/* -*- c-file-style: "linux" -*-
-
- Copyright (C) 1996-2001 by Andrew Tridgell
- Copyright (C) Paul Mackerras 1996
-
- 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 2 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, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
+ *
+ * Copyright (C) 1996-2001 by Andrew Tridgell
+ * Copyright (C) Paul Mackerras 1996
+ * Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
-/*
- socket and pipe IO utilities used in rsync
+/**
+ * @file io.c
+ *
+ * Socket and pipe IO utilities used in rsync.
+ *
+ * rsync provides its own multiplexing system, which is used to send
+ * stderr and stdout over a single socket. We need this because
+ * stdout normally carries the binary data stream, and stderr all our
+ * error messages.
+ *
+ * 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().
+ **/
- tridge, June 1996
- */
#include "rsync.h"
-/* if no timeout is specified then use a 60 second select timeout */
+/** If no timeout is specified then use a 60 second select timeout */
#define SELECT_TIMEOUT 60
-extern int bwlimit;
-
static int io_multiplexing_out;
static int io_multiplexing_in;
static int multiplex_in_fd;
static int multiplex_out_fd;
static time_t last_io;
-static int eof_error=1;
+static int no_flush;
+
+extern int bwlimit;
extern int verbose;
extern int io_timeout;
extern struct stats stats;
+
+/**
+ * The connection might be dropped at some point; perhaps because the
+ * remote instance crashed. Just giving the offset on the stream is
+ * not very helpful. So instead we try to make io_phase_name point to
+ * something useful.
+ *
+ * @todo Perhaps we want some simple stack functionality, but there's
+ * no need to overdo it.
+ **/
+const char *io_write_phase = "unknown";
+const char *io_read_phase = "unknown";
+
+
+/** Ignore EOF errors while reading a module listing if the remote
+ version is 24 or less. */
+int kludge_around_eof = False;
+
+
static int io_error_fd = -1;
-static void read_loop(int fd, char *buf, int len);
+static void read_loop(int fd, char *buf, size_t len);
static void check_timeout(void)
{
}
}
-/* setup the fd used to propogate errors */
+/** Setup the fd used to propogate errors */
void io_set_error_fd(int fd)
{
io_error_fd = fd;
}
-/* read some data from the error fd and write it to the write log code */
+/** Read some data from the error fd and write it to the write log code */
static void read_error_fd(void)
{
char buf[200];
- int n;
+ size_t n;
int fd = io_error_fd;
int tag, len;
while (len) {
n = len;
- if (n > (sizeof(buf)-1)) n = sizeof(buf)-1;
+ if (n > (sizeof(buf)-1))
+ n = sizeof(buf)-1;
read_loop(fd, buf, n);
rwrite((enum logcode)tag, buf, n);
len -= n;
}
-static int no_flush;
+/**
+ * It's almost always an error to get an EOF when we're trying to read
+ * from the network, because the protocol is self-terminating.
+ *
+ * However, there is one unfortunate cases where it is not, which is
+ * rsync <2.4.6 sending a list of modules on a server, since the list
+ * is terminated by closing the socket. So, for the section of the
+ * program where that is a problem (start_socket_client),
+ * kludge_around_eof is True and we just exit.
+ */
+static void whine_about_eof (void)
+{
+ if (kludge_around_eof)
+ exit_cleanup (0);
+ else {
+ rprintf (FERROR,
+ "%s: connection unexpectedly closed "
+ "(%.0f bytes read so far)\n",
+ RSYNC_NAME, (double)stats.total_read);
+
+ exit_cleanup (RERR_STREAMIO);
+ }
+}
-/*
+
+static void die_from_readerr (int err)
+{
+ /* this prevents us trying to write errors on a dead socket */
+ io_multiplexing_close();
+
+ rprintf(FERROR, "%s: read error: %s\n",
+ RSYNC_NAME, strerror (err));
+ exit_cleanup(RERR_STREAMIO);
+}
+
+
+/**
* Read from a socket with IO timeout. return the number of bytes
* read. If no bytes can be read then exit, never return a number <= 0.
*
* 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, int len)
+static int read_timeout (int fd, char *buf, size_t len)
{
int n, ret=0;
io_flush();
while (ret == 0) {
+ /* until we manage to read *something* */
fd_set fds;
struct timeval tv;
int fd_count = fd+1;
+ int count;
FD_ZERO(&fds);
FD_SET(fd, &fds);
errno = 0;
- if (select(fd_count, &fds, NULL, NULL, &tv) < 1) {
+ count = select(fd_count, &fds, NULL, NULL, &tv);
+
+ if (count == 0) {
+ check_timeout();
+ }
+
+ if (count <= 0) {
if (errno == EBADF) {
exit_cleanup(RERR_SOCKETIO);
}
- check_timeout();
continue;
}
if (io_timeout)
last_io = time(NULL);
continue;
+ } else if (n == 0) {
+ whine_about_eof ();
+ return -1; /* doesn't return */
+ } else if (n == -1) {
+ if (errno == EINTR || errno == EWOULDBLOCK ||
+ errno == EAGAIN)
+ continue;
+ else
+ die_from_readerr (errno);
}
-
- if (n == -1 && errno == EINTR) {
- continue;
- }
-
- if (n == -1 &&
- (errno == EWOULDBLOCK || errno == EAGAIN)) {
- continue;
- }
-
-
- if (n == 0) {
- if (eof_error) {
- rprintf(FERROR,
- "%s: connection to server unexpectedly closed"
- " (%.0f bytes read so far)\n",
- RSYNC_NAME, (double)stats.total_read);
- }
- exit_cleanup(RERR_STREAMIO);
- }
-
- /* this prevents us trying to write errors on a dead socket */
- io_multiplexing_close();
-
- rprintf(FERROR,"read error: %s\n", strerror(errno));
- exit_cleanup(RERR_STREAMIO);
}
return ret;
}
-/* continue trying to read len bytes - don't return until len
- has been read */
-static void read_loop(int fd, char *buf, int len)
+
+
+
+/**
+ * Continue trying to read len bytes - don't return until len has been
+ * read.
+ **/
+static void read_loop (int fd, char *buf, size_t len)
{
while (len) {
int n = read_timeout(fd, buf, len);
}
}
-/* read from the file descriptor handling multiplexing -
- return number of bytes read
- never return <= 0 */
-static int read_unbuffered(int fd, char *buf, int len)
+
+/**
+ * Read from the file descriptor handling multiplexing - return number
+ * of bytes read.
+ *
+ * Never returns <= 0.
+ */
+static int read_unbuffered(int fd, char *buf, size_t len)
{
- static int remaining;
- int tag, ret=0;
+ static size_t remaining;
+ int tag, ret = 0;
char line[1024];
- if (!io_multiplexing_in || fd != multiplex_in_fd)
+ if (!io_multiplexing_in || fd != multiplex_in_fd)
return read_timeout(fd, buf, len);
while (ret == 0) {
remaining = tag & 0xFFFFFF;
tag = tag >> 24;
- if (tag == MPLEX_BASE) continue;
+ if (tag == MPLEX_BASE)
+ continue;
tag -= MPLEX_BASE;
if (tag != FERROR && tag != FINFO) {
- rprintf(FERROR,"unexpected tag %d\n", tag);
+ rprintf(FERROR, "unexpected tag %d\n", tag);
exit_cleanup(RERR_STREAMIO);
}
- if (remaining > sizeof(line)-1) {
- rprintf(FERROR,"multiplexing overflow %d\n\n",
+ if (remaining > sizeof(line) - 1) {
+ rprintf(FERROR, "multiplexing overflow %d\n\n",
remaining);
exit_cleanup(RERR_STREAMIO);
}
read_loop(fd, line, remaining);
line[remaining] = 0;
- rprintf((enum logcode)tag,"%s", line);
+ rprintf((enum logcode) tag, "%s", line);
remaining = 0;
}
}
-/* do a buffered read from fd. don't return until all N bytes
- have been read. If all N can't be read then exit with an error */
-static void readfd(int fd,char *buffer,int N)
+
+/**
+ * Do a buffered read from @p fd. Don't return until all @p n bytes
+ * have been read. If all @p n can't be read then exit with an
+ * error.
+ **/
+static void readfd (int fd, char *buffer, size_t N)
{
int ret;
- int total=0;
+ size_t total=0;
while (total < N) {
io_flush();
- ret = read_unbuffered(fd,buffer + total,N-total);
+ ret = read_unbuffered (fd, buffer + total, N-total);
total += ret;
}
return ret;
}
-void read_buf(int f,char *buf,int len)
+void read_buf(int f,char *buf,size_t len)
{
readfd(f,buf,len);
}
-void read_sbuf(int f,char *buf,int len)
+void read_sbuf(int f,char *buf,size_t len)
{
- read_buf(f,buf,len);
+ read_buf (f,buf,len);
buf[len] = 0;
}
unsigned char read_byte(int f)
{
unsigned char c;
- read_buf(f,(char *)&c,1);
+ read_buf (f, (char *)&c, 1);
return c;
}
-/* write len bytes to fd */
-static void writefd_unbuffered(int fd,char *buf,int len)
+
+/**
+ * Sleep after writing to limit I/O bandwidth usage.
+ *
+ * @todo Rather than sleeping after each write, it might be better to
+ * use some kind of averaging. The current algorithm seems to always
+ * use a bit less bandwidth than specified, because it doesn't make up
+ * for slow periods. But arguably this is a feature. In addition, we
+ * ought to take the time used to write the data into account.
+ **/
+static void sleep_for_bwlimit(int bytes_written)
{
- int total = 0;
+ struct timeval tv;
+
+ if (!bwlimit)
+ return;
+
+ assert(bytes_written > 0);
+ assert(bwlimit > 0);
+
+ tv.tv_usec = bytes_written * 1000 / bwlimit;
+ tv.tv_sec = tv.tv_usec / 1000000;
+ tv.tv_usec = tv.tv_usec % 1000000;
+
+ select(0, NULL, NULL, NULL, &tv);
+}
+
+
+/**
+ * Write len bytes to the file descriptor @p fd.
+ *
+ * This function underlies the multiplexing system. The body of the
+ * application never calls this function directly.
+ **/
+static void writefd_unbuffered(int fd,char *buf,size_t len)
+{
+ size_t total = 0;
fd_set w_fds, r_fds;
int fd_count, count;
struct timeval tv;
&w_fds,NULL,
&tv);
+ if (count == 0) {
+ check_timeout();
+ }
+
if (count <= 0) {
if (errno == EBADF) {
exit_cleanup(RERR_SOCKETIO);
}
- check_timeout();
continue;
}
}
if (FD_ISSET(fd, &w_fds)) {
- int ret, n = len-total;
+ int ret;
+ size_t n = len-total;
ret = write(fd,buf+total,n);
if (ret == -1 && errno == EINTR) {
}
if (ret <= 0) {
- rprintf(FERROR,
- "error writing %d unbuffered bytes"
- " - exiting: %s\n", len,
+ /* Don't try to write errors back
+ * across the stream */
+ io_multiplexing_close();
+ rprintf(FERROR, RSYNC_NAME
+ ": writefd_unbuffered failed to write %ld bytes: phase \"%s\": %s\n",
+ (long) len, io_write_phase,
strerror(errno));
exit_cleanup(RERR_STREAMIO);
}
- /* Sleep after writing to limit I/O bandwidth */
- if (bwlimit)
- {
- tv.tv_sec = 0;
- tv.tv_usec = ret * 1000 / bwlimit;
- while (tv.tv_usec > 1000000)
- {
- tv.tv_sec++;
- tv.tv_usec -= 1000000;
- }
- select(0, NULL, NULL, NULL, &tv);
- }
+ sleep_for_bwlimit(ret);
total += ret;
io_buffer_count = 0;
}
-/* write an message to a multiplexed stream. If this fails then rsync
- exits */
-static void mplex_write(int fd, enum logcode code, char *buf, int len)
+/**
+ * Write an message to a multiplexed stream. If this fails then rsync
+ * exits.
+ **/
+static void mplex_write(int fd, enum logcode code, char *buf, size_t len)
{
char buffer[4096];
- int n = len;
+ size_t n = len;
SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
}
-/* XXX: fd is ignored, which seems a little strange. */
-void io_end_buffering(int fd)
+void io_end_buffering(void)
{
io_flush();
if (!io_multiplexing_out) {
}
}
-static void writefd(int fd,char *buf,int len)
+static void writefd(int fd,char *buf,size_t len)
{
stats.total_written += len;
}
while (len) {
- int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
+ int n = MIN((int) len, IO_BUFFER_SIZE-io_buffer_count);
if (n > 0) {
memcpy(io_buffer+io_buffer_count, buf, n);
buf += n;
writefd(f,b,8);
}
-void write_buf(int f,char *buf,int len)
+void write_buf(int f,char *buf,size_t len)
{
writefd(f,buf,len);
}
-/* write a string to the connection */
+/** Write a string to the connection */
static void write_sbuf(int f,char *buf)
{
write_buf(f, buf, strlen(buf));
write_buf(f,(char *)&c,1);
}
-int read_line(int f, char *buf, int maxlen)
-{
- eof_error = 0;
+
+/**
+ * Read a line of up to @p maxlen characters into @p buf. Does not
+ * contain a trailing newline or carriage return.
+ *
+ * @return 1 for success; 0 for io error or truncation.
+ **/
+int read_line(int f, char *buf, size_t maxlen)
+{
while (maxlen) {
buf[0] = 0;
read_buf(f, buf, 1);
- if (buf[0] == 0) return 0;
+ if (buf[0] == 0)
+ return 0;
if (buf[0] == '\n') {
buf[0] = 0;
break;
return 0;
}
- eof_error = 1;
-
return 1;
}
int len;
va_start(ap, format);
- len = vslprintf(buf, sizeof(buf), format, ap);
+ len = vsnprintf(buf, sizeof(buf), format, ap);
va_end(ap);
if (len < 0) exit_cleanup(RERR_STREAMIO);
}
-/* setup for multiplexing an error stream with the data stream */
+/** Setup for multiplexing an error stream with the data stream */
void io_start_multiplex_out(int fd)
{
multiplex_out_fd = fd;
io_multiplexing_out = 1;
}
-/* setup for multiplexing an error stream with the data stream */
+/** Setup for multiplexing an error stream with the data stream */
void io_start_multiplex_in(int fd)
{
multiplex_in_fd = fd;
io_multiplexing_in = 1;
}
-/* write an message to the multiplexed error stream */
-int io_multiplex_write(enum logcode code, char *buf, int len)
+/** Write an message to the multiplexed error stream */
+int io_multiplex_write(enum logcode code, char *buf, size_t len)
{
if (!io_multiplexing_out) return 0;
return 1;
}
-/* stop output multiplexing */
+/** Stop output multiplexing */
void io_multiplexing_close(void)
{
io_multiplexing_out = 0;
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