util/module.c - qemu - Git at Google

 /*
  * QEMU Module Infrastructure
  *
  * Copyright IBM, Corp. 2009
  *
  * Authors:
  *  Anthony Liguori   <aliguori@us.ibm.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2.  See
  * the COPYING file in the top-level directory.
  *
  * Contributions after 2012-01-13 are licensed under the terms of the
  * GNU GPL, version 2 or (at your option) any later version.
  */

 #include "qemu/osdep.h"
 #ifdef CONFIG_MODULES
 #include <gmodule.h>
 #endif
 #include "qemu/queue.h"
 #include "qemu/module.h"
 #include "qemu/cutils.h"
 #include "qemu/config-file.h"
 #include "qapi/error.h"
 #ifdef CONFIG_MODULE_UPGRADES
 #include "qemu-version.h"
 #endif
 #include "trace.h"

 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 bool modules_init_done[MODULE_INIT_MAX];

 static ModuleTypeList dso_init_list;

 static void init_lists(void)
 {
     static int inited;
     int i;

     if (inited) {
         return;
     }

     for (i = 0; i < MODULE_INIT_MAX; i++) {
         QTAILQ_INIT(&init_type_list[i]);
     }

     QTAILQ_INIT(&dso_init_list);

     inited = 1;
 }


 static ModuleTypeList *find_type(module_init_type type)
 {
     init_lists();

     return &init_type_list[type];
 }

 void register_module_init(void (*fn)(void), module_init_type type)
 {
     ModuleEntry *e;
     ModuleTypeList *l;

     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);
 }

 void module_call_init(module_init_type type)
 {
     ModuleTypeList *l;
     ModuleEntry *e;

     if (modules_init_done[type]) {
         return;
     }

     l = find_type(type);

     QTAILQ_FOREACH(e, l, node) {
         e->init();
     }

     modules_init_done[type] = true;
 }

 #ifdef CONFIG_MODULES

 static const QemuModinfo module_info_stub[] = { {
     /* end of list */
 } };
 static const QemuModinfo *module_info = module_info_stub;
 static const char *module_arch;

 void module_init_info(const QemuModinfo *info)
 {
     module_info = info;
 }

 void module_allow_arch(const char *arch)
 {
     module_arch = arch;
 }

 static bool module_check_arch(const QemuModinfo *modinfo)
 {
     if (modinfo->arch) {
         if (!module_arch) {
             /* no arch set -> ignore all */
             return false;
         }
         if (strcmp(module_arch, modinfo->arch) != 0) {
             /* mismatch */
             return false;
         }
     }
     return true;
 }

 /*
  * module_load_dso: attempt to load an existing dso file
  *
  * fname:          full pathname of the file to load
  * export_symbols: if true, add the symbols to the global name space
  * errp:           error to set.
  *
  * Return value:   true on success, false on error, and errp will be set.
  */
 static bool module_load_dso(const char *fname, bool export_symbols,
                             Error **errp)
 {
     GModule *g_module;
     void (*sym)(void);
     ModuleEntry *e, *next;
     int flags;

     assert(QTAILQ_EMPTY(&dso_init_list));

     flags = 0;
     if (!export_symbols) {
         flags |= G_MODULE_BIND_LOCAL;
     }
     g_module = g_module_open(fname, flags);
     if (!g_module) {
         error_setg(errp, "failed to open module: %s", g_module_error());
         return false;
     }
     if (!g_module_symbol(g_module, DSO_STAMP_FUN_STR, (gpointer *)&sym)) {
         error_setg(errp, "failed to initialize module: %s", 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)) {
             error_append_hint(errp,
                 "Only modules from the same build can be loaded.\n");
         }
         g_module_close(g_module);
         return false;
     }

     QTAILQ_FOREACH(e, &dso_init_list, node) {
         e->init();
         register_module_init(e->init, e->type);
     }
     trace_module_load_module(fname);
     QTAILQ_FOREACH_SAFE(e, &dso_init_list, node, next) {
         QTAILQ_REMOVE(&dso_init_list, e, node);
         g_free(e);
     }
     return true;
 }

 int module_load(const char *prefix, const char *name, Error **errp)
 {
     int rv = -1;
 #ifdef CONFIG_MODULE_UPGRADES
     char *version_dir;
 #endif
     const char *search_dir;
     char *dirs[5];
     char *module_name;
     int i = 0, n_dirs = 0;
     bool export_symbols = false;
     static GHashTable *loaded_modules;
     const QemuModinfo *modinfo;
     const char **sl;

     if (!g_module_supported()) {
         error_setg(errp, "%s", "this platform does not support GLib modules");
         return -1;
     }

     if (!loaded_modules) {
         loaded_modules = g_hash_table_new(g_str_hash, g_str_equal);
     }

     /* allocate all resources managed by the out: label here */
     module_name = g_strdup_printf("%s%s", prefix, name);

     if (g_hash_table_contains(loaded_modules, module_name)) {
         g_free(module_name);
         return 2; /* module already loaded */
     }
     g_hash_table_add(loaded_modules, module_name);

     search_dir = getenv("QEMU_MODULE_DIR");
     if (search_dir != NULL) {
         dirs[n_dirs++] = g_strdup_printf("%s", search_dir);
     }
     dirs[n_dirs++] = get_relocated_path(CONFIG_QEMU_MODDIR);

 #ifdef CONFIG_MODULE_UPGRADES
     version_dir = g_strcanon(g_strdup(QEMU_PKGVERSION),
                              G_CSET_A_2_Z G_CSET_a_2_z G_CSET_DIGITS "+-.~",
                              '_');
     dirs[n_dirs++] = g_strdup_printf("/var/run/qemu/%s", version_dir);
 #endif
     assert(n_dirs <= ARRAY_SIZE(dirs));

     /* end of resources managed by the out: label */

     for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
         if (modinfo->arch) {
             if (strcmp(modinfo->name, module_name) == 0) {
                 if (!module_check_arch(modinfo)) {
                     error_setg(errp, "module arch does not match: "
                         "expected '%s', got '%s'", module_arch, modinfo->arch);
                     goto out;
                 }
             }
         }
         if (modinfo->deps) {
             if (strcmp(modinfo->name, module_name) == 0) {
                 /* we depend on other module(s) */
                 for (sl = modinfo->deps; *sl != NULL; sl++) {
                     int subrv = module_load("", *sl, errp);
                     if (subrv <= 0) {
                         rv = subrv;
                         goto out;
                     }
                 }
             } else {
                 for (sl = modinfo->deps; *sl != NULL; sl++) {
                     if (strcmp(module_name, *sl) == 0) {
                         /* another module depends on us */
                         export_symbols = true;
                     }
                 }
             }
         }
     }

     for (i = 0; i < n_dirs; i++) {
         char *fname = g_strdup_printf("%s/%s%s",
                                       dirs[i], module_name, CONFIG_HOST_DSOSUF);
         int ret = access(fname, F_OK);
         if (ret != 0 && (errno == ENOENT || errno == ENOTDIR)) {
             /*
              * if we don't find the module in this dir, try the next one.
              * If we don't find it in any dir, that can be fine too: user
              * did not install the module. We will return 0 in this case
              * with no error set.
              */
             g_free(fname);
             continue;
         } else if (ret != 0) {
             /* most common is EACCES here */
             error_setg_errno(errp, errno, "error trying to access %s", fname);
         } else if (module_load_dso(fname, export_symbols, errp)) {
             rv = 1; /* module successfully loaded */
         }
         g_free(fname);
         goto out;
     }
     rv = 0; /* module not found */

 out:
     if (rv <= 0) {
         g_hash_table_remove(loaded_modules, module_name);
         g_free(module_name);
     }
     for (i = 0; i < n_dirs; i++) {
         g_free(dirs[i]);
     }
     return rv;
 }

 static bool module_loaded_qom_all;

 int module_load_qom(const char *type, Error **errp)
 {
     const QemuModinfo *modinfo;
     const char **sl;
     int rv = 0;

     if (!type) {
         error_setg(errp, "%s", "type is NULL");
         return -1;
     }

     trace_module_lookup_object_type(type);
     for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
         if (!modinfo->objs) {
             continue;
         }
         if (!module_check_arch(modinfo)) {
             continue;
         }
         for (sl = modinfo->objs; *sl != NULL; sl++) {
             if (strcmp(type, *sl) == 0) {
                 if (rv > 0) {
                     error_setg(errp, "multiple modules providing '%s'", type);
                     return -1;
                 }
                 rv = module_load("", modinfo->name, errp);
                 if (rv < 0) {
                     return rv;
                 }
             }
         }
     }
     return rv;
 }

 void module_load_qom_all(void)
 {
     const QemuModinfo *modinfo;

     if (module_loaded_qom_all) {
         return;
     }

     for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
         Error *local_err = NULL;
         if (!modinfo->objs) {
             continue;
         }
         if (!module_check_arch(modinfo)) {
             continue;
         }
         if (module_load("", modinfo->name, &local_err) < 0) {
             error_report_err(local_err);
         }
     }
     module_loaded_qom_all = true;
 }

 void qemu_load_module_for_opts(const char *group)
 {
     const QemuModinfo *modinfo;
     const char **sl;

     for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
         if (!modinfo->opts) {
             continue;
         }
         for (sl = modinfo->opts; *sl != NULL; sl++) {
             if (strcmp(group, *sl) == 0) {
                 Error *local_err = NULL;
                 if (module_load("", modinfo->name, &local_err) < 0) {
                     error_report_err(local_err);
                 }
             }
         }
     }
 }

 #else

 void module_allow_arch(const char *arch) {}
 void qemu_load_module_for_opts(const char *group) {}
 int module_load(const char *prefix, const char *name, Error **errp) { return 2; }
 int module_load_qom(const char *type, Error **errp) { return 2; }
 void module_load_qom_all(void) {}

 #endif
	/*
	* QEMU Module Infrastructure
	*
	* Copyright IBM, Corp. 2009
	*
	* Authors:
	* Anthony Liguori <aliguori@us.ibm.com>
	*
	* This work is licensed under the terms of the GNU GPL, version 2. See
	* the COPYING file in the top-level directory.
	*
	* Contributions after 2012-01-13 are licensed under the terms of the
	* GNU GPL, version 2 or (at your option) any later version.
	*/

	#include "qemu/osdep.h"
	#ifdef CONFIG_MODULES
	#include <gmodule.h>
	#endif
	#include "qemu/queue.h"
	#include "qemu/module.h"
	#include "qemu/cutils.h"
	#include "qemu/config-file.h"
	#include "qapi/error.h"
	#ifdef CONFIG_MODULE_UPGRADES
	#include "qemu-version.h"
	#endif
	#include "trace.h"

	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 bool modules_init_done[MODULE_INIT_MAX];

	static ModuleTypeList dso_init_list;

	static void init_lists(void)
	{
	static int inited;
	int i;

	if (inited) {
	return;
	}

	for (i = 0; i < MODULE_INIT_MAX; i++) {
	QTAILQ_INIT(&init_type_list[i]);
	}

	QTAILQ_INIT(&dso_init_list);

	inited = 1;
	}


	static ModuleTypeList *find_type(module_init_type type)
	{
	init_lists();

	return &init_type_list[type];
	}

	void register_module_init(void (*fn)(void), module_init_type type)
	{
	ModuleEntry *e;
	ModuleTypeList *l;

	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);
	}

	void module_call_init(module_init_type type)
	{
	ModuleTypeList *l;
	ModuleEntry *e;

	if (modules_init_done[type]) {
	return;
	}

	l = find_type(type);

	QTAILQ_FOREACH(e, l, node) {
	e->init();
	}

	modules_init_done[type] = true;
	}

	#ifdef CONFIG_MODULES

	static const QemuModinfo module_info_stub[] = { {
	/* end of list */
	} };
	static const QemuModinfo *module_info = module_info_stub;
	static const char *module_arch;

	void module_init_info(const QemuModinfo *info)
	{
	module_info = info;
	}

	void module_allow_arch(const char *arch)
	{
	module_arch = arch;
	}

	static bool module_check_arch(const QemuModinfo *modinfo)
	{
	if (modinfo->arch) {
	if (!module_arch) {
	/* no arch set -> ignore all */
	return false;
	}
	if (strcmp(module_arch, modinfo->arch) != 0) {
	/* mismatch */
	return false;
	}
	}
	return true;
	}

	/*
	* module_load_dso: attempt to load an existing dso file
	*
	* fname: full pathname of the file to load
	* export_symbols: if true, add the symbols to the global name space
	* errp: error to set.
	*
	* Return value: true on success, false on error, and errp will be set.
	*/
	static bool module_load_dso(const char *fname, bool export_symbols,
	Error **errp)
	{
	GModule *g_module;
	void (*sym)(void);
	ModuleEntry e, next;
	int flags;

	assert(QTAILQ_EMPTY(&dso_init_list));

	flags = 0;
	if (!export_symbols) {
	flags \|= G_MODULE_BIND_LOCAL;
	}
	g_module = g_module_open(fname, flags);
	if (!g_module) {
	error_setg(errp, "failed to open module: %s", g_module_error());
	return false;
	}
	if (!g_module_symbol(g_module, DSO_STAMP_FUN_STR, (gpointer *)&sym)) {
	error_setg(errp, "failed to initialize module: %s", 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)) {
	error_append_hint(errp,
	"Only modules from the same build can be loaded.\n");
	}
	g_module_close(g_module);
	return false;
	}

	QTAILQ_FOREACH(e, &dso_init_list, node) {
	e->init();
	register_module_init(e->init, e->type);
	}
	trace_module_load_module(fname);
	QTAILQ_FOREACH_SAFE(e, &dso_init_list, node, next) {
	QTAILQ_REMOVE(&dso_init_list, e, node);
	g_free(e);
	}
	return true;
	}

	int module_load(const char prefix, const char name, Error **errp)
	{
	int rv = -1;
	#ifdef CONFIG_MODULE_UPGRADES
	char *version_dir;
	#endif
	const char *search_dir;
	char *dirs[5];
	char *module_name;
	int i = 0, n_dirs = 0;
	bool export_symbols = false;
	static GHashTable *loaded_modules;
	const QemuModinfo *modinfo;
	const char **sl;

	if (!g_module_supported()) {
	error_setg(errp, "%s", "this platform does not support GLib modules");
	return -1;
	}

	if (!loaded_modules) {
	loaded_modules = g_hash_table_new(g_str_hash, g_str_equal);
	}

	/* allocate all resources managed by the out: label here */
	module_name = g_strdup_printf("%s%s", prefix, name);

	if (g_hash_table_contains(loaded_modules, module_name)) {
	g_free(module_name);
	return 2; /* module already loaded */
	}
	g_hash_table_add(loaded_modules, module_name);

	search_dir = getenv("QEMU_MODULE_DIR");
	if (search_dir != NULL) {
	dirs[n_dirs++] = g_strdup_printf("%s", search_dir);
	}
	dirs[n_dirs++] = get_relocated_path(CONFIG_QEMU_MODDIR);

	#ifdef CONFIG_MODULE_UPGRADES
	version_dir = g_strcanon(g_strdup(QEMU_PKGVERSION),
	G_CSET_A_2_Z G_CSET_a_2_z G_CSET_DIGITS "+-.~",
	'_');
	dirs[n_dirs++] = g_strdup_printf("/var/run/qemu/%s", version_dir);
	#endif
	assert(n_dirs <= ARRAY_SIZE(dirs));

	/* end of resources managed by the out: label */

	for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
	if (modinfo->arch) {
	if (strcmp(modinfo->name, module_name) == 0) {
	if (!module_check_arch(modinfo)) {
	error_setg(errp, "module arch does not match: "
	"expected '%s', got '%s'", module_arch, modinfo->arch);
	goto out;
	}
	}
	}
	if (modinfo->deps) {
	if (strcmp(modinfo->name, module_name) == 0) {
	/* we depend on other module(s) */
	for (sl = modinfo->deps; *sl != NULL; sl++) {
	int subrv = module_load("", *sl, errp);
	if (subrv <= 0) {
	rv = subrv;
	goto out;
	}
	}
	} else {
	for (sl = modinfo->deps; *sl != NULL; sl++) {
	if (strcmp(module_name, *sl) == 0) {
	/* another module depends on us */
	export_symbols = true;
	}
	}
	}
	}
	}

	for (i = 0; i < n_dirs; i++) {
	char *fname = g_strdup_printf("%s/%s%s",
	dirs[i], module_name, CONFIG_HOST_DSOSUF);
	int ret = access(fname, F_OK);
	if (ret != 0 && (errno == ENOENT \|\| errno == ENOTDIR)) {
	/*
	* if we don't find the module in this dir, try the next one.
	* If we don't find it in any dir, that can be fine too: user
	* did not install the module. We will return 0 in this case
	* with no error set.
	*/
	g_free(fname);
	continue;
	} else if (ret != 0) {
	/* most common is EACCES here */
	error_setg_errno(errp, errno, "error trying to access %s", fname);
	} else if (module_load_dso(fname, export_symbols, errp)) {
	rv = 1; /* module successfully loaded */
	}
	g_free(fname);
	goto out;
	}
	rv = 0; /* module not found */

	out:
	if (rv <= 0) {
	g_hash_table_remove(loaded_modules, module_name);
	g_free(module_name);
	}
	for (i = 0; i < n_dirs; i++) {
	g_free(dirs[i]);
	}
	return rv;
	}

	static bool module_loaded_qom_all;

	int module_load_qom(const char type, Error *errp)
	{
	const QemuModinfo *modinfo;
	const char **sl;
	int rv = 0;

	if (!type) {
	error_setg(errp, "%s", "type is NULL");
	return -1;
	}

	trace_module_lookup_object_type(type);
	for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
	if (!modinfo->objs) {
	continue;
	}
	if (!module_check_arch(modinfo)) {
	continue;
	}
	for (sl = modinfo->objs; *sl != NULL; sl++) {
	if (strcmp(type, *sl) == 0) {
	if (rv > 0) {
	error_setg(errp, "multiple modules providing '%s'", type);
	return -1;
	}
	rv = module_load("", modinfo->name, errp);
	if (rv < 0) {
	return rv;
	}
	}
	}
	}
	return rv;
	}

	void module_load_qom_all(void)
	{
	const QemuModinfo *modinfo;

	if (module_loaded_qom_all) {
	return;
	}

	for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
	Error *local_err = NULL;
	if (!modinfo->objs) {
	continue;
	}
	if (!module_check_arch(modinfo)) {
	continue;
	}
	if (module_load("", modinfo->name, &local_err) < 0) {
	error_report_err(local_err);
	}
	}
	module_loaded_qom_all = true;
	}

	void qemu_load_module_for_opts(const char *group)
	{
	const QemuModinfo *modinfo;
	const char **sl;

	for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
	if (!modinfo->opts) {
	continue;
	}
	for (sl = modinfo->opts; *sl != NULL; sl++) {
	if (strcmp(group, *sl) == 0) {
	Error *local_err = NULL;
	if (module_load("", modinfo->name, &local_err) < 0) {
	error_report_err(local_err);
	}
	}
	}
	}
	}

	#else

	void module_allow_arch(const char *arch) {}
	void qemu_load_module_for_opts(const char *group) {}
	int module_load(const char prefix, const char name, Error **errp) { return 2; }
	int module_load_qom(const char type, Error *errp) { return 2; }
	void module_load_qom_all(void) {}

	#endif