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Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading |
Date: |
Mon, 16 Sep 2013 09:59:02 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Sep 16, 2013 at 02:50:24PM +0800, Fam Zheng wrote:
> Added three types of modules:
>
> typedef enum {
> MODULE_LOAD_BLOCK = 0,
> MODULE_LOAD_UI,
> MODULE_LOAD_NET,
> MODULE_LOAD_MAX,
> } module_load_type;
>
> and their loading function:
>
> void module_load(module_load_type).
>
> which loads whitelisted ".so" files of the given type under ${MODDIR}.
>
> Modules of each type should be loaded in respective subsystem
> initialization code.
>
> The init function of dynamic module is no longer with
> __attribute__((constructor)) as static linked version, and need to be
> explicitly called once loaded. The function name is mangled with per
> configure fingerprint as:
>
> init_$(date +%s$$$RANDOM)
>
> Which is known to module_load function, and the loading fails if this
> symbol is not there. With this, modules built from a different
> tree/version/configure will not be loaded.
>
> The module loading code requires gmodule-2.0.
>
> Configure option "--enable-modules=L" can be used to restrict qemu to
> only build/load some whitelisted modules.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> Makefile | 3 ++
> block.c | 1 +
> configure | 44 +++++++++++++++++++++-------
> include/qemu/module.h | 23 +++++++++++++++
> rules.mak | 9 ++++--
> scripts/create_config | 22 ++++++++++++++
> util/module.c | 81
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> vl.c | 2 ++
> 8 files changed, 172 insertions(+), 13 deletions(-)
>
> +void module_load(module_load_type type)
> +{
> +#ifdef CONFIG_MODULES
> + const char *prefix;
> + char *fname = NULL;
> + const char **mp;
> + static const char *module_whitelist[] = {
> + CONFIG_MODULE_WHITELIST
> + };
> +
> + if (!g_module_supported()) {
> + return;
> + }
> +
> + switch (type) {
> + case MODULE_LOAD_BLOCK:
> + prefix = "block-";
> + break;
> + case MODULE_LOAD_UI:
> + prefix = "ui-";
> + break;
> + case MODULE_LOAD_NET:
> + prefix = "ui-";
Wrong prefix.
> + break;
> + default:
> + return;
> + }
> +
> + for (mp = &module_whitelist[0]; *mp; mp++) {
> + if (strncmp(prefix, *mp, strlen(prefix))) {
> + continue;
> + }
> + fname = g_strdup_printf("%s/%s%s", CONFIG_MODDIR, *mp, HOST_DSOSUF);
> + module_load_file(fname);
> + g_free(fname);
> + }
> +
> +#endif
> +}
IMHO this method design is really crazy. If you want to have a
situation where you call module_load() multiple times, then
have separate whitelists for block/net/ui, instead of having
one global whitelist which you then have to load a subset of
each time. Alternatively just call module_load() once and
give rid of these enums for loading block/net/ui separately.
Daniel
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- [Qemu-devel] [PATCH v10 0/8] Shared Library Module Support, Fam Zheng, 2013/09/16
- [Qemu-devel] [PATCH v10 1/8] ui/Makefile.objs: delete unnecessary cocoa.o dependency, Fam Zheng, 2013/09/16
- [Qemu-devel] [PATCH v10 2/8] make.rule: fix $(obj) to a real relative path, Fam Zheng, 2013/09/16
- [Qemu-devel] [PATCH v10 3/8] rule.mak: allow per object cflags and libs, Fam Zheng, 2013/09/16
- [Qemu-devel] [PATCH v10 4/8] build-sys: introduce common-obj-m and block-obj-m for DSO, Fam Zheng, 2013/09/16
- [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Fam Zheng, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading,
Daniel P. Berrange <=
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Paolo Bonzini, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Fam Zheng, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Paolo Bonzini, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Daniel P. Berrange, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Paolo Bonzini, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Daniel P. Berrange, 2013/09/16
- Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading, Paolo Bonzini, 2013/09/16