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 22f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 23f1ecf068SLucas De Marchi { 24f1ecf068SLucas De Marchi if (!poll) 25f1ecf068SLucas De Marchi return; 26f1ecf068SLucas De Marchi 27f1ecf068SLucas De Marchi atomic_inc(&poll->event); 28f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 29f1ecf068SLucas De Marchi } 30f1ecf068SLucas De Marchi 31a194558eSEric W. Biederman static struct ctl_table root_table[] = { 32a194558eSEric W. Biederman { 33a194558eSEric W. Biederman .procname = "", 347ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 35a194558eSEric W. Biederman }, 36a194558eSEric W. Biederman { } 37a194558eSEric W. Biederman }; 380e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 390e47c99dSEric W. Biederman .default_set.dir.header = { 401f87f0b5SEric W. Biederman {{.count = 1, 41938aaa4fSEric W. Biederman .nreg = 1, 42ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 430e47c99dSEric W. Biederman .ctl_table_arg = root_table, 441f87f0b5SEric W. Biederman .root = &sysctl_table_root, 451f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 467ec66d06SEric W. Biederman }, 471f87f0b5SEric W. Biederman }; 481f87f0b5SEric W. Biederman 491f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 501f87f0b5SEric W. Biederman 517ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 520e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 530e47c99dSEric W. Biederman struct ctl_table **pentry, struct nsproxy *namespaces); 540e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 550e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 567ec66d06SEric W. Biederman 576980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 586980128fSEric W. Biederman { 596980128fSEric W. Biederman if (dir->header.parent) 606980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 6187ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 626980128fSEric W. Biederman } 636980128fSEric W. Biederman 64076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 65076c3eedSEric W. Biederman { 66076c3eedSEric W. Biederman int minlen; 67076c3eedSEric W. Biederman int cmp; 68076c3eedSEric W. Biederman 69076c3eedSEric W. Biederman minlen = len1; 70076c3eedSEric W. Biederman if (minlen > len2) 71076c3eedSEric W. Biederman minlen = len2; 72076c3eedSEric W. Biederman 73076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 74076c3eedSEric W. Biederman if (cmp == 0) 75076c3eedSEric W. Biederman cmp = len1 - len2; 76076c3eedSEric W. Biederman return cmp; 77076c3eedSEric W. Biederman } 78076c3eedSEric W. Biederman 7960f126d9SEric W. Biederman /* Called under sysctl_lock */ 80076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 810e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 82076c3eedSEric W. Biederman { 83076c3eedSEric W. Biederman struct ctl_table_header *head; 84076c3eedSEric W. Biederman struct ctl_table *entry; 85ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 86076c3eedSEric W. Biederman 87ac13ac6fSEric W. Biederman while (node) 88ac13ac6fSEric W. Biederman { 89ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 90ac13ac6fSEric W. Biederman const char *procname; 91ac13ac6fSEric W. Biederman int cmp; 92ac13ac6fSEric W. Biederman 93ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 94ac13ac6fSEric W. Biederman head = ctl_node->header; 95ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 96ac13ac6fSEric W. Biederman procname = entry->procname; 97ac13ac6fSEric W. Biederman 98ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 99ac13ac6fSEric W. Biederman if (cmp < 0) 100ac13ac6fSEric W. Biederman node = node->rb_left; 101ac13ac6fSEric W. Biederman else if (cmp > 0) 102ac13ac6fSEric W. Biederman node = node->rb_right; 103ac13ac6fSEric W. Biederman else { 104076c3eedSEric W. Biederman *phead = head; 105076c3eedSEric W. Biederman return entry; 106076c3eedSEric W. Biederman } 107076c3eedSEric W. Biederman } 108076c3eedSEric W. Biederman return NULL; 109076c3eedSEric W. Biederman } 110076c3eedSEric W. Biederman 111ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 112ac13ac6fSEric W. Biederman { 113ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 114ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 115ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 116ac13ac6fSEric W. Biederman const char *name = entry->procname; 117ac13ac6fSEric W. Biederman int namelen = strlen(name); 118ac13ac6fSEric W. Biederman 119ac13ac6fSEric W. Biederman while (*p) { 120ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 121ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 122ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 123ac13ac6fSEric W. Biederman const char *parent_name; 124ac13ac6fSEric W. Biederman int cmp; 125ac13ac6fSEric W. Biederman 126ac13ac6fSEric W. Biederman parent = *p; 127ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 128ac13ac6fSEric W. Biederman parent_head = parent_node->header; 129ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 130ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 131ac13ac6fSEric W. Biederman 132ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 133ac13ac6fSEric W. Biederman if (cmp < 0) 134ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 135ac13ac6fSEric W. Biederman else if (cmp > 0) 136ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 137ac13ac6fSEric W. Biederman else { 13887ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 139ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 14087ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 141ac13ac6fSEric W. Biederman return -EEXIST; 142ac13ac6fSEric W. Biederman } 143ac13ac6fSEric W. Biederman } 144ac13ac6fSEric W. Biederman 145ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 146ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 147ac13ac6fSEric W. Biederman return 0; 148ac13ac6fSEric W. Biederman } 149ac13ac6fSEric W. Biederman 150ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 151ac13ac6fSEric W. Biederman { 152ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 153ac13ac6fSEric W. Biederman 154ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 155ac13ac6fSEric W. Biederman } 156ac13ac6fSEric W. Biederman 157e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 158e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 159ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 160e0d04529SEric W. Biederman { 1617ec66d06SEric W. Biederman head->ctl_table = table; 162e0d04529SEric W. Biederman head->ctl_table_arg = table; 163e0d04529SEric W. Biederman head->used = 0; 164e0d04529SEric W. Biederman head->count = 1; 165e0d04529SEric W. Biederman head->nreg = 1; 166e0d04529SEric W. Biederman head->unregistering = NULL; 167e0d04529SEric W. Biederman head->root = root; 168e0d04529SEric W. Biederman head->set = set; 169e0d04529SEric W. Biederman head->parent = NULL; 170ac13ac6fSEric W. Biederman head->node = node; 171ac13ac6fSEric W. Biederman if (node) { 172ac13ac6fSEric W. Biederman struct ctl_table *entry; 1734c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 174ac13ac6fSEric W. Biederman node->header = head; 175ac13ac6fSEric W. Biederman } 176ac13ac6fSEric W. Biederman } 177e0d04529SEric W. Biederman 1788425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 1798425d6aaSEric W. Biederman { 180ac13ac6fSEric W. Biederman struct ctl_table *entry; 181ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 182ac13ac6fSEric W. Biederman erase_entry(head, entry); 1838425d6aaSEric W. Biederman } 1848425d6aaSEric W. Biederman 1850e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 1868425d6aaSEric W. Biederman { 187ac13ac6fSEric W. Biederman struct ctl_table *entry; 1880e47c99dSEric W. Biederman int err; 1890e47c99dSEric W. Biederman 1900e47c99dSEric W. Biederman dir->header.nreg++; 1917ec66d06SEric W. Biederman header->parent = dir; 1920e47c99dSEric W. Biederman err = insert_links(header); 1930e47c99dSEric W. Biederman if (err) 1940e47c99dSEric W. Biederman goto fail_links; 195ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 196ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 197ac13ac6fSEric W. Biederman if (err) 198ac13ac6fSEric W. Biederman goto fail; 199ac13ac6fSEric W. Biederman } 2000e47c99dSEric W. Biederman return 0; 201ac13ac6fSEric W. Biederman fail: 202ac13ac6fSEric W. Biederman erase_header(header); 203ac13ac6fSEric W. Biederman put_links(header); 2040e47c99dSEric W. Biederman fail_links: 2050e47c99dSEric W. Biederman header->parent = NULL; 2060e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2070e47c99dSEric W. Biederman return err; 2088425d6aaSEric W. Biederman } 2098425d6aaSEric W. Biederman 2101f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2111f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2121f87f0b5SEric W. Biederman { 2131f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2141f87f0b5SEric W. Biederman return 0; 2151f87f0b5SEric W. Biederman p->used++; 2161f87f0b5SEric W. Biederman return 1; 2171f87f0b5SEric W. Biederman } 2181f87f0b5SEric W. Biederman 2191f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2201f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2211f87f0b5SEric W. Biederman { 2221f87f0b5SEric W. Biederman if (!--p->used) 2231f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2241f87f0b5SEric W. Biederman complete(p->unregistering); 2251f87f0b5SEric W. Biederman } 2261f87f0b5SEric W. Biederman 2271f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2281f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2291f87f0b5SEric W. Biederman { 2301f87f0b5SEric W. Biederman /* 2311f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2321f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2331f87f0b5SEric W. Biederman */ 2341f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2351f87f0b5SEric W. Biederman struct completion wait; 2361f87f0b5SEric W. Biederman init_completion(&wait); 2371f87f0b5SEric W. Biederman p->unregistering = &wait; 2381f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2391f87f0b5SEric W. Biederman wait_for_completion(&wait); 2401f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2411f87f0b5SEric W. Biederman } else { 2421f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 2431f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 2441f87f0b5SEric W. Biederman } 2451f87f0b5SEric W. Biederman /* 2461f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 2471f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 2481f87f0b5SEric W. Biederman */ 2498425d6aaSEric W. Biederman erase_header(p); 2501f87f0b5SEric W. Biederman } 2511f87f0b5SEric W. Biederman 2521f87f0b5SEric W. Biederman static void sysctl_head_get(struct ctl_table_header *head) 2531f87f0b5SEric W. Biederman { 2541f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2551f87f0b5SEric W. Biederman head->count++; 2561f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2571f87f0b5SEric W. Biederman } 2581f87f0b5SEric W. Biederman 2591f87f0b5SEric W. Biederman void sysctl_head_put(struct ctl_table_header *head) 2601f87f0b5SEric W. Biederman { 2611f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2621f87f0b5SEric W. Biederman if (!--head->count) 2631f87f0b5SEric W. Biederman kfree_rcu(head, rcu); 2641f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2651f87f0b5SEric W. Biederman } 2661f87f0b5SEric W. Biederman 2671f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 2681f87f0b5SEric W. Biederman { 269ab4a1f24SPrasad Joshi BUG_ON(!head); 2701f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2711f87f0b5SEric W. Biederman if (!use_table(head)) 2721f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 2731f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2741f87f0b5SEric W. Biederman return head; 2751f87f0b5SEric W. Biederman } 2761f87f0b5SEric W. Biederman 2771f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 2781f87f0b5SEric W. Biederman { 2791f87f0b5SEric W. Biederman if (!head) 2801f87f0b5SEric W. Biederman return; 2811f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 2821f87f0b5SEric W. Biederman unuse_table(head); 2831f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2841f87f0b5SEric W. Biederman } 2851f87f0b5SEric W. Biederman 2861f87f0b5SEric W. Biederman static struct ctl_table_set * 2871f87f0b5SEric W. Biederman lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) 2881f87f0b5SEric W. Biederman { 2891f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 2901f87f0b5SEric W. Biederman if (root->lookup) 2911f87f0b5SEric W. Biederman set = root->lookup(root, namespaces); 2921f87f0b5SEric W. Biederman return set; 2931f87f0b5SEric W. Biederman } 2941f87f0b5SEric W. Biederman 295076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 2967ec66d06SEric W. Biederman struct ctl_dir *dir, 297076c3eedSEric W. Biederman const char *name, int namelen) 298076c3eedSEric W. Biederman { 299076c3eedSEric W. Biederman struct ctl_table_header *head; 300076c3eedSEric W. Biederman struct ctl_table *entry; 301076c3eedSEric W. Biederman 302076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3030e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 304076c3eedSEric W. Biederman if (entry && use_table(head)) 305076c3eedSEric W. Biederman *phead = head; 306076c3eedSEric W. Biederman else 307076c3eedSEric W. Biederman entry = NULL; 308076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 309076c3eedSEric W. Biederman return entry; 310076c3eedSEric W. Biederman } 311076c3eedSEric W. Biederman 312ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3131f87f0b5SEric W. Biederman { 314ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3151f87f0b5SEric W. Biederman 316ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 317ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 318ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 319ac13ac6fSEric W. Biederman return ctl_node; 3201f87f0b5SEric W. Biederman } 3211f87f0b5SEric W. Biederman return NULL; 3221f87f0b5SEric W. Biederman } 3231f87f0b5SEric W. Biederman 3247ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3256a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3261f87f0b5SEric W. Biederman { 327ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3287ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 329ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3306a75ce16SEric W. Biederman 3316a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 332ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3336a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 334ac13ac6fSEric W. Biederman if (ctl_node) { 335ac13ac6fSEric W. Biederman head = ctl_node->header; 336ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 337ac13ac6fSEric W. Biederman } 3386a75ce16SEric W. Biederman *phead = head; 3396a75ce16SEric W. Biederman *pentry = entry; 3406a75ce16SEric W. Biederman } 3416a75ce16SEric W. Biederman 3427ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3436a75ce16SEric W. Biederman { 3446a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3456a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 346ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 3476a75ce16SEric W. Biederman 3486a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 3496a75ce16SEric W. Biederman unuse_table(head); 350ac13ac6fSEric W. Biederman 351ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 3526a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 353ac13ac6fSEric W. Biederman head = NULL; 354ac13ac6fSEric W. Biederman if (ctl_node) { 355ac13ac6fSEric W. Biederman head = ctl_node->header; 356ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 3576a75ce16SEric W. Biederman } 3586a75ce16SEric W. Biederman *phead = head; 3596a75ce16SEric W. Biederman *pentry = entry; 3601f87f0b5SEric W. Biederman } 3611f87f0b5SEric W. Biederman 3621f87f0b5SEric W. Biederman void register_sysctl_root(struct ctl_table_root *root) 3631f87f0b5SEric W. Biederman { 3641f87f0b5SEric W. Biederman } 3651f87f0b5SEric W. Biederman 3661f87f0b5SEric W. Biederman /* 3671f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 3681f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 3691f87f0b5SEric W. Biederman */ 3701f87f0b5SEric W. Biederman 3711f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 3721f87f0b5SEric W. Biederman { 373091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 3741f87f0b5SEric W. Biederman mode >>= 6; 375091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 3761f87f0b5SEric W. Biederman mode >>= 3; 3771f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 3781f87f0b5SEric W. Biederman return 0; 3791f87f0b5SEric W. Biederman return -EACCES; 3801f87f0b5SEric W. Biederman } 3811f87f0b5SEric W. Biederman 38273f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 3831f87f0b5SEric W. Biederman { 38473f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 3851f87f0b5SEric W. Biederman int mode; 3861f87f0b5SEric W. Biederman 3871f87f0b5SEric W. Biederman if (root->permissions) 38873f7ef43SEric W. Biederman mode = root->permissions(head, table); 3891f87f0b5SEric W. Biederman else 3901f87f0b5SEric W. Biederman mode = table->mode; 3911f87f0b5SEric W. Biederman 3921f87f0b5SEric W. Biederman return test_perm(mode, op); 3931f87f0b5SEric W. Biederman } 3941f87f0b5SEric W. Biederman 3959043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 3969043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 39777b14db5SEric W. Biederman { 39877b14db5SEric W. Biederman struct inode *inode; 3999043476fSAl Viro struct proc_inode *ei; 40077b14db5SEric W. Biederman 4019043476fSAl Viro inode = new_inode(sb); 40277b14db5SEric W. Biederman if (!inode) 40377b14db5SEric W. Biederman goto out; 40477b14db5SEric W. Biederman 40585fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 40685fe4025SChristoph Hellwig 4079043476fSAl Viro sysctl_head_get(head); 40877b14db5SEric W. Biederman ei = PROC_I(inode); 4099043476fSAl Viro ei->sysctl = head; 4109043476fSAl Viro ei->sysctl_entry = table; 4119043476fSAl Viro 41277b14db5SEric W. Biederman inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 4139043476fSAl Viro inode->i_mode = table->mode; 4147ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4159043476fSAl Viro inode->i_mode |= S_IFREG; 41677b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 41777b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4189043476fSAl Viro } else { 4199043476fSAl Viro inode->i_mode |= S_IFDIR; 4209043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4219043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 4229043476fSAl Viro } 42377b14db5SEric W. Biederman out: 42477b14db5SEric W. Biederman return inode; 42577b14db5SEric W. Biederman } 42677b14db5SEric W. Biederman 42781324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 42877b14db5SEric W. Biederman { 4293cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 4303cc3e046SEric W. Biederman if (!head) 4310e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 4323cc3e046SEric W. Biederman return sysctl_head_grab(head); 43377b14db5SEric W. Biederman } 43477b14db5SEric W. Biederman 43577b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 43600cd8dd3SAl Viro unsigned int flags) 43777b14db5SEric W. Biederman { 4389043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 4399043476fSAl Viro struct ctl_table_header *h = NULL; 4409043476fSAl Viro struct qstr *name = &dentry->d_name; 4419043476fSAl Viro struct ctl_table *p; 44277b14db5SEric W. Biederman struct inode *inode; 4439043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 4447ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 4450e47c99dSEric W. Biederman int ret; 44677b14db5SEric W. Biederman 4479043476fSAl Viro if (IS_ERR(head)) 4489043476fSAl Viro return ERR_CAST(head); 4499043476fSAl Viro 4507ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 4519043476fSAl Viro 4527ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 4539043476fSAl Viro if (!p) 45477b14db5SEric W. Biederman goto out; 45577b14db5SEric W. Biederman 4564e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 4570e47c99dSEric W. Biederman ret = sysctl_follow_link(&h, &p, current->nsproxy); 4580e47c99dSEric W. Biederman err = ERR_PTR(ret); 4590e47c99dSEric W. Biederman if (ret) 4600e47c99dSEric W. Biederman goto out; 4614e757320SEric W. Biederman } 4620e47c99dSEric W. Biederman 46377b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 4649043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 46577b14db5SEric W. Biederman if (!inode) 46677b14db5SEric W. Biederman goto out; 46777b14db5SEric W. Biederman 46877b14db5SEric W. Biederman err = NULL; 469fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 47077b14db5SEric W. Biederman d_add(dentry, inode); 47177b14db5SEric W. Biederman 47277b14db5SEric W. Biederman out: 4736bf61045SFrancesco Ruggeri if (h) 4746bf61045SFrancesco Ruggeri sysctl_head_finish(h); 47577b14db5SEric W. Biederman sysctl_head_finish(head); 47677b14db5SEric W. Biederman return err; 47777b14db5SEric W. Biederman } 47877b14db5SEric W. Biederman 4797708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 4807708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 48177b14db5SEric W. Biederman { 482496ad9aaSAl Viro struct inode *inode = file_inode(filp); 4839043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 4849043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 4852a2da53bSDavid Howells ssize_t error; 4862a2da53bSDavid Howells size_t res; 48777b14db5SEric W. Biederman 4889043476fSAl Viro if (IS_ERR(head)) 4899043476fSAl Viro return PTR_ERR(head); 49077b14db5SEric W. Biederman 49177b14db5SEric W. Biederman /* 49277b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 49377b14db5SEric W. Biederman * and won't be until we finish. 49477b14db5SEric W. Biederman */ 49577b14db5SEric W. Biederman error = -EPERM; 49673f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 49777b14db5SEric W. Biederman goto out; 49877b14db5SEric W. Biederman 4999043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5009043476fSAl Viro error = -EINVAL; 5019043476fSAl Viro if (!table->proc_handler) 5029043476fSAl Viro goto out; 5039043476fSAl Viro 50477b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 50577b14db5SEric W. Biederman res = count; 5068d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 50777b14db5SEric W. Biederman if (!error) 50877b14db5SEric W. Biederman error = res; 50977b14db5SEric W. Biederman out: 51077b14db5SEric W. Biederman sysctl_head_finish(head); 51177b14db5SEric W. Biederman 51277b14db5SEric W. Biederman return error; 51377b14db5SEric W. Biederman } 51477b14db5SEric W. Biederman 5157708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 5167708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 5177708bfb1SPavel Emelyanov { 5187708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 5197708bfb1SPavel Emelyanov } 5207708bfb1SPavel Emelyanov 52177b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 52277b14db5SEric W. Biederman size_t count, loff_t *ppos) 52377b14db5SEric W. Biederman { 5247708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 52577b14db5SEric W. Biederman } 52677b14db5SEric W. Biederman 527f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 528f1ecf068SLucas De Marchi { 5294e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 530f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 531f1ecf068SLucas De Marchi 5324e474a00SLucas De Marchi /* sysctl was unregistered */ 5334e474a00SLucas De Marchi if (IS_ERR(head)) 5344e474a00SLucas De Marchi return PTR_ERR(head); 5354e474a00SLucas De Marchi 536f1ecf068SLucas De Marchi if (table->poll) 537f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 538f1ecf068SLucas De Marchi 5394e474a00SLucas De Marchi sysctl_head_finish(head); 5404e474a00SLucas De Marchi 541f1ecf068SLucas De Marchi return 0; 542f1ecf068SLucas De Marchi } 543f1ecf068SLucas De Marchi 544f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 545f1ecf068SLucas De Marchi { 546496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5474e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 548f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 549f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 5504e474a00SLucas De Marchi unsigned long event; 5514e474a00SLucas De Marchi 5524e474a00SLucas De Marchi /* sysctl was unregistered */ 5534e474a00SLucas De Marchi if (IS_ERR(head)) 5544e474a00SLucas De Marchi return POLLERR | POLLHUP; 555f1ecf068SLucas De Marchi 556f1ecf068SLucas De Marchi if (!table->proc_handler) 557f1ecf068SLucas De Marchi goto out; 558f1ecf068SLucas De Marchi 559f1ecf068SLucas De Marchi if (!table->poll) 560f1ecf068SLucas De Marchi goto out; 561f1ecf068SLucas De Marchi 5624e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 563f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 564f1ecf068SLucas De Marchi 565f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 566f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 567f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 568f1ecf068SLucas De Marchi } 569f1ecf068SLucas De Marchi 570f1ecf068SLucas De Marchi out: 5714e474a00SLucas De Marchi sysctl_head_finish(head); 5724e474a00SLucas De Marchi 573f1ecf068SLucas De Marchi return ret; 574f1ecf068SLucas De Marchi } 57577b14db5SEric W. Biederman 57677b14db5SEric W. Biederman static int proc_sys_fill_cache(struct file *filp, void *dirent, 5779043476fSAl Viro filldir_t filldir, 5789043476fSAl Viro struct ctl_table_header *head, 5799043476fSAl Viro struct ctl_table *table) 58077b14db5SEric W. Biederman { 58177b14db5SEric W. Biederman struct dentry *child, *dir = filp->f_path.dentry; 58277b14db5SEric W. Biederman struct inode *inode; 58377b14db5SEric W. Biederman struct qstr qname; 58477b14db5SEric W. Biederman ino_t ino = 0; 58577b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 58677b14db5SEric W. Biederman 58777b14db5SEric W. Biederman qname.name = table->procname; 58877b14db5SEric W. Biederman qname.len = strlen(table->procname); 58977b14db5SEric W. Biederman qname.hash = full_name_hash(qname.name, qname.len); 59077b14db5SEric W. Biederman 59177b14db5SEric W. Biederman child = d_lookup(dir, &qname); 59277b14db5SEric W. Biederman if (!child) { 5939043476fSAl Viro child = d_alloc(dir, &qname); 5949043476fSAl Viro if (child) { 5959043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 5969043476fSAl Viro if (!inode) { 5979043476fSAl Viro dput(child); 5989043476fSAl Viro return -ENOMEM; 5999043476fSAl Viro } else { 600fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 6019043476fSAl Viro d_add(child, inode); 60277b14db5SEric W. Biederman } 6039043476fSAl Viro } else { 6049043476fSAl Viro return -ENOMEM; 60577b14db5SEric W. Biederman } 60677b14db5SEric W. Biederman } 60777b14db5SEric W. Biederman inode = child->d_inode; 60877b14db5SEric W. Biederman ino = inode->i_ino; 60977b14db5SEric W. Biederman type = inode->i_mode >> 12; 61077b14db5SEric W. Biederman dput(child); 6119043476fSAl Viro return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); 6129043476fSAl Viro } 6139043476fSAl Viro 6140e47c99dSEric W. Biederman static int proc_sys_link_fill_cache(struct file *filp, void *dirent, 6150e47c99dSEric W. Biederman filldir_t filldir, 6160e47c99dSEric W. Biederman struct ctl_table_header *head, 6170e47c99dSEric W. Biederman struct ctl_table *table) 6180e47c99dSEric W. Biederman { 6190e47c99dSEric W. Biederman int err, ret = 0; 6200e47c99dSEric W. Biederman head = sysctl_head_grab(head); 6210e47c99dSEric W. Biederman 6224e757320SEric W. Biederman if (S_ISLNK(table->mode)) { 6230e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 6240e47c99dSEric W. Biederman err = sysctl_follow_link(&head, &table, current->nsproxy); 6250e47c99dSEric W. Biederman if (err) 6260e47c99dSEric W. Biederman goto out; 6274e757320SEric W. Biederman } 6280e47c99dSEric W. Biederman 6290e47c99dSEric W. Biederman ret = proc_sys_fill_cache(filp, dirent, filldir, head, table); 6300e47c99dSEric W. Biederman out: 6310e47c99dSEric W. Biederman sysctl_head_finish(head); 6320e47c99dSEric W. Biederman return ret; 6330e47c99dSEric W. Biederman } 6340e47c99dSEric W. Biederman 6359043476fSAl Viro static int scan(struct ctl_table_header *head, ctl_table *table, 6369043476fSAl Viro unsigned long *pos, struct file *file, 6379043476fSAl Viro void *dirent, filldir_t filldir) 6389043476fSAl Viro { 6399043476fSAl Viro int res; 6409043476fSAl Viro 6416a75ce16SEric W. Biederman if ((*pos)++ < file->f_pos) 6429043476fSAl Viro return 0; 64377b14db5SEric W. Biederman 6440e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 6450e47c99dSEric W. Biederman res = proc_sys_link_fill_cache(file, dirent, filldir, head, table); 6460e47c99dSEric W. Biederman else 64777b14db5SEric W. Biederman res = proc_sys_fill_cache(file, dirent, filldir, head, table); 64877b14db5SEric W. Biederman 6496a75ce16SEric W. Biederman if (res == 0) 6506a75ce16SEric W. Biederman file->f_pos = *pos; 6516a75ce16SEric W. Biederman 6526a75ce16SEric W. Biederman return res; 65377b14db5SEric W. Biederman } 65477b14db5SEric W. Biederman 65577b14db5SEric W. Biederman static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) 65677b14db5SEric W. Biederman { 6579043476fSAl Viro struct dentry *dentry = filp->f_path.dentry; 65877b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 6599043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 6609043476fSAl Viro struct ctl_table_header *h = NULL; 6616a75ce16SEric W. Biederman struct ctl_table *entry; 6627ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 66377b14db5SEric W. Biederman unsigned long pos; 6649043476fSAl Viro int ret = -EINVAL; 66577b14db5SEric W. Biederman 6669043476fSAl Viro if (IS_ERR(head)) 6679043476fSAl Viro return PTR_ERR(head); 6689043476fSAl Viro 6697ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 67077b14db5SEric W. Biederman 67177b14db5SEric W. Biederman ret = 0; 67277b14db5SEric W. Biederman /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ 67377b14db5SEric W. Biederman if (filp->f_pos == 0) { 67477b14db5SEric W. Biederman if (filldir(dirent, ".", 1, filp->f_pos, 67577b14db5SEric W. Biederman inode->i_ino, DT_DIR) < 0) 67677b14db5SEric W. Biederman goto out; 67777b14db5SEric W. Biederman filp->f_pos++; 67877b14db5SEric W. Biederman } 67977b14db5SEric W. Biederman if (filp->f_pos == 1) { 68077b14db5SEric W. Biederman if (filldir(dirent, "..", 2, filp->f_pos, 68177b14db5SEric W. Biederman parent_ino(dentry), DT_DIR) < 0) 68277b14db5SEric W. Biederman goto out; 68377b14db5SEric W. Biederman filp->f_pos++; 68477b14db5SEric W. Biederman } 68577b14db5SEric W. Biederman pos = 2; 68677b14db5SEric W. Biederman 6877ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 6886a75ce16SEric W. Biederman ret = scan(h, entry, &pos, filp, dirent, filldir); 6899043476fSAl Viro if (ret) { 6909043476fSAl Viro sysctl_head_finish(h); 6919043476fSAl Viro break; 69277b14db5SEric W. Biederman } 69377b14db5SEric W. Biederman } 69477b14db5SEric W. Biederman ret = 1; 69577b14db5SEric W. Biederman out: 69677b14db5SEric W. Biederman sysctl_head_finish(head); 69777b14db5SEric W. Biederman return ret; 69877b14db5SEric W. Biederman } 69977b14db5SEric W. Biederman 70010556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 70177b14db5SEric W. Biederman { 70277b14db5SEric W. Biederman /* 70377b14db5SEric W. Biederman * sysctl entries that are not writeable, 70477b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 70577b14db5SEric W. Biederman */ 706f696a365SMiklos Szeredi struct ctl_table_header *head; 707f696a365SMiklos Szeredi struct ctl_table *table; 70877b14db5SEric W. Biederman int error; 70977b14db5SEric W. Biederman 710f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 711f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 712f696a365SMiklos Szeredi return -EACCES; 713f696a365SMiklos Szeredi 714f696a365SMiklos Szeredi head = grab_header(inode); 7159043476fSAl Viro if (IS_ERR(head)) 7169043476fSAl Viro return PTR_ERR(head); 71777b14db5SEric W. Biederman 718f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 7199043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 7209043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 7219043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 72273f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 7239043476fSAl Viro 72477b14db5SEric W. Biederman sysctl_head_finish(head); 72577b14db5SEric W. Biederman return error; 72677b14db5SEric W. Biederman } 72777b14db5SEric W. Biederman 72877b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 72977b14db5SEric W. Biederman { 73077b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 73177b14db5SEric W. Biederman int error; 73277b14db5SEric W. Biederman 73377b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 73477b14db5SEric W. Biederman return -EPERM; 73577b14db5SEric W. Biederman 73677b14db5SEric W. Biederman error = inode_change_ok(inode, attr); 7371025774cSChristoph Hellwig if (error) 73877b14db5SEric W. Biederman return error; 7391025774cSChristoph Hellwig 7401025774cSChristoph Hellwig setattr_copy(inode, attr); 7411025774cSChristoph Hellwig mark_inode_dirty(inode); 7421025774cSChristoph Hellwig return 0; 74377b14db5SEric W. Biederman } 74477b14db5SEric W. Biederman 7459043476fSAl Viro static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 7469043476fSAl Viro { 7479043476fSAl Viro struct inode *inode = dentry->d_inode; 7489043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 7499043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 7509043476fSAl Viro 7519043476fSAl Viro if (IS_ERR(head)) 7529043476fSAl Viro return PTR_ERR(head); 7539043476fSAl Viro 7549043476fSAl Viro generic_fillattr(inode, stat); 7559043476fSAl Viro if (table) 7569043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 7579043476fSAl Viro 7589043476fSAl Viro sysctl_head_finish(head); 7599043476fSAl Viro return 0; 7609043476fSAl Viro } 7619043476fSAl Viro 76277b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 763f1ecf068SLucas De Marchi .open = proc_sys_open, 764f1ecf068SLucas De Marchi .poll = proc_sys_poll, 76577b14db5SEric W. Biederman .read = proc_sys_read, 76677b14db5SEric W. Biederman .write = proc_sys_write, 7676038f373SArnd Bergmann .llseek = default_llseek, 7689043476fSAl Viro }; 7699043476fSAl Viro 7709043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 771887df078SPavel Emelyanov .read = generic_read_dir, 77277b14db5SEric W. Biederman .readdir = proc_sys_readdir, 7733222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 77477b14db5SEric W. Biederman }; 77577b14db5SEric W. Biederman 77603a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 7779043476fSAl Viro .permission = proc_sys_permission, 7789043476fSAl Viro .setattr = proc_sys_setattr, 7799043476fSAl Viro .getattr = proc_sys_getattr, 7809043476fSAl Viro }; 7819043476fSAl Viro 7829043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 78377b14db5SEric W. Biederman .lookup = proc_sys_lookup, 78477b14db5SEric W. Biederman .permission = proc_sys_permission, 78577b14db5SEric W. Biederman .setattr = proc_sys_setattr, 7869043476fSAl Viro .getattr = proc_sys_getattr, 78777b14db5SEric W. Biederman }; 78877b14db5SEric W. Biederman 7890b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 79077b14db5SEric W. Biederman { 7910b728e19SAl Viro if (flags & LOOKUP_RCU) 79234286d66SNick Piggin return -ECHILD; 7939043476fSAl Viro return !PROC_I(dentry->d_inode)->sysctl->unregistering; 7949043476fSAl Viro } 7959043476fSAl Viro 796fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 7979043476fSAl Viro { 7989043476fSAl Viro return !!PROC_I(dentry->d_inode)->sysctl->unregistering; 7999043476fSAl Viro } 8009043476fSAl Viro 8011f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8021f87f0b5SEric W. Biederman { 8031f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8041f87f0b5SEric W. Biederman int res; 8051f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8061f87f0b5SEric W. Biederman if (p->unregistering) 8071f87f0b5SEric W. Biederman res = 0; 8081f87f0b5SEric W. Biederman else if (!set->is_seen) 8091f87f0b5SEric W. Biederman res = 1; 8101f87f0b5SEric W. Biederman else 8111f87f0b5SEric W. Biederman res = set->is_seen(set); 8121f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 8131f87f0b5SEric W. Biederman return res; 8141f87f0b5SEric W. Biederman } 8151f87f0b5SEric W. Biederman 816621e155aSNick Piggin static int proc_sys_compare(const struct dentry *parent, 817621e155aSNick Piggin const struct inode *pinode, 818621e155aSNick Piggin const struct dentry *dentry, const struct inode *inode, 819621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 8209043476fSAl Viro { 821dfef6dcdSAl Viro struct ctl_table_header *head; 82231e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 82331e6b01fSNick Piggin * that inode here can be NULL */ 824dfef6dcdSAl Viro /* AV: can it, indeed? */ 82531e6b01fSNick Piggin if (!inode) 826dfef6dcdSAl Viro return 1; 827621e155aSNick Piggin if (name->len != len) 8289043476fSAl Viro return 1; 829621e155aSNick Piggin if (memcmp(name->name, str, len)) 8309043476fSAl Viro return 1; 831dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 832dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 83377b14db5SEric W. Biederman } 83477b14db5SEric W. Biederman 835d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 83677b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 8379043476fSAl Viro .d_delete = proc_sys_delete, 8389043476fSAl Viro .d_compare = proc_sys_compare, 83977b14db5SEric W. Biederman }; 84077b14db5SEric W. Biederman 8410e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 8427ec66d06SEric W. Biederman const char *name, int namelen) 8431f87f0b5SEric W. Biederman { 8447ec66d06SEric W. Biederman struct ctl_table_header *head; 8457ec66d06SEric W. Biederman struct ctl_table *entry; 8461f87f0b5SEric W. Biederman 8470e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 8487ec66d06SEric W. Biederman if (!entry) 8497ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 85051f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 8517ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 85251f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 8531f87f0b5SEric W. Biederman } 8541f87f0b5SEric W. Biederman 8557ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 8567ec66d06SEric W. Biederman const char *name, int namelen) 8571f87f0b5SEric W. Biederman { 8587ec66d06SEric W. Biederman struct ctl_table *table; 8597ec66d06SEric W. Biederman struct ctl_dir *new; 860ac13ac6fSEric W. Biederman struct ctl_node *node; 8617ec66d06SEric W. Biederman char *new_name; 8621f87f0b5SEric W. Biederman 863ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 864ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 865ac13ac6fSEric W. Biederman GFP_KERNEL); 8667ec66d06SEric W. Biederman if (!new) 8677ec66d06SEric W. Biederman return NULL; 8687ec66d06SEric W. Biederman 869ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 870ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 8717ec66d06SEric W. Biederman new_name = (char *)(table + 2); 8727ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 8737ec66d06SEric W. Biederman new_name[namelen] = '\0'; 8747ec66d06SEric W. Biederman table[0].procname = new_name; 8757ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 876ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 8777ec66d06SEric W. Biederman 8787ec66d06SEric W. Biederman return new; 8791f87f0b5SEric W. Biederman } 8801f87f0b5SEric W. Biederman 88160f126d9SEric W. Biederman /** 88260f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 88360f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 88460f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 88560f126d9SEric W. Biederman * @namelen: The length of name 88660f126d9SEric W. Biederman * 88760f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 88860f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 88960f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 89060f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 89160f126d9SEric W. Biederman * simply dropped. 89260f126d9SEric W. Biederman */ 8930e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 8940e47c99dSEric W. Biederman const char *name, int namelen) 8957ec66d06SEric W. Biederman { 8960e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 8977ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 8980eb97f38SEric W. Biederman int err; 8997ec66d06SEric W. Biederman 9007ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9010e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9027ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9037ec66d06SEric W. Biederman goto found; 9047ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9057ec66d06SEric W. Biederman goto failed; 9067ec66d06SEric W. Biederman 9077ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9087ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 9097ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9107ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 9117ec66d06SEric W. Biederman if (!new) 9127ec66d06SEric W. Biederman goto failed; 9137ec66d06SEric W. Biederman 91460f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 9150e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9167ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9177ec66d06SEric W. Biederman goto found; 9187ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9197ec66d06SEric W. Biederman goto failed; 9207ec66d06SEric W. Biederman 92160f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 9220eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 9230eb97f38SEric W. Biederman subdir = ERR_PTR(err); 9240eb97f38SEric W. Biederman if (err) 9250e47c99dSEric W. Biederman goto failed; 9267ec66d06SEric W. Biederman subdir = new; 9277ec66d06SEric W. Biederman found: 9287ec66d06SEric W. Biederman subdir->header.nreg++; 9297ec66d06SEric W. Biederman failed: 9307ec66d06SEric W. Biederman if (unlikely(IS_ERR(subdir))) { 93187ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 9326980128fSEric W. Biederman sysctl_print_dir(dir); 93387ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 9347ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 9351f87f0b5SEric W. Biederman } 9367ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 9377ec66d06SEric W. Biederman if (new) 9387ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 9397ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9407ec66d06SEric W. Biederman return subdir; 9411f87f0b5SEric W. Biederman } 9421f87f0b5SEric W. Biederman 9430e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 9440e47c99dSEric W. Biederman { 9450e47c99dSEric W. Biederman struct ctl_dir *parent; 9460e47c99dSEric W. Biederman const char *procname; 9470e47c99dSEric W. Biederman if (!dir->header.parent) 9480e47c99dSEric W. Biederman return &set->dir; 9490e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 9500e47c99dSEric W. Biederman if (IS_ERR(parent)) 9510e47c99dSEric W. Biederman return parent; 9520e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 9530e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 9540e47c99dSEric W. Biederman } 9550e47c99dSEric W. Biederman 9560e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 9570e47c99dSEric W. Biederman struct ctl_table **pentry, struct nsproxy *namespaces) 9580e47c99dSEric W. Biederman { 9590e47c99dSEric W. Biederman struct ctl_table_header *head; 9600e47c99dSEric W. Biederman struct ctl_table_root *root; 9610e47c99dSEric W. Biederman struct ctl_table_set *set; 9620e47c99dSEric W. Biederman struct ctl_table *entry; 9630e47c99dSEric W. Biederman struct ctl_dir *dir; 9640e47c99dSEric W. Biederman int ret; 9650e47c99dSEric W. Biederman 9660e47c99dSEric W. Biederman ret = 0; 9670e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 9680e47c99dSEric W. Biederman root = (*pentry)->data; 9690e47c99dSEric W. Biederman set = lookup_header_set(root, namespaces); 9700e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 9710e47c99dSEric W. Biederman if (IS_ERR(dir)) 9720e47c99dSEric W. Biederman ret = PTR_ERR(dir); 9730e47c99dSEric W. Biederman else { 9740e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 9750e47c99dSEric W. Biederman head = NULL; 9760e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 9770e47c99dSEric W. Biederman ret = -ENOENT; 9780e47c99dSEric W. Biederman if (entry && use_table(head)) { 9790e47c99dSEric W. Biederman unuse_table(*phead); 9800e47c99dSEric W. Biederman *phead = head; 9810e47c99dSEric W. Biederman *pentry = entry; 9820e47c99dSEric W. Biederman ret = 0; 9830e47c99dSEric W. Biederman } 9840e47c99dSEric W. Biederman } 9850e47c99dSEric W. Biederman 9860e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 9870e47c99dSEric W. Biederman return ret; 9880e47c99dSEric W. Biederman } 9890e47c99dSEric W. Biederman 9907c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 9917c60c48fSEric W. Biederman { 9927c60c48fSEric W. Biederman struct va_format vaf; 9937c60c48fSEric W. Biederman va_list args; 9947c60c48fSEric W. Biederman 9957c60c48fSEric W. Biederman va_start(args, fmt); 9967c60c48fSEric W. Biederman vaf.fmt = fmt; 9977c60c48fSEric W. Biederman vaf.va = &args; 9987c60c48fSEric W. Biederman 99987ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10007c60c48fSEric W. Biederman path, table->procname, &vaf); 10017c60c48fSEric W. Biederman 10027c60c48fSEric W. Biederman va_end(args); 10037c60c48fSEric W. Biederman return -EINVAL; 10047c60c48fSEric W. Biederman } 10057c60c48fSEric W. Biederman 10067c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 10077c60c48fSEric W. Biederman { 10087c60c48fSEric W. Biederman int err = 0; 10097c60c48fSEric W. Biederman for (; table->procname; table++) { 10107c60c48fSEric W. Biederman if (table->child) 10117c60c48fSEric W. Biederman err = sysctl_err(path, table, "Not a file"); 10127c60c48fSEric W. Biederman 10131f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 10141f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 10151f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 10161f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 10171f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 10181f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 10191f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 10201f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 10211f87f0b5SEric W. Biederman if (!table->data) 10227c60c48fSEric W. Biederman err = sysctl_err(path, table, "No data"); 10231f87f0b5SEric W. Biederman if (!table->maxlen) 10247c60c48fSEric W. Biederman err = sysctl_err(path, table, "No maxlen"); 10251f87f0b5SEric W. Biederman } 10261f87f0b5SEric W. Biederman if (!table->proc_handler) 10277c60c48fSEric W. Biederman err = sysctl_err(path, table, "No proc_handler"); 10287c60c48fSEric W. Biederman 10297c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 10307c60c48fSEric W. Biederman err = sysctl_err(path, table, "bogus .mode 0%o", 10317c60c48fSEric W. Biederman table->mode); 10321f87f0b5SEric W. Biederman } 10337c60c48fSEric W. Biederman return err; 10341f87f0b5SEric W. Biederman } 10351f87f0b5SEric W. Biederman 10360e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 10370e47c99dSEric W. Biederman struct ctl_table_root *link_root) 10380e47c99dSEric W. Biederman { 10390e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 10400e47c99dSEric W. Biederman struct ctl_table_header *links; 1041ac13ac6fSEric W. Biederman struct ctl_node *node; 10420e47c99dSEric W. Biederman char *link_name; 10430e47c99dSEric W. Biederman int nr_entries, name_bytes; 10440e47c99dSEric W. Biederman 10450e47c99dSEric W. Biederman name_bytes = 0; 10460e47c99dSEric W. Biederman nr_entries = 0; 10470e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 10480e47c99dSEric W. Biederman nr_entries++; 10490e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 10500e47c99dSEric W. Biederman } 10510e47c99dSEric W. Biederman 10520e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1053ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 10540e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 10550e47c99dSEric W. Biederman name_bytes, 10560e47c99dSEric W. Biederman GFP_KERNEL); 10570e47c99dSEric W. Biederman 10580e47c99dSEric W. Biederman if (!links) 10590e47c99dSEric W. Biederman return NULL; 10600e47c99dSEric W. Biederman 1061ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1062ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 10630e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 10640e47c99dSEric W. Biederman 10650e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 10660e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 10670e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 10680e47c99dSEric W. Biederman link->procname = link_name; 10690e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 10700e47c99dSEric W. Biederman link->data = link_root; 10710e47c99dSEric W. Biederman link_name += len; 10720e47c99dSEric W. Biederman } 1073ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 10740e47c99dSEric W. Biederman links->nreg = nr_entries; 10750e47c99dSEric W. Biederman 10760e47c99dSEric W. Biederman return links; 10770e47c99dSEric W. Biederman } 10780e47c99dSEric W. Biederman 10790e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 10800e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 10810e47c99dSEric W. Biederman { 10820e47c99dSEric W. Biederman struct ctl_table_header *head; 10830e47c99dSEric W. Biederman struct ctl_table *entry, *link; 10840e47c99dSEric W. Biederman 10850e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 10860e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 10870e47c99dSEric W. Biederman const char *procname = entry->procname; 10880e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 10890e47c99dSEric W. Biederman if (!link) 10900e47c99dSEric W. Biederman return false; 10910e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 10920e47c99dSEric W. Biederman continue; 10930e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 10940e47c99dSEric W. Biederman continue; 10950e47c99dSEric W. Biederman return false; 10960e47c99dSEric W. Biederman } 10970e47c99dSEric W. Biederman 10980e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 10990e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11000e47c99dSEric W. Biederman const char *procname = entry->procname; 11010e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11020e47c99dSEric W. Biederman head->nreg++; 11030e47c99dSEric W. Biederman } 11040e47c99dSEric W. Biederman return true; 11050e47c99dSEric W. Biederman } 11060e47c99dSEric W. Biederman 11070e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 11080e47c99dSEric W. Biederman { 11090e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 11100e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 11110e47c99dSEric W. Biederman struct ctl_table_header *links; 11120e47c99dSEric W. Biederman int err; 11130e47c99dSEric W. Biederman 11140e47c99dSEric W. Biederman if (head->set == root_set) 11150e47c99dSEric W. Biederman return 0; 11160e47c99dSEric W. Biederman 11170e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 11180e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 11190e47c99dSEric W. Biederman return 0; 11200e47c99dSEric W. Biederman 11210e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 11220e47c99dSEric W. Biederman return 0; 11230e47c99dSEric W. Biederman 11240e47c99dSEric W. Biederman core_parent->header.nreg++; 11250e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 11260e47c99dSEric W. Biederman 11270e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 11280e47c99dSEric W. Biederman 11290e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 11300e47c99dSEric W. Biederman err = -ENOMEM; 11310e47c99dSEric W. Biederman if (!links) 11320e47c99dSEric W. Biederman goto out; 11330e47c99dSEric W. Biederman 11340e47c99dSEric W. Biederman err = 0; 11350e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 11360e47c99dSEric W. Biederman kfree(links); 11370e47c99dSEric W. Biederman goto out; 11380e47c99dSEric W. Biederman } 11390e47c99dSEric W. Biederman 11400e47c99dSEric W. Biederman err = insert_header(core_parent, links); 11410e47c99dSEric W. Biederman if (err) 11420e47c99dSEric W. Biederman kfree(links); 11430e47c99dSEric W. Biederman out: 11440e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 11450e47c99dSEric W. Biederman return err; 11460e47c99dSEric W. Biederman } 11470e47c99dSEric W. Biederman 11481f87f0b5SEric W. Biederman /** 1149f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 115060a47a2eSEric W. Biederman * @set: Sysctl tree to register on 11511f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 11521f87f0b5SEric W. Biederman * @table: the top-level table structure 11531f87f0b5SEric W. Biederman * 11541f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 11551f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 11561f87f0b5SEric W. Biederman * 11571f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 11581f87f0b5SEric W. Biederman * 11591f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 11601f87f0b5SEric W. Biederman * enter a sysctl file 11611f87f0b5SEric W. Biederman * 11621f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 11631f87f0b5SEric W. Biederman * 11641f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 11651f87f0b5SEric W. Biederman * 1166f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 11671f87f0b5SEric W. Biederman * 1168f728019bSEric W. Biederman * child - must be %NULL. 11691f87f0b5SEric W. Biederman * 11701f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 11711f87f0b5SEric W. Biederman * 11721f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 11731f87f0b5SEric W. Biederman * 11741f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 11751f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 11761f87f0b5SEric W. Biederman * 1177f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1178f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 11791f87f0b5SEric W. Biederman * 11801f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 11811f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 11821f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 11831f87f0b5SEric W. Biederman * 11841f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 11851f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 11861f87f0b5SEric W. Biederman * 11871f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 11881f87f0b5SEric W. Biederman * to the table header on success. 11891f87f0b5SEric W. Biederman */ 11906e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 119160a47a2eSEric W. Biederman struct ctl_table_set *set, 11926e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 11931f87f0b5SEric W. Biederman { 119460a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 11951f87f0b5SEric W. Biederman struct ctl_table_header *header; 11966e9d5164SEric W. Biederman const char *name, *nextname; 11977ec66d06SEric W. Biederman struct ctl_dir *dir; 1198ac13ac6fSEric W. Biederman struct ctl_table *entry; 1199ac13ac6fSEric W. Biederman struct ctl_node *node; 1200ac13ac6fSEric W. Biederman int nr_entries = 0; 12011f87f0b5SEric W. Biederman 1202ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1203ac13ac6fSEric W. Biederman nr_entries++; 1204ac13ac6fSEric W. Biederman 1205ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1206ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 12071f87f0b5SEric W. Biederman if (!header) 12081f87f0b5SEric W. Biederman return NULL; 12091f87f0b5SEric W. Biederman 1210ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1211ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 12127c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 12137c60c48fSEric W. Biederman goto fail; 12148d6ecfccSEric W. Biederman 12151f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 12160e47c99dSEric W. Biederman dir = &set->dir; 121760f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 12187ec66d06SEric W. Biederman dir->header.nreg++; 12197ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 12207ec66d06SEric W. Biederman 12217ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 12227ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 12237ec66d06SEric W. Biederman int namelen; 12247ec66d06SEric W. Biederman nextname = strchr(name, '/'); 12257ec66d06SEric W. Biederman if (nextname) { 12267ec66d06SEric W. Biederman namelen = nextname - name; 12277ec66d06SEric W. Biederman nextname++; 12287ec66d06SEric W. Biederman } else { 12297ec66d06SEric W. Biederman namelen = strlen(name); 12307ec66d06SEric W. Biederman } 12317ec66d06SEric W. Biederman if (namelen == 0) 12321f87f0b5SEric W. Biederman continue; 12337ec66d06SEric W. Biederman 12340e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 12357ec66d06SEric W. Biederman if (IS_ERR(dir)) 12367ec66d06SEric W. Biederman goto fail; 12371f87f0b5SEric W. Biederman } 12380e47c99dSEric W. Biederman 12397ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 12400e47c99dSEric W. Biederman if (insert_header(dir, header)) 12410e47c99dSEric W. Biederman goto fail_put_dir_locked; 12420e47c99dSEric W. Biederman 12437ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 12441f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 12451f87f0b5SEric W. Biederman 12461f87f0b5SEric W. Biederman return header; 12470e47c99dSEric W. Biederman 12487ec66d06SEric W. Biederman fail_put_dir_locked: 12497ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 12507c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 12517c60c48fSEric W. Biederman fail: 12527c60c48fSEric W. Biederman kfree(header); 12537c60c48fSEric W. Biederman dump_stack(); 12547c60c48fSEric W. Biederman return NULL; 12551f87f0b5SEric W. Biederman } 12561f87f0b5SEric W. Biederman 1257fea478d4SEric W. Biederman /** 1258fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1259fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1260fea478d4SEric W. Biederman * @table: the table structure 1261fea478d4SEric W. Biederman * 1262fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1263fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1264fea478d4SEric W. Biederman * 1265fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1266fea478d4SEric W. Biederman */ 1267fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1268fea478d4SEric W. Biederman { 1269fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1270fea478d4SEric W. Biederman path, table); 1271fea478d4SEric W. Biederman } 1272fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1273fea478d4SEric W. Biederman 12746e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 12756e9d5164SEric W. Biederman { 12766e9d5164SEric W. Biederman int namelen; 12776e9d5164SEric W. Biederman namelen = strlen(name); 12786e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 12796e9d5164SEric W. Biederman return NULL; 12806e9d5164SEric W. Biederman memcpy(pos, name, namelen); 12816e9d5164SEric W. Biederman pos[namelen] = '/'; 12826e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 12836e9d5164SEric W. Biederman pos += namelen + 1; 12846e9d5164SEric W. Biederman return pos; 12856e9d5164SEric W. Biederman } 12866e9d5164SEric W. Biederman 1287f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1288f728019bSEric W. Biederman { 1289f728019bSEric W. Biederman int has_files = 0; 1290f728019bSEric W. Biederman int nr_subheaders = 0; 1291f728019bSEric W. Biederman struct ctl_table *entry; 1292f728019bSEric W. Biederman 1293f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1294f728019bSEric W. Biederman if (!table || !table->procname) 1295f728019bSEric W. Biederman return 1; 1296f728019bSEric W. Biederman 1297f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1298f728019bSEric W. Biederman if (entry->child) 1299f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1300f728019bSEric W. Biederman else 1301f728019bSEric W. Biederman has_files = 1; 1302f728019bSEric W. Biederman } 1303f728019bSEric W. Biederman return nr_subheaders + has_files; 1304f728019bSEric W. Biederman } 1305f728019bSEric W. Biederman 1306f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 130760a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1308f728019bSEric W. Biederman struct ctl_table *table) 1309f728019bSEric W. Biederman { 1310f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1311f728019bSEric W. Biederman struct ctl_table *entry, *files; 1312f728019bSEric W. Biederman int nr_files = 0; 1313f728019bSEric W. Biederman int nr_dirs = 0; 1314f728019bSEric W. Biederman int err = -ENOMEM; 1315f728019bSEric W. Biederman 1316f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1317f728019bSEric W. Biederman if (entry->child) 1318f728019bSEric W. Biederman nr_dirs++; 1319f728019bSEric W. Biederman else 1320f728019bSEric W. Biederman nr_files++; 1321f728019bSEric W. Biederman } 1322f728019bSEric W. Biederman 1323f728019bSEric W. Biederman files = table; 1324f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1325f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1326f728019bSEric W. Biederman struct ctl_table *new; 1327f728019bSEric W. Biederman files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), 1328f728019bSEric W. Biederman GFP_KERNEL); 1329f728019bSEric W. Biederman if (!files) 1330f728019bSEric W. Biederman goto out; 1331f728019bSEric W. Biederman 1332f728019bSEric W. Biederman ctl_table_arg = files; 1333f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1334f728019bSEric W. Biederman if (entry->child) 1335f728019bSEric W. Biederman continue; 1336f728019bSEric W. Biederman *new = *entry; 1337f728019bSEric W. Biederman new++; 1338f728019bSEric W. Biederman } 1339f728019bSEric W. Biederman } 1340f728019bSEric W. Biederman 1341f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1342f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1343f728019bSEric W. Biederman struct ctl_table_header *header; 134460a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1345f728019bSEric W. Biederman if (!header) { 1346f728019bSEric W. Biederman kfree(ctl_table_arg); 1347f728019bSEric W. Biederman goto out; 1348f728019bSEric W. Biederman } 1349f728019bSEric W. Biederman 1350f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1351f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1352f728019bSEric W. Biederman **subheader = header; 1353f728019bSEric W. Biederman (*subheader)++; 1354f728019bSEric W. Biederman } 1355f728019bSEric W. Biederman 1356f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1357f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1358f728019bSEric W. Biederman char *child_pos; 1359f728019bSEric W. Biederman 1360f728019bSEric W. Biederman if (!entry->child) 1361f728019bSEric W. Biederman continue; 1362f728019bSEric W. Biederman 1363f728019bSEric W. Biederman err = -ENAMETOOLONG; 1364f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1365f728019bSEric W. Biederman if (!child_pos) 1366f728019bSEric W. Biederman goto out; 1367f728019bSEric W. Biederman 1368f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 136960a47a2eSEric W. Biederman set, entry->child); 1370f728019bSEric W. Biederman pos[0] = '\0'; 1371f728019bSEric W. Biederman if (err) 1372f728019bSEric W. Biederman goto out; 1373f728019bSEric W. Biederman } 1374f728019bSEric W. Biederman err = 0; 1375f728019bSEric W. Biederman out: 1376f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1377f728019bSEric W. Biederman return err; 1378f728019bSEric W. Biederman } 1379f728019bSEric W. Biederman 13806e9d5164SEric W. Biederman /** 13816e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 138260a47a2eSEric W. Biederman * @set: Sysctl tree to register on 13836e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 13846e9d5164SEric W. Biederman * @table: the top-level table structure 13856e9d5164SEric W. Biederman * 13866e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 13876e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 13886e9d5164SEric W. Biederman * 13896e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 13906e9d5164SEric W. Biederman */ 13916e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 139260a47a2eSEric W. Biederman struct ctl_table_set *set, 13936e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 13946e9d5164SEric W. Biederman { 1395ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1396f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1397f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 13986e9d5164SEric W. Biederman const struct ctl_path *component; 13996e9d5164SEric W. Biederman char *new_path, *pos; 14006e9d5164SEric W. Biederman 14016e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 14026e9d5164SEric W. Biederman if (!new_path) 14036e9d5164SEric W. Biederman return NULL; 14046e9d5164SEric W. Biederman 14056e9d5164SEric W. Biederman pos[0] = '\0'; 14066e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 14076e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 14086e9d5164SEric W. Biederman if (!pos) 14096e9d5164SEric W. Biederman goto out; 14106e9d5164SEric W. Biederman } 1411ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1412ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1413ec6a5266SEric W. Biederman if (!pos) 1414ec6a5266SEric W. Biederman goto out; 1415ec6a5266SEric W. Biederman table = table->child; 1416ec6a5266SEric W. Biederman } 1417f728019bSEric W. Biederman if (nr_subheaders == 1) { 141860a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1419ec6a5266SEric W. Biederman if (header) 1420ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1421f728019bSEric W. Biederman } else { 1422f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1423f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1424f728019bSEric W. Biederman if (!header) 1425f728019bSEric W. Biederman goto out; 1426f728019bSEric W. Biederman 1427f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1428f728019bSEric W. Biederman subheader = subheaders; 1429f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1430f728019bSEric W. Biederman 1431f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 143260a47a2eSEric W. Biederman set, table)) 1433f728019bSEric W. Biederman goto err_register_leaves; 1434f728019bSEric W. Biederman } 1435f728019bSEric W. Biederman 14366e9d5164SEric W. Biederman out: 14376e9d5164SEric W. Biederman kfree(new_path); 14386e9d5164SEric W. Biederman return header; 1439f728019bSEric W. Biederman 1440f728019bSEric W. Biederman err_register_leaves: 1441f728019bSEric W. Biederman while (subheader > subheaders) { 1442f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1443f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1444f728019bSEric W. Biederman unregister_sysctl_table(subh); 1445f728019bSEric W. Biederman kfree(table); 1446f728019bSEric W. Biederman } 1447f728019bSEric W. Biederman kfree(header); 1448f728019bSEric W. Biederman header = NULL; 1449f728019bSEric W. Biederman goto out; 14506e9d5164SEric W. Biederman } 14516e9d5164SEric W. Biederman 14521f87f0b5SEric W. Biederman /** 14531f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 14541f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14551f87f0b5SEric W. Biederman * @table: the top-level table structure 14561f87f0b5SEric W. Biederman * 14571f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14581f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14591f87f0b5SEric W. Biederman * 14601f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 14611f87f0b5SEric W. Biederman */ 14621f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 14631f87f0b5SEric W. Biederman struct ctl_table *table) 14641f87f0b5SEric W. Biederman { 146560a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 14661f87f0b5SEric W. Biederman path, table); 14671f87f0b5SEric W. Biederman } 14681f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 14691f87f0b5SEric W. Biederman 14701f87f0b5SEric W. Biederman /** 14711f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 14721f87f0b5SEric W. Biederman * @table: the top-level table structure 14731f87f0b5SEric W. Biederman * 14741f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14751f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14761f87f0b5SEric W. Biederman * 14771f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 14781f87f0b5SEric W. Biederman */ 14791f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 14801f87f0b5SEric W. Biederman { 14811f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 14821f87f0b5SEric W. Biederman 14831f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 14841f87f0b5SEric W. Biederman } 14851f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 14861f87f0b5SEric W. Biederman 14870e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 14880e47c99dSEric W. Biederman { 14890e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 14900e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 14910e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 14920e47c99dSEric W. Biederman struct ctl_dir *core_parent; 14930e47c99dSEric W. Biederman struct ctl_table *entry; 14940e47c99dSEric W. Biederman 14950e47c99dSEric W. Biederman if (header->set == root_set) 14960e47c99dSEric W. Biederman return; 14970e47c99dSEric W. Biederman 14980e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 14990e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 15000e47c99dSEric W. Biederman return; 15010e47c99dSEric W. Biederman 15020e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 15030e47c99dSEric W. Biederman struct ctl_table_header *link_head; 15040e47c99dSEric W. Biederman struct ctl_table *link; 15050e47c99dSEric W. Biederman const char *name = entry->procname; 15060e47c99dSEric W. Biederman 15070e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 15080e47c99dSEric W. Biederman if (link && 15090e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 15100e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 15110e47c99dSEric W. Biederman drop_sysctl_table(link_head); 15120e47c99dSEric W. Biederman } 15130e47c99dSEric W. Biederman else { 151487ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 15150e47c99dSEric W. Biederman sysctl_print_dir(parent); 151687ebdc00SAndrew Morton pr_cont("/%s\n", name); 15170e47c99dSEric W. Biederman } 15180e47c99dSEric W. Biederman } 15190e47c99dSEric W. Biederman } 15200e47c99dSEric W. Biederman 1521938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1522938aaa4fSEric W. Biederman { 15237ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 15247ec66d06SEric W. Biederman 1525938aaa4fSEric W. Biederman if (--header->nreg) 1526938aaa4fSEric W. Biederman return; 1527938aaa4fSEric W. Biederman 15280e47c99dSEric W. Biederman put_links(header); 1529938aaa4fSEric W. Biederman start_unregistering(header); 1530938aaa4fSEric W. Biederman if (!--header->count) 1531938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 15327ec66d06SEric W. Biederman 15337ec66d06SEric W. Biederman if (parent) 15347ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1535938aaa4fSEric W. Biederman } 1536938aaa4fSEric W. Biederman 15371f87f0b5SEric W. Biederman /** 15381f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 15391f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 15401f87f0b5SEric W. Biederman * 15411f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 15421f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 15431f87f0b5SEric W. Biederman */ 15441f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 15451f87f0b5SEric W. Biederman { 1546f728019bSEric W. Biederman int nr_subheaders; 15471f87f0b5SEric W. Biederman might_sleep(); 15481f87f0b5SEric W. Biederman 15491f87f0b5SEric W. Biederman if (header == NULL) 15501f87f0b5SEric W. Biederman return; 15511f87f0b5SEric W. Biederman 1552f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1553f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1554f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1555f728019bSEric W. Biederman int i; 1556f728019bSEric W. Biederman 1557f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1558f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1559f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1560f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1561f728019bSEric W. Biederman unregister_sysctl_table(subh); 1562f728019bSEric W. Biederman kfree(table); 1563f728019bSEric W. Biederman } 1564f728019bSEric W. Biederman kfree(header); 1565f728019bSEric W. Biederman return; 1566f728019bSEric W. Biederman } 1567f728019bSEric W. Biederman 15681f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1569938aaa4fSEric W. Biederman drop_sysctl_table(header); 15701f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 15711f87f0b5SEric W. Biederman } 15721f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 15731f87f0b5SEric W. Biederman 15740e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 15759eb47c26SEric W. Biederman struct ctl_table_root *root, 15761f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 15771f87f0b5SEric W. Biederman { 15781347440dSDan Carpenter memset(set, 0, sizeof(*set)); 15790e47c99dSEric W. Biederman set->is_seen = is_seen; 1580ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 15811f87f0b5SEric W. Biederman } 15821f87f0b5SEric W. Biederman 158397324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 158497324cd8SEric W. Biederman { 1585ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 158697324cd8SEric W. Biederman } 15871f87f0b5SEric W. Biederman 15881e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 158977b14db5SEric W. Biederman { 1590e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1591e1675231SAlexey Dobriyan 159277b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 15939043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 15949043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 159577b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1596de4e83bdSEric W. Biederman 1597de4e83bdSEric W. Biederman return sysctl_init(); 159877b14db5SEric W. Biederman } 1599