Remove main loop.

This commit removes the external main loop, which never worked
and caused a number of bugs.  Requests are now done synchronously,
and if the user wants to have requests issued in the background
or to have a responsive GUI, then they'll just have to use threads.

The big change is to push all reads and writes through two
functions called send_to_daemon (for writes) and recv_from_daemon
(for reads) which operate synchronously.  These functions
read/write whole messages, and also handle checking for EOF
(ie. daemon died) and asynchronous log message events from
qemu (eg. from debug / dmesg printed by the guest).  A more
complete description of how these work can be found in the code.

This code passes a complete run of the tests.

Bugs believed to be fixed by this commit:

  https://bugzilla.redhat.com/show_bug.cgi?id=501888
  internal error: reply callback called twice

  https://bugzilla.redhat.com/show_bug.cgi?id=504418
  In virt-inspector: "download: guestfs_download reply failed, see earlier error messages"

I have tried to avoid reintroducing this:

  https://bugzilla.redhat.com/show_bug.cgi?id=508713
  libguestfs: error: write: Broken pipe (guestfish only)

One other benefit of this is that 'set_busy/end_busy' calls
no longer appear in traces.

1 files changed, 10 insertions, 50 deletions

diff --git a/src/guestfs.h b/src/guestfs.h
index 6412a53c..35f995d1 100644
--- a/src/guestfs.h
+++ b/src/guestfs.h
@@ -31,7 +31,6 @@ extern "C" {
 #endif
 
 typedef struct guestfs_h guestfs_h;
-typedef struct guestfs_main_loop guestfs_main_loop;
 
 /* Connection management. */
 extern guestfs_h *guestfs_create (void);
@@ -52,19 +51,18 @@ extern guestfs_abort_cb guestfs_get_out_of_memory_handler (guestfs_h *g);
 #include <guestfs-structs.h>
 #include <guestfs-actions.h>
 
-/* Low-level event API. */
-typedef void (*guestfs_send_cb) (guestfs_h *g, void *data);
-typedef void (*guestfs_reply_cb) (guestfs_h *g, void *data, XDR *xdr);
+/* Events. */
 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);
 
-extern void guestfs_set_send_callback (guestfs_h *g, guestfs_send_cb cb, void *opaque);
-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);
 extern void guestfs_set_subprocess_quit_callback (guestfs_h *g, guestfs_subprocess_quit_cb cb, void *opaque);
 extern void guestfs_set_launch_done_callback (guestfs_h *g, guestfs_launch_done_cb cb, void *opaque);
 
+/* Private, for use only by the actions. */
+struct guestfs_message_header;
+struct guestfs_message_error;
 extern void guestfs_error (guestfs_h *g, const char *fs, ...)
   __attribute__((format (printf,2,3)));
 extern void guestfs_perrorf (guestfs_h *g, const char *fs, ...)
@@ -74,50 +72,12 @@ extern void *guestfs_safe_calloc (guestfs_h *g, size_t n, size_t s);
 extern void *guestfs_safe_realloc (guestfs_h *g, void *ptr, int nbytes);
 extern char *guestfs_safe_strdup (guestfs_h *g, const char *str);
 extern void *guestfs_safe_memdup (guestfs_h *g, void *ptr, size_t size);
-
-extern int guestfs__switch_to_sending (guestfs_h *g);
-extern int guestfs__switch_to_receiving (guestfs_h *g);
-
-/* These *_sync calls wait until the action is performed, using the
- * main loop.  We should implement asynchronous versions too.
- */
-extern int guestfs__send_sync (guestfs_h *g, int proc_nr, xdrproc_t xdrp, char *args);
-extern int guestfs__send_file_sync (guestfs_h *g, const char *filename);
-extern int guestfs__receive_file_sync (guestfs_h *g, const char *filename);
-
-/* Main loop. */
-#define GUESTFS_HANDLE_READABLE 0x1
-#define GUESTFS_HANDLE_WRITABLE 0x2
-#define GUESTFS_HANDLE_HANGUP   0x4
-#define GUESTFS_HANDLE_ERROR    0x8
-
-typedef void (*guestfs_handle_event_cb) (guestfs_main_loop *ml, guestfs_h *g, void *data, int watch, int fd, int events);
-typedef int (*guestfs_add_handle_cb) (guestfs_main_loop *ml, guestfs_h *g, int fd, int events, guestfs_handle_event_cb cb, void *data);
-typedef int (*guestfs_remove_handle_cb) (guestfs_main_loop *ml, guestfs_h *g, int watch);
-typedef void (*guestfs_handle_timeout_cb) (guestfs_main_loop *ml, guestfs_h *g, void *data, int timer);
-typedef int (*guestfs_add_timeout_cb) (guestfs_main_loop *ml, guestfs_h *g, int interval, guestfs_handle_timeout_cb cb, void *data);
-typedef int (*guestfs_remove_timeout_cb) (guestfs_main_loop *ml, guestfs_h *g, int timer);
-typedef int (*guestfs_main_loop_run_cb) (guestfs_main_loop *ml, guestfs_h *g);
-typedef int (*guestfs_main_loop_quit_cb) (guestfs_main_loop *ml, guestfs_h *g);
-
-/* This is the head of the main loop structure.  Concrete implementations
- * use additional private data after this struct.
- */
-struct guestfs_main_loop {
-  guestfs_add_handle_cb add_handle;
-  guestfs_remove_handle_cb remove_handle;
-  guestfs_add_timeout_cb add_timeout;
-  guestfs_remove_timeout_cb remove_timeout;
-  guestfs_main_loop_run_cb main_loop_run;
-  guestfs_main_loop_quit_cb main_loop_quit;
-};
-
-extern void guestfs_set_main_loop (guestfs_h *handle, guestfs_main_loop *main_loop);
-extern guestfs_main_loop *guestfs_get_main_loop (guestfs_h *handle);
-extern guestfs_main_loop *guestfs_get_default_main_loop (void);
-
-extern guestfs_main_loop *guestfs_create_main_loop (void);
-extern void guestfs_free_main_loop (guestfs_main_loop *);
+extern int guestfs___set_busy (guestfs_h *g);
+extern int guestfs___end_busy (guestfs_h *g);
+extern int guestfs___send (guestfs_h *g, int proc_nr, xdrproc_t xdrp, char *args);
+extern int guestfs___recv (guestfs_h *g, const char *fn, struct guestfs_message_header *hdr, struct guestfs_message_error *err, xdrproc_t xdrp, char *ret);
+extern int guestfs___send_file (guestfs_h *g, const char *filename);
+extern int guestfs___recv_file (guestfs_h *g, const char *filename);
 
 #ifdef __cplusplus
 }