Add a little more protocol documentation.
[rsync/rsync.git] / io.c
diff --git a/io.c b/io.c
index 9e2a475..dac0744 100644 (file)
--- a/io.c
+++ b/io.c
@@ -1,5 +1,6 @@
-/* 
-   Copyright (C) Andrew Tridgell 1996
+/* -*- 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
@@ -18,7 +19,7 @@
 */
 
 /*
-  Utilities used in rsync 
+  socket and pipe IO utilities used in rsync 
 
   tridge, June 1996
   */
@@ -27,6 +28,8 @@
 /* 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;
@@ -37,16 +40,16 @@ extern int verbose;
 extern int io_timeout;
 extern struct stats stats;
 
-static int buffer_f_in = -1;
+static int io_error_fd = -1;
 
-void setup_readbuffer(int f_in)
-{
-       buffer_f_in = f_in;
-}
+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;
 
@@ -58,45 +61,101 @@ static void check_timeout(void)
        t = time(NULL);
 
        if (last_io && io_timeout && (t-last_io) >= io_timeout) {
-               rprintf(FERROR,"io timeout after %d second - exiting\n", 
-                       (int)(t-last_io));
+               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 char *read_buffer;
-static char *read_buffer_p;
-static int read_buffer_len;
-static int read_buffer_size;
 static int no_flush;
-static int no_flush_read;
 
-/* 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 */
+/*
+ * 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;
 
-       no_flush_read++;
        io_flush();
-       no_flush_read--;
 
        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;
 
-               if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
+               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) {
@@ -112,13 +171,25 @@ static int read_timeout(int fd, char *buf, int len)
                        continue;
                }
 
+               if (n == -1 && 
+                   (errno == EWOULDBLOCK || errno == EAGAIN)) {
+                       continue;
+               }
+
+
                if (n == 0) {
                        if (eof_error) {
-                               rprintf(FERROR,"unexpected EOF in read_timeout\n");
+                               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);
        }
@@ -144,7 +215,6 @@ static void read_loop(int fd, char *buf, int len)
 static int read_unbuffered(int fd, char *buf, int len)
 {
        static int remaining;
-       char ibuf[4];
        int tag, ret=0;
        char line[1024];
 
@@ -160,8 +230,8 @@ static int read_unbuffered(int fd, char *buf, int len)
                        continue;
                }
 
-               read_loop(fd, ibuf, 4);
-               tag = IVAL(ibuf, 0);
+               read_loop(fd, line, 4);
+               tag = IVAL(line, 0);
 
                remaining = tag & 0xFFFFFF;
                tag = tag >> 24;
@@ -184,7 +254,7 @@ static int read_unbuffered(int fd, char *buf, int len)
                read_loop(fd, line, remaining);
                line[remaining] = 0;
 
-               rprintf(tag,"%s", line);
+               rprintf((enum logcode)tag,"%s", line);
                remaining = 0;
        }
 
@@ -192,40 +262,6 @@ static int read_unbuffered(int fd, char *buf, int len)
 }
 
 
-
-/* This function was added to overcome a deadlock problem when using
- * ssh.  It looks like we can't allow our receive queue to get full or
- * ssh will clag up. Uggh.  */
-static void read_check(int f)
-{
-       int n = 8192;
-
-       if (f == -1) return;
-
-       if (read_buffer_len == 0) {
-               read_buffer_p = read_buffer;
-       }
-
-       if (n > MAX_READ_BUFFER/4)
-               n = MAX_READ_BUFFER/4;
-
-       if (read_buffer_p != read_buffer) {
-               memmove(read_buffer,read_buffer_p,read_buffer_len);
-               read_buffer_p = read_buffer;
-       }
-
-       if (n > (read_buffer_size - read_buffer_len)) {
-               read_buffer_size += n;
-               read_buffer = (char *)Realloc(read_buffer,read_buffer_size);
-               if (!read_buffer) out_of_memory("read check");      
-               read_buffer_p = read_buffer;      
-       }
-
-       n = read_unbuffered(f,read_buffer+read_buffer_len,n);
-       read_buffer_len += n;
-}
-
-
 /* 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)
@@ -233,23 +269,8 @@ static void readfd(int fd,char *buffer,int N)
        int  ret;
        int total=0;  
        
-       if ((read_buffer_len < N) && (N < 1024)) {
-               read_check(buffer_f_in);
-       }
-       
        while (total < N) {
-               if (read_buffer_len > 0 && buffer_f_in == fd) {
-                       ret = MIN(read_buffer_len,N-total);
-                       memcpy(buffer+total,read_buffer_p,ret);
-                       read_buffer_p += ret;
-                       read_buffer_len -= ret;
-                       total += ret;
-                       continue;
-               } 
-
-               no_flush_read++;
                io_flush();
-               no_flush_read--;
 
                ret = read_unbuffered(fd,buffer + total,N-total);
                total += ret;
@@ -312,18 +333,15 @@ unsigned char read_byte(int f)
        return c;
 }
 
-
-
-/* write len bytes to fd, possibly reading from buffer_f_in if set
-   in order to unclog the pipe. don't return until all len
-   bytes have been written */
+/* 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;
-       int reading=0;
+
+       err_list_push();
 
        no_flush++;
 
@@ -331,51 +349,71 @@ static void writefd_unbuffered(int fd,char *buf,int len)
                FD_ZERO(&w_fds);
                FD_ZERO(&r_fds);
                FD_SET(fd,&w_fds);
-               fd_count = fd+1;
+               fd_count = fd;
 
-               if (!no_flush_read) {
-                       reading = (buffer_f_in != -1);
-               }
-
-               if (reading) {
-                       FD_SET(buffer_f_in,&r_fds);
-                       if (buffer_f_in > fd) 
-                               fd_count = buffer_f_in+1;
+               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;
 
-               count = select(fd_count,
-                              reading?&r_fds:NULL,
+               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 (reading && FD_ISSET(buffer_f_in, &r_fds)) {
-                       read_check(buffer_f_in);
+               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;
-                       
-                       if (n > PIPE_BUF) n = PIPE_BUF;
-
-                       ret = write(fd,buf+total,n?n:1);
+                       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,"erroring writing %d bytes - exiting\n", len);
+                               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)
@@ -394,33 +432,59 @@ void io_start_buffering(int fd)
 {
        if (io_buffer) return;
        multiplex_out_fd = fd;
-       io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
+       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;
 
-       /* leave room for the multiplex header in case it's needed */
-       io_buffer += 4;
+       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) {
-               SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
-               writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
+               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-4);
+               free(io_buffer);
                io_buffer = NULL;
        }
 }
@@ -429,7 +493,9 @@ static void writefd(int fd,char *buf,int len)
 {
        stats.total_written += len;
 
-       if (!io_buffer) {
+       err_list_push();
+
+       if (!io_buffer || fd != multiplex_out_fd) {
                writefd_unbuffered(fd, buf, len);
                return;
        }
@@ -455,6 +521,11 @@ 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 +595,7 @@ 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);
@@ -547,31 +618,23 @@ void io_start_multiplex_in(int fd)
 {
        multiplex_in_fd = fd;
        io_flush();
-       if (read_buffer_len) {
-               fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
-               exit_cleanup(RERR_STREAMIO);
-       }
-
        io_multiplexing_in = 1;
 }
 
-/* write an message to the error stream */
-int io_multiplex_write(int f, char *buf, int len)
+/* 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();
-
-       SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
-       memcpy(io_buffer, buf, len);
-
        stats.total_written += (len+4);
-
-       writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
+       mplex_write(multiplex_out_fd, code, buf, len);
        return 1;
 }
 
-void io_close_input(int fd)
+/* stop output multiplexing */
+void io_multiplexing_close(void)
 {
-       buffer_f_in = -1;
+       io_multiplexing_out = 0;
 }
+