/* -*- c-file-style: "linux" -*- * * Copyright (C) 1996-2001 by Andrew Tridgell * Copyright (C) Paul Mackerras 1996 * Copyright (C) 2001, 2002 by Martin Pool * * 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. */ /** * @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(). **/ #include "rsync.h" /** If no timeout is specified then use a 60 second select timeout */ #define SELECT_TIMEOUT 60 static int io_multiplexing_out; static int io_multiplexing_in; static int multiplex_in_fd = -1; static int multiplex_out_fd = -1; static time_t last_io; static int no_flush; extern int bwlimit; extern int verbose; extern int io_timeout; extern struct stats stats; const char phase_unknown[] = "unknown"; /** * 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. * * For buffered/multiplexed IO these names will be somewhat * approximate; perhaps for ease of support we would rather make the * buffer always flush when a single application-level IO finishes. * * @todo Perhaps we want some simple stack functionality, but there's * no need to overdo it. **/ const char *io_write_phase = phase_unknown; const char *io_read_phase = 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 int io_filesfrom_f_in = -1; static int io_filesfrom_f_out = -1; static char io_filesfrom_buf[2048]; static char *io_filesfrom_bp; static char io_filesfrom_lastchar; static int io_filesfrom_buflen; static void read_loop(int fd, char *buf, size_t len); static void check_timeout(void) { extern int am_server, am_daemon; time_t t; err_list_push(); if (!io_timeout) return; if (!last_io) { last_io = time(NULL); return; } t = time(NULL); if (last_io && io_timeout && (t-last_io) >= io_timeout) { if (!am_server && !am_daemon) { rprintf(FERROR,"io timeout after %d seconds - exiting\n", (int)(t-last_io)); } exit_cleanup(RERR_TIMEOUT); } } /** Setup the fd used to propagate 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 */ static void read_error_fd(void) { char buf[200]; size_t n; int fd = io_error_fd; int tag, len; /* io_error_fd is temporarily disabled -- is this meant to * prevent indefinite recursion? */ io_error_fd = -1; read_loop(fd, buf, 4); tag = IVAL(buf, 0); len = tag & 0xFFFFFF; tag = tag >> 24; tag -= MPLEX_BASE; while (len) { n = len; if (n > (sizeof buf - 1)) n = sizeof buf - 1; read_loop(fd, buf, n); rwrite((enum logcode)tag, buf, n); len -= n; } io_error_fd = fd; } /** * 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 the io_filesfrom_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; io_filesfrom_bp = io_filesfrom_buf; io_filesfrom_lastchar = '\0'; io_filesfrom_buflen = 0; } /** * 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. * * 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, ret=0; io_flush(); while (ret == 0) { /* until we manage to read *something* */ fd_set r_fds, w_fds; struct timeval tv; int fd_count = fd+1; int count; FD_ZERO(&r_fds); FD_SET(fd, &r_fds); if (io_error_fd != -1) { FD_SET(io_error_fd, &r_fds); if (io_error_fd >= fd_count) fd_count = io_error_fd+1; } if (io_filesfrom_f_out != -1) { int new_fd; if (io_filesfrom_buflen == 0) { if (io_filesfrom_f_in != -1) { FD_SET(io_filesfrom_f_in, &r_fds); new_fd = io_filesfrom_f_in; } else { io_filesfrom_f_out = -1; new_fd = -1; } } else { FD_ZERO(&w_fds); FD_SET(io_filesfrom_f_out, &w_fds); new_fd = io_filesfrom_f_out; } if (new_fd >= fd_count) fd_count = new_fd+1; } tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT; tv.tv_usec = 0; errno = 0; count = select(fd_count, &r_fds, io_filesfrom_buflen? &w_fds : NULL, NULL, &tv); if (count == 0) { check_timeout(); } if (count <= 0) { if (errno == EBADF) { exit_cleanup(RERR_SOCKETIO); } continue; } if (io_error_fd != -1 && FD_ISSET(io_error_fd, &r_fds)) { read_error_fd(); } if (io_filesfrom_f_out != -1) { if (io_filesfrom_buflen) { if (FD_ISSET(io_filesfrom_f_out, &w_fds)) { int l = write(io_filesfrom_f_out, io_filesfrom_bp, io_filesfrom_buflen); if (l > 0) { if (!(io_filesfrom_buflen -= l)) io_filesfrom_bp = io_filesfrom_buf; else io_filesfrom_bp += l; } else { /* XXX should we complain? */ io_filesfrom_f_out = -1; } } } else if (io_filesfrom_f_in != -1) { if (FD_ISSET(io_filesfrom_f_in, &r_fds)) { int l = read(io_filesfrom_f_in, io_filesfrom_buf, sizeof io_filesfrom_buf); if (l <= 0) { /* Send end-of-file marker */ io_filesfrom_buf[0] = '\0'; io_filesfrom_buf[1] = '\0'; io_filesfrom_buflen = io_filesfrom_lastchar? 2 : 1; io_filesfrom_f_in = -1; } else { extern int eol_nulls; if (!eol_nulls) { char *s = io_filesfrom_buf + l; /* Transform CR and/or LF into '\0' */ while (s-- > io_filesfrom_buf) { if (*s == '\n' || *s == '\r') *s = '\0'; } } if (!io_filesfrom_lastchar) { /* Last buf ended with a '\0', so don't * let this buf start with one. */ while (l && !*io_filesfrom_bp) io_filesfrom_bp++, l--; } if (!l) io_filesfrom_bp = io_filesfrom_buf; else { char *f = io_filesfrom_bp; char *t = f; char *eob = f + l; /* Eliminate any multi-'\0' runs. */ while (f != eob) { if (!(*t++ = *f++)) { while (f != eob && !*f) f++, l--; } } io_filesfrom_lastchar = f[-1]; } io_filesfrom_buflen = l; } } } } if (!FD_ISSET(fd, &r_fds)) continue; n = read(fd, buf, len); if (n > 0) { buf += n; len -= n; ret += n; 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; die_from_readerr(errno); } } return ret; } /** * Read a line into the "fname" buffer (which must be at least MAXPATHLEN * characters long). */ int read_filesfrom_line(int fd, char *fname) { char ch, *s, *eob = fname + MAXPATHLEN - 1; int cnt; extern int io_timeout; extern int eol_nulls; extern char *remote_filesfrom_file; int reading_remotely = remote_filesfrom_file != NULL; int nulls = eol_nulls || reading_remotely; start: s = fname; while (1) { cnt = read(fd, &ch, 1); if (cnt < 0 && (errno == EWOULDBLOCK || errno == EINTR || errno == EAGAIN)) { struct timeval tv; fd_set fds; FD_ZERO(&fds); FD_SET(fd, &fds); tv.tv_sec = io_timeout? io_timeout : SELECT_TIMEOUT; tv.tv_usec = 0; if (!select(fd+1, &fds, NULL, NULL, &tv)) check_timeout(); continue; } if (cnt != 1) break; if (nulls? !ch : (ch == '\r' || ch == '\n')) { /* Skip empty lines if reading locally. */ if (!reading_remotely && s == fname) continue; break; } if (s < eob) *s++ = ch; } *s = '\0'; /* Dump comments. */ if (*fname == '#' || *fname == ';') goto start; return s - fname; } /** * 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); buf += n; len -= n; } } /** * 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 size_t remaining; int tag, ret = 0; char line[1024]; static char *buffer; static size_t bufferIdx = 0; static size_t bufferSz; if (fd != multiplex_in_fd) return read_timeout(fd, buf, len); if (!io_multiplexing_in && remaining == 0) { if (!buffer) { bufferSz = 2 * IO_BUFFER_SIZE; buffer = new_array(char, bufferSz); if (!buffer) out_of_memory("read_unbuffered"); } remaining = read_timeout(fd, buffer, bufferSz); bufferIdx = 0; } while (ret == 0) { if (remaining) { len = MIN(len, remaining); memcpy(buf, buffer + bufferIdx, len); bufferIdx += len; remaining -= len; ret = len; break; } read_loop(fd, line, 4); tag = IVAL(line, 0); remaining = tag & 0xFFFFFF; tag = tag >> 24; if (tag == MPLEX_BASE) { if (!buffer || remaining > bufferSz) { buffer = realloc_array(buffer, char, remaining); if (!buffer) out_of_memory("read_unbuffered"); bufferSz = remaining; } read_loop(fd, buffer, remaining); bufferIdx = 0; continue; } tag -= MPLEX_BASE; if (tag != FERROR && tag != FINFO) { rprintf(FERROR, "unexpected tag %d\n", tag); exit_cleanup(RERR_STREAMIO); } if (remaining > sizeof line - 1) { rprintf(FERROR, "multiplexing overflow %ld\n\n", (long)remaining); exit_cleanup(RERR_STREAMIO); } read_loop(fd, line, remaining); line[remaining] = 0; rprintf((enum logcode) tag, "%s", line); remaining = 0; } if (remaining == 0) io_flush(); return ret; } /** * 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; size_t total=0; while (total < N) { ret = read_unbuffered(fd, buffer + total, N-total); total += ret; } stats.total_read += total; } int32 read_int(int f) { char b[4]; int32 ret; readfd(f,b,4); ret = IVAL(b,0); if (ret == (int32)0xffffffff) return -1; return ret; } int64 read_longint(int f) { int64 ret; char b[8]; ret = read_int(f); if ((int32)ret != (int32)0xffffffff) { return ret; } #ifdef NO_INT64 rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n"); exit_cleanup(RERR_UNSUPPORTED); #else readfd(f,b,8); ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32); #endif return ret; } void read_buf(int f,char *buf,size_t len) { readfd(f,buf,len); } void read_sbuf(int f,char *buf,size_t len) { read_buf(f,buf,len); buf[len] = 0; } unsigned char read_byte(int f) { unsigned char c; read_buf(f, (char *)&c, 1); return c; } /** * 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) { 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; err_list_push(); no_flush++; while (total < len) { FD_ZERO(&w_fds); FD_SET(fd,&w_fds); fd_count = fd; if (io_error_fd != -1) { FD_ZERO(&r_fds); FD_SET(io_error_fd,&r_fds); if (io_error_fd > fd_count) fd_count = io_error_fd; } tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT; tv.tv_usec = 0; errno = 0; count = select(fd_count+1, io_error_fd != -1?&r_fds:NULL, &w_fds,NULL, &tv); if (count == 0) { check_timeout(); } if (count <= 0) { if (errno == EBADF) { exit_cleanup(RERR_SOCKETIO); } continue; } if (io_error_fd != -1 && FD_ISSET(io_error_fd, &r_fds)) { read_error_fd(); } if (FD_ISSET(fd, &w_fds)) { int ret; size_t n = len-total; ret = write(fd,buf+total,n); if (ret == -1 && errno == EINTR) { continue; } if (ret == -1 && (errno == EWOULDBLOCK || errno == EAGAIN)) { msleep(1); continue; } if (ret <= 0) { /* 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_for_bwlimit(ret); total += ret; if (io_timeout) last_io = time(NULL); } } no_flush--; } static char *io_buffer; static int io_buffer_count; void io_start_buffering_out(int fd) { if (io_buffer) return; multiplex_out_fd = fd; io_buffer = new_array(char, IO_BUFFER_SIZE); if (!io_buffer) out_of_memory("writefd"); io_buffer_count = 0; } void io_start_buffering_in(int fd) { multiplex_in_fd = fd; } /** * 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]; size_t n = len; SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len); if (n > (sizeof buffer - 4)) { n = sizeof buffer - 4; } memcpy(&buffer[4], buf, n); writefd_unbuffered(fd, buffer, n+4); len -= n; buf += n; if (len) { writefd_unbuffered(fd, buf, len); } } void io_flush(void) { int fd = multiplex_out_fd; err_list_push(); if (!io_buffer_count || no_flush) return; if (io_multiplexing_out) { mplex_write(fd, FNONE, io_buffer, io_buffer_count); } else { writefd_unbuffered(fd, io_buffer, io_buffer_count); } io_buffer_count = 0; } void io_end_buffering(void) { io_flush(); if (!io_multiplexing_out) { free(io_buffer); io_buffer = NULL; } } static void writefd(int fd,char *buf,size_t len) { stats.total_written += len; err_list_push(); if (!io_buffer || fd != multiplex_out_fd) { writefd_unbuffered(fd, buf, len); return; } while (len) { int n = MIN((int) len, IO_BUFFER_SIZE-io_buffer_count); if (n > 0) { memcpy(io_buffer+io_buffer_count, buf, n); buf += n; len -= n; io_buffer_count += n; } if (io_buffer_count == IO_BUFFER_SIZE) io_flush(); } } void write_int(int f,int32 x) { char b[4]; SIVAL(b,0,x); writefd(f,b,4); } void write_int_named(int f, int32 x, const char *phase) { io_write_phase = phase; write_int(f, x); io_write_phase = phase_unknown; } /* * Note: int64 may actually be a 32-bit type if ./configure couldn't find any * 64-bit types on this platform. */ void write_longint(int f, int64 x) { char b[8]; if (x <= 0x7FFFFFFF) { write_int(f, (int)x); return; } #ifdef NO_INT64 rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n"); exit_cleanup(RERR_UNSUPPORTED); #else write_int(f, (int32)0xFFFFFFFF); SIVAL(b,0,(x&0xFFFFFFFF)); SIVAL(b,4,((x>>32)&0xFFFFFFFF)); writefd(f,b,8); #endif } void write_buf(int f,char *buf,size_t len) { writefd(f,buf,len); } /** Write a string to the connection */ static void write_sbuf(int f,char *buf) { write_buf(f, buf, strlen(buf)); } void write_byte(int f,unsigned char c) { write_buf(f,(char *)&c,1); } /** * 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] == '\n') { buf[0] = 0; break; } if (buf[0] != '\r') { buf++; maxlen--; } } if (maxlen == 0) { *buf = 0; return 0; } return 1; } void io_printf(int fd, const char *format, ...) { va_list ap; char buf[1024]; int len; va_start(ap, format); len = vsnprintf(buf, sizeof buf, format, ap); va_end(ap); if (len < 0) exit_cleanup(RERR_STREAMIO); write_sbuf(fd, buf); } /** Setup for multiplexing an error stream with the data stream */ void io_start_multiplex_out(int fd) { multiplex_out_fd = fd; io_flush(); io_start_buffering_out(fd); io_multiplexing_out = 1; } /** Setup for multiplexing an error stream with the data stream */ void io_start_multiplex_in(int fd) { multiplex_in_fd = fd; io_flush(); io_multiplexing_in = 1; } /** 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; io_flush(); stats.total_written += (len+4); mplex_write(multiplex_out_fd, code, buf, len); return 1; } /** Stop output multiplexing */ void io_multiplexing_close(void) { io_multiplexing_out = 0; }