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[rsync.git] / io.c

/* -*- 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.
*/

/*
  socket and pipe IO utilities used in rsync 

  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;
extern int verbose;
extern int io_timeout;
extern struct stats stats;

static int io_error_fd = -1;

static void read_loop(int fd, char *buf, int 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 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 */
static void read_error_fd(void)
{
        char buf[200];
        int 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;
}


static int no_flush;

/*
 * 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, int len)
{
        int n, ret=0;

        io_flush();

        while (ret == 0) {
                fd_set fds;
                struct timeval tv;
                int fd_count = fd+1;

                FD_ZERO(&fds);
                FD_SET(fd, &fds);
                if (io_error_fd != -1) {
                        FD_SET(io_error_fd, &fds);
                        if (io_error_fd > fd) fd_count = io_error_fd+1;
                }

                tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
                tv.tv_usec = 0;

                errno = 0;

                if (select(fd_count, &fds, NULL, NULL, &tv) < 1) {
                        if (errno == EBADF) {
                                exit_cleanup(RERR_SOCKETIO);
                        }
                        check_timeout();
                        continue;
                }

                if (io_error_fd != -1 && FD_ISSET(io_error_fd, &fds)) {
                        read_error_fd();
                }

                if (!FD_ISSET(fd, &fds)) continue;

                n = read(fd, buf, len);

                if (n > 0) {
                        buf += n;
                        len -= n;
                        ret += n;
                        if (io_timeout)
                                last_io = time(NULL);
                        continue;
                }

                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)
{
        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 return <= 0 */
static int read_unbuffered(int fd, char *buf, int len)
{
        static int remaining;
        int tag, ret=0;
        char line[1024];

        if (!io_multiplexing_in || fd != multiplex_in_fd) 
                return read_timeout(fd, buf, len);

        while (ret == 0) {
                if (remaining) {
                        len = MIN(len, remaining);
                        read_loop(fd, buf, len);
                        remaining -= len;
                        ret = len;
                        continue;
                }

                read_loop(fd, line, 4);
                tag = IVAL(line, 0);

                remaining = tag & 0xFFFFFF;
                tag = tag >> 24;

                if (tag == MPLEX_BASE) 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 %d\n\n", 
                                remaining);
                        exit_cleanup(RERR_STREAMIO);
                }

                read_loop(fd, line, remaining);
                line[remaining] = 0;

                rprintf((enum logcode)tag,"%s", line);
                remaining = 0;
        }

        return ret;
}


/* 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)
{
        int  ret;
        int total=0;  
        
        while (total < N) {
                io_flush();

                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)
{
        extern int remote_version;
        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
        if (remote_version >= 16) {
                readfd(f,b,8);
                ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
        }
#endif

        return ret;
}

void read_buf(int f,char *buf,int len)
{
        readfd(f,buf,len);
}

void read_sbuf(int f,char *buf,int 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;
}

/* write len bytes to fd */
static void writefd_unbuffered(int fd,char *buf,int len)
{
        int 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_ZERO(&r_fds);
                FD_SET(fd,&w_fds);
                fd_count = fd;

                if (io_error_fd != -1) {
                        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) {
                        if (errno == EBADF) {
                                exit_cleanup(RERR_SOCKETIO);
                        }
                        check_timeout();
                        continue;
                }

                if (io_error_fd != -1 && FD_ISSET(io_error_fd, &r_fds)) {
                        read_error_fd();
                }

                if (FD_ISSET(fd, &w_fds)) {
                        int ret, 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) {
                                rprintf(FERROR,
                                        "error writing %d unbuffered bytes"
                                        " - exiting: %s\n", len,
                                        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);
                        }
 
                        total += ret;

                        if (io_timeout)
                                last_io = time(NULL);
                }
        }

        no_flush--;
}


static char *io_buffer;
static int io_buffer_count;

void io_start_buffering(int fd)
{
        if (io_buffer) return;
        multiplex_out_fd = fd;
        io_buffer = (char *)malloc(IO_BUFFER_SIZE);
        if (!io_buffer) out_of_memory("writefd");
        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)
{
        char buffer[4096];
        int 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;
}


/* XXX: fd is ignored, which seems a little strange. */
void io_end_buffering(int fd)
{
        io_flush();
        if (!io_multiplexing_out) {
                free(io_buffer);
                io_buffer = NULL;
        }
}

static void writefd(int fd,char *buf,int 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);
                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);
}


/*
 * 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;
        char b[8];

        if (remote_version < 16 || x <= 0x7FFFFFFF) {
                write_int(f, (int)x);
                return;
        }

        write_int(f, (int32)0xFFFFFFFF);
        SIVAL(b,0,(x&0xFFFFFFFF));
        SIVAL(b,4,((x>>32)&0xFFFFFFFF));

        writefd(f,b,8);
}

void write_buf(int f,char *buf,int 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);
}

int read_line(int f, char *buf, int maxlen)
{
        eof_error = 0;

        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;
        }

        eof_error = 1;

        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(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, int 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;
}