devtmpfs.c revision 5da4e689449ad99ab31cf2208d99eddfce0498ba
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> 24e454cea20bdcff10ee698d11b8882662a0153a47Kay Sievers#include <linux/sched.h> 255a0e3ad6af8660be21ca98a971cd00f331318c05Tejun Heo#include <linux/slab.h> 262780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro#include <linux/kthread.h> 272b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 282780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic struct task_struct *thread; 292b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#if defined CONFIG_DEVTMPFS_MOUNT 31fc14f2fef682df677d64a145256dbd263df2aa7bAl Virostatic int mount_dev = 1; 322b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#else 33fc14f2fef682df677d64a145256dbd263df2aa7bAl Virostatic int mount_dev; 342b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#endif 352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 362780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic DEFINE_SPINLOCK(req_lock); 372780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 382780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic struct req { 392780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro struct req *next; 402780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro struct completion done; 412780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro int err; 422780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro const char *name; 432780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro mode_t mode; /* 0 => delete */ 442780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro struct device *dev; 452780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro} *requests; 46ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers 472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int __init mount_param(char *str) 482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 49fc14f2fef682df677d64a145256dbd263df2aa7bAl Viro mount_dev = simple_strtoul(str, NULL, 0); 502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 1; 512b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers__setup("devtmpfs.mount=", mount_param); 532b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 54fc14f2fef682df677d64a145256dbd263df2aa7bAl Virostatic struct dentry *dev_mount(struct file_system_type *fs_type, int flags, 55fc14f2fef682df677d64a145256dbd263df2aa7bAl Viro const char *dev_name, void *data) 562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 57da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#ifdef CONFIG_TMPFS 58fc14f2fef682df677d64a145256dbd263df2aa7bAl Viro return mount_single(fs_type, flags, data, shmem_fill_super); 59da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#else 60fc14f2fef682df677d64a145256dbd263df2aa7bAl Viro return mount_single(fs_type, flags, data, ramfs_fill_super); 61da5e4ef7fdb8f2fb0878dee3bd9d4dd10cea8cf1Peter Korsgaard#endif 622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic struct file_system_type dev_fs_type = { 652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers .name = "devtmpfs", 66fc14f2fef682df677d64a145256dbd263df2aa7bAl Viro .mount = dev_mount, 672b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers .kill_sb = kill_litter_super, 682b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers}; 692b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#ifdef CONFIG_BLOCK 712b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic inline int is_blockdev(struct device *dev) 722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 732b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return dev->class == &block_class; 742b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 752b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#else 762b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic inline int is_blockdev(struct device *dev) { return 0; } 772b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers#endif 782b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 792780f1ff6aec0cf708a61c022d475bfcaa648965Al Viroint devtmpfs_create_node(struct device *dev) 802780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro{ 812780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro const char *tmp = NULL; 822780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro struct req req; 832780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 842780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (!thread) 852780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return 0; 862780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 872780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.mode = 0; 882780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.name = device_get_devnode(dev, &req.mode, &tmp); 892780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (!req.name) 902780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return -ENOMEM; 912780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 922780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (req.mode == 0) 932780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.mode = 0600; 942780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (is_blockdev(dev)) 952780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.mode |= S_IFBLK; 962780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro else 972780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.mode |= S_IFCHR; 982780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 992780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.dev = dev; 1002780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1012780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro init_completion(&req.done); 1022780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1032780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_lock(&req_lock); 1042780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.next = requests; 1052780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro requests = &req; 1062780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_unlock(&req_lock); 1072780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1082780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro wake_up_process(thread); 1092780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro wait_for_completion(&req.done); 1102780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1112780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro kfree(tmp); 1122780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1132780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return req.err; 1142780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro} 1152780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1162780f1ff6aec0cf708a61c022d475bfcaa648965Al Viroint devtmpfs_delete_node(struct device *dev) 1172780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro{ 1182780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro const char *tmp = NULL; 1192780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro struct req req; 1202780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1212780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (!thread) 1222780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return 0; 1232780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1242780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.name = device_get_devnode(dev, NULL, &tmp); 1252780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (!req.name) 1262780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return -ENOMEM; 1272780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1282780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.mode = 0; 1292780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.dev = dev; 1302780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1312780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro init_completion(&req.done); 1322780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1332780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_lock(&req_lock); 1342780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req.next = requests; 1352780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro requests = &req; 1362780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_unlock(&req_lock); 1372780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1382780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro wake_up_process(thread); 1392780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro wait_for_completion(&req.done); 1402780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1412780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro kfree(tmp); 1422780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return req.err; 1432780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro} 1442780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 1452b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_mkdir(const char *name, mode_t mode) 1462b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 1472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 14869753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro struct path path; 1492b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 1502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 15169753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dentry = kern_path_create(AT_FDCWD, name, &path, 1); 15269753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro if (IS_ERR(dentry)) 15369753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro return PTR_ERR(dentry); 15469753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro 15569753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro err = vfs_mkdir(path.dentry->d_inode, dentry, mode); 15669753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro if (!err) 15769753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro /* mark as kernel-created inode */ 15869753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dentry->d_inode->i_private = &thread; 15969753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dput(dentry); 16069753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro mutex_unlock(&path.dentry->d_inode->i_mutex); 16169753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro path_put(&path); 1622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 1632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 1642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int create_path(const char *nodepath) 1662b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 1675da4e689449ad99ab31cf2208d99eddfce0498baAl Viro char *path; 1685da4e689449ad99ab31cf2208d99eddfce0498baAl Viro char *s; 169015bf43b07158668c2f38af463939afcc6d19403Kay Sievers int err; 1702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1715da4e689449ad99ab31cf2208d99eddfce0498baAl Viro /* parent directories do not exist, create them */ 1725da4e689449ad99ab31cf2208d99eddfce0498baAl Viro path = kstrdup(nodepath, GFP_KERNEL); 1735da4e689449ad99ab31cf2208d99eddfce0498baAl Viro if (!path) 1745da4e689449ad99ab31cf2208d99eddfce0498baAl Viro return -ENOMEM; 1755da4e689449ad99ab31cf2208d99eddfce0498baAl Viro 1765da4e689449ad99ab31cf2208d99eddfce0498baAl Viro s = path; 1775da4e689449ad99ab31cf2208d99eddfce0498baAl Viro for (;;) { 1785da4e689449ad99ab31cf2208d99eddfce0498baAl Viro s = strchr(s, '/'); 1795da4e689449ad99ab31cf2208d99eddfce0498baAl Viro if (!s) 1805da4e689449ad99ab31cf2208d99eddfce0498baAl Viro break; 1815da4e689449ad99ab31cf2208d99eddfce0498baAl Viro s[0] = '\0'; 1825da4e689449ad99ab31cf2208d99eddfce0498baAl Viro err = dev_mkdir(path, 0755); 1835da4e689449ad99ab31cf2208d99eddfce0498baAl Viro if (err && err != -EEXIST) 1845da4e689449ad99ab31cf2208d99eddfce0498baAl Viro break; 1855da4e689449ad99ab31cf2208d99eddfce0498baAl Viro s[0] = '/'; 1865da4e689449ad99ab31cf2208d99eddfce0498baAl Viro s++; 1872b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 1885da4e689449ad99ab31cf2208d99eddfce0498baAl Viro kfree(path); 1892b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 1902b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 1912b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 1922780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic int handle_create(const char *nodename, mode_t mode, struct device *dev) 1932b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 1942b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 19569753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro struct path path; 1962b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 1972b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 19869753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dentry = kern_path_create(AT_FDCWD, nodename, &path, 0); 19969753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro if (dentry == ERR_PTR(-ENOENT)) { 2002b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers create_path(nodename); 20169753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dentry = kern_path_create(AT_FDCWD, nodename, &path, 0); 2022b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 20369753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro if (IS_ERR(dentry)) 20469753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro return PTR_ERR(dentry); 20569753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro 20669753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro err = vfs_mknod(path.dentry->d_inode, 20769753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dentry, mode, dev->devt); 20869753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro if (!err) { 20969753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro struct iattr newattrs; 21069753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro 21169753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro /* fixup possibly umasked mode */ 21269753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro newattrs.ia_mode = mode; 21369753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro newattrs.ia_valid = ATTR_MODE; 21469753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro mutex_lock(&dentry->d_inode->i_mutex); 21569753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro notify_change(dentry, &newattrs); 21669753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro mutex_unlock(&dentry->d_inode->i_mutex); 21769753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro 21869753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro /* mark as kernel-created inode */ 21969753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dentry->d_inode->i_private = &thread; 2202b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 22169753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro dput(dentry); 2222b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 22369753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro mutex_unlock(&path.dentry->d_inode->i_mutex); 22469753a0f14d3cb2e8a70e559ef8d409e4deeac8aAl Viro path_put(&path); 2252b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2262b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 2272b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2282b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_rmdir(const char *name) 2292b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct nameidata nd; 2312b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 2322b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 2332b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2342780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro err = kern_path_parent(name, &nd); 2352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 2362b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2372b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2382b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 2392b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len); 2402b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!IS_ERR(dentry)) { 241015bf43b07158668c2f38af463939afcc6d19403Kay Sievers if (dentry->d_inode) { 2422780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (dentry->d_inode->i_private == &thread) 243015bf43b07158668c2f38af463939afcc6d19403Kay Sievers err = vfs_rmdir(nd.path.dentry->d_inode, 244015bf43b07158668c2f38af463939afcc6d19403Kay Sievers dentry); 245015bf43b07158668c2f38af463939afcc6d19403Kay Sievers else 246015bf43b07158668c2f38af463939afcc6d19403Kay Sievers err = -EPERM; 247015bf43b07158668c2f38af463939afcc6d19403Kay Sievers } else { 2482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = -ENOENT; 249015bf43b07158668c2f38af463939afcc6d19403Kay Sievers } 2502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dput(dentry); 2512b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 2522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(dentry); 2532b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 2542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 255015bf43b07158668c2f38af463939afcc6d19403Kay Sievers mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 2562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path_put(&nd.path); 2572b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2582b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 2592b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2602b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int delete_path(const char *nodepath) 2612b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers const char *path; 2632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err = 0; 2642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2652b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path = kstrdup(nodepath, GFP_KERNEL); 2662b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!path) 2672b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return -ENOMEM; 2682b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 269ed413ae6e7813d3227eef43bc6d84ca4f4fe6b21Kay Sievers for (;;) { 2702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers char *base; 2712b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers base = strrchr(path, '/'); 2732b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!base) 2742b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers break; 2752b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers base[0] = '\0'; 2762b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = dev_rmdir(path); 2772b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 2782b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers break; 2792b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 2802b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2812b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers kfree(path); 2822b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 2832b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 2842b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2852b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversstatic int dev_mynode(struct device *dev, struct inode *inode, struct kstat *stat) 2862b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 2872b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* did we create it */ 2882780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (inode->i_private != &thread) 2892b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2902b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 2912b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* does the dev_t match */ 2922b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (is_blockdev(dev)) { 2932b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!S_ISBLK(stat->mode)) 2942b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2952b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 2962b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!S_ISCHR(stat->mode)) 2972b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 2982b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 2992b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (stat->rdev != dev->devt) 3002b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 3012b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3022b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers /* ours */ 3032b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 1; 3042b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 3052b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3062780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic int handle_remove(const char *nodename, struct device *dev) 3072b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 3082b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct nameidata nd; 3092b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct dentry *dentry; 3102b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers struct kstat stat; 3112b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int deleted = 1; 3122b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 3132b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3142780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro err = kern_path_parent(nodename, &nd); 3152b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 3162780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return err; 3172b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3182b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 3192b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len); 3202b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!IS_ERR(dentry)) { 3212b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (dentry->d_inode) { 3222b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_getattr(nd.path.mnt, dentry, &stat); 3232b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!err && dev_mynode(dev, dentry->d_inode, &stat)) { 3245e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers struct iattr newattrs; 3255e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers /* 3265e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers * before unlinking this node, reset permissions 3275e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers * of possible references like hardlinks 3285e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers */ 3295e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_uid = 0; 3305e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_gid = 0; 3315e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_mode = stat.mode & ~0777; 3325e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers newattrs.ia_valid = 3335e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers ATTR_UID|ATTR_GID|ATTR_MODE; 3345e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers mutex_lock(&dentry->d_inode->i_mutex); 3355e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers notify_change(dentry, &newattrs); 3365e31d76f2817bd50258a092a7c5b15b3006fd61cKay Sievers mutex_unlock(&dentry->d_inode->i_mutex); 3372b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = vfs_unlink(nd.path.dentry->d_inode, 3382b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dentry); 3392b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (!err || err == -ENOENT) 3402b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers deleted = 1; 3412b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3422b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 3432b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = -ENOENT; 3442b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3452b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers dput(dentry); 3462b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } else { 3472b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers err = PTR_ERR(dentry); 3482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 3492b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 3502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3512b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers path_put(&nd.path); 3522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (deleted && strchr(nodename, '/')) 3532b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers delete_path(nodename); 3542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 3552b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 3562b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3572b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers/* 3582b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * If configured, or requested by the commandline, devtmpfs will be 3592b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * auto-mounted after the kernel mounted the root filesystem. 3602b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers */ 361073120cc28ad9f6003452c8bb9d15a87b1820201Kay Sieversint devtmpfs_mount(const char *mntdir) 3622b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 3632b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers int err; 3642b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 365fc14f2fef682df677d64a145256dbd263df2aa7bAl Viro if (!mount_dev) 3662b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 3672b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3682780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (!thread) 3692b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 3702b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 371073120cc28ad9f6003452c8bb9d15a87b1820201Kay Sievers err = sys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT, NULL); 3722b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) 3732b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_INFO "devtmpfs: error mounting %i\n", err); 3742b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers else 3752b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_INFO "devtmpfs: mounted\n"); 3762b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 3772b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 3782b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 3792780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic __initdata DECLARE_COMPLETION(setup_done); 3802780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 3812780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic int handle(const char *name, mode_t mode, struct device *dev) 3822780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro{ 3832780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (mode) 3842780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return handle_create(name, mode, dev); 3852780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro else 3862780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return handle_remove(name, dev); 3872780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro} 3882780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 3892780f1ff6aec0cf708a61c022d475bfcaa648965Al Virostatic int devtmpfsd(void *p) 3902780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro{ 3912780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro char options[] = "mode=0755"; 3922780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro int *err = p; 3932780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro *err = sys_unshare(CLONE_NEWNS); 3942780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (*err) 3952780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro goto out; 3962780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro *err = sys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options); 3972780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (*err) 3982780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro goto out; 3992780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro sys_chdir("/.."); /* will traverse into overmounted root */ 4002780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro sys_chroot("."); 4012780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro complete(&setup_done); 4022780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro while (1) { 4032780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_lock(&req_lock); 4042780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro while (requests) { 4052780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro struct req *req = requests; 4062780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro requests = NULL; 4072780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_unlock(&req_lock); 4082780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro while (req) { 4092780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req->err = handle(req->name, req->mode, req->dev); 4102780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro complete(&req->done); 4112780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro req = req->next; 4122780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro } 4132780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_lock(&req_lock); 4142780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro } 4152780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro set_current_state(TASK_INTERRUPTIBLE); 4162780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro spin_unlock(&req_lock); 4172780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro schedule(); 4182780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro __set_current_state(TASK_RUNNING); 4192780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro } 4202780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return 0; 4212780f1ff6aec0cf708a61c022d475bfcaa648965Al Viroout: 4222780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro complete(&setup_done); 4232780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro return *err; 4242780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro} 4252780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 4262b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers/* 4272b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * Create devtmpfs instance, driver-core devices will add their device 4282b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers * nodes here. 4292b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers */ 4302b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sieversint __init devtmpfs_init(void) 4312b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers{ 4322780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro int err = register_filesystem(&dev_fs_type); 4332b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers if (err) { 4342b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_ERR "devtmpfs: unable to register devtmpfs " 4352b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers "type %i\n", err); 4362b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 4372b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 4382b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 4392780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro thread = kthread_run(devtmpfsd, &err, "kdevtmpfs"); 4402780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (!IS_ERR(thread)) { 4412780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro wait_for_completion(&setup_done); 4422780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro } else { 4432780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro err = PTR_ERR(thread); 4442780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro thread = NULL; 4452780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro } 4462780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro 4472780f1ff6aec0cf708a61c022d475bfcaa648965Al Viro if (err) { 4482b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err); 4492b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers unregister_filesystem(&dev_fs_type); 4502b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return err; 4512b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers } 4522b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers 4532b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers printk(KERN_INFO "devtmpfs: initialized\n"); 4542b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers return 0; 4552b2af54a5bb6f7e80ccf78f20084b93c398c3a8bKay Sievers} 456