X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/0ba481368c2a44d6d6a2f361fa12df432d9d304b..b35d0d8e9ae9c5407c9f781b545f8a66b9caa9d0:/io.c diff --git a/io.c b/io.c index b58eff0c..ed6a70c3 100644 --- a/io.c +++ b/io.c @@ -1,6 +1,8 @@ -/* - Copyright (C) Andrew Tridgell 1996 +/* -*- 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 @@ -17,36 +19,54 @@ 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 */ #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; + +/** 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) { extern int am_server, am_daemon; time_t t; + + err_list_push(); if (!io_timeout) return; @@ -59,7 +79,7 @@ static void check_timeout(void) if (last_io && io_timeout && (t-last_io) >= io_timeout) { if (!am_server && !am_daemon) { - rprintf(FERROR,"io timeout after %d second - exiting\n", + rprintf(FERROR,"io timeout after %d seconds - exiting\n", (int)(t-last_io)); } exit_cleanup(RERR_TIMEOUT); @@ -76,10 +96,12 @@ void io_set_error_fd(int fd) static void read_error_fd(void) { char buf[200]; - int n; + 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); @@ -91,7 +113,8 @@ static void read_error_fd(void) 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; @@ -101,21 +124,68 @@ static void read_error_fd(void) } -static int no_flush; +static void whine_about_eof (void) +{ + /** + 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. + */ + + 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); + } +} -/* 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 */ -static int read_timeout(int fd, char *buf, int len) + +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 fds; struct timeval tv; int fd_count = fd+1; + int count; FD_ZERO(&fds); FD_SET(fd, &fds); @@ -129,11 +199,16 @@ static int read_timeout(int fd, char *buf, int len) 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; } @@ -152,38 +227,27 @@ static int read_timeout(int fd, char *buf, int len) 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,"unexpected EOF in read_timeout\n"); - } - 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); @@ -193,16 +257,20 @@ static void read_loop(int fd, char *buf, int 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) { @@ -220,17 +288,18 @@ static int read_unbuffered(int fd, char *buf, int len) 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); } @@ -238,7 +307,7 @@ static int read_unbuffered(int fd, char *buf, int len) read_loop(fd, line, remaining); line[remaining] = 0; - rprintf((enum logcode)tag,"%s", line); + rprintf((enum logcode) tag, "%s", line); remaining = 0; } @@ -246,17 +315,18 @@ static int read_unbuffered(int fd, char *buf, int len) } + /* 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) +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; } @@ -299,32 +369,35 @@ int64 read_longint(int f) 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) +/* Write len bytes to fd. This underlies the multiplexing system, + * which is always called by application code. */ +static void writefd_unbuffered(int fd,char *buf,size_t len) { - int total = 0; + 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) { @@ -349,11 +422,14 @@ static void writefd_unbuffered(int fd,char *buf,int len) &w_fds,NULL, &tv); + if (count == 0) { + check_timeout(); + } + if (count <= 0) { if (errno == EBADF) { exit_cleanup(RERR_SOCKETIO); } - check_timeout(); continue; } @@ -362,8 +438,8 @@ static void writefd_unbuffered(int fd,char *buf,int len) } 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) { @@ -377,7 +453,13 @@ static void writefd_unbuffered(int fd,char *buf,int len) } if (ret <= 0) { - rprintf(FERROR,"erroring writing %d bytes - exiting\n", len); + /* Don't try to write errors back + * across the stream */ + io_multiplexing_close(); + rprintf(FERROR, RSYNC_NAME + ": error writing %d unbuffered bytes" + " - exiting: %s\n", len, + strerror(errno)); exit_cleanup(RERR_STREAMIO); } @@ -419,10 +501,10 @@ void io_start_buffering(int 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, int len) +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); @@ -445,6 +527,9 @@ static void mplex_write(int fd, enum logcode code, char *buf, int len) void io_flush(void) { int fd = multiplex_out_fd; + + err_list_push(); + if (!io_buffer_count || no_flush) return; if (io_multiplexing_out) { @@ -456,8 +541,7 @@ void io_flush(void) } -/* 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) { @@ -466,28 +550,19 @@ void io_end_buffering(int fd) } } -/* some OSes have a bug where an exit causes the pending writes on - a socket to be flushed. Do an explicit shutdown to try to prevent this */ -void io_shutdown(void) -{ - if (multiplex_out_fd != -1) close(multiplex_out_fd); - if (io_error_fd != -1) close(io_error_fd); - multiplex_out_fd = -1; - io_error_fd = -1; -} - - -static void writefd(int fd,char *buf,int len) +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(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; @@ -507,6 +582,11 @@ void write_int(int f,int32 x) writefd(f,b,4); } + +/* + * 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) { extern int remote_version; @@ -524,7 +604,7 @@ void write_longint(int f, int64 x) 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); } @@ -541,14 +621,21 @@ void write_byte(int f,unsigned char c) 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; @@ -563,8 +650,6 @@ int read_line(int f, char *buf, int maxlen) return 0; } - eof_error = 1; - return 1; } @@ -576,7 +661,7 @@ void io_printf(int fd, const char *format, ...) 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); @@ -603,7 +688,7 @@ void io_start_multiplex_in(int fd) } /* write an message to the multiplexed error stream */ -int io_multiplex_write(enum logcode code, char *buf, int len) +int io_multiplex_write(enum logcode code, char *buf, size_t len) { if (!io_multiplexing_out) return 0; @@ -613,14 +698,6 @@ int io_multiplex_write(enum logcode code, char *buf, int len) return 1; } -/* write a message to the special error fd */ -int io_error_write(int f, enum logcode code, char *buf, int len) -{ - if (f == -1) return 0; - mplex_write(f, code, buf, len); - return 1; -} - /* stop output multiplexing */ void io_multiplexing_close(void) {