr, "fakefile EOF\n");
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exit(1);
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}
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return got;
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}
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void fakefile_msg_get(struct fakefile_msg *msg, void *buf, size_t len)
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{
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struct fakefile_peer *peer = msg->peer;
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size_t chunk, got;
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assert(msg->len+len <= msg->msg_size);
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if (!len)
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return;
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if (peer->pos != peer->end) {
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chunk = peer->end-peer->pos;
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if (chunk > len)
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chunk = len;
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memcpy(buf, peer->pos, chunk);
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peer->pos += chunk;
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buf += chunk;
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len -= chunk;
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msg->len += chunk;
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}
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while (len >= BUF_SIZE) {
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got = get_chunk(peer, buf, BUF_SIZE);
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buf += got;
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len -= got;
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msg->len += got;
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}
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if (!len)
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return;
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peer->pos = peer->buf;
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peer->end = peer->buf+get_chunk(peer, peer->buf, BUF_SIZE);
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fakefile_msg_get(msg, buf, len);
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}
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