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> 877b14db5SEric W. Biederman #include <linux/security.h> 934286d66SNick Piggin #include <linux/namei.h> 101f87f0b5SEric W. Biederman #include <linux/module.h> 1177b14db5SEric W. Biederman #include "internal.h" 1277b14db5SEric W. Biederman 13d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1477b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 1503a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 169043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 179043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 1877b14db5SEric W. Biederman 19f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 20f1ecf068SLucas De Marchi { 21f1ecf068SLucas De Marchi if (!poll) 22f1ecf068SLucas De Marchi return; 23f1ecf068SLucas De Marchi 24f1ecf068SLucas De Marchi atomic_inc(&poll->event); 25f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 26f1ecf068SLucas De Marchi } 27f1ecf068SLucas De Marchi 28a194558eSEric W. Biederman static struct ctl_table root_table[] = { 29a194558eSEric W. Biederman { 30a194558eSEric W. Biederman .procname = "", 31a194558eSEric W. Biederman .mode = S_IRUGO|S_IXUGO, 32a194558eSEric W. Biederman .child = &root_table[1], 33a194558eSEric W. Biederman }, 34a194558eSEric W. Biederman { } 35a194558eSEric W. Biederman }; 361f87f0b5SEric W. Biederman static struct ctl_table_root sysctl_table_root; 371f87f0b5SEric W. Biederman static struct ctl_table_header root_table_header = { 381f87f0b5SEric W. Biederman {{.count = 1, 39938aaa4fSEric W. Biederman .nreg = 1, 401f87f0b5SEric W. Biederman .ctl_table = root_table, 411f87f0b5SEric W. Biederman .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, 421f87f0b5SEric W. Biederman .root = &sysctl_table_root, 431f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 441f87f0b5SEric W. Biederman }; 451f87f0b5SEric W. Biederman static struct ctl_table_root sysctl_table_root = { 461f87f0b5SEric W. Biederman .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list), 471f87f0b5SEric W. Biederman .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry), 481f87f0b5SEric W. Biederman }; 491f87f0b5SEric W. Biederman 501f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 511f87f0b5SEric W. Biederman 52076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 53076c3eedSEric W. Biederman { 54076c3eedSEric W. Biederman int minlen; 55076c3eedSEric W. Biederman int cmp; 56076c3eedSEric W. Biederman 57076c3eedSEric W. Biederman minlen = len1; 58076c3eedSEric W. Biederman if (minlen > len2) 59076c3eedSEric W. Biederman minlen = len2; 60076c3eedSEric W. Biederman 61076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 62076c3eedSEric W. Biederman if (cmp == 0) 63076c3eedSEric W. Biederman cmp = len1 - len2; 64076c3eedSEric W. Biederman return cmp; 65076c3eedSEric W. Biederman } 66076c3eedSEric W. Biederman 67076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 68076c3eedSEric W. Biederman struct ctl_table_set *set, 69076c3eedSEric W. Biederman struct ctl_table_header *dir_head, struct ctl_table *dir, 70076c3eedSEric W. Biederman const char *name, int namelen) 71076c3eedSEric W. Biederman { 72076c3eedSEric W. Biederman struct ctl_table_header *head; 73076c3eedSEric W. Biederman struct ctl_table *entry; 74076c3eedSEric W. Biederman 75076c3eedSEric W. Biederman if (dir_head->set == set) { 76076c3eedSEric W. Biederman for (entry = dir; entry->procname; entry++) { 77076c3eedSEric W. Biederman const char *procname = entry->procname; 78076c3eedSEric W. Biederman if (namecmp(procname, strlen(procname), name, namelen) == 0) { 79076c3eedSEric W. Biederman *phead = dir_head; 80076c3eedSEric W. Biederman return entry; 81076c3eedSEric W. Biederman } 82076c3eedSEric W. Biederman } 83076c3eedSEric W. Biederman } 84076c3eedSEric W. Biederman 85076c3eedSEric W. Biederman list_for_each_entry(head, &set->list, ctl_entry) { 86076c3eedSEric W. Biederman if (head->unregistering) 87076c3eedSEric W. Biederman continue; 88076c3eedSEric W. Biederman if (head->attached_to != dir) 89076c3eedSEric W. Biederman continue; 90076c3eedSEric W. Biederman for (entry = head->attached_by; entry->procname; entry++) { 91076c3eedSEric W. Biederman const char *procname = entry->procname; 92076c3eedSEric W. Biederman if (namecmp(procname, strlen(procname), name, namelen) == 0) { 93076c3eedSEric W. Biederman *phead = head; 94076c3eedSEric W. Biederman return entry; 95076c3eedSEric W. Biederman } 96076c3eedSEric W. Biederman } 97076c3eedSEric W. Biederman } 98076c3eedSEric W. Biederman return NULL; 99076c3eedSEric W. Biederman } 100076c3eedSEric W. Biederman 101e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 102e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 103e0d04529SEric W. Biederman struct ctl_table *table) 104e0d04529SEric W. Biederman { 105e0d04529SEric W. Biederman head->ctl_table_arg = table; 106e0d04529SEric W. Biederman INIT_LIST_HEAD(&head->ctl_entry); 107e0d04529SEric W. Biederman head->used = 0; 108e0d04529SEric W. Biederman head->count = 1; 109e0d04529SEric W. Biederman head->nreg = 1; 110e0d04529SEric W. Biederman head->unregistering = NULL; 111e0d04529SEric W. Biederman head->root = root; 112e0d04529SEric W. Biederman head->set = set; 113e0d04529SEric W. Biederman head->parent = NULL; 114e0d04529SEric W. Biederman } 115e0d04529SEric W. Biederman 1168425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 1178425d6aaSEric W. Biederman { 1188425d6aaSEric W. Biederman list_del_init(&head->ctl_entry); 1198425d6aaSEric W. Biederman } 1208425d6aaSEric W. Biederman 1218425d6aaSEric W. Biederman static void insert_header(struct ctl_table_header *header) 1228425d6aaSEric W. Biederman { 1238425d6aaSEric W. Biederman header->parent->count++; 1248425d6aaSEric W. Biederman list_add_tail(&header->ctl_entry, &header->set->list); 1258425d6aaSEric W. Biederman } 1268425d6aaSEric W. Biederman 1271f87f0b5SEric W. Biederman /* called under sysctl_lock */ 1281f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 1291f87f0b5SEric W. Biederman { 1301f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 1311f87f0b5SEric W. Biederman return 0; 1321f87f0b5SEric W. Biederman p->used++; 1331f87f0b5SEric W. Biederman return 1; 1341f87f0b5SEric W. Biederman } 1351f87f0b5SEric W. Biederman 1361f87f0b5SEric W. Biederman /* called under sysctl_lock */ 1371f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 1381f87f0b5SEric W. Biederman { 1391f87f0b5SEric W. Biederman if (!--p->used) 1401f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 1411f87f0b5SEric W. Biederman complete(p->unregistering); 1421f87f0b5SEric W. Biederman } 1431f87f0b5SEric W. Biederman 1441f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 1451f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 1461f87f0b5SEric W. Biederman { 1471f87f0b5SEric W. Biederman /* 1481f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 1491f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 1501f87f0b5SEric W. Biederman */ 1511f87f0b5SEric W. Biederman if (unlikely(p->used)) { 1521f87f0b5SEric W. Biederman struct completion wait; 1531f87f0b5SEric W. Biederman init_completion(&wait); 1541f87f0b5SEric W. Biederman p->unregistering = &wait; 1551f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1561f87f0b5SEric W. Biederman wait_for_completion(&wait); 1571f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1581f87f0b5SEric W. Biederman } else { 1591f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 1601f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 1611f87f0b5SEric W. Biederman } 1621f87f0b5SEric W. Biederman /* 1631f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 1641f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 1651f87f0b5SEric W. Biederman */ 1668425d6aaSEric W. Biederman erase_header(p); 1671f87f0b5SEric W. Biederman } 1681f87f0b5SEric W. Biederman 1691f87f0b5SEric W. Biederman static void sysctl_head_get(struct ctl_table_header *head) 1701f87f0b5SEric W. Biederman { 1711f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1721f87f0b5SEric W. Biederman head->count++; 1731f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1741f87f0b5SEric W. Biederman } 1751f87f0b5SEric W. Biederman 1761f87f0b5SEric W. Biederman void sysctl_head_put(struct ctl_table_header *head) 1771f87f0b5SEric W. Biederman { 1781f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1791f87f0b5SEric W. Biederman if (!--head->count) 1801f87f0b5SEric W. Biederman kfree_rcu(head, rcu); 1811f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1821f87f0b5SEric W. Biederman } 1831f87f0b5SEric W. Biederman 1841f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 1851f87f0b5SEric W. Biederman { 1861f87f0b5SEric W. Biederman if (!head) 1871f87f0b5SEric W. Biederman BUG(); 1881f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1891f87f0b5SEric W. Biederman if (!use_table(head)) 1901f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 1911f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 1921f87f0b5SEric W. Biederman return head; 1931f87f0b5SEric W. Biederman } 1941f87f0b5SEric W. Biederman 1951f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 1961f87f0b5SEric W. Biederman { 1971f87f0b5SEric W. Biederman if (!head) 1981f87f0b5SEric W. Biederman return; 1991f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2001f87f0b5SEric W. Biederman unuse_table(head); 2011f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2021f87f0b5SEric W. Biederman } 2031f87f0b5SEric W. Biederman 2041f87f0b5SEric W. Biederman static struct ctl_table_set * 2051f87f0b5SEric W. Biederman lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) 2061f87f0b5SEric W. Biederman { 2071f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 2081f87f0b5SEric W. Biederman if (root->lookup) 2091f87f0b5SEric W. Biederman set = root->lookup(root, namespaces); 2101f87f0b5SEric W. Biederman return set; 2111f87f0b5SEric W. Biederman } 2121f87f0b5SEric W. Biederman 2131f87f0b5SEric W. Biederman static struct list_head * 2141f87f0b5SEric W. Biederman lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces) 2151f87f0b5SEric W. Biederman { 2161f87f0b5SEric W. Biederman struct ctl_table_set *set = lookup_header_set(root, namespaces); 2171f87f0b5SEric W. Biederman return &set->list; 2181f87f0b5SEric W. Biederman } 2191f87f0b5SEric W. Biederman 220076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 221076c3eedSEric W. Biederman struct ctl_table_header *dir_head, 222076c3eedSEric W. Biederman struct ctl_table *dir, 223076c3eedSEric W. Biederman const char *name, int namelen) 224076c3eedSEric W. Biederman { 225076c3eedSEric W. Biederman struct ctl_table_header *head; 226076c3eedSEric W. Biederman struct ctl_table *entry; 227076c3eedSEric W. Biederman struct ctl_table_root *root; 228076c3eedSEric W. Biederman struct ctl_table_set *set; 229076c3eedSEric W. Biederman 230076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 231076c3eedSEric W. Biederman root = &sysctl_table_root; 232076c3eedSEric W. Biederman do { 233076c3eedSEric W. Biederman set = lookup_header_set(root, current->nsproxy); 234076c3eedSEric W. Biederman entry = find_entry(&head, set, dir_head, dir, name, namelen); 235076c3eedSEric W. Biederman if (entry && use_table(head)) 236076c3eedSEric W. Biederman *phead = head; 237076c3eedSEric W. Biederman else 238076c3eedSEric W. Biederman entry = NULL; 239076c3eedSEric W. Biederman root = list_entry(root->root_list.next, 240076c3eedSEric W. Biederman struct ctl_table_root, root_list); 241076c3eedSEric W. Biederman } while (!entry && root != &sysctl_table_root); 242076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 243076c3eedSEric W. Biederman return entry; 244076c3eedSEric W. Biederman } 245076c3eedSEric W. Biederman 2461f87f0b5SEric W. Biederman static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces, 2471f87f0b5SEric W. Biederman struct ctl_table_header *prev) 2481f87f0b5SEric W. Biederman { 2491f87f0b5SEric W. Biederman struct ctl_table_root *root; 2501f87f0b5SEric W. Biederman struct list_head *header_list; 2511f87f0b5SEric W. Biederman struct ctl_table_header *head; 2521f87f0b5SEric W. Biederman struct list_head *tmp; 2531f87f0b5SEric W. Biederman 2541f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2551f87f0b5SEric W. Biederman if (prev) { 2561f87f0b5SEric W. Biederman head = prev; 2571f87f0b5SEric W. Biederman tmp = &prev->ctl_entry; 2581f87f0b5SEric W. Biederman unuse_table(prev); 2591f87f0b5SEric W. Biederman goto next; 2601f87f0b5SEric W. Biederman } 2611f87f0b5SEric W. Biederman tmp = &root_table_header.ctl_entry; 2621f87f0b5SEric W. Biederman for (;;) { 2631f87f0b5SEric W. Biederman head = list_entry(tmp, struct ctl_table_header, ctl_entry); 2641f87f0b5SEric W. Biederman 2651f87f0b5SEric W. Biederman if (!use_table(head)) 2661f87f0b5SEric W. Biederman goto next; 2671f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2681f87f0b5SEric W. Biederman return head; 2691f87f0b5SEric W. Biederman next: 2701f87f0b5SEric W. Biederman root = head->root; 2711f87f0b5SEric W. Biederman tmp = tmp->next; 2721f87f0b5SEric W. Biederman header_list = lookup_header_list(root, namespaces); 2731f87f0b5SEric W. Biederman if (tmp != header_list) 2741f87f0b5SEric W. Biederman continue; 2751f87f0b5SEric W. Biederman 2761f87f0b5SEric W. Biederman do { 2771f87f0b5SEric W. Biederman root = list_entry(root->root_list.next, 2781f87f0b5SEric W. Biederman struct ctl_table_root, root_list); 2791f87f0b5SEric W. Biederman if (root == &sysctl_table_root) 2801f87f0b5SEric W. Biederman goto out; 2811f87f0b5SEric W. Biederman header_list = lookup_header_list(root, namespaces); 2821f87f0b5SEric W. Biederman } while (list_empty(header_list)); 2831f87f0b5SEric W. Biederman tmp = header_list->next; 2841f87f0b5SEric W. Biederman } 2851f87f0b5SEric W. Biederman out: 2861f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2871f87f0b5SEric W. Biederman return NULL; 2881f87f0b5SEric W. Biederman } 2891f87f0b5SEric W. Biederman 2901f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev) 2911f87f0b5SEric W. Biederman { 2921f87f0b5SEric W. Biederman return __sysctl_head_next(current->nsproxy, prev); 2931f87f0b5SEric W. Biederman } 2941f87f0b5SEric W. Biederman 2951f87f0b5SEric W. Biederman void register_sysctl_root(struct ctl_table_root *root) 2961f87f0b5SEric W. Biederman { 2971f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2981f87f0b5SEric W. Biederman list_add_tail(&root->root_list, &sysctl_table_root.root_list); 2991f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3001f87f0b5SEric W. Biederman } 3011f87f0b5SEric W. Biederman 3021f87f0b5SEric W. Biederman /* 3031f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 3041f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 3051f87f0b5SEric W. Biederman */ 3061f87f0b5SEric W. Biederman 3071f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 3081f87f0b5SEric W. Biederman { 3091f87f0b5SEric W. Biederman if (!current_euid()) 3101f87f0b5SEric W. Biederman mode >>= 6; 3111f87f0b5SEric W. Biederman else if (in_egroup_p(0)) 3121f87f0b5SEric W. Biederman mode >>= 3; 3131f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 3141f87f0b5SEric W. Biederman return 0; 3151f87f0b5SEric W. Biederman return -EACCES; 3161f87f0b5SEric W. Biederman } 3171f87f0b5SEric W. Biederman 3181f87f0b5SEric W. Biederman static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op) 3191f87f0b5SEric W. Biederman { 3201f87f0b5SEric W. Biederman int mode; 3211f87f0b5SEric W. Biederman 3221f87f0b5SEric W. Biederman if (root->permissions) 3231f87f0b5SEric W. Biederman mode = root->permissions(root, current->nsproxy, table); 3241f87f0b5SEric W. Biederman else 3251f87f0b5SEric W. Biederman mode = table->mode; 3261f87f0b5SEric W. Biederman 3271f87f0b5SEric W. Biederman return test_perm(mode, op); 3281f87f0b5SEric W. Biederman } 3291f87f0b5SEric W. Biederman 3309043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 3319043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 33277b14db5SEric W. Biederman { 33377b14db5SEric W. Biederman struct inode *inode; 3349043476fSAl Viro struct proc_inode *ei; 33577b14db5SEric W. Biederman 3369043476fSAl Viro inode = new_inode(sb); 33777b14db5SEric W. Biederman if (!inode) 33877b14db5SEric W. Biederman goto out; 33977b14db5SEric W. Biederman 34085fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 34185fe4025SChristoph Hellwig 3429043476fSAl Viro sysctl_head_get(head); 34377b14db5SEric W. Biederman ei = PROC_I(inode); 3449043476fSAl Viro ei->sysctl = head; 3459043476fSAl Viro ei->sysctl_entry = table; 3469043476fSAl Viro 34777b14db5SEric W. Biederman inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 3489043476fSAl Viro inode->i_mode = table->mode; 3499043476fSAl Viro if (!table->child) { 3509043476fSAl Viro inode->i_mode |= S_IFREG; 35177b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 35277b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 3539043476fSAl Viro } else { 3549043476fSAl Viro inode->i_mode |= S_IFDIR; 3559043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 3569043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 3579043476fSAl Viro } 35877b14db5SEric W. Biederman out: 35977b14db5SEric W. Biederman return inode; 36077b14db5SEric W. Biederman } 36177b14db5SEric W. Biederman 36281324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 36377b14db5SEric W. Biederman { 3643cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 3653cc3e046SEric W. Biederman if (!head) 3663cc3e046SEric W. Biederman head = &root_table_header; 3673cc3e046SEric W. Biederman return sysctl_head_grab(head); 36877b14db5SEric W. Biederman } 36977b14db5SEric W. Biederman 37077b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 37177b14db5SEric W. Biederman struct nameidata *nd) 37277b14db5SEric W. Biederman { 3739043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 3749043476fSAl Viro struct ctl_table *table = PROC_I(dir)->sysctl_entry; 3759043476fSAl Viro struct ctl_table_header *h = NULL; 3769043476fSAl Viro struct qstr *name = &dentry->d_name; 3779043476fSAl Viro struct ctl_table *p; 37877b14db5SEric W. Biederman struct inode *inode; 3799043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 38077b14db5SEric W. Biederman 3819043476fSAl Viro if (IS_ERR(head)) 3829043476fSAl Viro return ERR_CAST(head); 3839043476fSAl Viro 3849043476fSAl Viro if (table && !table->child) { 3859043476fSAl Viro WARN_ON(1); 3869043476fSAl Viro goto out; 3879043476fSAl Viro } 3889043476fSAl Viro 389a194558eSEric W. Biederman table = table ? table->child : &head->ctl_table[1]; 3909043476fSAl Viro 391076c3eedSEric W. Biederman p = lookup_entry(&h, head, table, name->name, name->len); 3929043476fSAl Viro if (!p) 39377b14db5SEric W. Biederman goto out; 39477b14db5SEric W. Biederman 39577b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 3969043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 3979043476fSAl Viro if (h) 3989043476fSAl Viro sysctl_head_finish(h); 3999043476fSAl Viro 40077b14db5SEric W. Biederman if (!inode) 40177b14db5SEric W. Biederman goto out; 40277b14db5SEric W. Biederman 40377b14db5SEric W. Biederman err = NULL; 404fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 40577b14db5SEric W. Biederman d_add(dentry, inode); 40677b14db5SEric W. Biederman 40777b14db5SEric W. Biederman out: 40877b14db5SEric W. Biederman sysctl_head_finish(head); 40977b14db5SEric W. Biederman return err; 41077b14db5SEric W. Biederman } 41177b14db5SEric W. Biederman 4127708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 4137708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 41477b14db5SEric W. Biederman { 4159043476fSAl Viro struct inode *inode = filp->f_path.dentry->d_inode; 4169043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 4179043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 4182a2da53bSDavid Howells ssize_t error; 4192a2da53bSDavid Howells size_t res; 42077b14db5SEric W. Biederman 4219043476fSAl Viro if (IS_ERR(head)) 4229043476fSAl Viro return PTR_ERR(head); 42377b14db5SEric W. Biederman 42477b14db5SEric W. Biederman /* 42577b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 42677b14db5SEric W. Biederman * and won't be until we finish. 42777b14db5SEric W. Biederman */ 42877b14db5SEric W. Biederman error = -EPERM; 429d7321cd6SPavel Emelyanov if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) 43077b14db5SEric W. Biederman goto out; 43177b14db5SEric W. Biederman 4329043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 4339043476fSAl Viro error = -EINVAL; 4349043476fSAl Viro if (!table->proc_handler) 4359043476fSAl Viro goto out; 4369043476fSAl Viro 43777b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 43877b14db5SEric W. Biederman res = count; 4398d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 44077b14db5SEric W. Biederman if (!error) 44177b14db5SEric W. Biederman error = res; 44277b14db5SEric W. Biederman out: 44377b14db5SEric W. Biederman sysctl_head_finish(head); 44477b14db5SEric W. Biederman 44577b14db5SEric W. Biederman return error; 44677b14db5SEric W. Biederman } 44777b14db5SEric W. Biederman 4487708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 4497708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 4507708bfb1SPavel Emelyanov { 4517708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 4527708bfb1SPavel Emelyanov } 4537708bfb1SPavel Emelyanov 45477b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 45577b14db5SEric W. Biederman size_t count, loff_t *ppos) 45677b14db5SEric W. Biederman { 4577708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 45877b14db5SEric W. Biederman } 45977b14db5SEric W. Biederman 460f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 461f1ecf068SLucas De Marchi { 462f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 463f1ecf068SLucas De Marchi 464f1ecf068SLucas De Marchi if (table->poll) 465f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 466f1ecf068SLucas De Marchi 467f1ecf068SLucas De Marchi return 0; 468f1ecf068SLucas De Marchi } 469f1ecf068SLucas De Marchi 470f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 471f1ecf068SLucas De Marchi { 472f1ecf068SLucas De Marchi struct inode *inode = filp->f_path.dentry->d_inode; 473f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 474f1ecf068SLucas De Marchi unsigned long event = (unsigned long)filp->private_data; 475f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 476f1ecf068SLucas De Marchi 477f1ecf068SLucas De Marchi if (!table->proc_handler) 478f1ecf068SLucas De Marchi goto out; 479f1ecf068SLucas De Marchi 480f1ecf068SLucas De Marchi if (!table->poll) 481f1ecf068SLucas De Marchi goto out; 482f1ecf068SLucas De Marchi 483f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 484f1ecf068SLucas De Marchi 485f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 486f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 487f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 488f1ecf068SLucas De Marchi } 489f1ecf068SLucas De Marchi 490f1ecf068SLucas De Marchi out: 491f1ecf068SLucas De Marchi return ret; 492f1ecf068SLucas De Marchi } 49377b14db5SEric W. Biederman 49477b14db5SEric W. Biederman static int proc_sys_fill_cache(struct file *filp, void *dirent, 4959043476fSAl Viro filldir_t filldir, 4969043476fSAl Viro struct ctl_table_header *head, 4979043476fSAl Viro struct ctl_table *table) 49877b14db5SEric W. Biederman { 49977b14db5SEric W. Biederman struct dentry *child, *dir = filp->f_path.dentry; 50077b14db5SEric W. Biederman struct inode *inode; 50177b14db5SEric W. Biederman struct qstr qname; 50277b14db5SEric W. Biederman ino_t ino = 0; 50377b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 50477b14db5SEric W. Biederman 50577b14db5SEric W. Biederman qname.name = table->procname; 50677b14db5SEric W. Biederman qname.len = strlen(table->procname); 50777b14db5SEric W. Biederman qname.hash = full_name_hash(qname.name, qname.len); 50877b14db5SEric W. Biederman 50977b14db5SEric W. Biederman child = d_lookup(dir, &qname); 51077b14db5SEric W. Biederman if (!child) { 5119043476fSAl Viro child = d_alloc(dir, &qname); 5129043476fSAl Viro if (child) { 5139043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 5149043476fSAl Viro if (!inode) { 5159043476fSAl Viro dput(child); 5169043476fSAl Viro return -ENOMEM; 5179043476fSAl Viro } else { 518fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 5199043476fSAl Viro d_add(child, inode); 52077b14db5SEric W. Biederman } 5219043476fSAl Viro } else { 5229043476fSAl Viro return -ENOMEM; 52377b14db5SEric W. Biederman } 52477b14db5SEric W. Biederman } 52577b14db5SEric W. Biederman inode = child->d_inode; 52677b14db5SEric W. Biederman ino = inode->i_ino; 52777b14db5SEric W. Biederman type = inode->i_mode >> 12; 52877b14db5SEric W. Biederman dput(child); 5299043476fSAl Viro return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); 5309043476fSAl Viro } 5319043476fSAl Viro 5329043476fSAl Viro static int scan(struct ctl_table_header *head, ctl_table *table, 5339043476fSAl Viro unsigned long *pos, struct file *file, 5349043476fSAl Viro void *dirent, filldir_t filldir) 5359043476fSAl Viro { 5369043476fSAl Viro 5372315ffa0SEric W. Biederman for (; table->procname; table++, (*pos)++) { 5389043476fSAl Viro int res; 5399043476fSAl Viro 5409043476fSAl Viro if (*pos < file->f_pos) 5419043476fSAl Viro continue; 5429043476fSAl Viro 5439043476fSAl Viro res = proc_sys_fill_cache(file, dirent, filldir, head, table); 5449043476fSAl Viro if (res) 5459043476fSAl Viro return res; 5469043476fSAl Viro 5479043476fSAl Viro file->f_pos = *pos + 1; 5489043476fSAl Viro } 5499043476fSAl Viro return 0; 55077b14db5SEric W. Biederman } 55177b14db5SEric W. Biederman 55277b14db5SEric W. Biederman static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) 55377b14db5SEric W. Biederman { 5549043476fSAl Viro struct dentry *dentry = filp->f_path.dentry; 55577b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 5569043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5579043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5589043476fSAl Viro struct ctl_table_header *h = NULL; 55977b14db5SEric W. Biederman unsigned long pos; 5609043476fSAl Viro int ret = -EINVAL; 56177b14db5SEric W. Biederman 5629043476fSAl Viro if (IS_ERR(head)) 5639043476fSAl Viro return PTR_ERR(head); 5649043476fSAl Viro 5659043476fSAl Viro if (table && !table->child) { 5669043476fSAl Viro WARN_ON(1); 56777b14db5SEric W. Biederman goto out; 5689043476fSAl Viro } 5699043476fSAl Viro 570a194558eSEric W. Biederman table = table ? table->child : &head->ctl_table[1]; 57177b14db5SEric W. Biederman 57277b14db5SEric W. Biederman ret = 0; 57377b14db5SEric W. Biederman /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ 57477b14db5SEric W. Biederman if (filp->f_pos == 0) { 57577b14db5SEric W. Biederman if (filldir(dirent, ".", 1, filp->f_pos, 57677b14db5SEric W. Biederman inode->i_ino, DT_DIR) < 0) 57777b14db5SEric W. Biederman goto out; 57877b14db5SEric W. Biederman filp->f_pos++; 57977b14db5SEric W. Biederman } 58077b14db5SEric W. Biederman if (filp->f_pos == 1) { 58177b14db5SEric W. Biederman if (filldir(dirent, "..", 2, filp->f_pos, 58277b14db5SEric W. Biederman parent_ino(dentry), DT_DIR) < 0) 58377b14db5SEric W. Biederman goto out; 58477b14db5SEric W. Biederman filp->f_pos++; 58577b14db5SEric W. Biederman } 58677b14db5SEric W. Biederman pos = 2; 58777b14db5SEric W. Biederman 5889043476fSAl Viro ret = scan(head, table, &pos, filp, dirent, filldir); 5899043476fSAl Viro if (ret) 59077b14db5SEric W. Biederman goto out; 5919043476fSAl Viro 5929043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 5939043476fSAl Viro if (h->attached_to != table) 5949043476fSAl Viro continue; 5959043476fSAl Viro ret = scan(h, h->attached_by, &pos, filp, dirent, filldir); 5969043476fSAl Viro if (ret) { 5979043476fSAl Viro sysctl_head_finish(h); 5989043476fSAl Viro break; 59977b14db5SEric W. Biederman } 60077b14db5SEric W. Biederman } 60177b14db5SEric W. Biederman ret = 1; 60277b14db5SEric W. Biederman out: 60377b14db5SEric W. Biederman sysctl_head_finish(head); 60477b14db5SEric W. Biederman return ret; 60577b14db5SEric W. Biederman } 60677b14db5SEric W. Biederman 60710556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 60877b14db5SEric W. Biederman { 60977b14db5SEric W. Biederman /* 61077b14db5SEric W. Biederman * sysctl entries that are not writeable, 61177b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 61277b14db5SEric W. Biederman */ 613f696a365SMiklos Szeredi struct ctl_table_header *head; 614f696a365SMiklos Szeredi struct ctl_table *table; 61577b14db5SEric W. Biederman int error; 61677b14db5SEric W. Biederman 617f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 618f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 619f696a365SMiklos Szeredi return -EACCES; 620f696a365SMiklos Szeredi 621f696a365SMiklos Szeredi head = grab_header(inode); 6229043476fSAl Viro if (IS_ERR(head)) 6239043476fSAl Viro return PTR_ERR(head); 62477b14db5SEric W. Biederman 625f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 6269043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 6279043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 6289043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 6291fc0f78cSAl Viro error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK); 6309043476fSAl Viro 63177b14db5SEric W. Biederman sysctl_head_finish(head); 63277b14db5SEric W. Biederman return error; 63377b14db5SEric W. Biederman } 63477b14db5SEric W. Biederman 63577b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 63677b14db5SEric W. Biederman { 63777b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 63877b14db5SEric W. Biederman int error; 63977b14db5SEric W. Biederman 64077b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 64177b14db5SEric W. Biederman return -EPERM; 64277b14db5SEric W. Biederman 64377b14db5SEric W. Biederman error = inode_change_ok(inode, attr); 6441025774cSChristoph Hellwig if (error) 64577b14db5SEric W. Biederman return error; 6461025774cSChristoph Hellwig 6471025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 6481025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 6491025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 6501025774cSChristoph Hellwig if (error) 6511025774cSChristoph Hellwig return error; 6521025774cSChristoph Hellwig } 6531025774cSChristoph Hellwig 6541025774cSChristoph Hellwig setattr_copy(inode, attr); 6551025774cSChristoph Hellwig mark_inode_dirty(inode); 6561025774cSChristoph Hellwig return 0; 65777b14db5SEric W. Biederman } 65877b14db5SEric W. Biederman 6599043476fSAl Viro static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 6609043476fSAl Viro { 6619043476fSAl Viro struct inode *inode = dentry->d_inode; 6629043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 6639043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 6649043476fSAl Viro 6659043476fSAl Viro if (IS_ERR(head)) 6669043476fSAl Viro return PTR_ERR(head); 6679043476fSAl Viro 6689043476fSAl Viro generic_fillattr(inode, stat); 6699043476fSAl Viro if (table) 6709043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 6719043476fSAl Viro 6729043476fSAl Viro sysctl_head_finish(head); 6739043476fSAl Viro return 0; 6749043476fSAl Viro } 6759043476fSAl Viro 67677b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 677f1ecf068SLucas De Marchi .open = proc_sys_open, 678f1ecf068SLucas De Marchi .poll = proc_sys_poll, 67977b14db5SEric W. Biederman .read = proc_sys_read, 68077b14db5SEric W. Biederman .write = proc_sys_write, 6816038f373SArnd Bergmann .llseek = default_llseek, 6829043476fSAl Viro }; 6839043476fSAl Viro 6849043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 685887df078SPavel Emelyanov .read = generic_read_dir, 68677b14db5SEric W. Biederman .readdir = proc_sys_readdir, 6873222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 68877b14db5SEric W. Biederman }; 68977b14db5SEric W. Biederman 69003a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 6919043476fSAl Viro .permission = proc_sys_permission, 6929043476fSAl Viro .setattr = proc_sys_setattr, 6939043476fSAl Viro .getattr = proc_sys_getattr, 6949043476fSAl Viro }; 6959043476fSAl Viro 6969043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 69777b14db5SEric W. Biederman .lookup = proc_sys_lookup, 69877b14db5SEric W. Biederman .permission = proc_sys_permission, 69977b14db5SEric W. Biederman .setattr = proc_sys_setattr, 7009043476fSAl Viro .getattr = proc_sys_getattr, 70177b14db5SEric W. Biederman }; 70277b14db5SEric W. Biederman 70377b14db5SEric W. Biederman static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) 70477b14db5SEric W. Biederman { 70534286d66SNick Piggin if (nd->flags & LOOKUP_RCU) 70634286d66SNick Piggin return -ECHILD; 7079043476fSAl Viro return !PROC_I(dentry->d_inode)->sysctl->unregistering; 7089043476fSAl Viro } 7099043476fSAl Viro 710fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 7119043476fSAl Viro { 7129043476fSAl Viro return !!PROC_I(dentry->d_inode)->sysctl->unregistering; 7139043476fSAl Viro } 7149043476fSAl Viro 7151f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 7161f87f0b5SEric W. Biederman { 7171f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 7181f87f0b5SEric W. Biederman int res; 7191f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 7201f87f0b5SEric W. Biederman if (p->unregistering) 7211f87f0b5SEric W. Biederman res = 0; 7221f87f0b5SEric W. Biederman else if (!set->is_seen) 7231f87f0b5SEric W. Biederman res = 1; 7241f87f0b5SEric W. Biederman else 7251f87f0b5SEric W. Biederman res = set->is_seen(set); 7261f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 7271f87f0b5SEric W. Biederman return res; 7281f87f0b5SEric W. Biederman } 7291f87f0b5SEric W. Biederman 730621e155aSNick Piggin static int proc_sys_compare(const struct dentry *parent, 731621e155aSNick Piggin const struct inode *pinode, 732621e155aSNick Piggin const struct dentry *dentry, const struct inode *inode, 733621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 7349043476fSAl Viro { 735dfef6dcdSAl Viro struct ctl_table_header *head; 73631e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 73731e6b01fSNick Piggin * that inode here can be NULL */ 738dfef6dcdSAl Viro /* AV: can it, indeed? */ 73931e6b01fSNick Piggin if (!inode) 740dfef6dcdSAl Viro return 1; 741621e155aSNick Piggin if (name->len != len) 7429043476fSAl Viro return 1; 743621e155aSNick Piggin if (memcmp(name->name, str, len)) 7449043476fSAl Viro return 1; 745dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 746dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 74777b14db5SEric W. Biederman } 74877b14db5SEric W. Biederman 749d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 75077b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 7519043476fSAl Viro .d_delete = proc_sys_delete, 7529043476fSAl Viro .d_compare = proc_sys_compare, 75377b14db5SEric W. Biederman }; 75477b14db5SEric W. Biederman 7551f87f0b5SEric W. Biederman static struct ctl_table *is_branch_in(struct ctl_table *branch, 7561f87f0b5SEric W. Biederman struct ctl_table *table) 7571f87f0b5SEric W. Biederman { 7581f87f0b5SEric W. Biederman struct ctl_table *p; 7591f87f0b5SEric W. Biederman const char *s = branch->procname; 7601f87f0b5SEric W. Biederman 7611f87f0b5SEric W. Biederman /* branch should have named subdirectory as its first element */ 7621f87f0b5SEric W. Biederman if (!s || !branch->child) 7631f87f0b5SEric W. Biederman return NULL; 7641f87f0b5SEric W. Biederman 7651f87f0b5SEric W. Biederman /* ... and nothing else */ 7661f87f0b5SEric W. Biederman if (branch[1].procname) 7671f87f0b5SEric W. Biederman return NULL; 7681f87f0b5SEric W. Biederman 7691f87f0b5SEric W. Biederman /* table should contain subdirectory with the same name */ 7701f87f0b5SEric W. Biederman for (p = table; p->procname; p++) { 7711f87f0b5SEric W. Biederman if (!p->child) 7721f87f0b5SEric W. Biederman continue; 7731f87f0b5SEric W. Biederman if (p->procname && strcmp(p->procname, s) == 0) 7741f87f0b5SEric W. Biederman return p; 7751f87f0b5SEric W. Biederman } 7761f87f0b5SEric W. Biederman return NULL; 7771f87f0b5SEric W. Biederman } 7781f87f0b5SEric W. Biederman 7791f87f0b5SEric W. Biederman /* see if attaching q to p would be an improvement */ 7801f87f0b5SEric W. Biederman static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q) 7811f87f0b5SEric W. Biederman { 7821f87f0b5SEric W. Biederman struct ctl_table *to = p->ctl_table, *by = q->ctl_table; 7831f87f0b5SEric W. Biederman struct ctl_table *next; 7841f87f0b5SEric W. Biederman int is_better = 0; 7851f87f0b5SEric W. Biederman int not_in_parent = !p->attached_by; 7861f87f0b5SEric W. Biederman 7871f87f0b5SEric W. Biederman while ((next = is_branch_in(by, to)) != NULL) { 7881f87f0b5SEric W. Biederman if (by == q->attached_by) 7891f87f0b5SEric W. Biederman is_better = 1; 7901f87f0b5SEric W. Biederman if (to == p->attached_by) 7911f87f0b5SEric W. Biederman not_in_parent = 1; 7921f87f0b5SEric W. Biederman by = by->child; 7931f87f0b5SEric W. Biederman to = next->child; 7941f87f0b5SEric W. Biederman } 7951f87f0b5SEric W. Biederman 7961f87f0b5SEric W. Biederman if (is_better && not_in_parent) { 7971f87f0b5SEric W. Biederman q->attached_by = by; 7981f87f0b5SEric W. Biederman q->attached_to = to; 7991f87f0b5SEric W. Biederman q->parent = p; 8001f87f0b5SEric W. Biederman } 8011f87f0b5SEric W. Biederman } 8021f87f0b5SEric W. Biederman 8037c60c48fSEric W. Biederman static int sysctl_check_table_dups(const char *path, struct ctl_table *old, 8041f87f0b5SEric W. Biederman struct ctl_table *table) 8051f87f0b5SEric W. Biederman { 8067c60c48fSEric W. Biederman struct ctl_table *entry, *test; 8071f87f0b5SEric W. Biederman int error = 0; 8081f87f0b5SEric W. Biederman 8097c60c48fSEric W. Biederman for (entry = old; entry->procname; entry++) { 8107c60c48fSEric W. Biederman for (test = table; test->procname; test++) { 8117c60c48fSEric W. Biederman if (strcmp(entry->procname, test->procname) == 0) { 8127c60c48fSEric W. Biederman printk(KERN_ERR "sysctl duplicate entry: %s/%s\n", 8137c60c48fSEric W. Biederman path, test->procname); 8147c60c48fSEric W. Biederman error = -EEXIST; 8151f87f0b5SEric W. Biederman } 8167c60c48fSEric W. Biederman } 8177c60c48fSEric W. Biederman } 8187c60c48fSEric W. Biederman return error; 8197c60c48fSEric W. Biederman } 8207c60c48fSEric W. Biederman 8217c60c48fSEric W. Biederman static int sysctl_check_dups(struct nsproxy *namespaces, 8227c60c48fSEric W. Biederman struct ctl_table_header *header, 8237c60c48fSEric W. Biederman const char *path, struct ctl_table *table) 8247c60c48fSEric W. Biederman { 8257c60c48fSEric W. Biederman struct ctl_table_root *root; 8267c60c48fSEric W. Biederman struct ctl_table_set *set; 8277c60c48fSEric W. Biederman struct ctl_table_header *dir_head, *head; 8287c60c48fSEric W. Biederman struct ctl_table *dir_table; 8297c60c48fSEric W. Biederman int error = 0; 8307c60c48fSEric W. Biederman 8317c60c48fSEric W. Biederman /* No dups if we are the only member of our directory */ 8327c60c48fSEric W. Biederman if (header->attached_by != table) 8337c60c48fSEric W. Biederman return 0; 8347c60c48fSEric W. Biederman 8357c60c48fSEric W. Biederman dir_head = header->parent; 8367c60c48fSEric W. Biederman dir_table = header->attached_to; 8377c60c48fSEric W. Biederman 8387c60c48fSEric W. Biederman error = sysctl_check_table_dups(path, dir_table, table); 8397c60c48fSEric W. Biederman 8407c60c48fSEric W. Biederman root = &sysctl_table_root; 8417c60c48fSEric W. Biederman do { 8427c60c48fSEric W. Biederman set = lookup_header_set(root, namespaces); 8437c60c48fSEric W. Biederman 8447c60c48fSEric W. Biederman list_for_each_entry(head, &set->list, ctl_entry) { 8457c60c48fSEric W. Biederman if (head->unregistering) 8467c60c48fSEric W. Biederman continue; 8477c60c48fSEric W. Biederman if (head->attached_to != dir_table) 8487c60c48fSEric W. Biederman continue; 8497c60c48fSEric W. Biederman error = sysctl_check_table_dups(path, head->attached_by, 8507c60c48fSEric W. Biederman table); 8517c60c48fSEric W. Biederman } 8527c60c48fSEric W. Biederman root = list_entry(root->root_list.next, 8537c60c48fSEric W. Biederman struct ctl_table_root, root_list); 8547c60c48fSEric W. Biederman } while (root != &sysctl_table_root); 8557c60c48fSEric W. Biederman return error; 8567c60c48fSEric W. Biederman } 8577c60c48fSEric W. Biederman 8587c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 8597c60c48fSEric W. Biederman { 8607c60c48fSEric W. Biederman struct va_format vaf; 8617c60c48fSEric W. Biederman va_list args; 8627c60c48fSEric W. Biederman 8637c60c48fSEric W. Biederman va_start(args, fmt); 8647c60c48fSEric W. Biederman vaf.fmt = fmt; 8657c60c48fSEric W. Biederman vaf.va = &args; 8667c60c48fSEric W. Biederman 8677c60c48fSEric W. Biederman printk(KERN_ERR "sysctl table check failed: %s/%s %pV\n", 8687c60c48fSEric W. Biederman path, table->procname, &vaf); 8697c60c48fSEric W. Biederman 8707c60c48fSEric W. Biederman va_end(args); 8717c60c48fSEric W. Biederman return -EINVAL; 8727c60c48fSEric W. Biederman } 8737c60c48fSEric W. Biederman 8747c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 8757c60c48fSEric W. Biederman { 8767c60c48fSEric W. Biederman int err = 0; 8777c60c48fSEric W. Biederman for (; table->procname; table++) { 8787c60c48fSEric W. Biederman if (table->child) 8797c60c48fSEric W. Biederman err = sysctl_err(path, table, "Not a file"); 8807c60c48fSEric W. Biederman 8811f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 8821f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 8831f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 8841f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 8851f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 8861f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 8871f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 8881f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 8891f87f0b5SEric W. Biederman if (!table->data) 8907c60c48fSEric W. Biederman err = sysctl_err(path, table, "No data"); 8911f87f0b5SEric W. Biederman if (!table->maxlen) 8927c60c48fSEric W. Biederman err = sysctl_err(path, table, "No maxlen"); 8931f87f0b5SEric W. Biederman } 8941f87f0b5SEric W. Biederman if (!table->proc_handler) 8957c60c48fSEric W. Biederman err = sysctl_err(path, table, "No proc_handler"); 8967c60c48fSEric W. Biederman 8977c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 8987c60c48fSEric W. Biederman err = sysctl_err(path, table, "bogus .mode 0%o", 8997c60c48fSEric W. Biederman table->mode); 9001f87f0b5SEric W. Biederman } 9017c60c48fSEric W. Biederman return err; 9021f87f0b5SEric W. Biederman } 9031f87f0b5SEric W. Biederman 9041f87f0b5SEric W. Biederman /** 905f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 9061f87f0b5SEric W. Biederman * @root: List of sysctl headers to register on 9071f87f0b5SEric W. Biederman * @namespaces: Data to compute which lists of sysctl entries are visible 9081f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 9091f87f0b5SEric W. Biederman * @table: the top-level table structure 9101f87f0b5SEric W. Biederman * 9111f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 9121f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 9131f87f0b5SEric W. Biederman * 9141f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 9151f87f0b5SEric W. Biederman * 9161f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 9171f87f0b5SEric W. Biederman * enter a sysctl file 9181f87f0b5SEric W. Biederman * 9191f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 9201f87f0b5SEric W. Biederman * 9211f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 9221f87f0b5SEric W. Biederman * 923f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 9241f87f0b5SEric W. Biederman * 925f728019bSEric W. Biederman * child - must be %NULL. 9261f87f0b5SEric W. Biederman * 9271f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 9281f87f0b5SEric W. Biederman * 9291f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 9301f87f0b5SEric W. Biederman * 9311f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 9321f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 9331f87f0b5SEric W. Biederman * 934f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 935f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 9361f87f0b5SEric W. Biederman * 9371f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 9381f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 9391f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 9401f87f0b5SEric W. Biederman * 9411f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 9421f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 9431f87f0b5SEric W. Biederman * 9441f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 9451f87f0b5SEric W. Biederman * to the table header on success. 9461f87f0b5SEric W. Biederman */ 9476e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 9481f87f0b5SEric W. Biederman struct ctl_table_root *root, 9491f87f0b5SEric W. Biederman struct nsproxy *namespaces, 9506e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 9511f87f0b5SEric W. Biederman { 9521f87f0b5SEric W. Biederman struct ctl_table_header *header; 9531f87f0b5SEric W. Biederman struct ctl_table *new, **prevp; 9546e9d5164SEric W. Biederman const char *name, *nextname; 9556e9d5164SEric W. Biederman unsigned int npath = 0; 9561f87f0b5SEric W. Biederman struct ctl_table_set *set; 957f05e53a7SEric W. Biederman size_t path_bytes = 0; 958f05e53a7SEric W. Biederman char *new_name; 9591f87f0b5SEric W. Biederman 9601f87f0b5SEric W. Biederman /* Count the path components */ 9616e9d5164SEric W. Biederman for (name = path; name; name = nextname) { 9626e9d5164SEric W. Biederman int namelen; 9636e9d5164SEric W. Biederman nextname = strchr(name, '/'); 9646e9d5164SEric W. Biederman if (nextname) { 9656e9d5164SEric W. Biederman namelen = nextname - name; 9666e9d5164SEric W. Biederman nextname++; 9676e9d5164SEric W. Biederman } else { 9686e9d5164SEric W. Biederman namelen = strlen(name); 9696e9d5164SEric W. Biederman } 9706e9d5164SEric W. Biederman if (namelen == 0) 9716e9d5164SEric W. Biederman continue; 9726e9d5164SEric W. Biederman path_bytes += namelen + 1; 9736e9d5164SEric W. Biederman npath++; 9746e9d5164SEric W. Biederman } 9751f87f0b5SEric W. Biederman 9761f87f0b5SEric W. Biederman /* 9771f87f0b5SEric W. Biederman * For each path component, allocate a 2-element ctl_table array. 9781f87f0b5SEric W. Biederman * The first array element will be filled with the sysctl entry 9791f87f0b5SEric W. Biederman * for this, the second will be the sentinel (procname == 0). 9801f87f0b5SEric W. Biederman * 9811f87f0b5SEric W. Biederman * We allocate everything in one go so that we don't have to 9821f87f0b5SEric W. Biederman * worry about freeing additional memory in unregister_sysctl_table. 9831f87f0b5SEric W. Biederman */ 984f05e53a7SEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + path_bytes + 9851f87f0b5SEric W. Biederman (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL); 9861f87f0b5SEric W. Biederman if (!header) 9871f87f0b5SEric W. Biederman return NULL; 9881f87f0b5SEric W. Biederman 9891f87f0b5SEric W. Biederman new = (struct ctl_table *) (header + 1); 990f05e53a7SEric W. Biederman new_name = (char *)(new + (2 * npath)); 9911f87f0b5SEric W. Biederman 9921f87f0b5SEric W. Biederman /* Now connect the dots */ 9931f87f0b5SEric W. Biederman prevp = &header->ctl_table; 9946e9d5164SEric W. Biederman for (name = path; name; name = nextname) { 9956e9d5164SEric W. Biederman int namelen; 9966e9d5164SEric W. Biederman nextname = strchr(name, '/'); 9976e9d5164SEric W. Biederman if (nextname) { 9986e9d5164SEric W. Biederman namelen = nextname - name; 9996e9d5164SEric W. Biederman nextname++; 10006e9d5164SEric W. Biederman } else { 10016e9d5164SEric W. Biederman namelen = strlen(name); 10026e9d5164SEric W. Biederman } 10036e9d5164SEric W. Biederman if (namelen == 0) 10046e9d5164SEric W. Biederman continue; 10056e9d5164SEric W. Biederman memcpy(new_name, name, namelen); 10066e9d5164SEric W. Biederman new_name[namelen] = '\0'; 10076e9d5164SEric W. Biederman 1008f05e53a7SEric W. Biederman new->procname = new_name; 10091f87f0b5SEric W. Biederman new->mode = 0555; 10101f87f0b5SEric W. Biederman 10111f87f0b5SEric W. Biederman *prevp = new; 10121f87f0b5SEric W. Biederman prevp = &new->child; 10131f87f0b5SEric W. Biederman 10141f87f0b5SEric W. Biederman new += 2; 10156e9d5164SEric W. Biederman new_name += namelen + 1; 10161f87f0b5SEric W. Biederman } 10171f87f0b5SEric W. Biederman *prevp = table; 10181f87f0b5SEric W. Biederman 1019e0d04529SEric W. Biederman init_header(header, root, NULL, table); 10207c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 10217c60c48fSEric W. Biederman goto fail; 10228d6ecfccSEric W. Biederman 10231f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 10241f87f0b5SEric W. Biederman header->set = lookup_header_set(root, namespaces); 10251f87f0b5SEric W. Biederman header->attached_by = header->ctl_table; 1026a194558eSEric W. Biederman header->attached_to = &root_table[1]; 10271f87f0b5SEric W. Biederman header->parent = &root_table_header; 1028bd295b56SEric W. Biederman set = header->set; 1029bd295b56SEric W. Biederman root = header->root; 1030bd295b56SEric W. Biederman for (;;) { 10311f87f0b5SEric W. Biederman struct ctl_table_header *p; 10321f87f0b5SEric W. Biederman list_for_each_entry(p, &set->list, ctl_entry) { 10331f87f0b5SEric W. Biederman if (p->unregistering) 10341f87f0b5SEric W. Biederman continue; 10351f87f0b5SEric W. Biederman try_attach(p, header); 10361f87f0b5SEric W. Biederman } 1037bd295b56SEric W. Biederman if (root == &sysctl_table_root) 1038bd295b56SEric W. Biederman break; 1039bd295b56SEric W. Biederman root = list_entry(root->root_list.prev, 1040bd295b56SEric W. Biederman struct ctl_table_root, root_list); 1041bd295b56SEric W. Biederman set = lookup_header_set(root, namespaces); 10421f87f0b5SEric W. Biederman } 10437c60c48fSEric W. Biederman if (sysctl_check_dups(namespaces, header, path, table)) 10447c60c48fSEric W. Biederman goto fail_locked; 10458425d6aaSEric W. Biederman insert_header(header); 10461f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 10471f87f0b5SEric W. Biederman 10481f87f0b5SEric W. Biederman return header; 10497c60c48fSEric W. Biederman fail_locked: 10507c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 10517c60c48fSEric W. Biederman fail: 10527c60c48fSEric W. Biederman kfree(header); 10537c60c48fSEric W. Biederman dump_stack(); 10547c60c48fSEric W. Biederman return NULL; 10551f87f0b5SEric W. Biederman } 10561f87f0b5SEric W. Biederman 10576e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 10586e9d5164SEric W. Biederman { 10596e9d5164SEric W. Biederman int namelen; 10606e9d5164SEric W. Biederman namelen = strlen(name); 10616e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 10626e9d5164SEric W. Biederman return NULL; 10636e9d5164SEric W. Biederman memcpy(pos, name, namelen); 10646e9d5164SEric W. Biederman pos[namelen] = '/'; 10656e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 10666e9d5164SEric W. Biederman pos += namelen + 1; 10676e9d5164SEric W. Biederman return pos; 10686e9d5164SEric W. Biederman } 10696e9d5164SEric W. Biederman 1070f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1071f728019bSEric W. Biederman { 1072f728019bSEric W. Biederman int has_files = 0; 1073f728019bSEric W. Biederman int nr_subheaders = 0; 1074f728019bSEric W. Biederman struct ctl_table *entry; 1075f728019bSEric W. Biederman 1076f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1077f728019bSEric W. Biederman if (!table || !table->procname) 1078f728019bSEric W. Biederman return 1; 1079f728019bSEric W. Biederman 1080f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1081f728019bSEric W. Biederman if (entry->child) 1082f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1083f728019bSEric W. Biederman else 1084f728019bSEric W. Biederman has_files = 1; 1085f728019bSEric W. Biederman } 1086f728019bSEric W. Biederman return nr_subheaders + has_files; 1087f728019bSEric W. Biederman } 1088f728019bSEric W. Biederman 1089f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 1090f728019bSEric W. Biederman struct ctl_table_header ***subheader, 1091f728019bSEric W. Biederman struct ctl_table_root *root, struct nsproxy *namespaces, 1092f728019bSEric W. Biederman struct ctl_table *table) 1093f728019bSEric W. Biederman { 1094f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1095f728019bSEric W. Biederman struct ctl_table *entry, *files; 1096f728019bSEric W. Biederman int nr_files = 0; 1097f728019bSEric W. Biederman int nr_dirs = 0; 1098f728019bSEric W. Biederman int err = -ENOMEM; 1099f728019bSEric W. Biederman 1100f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1101f728019bSEric W. Biederman if (entry->child) 1102f728019bSEric W. Biederman nr_dirs++; 1103f728019bSEric W. Biederman else 1104f728019bSEric W. Biederman nr_files++; 1105f728019bSEric W. Biederman } 1106f728019bSEric W. Biederman 1107f728019bSEric W. Biederman files = table; 1108f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1109f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1110f728019bSEric W. Biederman struct ctl_table *new; 1111f728019bSEric W. Biederman files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), 1112f728019bSEric W. Biederman GFP_KERNEL); 1113f728019bSEric W. Biederman if (!files) 1114f728019bSEric W. Biederman goto out; 1115f728019bSEric W. Biederman 1116f728019bSEric W. Biederman ctl_table_arg = files; 1117f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1118f728019bSEric W. Biederman if (entry->child) 1119f728019bSEric W. Biederman continue; 1120f728019bSEric W. Biederman *new = *entry; 1121f728019bSEric W. Biederman new++; 1122f728019bSEric W. Biederman } 1123f728019bSEric W. Biederman } 1124f728019bSEric W. Biederman 1125f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1126f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1127f728019bSEric W. Biederman struct ctl_table_header *header; 1128f728019bSEric W. Biederman header = __register_sysctl_table(root, namespaces, path, files); 1129f728019bSEric W. Biederman if (!header) { 1130f728019bSEric W. Biederman kfree(ctl_table_arg); 1131f728019bSEric W. Biederman goto out; 1132f728019bSEric W. Biederman } 1133f728019bSEric W. Biederman 1134f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1135f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1136f728019bSEric W. Biederman **subheader = header; 1137f728019bSEric W. Biederman (*subheader)++; 1138f728019bSEric W. Biederman } 1139f728019bSEric W. Biederman 1140f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1141f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1142f728019bSEric W. Biederman char *child_pos; 1143f728019bSEric W. Biederman 1144f728019bSEric W. Biederman if (!entry->child) 1145f728019bSEric W. Biederman continue; 1146f728019bSEric W. Biederman 1147f728019bSEric W. Biederman err = -ENAMETOOLONG; 1148f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1149f728019bSEric W. Biederman if (!child_pos) 1150f728019bSEric W. Biederman goto out; 1151f728019bSEric W. Biederman 1152f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 1153f728019bSEric W. Biederman root, namespaces, entry->child); 1154f728019bSEric W. Biederman pos[0] = '\0'; 1155f728019bSEric W. Biederman if (err) 1156f728019bSEric W. Biederman goto out; 1157f728019bSEric W. Biederman } 1158f728019bSEric W. Biederman err = 0; 1159f728019bSEric W. Biederman out: 1160f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1161f728019bSEric W. Biederman return err; 1162f728019bSEric W. Biederman } 1163f728019bSEric W. Biederman 11646e9d5164SEric W. Biederman /** 11656e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 11666e9d5164SEric W. Biederman * @root: List of sysctl headers to register on 11676e9d5164SEric W. Biederman * @namespaces: Data to compute which lists of sysctl entries are visible 11686e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 11696e9d5164SEric W. Biederman * @table: the top-level table structure 11706e9d5164SEric W. Biederman * 11716e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 11726e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 11736e9d5164SEric W. Biederman * 11746e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 11756e9d5164SEric W. Biederman */ 11766e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 11776e9d5164SEric W. Biederman struct ctl_table_root *root, 11786e9d5164SEric W. Biederman struct nsproxy *namespaces, 11796e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 11806e9d5164SEric W. Biederman { 1181ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1182f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1183f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 11846e9d5164SEric W. Biederman const struct ctl_path *component; 11856e9d5164SEric W. Biederman char *new_path, *pos; 11866e9d5164SEric W. Biederman 11876e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 11886e9d5164SEric W. Biederman if (!new_path) 11896e9d5164SEric W. Biederman return NULL; 11906e9d5164SEric W. Biederman 11916e9d5164SEric W. Biederman pos[0] = '\0'; 11926e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 11936e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 11946e9d5164SEric W. Biederman if (!pos) 11956e9d5164SEric W. Biederman goto out; 11966e9d5164SEric W. Biederman } 1197ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1198ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1199ec6a5266SEric W. Biederman if (!pos) 1200ec6a5266SEric W. Biederman goto out; 1201ec6a5266SEric W. Biederman table = table->child; 1202ec6a5266SEric W. Biederman } 1203f728019bSEric W. Biederman if (nr_subheaders == 1) { 12046e9d5164SEric W. Biederman header = __register_sysctl_table(root, namespaces, new_path, table); 1205ec6a5266SEric W. Biederman if (header) 1206ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1207f728019bSEric W. Biederman } else { 1208f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1209f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1210f728019bSEric W. Biederman if (!header) 1211f728019bSEric W. Biederman goto out; 1212f728019bSEric W. Biederman 1213f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1214f728019bSEric W. Biederman subheader = subheaders; 1215f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1216f728019bSEric W. Biederman 1217f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 1218f728019bSEric W. Biederman root, namespaces, table)) 1219f728019bSEric W. Biederman goto err_register_leaves; 1220f728019bSEric W. Biederman } 1221f728019bSEric W. Biederman 12226e9d5164SEric W. Biederman out: 12236e9d5164SEric W. Biederman kfree(new_path); 12246e9d5164SEric W. Biederman return header; 1225f728019bSEric W. Biederman 1226f728019bSEric W. Biederman err_register_leaves: 1227f728019bSEric W. Biederman while (subheader > subheaders) { 1228f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1229f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1230f728019bSEric W. Biederman unregister_sysctl_table(subh); 1231f728019bSEric W. Biederman kfree(table); 1232f728019bSEric W. Biederman } 1233f728019bSEric W. Biederman kfree(header); 1234f728019bSEric W. Biederman header = NULL; 1235f728019bSEric W. Biederman goto out; 12366e9d5164SEric W. Biederman } 12376e9d5164SEric W. Biederman 12381f87f0b5SEric W. Biederman /** 12391f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 12401f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12411f87f0b5SEric W. Biederman * @table: the top-level table structure 12421f87f0b5SEric W. Biederman * 12431f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12441f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12451f87f0b5SEric W. Biederman * 12461f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 12471f87f0b5SEric W. Biederman */ 12481f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 12491f87f0b5SEric W. Biederman struct ctl_table *table) 12501f87f0b5SEric W. Biederman { 12511f87f0b5SEric W. Biederman return __register_sysctl_paths(&sysctl_table_root, current->nsproxy, 12521f87f0b5SEric W. Biederman path, table); 12531f87f0b5SEric W. Biederman } 12541f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 12551f87f0b5SEric W. Biederman 12561f87f0b5SEric W. Biederman /** 12571f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 12581f87f0b5SEric W. Biederman * @table: the top-level table structure 12591f87f0b5SEric W. Biederman * 12601f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12611f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12621f87f0b5SEric W. Biederman * 12631f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 12641f87f0b5SEric W. Biederman */ 12651f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 12661f87f0b5SEric W. Biederman { 12671f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 12681f87f0b5SEric W. Biederman 12691f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 12701f87f0b5SEric W. Biederman } 12711f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 12721f87f0b5SEric W. Biederman 1273938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1274938aaa4fSEric W. Biederman { 1275938aaa4fSEric W. Biederman if (--header->nreg) 1276938aaa4fSEric W. Biederman return; 1277938aaa4fSEric W. Biederman 1278938aaa4fSEric W. Biederman start_unregistering(header); 1279938aaa4fSEric W. Biederman if (!--header->parent->count) { 1280938aaa4fSEric W. Biederman WARN_ON(1); 1281938aaa4fSEric W. Biederman kfree_rcu(header->parent, rcu); 1282938aaa4fSEric W. Biederman } 1283938aaa4fSEric W. Biederman if (!--header->count) 1284938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 1285938aaa4fSEric W. Biederman } 1286938aaa4fSEric W. Biederman 12871f87f0b5SEric W. Biederman /** 12881f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 12891f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 12901f87f0b5SEric W. Biederman * 12911f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 12921f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 12931f87f0b5SEric W. Biederman */ 12941f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 12951f87f0b5SEric W. Biederman { 1296f728019bSEric W. Biederman int nr_subheaders; 12971f87f0b5SEric W. Biederman might_sleep(); 12981f87f0b5SEric W. Biederman 12991f87f0b5SEric W. Biederman if (header == NULL) 13001f87f0b5SEric W. Biederman return; 13011f87f0b5SEric W. Biederman 1302f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1303f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1304f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1305f728019bSEric W. Biederman int i; 1306f728019bSEric W. Biederman 1307f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1308f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1309f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1310f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1311f728019bSEric W. Biederman unregister_sysctl_table(subh); 1312f728019bSEric W. Biederman kfree(table); 1313f728019bSEric W. Biederman } 1314f728019bSEric W. Biederman kfree(header); 1315f728019bSEric W. Biederman return; 1316f728019bSEric W. Biederman } 1317f728019bSEric W. Biederman 13181f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1319938aaa4fSEric W. Biederman drop_sysctl_table(header); 13201f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13211f87f0b5SEric W. Biederman } 13221f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 13231f87f0b5SEric W. Biederman 13241f87f0b5SEric W. Biederman void setup_sysctl_set(struct ctl_table_set *p, 13251f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 13261f87f0b5SEric W. Biederman { 13271f87f0b5SEric W. Biederman INIT_LIST_HEAD(&p->list); 13281f87f0b5SEric W. Biederman p->is_seen = is_seen; 13291f87f0b5SEric W. Biederman } 13301f87f0b5SEric W. Biederman 133197324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 133297324cd8SEric W. Biederman { 133397324cd8SEric W. Biederman WARN_ON(!list_empty(&set->list)); 133497324cd8SEric W. Biederman } 13351f87f0b5SEric W. Biederman 13361e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 133777b14db5SEric W. Biederman { 1338e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1339e1675231SAlexey Dobriyan 134077b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 13419043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 13429043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 134377b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1344de4e83bdSEric W. Biederman 1345de4e83bdSEric W. Biederman return sysctl_init(); 134677b14db5SEric W. Biederman } 1347