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authorFam Zheng <famz@redhat.com>2014-02-10 14:48:57 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2014-02-20 13:14:18 +0100
commite26110cfc67d48331a76e9b1e6f7fed7569e1ab3 (patch)
tree9ac70ad405cdf18189017345ee184f268510db3b /util
parent17969268f5938ae1d7f3dedbd73e507badb6146d (diff)
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>
Diffstat (limited to 'util')
-rw-r--r--util/module.c145
1 files changed, 143 insertions, 2 deletions
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 <stdlib.h>
+#include <gmodule.h>
#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
+}