devtmpfs.c revision da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1
12b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers/* 22b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * devtmpfs - kernel-maintained tmpfs-based /dev 32b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * 42b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * Copyright (C) 2009, Kay Sievers <kay.sievers@vrfy.org> 52b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * 62b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * During bootup, before any driver core device is registered, 72b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * devtmpfs, a tmpfs-based filesystem is created. Every driver-core 82b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * device which requests a device node, will add a node in this 9e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers * filesystem. 10e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers * By default, all devices are named after the the name of the 11e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers * device, owned by root and have a default mode of 0600. Subsystems 12e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers * can overwrite the default setting if needed. 132b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers */ 142b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 152b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/kernel.h> 162b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/syscalls.h> 172b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/mount.h> 182b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/device.h> 192b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/genhd.h> 202b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/namei.h> 212b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/fs.h> 222b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/shmem_fs.h> 23da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#include <linux/ramfs.h> 242b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/cred.h> 25e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers#include <linux/sched.h> 262b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#include <linux/init_task.h> 275a0e3ad6af8660be21ca98a971cd00f331318c05Tejun Heo#include <linux/slab.h> 282b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 292b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic struct vfsmount *dev_mnt; 302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 312b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#if defined CONFIG_DEVTMPFS_MOUNT 322b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_mount = 1; 332b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#else 342b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_mount; 352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#endif 362b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 37f1f76f865b5f66db5b5c7f2d19874f2bb9b43b8dThomas Gleixnerstatic DEFINE_MUTEX(dirlock); 38ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers 392b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int __init mount_param(char *str) 402b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 412b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dev_mount = simple_strtoul(str, NULL, 0); 422b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 1; 432b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 442b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers__setup("devtmpfs.mount=", mount_param); 452b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 462b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_get_sb(struct file_system_type *fs_type, int flags, 472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *dev_name, void *data, struct vfsmount *mnt) 482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 49da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#ifdef CONFIG_TMPFS 502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return get_sb_single(fs_type, flags, data, shmem_fill_super, mnt); 51da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#else 52da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard return get_sb_single(fs_type, flags, data, ramfs_fill_super, mnt); 53da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#endif 542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 552b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic struct file_system_type dev_fs_type = { 572b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers .name = "devtmpfs", 582b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers .get_sb = dev_get_sb, 592b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers .kill_sb = kill_litter_super, 602b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers}; 612b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#ifdef CONFIG_BLOCK 632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic inline int is_blockdev(struct device *dev) 642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return dev->class == &block_class; 662b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 672b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#else 682b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic inline int is_blockdev(struct device *dev) { return 0; } 692b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#endif 702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 712b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_mkdir(const char *name, mode_t mode) 722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 732b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct nameidata nd; 742b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 752b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 762b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 772b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt, 782b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers name, LOOKUP_PARENT, &nd); 792b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 802b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 812b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 822b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry = lookup_create(&nd, 1); 832b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!IS_ERR(dentry)) { 842b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); 85015bf43b07158668c2f38af463939afcc6d19403Kay Sievers if (!err) 86015bf43b07158668c2f38af463939afcc6d19403Kay Sievers /* mark as kernel-created inode */ 87015bf43b07158668c2f38af463939afcc6d19403Kay Sievers dentry->d_inode->i_private = &dev_mnt; 882b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dput(dentry); 892b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 902b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(dentry); 912b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 922b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 93015bf43b07158668c2f38af463939afcc6d19403Kay Sievers mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 942b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path_put(&nd.path); 952b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 962b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 972b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 982b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int create_path(const char *nodepath) 992b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 100015bf43b07158668c2f38af463939afcc6d19403Kay Sievers int err; 1012b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 102f1f76f865b5f66db5b5c7f2d19874f2bb9b43b8dThomas Gleixner mutex_lock(&dirlock); 103015bf43b07158668c2f38af463939afcc6d19403Kay Sievers err = dev_mkdir(nodepath, 0755); 104015bf43b07158668c2f38af463939afcc6d19403Kay Sievers if (err == -ENOENT) { 105ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers char *path; 1062b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers char *s; 1072b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1082b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* parent directories do not exist, create them */ 109ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers path = kstrdup(nodepath, GFP_KERNEL); 1108042273801059884da2d53bbca34575d090b6f4eKay Sievers if (!path) { 1118042273801059884da2d53bbca34575d090b6f4eKay Sievers err = -ENOMEM; 1128042273801059884da2d53bbca34575d090b6f4eKay Sievers goto out; 1138042273801059884da2d53bbca34575d090b6f4eKay Sievers } 1142b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers s = path; 115ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers for (;;) { 1162b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers s = strchr(s, '/'); 1172b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!s) 1182b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers break; 1192b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers s[0] = '\0'; 1202b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = dev_mkdir(path, 0755); 1212b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err && err != -EEXIST) 1222b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers break; 1232b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers s[0] = '/'; 1242b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers s++; 1252b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 126ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers kfree(path); 1272b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 1288042273801059884da2d53bbca34575d090b6f4eKay Sieversout: 129f1f76f865b5f66db5b5c7f2d19874f2bb9b43b8dThomas Gleixner mutex_unlock(&dirlock); 1302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 1312b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 1322b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1332b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversint devtmpfs_create_node(struct device *dev) 1342b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 1352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *tmp = NULL; 1362b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *nodename; 1372b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const struct cred *curr_cred; 138e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers mode_t mode = 0; 1392b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct nameidata nd; 1402b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 1412b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 1422b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1432b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!dev_mnt) 1442b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 1452b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 146e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers nodename = device_get_devnode(dev, &mode, &tmp); 1472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!nodename) 1482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return -ENOMEM; 1492b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 150e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers if (mode == 0) 151e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers mode = 0600; 1522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (is_blockdev(dev)) 153e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers mode |= S_IFBLK; 1542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers else 155e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers mode |= S_IFCHR; 1562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1572b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers curr_cred = override_creds(&init_cred); 1580092699643703aefca6af0aa758a73f1624d53beKay Sievers 1592b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt, 1602b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers nodename, LOOKUP_PARENT, &nd); 1612b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err == -ENOENT) { 1622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers create_path(nodename); 1632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt, 1642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers nodename, LOOKUP_PARENT, &nd); 1652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 1660092699643703aefca6af0aa758a73f1624d53beKay Sievers if (err) 1670092699643703aefca6af0aa758a73f1624d53beKay Sievers goto out; 1682b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1692b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry = lookup_create(&nd, 0); 1702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!IS_ERR(dentry)) { 1712b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_mknod(nd.path.dentry->d_inode, 1722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry, mode, dev->devt); 1730092699643703aefca6af0aa758a73f1624d53beKay Sievers if (!err) { 1740092699643703aefca6af0aa758a73f1624d53beKay Sievers struct iattr newattrs; 1750092699643703aefca6af0aa758a73f1624d53beKay Sievers 1760092699643703aefca6af0aa758a73f1624d53beKay Sievers /* fixup possibly umasked mode */ 1770092699643703aefca6af0aa758a73f1624d53beKay Sievers newattrs.ia_mode = mode; 1780092699643703aefca6af0aa758a73f1624d53beKay Sievers newattrs.ia_valid = ATTR_MODE; 1790092699643703aefca6af0aa758a73f1624d53beKay Sievers mutex_lock(&dentry->d_inode->i_mutex); 1800092699643703aefca6af0aa758a73f1624d53beKay Sievers notify_change(dentry, &newattrs); 1810092699643703aefca6af0aa758a73f1624d53beKay Sievers mutex_unlock(&dentry->d_inode->i_mutex); 1820092699643703aefca6af0aa758a73f1624d53beKay Sievers 1830092699643703aefca6af0aa758a73f1624d53beKay Sievers /* mark as kernel-created inode */ 1842b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry->d_inode->i_private = &dev_mnt; 1850092699643703aefca6af0aa758a73f1624d53beKay Sievers } 1862b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dput(dentry); 1872b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 1882b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(dentry); 1892b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 1902b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1910092699643703aefca6af0aa758a73f1624d53beKay Sievers mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 1922b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path_put(&nd.path); 1932b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversout: 1942b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers kfree(tmp); 1952b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers revert_creds(curr_cred); 1962b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 1972b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 1982b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1992b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_rmdir(const char *name) 2002b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2012b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct nameidata nd; 2022b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 2032b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 2042b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2052b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt, 2062b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers name, LOOKUP_PARENT, &nd); 2072b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 2082b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2092b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2102b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 2112b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len); 2122b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!IS_ERR(dentry)) { 213015bf43b07158668c2f38af463939afcc6d19403Kay Sievers if (dentry->d_inode) { 214015bf43b07158668c2f38af463939afcc6d19403Kay Sievers if (dentry->d_inode->i_private == &dev_mnt) 215015bf43b07158668c2f38af463939afcc6d19403Kay Sievers err = vfs_rmdir(nd.path.dentry->d_inode, 216015bf43b07158668c2f38af463939afcc6d19403Kay Sievers dentry); 217015bf43b07158668c2f38af463939afcc6d19403Kay Sievers else 218015bf43b07158668c2f38af463939afcc6d19403Kay Sievers err = -EPERM; 219015bf43b07158668c2f38af463939afcc6d19403Kay Sievers } else { 2202b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = -ENOENT; 221015bf43b07158668c2f38af463939afcc6d19403Kay Sievers } 2222b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dput(dentry); 2232b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 2242b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(dentry); 2252b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 2262b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 227015bf43b07158668c2f38af463939afcc6d19403Kay Sievers mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 2282b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path_put(&nd.path); 2292b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 2312b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2322b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int delete_path(const char *nodepath) 2332b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2342b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *path; 2352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err = 0; 2362b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2372b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path = kstrdup(nodepath, GFP_KERNEL); 2382b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!path) 2392b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return -ENOMEM; 2402b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 241f1f76f865b5f66db5b5c7f2d19874f2bb9b43b8dThomas Gleixner mutex_lock(&dirlock); 242ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers for (;;) { 2432b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers char *base; 2442b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2452b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers base = strrchr(path, '/'); 2462b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!base) 2472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers break; 2482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers base[0] = '\0'; 2492b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = dev_rmdir(path); 2502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 2512b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers break; 2522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 253f1f76f865b5f66db5b5c7f2d19874f2bb9b43b8dThomas Gleixner mutex_unlock(&dirlock); 2542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2552b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers kfree(path); 2562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2572b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 2582b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2592b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_mynode(struct device *dev, struct inode *inode, struct kstat *stat) 2602b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2612b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* did we create it */ 2622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (inode->i_private != &dev_mnt) 2632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* does the dev_t match */ 2662b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (is_blockdev(dev)) { 2672b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!S_ISBLK(stat->mode)) 2682b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2692b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 2702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!S_ISCHR(stat->mode)) 2712b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 2732b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (stat->rdev != dev->devt) 2742b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2752b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2762b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* ours */ 2772b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 1; 2782b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 2792b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2802b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversint devtmpfs_delete_node(struct device *dev) 2812b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2822b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *tmp = NULL; 2832b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *nodename; 2842b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const struct cred *curr_cred; 2852b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct nameidata nd; 2862b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 2872b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct kstat stat; 2882b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int deleted = 1; 2892b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 2902b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2912b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!dev_mnt) 2922b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2932b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 294e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers nodename = device_get_devnode(dev, NULL, &tmp); 2952b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!nodename) 2962b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return -ENOMEM; 2972b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2982b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers curr_cred = override_creds(&init_cred); 2992b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt, 3002b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers nodename, LOOKUP_PARENT, &nd); 3012b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 3022b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers goto out; 3032b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3042b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 3052b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len); 3062b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!IS_ERR(dentry)) { 3072b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (dentry->d_inode) { 3082b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_getattr(nd.path.mnt, dentry, &stat); 3092b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!err && dev_mynode(dev, dentry->d_inode, &stat)) { 3105e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers struct iattr newattrs; 3115e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers /* 3125e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers * before unlinking this node, reset permissions 3135e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers * of possible references like hardlinks 3145e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers */ 3155e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_uid = 0; 3165e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_gid = 0; 3175e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_mode = stat.mode & ~0777; 3185e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_valid = 3195e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers ATTR_UID|ATTR_GID|ATTR_MODE; 3205e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers mutex_lock(&dentry->d_inode->i_mutex); 3215e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers notify_change(dentry, &newattrs); 3225e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers mutex_unlock(&dentry->d_inode->i_mutex); 3232b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_unlink(nd.path.dentry->d_inode, 3242b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry); 3252b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!err || err == -ENOENT) 3262b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers deleted = 1; 3272b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3282b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 3292b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = -ENOENT; 3302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3312b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dput(dentry); 3322b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 3332b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(dentry); 3342b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 3362b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3372b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path_put(&nd.path); 3382b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (deleted && strchr(nodename, '/')) 3392b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers delete_path(nodename); 3402b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversout: 3412b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers kfree(tmp); 3422b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers revert_creds(curr_cred); 3432b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 3442b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 3452b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3462b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers/* 3472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * If configured, or requested by the commandline, devtmpfs will be 3482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * auto-mounted after the kernel mounted the root filesystem. 3492b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers */ 350073120cc28ad9f6003452c8bb9d15a87b1820201Kay Sieversint devtmpfs_mount(const char *mntdir) 3512b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 3522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 3532b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!dev_mount) 3552b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 3562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3572b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!dev_mnt) 3582b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 3592b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 360073120cc28ad9f6003452c8bb9d15a87b1820201Kay Sievers err = sys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT, NULL); 3612b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 3622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_INFO "devtmpfs: error mounting %i\n", err); 3632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers else 3642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_INFO "devtmpfs: mounted\n"); 3652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 3662b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 3672b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3682b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers/* 3692b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * Create devtmpfs instance, driver-core devices will add their device 3702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * nodes here. 3712b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers */ 3722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversint __init devtmpfs_init(void) 3732b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 3742b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 3752b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct vfsmount *mnt; 376f776c5ec4690b21b3668ad5956774a22c86f541aHeiko Carstens char options[] = "mode=0755"; 3772b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3782b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = register_filesystem(&dev_fs_type); 3792b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) { 3802b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_ERR "devtmpfs: unable to register devtmpfs " 3812b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers "type %i\n", err); 3822b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 3832b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3842b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 385f776c5ec4690b21b3668ad5956774a22c86f541aHeiko Carstens mnt = kern_mount_data(&dev_fs_type, options); 3862b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (IS_ERR(mnt)) { 3872b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(mnt); 3882b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err); 3892b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers unregister_filesystem(&dev_fs_type); 3902b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 3912b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3922b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dev_mnt = mnt; 3932b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3942b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_INFO "devtmpfs: initialized\n"); 3952b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 3962b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 397