From c353c3fb0700a3c17ea2b0237710a184232ccd7f Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 2 Feb 2007 16:39:12 +0100 Subject: Driver core: let request_module() send a /sys/modules/kmod/-uevent On recent systems, calls to /sbin/modprobe are handled by udev depending on the kind of device the kernel has discovered. This patch creates an uevent for the kernels internal request_module(), to let udev take control over the request, instead of forking the binary directly by the kernel. The direct execution of /sbin/modprobe can be disabled by setting: /sys/module/kmod/mod_request_helper (/proc/sys/kernel/modprobe) to an empty string, the same way /proc/sys/kernel/hotplug is disabled on an udev system. Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- kernel/kmod.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) (limited to 'kernel/kmod.c') diff --git a/kernel/kmod.c b/kernel/kmod.c index 796276141e51..9f923f8ce6a0 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -36,6 +36,8 @@ #include #include +extern int delete_module(const char *name, unsigned int flags); + extern int max_threads; static struct workqueue_struct *khelper_wq; @@ -46,6 +48,7 @@ static struct workqueue_struct *khelper_wq; modprobe_path is set via /proc/sys. */ char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; +struct module_kobject kmod_mk; /** * request_module - try to load a kernel module @@ -75,6 +78,11 @@ int request_module(const char *fmt, ...) static atomic_t kmod_concurrent = ATOMIC_INIT(0); #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ static int kmod_loop_msg; + char modalias[16 + MODULE_NAME_LEN] = "MODALIAS="; + char *uevent_envp[2] = { + modalias, + NULL + }; va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); @@ -82,6 +90,12 @@ int request_module(const char *fmt, ...) if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; + strcpy(&modalias[strlen("MODALIAS=")], module_name); + kobject_uevent_env(&kmod_mk.kobj, KOBJ_CHANGE, uevent_envp); + + if (modprobe_path[0] == '\0') + goto out; + /* If modprobe needs a service that is in a module, we get a recursive * loop. Limit the number of running kmod threads to max_threads/2 or * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method @@ -108,9 +122,115 @@ int request_module(const char *fmt, ...) ret = call_usermodehelper(modprobe_path, argv, envp, 1); atomic_dec(&kmod_concurrent); +out: return ret; } EXPORT_SYMBOL(request_module); + +static ssize_t store_mod_request(struct module_attribute *mattr, + struct module *mod, + const char *buffer, size_t count) +{ + char name[MODULE_NAME_LEN]; + int ret; + + if (count < 1 || count+1 > MODULE_NAME_LEN) + return -EINVAL; + memcpy(name, buffer, count); + name[count] = '\0'; + if (name[count-1] == '\n') + name[count-1] = '\0'; + + ret = request_module(name); + if (ret < 0) + return ret; + return count; +} + +static struct module_attribute mod_request = { + .attr = { .name = "mod_request", .mode = S_IWUSR, .owner = THIS_MODULE }, + .store = store_mod_request, +}; + +#ifdef CONFIG_MODULE_UNLOAD +static ssize_t store_mod_unload(struct module_attribute *mattr, + struct module *mod, + const char *buffer, size_t count) +{ + char name[MODULE_NAME_LEN]; + int ret; + + if (count < 1 || count+1 > MODULE_NAME_LEN) + return -EINVAL; + memcpy(name, buffer, count); + name[count] = '\0'; + if (name[count-1] == '\n') + name[count-1] = '\0'; + + ret = delete_module(name, O_NONBLOCK); + if (ret < 0) + return ret; + return count; +} + +static struct module_attribute mod_unload = { + .attr = { .name = "mod_unload", .mode = S_IWUSR, .owner = THIS_MODULE }, + .store = store_mod_unload, +}; +#endif + +static ssize_t show_mod_request_helper(struct module_attribute *mattr, + struct module *mod, + char *buffer) +{ + return sprintf(buffer, "%s\n", modprobe_path); +} + +static ssize_t store_mod_request_helper(struct module_attribute *mattr, + struct module *mod, + const char *buffer, size_t count) +{ + if (count < 1 || count+1 > KMOD_PATH_LEN) + return -EINVAL; + memcpy(modprobe_path, buffer, count); + modprobe_path[count] = '\0'; + if (modprobe_path[count-1] == '\n') + modprobe_path[count-1] = '\0'; + return count; +} + +static struct module_attribute mod_request_helper = { + .attr = { + .name = "mod_request_helper", + .mode = S_IWUSR | S_IRUGO, + .owner = THIS_MODULE + }, + .show = show_mod_request_helper, + .store = store_mod_request_helper, +}; + +void __init kmod_sysfs_init(void) +{ + int ret; + + kmod_mk.mod = THIS_MODULE; + kobj_set_kset_s(&kmod_mk, module_subsys); + kobject_set_name(&kmod_mk.kobj, "kmod"); + kobject_init(&kmod_mk.kobj); + ret = kobject_add(&kmod_mk.kobj); + if (ret < 0) + goto out; + + ret = sysfs_create_file(&kmod_mk.kobj, &mod_request_helper.attr); + ret = sysfs_create_file(&kmod_mk.kobj, &mod_request.attr); +#ifdef CONFIG_MODULE_UNLOAD + ret = sysfs_create_file(&kmod_mk.kobj, &mod_unload.attr); +#endif + + kobject_uevent(&kmod_mk.kobj, KOBJ_ADD); +out: + return; +} #endif /* CONFIG_KMOD */ struct subprocess_info { -- cgit v1.2.3-59-g8ed1b