1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 277b14db5SEric W. Biederman /* 377b14db5SEric W. Biederman * /proc/sys support 477b14db5SEric W. Biederman */ 51e0edd3fSAlexey Dobriyan #include <linux/init.h> 677b14db5SEric W. Biederman #include <linux/sysctl.h> 7f1ecf068SLucas De Marchi #include <linux/poll.h> 877b14db5SEric W. Biederman #include <linux/proc_fs.h> 987ebdc00SAndrew Morton #include <linux/printk.h> 1077b14db5SEric W. Biederman #include <linux/security.h> 1140401530SAl Viro #include <linux/sched.h> 125b825c3aSIngo Molnar #include <linux/cred.h> 1334286d66SNick Piggin #include <linux/namei.h> 1440401530SAl Viro #include <linux/mm.h> 151f87f0b5SEric W. Biederman #include <linux/module.h> 167b146cebSAndrey Ignatov #include <linux/bpf-cgroup.h> 1777b14db5SEric W. Biederman #include "internal.h" 1877b14db5SEric W. Biederman 19d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 2077b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 2103a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 229043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 239043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 2477b14db5SEric W. Biederman 25f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 26f9bd6733SEric W. Biederman 27f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 28f9bd6733SEric W. Biederman { } 29f9bd6733SEric W. Biederman }; 30f9bd6733SEric W. Biederman 31f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 32f9bd6733SEric W. Biederman { 33f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 34f9bd6733SEric W. Biederman } 35f9bd6733SEric W. Biederman 36f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 37f9bd6733SEric W. Biederman { 38f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 39f9bd6733SEric W. Biederman } 40f9bd6733SEric W. Biederman 41f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 42f9bd6733SEric W. Biederman 43f9bd6733SEric W. Biederman { 44f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 45f9bd6733SEric W. Biederman } 46f9bd6733SEric W. Biederman 47f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 48f1ecf068SLucas De Marchi { 49f1ecf068SLucas De Marchi if (!poll) 50f1ecf068SLucas De Marchi return; 51f1ecf068SLucas De Marchi 52f1ecf068SLucas De Marchi atomic_inc(&poll->event); 53f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 54f1ecf068SLucas De Marchi } 55f1ecf068SLucas De Marchi 56a194558eSEric W. Biederman static struct ctl_table root_table[] = { 57a194558eSEric W. Biederman { 58a194558eSEric W. Biederman .procname = "", 597ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 60a194558eSEric W. Biederman }, 61a194558eSEric W. Biederman { } 62a194558eSEric W. Biederman }; 630e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 640e47c99dSEric W. Biederman .default_set.dir.header = { 651f87f0b5SEric W. Biederman {{.count = 1, 66938aaa4fSEric W. Biederman .nreg = 1, 67ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 680e47c99dSEric W. Biederman .ctl_table_arg = root_table, 691f87f0b5SEric W. Biederman .root = &sysctl_table_root, 701f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 717ec66d06SEric W. Biederman }, 721f87f0b5SEric W. Biederman }; 731f87f0b5SEric W. Biederman 741f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 751f87f0b5SEric W. Biederman 767ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 770e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 7813bcc6a2SEric W. Biederman struct ctl_table **pentry); 790e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 800e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 817ec66d06SEric W. Biederman 826980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 836980128fSEric W. Biederman { 846980128fSEric W. Biederman if (dir->header.parent) 856980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 8687ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 876980128fSEric W. Biederman } 886980128fSEric W. Biederman 89076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 90076c3eedSEric W. Biederman { 91076c3eedSEric W. Biederman int minlen; 92076c3eedSEric W. Biederman int cmp; 93076c3eedSEric W. Biederman 94076c3eedSEric W. Biederman minlen = len1; 95076c3eedSEric W. Biederman if (minlen > len2) 96076c3eedSEric W. Biederman minlen = len2; 97076c3eedSEric W. Biederman 98076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 99076c3eedSEric W. Biederman if (cmp == 0) 100076c3eedSEric W. Biederman cmp = len1 - len2; 101076c3eedSEric W. Biederman return cmp; 102076c3eedSEric W. Biederman } 103076c3eedSEric W. Biederman 10460f126d9SEric W. Biederman /* Called under sysctl_lock */ 105076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1060e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 107076c3eedSEric W. Biederman { 108076c3eedSEric W. Biederman struct ctl_table_header *head; 109076c3eedSEric W. Biederman struct ctl_table *entry; 110ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 111076c3eedSEric W. Biederman 112ac13ac6fSEric W. Biederman while (node) 113ac13ac6fSEric W. Biederman { 114ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 115ac13ac6fSEric W. Biederman const char *procname; 116ac13ac6fSEric W. Biederman int cmp; 117ac13ac6fSEric W. Biederman 118ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 119ac13ac6fSEric W. Biederman head = ctl_node->header; 120ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 121ac13ac6fSEric W. Biederman procname = entry->procname; 122ac13ac6fSEric W. Biederman 123ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 124ac13ac6fSEric W. Biederman if (cmp < 0) 125ac13ac6fSEric W. Biederman node = node->rb_left; 126ac13ac6fSEric W. Biederman else if (cmp > 0) 127ac13ac6fSEric W. Biederman node = node->rb_right; 128ac13ac6fSEric W. Biederman else { 129076c3eedSEric W. Biederman *phead = head; 130076c3eedSEric W. Biederman return entry; 131076c3eedSEric W. Biederman } 132076c3eedSEric W. Biederman } 133076c3eedSEric W. Biederman return NULL; 134076c3eedSEric W. Biederman } 135076c3eedSEric W. Biederman 136ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 137ac13ac6fSEric W. Biederman { 138ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 139ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 140ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 141ac13ac6fSEric W. Biederman const char *name = entry->procname; 142ac13ac6fSEric W. Biederman int namelen = strlen(name); 143ac13ac6fSEric W. Biederman 144ac13ac6fSEric W. Biederman while (*p) { 145ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 146ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 147ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 148ac13ac6fSEric W. Biederman const char *parent_name; 149ac13ac6fSEric W. Biederman int cmp; 150ac13ac6fSEric W. Biederman 151ac13ac6fSEric W. Biederman parent = *p; 152ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 153ac13ac6fSEric W. Biederman parent_head = parent_node->header; 154ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 155ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 156ac13ac6fSEric W. Biederman 157ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 158ac13ac6fSEric W. Biederman if (cmp < 0) 159ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 160ac13ac6fSEric W. Biederman else if (cmp > 0) 161ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 162ac13ac6fSEric W. Biederman else { 16387ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 164ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 16587ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 166ac13ac6fSEric W. Biederman return -EEXIST; 167ac13ac6fSEric W. Biederman } 168ac13ac6fSEric W. Biederman } 169ac13ac6fSEric W. Biederman 170ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 171ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 172ac13ac6fSEric W. Biederman return 0; 173ac13ac6fSEric W. Biederman } 174ac13ac6fSEric W. Biederman 175ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 176ac13ac6fSEric W. Biederman { 177ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 178ac13ac6fSEric W. Biederman 179ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 180ac13ac6fSEric W. Biederman } 181ac13ac6fSEric W. Biederman 182e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 183e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 184ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 185e0d04529SEric W. Biederman { 1867ec66d06SEric W. Biederman head->ctl_table = table; 187e0d04529SEric W. Biederman head->ctl_table_arg = table; 188e0d04529SEric W. Biederman head->used = 0; 189e0d04529SEric W. Biederman head->count = 1; 190e0d04529SEric W. Biederman head->nreg = 1; 191e0d04529SEric W. Biederman head->unregistering = NULL; 192e0d04529SEric W. Biederman head->root = root; 193e0d04529SEric W. Biederman head->set = set; 194e0d04529SEric W. Biederman head->parent = NULL; 195ac13ac6fSEric W. Biederman head->node = node; 1962fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 197ac13ac6fSEric W. Biederman if (node) { 198ac13ac6fSEric W. Biederman struct ctl_table *entry; 1994c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 200ac13ac6fSEric W. Biederman node->header = head; 201ac13ac6fSEric W. Biederman } 202ac13ac6fSEric W. Biederman } 203e0d04529SEric W. Biederman 2048425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2058425d6aaSEric W. Biederman { 206ac13ac6fSEric W. Biederman struct ctl_table *entry; 207ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 208ac13ac6fSEric W. Biederman erase_entry(head, entry); 2098425d6aaSEric W. Biederman } 2108425d6aaSEric W. Biederman 2110e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2128425d6aaSEric W. Biederman { 213ac13ac6fSEric W. Biederman struct ctl_table *entry; 2140e47c99dSEric W. Biederman int err; 2150e47c99dSEric W. Biederman 216f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 217f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 218f9bd6733SEric W. Biederman return -EROFS; 219f9bd6733SEric W. Biederman 220f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 221f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 222f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 223f9bd6733SEric W. Biederman return -EINVAL; 224f9bd6733SEric W. Biederman set_empty_dir(dir); 225f9bd6733SEric W. Biederman } 226f9bd6733SEric W. Biederman 2270e47c99dSEric W. Biederman dir->header.nreg++; 2287ec66d06SEric W. Biederman header->parent = dir; 2290e47c99dSEric W. Biederman err = insert_links(header); 2300e47c99dSEric W. Biederman if (err) 2310e47c99dSEric W. Biederman goto fail_links; 232ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 233ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 234ac13ac6fSEric W. Biederman if (err) 235ac13ac6fSEric W. Biederman goto fail; 236ac13ac6fSEric W. Biederman } 2370e47c99dSEric W. Biederman return 0; 238ac13ac6fSEric W. Biederman fail: 239ac13ac6fSEric W. Biederman erase_header(header); 240ac13ac6fSEric W. Biederman put_links(header); 2410e47c99dSEric W. Biederman fail_links: 242f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 243f9bd6733SEric W. Biederman clear_empty_dir(dir); 2440e47c99dSEric W. Biederman header->parent = NULL; 2450e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2460e47c99dSEric W. Biederman return err; 2478425d6aaSEric W. Biederman } 2488425d6aaSEric W. Biederman 2491f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2501f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2511f87f0b5SEric W. Biederman { 2521f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2531f87f0b5SEric W. Biederman return 0; 2541f87f0b5SEric W. Biederman p->used++; 2551f87f0b5SEric W. Biederman return 1; 2561f87f0b5SEric W. Biederman } 2571f87f0b5SEric W. Biederman 2581f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2591f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2601f87f0b5SEric W. Biederman { 2611f87f0b5SEric W. Biederman if (!--p->used) 2621f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2631f87f0b5SEric W. Biederman complete(p->unregistering); 2641f87f0b5SEric W. Biederman } 2651f87f0b5SEric W. Biederman 266d6cffbbeSKonstantin Khlebnikov static void proc_sys_prune_dcache(struct ctl_table_header *head) 267d6cffbbeSKonstantin Khlebnikov { 2682fd1d2c4SEric W. Biederman struct inode *inode; 269d6cffbbeSKonstantin Khlebnikov struct proc_inode *ei; 2702fd1d2c4SEric W. Biederman struct hlist_node *node; 2712fd1d2c4SEric W. Biederman struct super_block *sb; 272d6cffbbeSKonstantin Khlebnikov 273ace0c791SEric W. Biederman rcu_read_lock(); 2742fd1d2c4SEric W. Biederman for (;;) { 2752fd1d2c4SEric W. Biederman node = hlist_first_rcu(&head->inodes); 2762fd1d2c4SEric W. Biederman if (!node) 2772fd1d2c4SEric W. Biederman break; 2782fd1d2c4SEric W. Biederman ei = hlist_entry(node, struct proc_inode, sysctl_inodes); 2792fd1d2c4SEric W. Biederman spin_lock(&sysctl_lock); 2802fd1d2c4SEric W. Biederman hlist_del_init_rcu(&ei->sysctl_inodes); 2812fd1d2c4SEric W. Biederman spin_unlock(&sysctl_lock); 2822fd1d2c4SEric W. Biederman 2832fd1d2c4SEric W. Biederman inode = &ei->vfs_inode; 2842fd1d2c4SEric W. Biederman sb = inode->i_sb; 2852fd1d2c4SEric W. Biederman if (!atomic_inc_not_zero(&sb->s_active)) 2862fd1d2c4SEric W. Biederman continue; 2872fd1d2c4SEric W. Biederman inode = igrab(inode); 288ace0c791SEric W. Biederman rcu_read_unlock(); 2892fd1d2c4SEric W. Biederman if (unlikely(!inode)) { 2902fd1d2c4SEric W. Biederman deactivate_super(sb); 2912fd1d2c4SEric W. Biederman rcu_read_lock(); 2922fd1d2c4SEric W. Biederman continue; 2932fd1d2c4SEric W. Biederman } 2942fd1d2c4SEric W. Biederman 295d6cffbbeSKonstantin Khlebnikov d_prune_aliases(inode); 2962fd1d2c4SEric W. Biederman iput(inode); 2972fd1d2c4SEric W. Biederman deactivate_super(sb); 2982fd1d2c4SEric W. Biederman 299ace0c791SEric W. Biederman rcu_read_lock(); 300d6cffbbeSKonstantin Khlebnikov } 301ace0c791SEric W. Biederman rcu_read_unlock(); 302d6cffbbeSKonstantin Khlebnikov } 303d6cffbbeSKonstantin Khlebnikov 3041f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 3051f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 3061f87f0b5SEric W. Biederman { 3071f87f0b5SEric W. Biederman /* 3081f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 3091f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 3101f87f0b5SEric W. Biederman */ 3111f87f0b5SEric W. Biederman if (unlikely(p->used)) { 3121f87f0b5SEric W. Biederman struct completion wait; 3131f87f0b5SEric W. Biederman init_completion(&wait); 3141f87f0b5SEric W. Biederman p->unregistering = &wait; 3151f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3161f87f0b5SEric W. Biederman wait_for_completion(&wait); 3171f87f0b5SEric W. Biederman } else { 3181f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3191f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 320ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3211f87f0b5SEric W. Biederman } 3221f87f0b5SEric W. Biederman /* 323d6cffbbeSKonstantin Khlebnikov * Prune dentries for unregistered sysctls: namespaced sysctls 324d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 325d6cffbbeSKonstantin Khlebnikov */ 326d6cffbbeSKonstantin Khlebnikov proc_sys_prune_dcache(p); 327d6cffbbeSKonstantin Khlebnikov /* 3281f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3291f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3301f87f0b5SEric W. Biederman */ 331ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3328425d6aaSEric W. Biederman erase_header(p); 3331f87f0b5SEric W. Biederman } 3341f87f0b5SEric W. Biederman 3351f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3361f87f0b5SEric W. Biederman { 337ab4a1f24SPrasad Joshi BUG_ON(!head); 3381f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3391f87f0b5SEric W. Biederman if (!use_table(head)) 3401f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3411f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3421f87f0b5SEric W. Biederman return head; 3431f87f0b5SEric W. Biederman } 3441f87f0b5SEric W. Biederman 3451f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3461f87f0b5SEric W. Biederman { 3471f87f0b5SEric W. Biederman if (!head) 3481f87f0b5SEric W. Biederman return; 3491f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3501f87f0b5SEric W. Biederman unuse_table(head); 3511f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3521f87f0b5SEric W. Biederman } 3531f87f0b5SEric W. Biederman 3541f87f0b5SEric W. Biederman static struct ctl_table_set * 35513bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3561f87f0b5SEric W. Biederman { 3571f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3581f87f0b5SEric W. Biederman if (root->lookup) 35913bcc6a2SEric W. Biederman set = root->lookup(root); 3601f87f0b5SEric W. Biederman return set; 3611f87f0b5SEric W. Biederman } 3621f87f0b5SEric W. Biederman 363076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3647ec66d06SEric W. Biederman struct ctl_dir *dir, 365076c3eedSEric W. Biederman const char *name, int namelen) 366076c3eedSEric W. Biederman { 367076c3eedSEric W. Biederman struct ctl_table_header *head; 368076c3eedSEric W. Biederman struct ctl_table *entry; 369076c3eedSEric W. Biederman 370076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3710e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 372076c3eedSEric W. Biederman if (entry && use_table(head)) 373076c3eedSEric W. Biederman *phead = head; 374076c3eedSEric W. Biederman else 375076c3eedSEric W. Biederman entry = NULL; 376076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 377076c3eedSEric W. Biederman return entry; 378076c3eedSEric W. Biederman } 379076c3eedSEric W. Biederman 380ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3811f87f0b5SEric W. Biederman { 382ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3831f87f0b5SEric W. Biederman 384ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 385ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 386ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 387ac13ac6fSEric W. Biederman return ctl_node; 3881f87f0b5SEric W. Biederman } 3891f87f0b5SEric W. Biederman return NULL; 3901f87f0b5SEric W. Biederman } 3911f87f0b5SEric W. Biederman 3927ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3936a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3941f87f0b5SEric W. Biederman { 395ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3967ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 397ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3986a75ce16SEric W. Biederman 3996a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 400ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 4016a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 402ac13ac6fSEric W. Biederman if (ctl_node) { 403ac13ac6fSEric W. Biederman head = ctl_node->header; 404ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 405ac13ac6fSEric W. Biederman } 4066a75ce16SEric W. Biederman *phead = head; 4076a75ce16SEric W. Biederman *pentry = entry; 4086a75ce16SEric W. Biederman } 4096a75ce16SEric W. Biederman 4107ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 4116a75ce16SEric W. Biederman { 4126a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 4136a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 414ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 4156a75ce16SEric W. Biederman 4166a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 4176a75ce16SEric W. Biederman unuse_table(head); 418ac13ac6fSEric W. Biederman 419ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4206a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 421ac13ac6fSEric W. Biederman head = NULL; 422ac13ac6fSEric W. Biederman if (ctl_node) { 423ac13ac6fSEric W. Biederman head = ctl_node->header; 424ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4256a75ce16SEric W. Biederman } 4266a75ce16SEric W. Biederman *phead = head; 4276a75ce16SEric W. Biederman *pentry = entry; 4281f87f0b5SEric W. Biederman } 4291f87f0b5SEric W. Biederman 4301f87f0b5SEric W. Biederman /* 4311f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4321f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4331f87f0b5SEric W. Biederman */ 4341f87f0b5SEric W. Biederman 4351f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4361f87f0b5SEric W. Biederman { 437091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4381f87f0b5SEric W. Biederman mode >>= 6; 439091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4401f87f0b5SEric W. Biederman mode >>= 3; 4411f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4421f87f0b5SEric W. Biederman return 0; 4431f87f0b5SEric W. Biederman return -EACCES; 4441f87f0b5SEric W. Biederman } 4451f87f0b5SEric W. Biederman 44673f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4471f87f0b5SEric W. Biederman { 44873f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4491f87f0b5SEric W. Biederman int mode; 4501f87f0b5SEric W. Biederman 4511f87f0b5SEric W. Biederman if (root->permissions) 45273f7ef43SEric W. Biederman mode = root->permissions(head, table); 4531f87f0b5SEric W. Biederman else 4541f87f0b5SEric W. Biederman mode = table->mode; 4551f87f0b5SEric W. Biederman 4561f87f0b5SEric W. Biederman return test_perm(mode, op); 4571f87f0b5SEric W. Biederman } 4581f87f0b5SEric W. Biederman 4599043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4609043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 46177b14db5SEric W. Biederman { 462e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 46377b14db5SEric W. Biederman struct inode *inode; 4649043476fSAl Viro struct proc_inode *ei; 46577b14db5SEric W. Biederman 4669043476fSAl Viro inode = new_inode(sb); 46777b14db5SEric W. Biederman if (!inode) 468ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 46977b14db5SEric W. Biederman 47085fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 47185fe4025SChristoph Hellwig 47277b14db5SEric W. Biederman ei = PROC_I(inode); 4739043476fSAl Viro 474d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 475ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 476ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 477ace0c791SEric W. Biederman iput(inode); 478ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 479ace0c791SEric W. Biederman } 480ace0c791SEric W. Biederman ei->sysctl = head; 481ace0c791SEric W. Biederman ei->sysctl_entry = table; 4822fd1d2c4SEric W. Biederman hlist_add_head_rcu(&ei->sysctl_inodes, &head->inodes); 483d6cffbbeSKonstantin Khlebnikov head->count++; 484d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 485d6cffbbeSKonstantin Khlebnikov 486078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4879043476fSAl Viro inode->i_mode = table->mode; 4887ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4899043476fSAl Viro inode->i_mode |= S_IFREG; 49077b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 49177b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4929043476fSAl Viro } else { 4939043476fSAl Viro inode->i_mode |= S_IFDIR; 4949043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4959043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 496f9bd6733SEric W. Biederman if (is_empty_dir(head)) 497f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4989043476fSAl Viro } 499e79c6a4fSDmitry Torokhov 500e79c6a4fSDmitry Torokhov if (root->set_ownership) 501e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 502e79c6a4fSDmitry Torokhov 50377b14db5SEric W. Biederman return inode; 50477b14db5SEric W. Biederman } 50577b14db5SEric W. Biederman 506d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 507d6cffbbeSKonstantin Khlebnikov { 508d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 5092fd1d2c4SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sysctl_inodes); 510d6cffbbeSKonstantin Khlebnikov if (!--head->count) 511d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 512d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 513d6cffbbeSKonstantin Khlebnikov } 514d6cffbbeSKonstantin Khlebnikov 51581324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 51677b14db5SEric W. Biederman { 5173cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5183cc3e046SEric W. Biederman if (!head) 5190e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5203cc3e046SEric W. Biederman return sysctl_head_grab(head); 52177b14db5SEric W. Biederman } 52277b14db5SEric W. Biederman 52377b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 52400cd8dd3SAl Viro unsigned int flags) 52577b14db5SEric W. Biederman { 5269043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5279043476fSAl Viro struct ctl_table_header *h = NULL; 528dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5299043476fSAl Viro struct ctl_table *p; 53077b14db5SEric W. Biederman struct inode *inode; 5319043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5327ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5330e47c99dSEric W. Biederman int ret; 53477b14db5SEric W. Biederman 5359043476fSAl Viro if (IS_ERR(head)) 5369043476fSAl Viro return ERR_CAST(head); 5379043476fSAl Viro 5387ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5399043476fSAl Viro 5407ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5419043476fSAl Viro if (!p) 54277b14db5SEric W. Biederman goto out; 54377b14db5SEric W. Biederman 5444e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 54513bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5460e47c99dSEric W. Biederman err = ERR_PTR(ret); 5470e47c99dSEric W. Biederman if (ret) 5480e47c99dSEric W. Biederman goto out; 5494e757320SEric W. Biederman } 5500e47c99dSEric W. Biederman 5519043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 552ea5751ccSIvan Delalande if (IS_ERR(inode)) { 553ea5751ccSIvan Delalande err = ERR_CAST(inode); 55477b14db5SEric W. Biederman goto out; 555ea5751ccSIvan Delalande } 55677b14db5SEric W. Biederman 557fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 558888e2b03SAl Viro err = d_splice_alias(inode, dentry); 55977b14db5SEric W. Biederman 56077b14db5SEric W. Biederman out: 5616bf61045SFrancesco Ruggeri if (h) 5626bf61045SFrancesco Ruggeri sysctl_head_finish(h); 56377b14db5SEric W. Biederman sysctl_head_finish(head); 56477b14db5SEric W. Biederman return err; 56577b14db5SEric W. Biederman } 56677b14db5SEric W. Biederman 5677708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 5687708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 56977b14db5SEric W. Biederman { 570496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5719043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5729043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5732a2da53bSDavid Howells ssize_t error; 5742a2da53bSDavid Howells size_t res; 57577b14db5SEric W. Biederman 5769043476fSAl Viro if (IS_ERR(head)) 5779043476fSAl Viro return PTR_ERR(head); 57877b14db5SEric W. Biederman 57977b14db5SEric W. Biederman /* 58077b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 58177b14db5SEric W. Biederman * and won't be until we finish. 58277b14db5SEric W. Biederman */ 58377b14db5SEric W. Biederman error = -EPERM; 58473f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 58577b14db5SEric W. Biederman goto out; 58677b14db5SEric W. Biederman 5879043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5889043476fSAl Viro error = -EINVAL; 5899043476fSAl Viro if (!table->proc_handler) 5909043476fSAl Viro goto out; 5919043476fSAl Viro 5927b146cebSAndrey Ignatov error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write); 5937b146cebSAndrey Ignatov if (error) 5947b146cebSAndrey Ignatov goto out; 5957b146cebSAndrey Ignatov 59677b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 59777b14db5SEric W. Biederman res = count; 5988d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 59977b14db5SEric W. Biederman if (!error) 60077b14db5SEric W. Biederman error = res; 60177b14db5SEric W. Biederman out: 60277b14db5SEric W. Biederman sysctl_head_finish(head); 60377b14db5SEric W. Biederman 60477b14db5SEric W. Biederman return error; 60577b14db5SEric W. Biederman } 60677b14db5SEric W. Biederman 6077708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 6087708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 6097708bfb1SPavel Emelyanov { 6107708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 6117708bfb1SPavel Emelyanov } 6127708bfb1SPavel Emelyanov 61377b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 61477b14db5SEric W. Biederman size_t count, loff_t *ppos) 61577b14db5SEric W. Biederman { 6167708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 61777b14db5SEric W. Biederman } 61877b14db5SEric W. Biederman 619f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 620f1ecf068SLucas De Marchi { 6214e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 622f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 623f1ecf068SLucas De Marchi 6244e474a00SLucas De Marchi /* sysctl was unregistered */ 6254e474a00SLucas De Marchi if (IS_ERR(head)) 6264e474a00SLucas De Marchi return PTR_ERR(head); 6274e474a00SLucas De Marchi 628f1ecf068SLucas De Marchi if (table->poll) 629f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 630f1ecf068SLucas De Marchi 6314e474a00SLucas De Marchi sysctl_head_finish(head); 6324e474a00SLucas De Marchi 633f1ecf068SLucas De Marchi return 0; 634f1ecf068SLucas De Marchi } 635f1ecf068SLucas De Marchi 636076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 637f1ecf068SLucas De Marchi { 638496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6394e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 640f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 641076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6424e474a00SLucas De Marchi unsigned long event; 6434e474a00SLucas De Marchi 6444e474a00SLucas De Marchi /* sysctl was unregistered */ 6454e474a00SLucas De Marchi if (IS_ERR(head)) 646a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 647f1ecf068SLucas De Marchi 648f1ecf068SLucas De Marchi if (!table->proc_handler) 649f1ecf068SLucas De Marchi goto out; 650f1ecf068SLucas De Marchi 651f1ecf068SLucas De Marchi if (!table->poll) 652f1ecf068SLucas De Marchi goto out; 653f1ecf068SLucas De Marchi 6544e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 655f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 656f1ecf068SLucas De Marchi 657f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 658f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 659a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 660f1ecf068SLucas De Marchi } 661f1ecf068SLucas De Marchi 662f1ecf068SLucas De Marchi out: 6634e474a00SLucas De Marchi sysctl_head_finish(head); 6644e474a00SLucas De Marchi 665f1ecf068SLucas De Marchi return ret; 666f1ecf068SLucas De Marchi } 66777b14db5SEric W. Biederman 668f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 669f0c3b509SAl Viro struct dir_context *ctx, 6709043476fSAl Viro struct ctl_table_header *head, 6719043476fSAl Viro struct ctl_table *table) 67277b14db5SEric W. Biederman { 673f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 67477b14db5SEric W. Biederman struct inode *inode; 67577b14db5SEric W. Biederman struct qstr qname; 67677b14db5SEric W. Biederman ino_t ino = 0; 67777b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 67877b14db5SEric W. Biederman 67977b14db5SEric W. Biederman qname.name = table->procname; 68077b14db5SEric W. Biederman qname.len = strlen(table->procname); 6818387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 68277b14db5SEric W. Biederman 68377b14db5SEric W. Biederman child = d_lookup(dir, &qname); 68477b14db5SEric W. Biederman if (!child) { 68576aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 68676aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 68776aab3abSAl Viro if (IS_ERR(child)) 68876aab3abSAl Viro return false; 68976aab3abSAl Viro if (d_in_lookup(child)) { 690888e2b03SAl Viro struct dentry *res; 6919043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 692ea5751ccSIvan Delalande if (IS_ERR(inode)) { 69376aab3abSAl Viro d_lookup_done(child); 6949043476fSAl Viro dput(child); 695f0c3b509SAl Viro return false; 69676aab3abSAl Viro } 697fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 698888e2b03SAl Viro res = d_splice_alias(inode, child); 699888e2b03SAl Viro d_lookup_done(child); 700888e2b03SAl Viro if (unlikely(res)) { 701888e2b03SAl Viro if (IS_ERR(res)) { 702888e2b03SAl Viro dput(child); 703888e2b03SAl Viro return false; 704888e2b03SAl Viro } 705888e2b03SAl Viro dput(child); 706888e2b03SAl Viro child = res; 707888e2b03SAl Viro } 70877b14db5SEric W. Biederman } 70977b14db5SEric W. Biederman } 7102b0143b5SDavid Howells inode = d_inode(child); 71177b14db5SEric W. Biederman ino = inode->i_ino; 71277b14db5SEric W. Biederman type = inode->i_mode >> 12; 71377b14db5SEric W. Biederman dput(child); 714f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7159043476fSAl Viro } 7169043476fSAl Viro 717f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 718f0c3b509SAl Viro struct dir_context *ctx, 7190e47c99dSEric W. Biederman struct ctl_table_header *head, 7200e47c99dSEric W. Biederman struct ctl_table *table) 7210e47c99dSEric W. Biederman { 722f0c3b509SAl Viro bool ret = true; 723a0b0d1c3SDanilo Krummrich 7240e47c99dSEric W. Biederman head = sysctl_head_grab(head); 725a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 726a0b0d1c3SDanilo Krummrich return false; 7270e47c99dSEric W. Biederman 7280e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 729835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7300e47c99dSEric W. Biederman goto out; 7310e47c99dSEric W. Biederman 732f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7330e47c99dSEric W. Biederman out: 7340e47c99dSEric W. Biederman sysctl_head_finish(head); 7350e47c99dSEric W. Biederman return ret; 7360e47c99dSEric W. Biederman } 7370e47c99dSEric W. Biederman 738e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7399043476fSAl Viro unsigned long *pos, struct file *file, 740f0c3b509SAl Viro struct dir_context *ctx) 7419043476fSAl Viro { 742f0c3b509SAl Viro bool res; 7439043476fSAl Viro 744f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 745f0c3b509SAl Viro return true; 7469043476fSAl Viro 7470e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 748f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7490e47c99dSEric W. Biederman else 750f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7519043476fSAl Viro 752f0c3b509SAl Viro if (res) 753f0c3b509SAl Viro ctx->pos = *pos; 7546a75ce16SEric W. Biederman 7556a75ce16SEric W. Biederman return res; 75677b14db5SEric W. Biederman } 75777b14db5SEric W. Biederman 758f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 75977b14db5SEric W. Biederman { 760f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7619043476fSAl Viro struct ctl_table_header *h = NULL; 7626a75ce16SEric W. Biederman struct ctl_table *entry; 7637ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 76477b14db5SEric W. Biederman unsigned long pos; 76577b14db5SEric W. Biederman 7669043476fSAl Viro if (IS_ERR(head)) 7679043476fSAl Viro return PTR_ERR(head); 7689043476fSAl Viro 7697ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 77077b14db5SEric W. Biederman 771f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 77293362fa4SZhou Chengming goto out; 773f0c3b509SAl Viro 77477b14db5SEric W. Biederman pos = 2; 77577b14db5SEric W. Biederman 7767ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 777f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7789043476fSAl Viro sysctl_head_finish(h); 7799043476fSAl Viro break; 78077b14db5SEric W. Biederman } 78177b14db5SEric W. Biederman } 78293362fa4SZhou Chengming out: 78377b14db5SEric W. Biederman sysctl_head_finish(head); 784f0c3b509SAl Viro return 0; 78577b14db5SEric W. Biederman } 78677b14db5SEric W. Biederman 78710556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 78877b14db5SEric W. Biederman { 78977b14db5SEric W. Biederman /* 79077b14db5SEric W. Biederman * sysctl entries that are not writeable, 79177b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 79277b14db5SEric W. Biederman */ 793f696a365SMiklos Szeredi struct ctl_table_header *head; 794f696a365SMiklos Szeredi struct ctl_table *table; 79577b14db5SEric W. Biederman int error; 79677b14db5SEric W. Biederman 797f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 798f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 799f696a365SMiklos Szeredi return -EACCES; 800f696a365SMiklos Szeredi 801f696a365SMiklos Szeredi head = grab_header(inode); 8029043476fSAl Viro if (IS_ERR(head)) 8039043476fSAl Viro return PTR_ERR(head); 80477b14db5SEric W. Biederman 805f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8069043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8079043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8089043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 80973f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8109043476fSAl Viro 81177b14db5SEric W. Biederman sysctl_head_finish(head); 81277b14db5SEric W. Biederman return error; 81377b14db5SEric W. Biederman } 81477b14db5SEric W. Biederman 81577b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 81677b14db5SEric W. Biederman { 8172b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 81877b14db5SEric W. Biederman int error; 81977b14db5SEric W. Biederman 82077b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 82177b14db5SEric W. Biederman return -EPERM; 82277b14db5SEric W. Biederman 82331051c85SJan Kara error = setattr_prepare(dentry, attr); 8241025774cSChristoph Hellwig if (error) 82577b14db5SEric W. Biederman return error; 8261025774cSChristoph Hellwig 8271025774cSChristoph Hellwig setattr_copy(inode, attr); 8281025774cSChristoph Hellwig mark_inode_dirty(inode); 8291025774cSChristoph Hellwig return 0; 83077b14db5SEric W. Biederman } 83177b14db5SEric W. Biederman 832a528d35eSDavid Howells static int proc_sys_getattr(const struct path *path, struct kstat *stat, 833a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8349043476fSAl Viro { 835a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8369043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8379043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8389043476fSAl Viro 8399043476fSAl Viro if (IS_ERR(head)) 8409043476fSAl Viro return PTR_ERR(head); 8419043476fSAl Viro 8429043476fSAl Viro generic_fillattr(inode, stat); 8439043476fSAl Viro if (table) 8449043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8459043476fSAl Viro 8469043476fSAl Viro sysctl_head_finish(head); 8479043476fSAl Viro return 0; 8489043476fSAl Viro } 8499043476fSAl Viro 85077b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 851f1ecf068SLucas De Marchi .open = proc_sys_open, 852f1ecf068SLucas De Marchi .poll = proc_sys_poll, 85377b14db5SEric W. Biederman .read = proc_sys_read, 85477b14db5SEric W. Biederman .write = proc_sys_write, 8556038f373SArnd Bergmann .llseek = default_llseek, 8569043476fSAl Viro }; 8579043476fSAl Viro 8589043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 859887df078SPavel Emelyanov .read = generic_read_dir, 860f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8613222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 86277b14db5SEric W. Biederman }; 86377b14db5SEric W. Biederman 86403a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8659043476fSAl Viro .permission = proc_sys_permission, 8669043476fSAl Viro .setattr = proc_sys_setattr, 8679043476fSAl Viro .getattr = proc_sys_getattr, 8689043476fSAl Viro }; 8699043476fSAl Viro 8709043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 87177b14db5SEric W. Biederman .lookup = proc_sys_lookup, 87277b14db5SEric W. Biederman .permission = proc_sys_permission, 87377b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8749043476fSAl Viro .getattr = proc_sys_getattr, 87577b14db5SEric W. Biederman }; 87677b14db5SEric W. Biederman 8770b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 87877b14db5SEric W. Biederman { 8790b728e19SAl Viro if (flags & LOOKUP_RCU) 88034286d66SNick Piggin return -ECHILD; 8812b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8829043476fSAl Viro } 8839043476fSAl Viro 884fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8859043476fSAl Viro { 8862b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 8879043476fSAl Viro } 8889043476fSAl Viro 8891f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8901f87f0b5SEric W. Biederman { 8911f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8921f87f0b5SEric W. Biederman int res; 8931f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8941f87f0b5SEric W. Biederman if (p->unregistering) 8951f87f0b5SEric W. Biederman res = 0; 8961f87f0b5SEric W. Biederman else if (!set->is_seen) 8971f87f0b5SEric W. Biederman res = 1; 8981f87f0b5SEric W. Biederman else 8991f87f0b5SEric W. Biederman res = set->is_seen(set); 9001f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 9011f87f0b5SEric W. Biederman return res; 9021f87f0b5SEric W. Biederman } 9031f87f0b5SEric W. Biederman 9046fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 905621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 9069043476fSAl Viro { 907dfef6dcdSAl Viro struct ctl_table_header *head; 908da53be12SLinus Torvalds struct inode *inode; 909da53be12SLinus Torvalds 91031e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 91131e6b01fSNick Piggin * that inode here can be NULL */ 912dfef6dcdSAl Viro /* AV: can it, indeed? */ 9132b0143b5SDavid Howells inode = d_inode_rcu(dentry); 91431e6b01fSNick Piggin if (!inode) 915dfef6dcdSAl Viro return 1; 916621e155aSNick Piggin if (name->len != len) 9179043476fSAl Viro return 1; 918621e155aSNick Piggin if (memcmp(name->name, str, len)) 9199043476fSAl Viro return 1; 920dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 921dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 92277b14db5SEric W. Biederman } 92377b14db5SEric W. Biederman 924d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 92577b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9269043476fSAl Viro .d_delete = proc_sys_delete, 9279043476fSAl Viro .d_compare = proc_sys_compare, 92877b14db5SEric W. Biederman }; 92977b14db5SEric W. Biederman 9300e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9317ec66d06SEric W. Biederman const char *name, int namelen) 9321f87f0b5SEric W. Biederman { 9337ec66d06SEric W. Biederman struct ctl_table_header *head; 9347ec66d06SEric W. Biederman struct ctl_table *entry; 9351f87f0b5SEric W. Biederman 9360e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9377ec66d06SEric W. Biederman if (!entry) 9387ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 93951f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9407ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 94151f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9421f87f0b5SEric W. Biederman } 9431f87f0b5SEric W. Biederman 9447ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9457ec66d06SEric W. Biederman const char *name, int namelen) 9461f87f0b5SEric W. Biederman { 9477ec66d06SEric W. Biederman struct ctl_table *table; 9487ec66d06SEric W. Biederman struct ctl_dir *new; 949ac13ac6fSEric W. Biederman struct ctl_node *node; 9507ec66d06SEric W. Biederman char *new_name; 9511f87f0b5SEric W. Biederman 952ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 953ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 954ac13ac6fSEric W. Biederman GFP_KERNEL); 9557ec66d06SEric W. Biederman if (!new) 9567ec66d06SEric W. Biederman return NULL; 9577ec66d06SEric W. Biederman 958ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 959ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9607ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9617ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9627ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9637ec66d06SEric W. Biederman table[0].procname = new_name; 9647ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 965ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9667ec66d06SEric W. Biederman 9677ec66d06SEric W. Biederman return new; 9681f87f0b5SEric W. Biederman } 9691f87f0b5SEric W. Biederman 97060f126d9SEric W. Biederman /** 97160f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 97260f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 97360f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 97460f126d9SEric W. Biederman * @namelen: The length of name 97560f126d9SEric W. Biederman * 97660f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 97760f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 97860f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 97960f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 98060f126d9SEric W. Biederman * simply dropped. 98160f126d9SEric W. Biederman */ 9820e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9830e47c99dSEric W. Biederman const char *name, int namelen) 9847ec66d06SEric W. Biederman { 9850e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9867ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9870eb97f38SEric W. Biederman int err; 9887ec66d06SEric W. Biederman 9897ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9900e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9917ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9927ec66d06SEric W. Biederman goto found; 9937ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9947ec66d06SEric W. Biederman goto failed; 9957ec66d06SEric W. Biederman 9967ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9977ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 9987ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9997ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 10007ec66d06SEric W. Biederman if (!new) 10017ec66d06SEric W. Biederman goto failed; 10027ec66d06SEric W. Biederman 100360f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 10040e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10057ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10067ec66d06SEric W. Biederman goto found; 10077ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10087ec66d06SEric W. Biederman goto failed; 10097ec66d06SEric W. Biederman 101060f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 10110eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 10120eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10130eb97f38SEric W. Biederman if (err) 10140e47c99dSEric W. Biederman goto failed; 10157ec66d06SEric W. Biederman subdir = new; 10167ec66d06SEric W. Biederman found: 10177ec66d06SEric W. Biederman subdir->header.nreg++; 10187ec66d06SEric W. Biederman failed: 1019a1c83681SViresh Kumar if (IS_ERR(subdir)) { 102087ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10216980128fSEric W. Biederman sysctl_print_dir(dir); 102287ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 10237ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 10241f87f0b5SEric W. Biederman } 10257ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10267ec66d06SEric W. Biederman if (new) 10277ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10287ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10297ec66d06SEric W. Biederman return subdir; 10301f87f0b5SEric W. Biederman } 10311f87f0b5SEric W. Biederman 10320e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10330e47c99dSEric W. Biederman { 10340e47c99dSEric W. Biederman struct ctl_dir *parent; 10350e47c99dSEric W. Biederman const char *procname; 10360e47c99dSEric W. Biederman if (!dir->header.parent) 10370e47c99dSEric W. Biederman return &set->dir; 10380e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10390e47c99dSEric W. Biederman if (IS_ERR(parent)) 10400e47c99dSEric W. Biederman return parent; 10410e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10420e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10430e47c99dSEric W. Biederman } 10440e47c99dSEric W. Biederman 10450e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 104613bcc6a2SEric W. Biederman struct ctl_table **pentry) 10470e47c99dSEric W. Biederman { 10480e47c99dSEric W. Biederman struct ctl_table_header *head; 10490e47c99dSEric W. Biederman struct ctl_table_root *root; 10500e47c99dSEric W. Biederman struct ctl_table_set *set; 10510e47c99dSEric W. Biederman struct ctl_table *entry; 10520e47c99dSEric W. Biederman struct ctl_dir *dir; 10530e47c99dSEric W. Biederman int ret; 10540e47c99dSEric W. Biederman 10550e47c99dSEric W. Biederman ret = 0; 10560e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10570e47c99dSEric W. Biederman root = (*pentry)->data; 105813bcc6a2SEric W. Biederman set = lookup_header_set(root); 10590e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10600e47c99dSEric W. Biederman if (IS_ERR(dir)) 10610e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10620e47c99dSEric W. Biederman else { 10630e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10640e47c99dSEric W. Biederman head = NULL; 10650e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10660e47c99dSEric W. Biederman ret = -ENOENT; 10670e47c99dSEric W. Biederman if (entry && use_table(head)) { 10680e47c99dSEric W. Biederman unuse_table(*phead); 10690e47c99dSEric W. Biederman *phead = head; 10700e47c99dSEric W. Biederman *pentry = entry; 10710e47c99dSEric W. Biederman ret = 0; 10720e47c99dSEric W. Biederman } 10730e47c99dSEric W. Biederman } 10740e47c99dSEric W. Biederman 10750e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10760e47c99dSEric W. Biederman return ret; 10770e47c99dSEric W. Biederman } 10780e47c99dSEric W. Biederman 10797c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10807c60c48fSEric W. Biederman { 10817c60c48fSEric W. Biederman struct va_format vaf; 10827c60c48fSEric W. Biederman va_list args; 10837c60c48fSEric W. Biederman 10847c60c48fSEric W. Biederman va_start(args, fmt); 10857c60c48fSEric W. Biederman vaf.fmt = fmt; 10867c60c48fSEric W. Biederman vaf.va = &args; 10877c60c48fSEric W. Biederman 108887ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10897c60c48fSEric W. Biederman path, table->procname, &vaf); 10907c60c48fSEric W. Biederman 10917c60c48fSEric W. Biederman va_end(args); 10927c60c48fSEric W. Biederman return -EINVAL; 10937c60c48fSEric W. Biederman } 10947c60c48fSEric W. Biederman 10954f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 10964f2fec00SLuis R. Rodriguez { 10974f2fec00SLuis R. Rodriguez int err = 0; 10984f2fec00SLuis R. Rodriguez 109961d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 110061d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11014f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 110264a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11034f2fec00SLuis R. Rodriguez } 11044f2fec00SLuis R. Rodriguez 11054f2fec00SLuis R. Rodriguez return err; 11064f2fec00SLuis R. Rodriguez } 11074f2fec00SLuis R. Rodriguez 11087c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 11097c60c48fSEric W. Biederman { 11107c60c48fSEric W. Biederman int err = 0; 11117c60c48fSEric W. Biederman for (; table->procname; table++) { 11127c60c48fSEric W. Biederman if (table->child) 111389c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "Not a file"); 11147c60c48fSEric W. Biederman 11151f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 11161f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 11171680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 111861d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax) || 11191f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 11201f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 11211f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 11221f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 11231f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 11241f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 11251f87f0b5SEric W. Biederman if (!table->data) 112689c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No data"); 11271f87f0b5SEric W. Biederman if (!table->maxlen) 112889c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No maxlen"); 11294f2fec00SLuis R. Rodriguez else 11304f2fec00SLuis R. Rodriguez err |= sysctl_check_table_array(path, table); 11311f87f0b5SEric W. Biederman } 11321f87f0b5SEric W. Biederman if (!table->proc_handler) 113389c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No proc_handler"); 11347c60c48fSEric W. Biederman 11357c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 113689c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "bogus .mode 0%o", 11377c60c48fSEric W. Biederman table->mode); 11381f87f0b5SEric W. Biederman } 11397c60c48fSEric W. Biederman return err; 11401f87f0b5SEric W. Biederman } 11411f87f0b5SEric W. Biederman 11420e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11430e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11440e47c99dSEric W. Biederman { 11450e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11460e47c99dSEric W. Biederman struct ctl_table_header *links; 1147ac13ac6fSEric W. Biederman struct ctl_node *node; 11480e47c99dSEric W. Biederman char *link_name; 11490e47c99dSEric W. Biederman int nr_entries, name_bytes; 11500e47c99dSEric W. Biederman 11510e47c99dSEric W. Biederman name_bytes = 0; 11520e47c99dSEric W. Biederman nr_entries = 0; 11530e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11540e47c99dSEric W. Biederman nr_entries++; 11550e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11560e47c99dSEric W. Biederman } 11570e47c99dSEric W. Biederman 11580e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1159ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11600e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11610e47c99dSEric W. Biederman name_bytes, 11620e47c99dSEric W. Biederman GFP_KERNEL); 11630e47c99dSEric W. Biederman 11640e47c99dSEric W. Biederman if (!links) 11650e47c99dSEric W. Biederman return NULL; 11660e47c99dSEric W. Biederman 1167ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1168ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11690e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11700e47c99dSEric W. Biederman 11710e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11720e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11730e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11740e47c99dSEric W. Biederman link->procname = link_name; 11750e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11760e47c99dSEric W. Biederman link->data = link_root; 11770e47c99dSEric W. Biederman link_name += len; 11780e47c99dSEric W. Biederman } 1179ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11800e47c99dSEric W. Biederman links->nreg = nr_entries; 11810e47c99dSEric W. Biederman 11820e47c99dSEric W. Biederman return links; 11830e47c99dSEric W. Biederman } 11840e47c99dSEric W. Biederman 11850e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11860e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11870e47c99dSEric W. Biederman { 11880e47c99dSEric W. Biederman struct ctl_table_header *head; 11890e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11900e47c99dSEric W. Biederman 11910e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11920e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11930e47c99dSEric W. Biederman const char *procname = entry->procname; 11940e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11950e47c99dSEric W. Biederman if (!link) 11960e47c99dSEric W. Biederman return false; 11970e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 11980e47c99dSEric W. Biederman continue; 11990e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12000e47c99dSEric W. Biederman continue; 12010e47c99dSEric W. Biederman return false; 12020e47c99dSEric W. Biederman } 12030e47c99dSEric W. Biederman 12040e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 12050e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 12060e47c99dSEric W. Biederman const char *procname = entry->procname; 12070e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12080e47c99dSEric W. Biederman head->nreg++; 12090e47c99dSEric W. Biederman } 12100e47c99dSEric W. Biederman return true; 12110e47c99dSEric W. Biederman } 12120e47c99dSEric W. Biederman 12130e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12140e47c99dSEric W. Biederman { 12150e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12160e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 12170e47c99dSEric W. Biederman struct ctl_table_header *links; 12180e47c99dSEric W. Biederman int err; 12190e47c99dSEric W. Biederman 12200e47c99dSEric W. Biederman if (head->set == root_set) 12210e47c99dSEric W. Biederman return 0; 12220e47c99dSEric W. Biederman 12230e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12240e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12250e47c99dSEric W. Biederman return 0; 12260e47c99dSEric W. Biederman 12270e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12280e47c99dSEric W. Biederman return 0; 12290e47c99dSEric W. Biederman 12300e47c99dSEric W. Biederman core_parent->header.nreg++; 12310e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12320e47c99dSEric W. Biederman 12330e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12340e47c99dSEric W. Biederman 12350e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12360e47c99dSEric W. Biederman err = -ENOMEM; 12370e47c99dSEric W. Biederman if (!links) 12380e47c99dSEric W. Biederman goto out; 12390e47c99dSEric W. Biederman 12400e47c99dSEric W. Biederman err = 0; 12410e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12420e47c99dSEric W. Biederman kfree(links); 12430e47c99dSEric W. Biederman goto out; 12440e47c99dSEric W. Biederman } 12450e47c99dSEric W. Biederman 12460e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12470e47c99dSEric W. Biederman if (err) 12480e47c99dSEric W. Biederman kfree(links); 12490e47c99dSEric W. Biederman out: 12500e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12510e47c99dSEric W. Biederman return err; 12520e47c99dSEric W. Biederman } 12530e47c99dSEric W. Biederman 12541f87f0b5SEric W. Biederman /** 1255f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 125660a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12571f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12581f87f0b5SEric W. Biederman * @table: the top-level table structure 12591f87f0b5SEric W. Biederman * 12601f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12611f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12621f87f0b5SEric W. Biederman * 12631f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12641f87f0b5SEric W. Biederman * 12651f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12661f87f0b5SEric W. Biederman * enter a sysctl file 12671f87f0b5SEric W. Biederman * 12681f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12691f87f0b5SEric W. Biederman * 12701f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12711f87f0b5SEric W. Biederman * 1272f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12731f87f0b5SEric W. Biederman * 1274f728019bSEric W. Biederman * child - must be %NULL. 12751f87f0b5SEric W. Biederman * 12761f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12771f87f0b5SEric W. Biederman * 12781f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12791f87f0b5SEric W. Biederman * 12801f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12811f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12821f87f0b5SEric W. Biederman * 1283f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1284f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12851f87f0b5SEric W. Biederman * 12861f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12871f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12881f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12891f87f0b5SEric W. Biederman * 12901f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12911f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12921f87f0b5SEric W. Biederman * 12931f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 12941f87f0b5SEric W. Biederman * to the table header on success. 12951f87f0b5SEric W. Biederman */ 12966e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 129760a47a2eSEric W. Biederman struct ctl_table_set *set, 12986e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 12991f87f0b5SEric W. Biederman { 130060a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13011f87f0b5SEric W. Biederman struct ctl_table_header *header; 13026e9d5164SEric W. Biederman const char *name, *nextname; 13037ec66d06SEric W. Biederman struct ctl_dir *dir; 1304ac13ac6fSEric W. Biederman struct ctl_table *entry; 1305ac13ac6fSEric W. Biederman struct ctl_node *node; 1306ac13ac6fSEric W. Biederman int nr_entries = 0; 13071f87f0b5SEric W. Biederman 1308ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1309ac13ac6fSEric W. Biederman nr_entries++; 1310ac13ac6fSEric W. Biederman 1311ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1312ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 13131f87f0b5SEric W. Biederman if (!header) 13141f87f0b5SEric W. Biederman return NULL; 13151f87f0b5SEric W. Biederman 1316ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1317ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13187c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13197c60c48fSEric W. Biederman goto fail; 13208d6ecfccSEric W. Biederman 13211f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13220e47c99dSEric W. Biederman dir = &set->dir; 132360f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 13247ec66d06SEric W. Biederman dir->header.nreg++; 13257ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13267ec66d06SEric W. Biederman 13277ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 13287ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 13297ec66d06SEric W. Biederman int namelen; 13307ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13317ec66d06SEric W. Biederman if (nextname) { 13327ec66d06SEric W. Biederman namelen = nextname - name; 13337ec66d06SEric W. Biederman nextname++; 13347ec66d06SEric W. Biederman } else { 13357ec66d06SEric W. Biederman namelen = strlen(name); 13367ec66d06SEric W. Biederman } 13377ec66d06SEric W. Biederman if (namelen == 0) 13381f87f0b5SEric W. Biederman continue; 13397ec66d06SEric W. Biederman 13400e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13417ec66d06SEric W. Biederman if (IS_ERR(dir)) 13427ec66d06SEric W. Biederman goto fail; 13431f87f0b5SEric W. Biederman } 13440e47c99dSEric W. Biederman 13457ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13460e47c99dSEric W. Biederman if (insert_header(dir, header)) 13470e47c99dSEric W. Biederman goto fail_put_dir_locked; 13480e47c99dSEric W. Biederman 13497ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13501f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13511f87f0b5SEric W. Biederman 13521f87f0b5SEric W. Biederman return header; 13530e47c99dSEric W. Biederman 13547ec66d06SEric W. Biederman fail_put_dir_locked: 13557ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13567c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13577c60c48fSEric W. Biederman fail: 13587c60c48fSEric W. Biederman kfree(header); 13597c60c48fSEric W. Biederman dump_stack(); 13607c60c48fSEric W. Biederman return NULL; 13611f87f0b5SEric W. Biederman } 13621f87f0b5SEric W. Biederman 1363fea478d4SEric W. Biederman /** 1364fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1365fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1366fea478d4SEric W. Biederman * @table: the table structure 1367fea478d4SEric W. Biederman * 1368fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1369fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1370fea478d4SEric W. Biederman * 1371fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1372fea478d4SEric W. Biederman */ 1373fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1374fea478d4SEric W. Biederman { 1375fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1376fea478d4SEric W. Biederman path, table); 1377fea478d4SEric W. Biederman } 1378fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1379fea478d4SEric W. Biederman 13806e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 13816e9d5164SEric W. Biederman { 13826e9d5164SEric W. Biederman int namelen; 13836e9d5164SEric W. Biederman namelen = strlen(name); 13846e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 13856e9d5164SEric W. Biederman return NULL; 13866e9d5164SEric W. Biederman memcpy(pos, name, namelen); 13876e9d5164SEric W. Biederman pos[namelen] = '/'; 13886e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 13896e9d5164SEric W. Biederman pos += namelen + 1; 13906e9d5164SEric W. Biederman return pos; 13916e9d5164SEric W. Biederman } 13926e9d5164SEric W. Biederman 1393f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1394f728019bSEric W. Biederman { 1395f728019bSEric W. Biederman int has_files = 0; 1396f728019bSEric W. Biederman int nr_subheaders = 0; 1397f728019bSEric W. Biederman struct ctl_table *entry; 1398f728019bSEric W. Biederman 1399f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1400f728019bSEric W. Biederman if (!table || !table->procname) 1401f728019bSEric W. Biederman return 1; 1402f728019bSEric W. Biederman 1403f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1404f728019bSEric W. Biederman if (entry->child) 1405f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1406f728019bSEric W. Biederman else 1407f728019bSEric W. Biederman has_files = 1; 1408f728019bSEric W. Biederman } 1409f728019bSEric W. Biederman return nr_subheaders + has_files; 1410f728019bSEric W. Biederman } 1411f728019bSEric W. Biederman 1412f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 141360a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1414f728019bSEric W. Biederman struct ctl_table *table) 1415f728019bSEric W. Biederman { 1416f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1417f728019bSEric W. Biederman struct ctl_table *entry, *files; 1418f728019bSEric W. Biederman int nr_files = 0; 1419f728019bSEric W. Biederman int nr_dirs = 0; 1420f728019bSEric W. Biederman int err = -ENOMEM; 1421f728019bSEric W. Biederman 1422f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1423f728019bSEric W. Biederman if (entry->child) 1424f728019bSEric W. Biederman nr_dirs++; 1425f728019bSEric W. Biederman else 1426f728019bSEric W. Biederman nr_files++; 1427f728019bSEric W. Biederman } 1428f728019bSEric W. Biederman 1429f728019bSEric W. Biederman files = table; 1430f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1431f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1432f728019bSEric W. Biederman struct ctl_table *new; 14336396bb22SKees Cook files = kcalloc(nr_files + 1, sizeof(struct ctl_table), 1434f728019bSEric W. Biederman GFP_KERNEL); 1435f728019bSEric W. Biederman if (!files) 1436f728019bSEric W. Biederman goto out; 1437f728019bSEric W. Biederman 1438f728019bSEric W. Biederman ctl_table_arg = files; 1439f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1440f728019bSEric W. Biederman if (entry->child) 1441f728019bSEric W. Biederman continue; 1442f728019bSEric W. Biederman *new = *entry; 1443f728019bSEric W. Biederman new++; 1444f728019bSEric W. Biederman } 1445f728019bSEric W. Biederman } 1446f728019bSEric W. Biederman 1447f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1448f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1449f728019bSEric W. Biederman struct ctl_table_header *header; 145060a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1451f728019bSEric W. Biederman if (!header) { 1452f728019bSEric W. Biederman kfree(ctl_table_arg); 1453f728019bSEric W. Biederman goto out; 1454f728019bSEric W. Biederman } 1455f728019bSEric W. Biederman 1456f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1457f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1458f728019bSEric W. Biederman **subheader = header; 1459f728019bSEric W. Biederman (*subheader)++; 1460f728019bSEric W. Biederman } 1461f728019bSEric W. Biederman 1462f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1463f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1464f728019bSEric W. Biederman char *child_pos; 1465f728019bSEric W. Biederman 1466f728019bSEric W. Biederman if (!entry->child) 1467f728019bSEric W. Biederman continue; 1468f728019bSEric W. Biederman 1469f728019bSEric W. Biederman err = -ENAMETOOLONG; 1470f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1471f728019bSEric W. Biederman if (!child_pos) 1472f728019bSEric W. Biederman goto out; 1473f728019bSEric W. Biederman 1474f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 147560a47a2eSEric W. Biederman set, entry->child); 1476f728019bSEric W. Biederman pos[0] = '\0'; 1477f728019bSEric W. Biederman if (err) 1478f728019bSEric W. Biederman goto out; 1479f728019bSEric W. Biederman } 1480f728019bSEric W. Biederman err = 0; 1481f728019bSEric W. Biederman out: 1482f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1483f728019bSEric W. Biederman return err; 1484f728019bSEric W. Biederman } 1485f728019bSEric W. Biederman 14866e9d5164SEric W. Biederman /** 14876e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 148860a47a2eSEric W. Biederman * @set: Sysctl tree to register on 14896e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14906e9d5164SEric W. Biederman * @table: the top-level table structure 14916e9d5164SEric W. Biederman * 14926e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14936e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14946e9d5164SEric W. Biederman * 14956e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 14966e9d5164SEric W. Biederman */ 14976e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 149860a47a2eSEric W. Biederman struct ctl_table_set *set, 14996e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 15006e9d5164SEric W. Biederman { 1501ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1502f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1503f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 15046e9d5164SEric W. Biederman const struct ctl_path *component; 15056e9d5164SEric W. Biederman char *new_path, *pos; 15066e9d5164SEric W. Biederman 15076e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 15086e9d5164SEric W. Biederman if (!new_path) 15096e9d5164SEric W. Biederman return NULL; 15106e9d5164SEric W. Biederman 15116e9d5164SEric W. Biederman pos[0] = '\0'; 15126e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15136e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15146e9d5164SEric W. Biederman if (!pos) 15156e9d5164SEric W. Biederman goto out; 15166e9d5164SEric W. Biederman } 1517ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1518ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1519ec6a5266SEric W. Biederman if (!pos) 1520ec6a5266SEric W. Biederman goto out; 1521ec6a5266SEric W. Biederman table = table->child; 1522ec6a5266SEric W. Biederman } 1523f728019bSEric W. Biederman if (nr_subheaders == 1) { 152460a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1525ec6a5266SEric W. Biederman if (header) 1526ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1527f728019bSEric W. Biederman } else { 1528f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1529f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1530f728019bSEric W. Biederman if (!header) 1531f728019bSEric W. Biederman goto out; 1532f728019bSEric W. Biederman 1533f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1534f728019bSEric W. Biederman subheader = subheaders; 1535f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1536f728019bSEric W. Biederman 1537f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 153860a47a2eSEric W. Biederman set, table)) 1539f728019bSEric W. Biederman goto err_register_leaves; 1540f728019bSEric W. Biederman } 1541f728019bSEric W. Biederman 15426e9d5164SEric W. Biederman out: 15436e9d5164SEric W. Biederman kfree(new_path); 15446e9d5164SEric W. Biederman return header; 1545f728019bSEric W. Biederman 1546f728019bSEric W. Biederman err_register_leaves: 1547f728019bSEric W. Biederman while (subheader > subheaders) { 1548f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1549f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1550f728019bSEric W. Biederman unregister_sysctl_table(subh); 1551f728019bSEric W. Biederman kfree(table); 1552f728019bSEric W. Biederman } 1553f728019bSEric W. Biederman kfree(header); 1554f728019bSEric W. Biederman header = NULL; 1555f728019bSEric W. Biederman goto out; 15566e9d5164SEric W. Biederman } 15576e9d5164SEric W. Biederman 15581f87f0b5SEric W. Biederman /** 15591f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 15601f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15611f87f0b5SEric W. Biederman * @table: the top-level table structure 15621f87f0b5SEric W. Biederman * 15631f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15641f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15651f87f0b5SEric W. Biederman * 15661f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 15671f87f0b5SEric W. Biederman */ 15681f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 15691f87f0b5SEric W. Biederman struct ctl_table *table) 15701f87f0b5SEric W. Biederman { 157160a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 15721f87f0b5SEric W. Biederman path, table); 15731f87f0b5SEric W. Biederman } 15741f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 15751f87f0b5SEric W. Biederman 15761f87f0b5SEric W. Biederman /** 15771f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 15781f87f0b5SEric W. Biederman * @table: the top-level table structure 15791f87f0b5SEric W. Biederman * 15801f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15811f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15821f87f0b5SEric W. Biederman * 15831f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 15841f87f0b5SEric W. Biederman */ 15851f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 15861f87f0b5SEric W. Biederman { 15871f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 15881f87f0b5SEric W. Biederman 15891f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 15901f87f0b5SEric W. Biederman } 15911f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 15921f87f0b5SEric W. Biederman 15930e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 15940e47c99dSEric W. Biederman { 15950e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 15960e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 15970e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 15980e47c99dSEric W. Biederman struct ctl_dir *core_parent; 15990e47c99dSEric W. Biederman struct ctl_table *entry; 16000e47c99dSEric W. Biederman 16010e47c99dSEric W. Biederman if (header->set == root_set) 16020e47c99dSEric W. Biederman return; 16030e47c99dSEric W. Biederman 16040e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 16050e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 16060e47c99dSEric W. Biederman return; 16070e47c99dSEric W. Biederman 16080e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 16090e47c99dSEric W. Biederman struct ctl_table_header *link_head; 16100e47c99dSEric W. Biederman struct ctl_table *link; 16110e47c99dSEric W. Biederman const char *name = entry->procname; 16120e47c99dSEric W. Biederman 16130e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 16140e47c99dSEric W. Biederman if (link && 16150e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 16160e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 16170e47c99dSEric W. Biederman drop_sysctl_table(link_head); 16180e47c99dSEric W. Biederman } 16190e47c99dSEric W. Biederman else { 162087ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 16210e47c99dSEric W. Biederman sysctl_print_dir(parent); 162287ebdc00SAndrew Morton pr_cont("/%s\n", name); 16230e47c99dSEric W. Biederman } 16240e47c99dSEric W. Biederman } 16250e47c99dSEric W. Biederman } 16260e47c99dSEric W. Biederman 1627938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1628938aaa4fSEric W. Biederman { 16297ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 16307ec66d06SEric W. Biederman 1631938aaa4fSEric W. Biederman if (--header->nreg) 1632938aaa4fSEric W. Biederman return; 1633938aaa4fSEric W. Biederman 163423da9588SYueHaibing if (parent) 16350e47c99dSEric W. Biederman put_links(header); 1636938aaa4fSEric W. Biederman start_unregistering(header); 1637938aaa4fSEric W. Biederman if (!--header->count) 1638938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16397ec66d06SEric W. Biederman 16407ec66d06SEric W. Biederman if (parent) 16417ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1642938aaa4fSEric W. Biederman } 1643938aaa4fSEric W. Biederman 16441f87f0b5SEric W. Biederman /** 16451f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16461f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16471f87f0b5SEric W. Biederman * 16481f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16491f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16501f87f0b5SEric W. Biederman */ 16511f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16521f87f0b5SEric W. Biederman { 1653f728019bSEric W. Biederman int nr_subheaders; 16541f87f0b5SEric W. Biederman might_sleep(); 16551f87f0b5SEric W. Biederman 16561f87f0b5SEric W. Biederman if (header == NULL) 16571f87f0b5SEric W. Biederman return; 16581f87f0b5SEric W. Biederman 1659f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1660f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1661f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1662f728019bSEric W. Biederman int i; 1663f728019bSEric W. Biederman 1664f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1665f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1666f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1667f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1668f728019bSEric W. Biederman unregister_sysctl_table(subh); 1669f728019bSEric W. Biederman kfree(table); 1670f728019bSEric W. Biederman } 1671f728019bSEric W. Biederman kfree(header); 1672f728019bSEric W. Biederman return; 1673f728019bSEric W. Biederman } 1674f728019bSEric W. Biederman 16751f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1676938aaa4fSEric W. Biederman drop_sysctl_table(header); 16771f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 16781f87f0b5SEric W. Biederman } 16791f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 16801f87f0b5SEric W. Biederman 16810e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 16829eb47c26SEric W. Biederman struct ctl_table_root *root, 16831f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 16841f87f0b5SEric W. Biederman { 16851347440dSDan Carpenter memset(set, 0, sizeof(*set)); 16860e47c99dSEric W. Biederman set->is_seen = is_seen; 1687ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 16881f87f0b5SEric W. Biederman } 16891f87f0b5SEric W. Biederman 169097324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 169197324cd8SEric W. Biederman { 1692ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 169397324cd8SEric W. Biederman } 16941f87f0b5SEric W. Biederman 16951e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 169677b14db5SEric W. Biederman { 1697e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1698e1675231SAlexey Dobriyan 169977b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 17009043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 17019043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 170277b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1703de4e83bdSEric W. Biederman 1704de4e83bdSEric W. Biederman return sysctl_init(); 170577b14db5SEric W. Biederman } 1706