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> 1134286d66SNick Piggin #include <linux/namei.h> 1240401530SAl Viro #include <linux/mm.h> 131f87f0b5SEric W. Biederman #include <linux/module.h> 1477b14db5SEric W. Biederman #include "internal.h" 1577b14db5SEric W. Biederman 16d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1777b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 1803a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 199043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 209043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 2177b14db5SEric W. Biederman 22f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 23f9bd6733SEric W. Biederman 24f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 25f9bd6733SEric W. Biederman { } 26f9bd6733SEric W. Biederman }; 27f9bd6733SEric W. Biederman 28f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 29f9bd6733SEric W. Biederman { 30f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 31f9bd6733SEric W. Biederman } 32f9bd6733SEric W. Biederman 33f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 34f9bd6733SEric W. Biederman { 35f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 36f9bd6733SEric W. Biederman } 37f9bd6733SEric W. Biederman 38f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 39f9bd6733SEric W. Biederman 40f9bd6733SEric W. Biederman { 41f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 42f9bd6733SEric W. Biederman } 43f9bd6733SEric W. Biederman 44f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 45f1ecf068SLucas De Marchi { 46f1ecf068SLucas De Marchi if (!poll) 47f1ecf068SLucas De Marchi return; 48f1ecf068SLucas De Marchi 49f1ecf068SLucas De Marchi atomic_inc(&poll->event); 50f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 51f1ecf068SLucas De Marchi } 52f1ecf068SLucas De Marchi 53a194558eSEric W. Biederman static struct ctl_table root_table[] = { 54a194558eSEric W. Biederman { 55a194558eSEric W. Biederman .procname = "", 567ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 57a194558eSEric W. Biederman }, 58a194558eSEric W. Biederman { } 59a194558eSEric W. Biederman }; 600e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 610e47c99dSEric W. Biederman .default_set.dir.header = { 621f87f0b5SEric W. Biederman {{.count = 1, 63938aaa4fSEric W. Biederman .nreg = 1, 64ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 650e47c99dSEric W. Biederman .ctl_table_arg = root_table, 661f87f0b5SEric W. Biederman .root = &sysctl_table_root, 671f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 687ec66d06SEric W. Biederman }, 691f87f0b5SEric W. Biederman }; 701f87f0b5SEric W. Biederman 711f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 721f87f0b5SEric W. Biederman 737ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 740e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 750e47c99dSEric W. Biederman struct ctl_table **pentry, struct nsproxy *namespaces); 760e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 770e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 787ec66d06SEric W. Biederman 796980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 806980128fSEric W. Biederman { 816980128fSEric W. Biederman if (dir->header.parent) 826980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 8387ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 846980128fSEric W. Biederman } 856980128fSEric W. Biederman 86076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 87076c3eedSEric W. Biederman { 88076c3eedSEric W. Biederman int minlen; 89076c3eedSEric W. Biederman int cmp; 90076c3eedSEric W. Biederman 91076c3eedSEric W. Biederman minlen = len1; 92076c3eedSEric W. Biederman if (minlen > len2) 93076c3eedSEric W. Biederman minlen = len2; 94076c3eedSEric W. Biederman 95076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 96076c3eedSEric W. Biederman if (cmp == 0) 97076c3eedSEric W. Biederman cmp = len1 - len2; 98076c3eedSEric W. Biederman return cmp; 99076c3eedSEric W. Biederman } 100076c3eedSEric W. Biederman 10160f126d9SEric W. Biederman /* Called under sysctl_lock */ 102076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1030e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 104076c3eedSEric W. Biederman { 105076c3eedSEric W. Biederman struct ctl_table_header *head; 106076c3eedSEric W. Biederman struct ctl_table *entry; 107ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 108076c3eedSEric W. Biederman 109ac13ac6fSEric W. Biederman while (node) 110ac13ac6fSEric W. Biederman { 111ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 112ac13ac6fSEric W. Biederman const char *procname; 113ac13ac6fSEric W. Biederman int cmp; 114ac13ac6fSEric W. Biederman 115ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 116ac13ac6fSEric W. Biederman head = ctl_node->header; 117ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 118ac13ac6fSEric W. Biederman procname = entry->procname; 119ac13ac6fSEric W. Biederman 120ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 121ac13ac6fSEric W. Biederman if (cmp < 0) 122ac13ac6fSEric W. Biederman node = node->rb_left; 123ac13ac6fSEric W. Biederman else if (cmp > 0) 124ac13ac6fSEric W. Biederman node = node->rb_right; 125ac13ac6fSEric W. Biederman else { 126076c3eedSEric W. Biederman *phead = head; 127076c3eedSEric W. Biederman return entry; 128076c3eedSEric W. Biederman } 129076c3eedSEric W. Biederman } 130076c3eedSEric W. Biederman return NULL; 131076c3eedSEric W. Biederman } 132076c3eedSEric W. Biederman 133ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 134ac13ac6fSEric W. Biederman { 135ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 136ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 137ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 138ac13ac6fSEric W. Biederman const char *name = entry->procname; 139ac13ac6fSEric W. Biederman int namelen = strlen(name); 140ac13ac6fSEric W. Biederman 141ac13ac6fSEric W. Biederman while (*p) { 142ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 143ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 144ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 145ac13ac6fSEric W. Biederman const char *parent_name; 146ac13ac6fSEric W. Biederman int cmp; 147ac13ac6fSEric W. Biederman 148ac13ac6fSEric W. Biederman parent = *p; 149ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 150ac13ac6fSEric W. Biederman parent_head = parent_node->header; 151ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 152ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 153ac13ac6fSEric W. Biederman 154ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 155ac13ac6fSEric W. Biederman if (cmp < 0) 156ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 157ac13ac6fSEric W. Biederman else if (cmp > 0) 158ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 159ac13ac6fSEric W. Biederman else { 16087ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 161ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 16287ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 163ac13ac6fSEric W. Biederman return -EEXIST; 164ac13ac6fSEric W. Biederman } 165ac13ac6fSEric W. Biederman } 166ac13ac6fSEric W. Biederman 167ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 168ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 169ac13ac6fSEric W. Biederman return 0; 170ac13ac6fSEric W. Biederman } 171ac13ac6fSEric W. Biederman 172ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 173ac13ac6fSEric W. Biederman { 174ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 175ac13ac6fSEric W. Biederman 176ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 177ac13ac6fSEric W. Biederman } 178ac13ac6fSEric W. Biederman 179e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 180e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 181ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 182e0d04529SEric W. Biederman { 1837ec66d06SEric W. Biederman head->ctl_table = table; 184e0d04529SEric W. Biederman head->ctl_table_arg = table; 185e0d04529SEric W. Biederman head->used = 0; 186e0d04529SEric W. Biederman head->count = 1; 187e0d04529SEric W. Biederman head->nreg = 1; 188e0d04529SEric W. Biederman head->unregistering = NULL; 189e0d04529SEric W. Biederman head->root = root; 190e0d04529SEric W. Biederman head->set = set; 191e0d04529SEric W. Biederman head->parent = NULL; 192ac13ac6fSEric W. Biederman head->node = node; 193ac13ac6fSEric W. Biederman if (node) { 194ac13ac6fSEric W. Biederman struct ctl_table *entry; 1954c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 196ac13ac6fSEric W. Biederman node->header = head; 197ac13ac6fSEric W. Biederman } 198ac13ac6fSEric W. Biederman } 199e0d04529SEric W. Biederman 2008425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2018425d6aaSEric W. Biederman { 202ac13ac6fSEric W. Biederman struct ctl_table *entry; 203ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 204ac13ac6fSEric W. Biederman erase_entry(head, entry); 2058425d6aaSEric W. Biederman } 2068425d6aaSEric W. Biederman 2070e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2088425d6aaSEric W. Biederman { 209ac13ac6fSEric W. Biederman struct ctl_table *entry; 2100e47c99dSEric W. Biederman int err; 2110e47c99dSEric W. Biederman 212f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 213f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 214f9bd6733SEric W. Biederman return -EROFS; 215f9bd6733SEric W. Biederman 216f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 217f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 218f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 219f9bd6733SEric W. Biederman return -EINVAL; 220f9bd6733SEric W. Biederman set_empty_dir(dir); 221f9bd6733SEric W. Biederman } 222f9bd6733SEric W. Biederman 2230e47c99dSEric W. Biederman dir->header.nreg++; 2247ec66d06SEric W. Biederman header->parent = dir; 2250e47c99dSEric W. Biederman err = insert_links(header); 2260e47c99dSEric W. Biederman if (err) 2270e47c99dSEric W. Biederman goto fail_links; 228ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 229ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 230ac13ac6fSEric W. Biederman if (err) 231ac13ac6fSEric W. Biederman goto fail; 232ac13ac6fSEric W. Biederman } 2330e47c99dSEric W. Biederman return 0; 234ac13ac6fSEric W. Biederman fail: 235ac13ac6fSEric W. Biederman erase_header(header); 236ac13ac6fSEric W. Biederman put_links(header); 2370e47c99dSEric W. Biederman fail_links: 238f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 239f9bd6733SEric W. Biederman clear_empty_dir(dir); 2400e47c99dSEric W. Biederman header->parent = NULL; 2410e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2420e47c99dSEric W. Biederman return err; 2438425d6aaSEric W. Biederman } 2448425d6aaSEric W. Biederman 2451f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2461f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2471f87f0b5SEric W. Biederman { 2481f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2491f87f0b5SEric W. Biederman return 0; 2501f87f0b5SEric W. Biederman p->used++; 2511f87f0b5SEric W. Biederman return 1; 2521f87f0b5SEric W. Biederman } 2531f87f0b5SEric W. Biederman 2541f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2551f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2561f87f0b5SEric W. Biederman { 2571f87f0b5SEric W. Biederman if (!--p->used) 2581f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2591f87f0b5SEric W. Biederman complete(p->unregistering); 2601f87f0b5SEric W. Biederman } 2611f87f0b5SEric W. Biederman 2621f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2631f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2641f87f0b5SEric W. Biederman { 2651f87f0b5SEric W. Biederman /* 2661f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2671f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2681f87f0b5SEric W. Biederman */ 2691f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2701f87f0b5SEric W. Biederman struct completion wait; 2711f87f0b5SEric W. Biederman init_completion(&wait); 2721f87f0b5SEric W. Biederman p->unregistering = &wait; 2731f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2741f87f0b5SEric W. Biederman wait_for_completion(&wait); 2751f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2761f87f0b5SEric W. Biederman } else { 2771f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 2781f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 2791f87f0b5SEric W. Biederman } 2801f87f0b5SEric W. Biederman /* 2811f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 2821f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 2831f87f0b5SEric W. Biederman */ 2848425d6aaSEric W. Biederman erase_header(p); 2851f87f0b5SEric W. Biederman } 2861f87f0b5SEric W. Biederman 2871f87f0b5SEric W. Biederman static void sysctl_head_get(struct ctl_table_header *head) 2881f87f0b5SEric W. Biederman { 2891f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2901f87f0b5SEric W. Biederman head->count++; 2911f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2921f87f0b5SEric W. Biederman } 2931f87f0b5SEric W. Biederman 2941f87f0b5SEric W. Biederman void sysctl_head_put(struct ctl_table_header *head) 2951f87f0b5SEric W. Biederman { 2961f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2971f87f0b5SEric W. Biederman if (!--head->count) 2981f87f0b5SEric W. Biederman kfree_rcu(head, rcu); 2991f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3001f87f0b5SEric W. Biederman } 3011f87f0b5SEric W. Biederman 3021f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3031f87f0b5SEric W. Biederman { 304ab4a1f24SPrasad Joshi BUG_ON(!head); 3051f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3061f87f0b5SEric W. Biederman if (!use_table(head)) 3071f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3081f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3091f87f0b5SEric W. Biederman return head; 3101f87f0b5SEric W. Biederman } 3111f87f0b5SEric W. Biederman 3121f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3131f87f0b5SEric W. Biederman { 3141f87f0b5SEric W. Biederman if (!head) 3151f87f0b5SEric W. Biederman return; 3161f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3171f87f0b5SEric W. Biederman unuse_table(head); 3181f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3191f87f0b5SEric W. Biederman } 3201f87f0b5SEric W. Biederman 3211f87f0b5SEric W. Biederman static struct ctl_table_set * 3221f87f0b5SEric W. Biederman lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) 3231f87f0b5SEric W. Biederman { 3241f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3251f87f0b5SEric W. Biederman if (root->lookup) 3261f87f0b5SEric W. Biederman set = root->lookup(root, namespaces); 3271f87f0b5SEric W. Biederman return set; 3281f87f0b5SEric W. Biederman } 3291f87f0b5SEric W. Biederman 330076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3317ec66d06SEric W. Biederman struct ctl_dir *dir, 332076c3eedSEric W. Biederman const char *name, int namelen) 333076c3eedSEric W. Biederman { 334076c3eedSEric W. Biederman struct ctl_table_header *head; 335076c3eedSEric W. Biederman struct ctl_table *entry; 336076c3eedSEric W. Biederman 337076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3380e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 339076c3eedSEric W. Biederman if (entry && use_table(head)) 340076c3eedSEric W. Biederman *phead = head; 341076c3eedSEric W. Biederman else 342076c3eedSEric W. Biederman entry = NULL; 343076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 344076c3eedSEric W. Biederman return entry; 345076c3eedSEric W. Biederman } 346076c3eedSEric W. Biederman 347ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3481f87f0b5SEric W. Biederman { 349ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3501f87f0b5SEric W. Biederman 351ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 352ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 353ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 354ac13ac6fSEric W. Biederman return ctl_node; 3551f87f0b5SEric W. Biederman } 3561f87f0b5SEric W. Biederman return NULL; 3571f87f0b5SEric W. Biederman } 3581f87f0b5SEric W. Biederman 3597ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3606a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3611f87f0b5SEric W. Biederman { 362ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3637ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 364ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3656a75ce16SEric W. Biederman 3666a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 367ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3686a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 369ac13ac6fSEric W. Biederman if (ctl_node) { 370ac13ac6fSEric W. Biederman head = ctl_node->header; 371ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 372ac13ac6fSEric W. Biederman } 3736a75ce16SEric W. Biederman *phead = head; 3746a75ce16SEric W. Biederman *pentry = entry; 3756a75ce16SEric W. Biederman } 3766a75ce16SEric W. Biederman 3777ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3786a75ce16SEric W. Biederman { 3796a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3806a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 381ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 3826a75ce16SEric W. Biederman 3836a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 3846a75ce16SEric W. Biederman unuse_table(head); 385ac13ac6fSEric W. Biederman 386ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 3876a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 388ac13ac6fSEric W. Biederman head = NULL; 389ac13ac6fSEric W. Biederman if (ctl_node) { 390ac13ac6fSEric W. Biederman head = ctl_node->header; 391ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 3926a75ce16SEric W. Biederman } 3936a75ce16SEric W. Biederman *phead = head; 3946a75ce16SEric W. Biederman *pentry = entry; 3951f87f0b5SEric W. Biederman } 3961f87f0b5SEric W. Biederman 3971f87f0b5SEric W. Biederman void register_sysctl_root(struct ctl_table_root *root) 3981f87f0b5SEric W. Biederman { 3991f87f0b5SEric W. Biederman } 4001f87f0b5SEric W. Biederman 4011f87f0b5SEric W. Biederman /* 4021f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4031f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4041f87f0b5SEric W. Biederman */ 4051f87f0b5SEric W. Biederman 4061f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4071f87f0b5SEric W. Biederman { 408091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4091f87f0b5SEric W. Biederman mode >>= 6; 410091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4111f87f0b5SEric W. Biederman mode >>= 3; 4121f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4131f87f0b5SEric W. Biederman return 0; 4141f87f0b5SEric W. Biederman return -EACCES; 4151f87f0b5SEric W. Biederman } 4161f87f0b5SEric W. Biederman 41773f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4181f87f0b5SEric W. Biederman { 41973f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4201f87f0b5SEric W. Biederman int mode; 4211f87f0b5SEric W. Biederman 4221f87f0b5SEric W. Biederman if (root->permissions) 42373f7ef43SEric W. Biederman mode = root->permissions(head, table); 4241f87f0b5SEric W. Biederman else 4251f87f0b5SEric W. Biederman mode = table->mode; 4261f87f0b5SEric W. Biederman 4271f87f0b5SEric W. Biederman return test_perm(mode, op); 4281f87f0b5SEric W. Biederman } 4291f87f0b5SEric W. Biederman 4309043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4319043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 43277b14db5SEric W. Biederman { 43377b14db5SEric W. Biederman struct inode *inode; 4349043476fSAl Viro struct proc_inode *ei; 43577b14db5SEric W. Biederman 4369043476fSAl Viro inode = new_inode(sb); 43777b14db5SEric W. Biederman if (!inode) 43877b14db5SEric W. Biederman goto out; 43977b14db5SEric W. Biederman 44085fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 44185fe4025SChristoph Hellwig 4429043476fSAl Viro sysctl_head_get(head); 44377b14db5SEric W. Biederman ei = PROC_I(inode); 4449043476fSAl Viro ei->sysctl = head; 4459043476fSAl Viro ei->sysctl_entry = table; 4469043476fSAl Viro 44777b14db5SEric W. Biederman inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 4489043476fSAl Viro inode->i_mode = table->mode; 4497ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4509043476fSAl Viro inode->i_mode |= S_IFREG; 45177b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 45277b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4539043476fSAl Viro } else { 4549043476fSAl Viro inode->i_mode |= S_IFDIR; 4559043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4569043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 457f9bd6733SEric W. Biederman if (is_empty_dir(head)) 458f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4599043476fSAl Viro } 46077b14db5SEric W. Biederman out: 46177b14db5SEric W. Biederman return inode; 46277b14db5SEric W. Biederman } 46377b14db5SEric W. Biederman 46481324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 46577b14db5SEric W. Biederman { 4663cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 4673cc3e046SEric W. Biederman if (!head) 4680e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 4693cc3e046SEric W. Biederman return sysctl_head_grab(head); 47077b14db5SEric W. Biederman } 47177b14db5SEric W. Biederman 47277b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 47300cd8dd3SAl Viro unsigned int flags) 47477b14db5SEric W. Biederman { 4759043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 4769043476fSAl Viro struct ctl_table_header *h = NULL; 4779043476fSAl Viro struct qstr *name = &dentry->d_name; 4789043476fSAl Viro struct ctl_table *p; 47977b14db5SEric W. Biederman struct inode *inode; 4809043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 4817ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 4820e47c99dSEric W. Biederman int ret; 48377b14db5SEric W. Biederman 4849043476fSAl Viro if (IS_ERR(head)) 4859043476fSAl Viro return ERR_CAST(head); 4869043476fSAl Viro 4877ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 4889043476fSAl Viro 4897ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 4909043476fSAl Viro if (!p) 49177b14db5SEric W. Biederman goto out; 49277b14db5SEric W. Biederman 4934e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 4940e47c99dSEric W. Biederman ret = sysctl_follow_link(&h, &p, current->nsproxy); 4950e47c99dSEric W. Biederman err = ERR_PTR(ret); 4960e47c99dSEric W. Biederman if (ret) 4970e47c99dSEric W. Biederman goto out; 4984e757320SEric W. Biederman } 4990e47c99dSEric W. Biederman 50077b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 5019043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 50277b14db5SEric W. Biederman if (!inode) 50377b14db5SEric W. Biederman goto out; 50477b14db5SEric W. Biederman 50577b14db5SEric W. Biederman err = NULL; 506fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 50777b14db5SEric W. Biederman d_add(dentry, inode); 50877b14db5SEric W. Biederman 50977b14db5SEric W. Biederman out: 5106bf61045SFrancesco Ruggeri if (h) 5116bf61045SFrancesco Ruggeri sysctl_head_finish(h); 51277b14db5SEric W. Biederman sysctl_head_finish(head); 51377b14db5SEric W. Biederman return err; 51477b14db5SEric W. Biederman } 51577b14db5SEric W. Biederman 5167708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 5177708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 51877b14db5SEric W. Biederman { 519496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5209043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5219043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5222a2da53bSDavid Howells ssize_t error; 5232a2da53bSDavid Howells size_t res; 52477b14db5SEric W. Biederman 5259043476fSAl Viro if (IS_ERR(head)) 5269043476fSAl Viro return PTR_ERR(head); 52777b14db5SEric W. Biederman 52877b14db5SEric W. Biederman /* 52977b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 53077b14db5SEric W. Biederman * and won't be until we finish. 53177b14db5SEric W. Biederman */ 53277b14db5SEric W. Biederman error = -EPERM; 53373f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 53477b14db5SEric W. Biederman goto out; 53577b14db5SEric W. Biederman 5369043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5379043476fSAl Viro error = -EINVAL; 5389043476fSAl Viro if (!table->proc_handler) 5399043476fSAl Viro goto out; 5409043476fSAl Viro 54177b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 54277b14db5SEric W. Biederman res = count; 5438d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 54477b14db5SEric W. Biederman if (!error) 54577b14db5SEric W. Biederman error = res; 54677b14db5SEric W. Biederman out: 54777b14db5SEric W. Biederman sysctl_head_finish(head); 54877b14db5SEric W. Biederman 54977b14db5SEric W. Biederman return error; 55077b14db5SEric W. Biederman } 55177b14db5SEric W. Biederman 5527708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 5537708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 5547708bfb1SPavel Emelyanov { 5557708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 5567708bfb1SPavel Emelyanov } 5577708bfb1SPavel Emelyanov 55877b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 55977b14db5SEric W. Biederman size_t count, loff_t *ppos) 56077b14db5SEric W. Biederman { 5617708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 56277b14db5SEric W. Biederman } 56377b14db5SEric W. Biederman 564f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 565f1ecf068SLucas De Marchi { 5664e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 567f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 568f1ecf068SLucas De Marchi 5694e474a00SLucas De Marchi /* sysctl was unregistered */ 5704e474a00SLucas De Marchi if (IS_ERR(head)) 5714e474a00SLucas De Marchi return PTR_ERR(head); 5724e474a00SLucas De Marchi 573f1ecf068SLucas De Marchi if (table->poll) 574f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 575f1ecf068SLucas De Marchi 5764e474a00SLucas De Marchi sysctl_head_finish(head); 5774e474a00SLucas De Marchi 578f1ecf068SLucas De Marchi return 0; 579f1ecf068SLucas De Marchi } 580f1ecf068SLucas De Marchi 581f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 582f1ecf068SLucas De Marchi { 583496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5844e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 585f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 586f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 5874e474a00SLucas De Marchi unsigned long event; 5884e474a00SLucas De Marchi 5894e474a00SLucas De Marchi /* sysctl was unregistered */ 5904e474a00SLucas De Marchi if (IS_ERR(head)) 5914e474a00SLucas De Marchi return POLLERR | POLLHUP; 592f1ecf068SLucas De Marchi 593f1ecf068SLucas De Marchi if (!table->proc_handler) 594f1ecf068SLucas De Marchi goto out; 595f1ecf068SLucas De Marchi 596f1ecf068SLucas De Marchi if (!table->poll) 597f1ecf068SLucas De Marchi goto out; 598f1ecf068SLucas De Marchi 5994e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 600f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 601f1ecf068SLucas De Marchi 602f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 603f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 604f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 605f1ecf068SLucas De Marchi } 606f1ecf068SLucas De Marchi 607f1ecf068SLucas De Marchi out: 6084e474a00SLucas De Marchi sysctl_head_finish(head); 6094e474a00SLucas De Marchi 610f1ecf068SLucas De Marchi return ret; 611f1ecf068SLucas De Marchi } 61277b14db5SEric W. Biederman 613f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 614f0c3b509SAl Viro struct dir_context *ctx, 6159043476fSAl Viro struct ctl_table_header *head, 6169043476fSAl Viro struct ctl_table *table) 61777b14db5SEric W. Biederman { 618f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 61977b14db5SEric W. Biederman struct inode *inode; 62077b14db5SEric W. Biederman struct qstr qname; 62177b14db5SEric W. Biederman ino_t ino = 0; 62277b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 62377b14db5SEric W. Biederman 62477b14db5SEric W. Biederman qname.name = table->procname; 62577b14db5SEric W. Biederman qname.len = strlen(table->procname); 62677b14db5SEric W. Biederman qname.hash = full_name_hash(qname.name, qname.len); 62777b14db5SEric W. Biederman 62877b14db5SEric W. Biederman child = d_lookup(dir, &qname); 62977b14db5SEric W. Biederman if (!child) { 6309043476fSAl Viro child = d_alloc(dir, &qname); 6319043476fSAl Viro if (child) { 6329043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 6339043476fSAl Viro if (!inode) { 6349043476fSAl Viro dput(child); 635f0c3b509SAl Viro return false; 6369043476fSAl Viro } else { 637fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 6389043476fSAl Viro d_add(child, inode); 63977b14db5SEric W. Biederman } 6409043476fSAl Viro } else { 641f0c3b509SAl Viro return false; 64277b14db5SEric W. Biederman } 64377b14db5SEric W. Biederman } 6442b0143b5SDavid Howells inode = d_inode(child); 64577b14db5SEric W. Biederman ino = inode->i_ino; 64677b14db5SEric W. Biederman type = inode->i_mode >> 12; 64777b14db5SEric W. Biederman dput(child); 648f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 6499043476fSAl Viro } 6509043476fSAl Viro 651f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 652f0c3b509SAl Viro struct dir_context *ctx, 6530e47c99dSEric W. Biederman struct ctl_table_header *head, 6540e47c99dSEric W. Biederman struct ctl_table *table) 6550e47c99dSEric W. Biederman { 656f0c3b509SAl Viro bool ret = true; 6570e47c99dSEric W. Biederman head = sysctl_head_grab(head); 6580e47c99dSEric W. Biederman 6594e757320SEric W. Biederman if (S_ISLNK(table->mode)) { 6600e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 661f0c3b509SAl Viro int err = sysctl_follow_link(&head, &table, current->nsproxy); 6620e47c99dSEric W. Biederman if (err) 6630e47c99dSEric W. Biederman goto out; 6644e757320SEric W. Biederman } 6650e47c99dSEric W. Biederman 666f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 6670e47c99dSEric W. Biederman out: 6680e47c99dSEric W. Biederman sysctl_head_finish(head); 6690e47c99dSEric W. Biederman return ret; 6700e47c99dSEric W. Biederman } 6710e47c99dSEric W. Biederman 672e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 6739043476fSAl Viro unsigned long *pos, struct file *file, 674f0c3b509SAl Viro struct dir_context *ctx) 6759043476fSAl Viro { 676f0c3b509SAl Viro bool res; 6779043476fSAl Viro 678f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 679f0c3b509SAl Viro return true; 6809043476fSAl Viro 6810e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 682f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 6830e47c99dSEric W. Biederman else 684f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 6859043476fSAl Viro 686f0c3b509SAl Viro if (res) 687f0c3b509SAl Viro ctx->pos = *pos; 6886a75ce16SEric W. Biederman 6896a75ce16SEric W. Biederman return res; 69077b14db5SEric W. Biederman } 69177b14db5SEric W. Biederman 692f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 69377b14db5SEric W. Biederman { 694f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 6959043476fSAl Viro struct ctl_table_header *h = NULL; 6966a75ce16SEric W. Biederman struct ctl_table *entry; 6977ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 69877b14db5SEric W. Biederman unsigned long pos; 69977b14db5SEric W. Biederman 7009043476fSAl Viro if (IS_ERR(head)) 7019043476fSAl Viro return PTR_ERR(head); 7029043476fSAl Viro 7037ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 70477b14db5SEric W. Biederman 705f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 706f0c3b509SAl Viro return 0; 707f0c3b509SAl Viro 70877b14db5SEric W. Biederman pos = 2; 70977b14db5SEric W. Biederman 7107ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 711f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7129043476fSAl Viro sysctl_head_finish(h); 7139043476fSAl Viro break; 71477b14db5SEric W. Biederman } 71577b14db5SEric W. Biederman } 71677b14db5SEric W. Biederman sysctl_head_finish(head); 717f0c3b509SAl Viro return 0; 71877b14db5SEric W. Biederman } 71977b14db5SEric W. Biederman 72010556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 72177b14db5SEric W. Biederman { 72277b14db5SEric W. Biederman /* 72377b14db5SEric W. Biederman * sysctl entries that are not writeable, 72477b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 72577b14db5SEric W. Biederman */ 726f696a365SMiklos Szeredi struct ctl_table_header *head; 727f696a365SMiklos Szeredi struct ctl_table *table; 72877b14db5SEric W. Biederman int error; 72977b14db5SEric W. Biederman 730f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 731f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 732f696a365SMiklos Szeredi return -EACCES; 733f696a365SMiklos Szeredi 734f696a365SMiklos Szeredi head = grab_header(inode); 7359043476fSAl Viro if (IS_ERR(head)) 7369043476fSAl Viro return PTR_ERR(head); 73777b14db5SEric W. Biederman 738f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 7399043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 7409043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 7419043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 74273f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 7439043476fSAl Viro 74477b14db5SEric W. Biederman sysctl_head_finish(head); 74577b14db5SEric W. Biederman return error; 74677b14db5SEric W. Biederman } 74777b14db5SEric W. Biederman 74877b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 74977b14db5SEric W. Biederman { 7502b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 75177b14db5SEric W. Biederman int error; 75277b14db5SEric W. Biederman 75377b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 75477b14db5SEric W. Biederman return -EPERM; 75577b14db5SEric W. Biederman 75677b14db5SEric W. Biederman error = inode_change_ok(inode, attr); 7571025774cSChristoph Hellwig if (error) 75877b14db5SEric W. Biederman return error; 7591025774cSChristoph Hellwig 7601025774cSChristoph Hellwig setattr_copy(inode, attr); 7611025774cSChristoph Hellwig mark_inode_dirty(inode); 7621025774cSChristoph Hellwig return 0; 76377b14db5SEric W. Biederman } 76477b14db5SEric W. Biederman 7659043476fSAl Viro static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 7669043476fSAl Viro { 7672b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 7689043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 7699043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 7709043476fSAl Viro 7719043476fSAl Viro if (IS_ERR(head)) 7729043476fSAl Viro return PTR_ERR(head); 7739043476fSAl Viro 7749043476fSAl Viro generic_fillattr(inode, stat); 7759043476fSAl Viro if (table) 7769043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 7779043476fSAl Viro 7789043476fSAl Viro sysctl_head_finish(head); 7799043476fSAl Viro return 0; 7809043476fSAl Viro } 7819043476fSAl Viro 78277b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 783f1ecf068SLucas De Marchi .open = proc_sys_open, 784f1ecf068SLucas De Marchi .poll = proc_sys_poll, 78577b14db5SEric W. Biederman .read = proc_sys_read, 78677b14db5SEric W. Biederman .write = proc_sys_write, 7876038f373SArnd Bergmann .llseek = default_llseek, 7889043476fSAl Viro }; 7899043476fSAl Viro 7909043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 791887df078SPavel Emelyanov .read = generic_read_dir, 792f0c3b509SAl Viro .iterate = proc_sys_readdir, 7933222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 79477b14db5SEric W. Biederman }; 79577b14db5SEric W. Biederman 79603a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 7979043476fSAl Viro .permission = proc_sys_permission, 7989043476fSAl Viro .setattr = proc_sys_setattr, 7999043476fSAl Viro .getattr = proc_sys_getattr, 8009043476fSAl Viro }; 8019043476fSAl Viro 8029043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 80377b14db5SEric W. Biederman .lookup = proc_sys_lookup, 80477b14db5SEric W. Biederman .permission = proc_sys_permission, 80577b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8069043476fSAl Viro .getattr = proc_sys_getattr, 80777b14db5SEric W. Biederman }; 80877b14db5SEric W. Biederman 8090b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 81077b14db5SEric W. Biederman { 8110b728e19SAl Viro if (flags & LOOKUP_RCU) 81234286d66SNick Piggin return -ECHILD; 8132b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8149043476fSAl Viro } 8159043476fSAl Viro 816fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8179043476fSAl Viro { 8182b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 8199043476fSAl Viro } 8209043476fSAl Viro 8211f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8221f87f0b5SEric W. Biederman { 8231f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8241f87f0b5SEric W. Biederman int res; 8251f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8261f87f0b5SEric W. Biederman if (p->unregistering) 8271f87f0b5SEric W. Biederman res = 0; 8281f87f0b5SEric W. Biederman else if (!set->is_seen) 8291f87f0b5SEric W. Biederman res = 1; 8301f87f0b5SEric W. Biederman else 8311f87f0b5SEric W. Biederman res = set->is_seen(set); 8321f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 8331f87f0b5SEric W. Biederman return res; 8341f87f0b5SEric W. Biederman } 8351f87f0b5SEric W. Biederman 836da53be12SLinus Torvalds static int proc_sys_compare(const struct dentry *parent, const struct dentry *dentry, 837621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 8389043476fSAl Viro { 839dfef6dcdSAl Viro struct ctl_table_header *head; 840da53be12SLinus Torvalds struct inode *inode; 841da53be12SLinus Torvalds 84231e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 84331e6b01fSNick Piggin * that inode here can be NULL */ 844dfef6dcdSAl Viro /* AV: can it, indeed? */ 8452b0143b5SDavid Howells inode = d_inode_rcu(dentry); 84631e6b01fSNick Piggin if (!inode) 847dfef6dcdSAl Viro return 1; 848621e155aSNick Piggin if (name->len != len) 8499043476fSAl Viro return 1; 850621e155aSNick Piggin if (memcmp(name->name, str, len)) 8519043476fSAl Viro return 1; 852dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 853dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 85477b14db5SEric W. Biederman } 85577b14db5SEric W. Biederman 856d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 85777b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 8589043476fSAl Viro .d_delete = proc_sys_delete, 8599043476fSAl Viro .d_compare = proc_sys_compare, 86077b14db5SEric W. Biederman }; 86177b14db5SEric W. Biederman 8620e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 8637ec66d06SEric W. Biederman const char *name, int namelen) 8641f87f0b5SEric W. Biederman { 8657ec66d06SEric W. Biederman struct ctl_table_header *head; 8667ec66d06SEric W. Biederman struct ctl_table *entry; 8671f87f0b5SEric W. Biederman 8680e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 8697ec66d06SEric W. Biederman if (!entry) 8707ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 87151f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 8727ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 87351f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 8741f87f0b5SEric W. Biederman } 8751f87f0b5SEric W. Biederman 8767ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 8777ec66d06SEric W. Biederman const char *name, int namelen) 8781f87f0b5SEric W. Biederman { 8797ec66d06SEric W. Biederman struct ctl_table *table; 8807ec66d06SEric W. Biederman struct ctl_dir *new; 881ac13ac6fSEric W. Biederman struct ctl_node *node; 8827ec66d06SEric W. Biederman char *new_name; 8831f87f0b5SEric W. Biederman 884ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 885ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 886ac13ac6fSEric W. Biederman GFP_KERNEL); 8877ec66d06SEric W. Biederman if (!new) 8887ec66d06SEric W. Biederman return NULL; 8897ec66d06SEric W. Biederman 890ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 891ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 8927ec66d06SEric W. Biederman new_name = (char *)(table + 2); 8937ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 8947ec66d06SEric W. Biederman new_name[namelen] = '\0'; 8957ec66d06SEric W. Biederman table[0].procname = new_name; 8967ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 897ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 8987ec66d06SEric W. Biederman 8997ec66d06SEric W. Biederman return new; 9001f87f0b5SEric W. Biederman } 9011f87f0b5SEric W. Biederman 90260f126d9SEric W. Biederman /** 90360f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 90460f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 90560f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 90660f126d9SEric W. Biederman * @namelen: The length of name 90760f126d9SEric W. Biederman * 90860f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 90960f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 91060f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 91160f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 91260f126d9SEric W. Biederman * simply dropped. 91360f126d9SEric W. Biederman */ 9140e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9150e47c99dSEric W. Biederman const char *name, int namelen) 9167ec66d06SEric W. Biederman { 9170e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9187ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9190eb97f38SEric W. Biederman int err; 9207ec66d06SEric W. Biederman 9217ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9220e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9237ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9247ec66d06SEric W. Biederman goto found; 9257ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9267ec66d06SEric W. Biederman goto failed; 9277ec66d06SEric W. Biederman 9287ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9297ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 9307ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9317ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 9327ec66d06SEric W. Biederman if (!new) 9337ec66d06SEric W. Biederman goto failed; 9347ec66d06SEric W. Biederman 93560f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 9360e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9377ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9387ec66d06SEric W. Biederman goto found; 9397ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9407ec66d06SEric W. Biederman goto failed; 9417ec66d06SEric W. Biederman 94260f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 9430eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 9440eb97f38SEric W. Biederman subdir = ERR_PTR(err); 9450eb97f38SEric W. Biederman if (err) 9460e47c99dSEric W. Biederman goto failed; 9477ec66d06SEric W. Biederman subdir = new; 9487ec66d06SEric W. Biederman found: 9497ec66d06SEric W. Biederman subdir->header.nreg++; 9507ec66d06SEric W. Biederman failed: 951a1c83681SViresh Kumar if (IS_ERR(subdir)) { 95287ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 9536980128fSEric W. Biederman sysctl_print_dir(dir); 95487ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 9557ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 9561f87f0b5SEric W. Biederman } 9577ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 9587ec66d06SEric W. Biederman if (new) 9597ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 9607ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9617ec66d06SEric W. Biederman return subdir; 9621f87f0b5SEric W. Biederman } 9631f87f0b5SEric W. Biederman 9640e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 9650e47c99dSEric W. Biederman { 9660e47c99dSEric W. Biederman struct ctl_dir *parent; 9670e47c99dSEric W. Biederman const char *procname; 9680e47c99dSEric W. Biederman if (!dir->header.parent) 9690e47c99dSEric W. Biederman return &set->dir; 9700e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 9710e47c99dSEric W. Biederman if (IS_ERR(parent)) 9720e47c99dSEric W. Biederman return parent; 9730e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 9740e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 9750e47c99dSEric W. Biederman } 9760e47c99dSEric W. Biederman 9770e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 9780e47c99dSEric W. Biederman struct ctl_table **pentry, struct nsproxy *namespaces) 9790e47c99dSEric W. Biederman { 9800e47c99dSEric W. Biederman struct ctl_table_header *head; 9810e47c99dSEric W. Biederman struct ctl_table_root *root; 9820e47c99dSEric W. Biederman struct ctl_table_set *set; 9830e47c99dSEric W. Biederman struct ctl_table *entry; 9840e47c99dSEric W. Biederman struct ctl_dir *dir; 9850e47c99dSEric W. Biederman int ret; 9860e47c99dSEric W. Biederman 9870e47c99dSEric W. Biederman ret = 0; 9880e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 9890e47c99dSEric W. Biederman root = (*pentry)->data; 9900e47c99dSEric W. Biederman set = lookup_header_set(root, namespaces); 9910e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 9920e47c99dSEric W. Biederman if (IS_ERR(dir)) 9930e47c99dSEric W. Biederman ret = PTR_ERR(dir); 9940e47c99dSEric W. Biederman else { 9950e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 9960e47c99dSEric W. Biederman head = NULL; 9970e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 9980e47c99dSEric W. Biederman ret = -ENOENT; 9990e47c99dSEric W. Biederman if (entry && use_table(head)) { 10000e47c99dSEric W. Biederman unuse_table(*phead); 10010e47c99dSEric W. Biederman *phead = head; 10020e47c99dSEric W. Biederman *pentry = entry; 10030e47c99dSEric W. Biederman ret = 0; 10040e47c99dSEric W. Biederman } 10050e47c99dSEric W. Biederman } 10060e47c99dSEric W. Biederman 10070e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10080e47c99dSEric W. Biederman return ret; 10090e47c99dSEric W. Biederman } 10100e47c99dSEric W. Biederman 10117c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10127c60c48fSEric W. Biederman { 10137c60c48fSEric W. Biederman struct va_format vaf; 10147c60c48fSEric W. Biederman va_list args; 10157c60c48fSEric W. Biederman 10167c60c48fSEric W. Biederman va_start(args, fmt); 10177c60c48fSEric W. Biederman vaf.fmt = fmt; 10187c60c48fSEric W. Biederman vaf.va = &args; 10197c60c48fSEric W. Biederman 102087ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10217c60c48fSEric W. Biederman path, table->procname, &vaf); 10227c60c48fSEric W. Biederman 10237c60c48fSEric W. Biederman va_end(args); 10247c60c48fSEric W. Biederman return -EINVAL; 10257c60c48fSEric W. Biederman } 10267c60c48fSEric W. Biederman 10277c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 10287c60c48fSEric W. Biederman { 10297c60c48fSEric W. Biederman int err = 0; 10307c60c48fSEric W. Biederman for (; table->procname; table++) { 10317c60c48fSEric W. Biederman if (table->child) 10327c60c48fSEric W. Biederman err = sysctl_err(path, table, "Not a file"); 10337c60c48fSEric W. Biederman 10341f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 10351f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 10361f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 10371f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 10381f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 10391f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 10401f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 10411f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 10421f87f0b5SEric W. Biederman if (!table->data) 10437c60c48fSEric W. Biederman err = sysctl_err(path, table, "No data"); 10441f87f0b5SEric W. Biederman if (!table->maxlen) 10457c60c48fSEric W. Biederman err = sysctl_err(path, table, "No maxlen"); 10461f87f0b5SEric W. Biederman } 10471f87f0b5SEric W. Biederman if (!table->proc_handler) 10487c60c48fSEric W. Biederman err = sysctl_err(path, table, "No proc_handler"); 10497c60c48fSEric W. Biederman 10507c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 10517c60c48fSEric W. Biederman err = sysctl_err(path, table, "bogus .mode 0%o", 10527c60c48fSEric W. Biederman table->mode); 10531f87f0b5SEric W. Biederman } 10547c60c48fSEric W. Biederman return err; 10551f87f0b5SEric W. Biederman } 10561f87f0b5SEric W. Biederman 10570e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 10580e47c99dSEric W. Biederman struct ctl_table_root *link_root) 10590e47c99dSEric W. Biederman { 10600e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 10610e47c99dSEric W. Biederman struct ctl_table_header *links; 1062ac13ac6fSEric W. Biederman struct ctl_node *node; 10630e47c99dSEric W. Biederman char *link_name; 10640e47c99dSEric W. Biederman int nr_entries, name_bytes; 10650e47c99dSEric W. Biederman 10660e47c99dSEric W. Biederman name_bytes = 0; 10670e47c99dSEric W. Biederman nr_entries = 0; 10680e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 10690e47c99dSEric W. Biederman nr_entries++; 10700e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 10710e47c99dSEric W. Biederman } 10720e47c99dSEric W. Biederman 10730e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1074ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 10750e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 10760e47c99dSEric W. Biederman name_bytes, 10770e47c99dSEric W. Biederman GFP_KERNEL); 10780e47c99dSEric W. Biederman 10790e47c99dSEric W. Biederman if (!links) 10800e47c99dSEric W. Biederman return NULL; 10810e47c99dSEric W. Biederman 1082ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1083ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 10840e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 10850e47c99dSEric W. Biederman 10860e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 10870e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 10880e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 10890e47c99dSEric W. Biederman link->procname = link_name; 10900e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 10910e47c99dSEric W. Biederman link->data = link_root; 10920e47c99dSEric W. Biederman link_name += len; 10930e47c99dSEric W. Biederman } 1094ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 10950e47c99dSEric W. Biederman links->nreg = nr_entries; 10960e47c99dSEric W. Biederman 10970e47c99dSEric W. Biederman return links; 10980e47c99dSEric W. Biederman } 10990e47c99dSEric W. Biederman 11000e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11010e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11020e47c99dSEric W. Biederman { 11030e47c99dSEric W. Biederman struct ctl_table_header *head; 11040e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11050e47c99dSEric W. Biederman 11060e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11070e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11080e47c99dSEric W. Biederman const char *procname = entry->procname; 11090e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11100e47c99dSEric W. Biederman if (!link) 11110e47c99dSEric W. Biederman return false; 11120e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 11130e47c99dSEric W. Biederman continue; 11140e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 11150e47c99dSEric W. Biederman continue; 11160e47c99dSEric W. Biederman return false; 11170e47c99dSEric W. Biederman } 11180e47c99dSEric W. Biederman 11190e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 11200e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11210e47c99dSEric W. Biederman const char *procname = entry->procname; 11220e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11230e47c99dSEric W. Biederman head->nreg++; 11240e47c99dSEric W. Biederman } 11250e47c99dSEric W. Biederman return true; 11260e47c99dSEric W. Biederman } 11270e47c99dSEric W. Biederman 11280e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 11290e47c99dSEric W. Biederman { 11300e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 11310e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 11320e47c99dSEric W. Biederman struct ctl_table_header *links; 11330e47c99dSEric W. Biederman int err; 11340e47c99dSEric W. Biederman 11350e47c99dSEric W. Biederman if (head->set == root_set) 11360e47c99dSEric W. Biederman return 0; 11370e47c99dSEric W. Biederman 11380e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 11390e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 11400e47c99dSEric W. Biederman return 0; 11410e47c99dSEric W. Biederman 11420e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 11430e47c99dSEric W. Biederman return 0; 11440e47c99dSEric W. Biederman 11450e47c99dSEric W. Biederman core_parent->header.nreg++; 11460e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 11470e47c99dSEric W. Biederman 11480e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 11490e47c99dSEric W. Biederman 11500e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 11510e47c99dSEric W. Biederman err = -ENOMEM; 11520e47c99dSEric W. Biederman if (!links) 11530e47c99dSEric W. Biederman goto out; 11540e47c99dSEric W. Biederman 11550e47c99dSEric W. Biederman err = 0; 11560e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 11570e47c99dSEric W. Biederman kfree(links); 11580e47c99dSEric W. Biederman goto out; 11590e47c99dSEric W. Biederman } 11600e47c99dSEric W. Biederman 11610e47c99dSEric W. Biederman err = insert_header(core_parent, links); 11620e47c99dSEric W. Biederman if (err) 11630e47c99dSEric W. Biederman kfree(links); 11640e47c99dSEric W. Biederman out: 11650e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 11660e47c99dSEric W. Biederman return err; 11670e47c99dSEric W. Biederman } 11680e47c99dSEric W. Biederman 11691f87f0b5SEric W. Biederman /** 1170f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 117160a47a2eSEric W. Biederman * @set: Sysctl tree to register on 11721f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 11731f87f0b5SEric W. Biederman * @table: the top-level table structure 11741f87f0b5SEric W. Biederman * 11751f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 11761f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 11771f87f0b5SEric W. Biederman * 11781f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 11791f87f0b5SEric W. Biederman * 11801f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 11811f87f0b5SEric W. Biederman * enter a sysctl file 11821f87f0b5SEric W. Biederman * 11831f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 11841f87f0b5SEric W. Biederman * 11851f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 11861f87f0b5SEric W. Biederman * 1187f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 11881f87f0b5SEric W. Biederman * 1189f728019bSEric W. Biederman * child - must be %NULL. 11901f87f0b5SEric W. Biederman * 11911f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 11921f87f0b5SEric W. Biederman * 11931f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 11941f87f0b5SEric W. Biederman * 11951f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 11961f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 11971f87f0b5SEric W. Biederman * 1198f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1199f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12001f87f0b5SEric W. Biederman * 12011f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12021f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12031f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12041f87f0b5SEric W. Biederman * 12051f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12061f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12071f87f0b5SEric W. Biederman * 12081f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 12091f87f0b5SEric W. Biederman * to the table header on success. 12101f87f0b5SEric W. Biederman */ 12116e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 121260a47a2eSEric W. Biederman struct ctl_table_set *set, 12136e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 12141f87f0b5SEric W. Biederman { 121560a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 12161f87f0b5SEric W. Biederman struct ctl_table_header *header; 12176e9d5164SEric W. Biederman const char *name, *nextname; 12187ec66d06SEric W. Biederman struct ctl_dir *dir; 1219ac13ac6fSEric W. Biederman struct ctl_table *entry; 1220ac13ac6fSEric W. Biederman struct ctl_node *node; 1221ac13ac6fSEric W. Biederman int nr_entries = 0; 12221f87f0b5SEric W. Biederman 1223ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1224ac13ac6fSEric W. Biederman nr_entries++; 1225ac13ac6fSEric W. Biederman 1226ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1227ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 12281f87f0b5SEric W. Biederman if (!header) 12291f87f0b5SEric W. Biederman return NULL; 12301f87f0b5SEric W. Biederman 1231ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1232ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 12337c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 12347c60c48fSEric W. Biederman goto fail; 12358d6ecfccSEric W. Biederman 12361f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 12370e47c99dSEric W. Biederman dir = &set->dir; 123860f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 12397ec66d06SEric W. Biederman dir->header.nreg++; 12407ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 12417ec66d06SEric W. Biederman 12427ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 12437ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 12447ec66d06SEric W. Biederman int namelen; 12457ec66d06SEric W. Biederman nextname = strchr(name, '/'); 12467ec66d06SEric W. Biederman if (nextname) { 12477ec66d06SEric W. Biederman namelen = nextname - name; 12487ec66d06SEric W. Biederman nextname++; 12497ec66d06SEric W. Biederman } else { 12507ec66d06SEric W. Biederman namelen = strlen(name); 12517ec66d06SEric W. Biederman } 12527ec66d06SEric W. Biederman if (namelen == 0) 12531f87f0b5SEric W. Biederman continue; 12547ec66d06SEric W. Biederman 12550e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 12567ec66d06SEric W. Biederman if (IS_ERR(dir)) 12577ec66d06SEric W. Biederman goto fail; 12581f87f0b5SEric W. Biederman } 12590e47c99dSEric W. Biederman 12607ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 12610e47c99dSEric W. Biederman if (insert_header(dir, header)) 12620e47c99dSEric W. Biederman goto fail_put_dir_locked; 12630e47c99dSEric W. Biederman 12647ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 12651f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 12661f87f0b5SEric W. Biederman 12671f87f0b5SEric W. Biederman return header; 12680e47c99dSEric W. Biederman 12697ec66d06SEric W. Biederman fail_put_dir_locked: 12707ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 12717c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 12727c60c48fSEric W. Biederman fail: 12737c60c48fSEric W. Biederman kfree(header); 12747c60c48fSEric W. Biederman dump_stack(); 12757c60c48fSEric W. Biederman return NULL; 12761f87f0b5SEric W. Biederman } 12771f87f0b5SEric W. Biederman 1278fea478d4SEric W. Biederman /** 1279fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1280fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1281fea478d4SEric W. Biederman * @table: the table structure 1282fea478d4SEric W. Biederman * 1283fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1284fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1285fea478d4SEric W. Biederman * 1286fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1287fea478d4SEric W. Biederman */ 1288fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1289fea478d4SEric W. Biederman { 1290fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1291fea478d4SEric W. Biederman path, table); 1292fea478d4SEric W. Biederman } 1293fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1294fea478d4SEric W. Biederman 12956e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 12966e9d5164SEric W. Biederman { 12976e9d5164SEric W. Biederman int namelen; 12986e9d5164SEric W. Biederman namelen = strlen(name); 12996e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 13006e9d5164SEric W. Biederman return NULL; 13016e9d5164SEric W. Biederman memcpy(pos, name, namelen); 13026e9d5164SEric W. Biederman pos[namelen] = '/'; 13036e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 13046e9d5164SEric W. Biederman pos += namelen + 1; 13056e9d5164SEric W. Biederman return pos; 13066e9d5164SEric W. Biederman } 13076e9d5164SEric W. Biederman 1308f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1309f728019bSEric W. Biederman { 1310f728019bSEric W. Biederman int has_files = 0; 1311f728019bSEric W. Biederman int nr_subheaders = 0; 1312f728019bSEric W. Biederman struct ctl_table *entry; 1313f728019bSEric W. Biederman 1314f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1315f728019bSEric W. Biederman if (!table || !table->procname) 1316f728019bSEric W. Biederman return 1; 1317f728019bSEric W. Biederman 1318f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1319f728019bSEric W. Biederman if (entry->child) 1320f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1321f728019bSEric W. Biederman else 1322f728019bSEric W. Biederman has_files = 1; 1323f728019bSEric W. Biederman } 1324f728019bSEric W. Biederman return nr_subheaders + has_files; 1325f728019bSEric W. Biederman } 1326f728019bSEric W. Biederman 1327f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 132860a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1329f728019bSEric W. Biederman struct ctl_table *table) 1330f728019bSEric W. Biederman { 1331f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1332f728019bSEric W. Biederman struct ctl_table *entry, *files; 1333f728019bSEric W. Biederman int nr_files = 0; 1334f728019bSEric W. Biederman int nr_dirs = 0; 1335f728019bSEric W. Biederman int err = -ENOMEM; 1336f728019bSEric W. Biederman 1337f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1338f728019bSEric W. Biederman if (entry->child) 1339f728019bSEric W. Biederman nr_dirs++; 1340f728019bSEric W. Biederman else 1341f728019bSEric W. Biederman nr_files++; 1342f728019bSEric W. Biederman } 1343f728019bSEric W. Biederman 1344f728019bSEric W. Biederman files = table; 1345f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1346f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1347f728019bSEric W. Biederman struct ctl_table *new; 1348f728019bSEric W. Biederman files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), 1349f728019bSEric W. Biederman GFP_KERNEL); 1350f728019bSEric W. Biederman if (!files) 1351f728019bSEric W. Biederman goto out; 1352f728019bSEric W. Biederman 1353f728019bSEric W. Biederman ctl_table_arg = files; 1354f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1355f728019bSEric W. Biederman if (entry->child) 1356f728019bSEric W. Biederman continue; 1357f728019bSEric W. Biederman *new = *entry; 1358f728019bSEric W. Biederman new++; 1359f728019bSEric W. Biederman } 1360f728019bSEric W. Biederman } 1361f728019bSEric W. Biederman 1362f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1363f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1364f728019bSEric W. Biederman struct ctl_table_header *header; 136560a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1366f728019bSEric W. Biederman if (!header) { 1367f728019bSEric W. Biederman kfree(ctl_table_arg); 1368f728019bSEric W. Biederman goto out; 1369f728019bSEric W. Biederman } 1370f728019bSEric W. Biederman 1371f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1372f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1373f728019bSEric W. Biederman **subheader = header; 1374f728019bSEric W. Biederman (*subheader)++; 1375f728019bSEric W. Biederman } 1376f728019bSEric W. Biederman 1377f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1378f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1379f728019bSEric W. Biederman char *child_pos; 1380f728019bSEric W. Biederman 1381f728019bSEric W. Biederman if (!entry->child) 1382f728019bSEric W. Biederman continue; 1383f728019bSEric W. Biederman 1384f728019bSEric W. Biederman err = -ENAMETOOLONG; 1385f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1386f728019bSEric W. Biederman if (!child_pos) 1387f728019bSEric W. Biederman goto out; 1388f728019bSEric W. Biederman 1389f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 139060a47a2eSEric W. Biederman set, entry->child); 1391f728019bSEric W. Biederman pos[0] = '\0'; 1392f728019bSEric W. Biederman if (err) 1393f728019bSEric W. Biederman goto out; 1394f728019bSEric W. Biederman } 1395f728019bSEric W. Biederman err = 0; 1396f728019bSEric W. Biederman out: 1397f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1398f728019bSEric W. Biederman return err; 1399f728019bSEric W. Biederman } 1400f728019bSEric W. Biederman 14016e9d5164SEric W. Biederman /** 14026e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 140360a47a2eSEric W. Biederman * @set: Sysctl tree to register on 14046e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14056e9d5164SEric W. Biederman * @table: the top-level table structure 14066e9d5164SEric W. Biederman * 14076e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14086e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14096e9d5164SEric W. Biederman * 14106e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 14116e9d5164SEric W. Biederman */ 14126e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 141360a47a2eSEric W. Biederman struct ctl_table_set *set, 14146e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 14156e9d5164SEric W. Biederman { 1416ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1417f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1418f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 14196e9d5164SEric W. Biederman const struct ctl_path *component; 14206e9d5164SEric W. Biederman char *new_path, *pos; 14216e9d5164SEric W. Biederman 14226e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 14236e9d5164SEric W. Biederman if (!new_path) 14246e9d5164SEric W. Biederman return NULL; 14256e9d5164SEric W. Biederman 14266e9d5164SEric W. Biederman pos[0] = '\0'; 14276e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 14286e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 14296e9d5164SEric W. Biederman if (!pos) 14306e9d5164SEric W. Biederman goto out; 14316e9d5164SEric W. Biederman } 1432ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1433ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1434ec6a5266SEric W. Biederman if (!pos) 1435ec6a5266SEric W. Biederman goto out; 1436ec6a5266SEric W. Biederman table = table->child; 1437ec6a5266SEric W. Biederman } 1438f728019bSEric W. Biederman if (nr_subheaders == 1) { 143960a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1440ec6a5266SEric W. Biederman if (header) 1441ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1442f728019bSEric W. Biederman } else { 1443f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1444f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1445f728019bSEric W. Biederman if (!header) 1446f728019bSEric W. Biederman goto out; 1447f728019bSEric W. Biederman 1448f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1449f728019bSEric W. Biederman subheader = subheaders; 1450f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1451f728019bSEric W. Biederman 1452f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 145360a47a2eSEric W. Biederman set, table)) 1454f728019bSEric W. Biederman goto err_register_leaves; 1455f728019bSEric W. Biederman } 1456f728019bSEric W. Biederman 14576e9d5164SEric W. Biederman out: 14586e9d5164SEric W. Biederman kfree(new_path); 14596e9d5164SEric W. Biederman return header; 1460f728019bSEric W. Biederman 1461f728019bSEric W. Biederman err_register_leaves: 1462f728019bSEric W. Biederman while (subheader > subheaders) { 1463f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1464f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1465f728019bSEric W. Biederman unregister_sysctl_table(subh); 1466f728019bSEric W. Biederman kfree(table); 1467f728019bSEric W. Biederman } 1468f728019bSEric W. Biederman kfree(header); 1469f728019bSEric W. Biederman header = NULL; 1470f728019bSEric W. Biederman goto out; 14716e9d5164SEric W. Biederman } 14726e9d5164SEric W. Biederman 14731f87f0b5SEric W. Biederman /** 14741f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 14751f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14761f87f0b5SEric W. Biederman * @table: the top-level table structure 14771f87f0b5SEric W. Biederman * 14781f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14791f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14801f87f0b5SEric W. Biederman * 14811f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 14821f87f0b5SEric W. Biederman */ 14831f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 14841f87f0b5SEric W. Biederman struct ctl_table *table) 14851f87f0b5SEric W. Biederman { 148660a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 14871f87f0b5SEric W. Biederman path, table); 14881f87f0b5SEric W. Biederman } 14891f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 14901f87f0b5SEric W. Biederman 14911f87f0b5SEric W. Biederman /** 14921f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 14931f87f0b5SEric W. Biederman * @table: the top-level table structure 14941f87f0b5SEric W. Biederman * 14951f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14961f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14971f87f0b5SEric W. Biederman * 14981f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 14991f87f0b5SEric W. Biederman */ 15001f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 15011f87f0b5SEric W. Biederman { 15021f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 15031f87f0b5SEric W. Biederman 15041f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 15051f87f0b5SEric W. Biederman } 15061f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 15071f87f0b5SEric W. Biederman 15080e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 15090e47c99dSEric W. Biederman { 15100e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 15110e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 15120e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 15130e47c99dSEric W. Biederman struct ctl_dir *core_parent; 15140e47c99dSEric W. Biederman struct ctl_table *entry; 15150e47c99dSEric W. Biederman 15160e47c99dSEric W. Biederman if (header->set == root_set) 15170e47c99dSEric W. Biederman return; 15180e47c99dSEric W. Biederman 15190e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 15200e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 15210e47c99dSEric W. Biederman return; 15220e47c99dSEric W. Biederman 15230e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 15240e47c99dSEric W. Biederman struct ctl_table_header *link_head; 15250e47c99dSEric W. Biederman struct ctl_table *link; 15260e47c99dSEric W. Biederman const char *name = entry->procname; 15270e47c99dSEric W. Biederman 15280e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 15290e47c99dSEric W. Biederman if (link && 15300e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 15310e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 15320e47c99dSEric W. Biederman drop_sysctl_table(link_head); 15330e47c99dSEric W. Biederman } 15340e47c99dSEric W. Biederman else { 153587ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 15360e47c99dSEric W. Biederman sysctl_print_dir(parent); 153787ebdc00SAndrew Morton pr_cont("/%s\n", name); 15380e47c99dSEric W. Biederman } 15390e47c99dSEric W. Biederman } 15400e47c99dSEric W. Biederman } 15410e47c99dSEric W. Biederman 1542938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1543938aaa4fSEric W. Biederman { 15447ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 15457ec66d06SEric W. Biederman 1546938aaa4fSEric W. Biederman if (--header->nreg) 1547938aaa4fSEric W. Biederman return; 1548938aaa4fSEric W. Biederman 15490e47c99dSEric W. Biederman put_links(header); 1550938aaa4fSEric W. Biederman start_unregistering(header); 1551938aaa4fSEric W. Biederman if (!--header->count) 1552938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 15537ec66d06SEric W. Biederman 15547ec66d06SEric W. Biederman if (parent) 15557ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1556938aaa4fSEric W. Biederman } 1557938aaa4fSEric W. Biederman 15581f87f0b5SEric W. Biederman /** 15591f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 15601f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 15611f87f0b5SEric W. Biederman * 15621f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 15631f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 15641f87f0b5SEric W. Biederman */ 15651f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 15661f87f0b5SEric W. Biederman { 1567f728019bSEric W. Biederman int nr_subheaders; 15681f87f0b5SEric W. Biederman might_sleep(); 15691f87f0b5SEric W. Biederman 15701f87f0b5SEric W. Biederman if (header == NULL) 15711f87f0b5SEric W. Biederman return; 15721f87f0b5SEric W. Biederman 1573f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1574f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1575f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1576f728019bSEric W. Biederman int i; 1577f728019bSEric W. Biederman 1578f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1579f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1580f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1581f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1582f728019bSEric W. Biederman unregister_sysctl_table(subh); 1583f728019bSEric W. Biederman kfree(table); 1584f728019bSEric W. Biederman } 1585f728019bSEric W. Biederman kfree(header); 1586f728019bSEric W. Biederman return; 1587f728019bSEric W. Biederman } 1588f728019bSEric W. Biederman 15891f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1590938aaa4fSEric W. Biederman drop_sysctl_table(header); 15911f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 15921f87f0b5SEric W. Biederman } 15931f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 15941f87f0b5SEric W. Biederman 15950e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 15969eb47c26SEric W. Biederman struct ctl_table_root *root, 15971f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 15981f87f0b5SEric W. Biederman { 15991347440dSDan Carpenter memset(set, 0, sizeof(*set)); 16000e47c99dSEric W. Biederman set->is_seen = is_seen; 1601ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 16021f87f0b5SEric W. Biederman } 16031f87f0b5SEric W. Biederman 160497324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 160597324cd8SEric W. Biederman { 1606ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 160797324cd8SEric W. Biederman } 16081f87f0b5SEric W. Biederman 16091e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 161077b14db5SEric W. Biederman { 1611e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1612e1675231SAlexey Dobriyan 161377b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 16149043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 16159043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 161677b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1617de4e83bdSEric W. Biederman 1618de4e83bdSEric W. Biederman return sysctl_init(); 161977b14db5SEric W. Biederman } 1620