switch to using socketpair instead of pipe if possible. This fixes the
[rsync/rsync.git] / io.c
diff --git a/io.c b/io.c
index 9e2d379..6f3854e 100644 (file)
--- a/io.c
+++ b/io.c
@@ -18,7 +18,7 @@
 */
 
 /*
-  Utilities used in rsync 
+  socket and pipe IO utilities used in rsync 
 
   tridge, June 1996
   */
@@ -38,6 +38,7 @@ 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)
 {
@@ -64,13 +65,30 @@ static void check_timeout(void)
        }
 }
 
+/* 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 FERROR */
+static void read_error_fd(void)
+{
+       char buf[200];
+       int n;
+       int fd = io_error_fd;
+       io_error_fd = -1;
+
+       n = read(fd, buf, sizeof(buf)-1);
+       if (n > 0) {
+               rwrite(FERROR, buf, 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
@@ -79,24 +97,39 @@ 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) {
@@ -112,6 +145,7 @@ static int read_timeout(int fd, char *buf, int len)
                        continue;
                }
 
+
                if (n == 0) {
                        if (eof_error) {
                                rprintf(FERROR,"unexpected EOF in read_timeout\n");
@@ -119,6 +153,9 @@ static int read_timeout(int fd, char *buf, int len)
                        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);
        }
@@ -192,40 +229,6 @@ 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 +236,8 @@ 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;
@@ -323,7 +311,6 @@ static void writefd_unbuffered(int fd,char *buf,int len)
        fd_set w_fds, r_fds;
        int fd_count, count;
        struct timeval tv;
-       int reading=0;
 
        no_flush++;
 
@@ -331,38 +318,42 @@ 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 n = len-total;
-                       int ret = write(fd,buf+total,n?n:1);
+                       int ret, n = len-total;
+                       
+                       if (n > PIPE_BUF) n = PIPE_BUF;
+
+                       ret = write(fd,buf+total,n?n:1);
 
                        if (ret == -1 && errno == EINTR) {
                                continue;
@@ -426,7 +417,7 @@ static void writefd(int fd,char *buf,int len)
 {
        stats.total_written += len;
 
-       if (!io_buffer) {
+       if (!io_buffer || fd != multiplex_out_fd) {
                writefd_unbuffered(fd, buf, len);
                return;
        }
@@ -544,15 +535,10 @@ 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 */
+/* write an message to the multiplexed error stream */
 int io_multiplex_write(int f, char *buf, int len)
 {
        if (!io_multiplexing_out) return 0;
@@ -568,6 +554,20 @@ int io_multiplex_write(int f, char *buf, int len)
        return 1;
 }
 
+/* write a message to the special error fd */
+int io_error_write(int f, char *buf, int len)
+{
+       if (f == -1) return 0;
+       writefd_unbuffered(f, buf, len);
+       return 1;
+}
+
+/* stop output multiplexing */
+void io_multiplexing_close(void)
+{
+       io_multiplexing_out = 0;
+}
+
 void io_close_input(int fd)
 {
        buffer_f_in = -1;