177b14db5SEric W. Biederman /* 277b14db5SEric W. Biederman * /proc/sys support 377b14db5SEric W. Biederman */ 41e0edd3fSAlexey Dobriyan #include <linux/init.h> 577b14db5SEric W. Biederman #include <linux/sysctl.h> 6f1ecf068SLucas De Marchi #include <linux/poll.h> 777b14db5SEric W. Biederman #include <linux/proc_fs.h> 887ebdc00SAndrew Morton #include <linux/printk.h> 977b14db5SEric W. Biederman #include <linux/security.h> 1040401530SAl Viro #include <linux/sched.h> 115b825c3aSIngo Molnar #include <linux/cred.h> 1234286d66SNick Piggin #include <linux/namei.h> 1340401530SAl Viro #include <linux/mm.h> 141f87f0b5SEric W. Biederman #include <linux/module.h> 1577b14db5SEric W. Biederman #include "internal.h" 1677b14db5SEric W. Biederman 17d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1877b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 1903a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 209043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 219043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 2277b14db5SEric W. Biederman 23f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 24f9bd6733SEric W. Biederman 25f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 26f9bd6733SEric W. Biederman { } 27f9bd6733SEric W. Biederman }; 28f9bd6733SEric W. Biederman 29f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 30f9bd6733SEric W. Biederman { 31f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 32f9bd6733SEric W. Biederman } 33f9bd6733SEric W. Biederman 34f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 35f9bd6733SEric W. Biederman { 36f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 37f9bd6733SEric W. Biederman } 38f9bd6733SEric W. Biederman 39f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 40f9bd6733SEric W. Biederman 41f9bd6733SEric W. Biederman { 42f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 43f9bd6733SEric W. Biederman } 44f9bd6733SEric W. Biederman 45f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 46f1ecf068SLucas De Marchi { 47f1ecf068SLucas De Marchi if (!poll) 48f1ecf068SLucas De Marchi return; 49f1ecf068SLucas De Marchi 50f1ecf068SLucas De Marchi atomic_inc(&poll->event); 51f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 52f1ecf068SLucas De Marchi } 53f1ecf068SLucas De Marchi 54a194558eSEric W. Biederman static struct ctl_table root_table[] = { 55a194558eSEric W. Biederman { 56a194558eSEric W. Biederman .procname = "", 577ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 58a194558eSEric W. Biederman }, 59a194558eSEric W. Biederman { } 60a194558eSEric W. Biederman }; 610e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 620e47c99dSEric W. Biederman .default_set.dir.header = { 631f87f0b5SEric W. Biederman {{.count = 1, 64938aaa4fSEric W. Biederman .nreg = 1, 65ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 660e47c99dSEric W. Biederman .ctl_table_arg = root_table, 671f87f0b5SEric W. Biederman .root = &sysctl_table_root, 681f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 697ec66d06SEric W. Biederman }, 701f87f0b5SEric W. Biederman }; 711f87f0b5SEric W. Biederman 721f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 731f87f0b5SEric W. Biederman 747ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 750e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 7613bcc6a2SEric W. Biederman struct ctl_table **pentry); 770e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 780e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 797ec66d06SEric W. Biederman 806980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 816980128fSEric W. Biederman { 826980128fSEric W. Biederman if (dir->header.parent) 836980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 8487ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 856980128fSEric W. Biederman } 866980128fSEric W. Biederman 87076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 88076c3eedSEric W. Biederman { 89076c3eedSEric W. Biederman int minlen; 90076c3eedSEric W. Biederman int cmp; 91076c3eedSEric W. Biederman 92076c3eedSEric W. Biederman minlen = len1; 93076c3eedSEric W. Biederman if (minlen > len2) 94076c3eedSEric W. Biederman minlen = len2; 95076c3eedSEric W. Biederman 96076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 97076c3eedSEric W. Biederman if (cmp == 0) 98076c3eedSEric W. Biederman cmp = len1 - len2; 99076c3eedSEric W. Biederman return cmp; 100076c3eedSEric W. Biederman } 101076c3eedSEric W. Biederman 10260f126d9SEric W. Biederman /* Called under sysctl_lock */ 103076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1040e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 105076c3eedSEric W. Biederman { 106076c3eedSEric W. Biederman struct ctl_table_header *head; 107076c3eedSEric W. Biederman struct ctl_table *entry; 108ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 109076c3eedSEric W. Biederman 110ac13ac6fSEric W. Biederman while (node) 111ac13ac6fSEric W. Biederman { 112ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 113ac13ac6fSEric W. Biederman const char *procname; 114ac13ac6fSEric W. Biederman int cmp; 115ac13ac6fSEric W. Biederman 116ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 117ac13ac6fSEric W. Biederman head = ctl_node->header; 118ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 119ac13ac6fSEric W. Biederman procname = entry->procname; 120ac13ac6fSEric W. Biederman 121ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 122ac13ac6fSEric W. Biederman if (cmp < 0) 123ac13ac6fSEric W. Biederman node = node->rb_left; 124ac13ac6fSEric W. Biederman else if (cmp > 0) 125ac13ac6fSEric W. Biederman node = node->rb_right; 126ac13ac6fSEric W. Biederman else { 127076c3eedSEric W. Biederman *phead = head; 128076c3eedSEric W. Biederman return entry; 129076c3eedSEric W. Biederman } 130076c3eedSEric W. Biederman } 131076c3eedSEric W. Biederman return NULL; 132076c3eedSEric W. Biederman } 133076c3eedSEric W. Biederman 134ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 135ac13ac6fSEric W. Biederman { 136ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 137ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 138ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 139ac13ac6fSEric W. Biederman const char *name = entry->procname; 140ac13ac6fSEric W. Biederman int namelen = strlen(name); 141ac13ac6fSEric W. Biederman 142ac13ac6fSEric W. Biederman while (*p) { 143ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 144ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 145ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 146ac13ac6fSEric W. Biederman const char *parent_name; 147ac13ac6fSEric W. Biederman int cmp; 148ac13ac6fSEric W. Biederman 149ac13ac6fSEric W. Biederman parent = *p; 150ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 151ac13ac6fSEric W. Biederman parent_head = parent_node->header; 152ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 153ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 154ac13ac6fSEric W. Biederman 155ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 156ac13ac6fSEric W. Biederman if (cmp < 0) 157ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 158ac13ac6fSEric W. Biederman else if (cmp > 0) 159ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 160ac13ac6fSEric W. Biederman else { 16187ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 162ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 16387ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 164ac13ac6fSEric W. Biederman return -EEXIST; 165ac13ac6fSEric W. Biederman } 166ac13ac6fSEric W. Biederman } 167ac13ac6fSEric W. Biederman 168ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 169ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 170ac13ac6fSEric W. Biederman return 0; 171ac13ac6fSEric W. Biederman } 172ac13ac6fSEric W. Biederman 173ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 174ac13ac6fSEric W. Biederman { 175ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 176ac13ac6fSEric W. Biederman 177ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 178ac13ac6fSEric W. Biederman } 179ac13ac6fSEric W. Biederman 180e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 181e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 182ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 183e0d04529SEric W. Biederman { 1847ec66d06SEric W. Biederman head->ctl_table = table; 185e0d04529SEric W. Biederman head->ctl_table_arg = table; 186e0d04529SEric W. Biederman head->used = 0; 187e0d04529SEric W. Biederman head->count = 1; 188e0d04529SEric W. Biederman head->nreg = 1; 189e0d04529SEric W. Biederman head->unregistering = NULL; 190e0d04529SEric W. Biederman head->root = root; 191e0d04529SEric W. Biederman head->set = set; 192e0d04529SEric W. Biederman head->parent = NULL; 193ac13ac6fSEric W. Biederman head->node = node; 1942fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 195ac13ac6fSEric W. Biederman if (node) { 196ac13ac6fSEric W. Biederman struct ctl_table *entry; 1974c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 198ac13ac6fSEric W. Biederman node->header = head; 199ac13ac6fSEric W. Biederman } 200ac13ac6fSEric W. Biederman } 201e0d04529SEric W. Biederman 2028425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2038425d6aaSEric W. Biederman { 204ac13ac6fSEric W. Biederman struct ctl_table *entry; 205ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 206ac13ac6fSEric W. Biederman erase_entry(head, entry); 2078425d6aaSEric W. Biederman } 2088425d6aaSEric W. Biederman 2090e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2108425d6aaSEric W. Biederman { 211ac13ac6fSEric W. Biederman struct ctl_table *entry; 2120e47c99dSEric W. Biederman int err; 2130e47c99dSEric W. Biederman 214f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 215f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 216f9bd6733SEric W. Biederman return -EROFS; 217f9bd6733SEric W. Biederman 218f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 219f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 220f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 221f9bd6733SEric W. Biederman return -EINVAL; 222f9bd6733SEric W. Biederman set_empty_dir(dir); 223f9bd6733SEric W. Biederman } 224f9bd6733SEric W. Biederman 2250e47c99dSEric W. Biederman dir->header.nreg++; 2267ec66d06SEric W. Biederman header->parent = dir; 2270e47c99dSEric W. Biederman err = insert_links(header); 2280e47c99dSEric W. Biederman if (err) 2290e47c99dSEric W. Biederman goto fail_links; 230ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 231ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 232ac13ac6fSEric W. Biederman if (err) 233ac13ac6fSEric W. Biederman goto fail; 234ac13ac6fSEric W. Biederman } 2350e47c99dSEric W. Biederman return 0; 236ac13ac6fSEric W. Biederman fail: 237ac13ac6fSEric W. Biederman erase_header(header); 238ac13ac6fSEric W. Biederman put_links(header); 2390e47c99dSEric W. Biederman fail_links: 240f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 241f9bd6733SEric W. Biederman clear_empty_dir(dir); 2420e47c99dSEric W. Biederman header->parent = NULL; 2430e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2440e47c99dSEric W. Biederman return err; 2458425d6aaSEric W. Biederman } 2468425d6aaSEric W. Biederman 2471f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2481f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2491f87f0b5SEric W. Biederman { 2501f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2511f87f0b5SEric W. Biederman return 0; 2521f87f0b5SEric W. Biederman p->used++; 2531f87f0b5SEric W. Biederman return 1; 2541f87f0b5SEric W. Biederman } 2551f87f0b5SEric W. Biederman 2561f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2571f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2581f87f0b5SEric W. Biederman { 2591f87f0b5SEric W. Biederman if (!--p->used) 2601f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2611f87f0b5SEric W. Biederman complete(p->unregistering); 2621f87f0b5SEric W. Biederman } 2631f87f0b5SEric W. Biederman 264d6cffbbeSKonstantin Khlebnikov static void proc_sys_prune_dcache(struct ctl_table_header *head) 265d6cffbbeSKonstantin Khlebnikov { 2662fd1d2c4SEric W. Biederman struct inode *inode; 267d6cffbbeSKonstantin Khlebnikov struct proc_inode *ei; 2682fd1d2c4SEric W. Biederman struct hlist_node *node; 2692fd1d2c4SEric W. Biederman struct super_block *sb; 270d6cffbbeSKonstantin Khlebnikov 271ace0c791SEric W. Biederman rcu_read_lock(); 2722fd1d2c4SEric W. Biederman for (;;) { 2732fd1d2c4SEric W. Biederman node = hlist_first_rcu(&head->inodes); 2742fd1d2c4SEric W. Biederman if (!node) 2752fd1d2c4SEric W. Biederman break; 2762fd1d2c4SEric W. Biederman ei = hlist_entry(node, struct proc_inode, sysctl_inodes); 2772fd1d2c4SEric W. Biederman spin_lock(&sysctl_lock); 2782fd1d2c4SEric W. Biederman hlist_del_init_rcu(&ei->sysctl_inodes); 2792fd1d2c4SEric W. Biederman spin_unlock(&sysctl_lock); 2802fd1d2c4SEric W. Biederman 2812fd1d2c4SEric W. Biederman inode = &ei->vfs_inode; 2822fd1d2c4SEric W. Biederman sb = inode->i_sb; 2832fd1d2c4SEric W. Biederman if (!atomic_inc_not_zero(&sb->s_active)) 2842fd1d2c4SEric W. Biederman continue; 2852fd1d2c4SEric W. Biederman inode = igrab(inode); 286ace0c791SEric W. Biederman rcu_read_unlock(); 2872fd1d2c4SEric W. Biederman if (unlikely(!inode)) { 2882fd1d2c4SEric W. Biederman deactivate_super(sb); 2892fd1d2c4SEric W. Biederman rcu_read_lock(); 2902fd1d2c4SEric W. Biederman continue; 2912fd1d2c4SEric W. Biederman } 2922fd1d2c4SEric W. Biederman 293d6cffbbeSKonstantin Khlebnikov d_prune_aliases(inode); 2942fd1d2c4SEric W. Biederman iput(inode); 2952fd1d2c4SEric W. Biederman deactivate_super(sb); 2962fd1d2c4SEric W. Biederman 297ace0c791SEric W. Biederman rcu_read_lock(); 298d6cffbbeSKonstantin Khlebnikov } 299ace0c791SEric W. Biederman rcu_read_unlock(); 300d6cffbbeSKonstantin Khlebnikov } 301d6cffbbeSKonstantin Khlebnikov 3021f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 3031f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 3041f87f0b5SEric W. Biederman { 3051f87f0b5SEric W. Biederman /* 3061f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 3071f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 3081f87f0b5SEric W. Biederman */ 3091f87f0b5SEric W. Biederman if (unlikely(p->used)) { 3101f87f0b5SEric W. Biederman struct completion wait; 3111f87f0b5SEric W. Biederman init_completion(&wait); 3121f87f0b5SEric W. Biederman p->unregistering = &wait; 3131f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3141f87f0b5SEric W. Biederman wait_for_completion(&wait); 3151f87f0b5SEric W. Biederman } else { 3161f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3171f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 318ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3191f87f0b5SEric W. Biederman } 3201f87f0b5SEric W. Biederman /* 321d6cffbbeSKonstantin Khlebnikov * Prune dentries for unregistered sysctls: namespaced sysctls 322d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 323d6cffbbeSKonstantin Khlebnikov */ 324d6cffbbeSKonstantin Khlebnikov proc_sys_prune_dcache(p); 325d6cffbbeSKonstantin Khlebnikov /* 3261f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3271f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3281f87f0b5SEric W. Biederman */ 329ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3308425d6aaSEric W. Biederman erase_header(p); 3311f87f0b5SEric W. Biederman } 3321f87f0b5SEric W. Biederman 3331f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3341f87f0b5SEric W. Biederman { 335ab4a1f24SPrasad Joshi BUG_ON(!head); 3361f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3371f87f0b5SEric W. Biederman if (!use_table(head)) 3381f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3391f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3401f87f0b5SEric W. Biederman return head; 3411f87f0b5SEric W. Biederman } 3421f87f0b5SEric W. Biederman 3431f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3441f87f0b5SEric W. Biederman { 3451f87f0b5SEric W. Biederman if (!head) 3461f87f0b5SEric W. Biederman return; 3471f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3481f87f0b5SEric W. Biederman unuse_table(head); 3491f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3501f87f0b5SEric W. Biederman } 3511f87f0b5SEric W. Biederman 3521f87f0b5SEric W. Biederman static struct ctl_table_set * 35313bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3541f87f0b5SEric W. Biederman { 3551f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3561f87f0b5SEric W. Biederman if (root->lookup) 35713bcc6a2SEric W. Biederman set = root->lookup(root); 3581f87f0b5SEric W. Biederman return set; 3591f87f0b5SEric W. Biederman } 3601f87f0b5SEric W. Biederman 361076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3627ec66d06SEric W. Biederman struct ctl_dir *dir, 363076c3eedSEric W. Biederman const char *name, int namelen) 364076c3eedSEric W. Biederman { 365076c3eedSEric W. Biederman struct ctl_table_header *head; 366076c3eedSEric W. Biederman struct ctl_table *entry; 367076c3eedSEric W. Biederman 368076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3690e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 370076c3eedSEric W. Biederman if (entry && use_table(head)) 371076c3eedSEric W. Biederman *phead = head; 372076c3eedSEric W. Biederman else 373076c3eedSEric W. Biederman entry = NULL; 374076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 375076c3eedSEric W. Biederman return entry; 376076c3eedSEric W. Biederman } 377076c3eedSEric W. Biederman 378ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3791f87f0b5SEric W. Biederman { 380ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3811f87f0b5SEric W. Biederman 382ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 383ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 384ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 385ac13ac6fSEric W. Biederman return ctl_node; 3861f87f0b5SEric W. Biederman } 3871f87f0b5SEric W. Biederman return NULL; 3881f87f0b5SEric W. Biederman } 3891f87f0b5SEric W. Biederman 3907ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3916a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3921f87f0b5SEric W. Biederman { 393ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3947ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 395ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3966a75ce16SEric W. Biederman 3976a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 398ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3996a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 400ac13ac6fSEric W. Biederman if (ctl_node) { 401ac13ac6fSEric W. Biederman head = ctl_node->header; 402ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 403ac13ac6fSEric W. Biederman } 4046a75ce16SEric W. Biederman *phead = head; 4056a75ce16SEric W. Biederman *pentry = entry; 4066a75ce16SEric W. Biederman } 4076a75ce16SEric W. Biederman 4087ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 4096a75ce16SEric W. Biederman { 4106a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 4116a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 412ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 4136a75ce16SEric W. Biederman 4146a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 4156a75ce16SEric W. Biederman unuse_table(head); 416ac13ac6fSEric W. Biederman 417ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4186a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 419ac13ac6fSEric W. Biederman head = NULL; 420ac13ac6fSEric W. Biederman if (ctl_node) { 421ac13ac6fSEric W. Biederman head = ctl_node->header; 422ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4236a75ce16SEric W. Biederman } 4246a75ce16SEric W. Biederman *phead = head; 4256a75ce16SEric W. Biederman *pentry = entry; 4261f87f0b5SEric W. Biederman } 4271f87f0b5SEric W. Biederman 4281f87f0b5SEric W. Biederman /* 4291f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4301f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4311f87f0b5SEric W. Biederman */ 4321f87f0b5SEric W. Biederman 4331f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4341f87f0b5SEric W. Biederman { 435091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4361f87f0b5SEric W. Biederman mode >>= 6; 437091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4381f87f0b5SEric W. Biederman mode >>= 3; 4391f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4401f87f0b5SEric W. Biederman return 0; 4411f87f0b5SEric W. Biederman return -EACCES; 4421f87f0b5SEric W. Biederman } 4431f87f0b5SEric W. Biederman 44473f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4451f87f0b5SEric W. Biederman { 44673f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4471f87f0b5SEric W. Biederman int mode; 4481f87f0b5SEric W. Biederman 4491f87f0b5SEric W. Biederman if (root->permissions) 45073f7ef43SEric W. Biederman mode = root->permissions(head, table); 4511f87f0b5SEric W. Biederman else 4521f87f0b5SEric W. Biederman mode = table->mode; 4531f87f0b5SEric W. Biederman 4541f87f0b5SEric W. Biederman return test_perm(mode, op); 4551f87f0b5SEric W. Biederman } 4561f87f0b5SEric W. Biederman 4579043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4589043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 45977b14db5SEric W. Biederman { 460e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 46177b14db5SEric W. Biederman struct inode *inode; 4629043476fSAl Viro struct proc_inode *ei; 46377b14db5SEric W. Biederman 4649043476fSAl Viro inode = new_inode(sb); 46577b14db5SEric W. Biederman if (!inode) 46677b14db5SEric W. Biederman goto out; 46777b14db5SEric W. Biederman 46885fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 46985fe4025SChristoph Hellwig 47077b14db5SEric W. Biederman ei = PROC_I(inode); 4719043476fSAl Viro 472d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 473ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 474ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 475ace0c791SEric W. Biederman iput(inode); 476ace0c791SEric W. Biederman inode = NULL; 477ace0c791SEric W. Biederman goto out; 478ace0c791SEric W. Biederman } 479ace0c791SEric W. Biederman ei->sysctl = head; 480ace0c791SEric W. Biederman ei->sysctl_entry = table; 4812fd1d2c4SEric W. Biederman hlist_add_head_rcu(&ei->sysctl_inodes, &head->inodes); 482d6cffbbeSKonstantin Khlebnikov head->count++; 483d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 484d6cffbbeSKonstantin Khlebnikov 485078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4869043476fSAl Viro inode->i_mode = table->mode; 4877ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4889043476fSAl Viro inode->i_mode |= S_IFREG; 48977b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 49077b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4919043476fSAl Viro } else { 4929043476fSAl Viro inode->i_mode |= S_IFDIR; 4939043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4949043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 495f9bd6733SEric W. Biederman if (is_empty_dir(head)) 496f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4979043476fSAl Viro } 498e79c6a4fSDmitry Torokhov 499e79c6a4fSDmitry Torokhov if (root->set_ownership) 500e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 501e79c6a4fSDmitry Torokhov 50277b14db5SEric W. Biederman out: 50377b14db5SEric W. Biederman return inode; 50477b14db5SEric W. Biederman } 50577b14db5SEric W. Biederman 506d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 507d6cffbbeSKonstantin Khlebnikov { 508d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 5092fd1d2c4SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sysctl_inodes); 510d6cffbbeSKonstantin Khlebnikov if (!--head->count) 511d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 512d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 513d6cffbbeSKonstantin Khlebnikov } 514d6cffbbeSKonstantin Khlebnikov 51581324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 51677b14db5SEric W. Biederman { 5173cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5183cc3e046SEric W. Biederman if (!head) 5190e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5203cc3e046SEric W. Biederman return sysctl_head_grab(head); 52177b14db5SEric W. Biederman } 52277b14db5SEric W. Biederman 52377b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 52400cd8dd3SAl Viro unsigned int flags) 52577b14db5SEric W. Biederman { 5269043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5279043476fSAl Viro struct ctl_table_header *h = NULL; 528dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5299043476fSAl Viro struct ctl_table *p; 53077b14db5SEric W. Biederman struct inode *inode; 5319043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5327ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5330e47c99dSEric W. Biederman int ret; 53477b14db5SEric W. Biederman 5359043476fSAl Viro if (IS_ERR(head)) 5369043476fSAl Viro return ERR_CAST(head); 5379043476fSAl Viro 5387ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5399043476fSAl Viro 5407ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5419043476fSAl Viro if (!p) 54277b14db5SEric W. Biederman goto out; 54377b14db5SEric W. Biederman 5444e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 54513bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5460e47c99dSEric W. Biederman err = ERR_PTR(ret); 5470e47c99dSEric W. Biederman if (ret) 5480e47c99dSEric W. Biederman goto out; 5494e757320SEric W. Biederman } 5500e47c99dSEric W. Biederman 55177b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 5529043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 55377b14db5SEric W. Biederman if (!inode) 55477b14db5SEric W. Biederman goto out; 55577b14db5SEric W. Biederman 55677b14db5SEric W. Biederman err = NULL; 557fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 55877b14db5SEric W. Biederman d_add(dentry, inode); 55977b14db5SEric W. Biederman 56077b14db5SEric W. Biederman out: 5616bf61045SFrancesco Ruggeri if (h) 5626bf61045SFrancesco Ruggeri sysctl_head_finish(h); 56377b14db5SEric W. Biederman sysctl_head_finish(head); 56477b14db5SEric W. Biederman return err; 56577b14db5SEric W. Biederman } 56677b14db5SEric W. Biederman 5677708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 5687708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 56977b14db5SEric W. Biederman { 570496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5719043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5729043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5732a2da53bSDavid Howells ssize_t error; 5742a2da53bSDavid Howells size_t res; 57577b14db5SEric W. Biederman 5769043476fSAl Viro if (IS_ERR(head)) 5779043476fSAl Viro return PTR_ERR(head); 57877b14db5SEric W. Biederman 57977b14db5SEric W. Biederman /* 58077b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 58177b14db5SEric W. Biederman * and won't be until we finish. 58277b14db5SEric W. Biederman */ 58377b14db5SEric W. Biederman error = -EPERM; 58473f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 58577b14db5SEric W. Biederman goto out; 58677b14db5SEric W. Biederman 5879043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5889043476fSAl Viro error = -EINVAL; 5899043476fSAl Viro if (!table->proc_handler) 5909043476fSAl Viro goto out; 5919043476fSAl Viro 59277b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 59377b14db5SEric W. Biederman res = count; 5948d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 59577b14db5SEric W. Biederman if (!error) 59677b14db5SEric W. Biederman error = res; 59777b14db5SEric W. Biederman out: 59877b14db5SEric W. Biederman sysctl_head_finish(head); 59977b14db5SEric W. Biederman 60077b14db5SEric W. Biederman return error; 60177b14db5SEric W. Biederman } 60277b14db5SEric W. Biederman 6037708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 6047708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 6057708bfb1SPavel Emelyanov { 6067708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 6077708bfb1SPavel Emelyanov } 6087708bfb1SPavel Emelyanov 60977b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 61077b14db5SEric W. Biederman size_t count, loff_t *ppos) 61177b14db5SEric W. Biederman { 6127708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 61377b14db5SEric W. Biederman } 61477b14db5SEric W. Biederman 615f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 616f1ecf068SLucas De Marchi { 6174e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 618f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 619f1ecf068SLucas De Marchi 6204e474a00SLucas De Marchi /* sysctl was unregistered */ 6214e474a00SLucas De Marchi if (IS_ERR(head)) 6224e474a00SLucas De Marchi return PTR_ERR(head); 6234e474a00SLucas De Marchi 624f1ecf068SLucas De Marchi if (table->poll) 625f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 626f1ecf068SLucas De Marchi 6274e474a00SLucas De Marchi sysctl_head_finish(head); 6284e474a00SLucas De Marchi 629f1ecf068SLucas De Marchi return 0; 630f1ecf068SLucas De Marchi } 631f1ecf068SLucas De Marchi 632f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 633f1ecf068SLucas De Marchi { 634496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6354e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 636f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 637f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 6384e474a00SLucas De Marchi unsigned long event; 6394e474a00SLucas De Marchi 6404e474a00SLucas De Marchi /* sysctl was unregistered */ 6414e474a00SLucas De Marchi if (IS_ERR(head)) 6424e474a00SLucas De Marchi return POLLERR | POLLHUP; 643f1ecf068SLucas De Marchi 644f1ecf068SLucas De Marchi if (!table->proc_handler) 645f1ecf068SLucas De Marchi goto out; 646f1ecf068SLucas De Marchi 647f1ecf068SLucas De Marchi if (!table->poll) 648f1ecf068SLucas De Marchi goto out; 649f1ecf068SLucas De Marchi 6504e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 651f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 652f1ecf068SLucas De Marchi 653f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 654f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 655f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 656f1ecf068SLucas De Marchi } 657f1ecf068SLucas De Marchi 658f1ecf068SLucas De Marchi out: 6594e474a00SLucas De Marchi sysctl_head_finish(head); 6604e474a00SLucas De Marchi 661f1ecf068SLucas De Marchi return ret; 662f1ecf068SLucas De Marchi } 66377b14db5SEric W. Biederman 664f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 665f0c3b509SAl Viro struct dir_context *ctx, 6669043476fSAl Viro struct ctl_table_header *head, 6679043476fSAl Viro struct ctl_table *table) 66877b14db5SEric W. Biederman { 669f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 67077b14db5SEric W. Biederman struct inode *inode; 67177b14db5SEric W. Biederman struct qstr qname; 67277b14db5SEric W. Biederman ino_t ino = 0; 67377b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 67477b14db5SEric W. Biederman 67577b14db5SEric W. Biederman qname.name = table->procname; 67677b14db5SEric W. Biederman qname.len = strlen(table->procname); 6778387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 67877b14db5SEric W. Biederman 67977b14db5SEric W. Biederman child = d_lookup(dir, &qname); 68077b14db5SEric W. Biederman if (!child) { 68176aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 68276aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 68376aab3abSAl Viro if (IS_ERR(child)) 68476aab3abSAl Viro return false; 68576aab3abSAl Viro if (d_in_lookup(child)) { 6869043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 6879043476fSAl Viro if (!inode) { 68876aab3abSAl Viro d_lookup_done(child); 6899043476fSAl Viro dput(child); 690f0c3b509SAl Viro return false; 69176aab3abSAl Viro } 692fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 6939043476fSAl Viro d_add(child, inode); 69477b14db5SEric W. Biederman } 69577b14db5SEric W. Biederman } 6962b0143b5SDavid Howells inode = d_inode(child); 69777b14db5SEric W. Biederman ino = inode->i_ino; 69877b14db5SEric W. Biederman type = inode->i_mode >> 12; 69977b14db5SEric W. Biederman dput(child); 700f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7019043476fSAl Viro } 7029043476fSAl Viro 703f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 704f0c3b509SAl Viro struct dir_context *ctx, 7050e47c99dSEric W. Biederman struct ctl_table_header *head, 7060e47c99dSEric W. Biederman struct ctl_table *table) 7070e47c99dSEric W. Biederman { 708f0c3b509SAl Viro bool ret = true; 7090e47c99dSEric W. Biederman head = sysctl_head_grab(head); 7100e47c99dSEric W. Biederman 7114e757320SEric W. Biederman if (S_ISLNK(table->mode)) { 7120e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 71313bcc6a2SEric W. Biederman int err = sysctl_follow_link(&head, &table); 7140e47c99dSEric W. Biederman if (err) 7150e47c99dSEric W. Biederman goto out; 7164e757320SEric W. Biederman } 7170e47c99dSEric W. Biederman 718f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7190e47c99dSEric W. Biederman out: 7200e47c99dSEric W. Biederman sysctl_head_finish(head); 7210e47c99dSEric W. Biederman return ret; 7220e47c99dSEric W. Biederman } 7230e47c99dSEric W. Biederman 724e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7259043476fSAl Viro unsigned long *pos, struct file *file, 726f0c3b509SAl Viro struct dir_context *ctx) 7279043476fSAl Viro { 728f0c3b509SAl Viro bool res; 7299043476fSAl Viro 730f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 731f0c3b509SAl Viro return true; 7329043476fSAl Viro 7330e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 734f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7350e47c99dSEric W. Biederman else 736f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7379043476fSAl Viro 738f0c3b509SAl Viro if (res) 739f0c3b509SAl Viro ctx->pos = *pos; 7406a75ce16SEric W. Biederman 7416a75ce16SEric W. Biederman return res; 74277b14db5SEric W. Biederman } 74377b14db5SEric W. Biederman 744f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 74577b14db5SEric W. Biederman { 746f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7479043476fSAl Viro struct ctl_table_header *h = NULL; 7486a75ce16SEric W. Biederman struct ctl_table *entry; 7497ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 75077b14db5SEric W. Biederman unsigned long pos; 75177b14db5SEric W. Biederman 7529043476fSAl Viro if (IS_ERR(head)) 7539043476fSAl Viro return PTR_ERR(head); 7549043476fSAl Viro 7557ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 75677b14db5SEric W. Biederman 757f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 75893362fa4SZhou Chengming goto out; 759f0c3b509SAl Viro 76077b14db5SEric W. Biederman pos = 2; 76177b14db5SEric W. Biederman 7627ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 763f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7649043476fSAl Viro sysctl_head_finish(h); 7659043476fSAl Viro break; 76677b14db5SEric W. Biederman } 76777b14db5SEric W. Biederman } 76893362fa4SZhou Chengming out: 76977b14db5SEric W. Biederman sysctl_head_finish(head); 770f0c3b509SAl Viro return 0; 77177b14db5SEric W. Biederman } 77277b14db5SEric W. Biederman 77310556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 77477b14db5SEric W. Biederman { 77577b14db5SEric W. Biederman /* 77677b14db5SEric W. Biederman * sysctl entries that are not writeable, 77777b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 77877b14db5SEric W. Biederman */ 779f696a365SMiklos Szeredi struct ctl_table_header *head; 780f696a365SMiklos Szeredi struct ctl_table *table; 78177b14db5SEric W. Biederman int error; 78277b14db5SEric W. Biederman 783f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 784f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 785f696a365SMiklos Szeredi return -EACCES; 786f696a365SMiklos Szeredi 787f696a365SMiklos Szeredi head = grab_header(inode); 7889043476fSAl Viro if (IS_ERR(head)) 7899043476fSAl Viro return PTR_ERR(head); 79077b14db5SEric W. Biederman 791f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 7929043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 7939043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 7949043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 79573f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 7969043476fSAl Viro 79777b14db5SEric W. Biederman sysctl_head_finish(head); 79877b14db5SEric W. Biederman return error; 79977b14db5SEric W. Biederman } 80077b14db5SEric W. Biederman 80177b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 80277b14db5SEric W. Biederman { 8032b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 80477b14db5SEric W. Biederman int error; 80577b14db5SEric W. Biederman 80677b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 80777b14db5SEric W. Biederman return -EPERM; 80877b14db5SEric W. Biederman 80931051c85SJan Kara error = setattr_prepare(dentry, attr); 8101025774cSChristoph Hellwig if (error) 81177b14db5SEric W. Biederman return error; 8121025774cSChristoph Hellwig 8131025774cSChristoph Hellwig setattr_copy(inode, attr); 8141025774cSChristoph Hellwig mark_inode_dirty(inode); 8151025774cSChristoph Hellwig return 0; 81677b14db5SEric W. Biederman } 81777b14db5SEric W. Biederman 818a528d35eSDavid Howells static int proc_sys_getattr(const struct path *path, struct kstat *stat, 819a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8209043476fSAl Viro { 821a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8229043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8239043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8249043476fSAl Viro 8259043476fSAl Viro if (IS_ERR(head)) 8269043476fSAl Viro return PTR_ERR(head); 8279043476fSAl Viro 8289043476fSAl Viro generic_fillattr(inode, stat); 8299043476fSAl Viro if (table) 8309043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8319043476fSAl Viro 8329043476fSAl Viro sysctl_head_finish(head); 8339043476fSAl Viro return 0; 8349043476fSAl Viro } 8359043476fSAl Viro 83677b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 837f1ecf068SLucas De Marchi .open = proc_sys_open, 838f1ecf068SLucas De Marchi .poll = proc_sys_poll, 83977b14db5SEric W. Biederman .read = proc_sys_read, 84077b14db5SEric W. Biederman .write = proc_sys_write, 8416038f373SArnd Bergmann .llseek = default_llseek, 8429043476fSAl Viro }; 8439043476fSAl Viro 8449043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 845887df078SPavel Emelyanov .read = generic_read_dir, 846f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8473222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 84877b14db5SEric W. Biederman }; 84977b14db5SEric W. Biederman 85003a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8519043476fSAl Viro .permission = proc_sys_permission, 8529043476fSAl Viro .setattr = proc_sys_setattr, 8539043476fSAl Viro .getattr = proc_sys_getattr, 8549043476fSAl Viro }; 8559043476fSAl Viro 8569043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 85777b14db5SEric W. Biederman .lookup = proc_sys_lookup, 85877b14db5SEric W. Biederman .permission = proc_sys_permission, 85977b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8609043476fSAl Viro .getattr = proc_sys_getattr, 86177b14db5SEric W. Biederman }; 86277b14db5SEric W. Biederman 8630b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 86477b14db5SEric W. Biederman { 8650b728e19SAl Viro if (flags & LOOKUP_RCU) 86634286d66SNick Piggin return -ECHILD; 8672b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8689043476fSAl Viro } 8699043476fSAl Viro 870fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8719043476fSAl Viro { 8722b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 8739043476fSAl Viro } 8749043476fSAl Viro 8751f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8761f87f0b5SEric W. Biederman { 8771f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8781f87f0b5SEric W. Biederman int res; 8791f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8801f87f0b5SEric W. Biederman if (p->unregistering) 8811f87f0b5SEric W. Biederman res = 0; 8821f87f0b5SEric W. Biederman else if (!set->is_seen) 8831f87f0b5SEric W. Biederman res = 1; 8841f87f0b5SEric W. Biederman else 8851f87f0b5SEric W. Biederman res = set->is_seen(set); 8861f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 8871f87f0b5SEric W. Biederman return res; 8881f87f0b5SEric W. Biederman } 8891f87f0b5SEric W. Biederman 8906fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 891621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 8929043476fSAl Viro { 893dfef6dcdSAl Viro struct ctl_table_header *head; 894da53be12SLinus Torvalds struct inode *inode; 895da53be12SLinus Torvalds 89631e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 89731e6b01fSNick Piggin * that inode here can be NULL */ 898dfef6dcdSAl Viro /* AV: can it, indeed? */ 8992b0143b5SDavid Howells inode = d_inode_rcu(dentry); 90031e6b01fSNick Piggin if (!inode) 901dfef6dcdSAl Viro return 1; 902621e155aSNick Piggin if (name->len != len) 9039043476fSAl Viro return 1; 904621e155aSNick Piggin if (memcmp(name->name, str, len)) 9059043476fSAl Viro return 1; 906dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 907dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 90877b14db5SEric W. Biederman } 90977b14db5SEric W. Biederman 910d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 91177b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9129043476fSAl Viro .d_delete = proc_sys_delete, 9139043476fSAl Viro .d_compare = proc_sys_compare, 91477b14db5SEric W. Biederman }; 91577b14db5SEric W. Biederman 9160e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9177ec66d06SEric W. Biederman const char *name, int namelen) 9181f87f0b5SEric W. Biederman { 9197ec66d06SEric W. Biederman struct ctl_table_header *head; 9207ec66d06SEric W. Biederman struct ctl_table *entry; 9211f87f0b5SEric W. Biederman 9220e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9237ec66d06SEric W. Biederman if (!entry) 9247ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 92551f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9267ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 92751f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9281f87f0b5SEric W. Biederman } 9291f87f0b5SEric W. Biederman 9307ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9317ec66d06SEric W. Biederman const char *name, int namelen) 9321f87f0b5SEric W. Biederman { 9337ec66d06SEric W. Biederman struct ctl_table *table; 9347ec66d06SEric W. Biederman struct ctl_dir *new; 935ac13ac6fSEric W. Biederman struct ctl_node *node; 9367ec66d06SEric W. Biederman char *new_name; 9371f87f0b5SEric W. Biederman 938ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 939ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 940ac13ac6fSEric W. Biederman GFP_KERNEL); 9417ec66d06SEric W. Biederman if (!new) 9427ec66d06SEric W. Biederman return NULL; 9437ec66d06SEric W. Biederman 944ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 945ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9467ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9477ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9487ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9497ec66d06SEric W. Biederman table[0].procname = new_name; 9507ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 951ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9527ec66d06SEric W. Biederman 9537ec66d06SEric W. Biederman return new; 9541f87f0b5SEric W. Biederman } 9551f87f0b5SEric W. Biederman 95660f126d9SEric W. Biederman /** 95760f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 95860f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 95960f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 96060f126d9SEric W. Biederman * @namelen: The length of name 96160f126d9SEric W. Biederman * 96260f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 96360f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 96460f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 96560f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 96660f126d9SEric W. Biederman * simply dropped. 96760f126d9SEric W. Biederman */ 9680e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9690e47c99dSEric W. Biederman const char *name, int namelen) 9707ec66d06SEric W. Biederman { 9710e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9727ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9730eb97f38SEric W. Biederman int err; 9747ec66d06SEric W. Biederman 9757ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9760e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9777ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9787ec66d06SEric W. Biederman goto found; 9797ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9807ec66d06SEric W. Biederman goto failed; 9817ec66d06SEric W. Biederman 9827ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9837ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 9847ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9857ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 9867ec66d06SEric W. Biederman if (!new) 9877ec66d06SEric W. Biederman goto failed; 9887ec66d06SEric W. Biederman 98960f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 9900e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9917ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9927ec66d06SEric W. Biederman goto found; 9937ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9947ec66d06SEric W. Biederman goto failed; 9957ec66d06SEric W. Biederman 99660f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 9970eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 9980eb97f38SEric W. Biederman subdir = ERR_PTR(err); 9990eb97f38SEric W. Biederman if (err) 10000e47c99dSEric W. Biederman goto failed; 10017ec66d06SEric W. Biederman subdir = new; 10027ec66d06SEric W. Biederman found: 10037ec66d06SEric W. Biederman subdir->header.nreg++; 10047ec66d06SEric W. Biederman failed: 1005a1c83681SViresh Kumar if (IS_ERR(subdir)) { 100687ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10076980128fSEric W. Biederman sysctl_print_dir(dir); 100887ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 10097ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 10101f87f0b5SEric W. Biederman } 10117ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10127ec66d06SEric W. Biederman if (new) 10137ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10147ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10157ec66d06SEric W. Biederman return subdir; 10161f87f0b5SEric W. Biederman } 10171f87f0b5SEric W. Biederman 10180e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10190e47c99dSEric W. Biederman { 10200e47c99dSEric W. Biederman struct ctl_dir *parent; 10210e47c99dSEric W. Biederman const char *procname; 10220e47c99dSEric W. Biederman if (!dir->header.parent) 10230e47c99dSEric W. Biederman return &set->dir; 10240e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10250e47c99dSEric W. Biederman if (IS_ERR(parent)) 10260e47c99dSEric W. Biederman return parent; 10270e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10280e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10290e47c99dSEric W. Biederman } 10300e47c99dSEric W. Biederman 10310e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 103213bcc6a2SEric W. Biederman struct ctl_table **pentry) 10330e47c99dSEric W. Biederman { 10340e47c99dSEric W. Biederman struct ctl_table_header *head; 10350e47c99dSEric W. Biederman struct ctl_table_root *root; 10360e47c99dSEric W. Biederman struct ctl_table_set *set; 10370e47c99dSEric W. Biederman struct ctl_table *entry; 10380e47c99dSEric W. Biederman struct ctl_dir *dir; 10390e47c99dSEric W. Biederman int ret; 10400e47c99dSEric W. Biederman 10410e47c99dSEric W. Biederman ret = 0; 10420e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10430e47c99dSEric W. Biederman root = (*pentry)->data; 104413bcc6a2SEric W. Biederman set = lookup_header_set(root); 10450e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10460e47c99dSEric W. Biederman if (IS_ERR(dir)) 10470e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10480e47c99dSEric W. Biederman else { 10490e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10500e47c99dSEric W. Biederman head = NULL; 10510e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10520e47c99dSEric W. Biederman ret = -ENOENT; 10530e47c99dSEric W. Biederman if (entry && use_table(head)) { 10540e47c99dSEric W. Biederman unuse_table(*phead); 10550e47c99dSEric W. Biederman *phead = head; 10560e47c99dSEric W. Biederman *pentry = entry; 10570e47c99dSEric W. Biederman ret = 0; 10580e47c99dSEric W. Biederman } 10590e47c99dSEric W. Biederman } 10600e47c99dSEric W. Biederman 10610e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10620e47c99dSEric W. Biederman return ret; 10630e47c99dSEric W. Biederman } 10640e47c99dSEric W. Biederman 10657c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10667c60c48fSEric W. Biederman { 10677c60c48fSEric W. Biederman struct va_format vaf; 10687c60c48fSEric W. Biederman va_list args; 10697c60c48fSEric W. Biederman 10707c60c48fSEric W. Biederman va_start(args, fmt); 10717c60c48fSEric W. Biederman vaf.fmt = fmt; 10727c60c48fSEric W. Biederman vaf.va = &args; 10737c60c48fSEric W. Biederman 107487ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10757c60c48fSEric W. Biederman path, table->procname, &vaf); 10767c60c48fSEric W. Biederman 10777c60c48fSEric W. Biederman va_end(args); 10787c60c48fSEric W. Biederman return -EINVAL; 10797c60c48fSEric W. Biederman } 10807c60c48fSEric W. Biederman 10817c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 10827c60c48fSEric W. Biederman { 10837c60c48fSEric W. Biederman int err = 0; 10847c60c48fSEric W. Biederman for (; table->procname; table++) { 10857c60c48fSEric W. Biederman if (table->child) 10867c60c48fSEric W. Biederman err = sysctl_err(path, table, "Not a file"); 10877c60c48fSEric W. Biederman 10881f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 10891f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 10901680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 10911f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 10921f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 10931f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 10941f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 10951f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 10961f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 10971f87f0b5SEric W. Biederman if (!table->data) 10987c60c48fSEric W. Biederman err = sysctl_err(path, table, "No data"); 10991f87f0b5SEric W. Biederman if (!table->maxlen) 11007c60c48fSEric W. Biederman err = sysctl_err(path, table, "No maxlen"); 11011f87f0b5SEric W. Biederman } 11021f87f0b5SEric W. Biederman if (!table->proc_handler) 11037c60c48fSEric W. Biederman err = sysctl_err(path, table, "No proc_handler"); 11047c60c48fSEric W. Biederman 11057c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 11067c60c48fSEric W. Biederman err = sysctl_err(path, table, "bogus .mode 0%o", 11077c60c48fSEric W. Biederman table->mode); 11081f87f0b5SEric W. Biederman } 11097c60c48fSEric W. Biederman return err; 11101f87f0b5SEric W. Biederman } 11111f87f0b5SEric W. Biederman 11120e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11130e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11140e47c99dSEric W. Biederman { 11150e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11160e47c99dSEric W. Biederman struct ctl_table_header *links; 1117ac13ac6fSEric W. Biederman struct ctl_node *node; 11180e47c99dSEric W. Biederman char *link_name; 11190e47c99dSEric W. Biederman int nr_entries, name_bytes; 11200e47c99dSEric W. Biederman 11210e47c99dSEric W. Biederman name_bytes = 0; 11220e47c99dSEric W. Biederman nr_entries = 0; 11230e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11240e47c99dSEric W. Biederman nr_entries++; 11250e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11260e47c99dSEric W. Biederman } 11270e47c99dSEric W. Biederman 11280e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1129ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11300e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11310e47c99dSEric W. Biederman name_bytes, 11320e47c99dSEric W. Biederman GFP_KERNEL); 11330e47c99dSEric W. Biederman 11340e47c99dSEric W. Biederman if (!links) 11350e47c99dSEric W. Biederman return NULL; 11360e47c99dSEric W. Biederman 1137ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1138ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11390e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11400e47c99dSEric W. Biederman 11410e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11420e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11430e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11440e47c99dSEric W. Biederman link->procname = link_name; 11450e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11460e47c99dSEric W. Biederman link->data = link_root; 11470e47c99dSEric W. Biederman link_name += len; 11480e47c99dSEric W. Biederman } 1149ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11500e47c99dSEric W. Biederman links->nreg = nr_entries; 11510e47c99dSEric W. Biederman 11520e47c99dSEric W. Biederman return links; 11530e47c99dSEric W. Biederman } 11540e47c99dSEric W. Biederman 11550e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11560e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11570e47c99dSEric W. Biederman { 11580e47c99dSEric W. Biederman struct ctl_table_header *head; 11590e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11600e47c99dSEric W. Biederman 11610e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11620e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11630e47c99dSEric W. Biederman const char *procname = entry->procname; 11640e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11650e47c99dSEric W. Biederman if (!link) 11660e47c99dSEric W. Biederman return false; 11670e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 11680e47c99dSEric W. Biederman continue; 11690e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 11700e47c99dSEric W. Biederman continue; 11710e47c99dSEric W. Biederman return false; 11720e47c99dSEric W. Biederman } 11730e47c99dSEric W. Biederman 11740e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 11750e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11760e47c99dSEric W. Biederman const char *procname = entry->procname; 11770e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11780e47c99dSEric W. Biederman head->nreg++; 11790e47c99dSEric W. Biederman } 11800e47c99dSEric W. Biederman return true; 11810e47c99dSEric W. Biederman } 11820e47c99dSEric W. Biederman 11830e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 11840e47c99dSEric W. Biederman { 11850e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 11860e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 11870e47c99dSEric W. Biederman struct ctl_table_header *links; 11880e47c99dSEric W. Biederman int err; 11890e47c99dSEric W. Biederman 11900e47c99dSEric W. Biederman if (head->set == root_set) 11910e47c99dSEric W. Biederman return 0; 11920e47c99dSEric W. Biederman 11930e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 11940e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 11950e47c99dSEric W. Biederman return 0; 11960e47c99dSEric W. Biederman 11970e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 11980e47c99dSEric W. Biederman return 0; 11990e47c99dSEric W. Biederman 12000e47c99dSEric W. Biederman core_parent->header.nreg++; 12010e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12020e47c99dSEric W. Biederman 12030e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12040e47c99dSEric W. Biederman 12050e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12060e47c99dSEric W. Biederman err = -ENOMEM; 12070e47c99dSEric W. Biederman if (!links) 12080e47c99dSEric W. Biederman goto out; 12090e47c99dSEric W. Biederman 12100e47c99dSEric W. Biederman err = 0; 12110e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12120e47c99dSEric W. Biederman kfree(links); 12130e47c99dSEric W. Biederman goto out; 12140e47c99dSEric W. Biederman } 12150e47c99dSEric W. Biederman 12160e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12170e47c99dSEric W. Biederman if (err) 12180e47c99dSEric W. Biederman kfree(links); 12190e47c99dSEric W. Biederman out: 12200e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12210e47c99dSEric W. Biederman return err; 12220e47c99dSEric W. Biederman } 12230e47c99dSEric W. Biederman 12241f87f0b5SEric W. Biederman /** 1225f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 122660a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12271f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12281f87f0b5SEric W. Biederman * @table: the top-level table structure 12291f87f0b5SEric W. Biederman * 12301f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12311f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12321f87f0b5SEric W. Biederman * 12331f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12341f87f0b5SEric W. Biederman * 12351f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12361f87f0b5SEric W. Biederman * enter a sysctl file 12371f87f0b5SEric W. Biederman * 12381f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12391f87f0b5SEric W. Biederman * 12401f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12411f87f0b5SEric W. Biederman * 1242f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12431f87f0b5SEric W. Biederman * 1244f728019bSEric W. Biederman * child - must be %NULL. 12451f87f0b5SEric W. Biederman * 12461f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12471f87f0b5SEric W. Biederman * 12481f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12491f87f0b5SEric W. Biederman * 12501f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12511f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12521f87f0b5SEric W. Biederman * 1253f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1254f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12551f87f0b5SEric W. Biederman * 12561f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12571f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12581f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12591f87f0b5SEric W. Biederman * 12601f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12611f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12621f87f0b5SEric W. Biederman * 12631f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 12641f87f0b5SEric W. Biederman * to the table header on success. 12651f87f0b5SEric W. Biederman */ 12666e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 126760a47a2eSEric W. Biederman struct ctl_table_set *set, 12686e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 12691f87f0b5SEric W. Biederman { 127060a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 12711f87f0b5SEric W. Biederman struct ctl_table_header *header; 12726e9d5164SEric W. Biederman const char *name, *nextname; 12737ec66d06SEric W. Biederman struct ctl_dir *dir; 1274ac13ac6fSEric W. Biederman struct ctl_table *entry; 1275ac13ac6fSEric W. Biederman struct ctl_node *node; 1276ac13ac6fSEric W. Biederman int nr_entries = 0; 12771f87f0b5SEric W. Biederman 1278ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1279ac13ac6fSEric W. Biederman nr_entries++; 1280ac13ac6fSEric W. Biederman 1281ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1282ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 12831f87f0b5SEric W. Biederman if (!header) 12841f87f0b5SEric W. Biederman return NULL; 12851f87f0b5SEric W. Biederman 1286ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1287ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 12887c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 12897c60c48fSEric W. Biederman goto fail; 12908d6ecfccSEric W. Biederman 12911f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 12920e47c99dSEric W. Biederman dir = &set->dir; 129360f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 12947ec66d06SEric W. Biederman dir->header.nreg++; 12957ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 12967ec66d06SEric W. Biederman 12977ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 12987ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 12997ec66d06SEric W. Biederman int namelen; 13007ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13017ec66d06SEric W. Biederman if (nextname) { 13027ec66d06SEric W. Biederman namelen = nextname - name; 13037ec66d06SEric W. Biederman nextname++; 13047ec66d06SEric W. Biederman } else { 13057ec66d06SEric W. Biederman namelen = strlen(name); 13067ec66d06SEric W. Biederman } 13077ec66d06SEric W. Biederman if (namelen == 0) 13081f87f0b5SEric W. Biederman continue; 13097ec66d06SEric W. Biederman 13100e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13117ec66d06SEric W. Biederman if (IS_ERR(dir)) 13127ec66d06SEric W. Biederman goto fail; 13131f87f0b5SEric W. Biederman } 13140e47c99dSEric W. Biederman 13157ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13160e47c99dSEric W. Biederman if (insert_header(dir, header)) 13170e47c99dSEric W. Biederman goto fail_put_dir_locked; 13180e47c99dSEric W. Biederman 13197ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13201f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13211f87f0b5SEric W. Biederman 13221f87f0b5SEric W. Biederman return header; 13230e47c99dSEric W. Biederman 13247ec66d06SEric W. Biederman fail_put_dir_locked: 13257ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13267c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13277c60c48fSEric W. Biederman fail: 13287c60c48fSEric W. Biederman kfree(header); 13297c60c48fSEric W. Biederman dump_stack(); 13307c60c48fSEric W. Biederman return NULL; 13311f87f0b5SEric W. Biederman } 13321f87f0b5SEric W. Biederman 1333fea478d4SEric W. Biederman /** 1334fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1335fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1336fea478d4SEric W. Biederman * @table: the table structure 1337fea478d4SEric W. Biederman * 1338fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1339fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1340fea478d4SEric W. Biederman * 1341fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1342fea478d4SEric W. Biederman */ 1343fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1344fea478d4SEric W. Biederman { 1345fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1346fea478d4SEric W. Biederman path, table); 1347fea478d4SEric W. Biederman } 1348fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1349fea478d4SEric W. Biederman 13506e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 13516e9d5164SEric W. Biederman { 13526e9d5164SEric W. Biederman int namelen; 13536e9d5164SEric W. Biederman namelen = strlen(name); 13546e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 13556e9d5164SEric W. Biederman return NULL; 13566e9d5164SEric W. Biederman memcpy(pos, name, namelen); 13576e9d5164SEric W. Biederman pos[namelen] = '/'; 13586e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 13596e9d5164SEric W. Biederman pos += namelen + 1; 13606e9d5164SEric W. Biederman return pos; 13616e9d5164SEric W. Biederman } 13626e9d5164SEric W. Biederman 1363f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1364f728019bSEric W. Biederman { 1365f728019bSEric W. Biederman int has_files = 0; 1366f728019bSEric W. Biederman int nr_subheaders = 0; 1367f728019bSEric W. Biederman struct ctl_table *entry; 1368f728019bSEric W. Biederman 1369f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1370f728019bSEric W. Biederman if (!table || !table->procname) 1371f728019bSEric W. Biederman return 1; 1372f728019bSEric W. Biederman 1373f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1374f728019bSEric W. Biederman if (entry->child) 1375f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1376f728019bSEric W. Biederman else 1377f728019bSEric W. Biederman has_files = 1; 1378f728019bSEric W. Biederman } 1379f728019bSEric W. Biederman return nr_subheaders + has_files; 1380f728019bSEric W. Biederman } 1381f728019bSEric W. Biederman 1382f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 138360a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1384f728019bSEric W. Biederman struct ctl_table *table) 1385f728019bSEric W. Biederman { 1386f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1387f728019bSEric W. Biederman struct ctl_table *entry, *files; 1388f728019bSEric W. Biederman int nr_files = 0; 1389f728019bSEric W. Biederman int nr_dirs = 0; 1390f728019bSEric W. Biederman int err = -ENOMEM; 1391f728019bSEric W. Biederman 1392f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1393f728019bSEric W. Biederman if (entry->child) 1394f728019bSEric W. Biederman nr_dirs++; 1395f728019bSEric W. Biederman else 1396f728019bSEric W. Biederman nr_files++; 1397f728019bSEric W. Biederman } 1398f728019bSEric W. Biederman 1399f728019bSEric W. Biederman files = table; 1400f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1401f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1402f728019bSEric W. Biederman struct ctl_table *new; 1403f728019bSEric W. Biederman files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), 1404f728019bSEric W. Biederman GFP_KERNEL); 1405f728019bSEric W. Biederman if (!files) 1406f728019bSEric W. Biederman goto out; 1407f728019bSEric W. Biederman 1408f728019bSEric W. Biederman ctl_table_arg = files; 1409f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1410f728019bSEric W. Biederman if (entry->child) 1411f728019bSEric W. Biederman continue; 1412f728019bSEric W. Biederman *new = *entry; 1413f728019bSEric W. Biederman new++; 1414f728019bSEric W. Biederman } 1415f728019bSEric W. Biederman } 1416f728019bSEric W. Biederman 1417f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1418f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1419f728019bSEric W. Biederman struct ctl_table_header *header; 142060a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1421f728019bSEric W. Biederman if (!header) { 1422f728019bSEric W. Biederman kfree(ctl_table_arg); 1423f728019bSEric W. Biederman goto out; 1424f728019bSEric W. Biederman } 1425f728019bSEric W. Biederman 1426f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1427f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1428f728019bSEric W. Biederman **subheader = header; 1429f728019bSEric W. Biederman (*subheader)++; 1430f728019bSEric W. Biederman } 1431f728019bSEric W. Biederman 1432f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1433f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1434f728019bSEric W. Biederman char *child_pos; 1435f728019bSEric W. Biederman 1436f728019bSEric W. Biederman if (!entry->child) 1437f728019bSEric W. Biederman continue; 1438f728019bSEric W. Biederman 1439f728019bSEric W. Biederman err = -ENAMETOOLONG; 1440f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1441f728019bSEric W. Biederman if (!child_pos) 1442f728019bSEric W. Biederman goto out; 1443f728019bSEric W. Biederman 1444f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 144560a47a2eSEric W. Biederman set, entry->child); 1446f728019bSEric W. Biederman pos[0] = '\0'; 1447f728019bSEric W. Biederman if (err) 1448f728019bSEric W. Biederman goto out; 1449f728019bSEric W. Biederman } 1450f728019bSEric W. Biederman err = 0; 1451f728019bSEric W. Biederman out: 1452f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1453f728019bSEric W. Biederman return err; 1454f728019bSEric W. Biederman } 1455f728019bSEric W. Biederman 14566e9d5164SEric W. Biederman /** 14576e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 145860a47a2eSEric W. Biederman * @set: Sysctl tree to register on 14596e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14606e9d5164SEric W. Biederman * @table: the top-level table structure 14616e9d5164SEric W. Biederman * 14626e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14636e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14646e9d5164SEric W. Biederman * 14656e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 14666e9d5164SEric W. Biederman */ 14676e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 146860a47a2eSEric W. Biederman struct ctl_table_set *set, 14696e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 14706e9d5164SEric W. Biederman { 1471ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1472f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1473f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 14746e9d5164SEric W. Biederman const struct ctl_path *component; 14756e9d5164SEric W. Biederman char *new_path, *pos; 14766e9d5164SEric W. Biederman 14776e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 14786e9d5164SEric W. Biederman if (!new_path) 14796e9d5164SEric W. Biederman return NULL; 14806e9d5164SEric W. Biederman 14816e9d5164SEric W. Biederman pos[0] = '\0'; 14826e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 14836e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 14846e9d5164SEric W. Biederman if (!pos) 14856e9d5164SEric W. Biederman goto out; 14866e9d5164SEric W. Biederman } 1487ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1488ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1489ec6a5266SEric W. Biederman if (!pos) 1490ec6a5266SEric W. Biederman goto out; 1491ec6a5266SEric W. Biederman table = table->child; 1492ec6a5266SEric W. Biederman } 1493f728019bSEric W. Biederman if (nr_subheaders == 1) { 149460a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1495ec6a5266SEric W. Biederman if (header) 1496ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1497f728019bSEric W. Biederman } else { 1498f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1499f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1500f728019bSEric W. Biederman if (!header) 1501f728019bSEric W. Biederman goto out; 1502f728019bSEric W. Biederman 1503f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1504f728019bSEric W. Biederman subheader = subheaders; 1505f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1506f728019bSEric W. Biederman 1507f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 150860a47a2eSEric W. Biederman set, table)) 1509f728019bSEric W. Biederman goto err_register_leaves; 1510f728019bSEric W. Biederman } 1511f728019bSEric W. Biederman 15126e9d5164SEric W. Biederman out: 15136e9d5164SEric W. Biederman kfree(new_path); 15146e9d5164SEric W. Biederman return header; 1515f728019bSEric W. Biederman 1516f728019bSEric W. Biederman err_register_leaves: 1517f728019bSEric W. Biederman while (subheader > subheaders) { 1518f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1519f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1520f728019bSEric W. Biederman unregister_sysctl_table(subh); 1521f728019bSEric W. Biederman kfree(table); 1522f728019bSEric W. Biederman } 1523f728019bSEric W. Biederman kfree(header); 1524f728019bSEric W. Biederman header = NULL; 1525f728019bSEric W. Biederman goto out; 15266e9d5164SEric W. Biederman } 15276e9d5164SEric W. Biederman 15281f87f0b5SEric W. Biederman /** 15291f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 15301f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15311f87f0b5SEric W. Biederman * @table: the top-level table structure 15321f87f0b5SEric W. Biederman * 15331f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15341f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15351f87f0b5SEric W. Biederman * 15361f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 15371f87f0b5SEric W. Biederman */ 15381f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 15391f87f0b5SEric W. Biederman struct ctl_table *table) 15401f87f0b5SEric W. Biederman { 154160a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 15421f87f0b5SEric W. Biederman path, table); 15431f87f0b5SEric W. Biederman } 15441f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 15451f87f0b5SEric W. Biederman 15461f87f0b5SEric W. Biederman /** 15471f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 15481f87f0b5SEric W. Biederman * @table: the top-level table structure 15491f87f0b5SEric W. Biederman * 15501f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15511f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15521f87f0b5SEric W. Biederman * 15531f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 15541f87f0b5SEric W. Biederman */ 15551f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 15561f87f0b5SEric W. Biederman { 15571f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 15581f87f0b5SEric W. Biederman 15591f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 15601f87f0b5SEric W. Biederman } 15611f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 15621f87f0b5SEric W. Biederman 15630e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 15640e47c99dSEric W. Biederman { 15650e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 15660e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 15670e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 15680e47c99dSEric W. Biederman struct ctl_dir *core_parent; 15690e47c99dSEric W. Biederman struct ctl_table *entry; 15700e47c99dSEric W. Biederman 15710e47c99dSEric W. Biederman if (header->set == root_set) 15720e47c99dSEric W. Biederman return; 15730e47c99dSEric W. Biederman 15740e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 15750e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 15760e47c99dSEric W. Biederman return; 15770e47c99dSEric W. Biederman 15780e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 15790e47c99dSEric W. Biederman struct ctl_table_header *link_head; 15800e47c99dSEric W. Biederman struct ctl_table *link; 15810e47c99dSEric W. Biederman const char *name = entry->procname; 15820e47c99dSEric W. Biederman 15830e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 15840e47c99dSEric W. Biederman if (link && 15850e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 15860e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 15870e47c99dSEric W. Biederman drop_sysctl_table(link_head); 15880e47c99dSEric W. Biederman } 15890e47c99dSEric W. Biederman else { 159087ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 15910e47c99dSEric W. Biederman sysctl_print_dir(parent); 159287ebdc00SAndrew Morton pr_cont("/%s\n", name); 15930e47c99dSEric W. Biederman } 15940e47c99dSEric W. Biederman } 15950e47c99dSEric W. Biederman } 15960e47c99dSEric W. Biederman 1597938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1598938aaa4fSEric W. Biederman { 15997ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 16007ec66d06SEric W. Biederman 1601938aaa4fSEric W. Biederman if (--header->nreg) 1602938aaa4fSEric W. Biederman return; 1603938aaa4fSEric W. Biederman 16040e47c99dSEric W. Biederman put_links(header); 1605938aaa4fSEric W. Biederman start_unregistering(header); 1606938aaa4fSEric W. Biederman if (!--header->count) 1607938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16087ec66d06SEric W. Biederman 16097ec66d06SEric W. Biederman if (parent) 16107ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1611938aaa4fSEric W. Biederman } 1612938aaa4fSEric W. Biederman 16131f87f0b5SEric W. Biederman /** 16141f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16151f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16161f87f0b5SEric W. Biederman * 16171f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16181f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16191f87f0b5SEric W. Biederman */ 16201f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16211f87f0b5SEric W. Biederman { 1622f728019bSEric W. Biederman int nr_subheaders; 16231f87f0b5SEric W. Biederman might_sleep(); 16241f87f0b5SEric W. Biederman 16251f87f0b5SEric W. Biederman if (header == NULL) 16261f87f0b5SEric W. Biederman return; 16271f87f0b5SEric W. Biederman 1628f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1629f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1630f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1631f728019bSEric W. Biederman int i; 1632f728019bSEric W. Biederman 1633f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1634f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1635f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1636f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1637f728019bSEric W. Biederman unregister_sysctl_table(subh); 1638f728019bSEric W. Biederman kfree(table); 1639f728019bSEric W. Biederman } 1640f728019bSEric W. Biederman kfree(header); 1641f728019bSEric W. Biederman return; 1642f728019bSEric W. Biederman } 1643f728019bSEric W. Biederman 16441f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1645938aaa4fSEric W. Biederman drop_sysctl_table(header); 16461f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 16471f87f0b5SEric W. Biederman } 16481f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 16491f87f0b5SEric W. Biederman 16500e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 16519eb47c26SEric W. Biederman struct ctl_table_root *root, 16521f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 16531f87f0b5SEric W. Biederman { 16541347440dSDan Carpenter memset(set, 0, sizeof(*set)); 16550e47c99dSEric W. Biederman set->is_seen = is_seen; 1656ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 16571f87f0b5SEric W. Biederman } 16581f87f0b5SEric W. Biederman 165997324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 166097324cd8SEric W. Biederman { 1661ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 166297324cd8SEric W. Biederman } 16631f87f0b5SEric W. Biederman 16641e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 166577b14db5SEric W. Biederman { 1666e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1667e1675231SAlexey Dobriyan 166877b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 16699043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 16709043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 167177b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1672de4e83bdSEric W. Biederman 1673de4e83bdSEric W. Biederman return sysctl_init(); 167477b14db5SEric W. Biederman } 1675