0587568780
The way we get QMP commands registered is high tech:
* qapi-commands.py generates qmp_init_marshal() that does the actual work
* it also generates the magic to register it as a MODULE_INIT_QAPI
function, so it runs when someone calls
module_call_init(MODULE_INIT_QAPI)
* main() calls module_call_init()
QEMU needs to register a few non-qapified commands. Same high tech
works: monitor.c has its own qmp_init_marshal() along with the magic
to make it run in module_call_init(MODULE_INIT_QAPI).
QEMU also needs to unregister commands that are not wanted in this
build's configuration (commit 5032a16). Simple enough:
qmp_unregister_commands_hack(). The difficulty is to make it run
after the generated qmp_init_marshal(). We can't simply run it in
monitor.c's qmp_init_marshal(), because the order in which the
registered functions run is indeterminate. So qmp_init_marshal()
registers qmp_unregister_commands_hack() separately. Since
registering *appends* to the list of registered functions, this will
make it run after all the functions that have been registered already.
I suspect it takes a long and expensive computer science education to
not find this silly.
Dumb it down as follows:
* Drop MODULE_INIT_QAPI entirely
* Give the generated qmp_init_marshal() external linkage.
* Call it instead of module_call_init(MODULE_INIT_QAPI)
* Except in QEMU proper, call new monitor_init_qmp_commands() that in
turn calls the generated qmp_init_marshal(), registers the
additional commands and unregisters the unwanted ones.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1488544368-30622-5-git-send-email-armbru@redhat.com>
64 lines
2.1 KiB
C
64 lines
2.1 KiB
C
/*
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* QEMU Module Infrastructure
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*
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* Copyright IBM, Corp. 2009
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#ifndef QEMU_MODULE_H
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#define QEMU_MODULE_H
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#define DSO_STAMP_FUN glue(qemu_stamp, CONFIG_STAMP)
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#define DSO_STAMP_FUN_STR stringify(DSO_STAMP_FUN)
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#ifdef BUILD_DSO
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void DSO_STAMP_FUN(void);
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/* This is a dummy symbol to identify a loaded DSO as a QEMU module, so we can
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* distinguish "version mismatch" from "not a QEMU module", when the stamp
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* check fails during module loading */
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void qemu_module_dummy(void);
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#define module_init(function, type) \
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static void __attribute__((constructor)) do_qemu_init_ ## function(void) \
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{ \
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register_dso_module_init(function, type); \
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}
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#else
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/* This should not be used directly. Use block_init etc. instead. */
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#define module_init(function, type) \
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static void __attribute__((constructor)) do_qemu_init_ ## function(void) \
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{ \
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register_module_init(function, type); \
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}
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#endif
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typedef enum {
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MODULE_INIT_BLOCK,
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MODULE_INIT_OPTS,
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MODULE_INIT_QOM,
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MODULE_INIT_TRACE,
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MODULE_INIT_MAX
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} module_init_type;
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#define block_init(function) module_init(function, MODULE_INIT_BLOCK)
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#define opts_init(function) module_init(function, MODULE_INIT_OPTS)
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#define type_init(function) module_init(function, MODULE_INIT_QOM)
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#define trace_init(function) module_init(function, MODULE_INIT_TRACE)
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#define block_module_load_one(lib) module_load_one("block-", lib)
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void register_module_init(void (*fn)(void), module_init_type type);
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void register_dso_module_init(void (*fn)(void), module_init_type type);
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void module_call_init(module_init_type type);
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void module_load_one(const char *prefix, const char *lib_name);
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#endif
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