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; 194d6cffbbeSKonstantin Khlebnikov INIT_LIST_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 /* called under sysctl_lock */ 265d6cffbbeSKonstantin Khlebnikov static void proc_sys_prune_dcache(struct ctl_table_header *head) 266d6cffbbeSKonstantin Khlebnikov { 267d6cffbbeSKonstantin Khlebnikov struct inode *inode, *prev = NULL; 268d6cffbbeSKonstantin Khlebnikov struct proc_inode *ei; 269d6cffbbeSKonstantin Khlebnikov 270ace0c791SEric W. Biederman rcu_read_lock(); 271ace0c791SEric W. Biederman list_for_each_entry_rcu(ei, &head->inodes, sysctl_inodes) { 272d6cffbbeSKonstantin Khlebnikov inode = igrab(&ei->vfs_inode); 273d6cffbbeSKonstantin Khlebnikov if (inode) { 274ace0c791SEric W. Biederman rcu_read_unlock(); 275d6cffbbeSKonstantin Khlebnikov iput(prev); 276d6cffbbeSKonstantin Khlebnikov prev = inode; 277d6cffbbeSKonstantin Khlebnikov d_prune_aliases(inode); 278ace0c791SEric W. Biederman rcu_read_lock(); 279d6cffbbeSKonstantin Khlebnikov } 280d6cffbbeSKonstantin Khlebnikov } 281ace0c791SEric W. Biederman rcu_read_unlock(); 282d6cffbbeSKonstantin Khlebnikov iput(prev); 283d6cffbbeSKonstantin Khlebnikov } 284d6cffbbeSKonstantin Khlebnikov 2851f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2861f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2871f87f0b5SEric W. Biederman { 2881f87f0b5SEric W. Biederman /* 2891f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2901f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2911f87f0b5SEric W. Biederman */ 2921f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2931f87f0b5SEric W. Biederman struct completion wait; 2941f87f0b5SEric W. Biederman init_completion(&wait); 2951f87f0b5SEric W. Biederman p->unregistering = &wait; 2961f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2971f87f0b5SEric W. Biederman wait_for_completion(&wait); 2981f87f0b5SEric W. Biederman } else { 2991f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3001f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 301ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3021f87f0b5SEric W. Biederman } 3031f87f0b5SEric W. Biederman /* 304d6cffbbeSKonstantin Khlebnikov * Prune dentries for unregistered sysctls: namespaced sysctls 305d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 306d6cffbbeSKonstantin Khlebnikov */ 307d6cffbbeSKonstantin Khlebnikov proc_sys_prune_dcache(p); 308d6cffbbeSKonstantin Khlebnikov /* 3091f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3101f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3111f87f0b5SEric W. Biederman */ 312ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3138425d6aaSEric W. Biederman erase_header(p); 3141f87f0b5SEric W. Biederman } 3151f87f0b5SEric W. Biederman 3161f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3171f87f0b5SEric W. Biederman { 318ab4a1f24SPrasad Joshi BUG_ON(!head); 3191f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3201f87f0b5SEric W. Biederman if (!use_table(head)) 3211f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3221f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3231f87f0b5SEric W. Biederman return head; 3241f87f0b5SEric W. Biederman } 3251f87f0b5SEric W. Biederman 3261f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3271f87f0b5SEric W. Biederman { 3281f87f0b5SEric W. Biederman if (!head) 3291f87f0b5SEric W. Biederman return; 3301f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3311f87f0b5SEric W. Biederman unuse_table(head); 3321f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3331f87f0b5SEric W. Biederman } 3341f87f0b5SEric W. Biederman 3351f87f0b5SEric W. Biederman static struct ctl_table_set * 33613bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3371f87f0b5SEric W. Biederman { 3381f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3391f87f0b5SEric W. Biederman if (root->lookup) 34013bcc6a2SEric W. Biederman set = root->lookup(root); 3411f87f0b5SEric W. Biederman return set; 3421f87f0b5SEric W. Biederman } 3431f87f0b5SEric W. Biederman 344076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3457ec66d06SEric W. Biederman struct ctl_dir *dir, 346076c3eedSEric W. Biederman const char *name, int namelen) 347076c3eedSEric W. Biederman { 348076c3eedSEric W. Biederman struct ctl_table_header *head; 349076c3eedSEric W. Biederman struct ctl_table *entry; 350076c3eedSEric W. Biederman 351076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3520e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 353076c3eedSEric W. Biederman if (entry && use_table(head)) 354076c3eedSEric W. Biederman *phead = head; 355076c3eedSEric W. Biederman else 356076c3eedSEric W. Biederman entry = NULL; 357076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 358076c3eedSEric W. Biederman return entry; 359076c3eedSEric W. Biederman } 360076c3eedSEric W. Biederman 361ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3621f87f0b5SEric W. Biederman { 363ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3641f87f0b5SEric W. Biederman 365ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 366ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 367ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 368ac13ac6fSEric W. Biederman return ctl_node; 3691f87f0b5SEric W. Biederman } 3701f87f0b5SEric W. Biederman return NULL; 3711f87f0b5SEric W. Biederman } 3721f87f0b5SEric W. Biederman 3737ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3746a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3751f87f0b5SEric W. Biederman { 376ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3777ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 378ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3796a75ce16SEric W. Biederman 3806a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 381ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3826a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 383ac13ac6fSEric W. Biederman if (ctl_node) { 384ac13ac6fSEric W. Biederman head = ctl_node->header; 385ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 386ac13ac6fSEric W. Biederman } 3876a75ce16SEric W. Biederman *phead = head; 3886a75ce16SEric W. Biederman *pentry = entry; 3896a75ce16SEric W. Biederman } 3906a75ce16SEric W. Biederman 3917ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3926a75ce16SEric W. Biederman { 3936a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3946a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 395ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 3966a75ce16SEric W. Biederman 3976a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 3986a75ce16SEric W. Biederman unuse_table(head); 399ac13ac6fSEric W. Biederman 400ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4016a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 402ac13ac6fSEric W. Biederman head = NULL; 403ac13ac6fSEric W. Biederman if (ctl_node) { 404ac13ac6fSEric W. Biederman head = ctl_node->header; 405ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4066a75ce16SEric W. Biederman } 4076a75ce16SEric W. Biederman *phead = head; 4086a75ce16SEric W. Biederman *pentry = entry; 4091f87f0b5SEric W. Biederman } 4101f87f0b5SEric W. Biederman 4111f87f0b5SEric W. Biederman /* 4121f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4131f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4141f87f0b5SEric W. Biederman */ 4151f87f0b5SEric W. Biederman 4161f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4171f87f0b5SEric W. Biederman { 418091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4191f87f0b5SEric W. Biederman mode >>= 6; 420091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4211f87f0b5SEric W. Biederman mode >>= 3; 4221f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4231f87f0b5SEric W. Biederman return 0; 4241f87f0b5SEric W. Biederman return -EACCES; 4251f87f0b5SEric W. Biederman } 4261f87f0b5SEric W. Biederman 42773f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4281f87f0b5SEric W. Biederman { 42973f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4301f87f0b5SEric W. Biederman int mode; 4311f87f0b5SEric W. Biederman 4321f87f0b5SEric W. Biederman if (root->permissions) 43373f7ef43SEric W. Biederman mode = root->permissions(head, table); 4341f87f0b5SEric W. Biederman else 4351f87f0b5SEric W. Biederman mode = table->mode; 4361f87f0b5SEric W. Biederman 4371f87f0b5SEric W. Biederman return test_perm(mode, op); 4381f87f0b5SEric W. Biederman } 4391f87f0b5SEric W. Biederman 4409043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4419043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 44277b14db5SEric W. Biederman { 443e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 44477b14db5SEric W. Biederman struct inode *inode; 4459043476fSAl Viro struct proc_inode *ei; 44677b14db5SEric W. Biederman 4479043476fSAl Viro inode = new_inode(sb); 44877b14db5SEric W. Biederman if (!inode) 44977b14db5SEric W. Biederman goto out; 45077b14db5SEric W. Biederman 45185fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 45285fe4025SChristoph Hellwig 45377b14db5SEric W. Biederman ei = PROC_I(inode); 4549043476fSAl Viro 455d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 456ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 457ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 458ace0c791SEric W. Biederman iput(inode); 459ace0c791SEric W. Biederman inode = NULL; 460ace0c791SEric W. Biederman goto out; 461ace0c791SEric W. Biederman } 462ace0c791SEric W. Biederman ei->sysctl = head; 463ace0c791SEric W. Biederman ei->sysctl_entry = table; 464ace0c791SEric W. Biederman list_add_rcu(&ei->sysctl_inodes, &head->inodes); 465d6cffbbeSKonstantin Khlebnikov head->count++; 466d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 467d6cffbbeSKonstantin Khlebnikov 468078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4699043476fSAl Viro inode->i_mode = table->mode; 4707ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4719043476fSAl Viro inode->i_mode |= S_IFREG; 47277b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 47377b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4749043476fSAl Viro } else { 4759043476fSAl Viro inode->i_mode |= S_IFDIR; 4769043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4779043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 478f9bd6733SEric W. Biederman if (is_empty_dir(head)) 479f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4809043476fSAl Viro } 481e79c6a4fSDmitry Torokhov 482e79c6a4fSDmitry Torokhov if (root->set_ownership) 483e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 484e79c6a4fSDmitry Torokhov 48577b14db5SEric W. Biederman out: 48677b14db5SEric W. Biederman return inode; 48777b14db5SEric W. Biederman } 48877b14db5SEric W. Biederman 489d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 490d6cffbbeSKonstantin Khlebnikov { 491d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 492ace0c791SEric W. Biederman list_del_rcu(&PROC_I(inode)->sysctl_inodes); 493d6cffbbeSKonstantin Khlebnikov if (!--head->count) 494d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 495d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 496d6cffbbeSKonstantin Khlebnikov } 497d6cffbbeSKonstantin Khlebnikov 49881324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 49977b14db5SEric W. Biederman { 5003cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5013cc3e046SEric W. Biederman if (!head) 5020e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5033cc3e046SEric W. Biederman return sysctl_head_grab(head); 50477b14db5SEric W. Biederman } 50577b14db5SEric W. Biederman 50677b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 50700cd8dd3SAl Viro unsigned int flags) 50877b14db5SEric W. Biederman { 5099043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5109043476fSAl Viro struct ctl_table_header *h = NULL; 511dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5129043476fSAl Viro struct ctl_table *p; 51377b14db5SEric W. Biederman struct inode *inode; 5149043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5157ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5160e47c99dSEric W. Biederman int ret; 51777b14db5SEric W. Biederman 5189043476fSAl Viro if (IS_ERR(head)) 5199043476fSAl Viro return ERR_CAST(head); 5209043476fSAl Viro 5217ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5229043476fSAl Viro 5237ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5249043476fSAl Viro if (!p) 52577b14db5SEric W. Biederman goto out; 52677b14db5SEric W. Biederman 5274e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 52813bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5290e47c99dSEric W. Biederman err = ERR_PTR(ret); 5300e47c99dSEric W. Biederman if (ret) 5310e47c99dSEric W. Biederman goto out; 5324e757320SEric W. Biederman } 5330e47c99dSEric W. Biederman 53477b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 5359043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 53677b14db5SEric W. Biederman if (!inode) 53777b14db5SEric W. Biederman goto out; 53877b14db5SEric W. Biederman 53977b14db5SEric W. Biederman err = NULL; 540fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 54177b14db5SEric W. Biederman d_add(dentry, inode); 54277b14db5SEric W. Biederman 54377b14db5SEric W. Biederman out: 5446bf61045SFrancesco Ruggeri if (h) 5456bf61045SFrancesco Ruggeri sysctl_head_finish(h); 54677b14db5SEric W. Biederman sysctl_head_finish(head); 54777b14db5SEric W. Biederman return err; 54877b14db5SEric W. Biederman } 54977b14db5SEric W. Biederman 5507708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 5517708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 55277b14db5SEric W. Biederman { 553496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5549043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5559043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5562a2da53bSDavid Howells ssize_t error; 5572a2da53bSDavid Howells size_t res; 55877b14db5SEric W. Biederman 5599043476fSAl Viro if (IS_ERR(head)) 5609043476fSAl Viro return PTR_ERR(head); 56177b14db5SEric W. Biederman 56277b14db5SEric W. Biederman /* 56377b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 56477b14db5SEric W. Biederman * and won't be until we finish. 56577b14db5SEric W. Biederman */ 56677b14db5SEric W. Biederman error = -EPERM; 56773f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 56877b14db5SEric W. Biederman goto out; 56977b14db5SEric W. Biederman 5709043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5719043476fSAl Viro error = -EINVAL; 5729043476fSAl Viro if (!table->proc_handler) 5739043476fSAl Viro goto out; 5749043476fSAl Viro 57577b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 57677b14db5SEric W. Biederman res = count; 5778d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 57877b14db5SEric W. Biederman if (!error) 57977b14db5SEric W. Biederman error = res; 58077b14db5SEric W. Biederman out: 58177b14db5SEric W. Biederman sysctl_head_finish(head); 58277b14db5SEric W. Biederman 58377b14db5SEric W. Biederman return error; 58477b14db5SEric W. Biederman } 58577b14db5SEric W. Biederman 5867708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 5877708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 5887708bfb1SPavel Emelyanov { 5897708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 5907708bfb1SPavel Emelyanov } 5917708bfb1SPavel Emelyanov 59277b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 59377b14db5SEric W. Biederman size_t count, loff_t *ppos) 59477b14db5SEric W. Biederman { 5957708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 59677b14db5SEric W. Biederman } 59777b14db5SEric W. Biederman 598f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 599f1ecf068SLucas De Marchi { 6004e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 601f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 602f1ecf068SLucas De Marchi 6034e474a00SLucas De Marchi /* sysctl was unregistered */ 6044e474a00SLucas De Marchi if (IS_ERR(head)) 6054e474a00SLucas De Marchi return PTR_ERR(head); 6064e474a00SLucas De Marchi 607f1ecf068SLucas De Marchi if (table->poll) 608f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 609f1ecf068SLucas De Marchi 6104e474a00SLucas De Marchi sysctl_head_finish(head); 6114e474a00SLucas De Marchi 612f1ecf068SLucas De Marchi return 0; 613f1ecf068SLucas De Marchi } 614f1ecf068SLucas De Marchi 615f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 616f1ecf068SLucas De Marchi { 617496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6184e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 619f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 620f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 6214e474a00SLucas De Marchi unsigned long event; 6224e474a00SLucas De Marchi 6234e474a00SLucas De Marchi /* sysctl was unregistered */ 6244e474a00SLucas De Marchi if (IS_ERR(head)) 6254e474a00SLucas De Marchi return POLLERR | POLLHUP; 626f1ecf068SLucas De Marchi 627f1ecf068SLucas De Marchi if (!table->proc_handler) 628f1ecf068SLucas De Marchi goto out; 629f1ecf068SLucas De Marchi 630f1ecf068SLucas De Marchi if (!table->poll) 631f1ecf068SLucas De Marchi goto out; 632f1ecf068SLucas De Marchi 6334e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 634f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 635f1ecf068SLucas De Marchi 636f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 637f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 638f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 639f1ecf068SLucas De Marchi } 640f1ecf068SLucas De Marchi 641f1ecf068SLucas De Marchi out: 6424e474a00SLucas De Marchi sysctl_head_finish(head); 6434e474a00SLucas De Marchi 644f1ecf068SLucas De Marchi return ret; 645f1ecf068SLucas De Marchi } 64677b14db5SEric W. Biederman 647f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 648f0c3b509SAl Viro struct dir_context *ctx, 6499043476fSAl Viro struct ctl_table_header *head, 6509043476fSAl Viro struct ctl_table *table) 65177b14db5SEric W. Biederman { 652f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 65377b14db5SEric W. Biederman struct inode *inode; 65477b14db5SEric W. Biederman struct qstr qname; 65577b14db5SEric W. Biederman ino_t ino = 0; 65677b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 65777b14db5SEric W. Biederman 65877b14db5SEric W. Biederman qname.name = table->procname; 65977b14db5SEric W. Biederman qname.len = strlen(table->procname); 6608387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 66177b14db5SEric W. Biederman 66277b14db5SEric W. Biederman child = d_lookup(dir, &qname); 66377b14db5SEric W. Biederman if (!child) { 66476aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 66576aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 66676aab3abSAl Viro if (IS_ERR(child)) 66776aab3abSAl Viro return false; 66876aab3abSAl Viro if (d_in_lookup(child)) { 6699043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 6709043476fSAl Viro if (!inode) { 67176aab3abSAl Viro d_lookup_done(child); 6729043476fSAl Viro dput(child); 673f0c3b509SAl Viro return false; 67476aab3abSAl Viro } 675fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 6769043476fSAl Viro d_add(child, inode); 67777b14db5SEric W. Biederman } 67877b14db5SEric W. Biederman } 6792b0143b5SDavid Howells inode = d_inode(child); 68077b14db5SEric W. Biederman ino = inode->i_ino; 68177b14db5SEric W. Biederman type = inode->i_mode >> 12; 68277b14db5SEric W. Biederman dput(child); 683f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 6849043476fSAl Viro } 6859043476fSAl Viro 686f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 687f0c3b509SAl Viro struct dir_context *ctx, 6880e47c99dSEric W. Biederman struct ctl_table_header *head, 6890e47c99dSEric W. Biederman struct ctl_table *table) 6900e47c99dSEric W. Biederman { 691f0c3b509SAl Viro bool ret = true; 6920e47c99dSEric W. Biederman head = sysctl_head_grab(head); 6930e47c99dSEric W. Biederman 6944e757320SEric W. Biederman if (S_ISLNK(table->mode)) { 6950e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 69613bcc6a2SEric W. Biederman int err = sysctl_follow_link(&head, &table); 6970e47c99dSEric W. Biederman if (err) 6980e47c99dSEric W. Biederman goto out; 6994e757320SEric W. Biederman } 7000e47c99dSEric W. Biederman 701f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7020e47c99dSEric W. Biederman out: 7030e47c99dSEric W. Biederman sysctl_head_finish(head); 7040e47c99dSEric W. Biederman return ret; 7050e47c99dSEric W. Biederman } 7060e47c99dSEric W. Biederman 707e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7089043476fSAl Viro unsigned long *pos, struct file *file, 709f0c3b509SAl Viro struct dir_context *ctx) 7109043476fSAl Viro { 711f0c3b509SAl Viro bool res; 7129043476fSAl Viro 713f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 714f0c3b509SAl Viro return true; 7159043476fSAl Viro 7160e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 717f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7180e47c99dSEric W. Biederman else 719f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7209043476fSAl Viro 721f0c3b509SAl Viro if (res) 722f0c3b509SAl Viro ctx->pos = *pos; 7236a75ce16SEric W. Biederman 7246a75ce16SEric W. Biederman return res; 72577b14db5SEric W. Biederman } 72677b14db5SEric W. Biederman 727f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 72877b14db5SEric W. Biederman { 729f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7309043476fSAl Viro struct ctl_table_header *h = NULL; 7316a75ce16SEric W. Biederman struct ctl_table *entry; 7327ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 73377b14db5SEric W. Biederman unsigned long pos; 73477b14db5SEric W. Biederman 7359043476fSAl Viro if (IS_ERR(head)) 7369043476fSAl Viro return PTR_ERR(head); 7379043476fSAl Viro 7387ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 73977b14db5SEric W. Biederman 740f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 74193362fa4SZhou Chengming goto out; 742f0c3b509SAl Viro 74377b14db5SEric W. Biederman pos = 2; 74477b14db5SEric W. Biederman 7457ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 746f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7479043476fSAl Viro sysctl_head_finish(h); 7489043476fSAl Viro break; 74977b14db5SEric W. Biederman } 75077b14db5SEric W. Biederman } 75193362fa4SZhou Chengming out: 75277b14db5SEric W. Biederman sysctl_head_finish(head); 753f0c3b509SAl Viro return 0; 75477b14db5SEric W. Biederman } 75577b14db5SEric W. Biederman 75610556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 75777b14db5SEric W. Biederman { 75877b14db5SEric W. Biederman /* 75977b14db5SEric W. Biederman * sysctl entries that are not writeable, 76077b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 76177b14db5SEric W. Biederman */ 762f696a365SMiklos Szeredi struct ctl_table_header *head; 763f696a365SMiklos Szeredi struct ctl_table *table; 76477b14db5SEric W. Biederman int error; 76577b14db5SEric W. Biederman 766f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 767f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 768f696a365SMiklos Szeredi return -EACCES; 769f696a365SMiklos Szeredi 770f696a365SMiklos Szeredi head = grab_header(inode); 7719043476fSAl Viro if (IS_ERR(head)) 7729043476fSAl Viro return PTR_ERR(head); 77377b14db5SEric W. Biederman 774f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 7759043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 7769043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 7779043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 77873f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 7799043476fSAl Viro 78077b14db5SEric W. Biederman sysctl_head_finish(head); 78177b14db5SEric W. Biederman return error; 78277b14db5SEric W. Biederman } 78377b14db5SEric W. Biederman 78477b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 78577b14db5SEric W. Biederman { 7862b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 78777b14db5SEric W. Biederman int error; 78877b14db5SEric W. Biederman 78977b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 79077b14db5SEric W. Biederman return -EPERM; 79177b14db5SEric W. Biederman 79231051c85SJan Kara error = setattr_prepare(dentry, attr); 7931025774cSChristoph Hellwig if (error) 79477b14db5SEric W. Biederman return error; 7951025774cSChristoph Hellwig 7961025774cSChristoph Hellwig setattr_copy(inode, attr); 7971025774cSChristoph Hellwig mark_inode_dirty(inode); 7981025774cSChristoph Hellwig return 0; 79977b14db5SEric W. Biederman } 80077b14db5SEric W. Biederman 801a528d35eSDavid Howells static int proc_sys_getattr(const struct path *path, struct kstat *stat, 802a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8039043476fSAl Viro { 804a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8059043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8069043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8079043476fSAl Viro 8089043476fSAl Viro if (IS_ERR(head)) 8099043476fSAl Viro return PTR_ERR(head); 8109043476fSAl Viro 8119043476fSAl Viro generic_fillattr(inode, stat); 8129043476fSAl Viro if (table) 8139043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8149043476fSAl Viro 8159043476fSAl Viro sysctl_head_finish(head); 8169043476fSAl Viro return 0; 8179043476fSAl Viro } 8189043476fSAl Viro 81977b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 820f1ecf068SLucas De Marchi .open = proc_sys_open, 821f1ecf068SLucas De Marchi .poll = proc_sys_poll, 82277b14db5SEric W. Biederman .read = proc_sys_read, 82377b14db5SEric W. Biederman .write = proc_sys_write, 8246038f373SArnd Bergmann .llseek = default_llseek, 8259043476fSAl Viro }; 8269043476fSAl Viro 8279043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 828887df078SPavel Emelyanov .read = generic_read_dir, 829f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8303222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 83177b14db5SEric W. Biederman }; 83277b14db5SEric W. Biederman 83303a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8349043476fSAl Viro .permission = proc_sys_permission, 8359043476fSAl Viro .setattr = proc_sys_setattr, 8369043476fSAl Viro .getattr = proc_sys_getattr, 8379043476fSAl Viro }; 8389043476fSAl Viro 8399043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 84077b14db5SEric W. Biederman .lookup = proc_sys_lookup, 84177b14db5SEric W. Biederman .permission = proc_sys_permission, 84277b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8439043476fSAl Viro .getattr = proc_sys_getattr, 84477b14db5SEric W. Biederman }; 84577b14db5SEric W. Biederman 8460b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 84777b14db5SEric W. Biederman { 8480b728e19SAl Viro if (flags & LOOKUP_RCU) 84934286d66SNick Piggin return -ECHILD; 8502b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8519043476fSAl Viro } 8529043476fSAl Viro 853fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8549043476fSAl Viro { 8552b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 8569043476fSAl Viro } 8579043476fSAl Viro 8581f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8591f87f0b5SEric W. Biederman { 8601f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8611f87f0b5SEric W. Biederman int res; 8621f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8631f87f0b5SEric W. Biederman if (p->unregistering) 8641f87f0b5SEric W. Biederman res = 0; 8651f87f0b5SEric W. Biederman else if (!set->is_seen) 8661f87f0b5SEric W. Biederman res = 1; 8671f87f0b5SEric W. Biederman else 8681f87f0b5SEric W. Biederman res = set->is_seen(set); 8691f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 8701f87f0b5SEric W. Biederman return res; 8711f87f0b5SEric W. Biederman } 8721f87f0b5SEric W. Biederman 8736fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 874621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 8759043476fSAl Viro { 876dfef6dcdSAl Viro struct ctl_table_header *head; 877da53be12SLinus Torvalds struct inode *inode; 878da53be12SLinus Torvalds 87931e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 88031e6b01fSNick Piggin * that inode here can be NULL */ 881dfef6dcdSAl Viro /* AV: can it, indeed? */ 8822b0143b5SDavid Howells inode = d_inode_rcu(dentry); 88331e6b01fSNick Piggin if (!inode) 884dfef6dcdSAl Viro return 1; 885621e155aSNick Piggin if (name->len != len) 8869043476fSAl Viro return 1; 887621e155aSNick Piggin if (memcmp(name->name, str, len)) 8889043476fSAl Viro return 1; 889dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 890dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 89177b14db5SEric W. Biederman } 89277b14db5SEric W. Biederman 893d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 89477b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 8959043476fSAl Viro .d_delete = proc_sys_delete, 8969043476fSAl Viro .d_compare = proc_sys_compare, 89777b14db5SEric W. Biederman }; 89877b14db5SEric W. Biederman 8990e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9007ec66d06SEric W. Biederman const char *name, int namelen) 9011f87f0b5SEric W. Biederman { 9027ec66d06SEric W. Biederman struct ctl_table_header *head; 9037ec66d06SEric W. Biederman struct ctl_table *entry; 9041f87f0b5SEric W. Biederman 9050e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9067ec66d06SEric W. Biederman if (!entry) 9077ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 90851f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9097ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 91051f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9111f87f0b5SEric W. Biederman } 9121f87f0b5SEric W. Biederman 9137ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9147ec66d06SEric W. Biederman const char *name, int namelen) 9151f87f0b5SEric W. Biederman { 9167ec66d06SEric W. Biederman struct ctl_table *table; 9177ec66d06SEric W. Biederman struct ctl_dir *new; 918ac13ac6fSEric W. Biederman struct ctl_node *node; 9197ec66d06SEric W. Biederman char *new_name; 9201f87f0b5SEric W. Biederman 921ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 922ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 923ac13ac6fSEric W. Biederman GFP_KERNEL); 9247ec66d06SEric W. Biederman if (!new) 9257ec66d06SEric W. Biederman return NULL; 9267ec66d06SEric W. Biederman 927ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 928ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9297ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9307ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9317ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9327ec66d06SEric W. Biederman table[0].procname = new_name; 9337ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 934ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9357ec66d06SEric W. Biederman 9367ec66d06SEric W. Biederman return new; 9371f87f0b5SEric W. Biederman } 9381f87f0b5SEric W. Biederman 93960f126d9SEric W. Biederman /** 94060f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 94160f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 94260f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 94360f126d9SEric W. Biederman * @namelen: The length of name 94460f126d9SEric W. Biederman * 94560f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 94660f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 94760f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 94860f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 94960f126d9SEric W. Biederman * simply dropped. 95060f126d9SEric W. Biederman */ 9510e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9520e47c99dSEric W. Biederman const char *name, int namelen) 9537ec66d06SEric W. Biederman { 9540e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9557ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9560eb97f38SEric W. Biederman int err; 9577ec66d06SEric W. Biederman 9587ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9590e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9607ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9617ec66d06SEric W. Biederman goto found; 9627ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9637ec66d06SEric W. Biederman goto failed; 9647ec66d06SEric W. Biederman 9657ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9667ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 9677ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9687ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 9697ec66d06SEric W. Biederman if (!new) 9707ec66d06SEric W. Biederman goto failed; 9717ec66d06SEric W. Biederman 97260f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 9730e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9747ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9757ec66d06SEric W. Biederman goto found; 9767ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9777ec66d06SEric W. Biederman goto failed; 9787ec66d06SEric W. Biederman 97960f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 9800eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 9810eb97f38SEric W. Biederman subdir = ERR_PTR(err); 9820eb97f38SEric W. Biederman if (err) 9830e47c99dSEric W. Biederman goto failed; 9847ec66d06SEric W. Biederman subdir = new; 9857ec66d06SEric W. Biederman found: 9867ec66d06SEric W. Biederman subdir->header.nreg++; 9877ec66d06SEric W. Biederman failed: 988a1c83681SViresh Kumar if (IS_ERR(subdir)) { 98987ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 9906980128fSEric W. Biederman sysctl_print_dir(dir); 99187ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 9927ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 9931f87f0b5SEric W. Biederman } 9947ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 9957ec66d06SEric W. Biederman if (new) 9967ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 9977ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9987ec66d06SEric W. Biederman return subdir; 9991f87f0b5SEric W. Biederman } 10001f87f0b5SEric W. Biederman 10010e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10020e47c99dSEric W. Biederman { 10030e47c99dSEric W. Biederman struct ctl_dir *parent; 10040e47c99dSEric W. Biederman const char *procname; 10050e47c99dSEric W. Biederman if (!dir->header.parent) 10060e47c99dSEric W. Biederman return &set->dir; 10070e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10080e47c99dSEric W. Biederman if (IS_ERR(parent)) 10090e47c99dSEric W. Biederman return parent; 10100e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10110e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10120e47c99dSEric W. Biederman } 10130e47c99dSEric W. Biederman 10140e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 101513bcc6a2SEric W. Biederman struct ctl_table **pentry) 10160e47c99dSEric W. Biederman { 10170e47c99dSEric W. Biederman struct ctl_table_header *head; 10180e47c99dSEric W. Biederman struct ctl_table_root *root; 10190e47c99dSEric W. Biederman struct ctl_table_set *set; 10200e47c99dSEric W. Biederman struct ctl_table *entry; 10210e47c99dSEric W. Biederman struct ctl_dir *dir; 10220e47c99dSEric W. Biederman int ret; 10230e47c99dSEric W. Biederman 10240e47c99dSEric W. Biederman ret = 0; 10250e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10260e47c99dSEric W. Biederman root = (*pentry)->data; 102713bcc6a2SEric W. Biederman set = lookup_header_set(root); 10280e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10290e47c99dSEric W. Biederman if (IS_ERR(dir)) 10300e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10310e47c99dSEric W. Biederman else { 10320e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10330e47c99dSEric W. Biederman head = NULL; 10340e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10350e47c99dSEric W. Biederman ret = -ENOENT; 10360e47c99dSEric W. Biederman if (entry && use_table(head)) { 10370e47c99dSEric W. Biederman unuse_table(*phead); 10380e47c99dSEric W. Biederman *phead = head; 10390e47c99dSEric W. Biederman *pentry = entry; 10400e47c99dSEric W. Biederman ret = 0; 10410e47c99dSEric W. Biederman } 10420e47c99dSEric W. Biederman } 10430e47c99dSEric W. Biederman 10440e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10450e47c99dSEric W. Biederman return ret; 10460e47c99dSEric W. Biederman } 10470e47c99dSEric W. Biederman 10487c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10497c60c48fSEric W. Biederman { 10507c60c48fSEric W. Biederman struct va_format vaf; 10517c60c48fSEric W. Biederman va_list args; 10527c60c48fSEric W. Biederman 10537c60c48fSEric W. Biederman va_start(args, fmt); 10547c60c48fSEric W. Biederman vaf.fmt = fmt; 10557c60c48fSEric W. Biederman vaf.va = &args; 10567c60c48fSEric W. Biederman 105787ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10587c60c48fSEric W. Biederman path, table->procname, &vaf); 10597c60c48fSEric W. Biederman 10607c60c48fSEric W. Biederman va_end(args); 10617c60c48fSEric W. Biederman return -EINVAL; 10627c60c48fSEric W. Biederman } 10637c60c48fSEric W. Biederman 10644f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 10654f2fec00SLuis R. Rodriguez { 10664f2fec00SLuis R. Rodriguez int err = 0; 10674f2fec00SLuis R. Rodriguez 106861d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 106961d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 10704f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 10714f2fec00SLuis R. Rodriguez err |= sysctl_err(path, table, "array now allowed"); 10724f2fec00SLuis R. Rodriguez } 10734f2fec00SLuis R. Rodriguez 10744f2fec00SLuis R. Rodriguez return err; 10754f2fec00SLuis R. Rodriguez } 10764f2fec00SLuis R. Rodriguez 10777c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 10787c60c48fSEric W. Biederman { 10797c60c48fSEric W. Biederman int err = 0; 10807c60c48fSEric W. Biederman for (; table->procname; table++) { 10817c60c48fSEric W. Biederman if (table->child) 108289c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "Not a file"); 10837c60c48fSEric W. Biederman 10841f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 10851f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 10861680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 108761d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax) || 10881f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 10891f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 10901f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 10911f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 10921f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 10931f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 10941f87f0b5SEric W. Biederman if (!table->data) 109589c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No data"); 10961f87f0b5SEric W. Biederman if (!table->maxlen) 109789c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No maxlen"); 10984f2fec00SLuis R. Rodriguez else 10994f2fec00SLuis R. Rodriguez err |= sysctl_check_table_array(path, table); 11001f87f0b5SEric W. Biederman } 11011f87f0b5SEric W. Biederman if (!table->proc_handler) 110289c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No proc_handler"); 11037c60c48fSEric W. Biederman 11047c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 110589c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "bogus .mode 0%o", 11067c60c48fSEric W. Biederman table->mode); 11071f87f0b5SEric W. Biederman } 11087c60c48fSEric W. Biederman return err; 11091f87f0b5SEric W. Biederman } 11101f87f0b5SEric W. Biederman 11110e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11120e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11130e47c99dSEric W. Biederman { 11140e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11150e47c99dSEric W. Biederman struct ctl_table_header *links; 1116ac13ac6fSEric W. Biederman struct ctl_node *node; 11170e47c99dSEric W. Biederman char *link_name; 11180e47c99dSEric W. Biederman int nr_entries, name_bytes; 11190e47c99dSEric W. Biederman 11200e47c99dSEric W. Biederman name_bytes = 0; 11210e47c99dSEric W. Biederman nr_entries = 0; 11220e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11230e47c99dSEric W. Biederman nr_entries++; 11240e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11250e47c99dSEric W. Biederman } 11260e47c99dSEric W. Biederman 11270e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1128ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11290e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11300e47c99dSEric W. Biederman name_bytes, 11310e47c99dSEric W. Biederman GFP_KERNEL); 11320e47c99dSEric W. Biederman 11330e47c99dSEric W. Biederman if (!links) 11340e47c99dSEric W. Biederman return NULL; 11350e47c99dSEric W. Biederman 1136ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1137ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11380e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11390e47c99dSEric W. Biederman 11400e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11410e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11420e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11430e47c99dSEric W. Biederman link->procname = link_name; 11440e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11450e47c99dSEric W. Biederman link->data = link_root; 11460e47c99dSEric W. Biederman link_name += len; 11470e47c99dSEric W. Biederman } 1148ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11490e47c99dSEric W. Biederman links->nreg = nr_entries; 11500e47c99dSEric W. Biederman 11510e47c99dSEric W. Biederman return links; 11520e47c99dSEric W. Biederman } 11530e47c99dSEric W. Biederman 11540e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11550e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11560e47c99dSEric W. Biederman { 11570e47c99dSEric W. Biederman struct ctl_table_header *head; 11580e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11590e47c99dSEric W. Biederman 11600e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11610e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11620e47c99dSEric W. Biederman const char *procname = entry->procname; 11630e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11640e47c99dSEric W. Biederman if (!link) 11650e47c99dSEric W. Biederman return false; 11660e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 11670e47c99dSEric W. Biederman continue; 11680e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 11690e47c99dSEric W. Biederman continue; 11700e47c99dSEric W. Biederman return false; 11710e47c99dSEric W. Biederman } 11720e47c99dSEric W. Biederman 11730e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 11740e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11750e47c99dSEric W. Biederman const char *procname = entry->procname; 11760e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11770e47c99dSEric W. Biederman head->nreg++; 11780e47c99dSEric W. Biederman } 11790e47c99dSEric W. Biederman return true; 11800e47c99dSEric W. Biederman } 11810e47c99dSEric W. Biederman 11820e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 11830e47c99dSEric W. Biederman { 11840e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 11850e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 11860e47c99dSEric W. Biederman struct ctl_table_header *links; 11870e47c99dSEric W. Biederman int err; 11880e47c99dSEric W. Biederman 11890e47c99dSEric W. Biederman if (head->set == root_set) 11900e47c99dSEric W. Biederman return 0; 11910e47c99dSEric W. Biederman 11920e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 11930e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 11940e47c99dSEric W. Biederman return 0; 11950e47c99dSEric W. Biederman 11960e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 11970e47c99dSEric W. Biederman return 0; 11980e47c99dSEric W. Biederman 11990e47c99dSEric W. Biederman core_parent->header.nreg++; 12000e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12010e47c99dSEric W. Biederman 12020e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12030e47c99dSEric W. Biederman 12040e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12050e47c99dSEric W. Biederman err = -ENOMEM; 12060e47c99dSEric W. Biederman if (!links) 12070e47c99dSEric W. Biederman goto out; 12080e47c99dSEric W. Biederman 12090e47c99dSEric W. Biederman err = 0; 12100e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12110e47c99dSEric W. Biederman kfree(links); 12120e47c99dSEric W. Biederman goto out; 12130e47c99dSEric W. Biederman } 12140e47c99dSEric W. Biederman 12150e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12160e47c99dSEric W. Biederman if (err) 12170e47c99dSEric W. Biederman kfree(links); 12180e47c99dSEric W. Biederman out: 12190e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12200e47c99dSEric W. Biederman return err; 12210e47c99dSEric W. Biederman } 12220e47c99dSEric W. Biederman 12231f87f0b5SEric W. Biederman /** 1224f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 122560a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12261f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12271f87f0b5SEric W. Biederman * @table: the top-level table structure 12281f87f0b5SEric W. Biederman * 12291f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12301f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12311f87f0b5SEric W. Biederman * 12321f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12331f87f0b5SEric W. Biederman * 12341f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12351f87f0b5SEric W. Biederman * enter a sysctl file 12361f87f0b5SEric W. Biederman * 12371f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12381f87f0b5SEric W. Biederman * 12391f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12401f87f0b5SEric W. Biederman * 1241f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12421f87f0b5SEric W. Biederman * 1243f728019bSEric W. Biederman * child - must be %NULL. 12441f87f0b5SEric W. Biederman * 12451f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12461f87f0b5SEric W. Biederman * 12471f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12481f87f0b5SEric W. Biederman * 12491f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12501f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12511f87f0b5SEric W. Biederman * 1252f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1253f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12541f87f0b5SEric W. Biederman * 12551f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12561f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12571f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12581f87f0b5SEric W. Biederman * 12591f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12601f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12611f87f0b5SEric W. Biederman * 12621f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 12631f87f0b5SEric W. Biederman * to the table header on success. 12641f87f0b5SEric W. Biederman */ 12656e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 126660a47a2eSEric W. Biederman struct ctl_table_set *set, 12676e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 12681f87f0b5SEric W. Biederman { 126960a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 12701f87f0b5SEric W. Biederman struct ctl_table_header *header; 12716e9d5164SEric W. Biederman const char *name, *nextname; 12727ec66d06SEric W. Biederman struct ctl_dir *dir; 1273ac13ac6fSEric W. Biederman struct ctl_table *entry; 1274ac13ac6fSEric W. Biederman struct ctl_node *node; 1275ac13ac6fSEric W. Biederman int nr_entries = 0; 12761f87f0b5SEric W. Biederman 1277ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1278ac13ac6fSEric W. Biederman nr_entries++; 1279ac13ac6fSEric W. Biederman 1280ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1281ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 12821f87f0b5SEric W. Biederman if (!header) 12831f87f0b5SEric W. Biederman return NULL; 12841f87f0b5SEric W. Biederman 1285ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1286ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 12877c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 12887c60c48fSEric W. Biederman goto fail; 12898d6ecfccSEric W. Biederman 12901f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 12910e47c99dSEric W. Biederman dir = &set->dir; 129260f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 12937ec66d06SEric W. Biederman dir->header.nreg++; 12947ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 12957ec66d06SEric W. Biederman 12967ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 12977ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 12987ec66d06SEric W. Biederman int namelen; 12997ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13007ec66d06SEric W. Biederman if (nextname) { 13017ec66d06SEric W. Biederman namelen = nextname - name; 13027ec66d06SEric W. Biederman nextname++; 13037ec66d06SEric W. Biederman } else { 13047ec66d06SEric W. Biederman namelen = strlen(name); 13057ec66d06SEric W. Biederman } 13067ec66d06SEric W. Biederman if (namelen == 0) 13071f87f0b5SEric W. Biederman continue; 13087ec66d06SEric W. Biederman 13090e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13107ec66d06SEric W. Biederman if (IS_ERR(dir)) 13117ec66d06SEric W. Biederman goto fail; 13121f87f0b5SEric W. Biederman } 13130e47c99dSEric W. Biederman 13147ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13150e47c99dSEric W. Biederman if (insert_header(dir, header)) 13160e47c99dSEric W. Biederman goto fail_put_dir_locked; 13170e47c99dSEric W. Biederman 13187ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13191f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13201f87f0b5SEric W. Biederman 13211f87f0b5SEric W. Biederman return header; 13220e47c99dSEric W. Biederman 13237ec66d06SEric W. Biederman fail_put_dir_locked: 13247ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13257c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13267c60c48fSEric W. Biederman fail: 13277c60c48fSEric W. Biederman kfree(header); 13287c60c48fSEric W. Biederman dump_stack(); 13297c60c48fSEric W. Biederman return NULL; 13301f87f0b5SEric W. Biederman } 13311f87f0b5SEric W. Biederman 1332fea478d4SEric W. Biederman /** 1333fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1334fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1335fea478d4SEric W. Biederman * @table: the table structure 1336fea478d4SEric W. Biederman * 1337fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1338fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1339fea478d4SEric W. Biederman * 1340fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1341fea478d4SEric W. Biederman */ 1342fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1343fea478d4SEric W. Biederman { 1344fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1345fea478d4SEric W. Biederman path, table); 1346fea478d4SEric W. Biederman } 1347fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1348fea478d4SEric W. Biederman 13496e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 13506e9d5164SEric W. Biederman { 13516e9d5164SEric W. Biederman int namelen; 13526e9d5164SEric W. Biederman namelen = strlen(name); 13536e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 13546e9d5164SEric W. Biederman return NULL; 13556e9d5164SEric W. Biederman memcpy(pos, name, namelen); 13566e9d5164SEric W. Biederman pos[namelen] = '/'; 13576e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 13586e9d5164SEric W. Biederman pos += namelen + 1; 13596e9d5164SEric W. Biederman return pos; 13606e9d5164SEric W. Biederman } 13616e9d5164SEric W. Biederman 1362f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1363f728019bSEric W. Biederman { 1364f728019bSEric W. Biederman int has_files = 0; 1365f728019bSEric W. Biederman int nr_subheaders = 0; 1366f728019bSEric W. Biederman struct ctl_table *entry; 1367f728019bSEric W. Biederman 1368f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1369f728019bSEric W. Biederman if (!table || !table->procname) 1370f728019bSEric W. Biederman return 1; 1371f728019bSEric W. Biederman 1372f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1373f728019bSEric W. Biederman if (entry->child) 1374f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1375f728019bSEric W. Biederman else 1376f728019bSEric W. Biederman has_files = 1; 1377f728019bSEric W. Biederman } 1378f728019bSEric W. Biederman return nr_subheaders + has_files; 1379f728019bSEric W. Biederman } 1380f728019bSEric W. Biederman 1381f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 138260a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1383f728019bSEric W. Biederman struct ctl_table *table) 1384f728019bSEric W. Biederman { 1385f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1386f728019bSEric W. Biederman struct ctl_table *entry, *files; 1387f728019bSEric W. Biederman int nr_files = 0; 1388f728019bSEric W. Biederman int nr_dirs = 0; 1389f728019bSEric W. Biederman int err = -ENOMEM; 1390f728019bSEric W. Biederman 1391f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1392f728019bSEric W. Biederman if (entry->child) 1393f728019bSEric W. Biederman nr_dirs++; 1394f728019bSEric W. Biederman else 1395f728019bSEric W. Biederman nr_files++; 1396f728019bSEric W. Biederman } 1397f728019bSEric W. Biederman 1398f728019bSEric W. Biederman files = table; 1399f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1400f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1401f728019bSEric W. Biederman struct ctl_table *new; 1402f728019bSEric W. Biederman files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), 1403f728019bSEric W. Biederman GFP_KERNEL); 1404f728019bSEric W. Biederman if (!files) 1405f728019bSEric W. Biederman goto out; 1406f728019bSEric W. Biederman 1407f728019bSEric W. Biederman ctl_table_arg = files; 1408f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1409f728019bSEric W. Biederman if (entry->child) 1410f728019bSEric W. Biederman continue; 1411f728019bSEric W. Biederman *new = *entry; 1412f728019bSEric W. Biederman new++; 1413f728019bSEric W. Biederman } 1414f728019bSEric W. Biederman } 1415f728019bSEric W. Biederman 1416f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1417f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1418f728019bSEric W. Biederman struct ctl_table_header *header; 141960a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1420f728019bSEric W. Biederman if (!header) { 1421f728019bSEric W. Biederman kfree(ctl_table_arg); 1422f728019bSEric W. Biederman goto out; 1423f728019bSEric W. Biederman } 1424f728019bSEric W. Biederman 1425f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1426f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1427f728019bSEric W. Biederman **subheader = header; 1428f728019bSEric W. Biederman (*subheader)++; 1429f728019bSEric W. Biederman } 1430f728019bSEric W. Biederman 1431f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1432f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1433f728019bSEric W. Biederman char *child_pos; 1434f728019bSEric W. Biederman 1435f728019bSEric W. Biederman if (!entry->child) 1436f728019bSEric W. Biederman continue; 1437f728019bSEric W. Biederman 1438f728019bSEric W. Biederman err = -ENAMETOOLONG; 1439f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1440f728019bSEric W. Biederman if (!child_pos) 1441f728019bSEric W. Biederman goto out; 1442f728019bSEric W. Biederman 1443f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 144460a47a2eSEric W. Biederman set, entry->child); 1445f728019bSEric W. Biederman pos[0] = '\0'; 1446f728019bSEric W. Biederman if (err) 1447f728019bSEric W. Biederman goto out; 1448f728019bSEric W. Biederman } 1449f728019bSEric W. Biederman err = 0; 1450f728019bSEric W. Biederman out: 1451f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1452f728019bSEric W. Biederman return err; 1453f728019bSEric W. Biederman } 1454f728019bSEric W. Biederman 14556e9d5164SEric W. Biederman /** 14566e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 145760a47a2eSEric W. Biederman * @set: Sysctl tree to register on 14586e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14596e9d5164SEric W. Biederman * @table: the top-level table structure 14606e9d5164SEric W. Biederman * 14616e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14626e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14636e9d5164SEric W. Biederman * 14646e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 14656e9d5164SEric W. Biederman */ 14666e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 146760a47a2eSEric W. Biederman struct ctl_table_set *set, 14686e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 14696e9d5164SEric W. Biederman { 1470ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1471f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1472f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 14736e9d5164SEric W. Biederman const struct ctl_path *component; 14746e9d5164SEric W. Biederman char *new_path, *pos; 14756e9d5164SEric W. Biederman 14766e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 14776e9d5164SEric W. Biederman if (!new_path) 14786e9d5164SEric W. Biederman return NULL; 14796e9d5164SEric W. Biederman 14806e9d5164SEric W. Biederman pos[0] = '\0'; 14816e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 14826e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 14836e9d5164SEric W. Biederman if (!pos) 14846e9d5164SEric W. Biederman goto out; 14856e9d5164SEric W. Biederman } 1486ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1487ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1488ec6a5266SEric W. Biederman if (!pos) 1489ec6a5266SEric W. Biederman goto out; 1490ec6a5266SEric W. Biederman table = table->child; 1491ec6a5266SEric W. Biederman } 1492f728019bSEric W. Biederman if (nr_subheaders == 1) { 149360a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1494ec6a5266SEric W. Biederman if (header) 1495ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1496f728019bSEric W. Biederman } else { 1497f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1498f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1499f728019bSEric W. Biederman if (!header) 1500f728019bSEric W. Biederman goto out; 1501f728019bSEric W. Biederman 1502f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1503f728019bSEric W. Biederman subheader = subheaders; 1504f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1505f728019bSEric W. Biederman 1506f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 150760a47a2eSEric W. Biederman set, table)) 1508f728019bSEric W. Biederman goto err_register_leaves; 1509f728019bSEric W. Biederman } 1510f728019bSEric W. Biederman 15116e9d5164SEric W. Biederman out: 15126e9d5164SEric W. Biederman kfree(new_path); 15136e9d5164SEric W. Biederman return header; 1514f728019bSEric W. Biederman 1515f728019bSEric W. Biederman err_register_leaves: 1516f728019bSEric W. Biederman while (subheader > subheaders) { 1517f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1518f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1519f728019bSEric W. Biederman unregister_sysctl_table(subh); 1520f728019bSEric W. Biederman kfree(table); 1521f728019bSEric W. Biederman } 1522f728019bSEric W. Biederman kfree(header); 1523f728019bSEric W. Biederman header = NULL; 1524f728019bSEric W. Biederman goto out; 15256e9d5164SEric W. Biederman } 15266e9d5164SEric W. Biederman 15271f87f0b5SEric W. Biederman /** 15281f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 15291f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15301f87f0b5SEric W. Biederman * @table: the top-level table structure 15311f87f0b5SEric W. Biederman * 15321f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15331f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15341f87f0b5SEric W. Biederman * 15351f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 15361f87f0b5SEric W. Biederman */ 15371f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 15381f87f0b5SEric W. Biederman struct ctl_table *table) 15391f87f0b5SEric W. Biederman { 154060a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 15411f87f0b5SEric W. Biederman path, table); 15421f87f0b5SEric W. Biederman } 15431f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 15441f87f0b5SEric W. Biederman 15451f87f0b5SEric W. Biederman /** 15461f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 15471f87f0b5SEric W. Biederman * @table: the top-level table structure 15481f87f0b5SEric W. Biederman * 15491f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15501f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15511f87f0b5SEric W. Biederman * 15521f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 15531f87f0b5SEric W. Biederman */ 15541f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 15551f87f0b5SEric W. Biederman { 15561f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 15571f87f0b5SEric W. Biederman 15581f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 15591f87f0b5SEric W. Biederman } 15601f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 15611f87f0b5SEric W. Biederman 15620e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 15630e47c99dSEric W. Biederman { 15640e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 15650e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 15660e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 15670e47c99dSEric W. Biederman struct ctl_dir *core_parent; 15680e47c99dSEric W. Biederman struct ctl_table *entry; 15690e47c99dSEric W. Biederman 15700e47c99dSEric W. Biederman if (header->set == root_set) 15710e47c99dSEric W. Biederman return; 15720e47c99dSEric W. Biederman 15730e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 15740e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 15750e47c99dSEric W. Biederman return; 15760e47c99dSEric W. Biederman 15770e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 15780e47c99dSEric W. Biederman struct ctl_table_header *link_head; 15790e47c99dSEric W. Biederman struct ctl_table *link; 15800e47c99dSEric W. Biederman const char *name = entry->procname; 15810e47c99dSEric W. Biederman 15820e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 15830e47c99dSEric W. Biederman if (link && 15840e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 15850e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 15860e47c99dSEric W. Biederman drop_sysctl_table(link_head); 15870e47c99dSEric W. Biederman } 15880e47c99dSEric W. Biederman else { 158987ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 15900e47c99dSEric W. Biederman sysctl_print_dir(parent); 159187ebdc00SAndrew Morton pr_cont("/%s\n", name); 15920e47c99dSEric W. Biederman } 15930e47c99dSEric W. Biederman } 15940e47c99dSEric W. Biederman } 15950e47c99dSEric W. Biederman 1596938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1597938aaa4fSEric W. Biederman { 15987ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 15997ec66d06SEric W. Biederman 1600938aaa4fSEric W. Biederman if (--header->nreg) 1601938aaa4fSEric W. Biederman return; 1602938aaa4fSEric W. Biederman 16030e47c99dSEric W. Biederman put_links(header); 1604938aaa4fSEric W. Biederman start_unregistering(header); 1605938aaa4fSEric W. Biederman if (!--header->count) 1606938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16077ec66d06SEric W. Biederman 16087ec66d06SEric W. Biederman if (parent) 16097ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1610938aaa4fSEric W. Biederman } 1611938aaa4fSEric W. Biederman 16121f87f0b5SEric W. Biederman /** 16131f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16141f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16151f87f0b5SEric W. Biederman * 16161f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16171f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16181f87f0b5SEric W. Biederman */ 16191f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16201f87f0b5SEric W. Biederman { 1621f728019bSEric W. Biederman int nr_subheaders; 16221f87f0b5SEric W. Biederman might_sleep(); 16231f87f0b5SEric W. Biederman 16241f87f0b5SEric W. Biederman if (header == NULL) 16251f87f0b5SEric W. Biederman return; 16261f87f0b5SEric W. Biederman 1627f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1628f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1629f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1630f728019bSEric W. Biederman int i; 1631f728019bSEric W. Biederman 1632f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1633f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1634f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1635f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1636f728019bSEric W. Biederman unregister_sysctl_table(subh); 1637f728019bSEric W. Biederman kfree(table); 1638f728019bSEric W. Biederman } 1639f728019bSEric W. Biederman kfree(header); 1640f728019bSEric W. Biederman return; 1641f728019bSEric W. Biederman } 1642f728019bSEric W. Biederman 16431f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1644938aaa4fSEric W. Biederman drop_sysctl_table(header); 16451f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 16461f87f0b5SEric W. Biederman } 16471f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 16481f87f0b5SEric W. Biederman 16490e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 16509eb47c26SEric W. Biederman struct ctl_table_root *root, 16511f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 16521f87f0b5SEric W. Biederman { 16531347440dSDan Carpenter memset(set, 0, sizeof(*set)); 16540e47c99dSEric W. Biederman set->is_seen = is_seen; 1655ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 16561f87f0b5SEric W. Biederman } 16571f87f0b5SEric W. Biederman 165897324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 165997324cd8SEric W. Biederman { 1660ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 166197324cd8SEric W. Biederman } 16621f87f0b5SEric W. Biederman 16631e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 166477b14db5SEric W. Biederman { 1665e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1666e1675231SAlexey Dobriyan 166777b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 16689043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 16699043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 167077b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1671de4e83bdSEric W. Biederman 1672de4e83bdSEric W. Biederman return sysctl_init(); 167377b14db5SEric W. Biederman } 1674