io.c

Rsync 3.0.5 source code

/*
 * Socket and pipe I/O utilities used in rsync.
 *
 * Copyright (C) 1996-2001 Andrew Tridgell
 * Copyright (C) 1996 Paul Mackerras
 * Copyright (C) 2001, 2002 Martin Pool <[e-mail]>
 * Copyright (C) 2003-2008 Wayne Davison
 *
 * 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 3 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, visit the http://fsf.org website.
 */

/* Rsync provides its own multiplexing system, which is used to send
 * stderr and stdout over a single socket.
 *
 * For historical reasons this is off during the start of the
 * connection, but it's switched on quite early using
 * io_start_multiplex_out() and io_start_multiplex_in(). */

#include "rsync.h"
#include "ifuncs.h"

/** If no timeout is specified then use a 60 second select timeout */
#define SELECT_TIMEOUT 60

extern int bwlimit;
extern size_t bwlimit_writemax;
extern int io_timeout;
extern int allowed_lull;
extern int am_server;
extern int am_daemon;
extern int am_sender;
extern int am_generator;
extern int inc_recurse;
extern int io_error;
extern int eol_nulls;
extern int flist_eof;
extern int list_only;
extern int read_batch;
extern int csum_length;
extern int protect_args;
extern int checksum_seed;
extern int protocol_version;
extern int remove_source_files;
extern int preserve_hard_links;
extern struct stats stats;
extern struct file_list *cur_flist;
#ifdef ICONV_OPTION
extern int filesfrom_convert;
extern iconv_t ic_send, ic_recv;
#endif

const char phase_unknown[] = "unknown";
int ignore_timeout = 0;
int batch_fd = -1;
int msgdone_cnt = 0;

/* Ignore an EOF error if non-zero. See whine_about_eof(). */
int kluge_around_eof = 0;

int msg_fd_in = -1;
int msg_fd_out = -1;
int sock_f_in = -1;
int sock_f_out = -1;

static int iobuf_f_in = -1;
static char *iobuf_in;
static size_t iobuf_in_siz;
static size_t iobuf_in_ndx;
static size_t iobuf_in_remaining;

static int iobuf_f_out = -1;
static char *iobuf_out;
static int iobuf_out_cnt;

int flist_forward_from = -1;

static int io_multiplexing_out;
static int io_multiplexing_in;
static time_t last_io_in;
static time_t last_io_out;
static int no_flush;

static int write_batch_monitor_in = -1;
static int write_batch_monitor_out = -1;

static int io_filesfrom_f_in = -1;
static int io_filesfrom_f_out = -1;
static xbuf ff_buf = EMPTY_XBUF;
static char ff_lastchar;
#ifdef ICONV_OPTION
static xbuf iconv_buf = EMPTY_XBUF;
#endif
static int defer_forwarding_messages = 0, keep_defer_forwarding = 0;
static int select_timeout = SELECT_TIMEOUT;
static int active_filecnt = 0;
static OFF_T active_bytecnt = 0;
static int first_message = 1;

static char int_byte_extra[64] = {
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* (00 - 3F)/4 */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* (40 - 7F)/4 */
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* (80 - BF)/4 */
	2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 5, 6, /* (C0 - FF)/4 */
};

#define REMOTE_OPTION_ERROR "rsync: on remote machine: -"
#define REMOTE_OPTION_ERROR2 ": unknown option"

enum festatus { FES_SUCCESS, FES_REDO, FES_NO_SEND };

static void readfd(int fd, char *buffer, size_t N);
static void writefd(int fd, const char *buf, size_t len);
static void writefd_unbuffered(int fd, const char *buf, size_t len);
static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len, int convert);

static flist_ndx_list redo_list, hlink_list;

struct msg_list_item {
	struct msg_list_item *next;
	char convert;
	char buf[1];
};

struct msg_list {
	struct msg_list_item *head, *tail;
};

static struct msg_list msg_queue;

static void got_flist_entry_status(enum festatus status, const char *buf)
{
	int ndx = IVAL(buf, 0);
	struct file_list *flist = flist_for_ndx(ndx, "got_flist_entry_status");

	if (remove_source_files) {
		active_filecnt--;
		active_bytecnt -= F_LENGTH(flist->files[ndx - flist->ndx_start]);
	}

	if (inc_recurse)
		flist->in_progress--;

	switch (status) {
	case FES_SUCCESS:
		if (remove_source_files)
			send_msg(MSG_SUCCESS, buf, 4, 0);
		if (preserve_hard_links) {
			struct file_struct *file = flist->files[ndx - flist->ndx_start];
			if (F_IS_HLINKED(file)) {
				flist_ndx_push(&hlink_list, ndx);
				flist->in_progress++;
			}
		}
		break;
	case FES_REDO:
		if (read_batch) {
			if (inc_recurse)
				flist->in_progress++;
			break;
		}
		if (inc_recurse)
			flist->to_redo++;
		flist_ndx_push(&redo_list, ndx);
		break;
	case FES_NO_SEND:
		break;
	}
}

static void check_timeout(void)
{
	time_t t;

	if (!io_timeout || ignore_timeout)
		return;

	if (!last_io_in) {
		last_io_in = time(NULL);
		return;
	}

	t = time(NULL);

	if (t - last_io_in >= io_timeout) {
		if (!am_server && !am_daemon) {
			rprintf(FERROR, "io timeout after %d seconds -- exiting\n",
				(int)(t-last_io_in));
		}
		exit_cleanup(RERR_TIMEOUT);
	}
}

/* Note the fds used for the main socket (which might really be a pipe
 * for a local transfer, but we can ignore that). */
void io_set_sock_fds(int f_in, int f_out)
{
	sock_f_in = f_in;
	sock_f_out = f_out;
}

void set_io_timeout(int secs)
{
	io_timeout = secs;

	if (!io_timeout || io_timeout > SELECT_TIMEOUT)
		select_timeout = SELECT_TIMEOUT;
	else
		select_timeout = io_timeout;

	allowed_lull = read_batch ? 0 : (io_timeout + 1) / 2;
}

/* Setup the fd used to receive MSG_* messages.  Only needed during the
 * early stages of being a local sender (up through the sending of the
 * file list) or when we're the generator (to fetch the messages from
 * the receiver). */
void set_msg_fd_in(int fd)
{
	msg_fd_in = fd;
}

/* Setup the fd used to send our MSG_* messages.  Only needed when
 * we're the receiver (to send our messages to the generator). */
void set_msg_fd_out(int fd)
{
	msg_fd_out = fd;
	set_nonblocking(msg_fd_out);
}

/* Add a message to the pending MSG_* list. */
static void msg_list_add(struct msg_list *lst, int code, const char *buf, int len, int convert)
{
	struct msg_list_item *m;
	int sz = len + 4 + sizeof m[0] - 1;

	if (!(m = (struct msg_list_item *)new_array(char, sz)))
		out_of_memory("msg_list_add");
	m->next = NULL;
	m->convert = convert;
	SIVAL(m->buf, 0, ((code+MPLEX_BASE)<<24) | len);
	memcpy(m->buf + 4, buf, len);
	if (lst->tail)
		lst->tail->next = m;
	else
		lst->head = m;
	lst->tail = m;
}

static inline int flush_a_msg(int fd)
{
	struct msg_list_item *m = msg_queue.head;
	int len = IVAL(m->buf, 0) & 0xFFFFFF;
	int tag = *((uchar*)m->buf+3) - MPLEX_BASE;

	if (!(msg_queue.head = m->next))
		msg_queue.tail = NULL;

	defer_forwarding_messages++;
	mplex_write(fd, tag, m->buf + 4, len, m->convert);
	defer_forwarding_messages--;

	free(m);

	return len;
}

static void msg_flush(void)
{
	if (am_generator) {
		while (msg_queue.head && io_multiplexing_out)
			stats.total_written += flush_a_msg(sock_f_out) + 4;
	} else {
		while (msg_queue.head)
			(void)flush_a_msg(msg_fd_out);
	}
}

static void check_for_d_option_error(const char *msg)
{
	static char rsync263_opts[] = "BCDHIKLPRSTWabceghlnopqrtuvxz";
	char *colon;
	int saw_d = 0;

	if (*msg != 'r'
	 || strncmp(msg, REMOTE_OPTION_ERROR, sizeof REMOTE_OPTION_ERROR - 1) != 0)
		return;

	msg += sizeof REMOTE_OPTION_ERROR - 1;
	if (*msg == '-' || (colon = strchr(msg, ':')) == NULL
	 || strncmp(colon, REMOTE_OPTION_ERROR2, sizeof REMOTE_OPTION_ERROR2 - 1) != 0)
		return;

	for ( ; *msg != ':'; msg++) {
		if (*msg == 'd')
			saw_d = 1;
		else if (*msg == 'e')
			break;
		else if (strchr(rsync263_opts, *msg) == NULL)
			return;
	}

	if (saw_d) {
		rprintf(FWARNING,
		    "*** Try using \"--old-d\" if remote rsync is <= 2.6.3 ***\n");
	}
}

/* Read a message from the MSG_* fd and handle it.  This is called either
 * during the early stages of being a local sender (up through the sending
 * of the file list) or when we're the generator (to fetch the messages
 * from the receiver). */
static void read_msg_fd(void)
{
	char buf[2048];
	size_t n;
	struct file_list *flist;
	int fd = msg_fd_in;
	int tag, len;

	/* Temporarily disable msg_fd_in.  This is needed to avoid looping back
	 * to this routine from writefd_unbuffered(). */
	no_flush++;
	msg_fd_in = -1;
	defer_forwarding_messages++;

	readfd(fd, buf, 4);
	tag = IVAL(buf, 0);

	len = tag & 0xFFFFFF;
	tag = (tag >> 24) - MPLEX_BASE;

	switch (tag) {
	case MSG_DONE:
		if (len < 0 || len > 1 || !am_generator) {
		  invalid_msg:
			rprintf(FERROR, "invalid message %d:%d [%s%s]\n",
				tag, len, who_am_i(),
				inc_recurse ? "/inc" : "");
			exit_cleanup(RERR_STREAMIO);
		}
		if (len) {
			readfd(fd, buf, len);
			stats.total_read = read_varlong(fd, 3);
		}
		msgdone_cnt++;
		break;
	case MSG_REDO:
		if (len != 4 || !am_generator)
			goto invalid_msg;
		readfd(fd, buf, 4);
		got_flist_entry_status(FES_REDO, buf);
		break;
	case MSG_FLIST:
		if (len != 4 || !am_generator || !inc_recurse)
			goto invalid_msg;
		readfd(fd, buf, 4);
		/* Read extra file list from receiver. */
		assert(iobuf_in != NULL);
		assert(iobuf_f_in == fd);
		if (verbose > 3) {
			rprintf(FINFO, "[%s] receiving flist for dir %d\n",
				who_am_i(), IVAL(buf,0));
		}
		flist = recv_file_list(fd);
		flist->parent_ndx = IVAL(buf,0);
#ifdef SUPPORT_HARD_LINKS
		if (preserve_hard_links)
			match_hard_links(flist);
#endif
		break;
	case MSG_FLIST_EOF:
		if (len != 0 || !am_generator || !inc_recurse)
			goto invalid_msg;
		flist_eof = 1;
		break;
	case MSG_IO_ERROR:
		if (len != 4)
			goto invalid_msg;
		readfd(fd, buf, len);
		io_error |= IVAL(buf, 0);
		break;
	case MSG_DELETED:
		if (len >= (int)sizeof buf || !am_generator)
			goto invalid_msg;
		readfd(fd, buf, len);
		send_msg(MSG_DELETED, buf, len, 1);
		break;
	case MSG_SUCCESS:
		if (len != 4 || !am_generator)
			goto invalid_msg;
		readfd(fd, buf, 4);
		got_flist_entry_status(FES_SUCCESS, buf);
		break;
	case MSG_NO_SEND:
		if (len != 4 || !am_generator)
			goto invalid_msg;
		readfd(fd, buf, 4);
		got_flist_entry_status(FES_NO_SEND, buf);
		break;
	case MSG_ERROR_SOCKET:
	case MSG_ERROR_UTF8:
	case MSG_CLIENT:
		if (!am_generator)
			goto invalid_msg;
		if (tag == MSG_ERROR_SOCKET)
			io_end_multiplex_out();
		/* FALL THROUGH */
	case MSG_INFO:
	case MSG_ERROR:
	case MSG_ERROR_XFER:
	case MSG_WARNING:
	case MSG_LOG:
		while (len) {
			n = len;
			if (n >= sizeof buf)
				n = sizeof buf - 1;
			readfd(fd, buf, n);
			rwrite((enum logcode)tag, buf, n, !am_generator);
			len -= n;
		}
		break;
	default:
		rprintf(FERROR, "unknown message %d:%d [%s]\n",
			tag, len, who_am_i());
		exit_cleanup(RERR_STREAMIO);
	}

	no_flush--;
	msg_fd_in = fd;
	if (!--defer_forwarding_messages && !no_flush)
		msg_flush();
}

/* This is used by the generator to limit how many file transfers can
 * be active at once when --remove-source-files is specified.  Without
 * this, sender-side deletions were mostly happening at the end. */
void increment_active_files(int ndx, int itemizing, enum logcode code)
{
	while (1) {
		/* TODO: tune these limits? */
		int limit = active_bytecnt >= 128*1024 ? 10 : 50;
		if (active_filecnt < limit)
			break;
		check_for_finished_files(itemizing, code, 0);
		if (active_filecnt < limit)
			break;
		if (iobuf_out_cnt)
			io_flush(NORMAL_FLUSH);
		else
			read_msg_fd();
	}

	active_filecnt++;
	active_bytecnt += F_LENGTH(cur_flist->files[ndx - cur_flist->ndx_start]);
}

/* Write an message to a multiplexed stream. If this fails, rsync exits. */
static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len, int convert)
{
	char buffer[BIGPATHBUFLEN]; /* Oversized for use by iconv code. */
	size_t n = len;

#ifdef ICONV_OPTION
	/* We need to convert buf before doing anything else so that we
	 * can include the (converted) byte length in the message header. */
	if (convert && ic_send != (iconv_t)-1) {
		xbuf outbuf, inbuf;

		INIT_XBUF(outbuf, buffer + 4, 0, sizeof buffer - 4);
		INIT_XBUF(inbuf, (char*)buf, len, -1);

		iconvbufs(ic_send, &inbuf, &outbuf,
			  ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE);
		if (inbuf.len > 0) {
			rprintf(FERROR, "overflowed conversion buffer in mplex_write");
			exit_cleanup(RERR_UNSUPPORTED);
		}

		n = len = outbuf.len;
	} else
#endif
	if (n > 1024 - 4) /* BIGPATHBUFLEN can handle 1024 bytes */
		n = 0;    /* We'd rather do 2 writes than too much memcpy(). */
	else
		memcpy(buffer + 4, buf, n);

	SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);

	keep_defer_forwarding++; /* defer_forwarding_messages++ on return */
	writefd_unbuffered(fd, buffer, n+4);
	keep_defer_forwarding--;

	if (len > n)
		writefd_unbuffered(fd, buf+n, len-n);

	if (!--defer_forwarding_messages && !no_flush)
		msg_flush();
}

int send_msg(enum msgcode code, const char *buf, int len, int convert)
{
	if (msg_fd_out < 0) {
		if (!defer_forwarding_messages)
			return io_multiplex_write(code, buf, len, convert);
		if (!io_multiplexing_out)
			return 0;
		msg_list_add(&msg_queue, code, buf, len, convert);
		return 1;
	}
	if (flist_forward_from >= 0)
		msg_list_add(&msg_queue, code, buf, len, convert);
	else
		mplex_write(msg_fd_out, code, buf, len, convert);
	return 1;
}

void send_msg_int(enum msgcode code, int num)
{
	char numbuf[4];
	SIVAL(numbuf, 0, num);
	send_msg(code, numbuf, 4, 0);
}

void wait_for_receiver(void)
{
	if (io_flush(NORMAL_FLUSH))
		return;
	read_msg_fd();
}

int get_redo_num(void)
{
	return flist_ndx_pop(&redo_list);
}

int get_hlink_num(void)
{
	return flist_ndx_pop(&hlink_list);
}

/**
 * When we're the receiver and we have a local --files-from list of names
 * that needs to be sent over the socket to the sender, we have to do two
 * things at the same time: send the sender a list of what files we're
 * processing and read the incoming file+info list from the sender.  We do
 * this by augmenting the read_timeout() function to copy this data.  It
 * uses ff_buf to read a block of data from f_in (when it is ready, since
 * it might be a pipe) and then blast it out f_out (when it is ready to
 * receive more data).
 */
void io_set_filesfrom_fds(int f_in, int f_out)
{
	io_filesfrom_f_in = f_in;
	io_filesfrom_f_out = f_out;
	alloc_xbuf(&ff_buf, 2048);
#ifdef ICONV_OPTION
	if (protect_args)
		alloc_xbuf(&iconv_buf, 1024);
#endif
}

/* It's almost always an error to get an EOF when we're trying to read from the
 * network, because the protocol is (for the most part) self-terminating.
 *
 * There is one case for the receiver when it is at the end of the transfer
 * (hanging around reading any keep-alive packets that might come its way): if
 * the sender dies before the generator's kill-signal comes through, we can end
 * up here needing to loop until the kill-signal arrives.  In this situation,
 * kluge_around_eof will be < 0.
 *
 * There is another case for older protocol versions (< 24) where the module
 * listing was not terminated, so we must ignore an EOF error in that case and
 * exit.  In this situation, kluge_around_eof will be > 0. */
static void whine_about_eof(int fd)
{
	if (kluge_around_eof && fd == sock_f_in) {
		int i;
		if (kluge_around_eof > 0)
			exit_cleanup(0);
		/* If we're still here after 10 seconds, exit with an error. */
		for (i = 10*1000/20; i--; )
			msleep(20);
	}

	rprintf(FERROR, RSYNC_NAME ": connection unexpectedly closed "
		"(%.0f bytes received so far) [%s]\n",
		(double)stats.total_read, who_am_i());

	exit_cleanup(RERR_STREAMIO);
}

/**
 * Read from a socket with I/O timeout. return the number of bytes
 * read. If no bytes can be read then exit, never return a number <= 0.
 *
 * TODO: If the remote shell connection fails, then current versions
 * actually report an "unexpected EOF" error here.  Since it's a
 * fairly common mistake to try to use rsh when ssh is required, we
 * should trap that: if we fail to read any data at all, we should
 * give a better explanation.  We can tell whether the connection has
 * started by looking e.g. at whether the remote version is known yet.
 */
static int read_timeout(int fd, char *buf, size_t len)
{
	int n, cnt = 0;

	io_flush(FULL_FLUSH);

	while (cnt == 0) {
		/* until we manage to read *something* */
		fd_set r_fds, w_fds;
		struct timeval tv;
		int maxfd = fd;
		int count;

		FD_ZERO(&r_fds);
		FD_ZERO(&w_fds);
		FD_SET(fd, &r_fds);
		if (io_filesfrom_f_out >= 0) {
			int new_fd;
			if (ff_buf.len == 0) {
				if (io_filesfrom_f_in >= 0) {