/* $NetBSD: kern_module.c,v 1.37 2008/12/05 12:55:09 ad Exp $ */ /*- * Copyright (c) 2008 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software developed for The NetBSD Foundation * by Andrew Doran. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Kernel module support. */ #include __KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.37 2008/12/05 12:55:09 ad Exp $"); #ifdef _KERNEL_OPT #include "opt_ddb.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct vm_map *module_map; struct modlist module_list = TAILQ_HEAD_INITIALIZER(module_list); struct modlist module_bootlist = TAILQ_HEAD_INITIALIZER(module_bootlist); static module_t *module_active; static char module_base[64]; static int module_verbose_on; static int module_autoload_on = 1; u_int module_count; kmutex_t module_lock; u_int module_autotime = 10; u_int module_gen = 1; static kcondvar_t module_thread_cv; static kmutex_t module_thread_lock; static int module_thread_ticks; /* Ensure that the kernel's link set isn't empty. */ static modinfo_t module_dummy; __link_set_add_rodata(modules, module_dummy); static module_t *module_lookup(const char *); static int module_do_load(const char *, bool, int, prop_dictionary_t, module_t **, modclass_t class, bool); static int module_do_unload(const char *); static void module_error(const char *, ...); static void module_print(const char *, ...); static int module_do_builtin(const char *, module_t **); static int module_fetch_info(module_t *); static void module_thread(void *); /* * module_error: * * Utility function: log an error. */ static void module_error(const char *fmt, ...) { va_list ap; va_start(ap, fmt); printf("WARNING: module error: "); vprintf(fmt, ap); printf("\n"); va_end(ap); } /* * module_print: * * Utility function: log verbose output. */ static void module_print(const char *fmt, ...) { va_list ap; if (module_verbose_on) { va_start(ap, fmt); printf("DEBUG: module: "); vprintf(fmt, ap); printf("\n"); va_end(ap); } } /* * module_init: * * Initialize the module subsystem. */ void module_init(void) { extern struct vm_map *module_map; int error; if (module_map == NULL) { module_map = kernel_map; } mutex_init(&module_lock, MUTEX_DEFAULT, IPL_NONE); cv_init(&module_thread_cv, "modunload"); mutex_init(&module_thread_lock, MUTEX_DEFAULT, IPL_NONE); #ifdef MODULAR /* XXX */ module_init_md(); #endif #if __NetBSD_Version__ / 1000000 % 100 == 99 /* -current */ snprintf(module_base, sizeof(module_base), "/stand/%s/%s/modules", machine, osrelease); #else /* release */ snprintf(module_base, sizeof(module_base), "/stand/%s/%d.%d/modules", machine, __NetBSD_Version__ / 100000000, __NetBSD_Version__ / 1000000 % 100); #endif error = kthread_create(PRI_VM, KTHREAD_MPSAFE, NULL, module_thread, NULL, NULL, "modunload"); if (error != 0) panic("module_init: %d", error); } SYSCTL_SETUP(sysctl_module_setup, "sysctl module setup") { const struct sysctlnode *node = NULL; sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "kern", NULL, NULL, 0, NULL, 0, CTL_KERN, CTL_EOL); sysctl_createv(clog, 0, NULL, &node, CTLFLAG_PERMANENT, CTLTYPE_NODE, "module", SYSCTL_DESCR("Module options"), NULL, 0, NULL, 0, CTL_KERN, CTL_CREATE, CTL_EOL); if (node == NULL) return; sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "autoload", SYSCTL_DESCR("Enable automatic load of modules"), NULL, 0, &module_autoload_on, 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "verbose", SYSCTL_DESCR("Enable verbose output"), NULL, 0, &module_verbose_on, 0, CTL_CREATE, CTL_EOL); } /* * module_init_class: * * Initialize all built-in and pre-loaded modules of the * specified class. */ void module_init_class(modclass_t class) { __link_set_decl(modules, modinfo_t); modinfo_t *const *mip, *mi; module_t *mod; mutex_enter(&module_lock); /* * Builtins first. These can't depend on pre-loaded modules. */ __link_set_foreach(mip, modules) { mi = *mip; if (mi == &module_dummy) { continue; } if (class != MODULE_CLASS_ANY && class != mi->mi_class) { continue; } (void)module_do_builtin(mi->mi_name, NULL); } /* * Now preloaded modules. These will be pulled off the * list as we call module_do_load(); */ do { TAILQ_FOREACH(mod, &module_bootlist, mod_chain) { mi = mod->mod_info; if (class != MODULE_CLASS_ANY && class != mi->mi_class) continue; module_do_load(mi->mi_name, false, 0, NULL, NULL, class, true); break; } } while (mod != NULL); mutex_exit(&module_lock); } /* * module_compatible: * * Return true if the two supplied kernel versions are said to * have the same binary interface for kernel code. The entire * version is signficant for the development tree (-current), * major and minor versions are significant for official * releases of the system. */ bool module_compatible(int v1, int v2) { #if __NetBSD_Version__ / 1000000 % 100 == 99 /* -current */ return v1 == v2; #else /* release */ return abs(v1 - v2) < 10000; #endif } /* * module_load: * * Load a single module from the file system. */ int module_load(const char *filename, int flags, prop_dictionary_t props, modclass_t class) { int error; /* Authorize. */ error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE, 0, (void *)(uintptr_t)MODCTL_LOAD, NULL, NULL); if (error != 0) { return error; } mutex_enter(&module_lock); error = module_do_load(filename, false, flags, props, NULL, class, false); mutex_exit(&module_lock); return error; } /* * module_autoload: * * Load a single module from the file system, system initiated. */ int module_autoload(const char *filename, modclass_t class) { int error; KASSERT(mutex_owned(&module_lock)); /* Nothing if the user has disabled it. */ if (!module_autoload_on) { return EPERM; } /* Disallow path seperators and magic symlinks. */ if (strchr(filename, '/') != NULL || strchr(filename, '@') != NULL || strchr(filename, '.') != NULL) { return EPERM; } /* Authorize. */ error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE, 0, (void *)(uintptr_t)MODCTL_LOAD, (void *)(uintptr_t)1, NULL); if (error != 0) { return error; } return module_do_load(filename, false, 0, NULL, NULL, class, true); } /* * module_unload: * * Find and unload a module by name. */ int module_unload(const char *name) { int error; /* Authorize. */ error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE, 0, (void *)(uintptr_t)MODCTL_UNLOAD, NULL, NULL); if (error != 0) { return error; } mutex_enter(&module_lock); error = module_do_unload(name); mutex_exit(&module_lock); return error; } /* * module_lookup: * * Look up a module by name. */ module_t * module_lookup(const char *name) { module_t *mod; KASSERT(mutex_owned(&module_lock)); TAILQ_FOREACH(mod, &module_list, mod_chain) { if (strcmp(mod->mod_info->mi_name, name) == 0) { break; } } return mod; } /* * module_hold: * * Add a single reference to a module. It's the caller's * responsibility to ensure that the reference is dropped * later. */ int module_hold(const char *name) { module_t *mod; mutex_enter(&module_lock); mod = module_lookup(name); if (mod == NULL) { mutex_exit(&module_lock); return ENOENT; } mod->mod_refcnt++; mutex_exit(&module_lock); return 0; } /* * module_rele: * * Release a reference acquired with module_hold(). */ void module_rele(const char *name) { module_t *mod; mutex_enter(&module_lock); mod = module_lookup(name); if (mod == NULL) { mutex_exit(&module_lock); panic("module_rele: gone"); } mod->mod_refcnt--; mutex_exit(&module_lock); } /* * module_enqueue: * * Put a module onto the global list and update counters. */ static void module_enqueue(module_t *mod) { int i; /* * If there are requisite modules, put at the head of the queue. * This is so that autounload can unload requisite modules with * only one pass through the queue. */ if (mod->mod_nrequired) { TAILQ_INSERT_HEAD(&module_list, mod, mod_chain); /* Add references to the requisite modules. */ for (i = 0; i < mod->mod_nrequired; i++) { KASSERT(mod->mod_required[i] != NULL); mod->mod_required[i]->mod_refcnt++; } } else { TAILQ_INSERT_TAIL(&module_list, mod, mod_chain); } module_count++; module_gen++; } /* * module_do_builtin: * * Initialize a single module from the list of modules that are * built into the kernel (linked into the kernel image). */ static int module_do_builtin(const char *name, module_t **modp) { __link_set_decl(modules, modinfo_t); modinfo_t *const *mip; const char *p, *s; char buf[MAXMODNAME]; modinfo_t *mi; module_t *mod, *mod2; size_t len; int error; KASSERT(mutex_owned(&module_lock)); /* * Check to see if already loaded. */ if ((mod = module_lookup(name)) != NULL) { if (modp != NULL) { *modp = mod; } return 0; } /* * Search the list to see if we have a module by this name. */ error = ENOENT; __link_set_foreach(mip, modules) { mi = *mip; if (mi == &module_dummy) { continue; } if (strcmp(mi->mi_name, name) == 0) { error = 0; break; } } if (error != 0) { return error; } /* * Initialize pre-requisites. */ mod = kmem_zalloc(sizeof(*mod), KM_SLEEP); if (mod == NULL) { return ENOMEM; } if (modp != NULL) { *modp = mod; } if (mi->mi_required != NULL) { for (s = mi->mi_required; *s != '\0'; s = p) { if (*s == ',') s++; p = s; while (*p != '\0' && *p != ',') p++; len = min(p - s + 1, sizeof(buf)); strlcpy(buf, s, len); if (buf[0] == '\0') break; if (mod->mod_nrequired == MAXMODDEPS - 1) { module_error("too many required modules"); kmem_free(mod, sizeof(*mod)); return EINVAL; } error = module_do_builtin(buf, &mod2); if (error != 0) { kmem_free(mod, sizeof(*mod)); return error; } mod->mod_required[mod->mod_nrequired++] = mod2; } } /* * Try to initialize the module. */ KASSERT(module_active == NULL); module_active = mod; error = (*mi->mi_modcmd)(MODULE_CMD_INIT, NULL); module_active = NULL; if (error != 0) { module_error("builtin module `%s' " "failed to init", mi->mi_name); kmem_free(mod, sizeof(*mod)); return error; } mod->mod_info = mi; mod->mod_source = MODULE_SOURCE_KERNEL; module_enqueue(mod); return 0; } /* * module_do_load: * * Helper routine: load a module from the file system, or one * pushed by the boot loader. */ static int module_do_load(const char *name, bool isdep, int flags, prop_dictionary_t props, module_t **modp, modclass_t class, bool autoload) { static TAILQ_HEAD(,module) pending = TAILQ_HEAD_INITIALIZER(pending); static int depth; const int maxdepth = 6; modinfo_t *mi; module_t *mod, *mod2; char buf[MAXMODNAME]; const char *s, *p; int error; size_t len; KASSERT(mutex_owned(&module_lock)); error = 0; /* * Avoid recursing too far. */ if (++depth > maxdepth) { module_error("too many required modules"); depth--; return EMLINK; } /* * Load the module and link. Before going to the file system, * scan the list of modules loaded by the boot loader. Just * before init is started the list of modules loaded at boot * will be purged. Before init is started we can assume that * `name' is a module name and not a path name. */ TAILQ_FOREACH(mod, &module_bootlist, mod_chain) { if (strcmp(mod->mod_info->mi_name, name) == 0) { TAILQ_REMOVE(&module_bootlist, mod, mod_chain); break; } } if (mod != NULL) { TAILQ_INSERT_TAIL(&pending, mod, mod_chain); } else { /* * If a requisite module, check to see if it is * already present. */ if (isdep) { TAILQ_FOREACH(mod, &module_list, mod_chain) { if (strcmp(mod->mod_info->mi_name, name) == 0) { break; } } if (mod != NULL) { if (modp != NULL) { *modp = mod; } depth--; return 0; } } mod = kmem_zalloc(sizeof(*mod), KM_SLEEP); if (mod == NULL) { depth--; return ENOMEM; } error = kobj_load_file(&mod->mod_kobj, name, module_base, autoload); if (error != 0) { kmem_free(mod, sizeof(*mod)); depth--; if (autoload) { module_print("Cannot load kernel object `%s'" " error=%d", name, error); } else { module_error("Cannot load kernel object `%s'" " error=%d", name, error); } return error; } TAILQ_INSERT_TAIL(&pending, mod, mod_chain); mod->mod_source = MODULE_SOURCE_FILESYS; error = module_fetch_info(mod); if (error != 0) { module_error("cannot fetch module info for `%s'", name); goto fail; } } /* * Check compatibility. */ mi = mod->mod_info; if (strlen(mi->mi_name) >= MAXMODNAME) { error = EINVAL; module_error("module name `%s' too long", mi->mi_name); goto fail; } if (!module_compatible(mi->mi_version, __NetBSD_Version__)) { module_error("module built for `%d', system `%d'", mi->mi_version, __NetBSD_Version__); if ((flags & MODCTL_LOAD_FORCE) != 0) { module_error("forced load, system may be unstable"); } else { error = EPROGMISMATCH; goto fail; } } /* * If a specific kind of module was requested, ensure that we have * a match. */ if (class != MODULE_CLASS_ANY && class != mi->mi_class) { module_print("incompatible module class for `%s' (%d != %d)", name, class, mi->mi_class); error = ENOENT; goto fail; } /* * If loading a dependency, `name' is a plain module name. * The name must match. */ if (isdep && strcmp(mi->mi_name, name) != 0) { module_error("dependency name mismatch (`%s' != `%s')", name, mi->mi_name); error = ENOENT; goto fail; } /* * Check to see if the module is already loaded. If so, we may * have been recursively called to handle a dependency, so be sure * to set modp. */ if ((mod2 = module_lookup(mi->mi_name)) != NULL) { if (modp != NULL) *modp = mod2; module_print("module `%s' already loaded", mi->mi_name); error = EEXIST; goto fail; } /* * Block circular dependencies. */ TAILQ_FOREACH(mod2, &pending, mod_chain) { if (mod == mod2) { continue; } if (strcmp(mod2->mod_info->mi_name, mi->mi_name) == 0) { error = EDEADLK; module_error("circular dependency detected for `%s'", mi->mi_name); goto fail; } } /* * Now try to load any requisite modules. */ if (mi->mi_required != NULL) { for (s = mi->mi_required; *s != '\0'; s = p) { if (*s == ',') s++; p = s; while (*p != '\0' && *p != ',') p++; len = p - s + 1; if (len >= MAXMODNAME) { error = EINVAL; module_error("required module name `%s'" " too long", mi->mi_required); goto fail; } strlcpy(buf, s, len); if (buf[0] == '\0') break; if (mod->mod_nrequired == MAXMODDEPS - 1) { error = EINVAL; module_error("too many required modules (%d)", mod->mod_nrequired); goto fail; } if (strcmp(buf, mi->mi_name) == 0) { error = EDEADLK; module_error("self-dependency detected for " "`%s'", mi->mi_name); goto fail; } error = module_do_load(buf, true, flags, NULL, &mod->mod_required[mod->mod_nrequired++], MODULE_CLASS_ANY, true); if (error != 0) goto fail; } } /* * We loaded all needed modules successfully: perform global * relocations and initialize. */ error = kobj_affix(mod->mod_kobj, mi->mi_name); if (error != 0) { /* Cannot touch 'mi' as the module is now gone. */ module_error("unable to affix module `%s'", name); goto fail2; } KASSERT(module_active == NULL); module_active = mod; error = (*mi->mi_modcmd)(MODULE_CMD_INIT, props); module_active = NULL; if (error != 0) { module_error("modcmd function returned error %d for `%s'", error, mi->mi_name); goto fail; } /* * Good, the module loaded successfully. Put it onto the * list and add references to its requisite modules. */ TAILQ_REMOVE(&pending, mod, mod_chain); module_enqueue(mod); if (modp != NULL) { *modp = mod; } if (autoload) { /* * Arrange to try unloading the module after * a short delay. */ mod->mod_autotime = time_second + module_autotime; module_thread_kick(); } depth--; return 0; fail: kobj_unload(mod->mod_kobj); fail2: TAILQ_REMOVE(&pending, mod, mod_chain); kmem_free(mod, sizeof(*mod)); depth--; return error; } /* * module_do_unload: * * Helper routine: do the dirty work of unloading a module. */ static int module_do_unload(const char *name) { module_t *mod; int error; u_int i; KASSERT(mutex_owned(&module_lock)); mod = module_lookup(name); if (mod == NULL) { module_error("module `%s' not found", name); return ENOENT; } if (mod->mod_refcnt != 0 || mod->mod_source == MODULE_SOURCE_KERNEL) { module_print("module `%s' busy", name); return EBUSY; } KASSERT(module_active == NULL); module_active = mod; error = (*mod->mod_info->mi_modcmd)(MODULE_CMD_FINI, NULL); module_active = NULL; if (error != 0) { module_print("cannot unload module `%s' error=%d", name, error); return error; } module_count--; TAILQ_REMOVE(&module_list, mod, mod_chain); for (i = 0; i < mod->mod_nrequired; i++) { mod->mod_required[i]->mod_refcnt--; } if (mod->mod_kobj != NULL) { kobj_unload(mod->mod_kobj); } kmem_free(mod, sizeof(*mod)); module_gen++; return 0; } /* * module_prime: * * Push a module loaded by the bootloader onto our internal * list. */ int module_prime(void *base, size_t size) { module_t *mod; int error; mod = kmem_zalloc(sizeof(*mod), KM_SLEEP); if (mod == NULL) { return ENOMEM; } mod->mod_source = MODULE_SOURCE_BOOT; error = kobj_load_mem(&mod->mod_kobj, base, size); if (error != 0) { kmem_free(mod, sizeof(*mod)); module_error("unable to load object pushed by boot loader"); return error; } error = module_fetch_info(mod); if (error != 0) { kobj_unload(mod->mod_kobj); kmem_free(mod, sizeof(*mod)); module_error("unable to load object pushed by boot loader"); return error; } TAILQ_INSERT_TAIL(&module_bootlist, mod, mod_chain); return 0; } /* * module_fetch_into: * * Fetch modinfo record from a loaded module. */ static int module_fetch_info(module_t *mod) { int error; void *addr; size_t size; /* * Find module info record and check compatibility. */ error = kobj_find_section(mod->mod_kobj, "link_set_modules", &addr, &size); if (error != 0) { module_error("`link_set_modules' section not present"); return error; } if (size != sizeof(modinfo_t **)) { module_error("`link_set_modules' section wrong size"); return error; } mod->mod_info = *(modinfo_t **)addr; return 0; } /* * module_find_section: * * Allows a module that is being initialized to look up a section * within its ELF object. */ int module_find_section(const char *name, void **addr, size_t *size) { KASSERT(mutex_owned(&module_lock)); KASSERT(module_active != NULL); return kobj_find_section(module_active->mod_kobj, name, addr, size); } /* * module_thread: * * Automatically unload modules. We try once to unload autoloaded * modules after module_autotime seconds. If the system is under * severe memory pressure, we'll try unloading all modules. */ static void module_thread(void *cookie) { module_t *mod, *next; modinfo_t *mi; int error; for (;;) { mutex_enter(&module_lock); for (mod = TAILQ_FIRST(&module_list); mod != NULL; mod = next) { next = TAILQ_NEXT(mod, mod_chain); if (uvmexp.free < uvmexp.freemin) { module_thread_ticks = hz; } else if (mod->mod_autotime == 0) { continue; } else if (time_second < mod->mod_autotime) { module_thread_ticks = hz; continue; } else { mod->mod_autotime = 0; } /* * If this module wants to avoid autounload then * skip it. Some modules can ping-pong in and out * because their use is transient but often. * Example: exec_script. */ mi = mod->mod_info; error = (*mi->mi_modcmd)(MODULE_CMD_AUTOUNLOAD, NULL); if (error == 0 || error == ENOTTY) { (void)module_do_unload(mi->mi_name); } } mutex_exit(&module_lock); mutex_enter(&module_thread_lock); (void)cv_timedwait(&module_thread_cv, &module_thread_lock, module_thread_ticks); module_thread_ticks = 0; mutex_exit(&module_thread_lock); } } /* * module_thread: * * Kick the module thread into action, perhaps because the * system is low on memory. */ void module_thread_kick(void) { mutex_enter(&module_thread_lock); module_thread_ticks = hz; cv_broadcast(&module_thread_cv); mutex_exit(&module_thread_lock); } #ifdef DDB /* * module_whatis: * * Helper routine for DDB. */ void module_whatis(uintptr_t addr, void (*pr)(const char *, ...)) { module_t *mod; size_t msize; vaddr_t maddr; TAILQ_FOREACH(mod, &module_list, mod_chain) { kobj_stat(mod->mod_kobj, &maddr, &msize); if (addr < maddr || addr >= maddr + msize) { continue; } (*pr)("%p is %p+%zu, in kernel module `%s'\n", (void *)addr, (void *)maddr, (size_t)(addr - maddr), mod->mod_info->mi_name); } } /* * module_print_list: * * Helper routine for DDB. */ void module_print_list(void (*pr)(const char *, ...)) { const char *src; module_t *mod; size_t msize; vaddr_t maddr; (*pr)("%16s %16s %8s %8s\n", "NAME", "TEXT/DATA", "SIZE", "SOURCE"); TAILQ_FOREACH(mod, &module_list, mod_chain) { switch (mod->mod_source) { case MODULE_SOURCE_KERNEL: src = "builtin"; break; case MODULE_SOURCE_FILESYS: src = "filesys"; break; case MODULE_SOURCE_BOOT: src = "boot"; break; default: src = "unknown"; break; } kobj_stat(mod->mod_kobj, &maddr, &msize); (*pr)("%16s %16lx %8ld %8s\n", mod->mod_info->mi_name, (long)maddr, (long)msize, src); } } #endif /* DDB */