From e26110cfc67d48331a76e9b1e6f7fed7569e1ab3 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Mon, 10 Feb 2014 14:48:57 +0800 Subject: [PATCH] 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 Signed-off-by: Fam Zheng Signed-off-by: Paolo Bonzini --- Makefile | 3 + configure | 42 +++++++++--- include/qemu/module.h | 23 ++++++- module-common.c | 10 +++ rules.mak | 3 + scripts/create_config | 3 + util/module.c | 145 +++++++++++++++++++++++++++++++++++++++++- 7 files changed, 217 insertions(+), 12 deletions(-) create mode 100644 module-common.c diff --git a/Makefile b/Makefile index 9d53117832..07d1ed7d83 100644 --- a/Makefile +++ b/Makefile @@ -201,6 +201,9 @@ Makefile: $(version-obj-y) $(version-lobj-y) libqemustub.a: $(stub-obj-y) libqemuutil.a: $(util-obj-y) qapi-types.o qapi-visit.o +block-modules = $(foreach o,$(block-obj-m),"$(basename $(subst /,-,$o))",) NULL +util/module.o-cflags = -D'CONFIG_BLOCK_MODULES=$(block-modules)' + ###################################################################### qemu-img.o: qemu-img-cmds.h diff --git a/configure b/configure index e3bc04eb19..136a8f0b1b 100755 --- a/configure +++ b/configure @@ -1137,7 +1137,7 @@ Advanced options (experts only): --libdir=PATH install libraries in PATH --sysconfdir=PATH install config in PATH$confsuffix --localstatedir=PATH install local state in PATH (set at runtime on win32) - --with-confsuffix=SUFFIX suffix for QEMU data inside datadir and sysconfdir [$confsuffix] + --with-confsuffix=SUFFIX suffix for QEMU data inside datadir/libdir/sysconfdir [$confsuffix] --enable-modules enable modules support --enable-debug-tcg enable TCG debugging --disable-debug-tcg disable TCG debugging (default) @@ -2362,14 +2362,32 @@ if test "$mingw32" = yes; then else glib_req_ver=2.12 fi -if $pkg_config --atleast-version=$glib_req_ver gthread-2.0; then - glib_cflags=`$pkg_config --cflags gthread-2.0` - glib_libs=`$pkg_config --libs gthread-2.0` - CFLAGS="$glib_cflags $CFLAGS" - LIBS="$glib_libs $LIBS" - libs_qga="$glib_libs $libs_qga" -else - error_exit "glib-$glib_req_ver required to compile QEMU" + +for i in gthread-2.0 gmodule-2.0; do + if $pkg_config --atleast-version=$glib_req_ver $i; then + glib_cflags=`$pkg_config --cflags $i` + glib_libs=`$pkg_config --libs $i` + CFLAGS="$glib_cflags $CFLAGS" + LIBS="$glib_libs $LIBS" + libs_qga="$glib_libs $libs_qga" + else + error_exit "glib-$glib_req_ver $i is required to compile QEMU" + fi +done + +########################################## +# SHA command probe for modules +if test "$modules" = yes; then + shacmd_probe="sha1sum sha1 shasum" + for c in $shacmd_probe; do + if which $c &>/dev/null; then + shacmd="$c" + break + fi + done + if test "$shacmd" = ""; then + error_exit "one of the checksum commands is required to enable modules: $shacmd_probe" + fi fi ########################################## @@ -3661,6 +3679,7 @@ if test "$mingw32" = "yes" ; then fi qemu_confdir=$sysconfdir$confsuffix +qemu_moddir=$libdir$confsuffix qemu_datadir=$datadir$confsuffix qemu_localedir="$datadir/locale" @@ -3751,6 +3770,7 @@ echo "Install prefix $prefix" echo "BIOS directory `eval echo $qemu_datadir`" echo "binary directory `eval echo $bindir`" echo "library directory `eval echo $libdir`" +echo "module directory `eval echo $qemu_moddir`" echo "libexec directory `eval echo $libexecdir`" echo "include directory `eval echo $includedir`" echo "config directory `eval echo $sysconfdir`" @@ -3890,6 +3910,7 @@ echo "sysconfdir=$sysconfdir" >> $config_host_mak echo "qemu_confdir=$qemu_confdir" >> $config_host_mak echo "qemu_datadir=$qemu_datadir" >> $config_host_mak echo "qemu_docdir=$qemu_docdir" >> $config_host_mak +echo "qemu_moddir=$qemu_moddir" >> $config_host_mak if test "$mingw32" = "no" ; then echo "qemu_localstatedir=$local_statedir" >> $config_host_mak fi @@ -4023,6 +4044,9 @@ if [ "$docs" = "yes" ] ; then echo "BUILD_DOCS=yes" >> $config_host_mak fi if test "$modules" = "yes"; then + # $shacmd can generate a hash started with digit, which the compiler doesn't + # like as an symbol. So prefix it with an underscore + echo "CONFIG_STAMP=_`(echo $qemu_version; echo $pkgversion; cat $0) | $shacmd - | cut -f1 -d\ `" >> $config_host_mak echo "CONFIG_MODULES=y" >> $config_host_mak fi if test "$sdl" = "yes" ; then diff --git a/include/qemu/module.h b/include/qemu/module.h index c4ccd57166..72d94984a2 100644 --- a/include/qemu/module.h +++ b/include/qemu/module.h @@ -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); diff --git a/module-common.c b/module-common.c new file mode 100644 index 0000000000..50c67500b1 --- /dev/null +++ b/module-common.c @@ -0,0 +1,10 @@ +#include "config-host.h" +#include "qemu/module.h" + +void qemu_module_dummy(void) +{ +} + +void DSO_STAMP_FUN(void) +{ +} diff --git a/rules.mak b/rules.mak index 0abf3d1f36..9dda9f760f 100644 --- a/rules.mak +++ b/rules.mak @@ -82,6 +82,8 @@ DSO_CFLAGS := -fPIC -DBUILD_DSO %$(DSOSUF): LDFLAGS += $(LDFLAGS_SHARED) %$(DSOSUF): %.mo libqemustub.a $(call LINK,$^) + @# Copy to build root so modules can be loaded when program started without install + $(if $(findstring /,$@),$(call quiet-command,cp $@ $(subst /,-,$@), " CP $(subst /,-,$@)")) .PHONY: modules modules: @@ -211,6 +213,7 @@ $(foreach o,$(filter %.o,$($1)), $(eval $(patsubst %.o,%.mo,$o): $o) \ $(eval $(patsubst %.o,%.mo,$o)-objs := $o)) $(foreach o,$(filter-out $(modules-m), $(patsubst %.o,%.mo,$($1))), \ + $(eval $o-objs += module-common.o) $(eval $o: $($o-objs)) $(eval modules-objs-m += $($o-objs)) $(eval modules-m += $o) diff --git a/scripts/create_config b/scripts/create_config index 06f5316d9d..546f889144 100755 --- a/scripts/create_config +++ b/scripts/create_config @@ -108,6 +108,9 @@ case $line in value=${line#*=} echo "#define $name $value" ;; + DSOSUF=*) + echo "#define HOST_DSOSUF \"${line#*=}\"" + ;; esac done # read diff --git a/util/module.c b/util/module.c index 7acc33d076..42bc3732c9 100644 --- a/util/module.c +++ b/util/module.c @@ -13,6 +13,8 @@ * GNU GPL, version 2 or (at your option) any later version. */ +#include +#include #include "qemu-common.h" #include "qemu/queue.h" #include "qemu/module.h" @@ -21,13 +23,16 @@ typedef struct ModuleEntry { void (*init)(void); QTAILQ_ENTRY(ModuleEntry) node; + module_init_type type; } ModuleEntry; typedef QTAILQ_HEAD(, ModuleEntry) ModuleTypeList; static ModuleTypeList init_type_list[MODULE_INIT_MAX]; -static void init_types(void) +static ModuleTypeList dso_init_list; + +static void init_lists(void) { static int inited; int i; @@ -40,6 +45,8 @@ static void init_types(void) QTAILQ_INIT(&init_type_list[i]); } + QTAILQ_INIT(&dso_init_list); + inited = 1; } @@ -48,7 +55,7 @@ static ModuleTypeList *find_type(module_init_type type) { ModuleTypeList *l; - init_types(); + init_lists(); l = &init_type_list[type]; @@ -62,20 +69,154 @@ void register_module_init(void (*fn)(void), module_init_type type) e = g_malloc0(sizeof(*e)); e->init = fn; + e->type = type; l = find_type(type); QTAILQ_INSERT_TAIL(l, e, node); } +void register_dso_module_init(void (*fn)(void), module_init_type type) +{ + ModuleEntry *e; + + init_lists(); + + e = g_malloc0(sizeof(*e)); + e->init = fn; + e->type = type; + + QTAILQ_INSERT_TAIL(&dso_init_list, e, node); +} + +static void module_load(module_init_type type); + void module_call_init(module_init_type type) { ModuleTypeList *l; ModuleEntry *e; + module_load(type); l = find_type(type); QTAILQ_FOREACH(e, l, node) { e->init(); } } + +#ifdef CONFIG_MODULES +static int module_load_file(const char *fname) +{ + GModule *g_module; + void (*sym)(void); + const char *dsosuf = HOST_DSOSUF; + int len = strlen(fname); + int suf_len = strlen(dsosuf); + ModuleEntry *e, *next; + int ret; + + if (len <= suf_len || strcmp(&fname[len - suf_len], dsosuf)) { + /* wrong suffix */ + ret = -EINVAL; + goto out; + } + if (access(fname, F_OK)) { + ret = -ENOENT; + goto out; + } + + assert(QTAILQ_EMPTY(&dso_init_list)); + + g_module = g_module_open(fname, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL); + if (!g_module) { + fprintf(stderr, "Failed to open module: %s\n", + g_module_error()); + ret = -EINVAL; + goto out; + } + if (!g_module_symbol(g_module, DSO_STAMP_FUN_STR, (gpointer *)&sym)) { + fprintf(stderr, "Failed to initialize module: %s\n", + fname); + /* Print some info if this is a QEMU module (but from different build), + * this will make debugging user problems easier. */ + if (g_module_symbol(g_module, "qemu_module_dummy", (gpointer *)&sym)) { + fprintf(stderr, + "Note: only modules from the same build can be loaded.\n"); + } + g_module_close(g_module); + ret = -EINVAL; + } else { + QTAILQ_FOREACH(e, &dso_init_list, node) { + register_module_init(e->init, e->type); + } + ret = 0; + } + + QTAILQ_FOREACH_SAFE(e, &dso_init_list, node, next) { + QTAILQ_REMOVE(&dso_init_list, e, node); + g_free(e); + } +out: + return ret; +} +#endif + +void module_load(module_init_type type) +{ +#ifdef CONFIG_MODULES + char *fname = NULL; + const char **mp; + static const char *block_modules[] = { + CONFIG_BLOCK_MODULES + }; + char *exec_dir; + char *dirs[3]; + int i = 0; + int ret; + + if (!g_module_supported()) { + fprintf(stderr, "Module is not supported by system.\n"); + return; + } + + switch (type) { + case MODULE_INIT_BLOCK: + mp = block_modules; + break; + default: + /* no other types have dynamic modules for now*/ + return; + } + + exec_dir = qemu_get_exec_dir(); + dirs[i++] = g_strdup_printf("%s", CONFIG_QEMU_MODDIR); + dirs[i++] = g_strdup_printf("%s/..", exec_dir ? : ""); + dirs[i++] = g_strdup_printf("%s", exec_dir ? : ""); + assert(i == ARRAY_SIZE(dirs)); + g_free(exec_dir); + exec_dir = NULL; + + for ( ; *mp; mp++) { + for (i = 0; i < ARRAY_SIZE(dirs); i++) { + fname = g_strdup_printf("%s/%s%s", dirs[i], *mp, HOST_DSOSUF); + ret = module_load_file(fname); + /* Try loading until loaded a module file */ + if (!ret) { + break; + } + g_free(fname); + fname = NULL; + } + if (ret == -ENOENT) { + fprintf(stderr, "Can't find module: %s\n", *mp); + } + + g_free(fname); + } + + for (i = 0; i < ARRAY_SIZE(dirs); i++) { + g_free(dirs[i]); + } + +#endif +} -- 2.39.5