Code to handle the daemon communications socket.

3 files changed, 123 insertions, 8 deletions

diff --git a/guestfs.pod b/guestfs.pod
index 9202fb84..b0fa5f29 100644
--- a/guestfs.pod
+++ b/guestfs.pod
@@ -417,9 +417,9 @@ For example:
    /* returns immediately */
  }
  
- my_cb (guestfs_h *handle, void *data)
+ my_cb (guestfs_h *handle, void *data, XDR *xdr)
  {
-   retval = guestfs_nb_[action]_r (handle);
+   retval = guestfs_nb_[action]_r (handle, xdr);
    /* ... */
  }
 
@@ -429,6 +429,7 @@ high-level API.
 
 =head2 guestfs_set_reply_callback
 
+ typedef void (*guestfs_reply_cb) (guestfs_h *g, void *opaque, XDR *xdr);
  void guestfs_set_reply_callback (guestfs_h *handle,
                                   guestfs_reply_cb cb,
                                   void *opaque);
@@ -439,6 +440,8 @@ from the BUSY state to the READY state).
 
 =head2 guestfs_set_log_message_callback
 
+ typedef void (*guestfs_log_message_cb) (guestfs_h *g, void *opaque,
+                                         char *buf, int len);
  void guestfs_set_log_message_callback (guestfs_h *handle,
                                         guestfs_log_message_cb cb,
                                         void *opaque);
@@ -453,6 +456,7 @@ discarded.
 
 =head2 guestfs_set_subprocess_quit_callback
 
+ typedef void (*guestfs_subprocess_quit_cb) (guestfs_h *g, void *opaque);
  void guestfs_set_subprocess_quit_callback (guestfs_h *handle,
                                             guestfs_subprocess_quit_cb cb,
                                             void *opaque);
@@ -464,6 +468,7 @@ any state to the CONFIG state).
 
 =head2 guestfs_set_launch_done_callback
 
+ typedef void (*guestfs_launch_done_cb) (guestfs_h *g, void *opaque);
  void guestfs_set_launch_done_callback (guestfs_h *handle,
                                         guestfs_ready_cb cb,
                                         void *opaque);
diff --git a/src/guestfs.c b/src/guestfs.c
index a827157b..7e883035 100644
--- a/src/guestfs.c
+++ b/src/guestfs.c
@@ -29,6 +29,9 @@
 #include <string.h>
 #include <fcntl.h>
 #include <time.h>
+#include <sys/select.h>
+#include <rpc/types.h>
+#include <rpc/xdr.h>
 
 #ifdef HAVE_ERRNO_H
 #include <errno.h>
@@ -50,8 +53,6 @@
 #include <sys/un.h>
 #endif
 
-#include <sys/select.h>
-
 #include "guestfs.h"
 
 static void error (guestfs_h *g, const char *fs, ...);
@@ -131,6 +132,12 @@ struct guestfs_h
   void *                     reply_cb_internal_data;
   guestfs_launch_done_cb     launch_done_cb_internal;
   void *                     launch_done_cb_internal_data;
+
+  /* Messages sent and received from the daemon. */
+  char *msg_in;
+  int msg_in_size, msg_in_allocated;
+  char *msg_out;
+  int msg_out_size;
 };
 
 guestfs_h *
@@ -206,7 +213,7 @@ guestfs_close (guestfs_h *g)
 static void
 default_error_cb (guestfs_h *g, void *data, const char *msg)
 {
-  fprintf (stderr, "libguestfs: %s\n", msg);
+  fprintf (stderr, "libguestfs: error: %s\n", msg);
 }
 
 static void
@@ -445,6 +452,7 @@ guestfs_launch (guestfs_h *g)
   }
 
   snprintf (unixsock, sizeof unixsock, "%s/sock", g->tmpdir);
+  unlink (unixsock);
 
   if (pipe (wfd) == -1 || pipe (rfd) == -1) {
     perrorf (g, "pipe");
@@ -587,6 +595,14 @@ guestfs_launch (guestfs_h *g)
 
  connected:
   /* Watch the file descriptors. */
+  free (g->msg_in);
+  g->msg_in = NULL;
+  g->msg_in_size = g->msg_in_allocated = 0;
+
+  free (g->msg_out);
+  g->msg_out = NULL;
+  g->msg_out_size = 0;
+
   g->stdout_watch =
     main_loop.add_handle (g, g->fd[1],
 			  GUESTFS_HANDLE_READABLE,
@@ -769,14 +785,106 @@ stdout_event (void *data, int watch, int fd, int events)
 static void
 sock_read_event (void *data, int watch, int fd, int events)
 {
-  /*guestfs_h *g = (guestfs_h *) data;*/
+  guestfs_h *g = (guestfs_h *) data;
+  XDR xdr;
+  unsigned len;
+  int n;
+
+  if (g->verbose)
+    fprintf (stderr,
+	     "sock_event: %p g->state = %d, fd = %d, events = 0x%x\n",
+	     g, g->state, fd, events);
+
+  if (g->sock != fd) {
+    error (g, "sock_read_event: internal error: %d != %d", g->sock, fd);
+    return;
+  }
+
+  if (g->msg_in_size <= g->msg_in_allocated) {
+    g->msg_in_allocated += 4096;
+    g->msg_in = safe_realloc (g, g->msg_in, g->msg_in_allocated);
+  }
+  n = read (g->sock, g->msg_in + g->msg_in_size,
+	    g->msg_in_allocated - g->msg_in_size);
+  if (n == 0)
+    /* Disconnected?  Ignore it because stdout_watch will get called
+     * and will do the cleanup.
+     */
+    return;
 
+  if (n == -1) {
+    if (errno != EAGAIN)
+      perrorf (g, "read");
+    return;
+  }
 
+  g->msg_in_size += n;
 
+  /* Have we got enough of a message to be able to process it yet? */
+  if (g->msg_in_size < 4) return;
 
+  xdrmem_create (&xdr, g->msg_in, g->msg_in_size, XDR_DECODE);
+  if (!xdr_uint32_t (&xdr, &len)) {
+    error (g, "can't decode length word");
+    goto cleanup;
+  }
 
+  /* Length is normally the length of the message, but when guestfsd
+   * starts up it sends a "magic" value (longer than any possible
+   * message).  Check for this.
+   */
+  if (len == 0xf5f5f5f5) {
+    if (g->state != LAUNCHING)
+      error (g, "received magic signature from guestfsd, but in state %d",
+	     g->state);
+    else if (g->msg_in_size != 4)
+      error (g, "received magic signature from guestfsd, but msg size is %d",
+	     g->msg_in_size);
+    else {
+      g->state = READY;
+      if (g->launch_done_cb_internal)
+	g->launch_done_cb_internal (g, g->launch_done_cb_internal_data);
+      if (g->launch_done_cb)
+	g->launch_done_cb (g, g->launch_done_cb_data);
+    }
+
+    goto cleanup;
+  }
+
+  if (g->msg_in_size < len) return; /* Need more of this message. */
 
+  /* This should not happen, and if it does it probably means we've
+   * lost all hope of synchronization.
+   */
+  if (g->msg_in_size > len) {
+    error (g, "len = %d, but msg_in_size = %d", len, g->msg_in_size);
+    goto cleanup;
+  }
 
+  /* Not in the expected state. */
+  if (g->state != BUSY)
+    error (g, "state %d != BUSY", g->state);
+
+  /* Push the message up to the higher layer.  Note that unlike
+   * launch_done_cb / launch_done_cb_internal, we only call at
+   * most one of the callback functions here.
+   */
+  g->state = READY;
+  if (g->reply_cb_internal)
+    g->reply_cb_internal (g, g->reply_cb_internal_data, &xdr);
+  else if (g->reply_cb)
+    g->reply_cb (g, g->reply_cb, &xdr);
+
+ cleanup:
+  /* Free the message buffer if it's grown excessively large. */
+  if (g->msg_in_allocated > 65536) {
+    free (g->msg_in);
+    g->msg_in = NULL;
+    g->msg_in_size = g->msg_in_allocated = 0;
+  } else
+    g->msg_in_size = 0;
+
+  xdr_destroy (&xdr);
 }
 
 /* This is the default main loop implementation, using select(2). */
diff --git a/src/guestfs.h b/src/guestfs.h
index ead53072..4e032c66 100644
--- a/src/guestfs.h
+++ b/src/guestfs.h
@@ -24,6 +24,8 @@
  * Go and read it now, I'll wait.
  */
 
+#include <rpc/xdr.h>
+
 typedef struct guestfs_h guestfs_h;
 
 /* Connection management. */
@@ -56,10 +58,10 @@ extern int guestfs_get_verbose (guestfs_h *g);
 extern int guestfs_sync (guestfs_h *g);
 
 /* Low-level event API. */
-typedef void (*guestfs_reply_cb) (guestfs_h *g, void *data /* , ... */);
+typedef void (*guestfs_reply_cb) (guestfs_h *g, void *data, XDR *xdr);
 typedef void (*guestfs_log_message_cb) (guestfs_h *g, void *data, char *buf, int len);
 typedef void (*guestfs_subprocess_quit_cb) (guestfs_h *g, void *data);
-typedef void (*guestfs_launch_done_cb) (guestfs_h *g, void *data /* , ... */);
+typedef void (*guestfs_launch_done_cb) (guestfs_h *g, void *data);
 
 extern void guestfs_set_reply_callback (guestfs_h *g, guestfs_reply_cb cb, void *opaque);
 extern void guestfs_set_log_message_callback (guestfs_h *g, guestfs_log_message_cb cb, void *opaque);