module: implement module loading

This patch adds loading, stamp checking and initialization of modules.

The init function of dynamic module is no longer directly called as
__attribute__((constructor)) in static linked version, it is called
only after passed the checking of presense of stamp symbol:

    qemu_stamp_$RELEASEHASH

where $RELEASEHASH is generated by hashing version strings and content
of configure script.

With this, modules built from a different tree/version/configure will
not be loaded.

The module loading code requires gmodule-2.0.

Modules are searched under
 - CONFIG_MODDIR
 - executable folder (to allow running qemu-{img,io} in the build
   directory)
 - ../ of executable folder (to allow running system emulator in the
   build directory)

Modules are linked under their subdir respectively, then copied to top
level of build directory for above convinience, e.g.:
    $(BUILD_DIR)/block/curl.so -> $(BUILD_DIR)/block-curl.so

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Fam Zheng 2014-02-10 14:48:57 +08:00 committed by Paolo Bonzini
parent 17969268f5
commit e26110cfc6
7 changed files with 217 additions and 12 deletions

View file

@ -14,11 +14,31 @@
#ifndef QEMU_MODULE_H
#define QEMU_MODULE_H
#include "qemu/osdep.h"
#define DSO_STAMP_FUN glue(qemu_stamp, CONFIG_STAMP)
#define DSO_STAMP_FUN_STR stringify(DSO_STAMP_FUN)
#ifdef BUILD_DSO
void DSO_STAMP_FUN(void);
/* This is a dummy symbol to identify a loaded DSO as a QEMU module, so we can
* distinguish "version mismatch" from "not a QEMU module", when the stamp
* check fails during module loading */
void qemu_module_dummy(void);
#define module_init(function, type) \
static void __attribute__((constructor)) do_qemu_init_ ## function(void) \
{ \
register_dso_module_init(function, type); \
}
#else
/* This should not be used directly. Use block_init etc. instead. */
#define module_init(function, type) \
static void __attribute__((constructor)) do_qemu_init_ ## function(void) { \
static void __attribute__((constructor)) do_qemu_init_ ## function(void) \
{ \
register_module_init(function, type); \
}
#endif
typedef enum {
MODULE_INIT_BLOCK,
@ -34,6 +54,7 @@ typedef enum {
#define type_init(function) module_init(function, MODULE_INIT_QOM)
void register_module_init(void (*fn)(void), module_init_type type);
void register_dso_module_init(void (*fn)(void), module_init_type type);
void module_call_init(module_init_type type);