X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/914cc65c9d751c6dd812e9cf8bd2d3169e288921..eca2adb4b3a4ca095116f54e9e0a6df19f0bd149:/io.c diff --git a/io.c b/io.c index ed6a70c3..a83276d5 100644 --- a/io.c +++ b/io.c @@ -1,23 +1,23 @@ /* -*- 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. -*/ + * + * 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 @@ -36,7 +36,7 @@ #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 static int io_multiplexing_out; @@ -52,6 +52,19 @@ 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; @@ -86,13 +99,13 @@ 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]; @@ -124,21 +137,18 @@ static void read_error_fd(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. + */ 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 { @@ -163,7 +173,7 @@ static void die_from_readerr (int err) } -/*! +/** * 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. * @@ -245,8 +255,10 @@ static int read_timeout (int fd, char *buf, size_t len) -/*! Continue trying to read len bytes - don't return until len has - been read. */ +/** + * 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) { @@ -316,8 +328,11 @@ static int read_unbuffered(int fd, char *buf, size_t 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 */ +/** + * 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; @@ -387,8 +402,40 @@ unsigned char read_byte(int f) return c; } -/* Write len bytes to fd. This underlies the multiplexing system, - * which is always called by application code. */ + +/** + * 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; @@ -457,24 +504,13 @@ static void writefd_unbuffered(int fd,char *buf,size_t len) * across the stream */ io_multiplexing_close(); rprintf(FERROR, RSYNC_NAME - ": error writing %d unbuffered bytes" - " - exiting: %s\n", len, + ": 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; @@ -499,8 +535,10 @@ void io_start_buffering(int fd) io_buffer_count = 0; } -/* write an message to a multiplexed stream. If this fails then rsync - exits */ +/** + * 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]; @@ -609,7 +647,7 @@ 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)); @@ -670,7 +708,7 @@ void io_printf(int fd, const char *format, ...) } -/* 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; @@ -679,7 +717,7 @@ void io_start_multiplex_out(int 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; @@ -687,7 +725,7 @@ void io_start_multiplex_in(int fd) io_multiplexing_in = 1; } -/* write an message to the multiplexed error stream */ +/** 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; @@ -698,7 +736,7 @@ int io_multiplex_write(enum logcode code, char *buf, size_t len) return 1; } -/* stop output multiplexing */ +/** Stop output multiplexing */ void io_multiplexing_close(void) { io_multiplexing_out = 0;