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> 1677b14db5SEric W. Biederman #include "internal.h" 1777b14db5SEric W. Biederman 18d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1977b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 2003a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 219043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 229043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 2377b14db5SEric W. Biederman 24f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 25f9bd6733SEric W. Biederman 26f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 27f9bd6733SEric W. Biederman { } 28f9bd6733SEric W. Biederman }; 29f9bd6733SEric W. Biederman 30f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 31f9bd6733SEric W. Biederman { 32f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 33f9bd6733SEric W. Biederman } 34f9bd6733SEric W. Biederman 35f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 36f9bd6733SEric W. Biederman { 37f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 38f9bd6733SEric W. Biederman } 39f9bd6733SEric W. Biederman 40f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 41f9bd6733SEric W. Biederman 42f9bd6733SEric W. Biederman { 43f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 44f9bd6733SEric W. Biederman } 45f9bd6733SEric W. Biederman 46f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 47f1ecf068SLucas De Marchi { 48f1ecf068SLucas De Marchi if (!poll) 49f1ecf068SLucas De Marchi return; 50f1ecf068SLucas De Marchi 51f1ecf068SLucas De Marchi atomic_inc(&poll->event); 52f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 53f1ecf068SLucas De Marchi } 54f1ecf068SLucas De Marchi 55a194558eSEric W. Biederman static struct ctl_table root_table[] = { 56a194558eSEric W. Biederman { 57a194558eSEric W. Biederman .procname = "", 587ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 59a194558eSEric W. Biederman }, 60a194558eSEric W. Biederman { } 61a194558eSEric W. Biederman }; 620e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 630e47c99dSEric W. Biederman .default_set.dir.header = { 641f87f0b5SEric W. Biederman {{.count = 1, 65938aaa4fSEric W. Biederman .nreg = 1, 66ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 670e47c99dSEric W. Biederman .ctl_table_arg = root_table, 681f87f0b5SEric W. Biederman .root = &sysctl_table_root, 691f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 707ec66d06SEric W. Biederman }, 711f87f0b5SEric W. Biederman }; 721f87f0b5SEric W. Biederman 731f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 741f87f0b5SEric W. Biederman 757ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 760e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 7713bcc6a2SEric W. Biederman struct ctl_table **pentry); 780e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 790e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 807ec66d06SEric W. Biederman 816980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 826980128fSEric W. Biederman { 836980128fSEric W. Biederman if (dir->header.parent) 846980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 8587ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 866980128fSEric W. Biederman } 876980128fSEric W. Biederman 88076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 89076c3eedSEric W. Biederman { 90076c3eedSEric W. Biederman int minlen; 91076c3eedSEric W. Biederman int cmp; 92076c3eedSEric W. Biederman 93076c3eedSEric W. Biederman minlen = len1; 94076c3eedSEric W. Biederman if (minlen > len2) 95076c3eedSEric W. Biederman minlen = len2; 96076c3eedSEric W. Biederman 97076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 98076c3eedSEric W. Biederman if (cmp == 0) 99076c3eedSEric W. Biederman cmp = len1 - len2; 100076c3eedSEric W. Biederman return cmp; 101076c3eedSEric W. Biederman } 102076c3eedSEric W. Biederman 10360f126d9SEric W. Biederman /* Called under sysctl_lock */ 104076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1050e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 106076c3eedSEric W. Biederman { 107076c3eedSEric W. Biederman struct ctl_table_header *head; 108076c3eedSEric W. Biederman struct ctl_table *entry; 109ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 110076c3eedSEric W. Biederman 111ac13ac6fSEric W. Biederman while (node) 112ac13ac6fSEric W. Biederman { 113ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 114ac13ac6fSEric W. Biederman const char *procname; 115ac13ac6fSEric W. Biederman int cmp; 116ac13ac6fSEric W. Biederman 117ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 118ac13ac6fSEric W. Biederman head = ctl_node->header; 119ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 120ac13ac6fSEric W. Biederman procname = entry->procname; 121ac13ac6fSEric W. Biederman 122ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 123ac13ac6fSEric W. Biederman if (cmp < 0) 124ac13ac6fSEric W. Biederman node = node->rb_left; 125ac13ac6fSEric W. Biederman else if (cmp > 0) 126ac13ac6fSEric W. Biederman node = node->rb_right; 127ac13ac6fSEric W. Biederman else { 128076c3eedSEric W. Biederman *phead = head; 129076c3eedSEric W. Biederman return entry; 130076c3eedSEric W. Biederman } 131076c3eedSEric W. Biederman } 132076c3eedSEric W. Biederman return NULL; 133076c3eedSEric W. Biederman } 134076c3eedSEric W. Biederman 135ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 136ac13ac6fSEric W. Biederman { 137ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 138ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 139ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 140ac13ac6fSEric W. Biederman const char *name = entry->procname; 141ac13ac6fSEric W. Biederman int namelen = strlen(name); 142ac13ac6fSEric W. Biederman 143ac13ac6fSEric W. Biederman while (*p) { 144ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 145ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 146ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 147ac13ac6fSEric W. Biederman const char *parent_name; 148ac13ac6fSEric W. Biederman int cmp; 149ac13ac6fSEric W. Biederman 150ac13ac6fSEric W. Biederman parent = *p; 151ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 152ac13ac6fSEric W. Biederman parent_head = parent_node->header; 153ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 154ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 155ac13ac6fSEric W. Biederman 156ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 157ac13ac6fSEric W. Biederman if (cmp < 0) 158ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 159ac13ac6fSEric W. Biederman else if (cmp > 0) 160ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 161ac13ac6fSEric W. Biederman else { 16287ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 163ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 16487ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 165ac13ac6fSEric W. Biederman return -EEXIST; 166ac13ac6fSEric W. Biederman } 167ac13ac6fSEric W. Biederman } 168ac13ac6fSEric W. Biederman 169ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 170ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 171ac13ac6fSEric W. Biederman return 0; 172ac13ac6fSEric W. Biederman } 173ac13ac6fSEric W. Biederman 174ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 175ac13ac6fSEric W. Biederman { 176ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 177ac13ac6fSEric W. Biederman 178ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 179ac13ac6fSEric W. Biederman } 180ac13ac6fSEric W. Biederman 181e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 182e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 183ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 184e0d04529SEric W. Biederman { 1857ec66d06SEric W. Biederman head->ctl_table = table; 186e0d04529SEric W. Biederman head->ctl_table_arg = table; 187e0d04529SEric W. Biederman head->used = 0; 188e0d04529SEric W. Biederman head->count = 1; 189e0d04529SEric W. Biederman head->nreg = 1; 190e0d04529SEric W. Biederman head->unregistering = NULL; 191e0d04529SEric W. Biederman head->root = root; 192e0d04529SEric W. Biederman head->set = set; 193e0d04529SEric W. Biederman head->parent = NULL; 194ac13ac6fSEric W. Biederman head->node = node; 1952fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 196ac13ac6fSEric W. Biederman if (node) { 197ac13ac6fSEric W. Biederman struct ctl_table *entry; 1984c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 199ac13ac6fSEric W. Biederman node->header = head; 200ac13ac6fSEric W. Biederman } 201ac13ac6fSEric W. Biederman } 202e0d04529SEric W. Biederman 2038425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2048425d6aaSEric W. Biederman { 205ac13ac6fSEric W. Biederman struct ctl_table *entry; 206ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 207ac13ac6fSEric W. Biederman erase_entry(head, entry); 2088425d6aaSEric W. Biederman } 2098425d6aaSEric W. Biederman 2100e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2118425d6aaSEric W. Biederman { 212ac13ac6fSEric W. Biederman struct ctl_table *entry; 2130e47c99dSEric W. Biederman int err; 2140e47c99dSEric W. Biederman 215f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 216f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 217f9bd6733SEric W. Biederman return -EROFS; 218f9bd6733SEric W. Biederman 219f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 220f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 221f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 222f9bd6733SEric W. Biederman return -EINVAL; 223f9bd6733SEric W. Biederman set_empty_dir(dir); 224f9bd6733SEric W. Biederman } 225f9bd6733SEric W. Biederman 2260e47c99dSEric W. Biederman dir->header.nreg++; 2277ec66d06SEric W. Biederman header->parent = dir; 2280e47c99dSEric W. Biederman err = insert_links(header); 2290e47c99dSEric W. Biederman if (err) 2300e47c99dSEric W. Biederman goto fail_links; 231ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 232ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 233ac13ac6fSEric W. Biederman if (err) 234ac13ac6fSEric W. Biederman goto fail; 235ac13ac6fSEric W. Biederman } 2360e47c99dSEric W. Biederman return 0; 237ac13ac6fSEric W. Biederman fail: 238ac13ac6fSEric W. Biederman erase_header(header); 239ac13ac6fSEric W. Biederman put_links(header); 2400e47c99dSEric W. Biederman fail_links: 241f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 242f9bd6733SEric W. Biederman clear_empty_dir(dir); 2430e47c99dSEric W. Biederman header->parent = NULL; 2440e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2450e47c99dSEric W. Biederman return err; 2468425d6aaSEric W. Biederman } 2478425d6aaSEric W. Biederman 2481f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2491f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2501f87f0b5SEric W. Biederman { 2511f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2521f87f0b5SEric W. Biederman return 0; 2531f87f0b5SEric W. Biederman p->used++; 2541f87f0b5SEric W. Biederman return 1; 2551f87f0b5SEric W. Biederman } 2561f87f0b5SEric W. Biederman 2571f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2581f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2591f87f0b5SEric W. Biederman { 2601f87f0b5SEric W. Biederman if (!--p->used) 2611f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2621f87f0b5SEric W. Biederman complete(p->unregistering); 2631f87f0b5SEric W. Biederman } 2641f87f0b5SEric W. Biederman 265d6cffbbeSKonstantin Khlebnikov static void proc_sys_prune_dcache(struct ctl_table_header *head) 266d6cffbbeSKonstantin Khlebnikov { 2672fd1d2c4SEric W. Biederman struct inode *inode; 268d6cffbbeSKonstantin Khlebnikov struct proc_inode *ei; 2692fd1d2c4SEric W. Biederman struct hlist_node *node; 2702fd1d2c4SEric W. Biederman struct super_block *sb; 271d6cffbbeSKonstantin Khlebnikov 272ace0c791SEric W. Biederman rcu_read_lock(); 2732fd1d2c4SEric W. Biederman for (;;) { 2742fd1d2c4SEric W. Biederman node = hlist_first_rcu(&head->inodes); 2752fd1d2c4SEric W. Biederman if (!node) 2762fd1d2c4SEric W. Biederman break; 2772fd1d2c4SEric W. Biederman ei = hlist_entry(node, struct proc_inode, sysctl_inodes); 2782fd1d2c4SEric W. Biederman spin_lock(&sysctl_lock); 2792fd1d2c4SEric W. Biederman hlist_del_init_rcu(&ei->sysctl_inodes); 2802fd1d2c4SEric W. Biederman spin_unlock(&sysctl_lock); 2812fd1d2c4SEric W. Biederman 2822fd1d2c4SEric W. Biederman inode = &ei->vfs_inode; 2832fd1d2c4SEric W. Biederman sb = inode->i_sb; 2842fd1d2c4SEric W. Biederman if (!atomic_inc_not_zero(&sb->s_active)) 2852fd1d2c4SEric W. Biederman continue; 2862fd1d2c4SEric W. Biederman inode = igrab(inode); 287ace0c791SEric W. Biederman rcu_read_unlock(); 2882fd1d2c4SEric W. Biederman if (unlikely(!inode)) { 2892fd1d2c4SEric W. Biederman deactivate_super(sb); 2902fd1d2c4SEric W. Biederman rcu_read_lock(); 2912fd1d2c4SEric W. Biederman continue; 2922fd1d2c4SEric W. Biederman } 2932fd1d2c4SEric W. Biederman 294d6cffbbeSKonstantin Khlebnikov d_prune_aliases(inode); 2952fd1d2c4SEric W. Biederman iput(inode); 2962fd1d2c4SEric W. Biederman deactivate_super(sb); 2972fd1d2c4SEric W. Biederman 298ace0c791SEric W. Biederman rcu_read_lock(); 299d6cffbbeSKonstantin Khlebnikov } 300ace0c791SEric W. Biederman rcu_read_unlock(); 301d6cffbbeSKonstantin Khlebnikov } 302d6cffbbeSKonstantin Khlebnikov 3031f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 3041f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 3051f87f0b5SEric W. Biederman { 3061f87f0b5SEric W. Biederman /* 3071f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 3081f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 3091f87f0b5SEric W. Biederman */ 3101f87f0b5SEric W. Biederman if (unlikely(p->used)) { 3111f87f0b5SEric W. Biederman struct completion wait; 3121f87f0b5SEric W. Biederman init_completion(&wait); 3131f87f0b5SEric W. Biederman p->unregistering = &wait; 3141f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3151f87f0b5SEric W. Biederman wait_for_completion(&wait); 3161f87f0b5SEric W. Biederman } else { 3171f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3181f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 319ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3201f87f0b5SEric W. Biederman } 3211f87f0b5SEric W. Biederman /* 322d6cffbbeSKonstantin Khlebnikov * Prune dentries for unregistered sysctls: namespaced sysctls 323d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 324d6cffbbeSKonstantin Khlebnikov */ 325d6cffbbeSKonstantin Khlebnikov proc_sys_prune_dcache(p); 326d6cffbbeSKonstantin Khlebnikov /* 3271f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3281f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3291f87f0b5SEric W. Biederman */ 330ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3318425d6aaSEric W. Biederman erase_header(p); 3321f87f0b5SEric W. Biederman } 3331f87f0b5SEric W. Biederman 3341f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3351f87f0b5SEric W. Biederman { 336ab4a1f24SPrasad Joshi BUG_ON(!head); 3371f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3381f87f0b5SEric W. Biederman if (!use_table(head)) 3391f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3401f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3411f87f0b5SEric W. Biederman return head; 3421f87f0b5SEric W. Biederman } 3431f87f0b5SEric W. Biederman 3441f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3451f87f0b5SEric W. Biederman { 3461f87f0b5SEric W. Biederman if (!head) 3471f87f0b5SEric W. Biederman return; 3481f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3491f87f0b5SEric W. Biederman unuse_table(head); 3501f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3511f87f0b5SEric W. Biederman } 3521f87f0b5SEric W. Biederman 3531f87f0b5SEric W. Biederman static struct ctl_table_set * 35413bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3551f87f0b5SEric W. Biederman { 3561f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3571f87f0b5SEric W. Biederman if (root->lookup) 35813bcc6a2SEric W. Biederman set = root->lookup(root); 3591f87f0b5SEric W. Biederman return set; 3601f87f0b5SEric W. Biederman } 3611f87f0b5SEric W. Biederman 362076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3637ec66d06SEric W. Biederman struct ctl_dir *dir, 364076c3eedSEric W. Biederman const char *name, int namelen) 365076c3eedSEric W. Biederman { 366076c3eedSEric W. Biederman struct ctl_table_header *head; 367076c3eedSEric W. Biederman struct ctl_table *entry; 368076c3eedSEric W. Biederman 369076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3700e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 371076c3eedSEric W. Biederman if (entry && use_table(head)) 372076c3eedSEric W. Biederman *phead = head; 373076c3eedSEric W. Biederman else 374076c3eedSEric W. Biederman entry = NULL; 375076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 376076c3eedSEric W. Biederman return entry; 377076c3eedSEric W. Biederman } 378076c3eedSEric W. Biederman 379ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3801f87f0b5SEric W. Biederman { 381ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3821f87f0b5SEric W. Biederman 383ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 384ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 385ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 386ac13ac6fSEric W. Biederman return ctl_node; 3871f87f0b5SEric W. Biederman } 3881f87f0b5SEric W. Biederman return NULL; 3891f87f0b5SEric W. Biederman } 3901f87f0b5SEric W. Biederman 3917ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3926a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3931f87f0b5SEric W. Biederman { 394ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3957ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 396ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3976a75ce16SEric W. Biederman 3986a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 399ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 4006a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 401ac13ac6fSEric W. Biederman if (ctl_node) { 402ac13ac6fSEric W. Biederman head = ctl_node->header; 403ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 404ac13ac6fSEric W. Biederman } 4056a75ce16SEric W. Biederman *phead = head; 4066a75ce16SEric W. Biederman *pentry = entry; 4076a75ce16SEric W. Biederman } 4086a75ce16SEric W. Biederman 4097ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 4106a75ce16SEric W. Biederman { 4116a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 4126a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 413ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 4146a75ce16SEric W. Biederman 4156a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 4166a75ce16SEric W. Biederman unuse_table(head); 417ac13ac6fSEric W. Biederman 418ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4196a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 420ac13ac6fSEric W. Biederman head = NULL; 421ac13ac6fSEric W. Biederman if (ctl_node) { 422ac13ac6fSEric W. Biederman head = ctl_node->header; 423ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4246a75ce16SEric W. Biederman } 4256a75ce16SEric W. Biederman *phead = head; 4266a75ce16SEric W. Biederman *pentry = entry; 4271f87f0b5SEric W. Biederman } 4281f87f0b5SEric W. Biederman 4291f87f0b5SEric W. Biederman /* 4301f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4311f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4321f87f0b5SEric W. Biederman */ 4331f87f0b5SEric W. Biederman 4341f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4351f87f0b5SEric W. Biederman { 436091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4371f87f0b5SEric W. Biederman mode >>= 6; 438091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4391f87f0b5SEric W. Biederman mode >>= 3; 4401f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4411f87f0b5SEric W. Biederman return 0; 4421f87f0b5SEric W. Biederman return -EACCES; 4431f87f0b5SEric W. Biederman } 4441f87f0b5SEric W. Biederman 44573f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4461f87f0b5SEric W. Biederman { 44773f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4481f87f0b5SEric W. Biederman int mode; 4491f87f0b5SEric W. Biederman 4501f87f0b5SEric W. Biederman if (root->permissions) 45173f7ef43SEric W. Biederman mode = root->permissions(head, table); 4521f87f0b5SEric W. Biederman else 4531f87f0b5SEric W. Biederman mode = table->mode; 4541f87f0b5SEric W. Biederman 4551f87f0b5SEric W. Biederman return test_perm(mode, op); 4561f87f0b5SEric W. Biederman } 4571f87f0b5SEric W. Biederman 4589043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4599043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 46077b14db5SEric W. Biederman { 461e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 46277b14db5SEric W. Biederman struct inode *inode; 4639043476fSAl Viro struct proc_inode *ei; 46477b14db5SEric W. Biederman 4659043476fSAl Viro inode = new_inode(sb); 46677b14db5SEric W. Biederman if (!inode) 46777b14db5SEric W. Biederman goto out; 46877b14db5SEric W. Biederman 46985fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 47085fe4025SChristoph Hellwig 47177b14db5SEric W. Biederman ei = PROC_I(inode); 4729043476fSAl Viro 473d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 474ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 475ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 476ace0c791SEric W. Biederman iput(inode); 477ace0c791SEric W. Biederman inode = NULL; 478ace0c791SEric W. Biederman goto out; 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 out: 50477b14db5SEric W. Biederman return inode; 50577b14db5SEric W. Biederman } 50677b14db5SEric W. Biederman 507d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 508d6cffbbeSKonstantin Khlebnikov { 509d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 5102fd1d2c4SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sysctl_inodes); 511d6cffbbeSKonstantin Khlebnikov if (!--head->count) 512d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 513d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 514d6cffbbeSKonstantin Khlebnikov } 515d6cffbbeSKonstantin Khlebnikov 51681324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 51777b14db5SEric W. Biederman { 5183cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5193cc3e046SEric W. Biederman if (!head) 5200e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5213cc3e046SEric W. Biederman return sysctl_head_grab(head); 52277b14db5SEric W. Biederman } 52377b14db5SEric W. Biederman 52477b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 52500cd8dd3SAl Viro unsigned int flags) 52677b14db5SEric W. Biederman { 5279043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5289043476fSAl Viro struct ctl_table_header *h = NULL; 529dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5309043476fSAl Viro struct ctl_table *p; 53177b14db5SEric W. Biederman struct inode *inode; 5329043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5337ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5340e47c99dSEric W. Biederman int ret; 53577b14db5SEric W. Biederman 5369043476fSAl Viro if (IS_ERR(head)) 5379043476fSAl Viro return ERR_CAST(head); 5389043476fSAl Viro 5397ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5409043476fSAl Viro 5417ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5429043476fSAl Viro if (!p) 54377b14db5SEric W. Biederman goto out; 54477b14db5SEric W. Biederman 5454e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 54613bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5470e47c99dSEric W. Biederman err = ERR_PTR(ret); 5480e47c99dSEric W. Biederman if (ret) 5490e47c99dSEric W. Biederman goto out; 5504e757320SEric W. Biederman } 5510e47c99dSEric W. Biederman 55277b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 5539043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 55477b14db5SEric W. Biederman if (!inode) 55577b14db5SEric W. Biederman goto out; 55677b14db5SEric W. Biederman 55777b14db5SEric W. Biederman err = NULL; 558fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 55977b14db5SEric W. Biederman d_add(dentry, inode); 56077b14db5SEric W. Biederman 56177b14db5SEric W. Biederman out: 5626bf61045SFrancesco Ruggeri if (h) 5636bf61045SFrancesco Ruggeri sysctl_head_finish(h); 56477b14db5SEric W. Biederman sysctl_head_finish(head); 56577b14db5SEric W. Biederman return err; 56677b14db5SEric W. Biederman } 56777b14db5SEric W. Biederman 5687708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 5697708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 57077b14db5SEric W. Biederman { 571496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5729043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5739043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5742a2da53bSDavid Howells ssize_t error; 5752a2da53bSDavid Howells size_t res; 57677b14db5SEric W. Biederman 5779043476fSAl Viro if (IS_ERR(head)) 5789043476fSAl Viro return PTR_ERR(head); 57977b14db5SEric W. Biederman 58077b14db5SEric W. Biederman /* 58177b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 58277b14db5SEric W. Biederman * and won't be until we finish. 58377b14db5SEric W. Biederman */ 58477b14db5SEric W. Biederman error = -EPERM; 58573f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 58677b14db5SEric W. Biederman goto out; 58777b14db5SEric W. Biederman 5889043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5899043476fSAl Viro error = -EINVAL; 5909043476fSAl Viro if (!table->proc_handler) 5919043476fSAl Viro goto out; 5929043476fSAl Viro 59377b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 59477b14db5SEric W. Biederman res = count; 5958d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 59677b14db5SEric W. Biederman if (!error) 59777b14db5SEric W. Biederman error = res; 59877b14db5SEric W. Biederman out: 59977b14db5SEric W. Biederman sysctl_head_finish(head); 60077b14db5SEric W. Biederman 60177b14db5SEric W. Biederman return error; 60277b14db5SEric W. Biederman } 60377b14db5SEric W. Biederman 6047708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 6057708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 6067708bfb1SPavel Emelyanov { 6077708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 6087708bfb1SPavel Emelyanov } 6097708bfb1SPavel Emelyanov 61077b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 61177b14db5SEric W. Biederman size_t count, loff_t *ppos) 61277b14db5SEric W. Biederman { 6137708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 61477b14db5SEric W. Biederman } 61577b14db5SEric W. Biederman 616f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 617f1ecf068SLucas De Marchi { 6184e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 619f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 620f1ecf068SLucas De Marchi 6214e474a00SLucas De Marchi /* sysctl was unregistered */ 6224e474a00SLucas De Marchi if (IS_ERR(head)) 6234e474a00SLucas De Marchi return PTR_ERR(head); 6244e474a00SLucas De Marchi 625f1ecf068SLucas De Marchi if (table->poll) 626f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 627f1ecf068SLucas De Marchi 6284e474a00SLucas De Marchi sysctl_head_finish(head); 6294e474a00SLucas De Marchi 630f1ecf068SLucas De Marchi return 0; 631f1ecf068SLucas De Marchi } 632f1ecf068SLucas De Marchi 633076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 634f1ecf068SLucas De Marchi { 635496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6364e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 637f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 638076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6394e474a00SLucas De Marchi unsigned long event; 6404e474a00SLucas De Marchi 6414e474a00SLucas De Marchi /* sysctl was unregistered */ 6424e474a00SLucas De Marchi if (IS_ERR(head)) 643a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 644f1ecf068SLucas De Marchi 645f1ecf068SLucas De Marchi if (!table->proc_handler) 646f1ecf068SLucas De Marchi goto out; 647f1ecf068SLucas De Marchi 648f1ecf068SLucas De Marchi if (!table->poll) 649f1ecf068SLucas De Marchi goto out; 650f1ecf068SLucas De Marchi 6514e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 652f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 653f1ecf068SLucas De Marchi 654f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 655f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 656a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 657f1ecf068SLucas De Marchi } 658f1ecf068SLucas De Marchi 659f1ecf068SLucas De Marchi out: 6604e474a00SLucas De Marchi sysctl_head_finish(head); 6614e474a00SLucas De Marchi 662f1ecf068SLucas De Marchi return ret; 663f1ecf068SLucas De Marchi } 66477b14db5SEric W. Biederman 665f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 666f0c3b509SAl Viro struct dir_context *ctx, 6679043476fSAl Viro struct ctl_table_header *head, 6689043476fSAl Viro struct ctl_table *table) 66977b14db5SEric W. Biederman { 670f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 67177b14db5SEric W. Biederman struct inode *inode; 67277b14db5SEric W. Biederman struct qstr qname; 67377b14db5SEric W. Biederman ino_t ino = 0; 67477b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 67577b14db5SEric W. Biederman 67677b14db5SEric W. Biederman qname.name = table->procname; 67777b14db5SEric W. Biederman qname.len = strlen(table->procname); 6788387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 67977b14db5SEric W. Biederman 68077b14db5SEric W. Biederman child = d_lookup(dir, &qname); 68177b14db5SEric W. Biederman if (!child) { 68276aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 68376aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 68476aab3abSAl Viro if (IS_ERR(child)) 68576aab3abSAl Viro return false; 68676aab3abSAl Viro if (d_in_lookup(child)) { 6879043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 6889043476fSAl Viro if (!inode) { 68976aab3abSAl Viro d_lookup_done(child); 6909043476fSAl Viro dput(child); 691f0c3b509SAl Viro return false; 69276aab3abSAl Viro } 693fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 6949043476fSAl Viro d_add(child, inode); 69577b14db5SEric W. Biederman } 69677b14db5SEric W. Biederman } 6972b0143b5SDavid Howells inode = d_inode(child); 69877b14db5SEric W. Biederman ino = inode->i_ino; 69977b14db5SEric W. Biederman type = inode->i_mode >> 12; 70077b14db5SEric W. Biederman dput(child); 701f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7029043476fSAl Viro } 7039043476fSAl Viro 704f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 705f0c3b509SAl Viro struct dir_context *ctx, 7060e47c99dSEric W. Biederman struct ctl_table_header *head, 7070e47c99dSEric W. Biederman struct ctl_table *table) 7080e47c99dSEric W. Biederman { 709f0c3b509SAl Viro bool ret = true; 710a0b0d1c3SDanilo Krummrich 7110e47c99dSEric W. Biederman head = sysctl_head_grab(head); 712a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 713a0b0d1c3SDanilo Krummrich return false; 7140e47c99dSEric W. Biederman 7150e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 716835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7170e47c99dSEric W. Biederman goto out; 7180e47c99dSEric W. Biederman 719f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7200e47c99dSEric W. Biederman out: 7210e47c99dSEric W. Biederman sysctl_head_finish(head); 7220e47c99dSEric W. Biederman return ret; 7230e47c99dSEric W. Biederman } 7240e47c99dSEric W. Biederman 725e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7269043476fSAl Viro unsigned long *pos, struct file *file, 727f0c3b509SAl Viro struct dir_context *ctx) 7289043476fSAl Viro { 729f0c3b509SAl Viro bool res; 7309043476fSAl Viro 731f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 732f0c3b509SAl Viro return true; 7339043476fSAl Viro 7340e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 735f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7360e47c99dSEric W. Biederman else 737f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7389043476fSAl Viro 739f0c3b509SAl Viro if (res) 740f0c3b509SAl Viro ctx->pos = *pos; 7416a75ce16SEric W. Biederman 7426a75ce16SEric W. Biederman return res; 74377b14db5SEric W. Biederman } 74477b14db5SEric W. Biederman 745f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 74677b14db5SEric W. Biederman { 747f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7489043476fSAl Viro struct ctl_table_header *h = NULL; 7496a75ce16SEric W. Biederman struct ctl_table *entry; 7507ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 75177b14db5SEric W. Biederman unsigned long pos; 75277b14db5SEric W. Biederman 7539043476fSAl Viro if (IS_ERR(head)) 7549043476fSAl Viro return PTR_ERR(head); 7559043476fSAl Viro 7567ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 75777b14db5SEric W. Biederman 758f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 75993362fa4SZhou Chengming goto out; 760f0c3b509SAl Viro 76177b14db5SEric W. Biederman pos = 2; 76277b14db5SEric W. Biederman 7637ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 764f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7659043476fSAl Viro sysctl_head_finish(h); 7669043476fSAl Viro break; 76777b14db5SEric W. Biederman } 76877b14db5SEric W. Biederman } 76993362fa4SZhou Chengming out: 77077b14db5SEric W. Biederman sysctl_head_finish(head); 771f0c3b509SAl Viro return 0; 77277b14db5SEric W. Biederman } 77377b14db5SEric W. Biederman 77410556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 77577b14db5SEric W. Biederman { 77677b14db5SEric W. Biederman /* 77777b14db5SEric W. Biederman * sysctl entries that are not writeable, 77877b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 77977b14db5SEric W. Biederman */ 780f696a365SMiklos Szeredi struct ctl_table_header *head; 781f696a365SMiklos Szeredi struct ctl_table *table; 78277b14db5SEric W. Biederman int error; 78377b14db5SEric W. Biederman 784f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 785f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 786f696a365SMiklos Szeredi return -EACCES; 787f696a365SMiklos Szeredi 788f696a365SMiklos Szeredi head = grab_header(inode); 7899043476fSAl Viro if (IS_ERR(head)) 7909043476fSAl Viro return PTR_ERR(head); 79177b14db5SEric W. Biederman 792f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 7939043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 7949043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 7959043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 79673f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 7979043476fSAl Viro 79877b14db5SEric W. Biederman sysctl_head_finish(head); 79977b14db5SEric W. Biederman return error; 80077b14db5SEric W. Biederman } 80177b14db5SEric W. Biederman 80277b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 80377b14db5SEric W. Biederman { 8042b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 80577b14db5SEric W. Biederman int error; 80677b14db5SEric W. Biederman 80777b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 80877b14db5SEric W. Biederman return -EPERM; 80977b14db5SEric W. Biederman 81031051c85SJan Kara error = setattr_prepare(dentry, attr); 8111025774cSChristoph Hellwig if (error) 81277b14db5SEric W. Biederman return error; 8131025774cSChristoph Hellwig 8141025774cSChristoph Hellwig setattr_copy(inode, attr); 8151025774cSChristoph Hellwig mark_inode_dirty(inode); 8161025774cSChristoph Hellwig return 0; 81777b14db5SEric W. Biederman } 81877b14db5SEric W. Biederman 819a528d35eSDavid Howells static int proc_sys_getattr(const struct path *path, struct kstat *stat, 820a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8219043476fSAl Viro { 822a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8239043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8249043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8259043476fSAl Viro 8269043476fSAl Viro if (IS_ERR(head)) 8279043476fSAl Viro return PTR_ERR(head); 8289043476fSAl Viro 8299043476fSAl Viro generic_fillattr(inode, stat); 8309043476fSAl Viro if (table) 8319043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8329043476fSAl Viro 8339043476fSAl Viro sysctl_head_finish(head); 8349043476fSAl Viro return 0; 8359043476fSAl Viro } 8369043476fSAl Viro 83777b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 838f1ecf068SLucas De Marchi .open = proc_sys_open, 839f1ecf068SLucas De Marchi .poll = proc_sys_poll, 84077b14db5SEric W. Biederman .read = proc_sys_read, 84177b14db5SEric W. Biederman .write = proc_sys_write, 8426038f373SArnd Bergmann .llseek = default_llseek, 8439043476fSAl Viro }; 8449043476fSAl Viro 8459043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 846887df078SPavel Emelyanov .read = generic_read_dir, 847f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8483222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 84977b14db5SEric W. Biederman }; 85077b14db5SEric W. Biederman 85103a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8529043476fSAl Viro .permission = proc_sys_permission, 8539043476fSAl Viro .setattr = proc_sys_setattr, 8549043476fSAl Viro .getattr = proc_sys_getattr, 8559043476fSAl Viro }; 8569043476fSAl Viro 8579043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 85877b14db5SEric W. Biederman .lookup = proc_sys_lookup, 85977b14db5SEric W. Biederman .permission = proc_sys_permission, 86077b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8619043476fSAl Viro .getattr = proc_sys_getattr, 86277b14db5SEric W. Biederman }; 86377b14db5SEric W. Biederman 8640b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 86577b14db5SEric W. Biederman { 8660b728e19SAl Viro if (flags & LOOKUP_RCU) 86734286d66SNick Piggin return -ECHILD; 8682b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8699043476fSAl Viro } 8709043476fSAl Viro 871fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8729043476fSAl Viro { 8732b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 8749043476fSAl Viro } 8759043476fSAl Viro 8761f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8771f87f0b5SEric W. Biederman { 8781f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8791f87f0b5SEric W. Biederman int res; 8801f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8811f87f0b5SEric W. Biederman if (p->unregistering) 8821f87f0b5SEric W. Biederman res = 0; 8831f87f0b5SEric W. Biederman else if (!set->is_seen) 8841f87f0b5SEric W. Biederman res = 1; 8851f87f0b5SEric W. Biederman else 8861f87f0b5SEric W. Biederman res = set->is_seen(set); 8871f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 8881f87f0b5SEric W. Biederman return res; 8891f87f0b5SEric W. Biederman } 8901f87f0b5SEric W. Biederman 8916fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 892621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 8939043476fSAl Viro { 894dfef6dcdSAl Viro struct ctl_table_header *head; 895da53be12SLinus Torvalds struct inode *inode; 896da53be12SLinus Torvalds 89731e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 89831e6b01fSNick Piggin * that inode here can be NULL */ 899dfef6dcdSAl Viro /* AV: can it, indeed? */ 9002b0143b5SDavid Howells inode = d_inode_rcu(dentry); 90131e6b01fSNick Piggin if (!inode) 902dfef6dcdSAl Viro return 1; 903621e155aSNick Piggin if (name->len != len) 9049043476fSAl Viro return 1; 905621e155aSNick Piggin if (memcmp(name->name, str, len)) 9069043476fSAl Viro return 1; 907dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 908dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 90977b14db5SEric W. Biederman } 91077b14db5SEric W. Biederman 911d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 91277b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9139043476fSAl Viro .d_delete = proc_sys_delete, 9149043476fSAl Viro .d_compare = proc_sys_compare, 91577b14db5SEric W. Biederman }; 91677b14db5SEric W. Biederman 9170e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9187ec66d06SEric W. Biederman const char *name, int namelen) 9191f87f0b5SEric W. Biederman { 9207ec66d06SEric W. Biederman struct ctl_table_header *head; 9217ec66d06SEric W. Biederman struct ctl_table *entry; 9221f87f0b5SEric W. Biederman 9230e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9247ec66d06SEric W. Biederman if (!entry) 9257ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 92651f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9277ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 92851f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9291f87f0b5SEric W. Biederman } 9301f87f0b5SEric W. Biederman 9317ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9327ec66d06SEric W. Biederman const char *name, int namelen) 9331f87f0b5SEric W. Biederman { 9347ec66d06SEric W. Biederman struct ctl_table *table; 9357ec66d06SEric W. Biederman struct ctl_dir *new; 936ac13ac6fSEric W. Biederman struct ctl_node *node; 9377ec66d06SEric W. Biederman char *new_name; 9381f87f0b5SEric W. Biederman 939ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 940ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 941ac13ac6fSEric W. Biederman GFP_KERNEL); 9427ec66d06SEric W. Biederman if (!new) 9437ec66d06SEric W. Biederman return NULL; 9447ec66d06SEric W. Biederman 945ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 946ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9477ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9487ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9497ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9507ec66d06SEric W. Biederman table[0].procname = new_name; 9517ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 952ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9537ec66d06SEric W. Biederman 9547ec66d06SEric W. Biederman return new; 9551f87f0b5SEric W. Biederman } 9561f87f0b5SEric W. Biederman 95760f126d9SEric W. Biederman /** 95860f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 95960f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 96060f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 96160f126d9SEric W. Biederman * @namelen: The length of name 96260f126d9SEric W. Biederman * 96360f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 96460f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 96560f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 96660f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 96760f126d9SEric W. Biederman * simply dropped. 96860f126d9SEric W. Biederman */ 9690e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9700e47c99dSEric W. Biederman const char *name, int namelen) 9717ec66d06SEric W. Biederman { 9720e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9737ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9740eb97f38SEric W. Biederman int err; 9757ec66d06SEric W. Biederman 9767ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9770e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9787ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9797ec66d06SEric W. Biederman goto found; 9807ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9817ec66d06SEric W. Biederman goto failed; 9827ec66d06SEric W. Biederman 9837ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9847ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 9857ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9867ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 9877ec66d06SEric W. Biederman if (!new) 9887ec66d06SEric W. Biederman goto failed; 9897ec66d06SEric W. Biederman 99060f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 9910e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9927ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9937ec66d06SEric W. Biederman goto found; 9947ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9957ec66d06SEric W. Biederman goto failed; 9967ec66d06SEric W. Biederman 99760f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 9980eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 9990eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10000eb97f38SEric W. Biederman if (err) 10010e47c99dSEric W. Biederman goto failed; 10027ec66d06SEric W. Biederman subdir = new; 10037ec66d06SEric W. Biederman found: 10047ec66d06SEric W. Biederman subdir->header.nreg++; 10057ec66d06SEric W. Biederman failed: 1006a1c83681SViresh Kumar if (IS_ERR(subdir)) { 100787ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10086980128fSEric W. Biederman sysctl_print_dir(dir); 100987ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 10107ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 10111f87f0b5SEric W. Biederman } 10127ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10137ec66d06SEric W. Biederman if (new) 10147ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10157ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10167ec66d06SEric W. Biederman return subdir; 10171f87f0b5SEric W. Biederman } 10181f87f0b5SEric W. Biederman 10190e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10200e47c99dSEric W. Biederman { 10210e47c99dSEric W. Biederman struct ctl_dir *parent; 10220e47c99dSEric W. Biederman const char *procname; 10230e47c99dSEric W. Biederman if (!dir->header.parent) 10240e47c99dSEric W. Biederman return &set->dir; 10250e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10260e47c99dSEric W. Biederman if (IS_ERR(parent)) 10270e47c99dSEric W. Biederman return parent; 10280e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10290e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10300e47c99dSEric W. Biederman } 10310e47c99dSEric W. Biederman 10320e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 103313bcc6a2SEric W. Biederman struct ctl_table **pentry) 10340e47c99dSEric W. Biederman { 10350e47c99dSEric W. Biederman struct ctl_table_header *head; 10360e47c99dSEric W. Biederman struct ctl_table_root *root; 10370e47c99dSEric W. Biederman struct ctl_table_set *set; 10380e47c99dSEric W. Biederman struct ctl_table *entry; 10390e47c99dSEric W. Biederman struct ctl_dir *dir; 10400e47c99dSEric W. Biederman int ret; 10410e47c99dSEric W. Biederman 10420e47c99dSEric W. Biederman ret = 0; 10430e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10440e47c99dSEric W. Biederman root = (*pentry)->data; 104513bcc6a2SEric W. Biederman set = lookup_header_set(root); 10460e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10470e47c99dSEric W. Biederman if (IS_ERR(dir)) 10480e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10490e47c99dSEric W. Biederman else { 10500e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10510e47c99dSEric W. Biederman head = NULL; 10520e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10530e47c99dSEric W. Biederman ret = -ENOENT; 10540e47c99dSEric W. Biederman if (entry && use_table(head)) { 10550e47c99dSEric W. Biederman unuse_table(*phead); 10560e47c99dSEric W. Biederman *phead = head; 10570e47c99dSEric W. Biederman *pentry = entry; 10580e47c99dSEric W. Biederman ret = 0; 10590e47c99dSEric W. Biederman } 10600e47c99dSEric W. Biederman } 10610e47c99dSEric W. Biederman 10620e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10630e47c99dSEric W. Biederman return ret; 10640e47c99dSEric W. Biederman } 10650e47c99dSEric W. Biederman 10667c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10677c60c48fSEric W. Biederman { 10687c60c48fSEric W. Biederman struct va_format vaf; 10697c60c48fSEric W. Biederman va_list args; 10707c60c48fSEric W. Biederman 10717c60c48fSEric W. Biederman va_start(args, fmt); 10727c60c48fSEric W. Biederman vaf.fmt = fmt; 10737c60c48fSEric W. Biederman vaf.va = &args; 10747c60c48fSEric W. Biederman 107587ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10767c60c48fSEric W. Biederman path, table->procname, &vaf); 10777c60c48fSEric W. Biederman 10787c60c48fSEric W. Biederman va_end(args); 10797c60c48fSEric W. Biederman return -EINVAL; 10807c60c48fSEric W. Biederman } 10817c60c48fSEric W. Biederman 10824f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 10834f2fec00SLuis R. Rodriguez { 10844f2fec00SLuis R. Rodriguez int err = 0; 10854f2fec00SLuis R. Rodriguez 108661d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 108761d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 10884f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 10894f2fec00SLuis R. Rodriguez err |= sysctl_err(path, table, "array now allowed"); 10904f2fec00SLuis R. Rodriguez } 10914f2fec00SLuis R. Rodriguez 10924f2fec00SLuis R. Rodriguez return err; 10934f2fec00SLuis R. Rodriguez } 10944f2fec00SLuis R. Rodriguez 10957c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 10967c60c48fSEric W. Biederman { 10977c60c48fSEric W. Biederman int err = 0; 10987c60c48fSEric W. Biederman for (; table->procname; table++) { 10997c60c48fSEric W. Biederman if (table->child) 110089c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "Not a file"); 11017c60c48fSEric W. Biederman 11021f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 11031f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 11041680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 110561d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax) || 11061f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 11071f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 11081f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 11091f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 11101f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 11111f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 11121f87f0b5SEric W. Biederman if (!table->data) 111389c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No data"); 11141f87f0b5SEric W. Biederman if (!table->maxlen) 111589c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No maxlen"); 11164f2fec00SLuis R. Rodriguez else 11174f2fec00SLuis R. Rodriguez err |= sysctl_check_table_array(path, table); 11181f87f0b5SEric W. Biederman } 11191f87f0b5SEric W. Biederman if (!table->proc_handler) 112089c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No proc_handler"); 11217c60c48fSEric W. Biederman 11227c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 112389c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "bogus .mode 0%o", 11247c60c48fSEric W. Biederman table->mode); 11251f87f0b5SEric W. Biederman } 11267c60c48fSEric W. Biederman return err; 11271f87f0b5SEric W. Biederman } 11281f87f0b5SEric W. Biederman 11290e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11300e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11310e47c99dSEric W. Biederman { 11320e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11330e47c99dSEric W. Biederman struct ctl_table_header *links; 1134ac13ac6fSEric W. Biederman struct ctl_node *node; 11350e47c99dSEric W. Biederman char *link_name; 11360e47c99dSEric W. Biederman int nr_entries, name_bytes; 11370e47c99dSEric W. Biederman 11380e47c99dSEric W. Biederman name_bytes = 0; 11390e47c99dSEric W. Biederman nr_entries = 0; 11400e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11410e47c99dSEric W. Biederman nr_entries++; 11420e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11430e47c99dSEric W. Biederman } 11440e47c99dSEric W. Biederman 11450e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1146ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11470e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11480e47c99dSEric W. Biederman name_bytes, 11490e47c99dSEric W. Biederman GFP_KERNEL); 11500e47c99dSEric W. Biederman 11510e47c99dSEric W. Biederman if (!links) 11520e47c99dSEric W. Biederman return NULL; 11530e47c99dSEric W. Biederman 1154ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1155ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11560e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11570e47c99dSEric W. Biederman 11580e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11590e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11600e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11610e47c99dSEric W. Biederman link->procname = link_name; 11620e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11630e47c99dSEric W. Biederman link->data = link_root; 11640e47c99dSEric W. Biederman link_name += len; 11650e47c99dSEric W. Biederman } 1166ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11670e47c99dSEric W. Biederman links->nreg = nr_entries; 11680e47c99dSEric W. Biederman 11690e47c99dSEric W. Biederman return links; 11700e47c99dSEric W. Biederman } 11710e47c99dSEric W. Biederman 11720e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11730e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11740e47c99dSEric W. Biederman { 11750e47c99dSEric W. Biederman struct ctl_table_header *head; 11760e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11770e47c99dSEric W. Biederman 11780e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11790e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11800e47c99dSEric W. Biederman const char *procname = entry->procname; 11810e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11820e47c99dSEric W. Biederman if (!link) 11830e47c99dSEric W. Biederman return false; 11840e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 11850e47c99dSEric W. Biederman continue; 11860e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 11870e47c99dSEric W. Biederman continue; 11880e47c99dSEric W. Biederman return false; 11890e47c99dSEric W. Biederman } 11900e47c99dSEric W. Biederman 11910e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 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 head->nreg++; 11960e47c99dSEric W. Biederman } 11970e47c99dSEric W. Biederman return true; 11980e47c99dSEric W. Biederman } 11990e47c99dSEric W. Biederman 12000e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12010e47c99dSEric W. Biederman { 12020e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12030e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 12040e47c99dSEric W. Biederman struct ctl_table_header *links; 12050e47c99dSEric W. Biederman int err; 12060e47c99dSEric W. Biederman 12070e47c99dSEric W. Biederman if (head->set == root_set) 12080e47c99dSEric W. Biederman return 0; 12090e47c99dSEric W. Biederman 12100e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12110e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12120e47c99dSEric W. Biederman return 0; 12130e47c99dSEric W. Biederman 12140e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12150e47c99dSEric W. Biederman return 0; 12160e47c99dSEric W. Biederman 12170e47c99dSEric W. Biederman core_parent->header.nreg++; 12180e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12190e47c99dSEric W. Biederman 12200e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12210e47c99dSEric W. Biederman 12220e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12230e47c99dSEric W. Biederman err = -ENOMEM; 12240e47c99dSEric W. Biederman if (!links) 12250e47c99dSEric W. Biederman goto out; 12260e47c99dSEric W. Biederman 12270e47c99dSEric W. Biederman err = 0; 12280e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12290e47c99dSEric W. Biederman kfree(links); 12300e47c99dSEric W. Biederman goto out; 12310e47c99dSEric W. Biederman } 12320e47c99dSEric W. Biederman 12330e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12340e47c99dSEric W. Biederman if (err) 12350e47c99dSEric W. Biederman kfree(links); 12360e47c99dSEric W. Biederman out: 12370e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12380e47c99dSEric W. Biederman return err; 12390e47c99dSEric W. Biederman } 12400e47c99dSEric W. Biederman 12411f87f0b5SEric W. Biederman /** 1242f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 124360a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12441f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12451f87f0b5SEric W. Biederman * @table: the top-level table structure 12461f87f0b5SEric W. Biederman * 12471f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12481f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12491f87f0b5SEric W. Biederman * 12501f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12511f87f0b5SEric W. Biederman * 12521f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12531f87f0b5SEric W. Biederman * enter a sysctl file 12541f87f0b5SEric W. Biederman * 12551f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12561f87f0b5SEric W. Biederman * 12571f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12581f87f0b5SEric W. Biederman * 1259f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12601f87f0b5SEric W. Biederman * 1261f728019bSEric W. Biederman * child - must be %NULL. 12621f87f0b5SEric W. Biederman * 12631f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12641f87f0b5SEric W. Biederman * 12651f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12661f87f0b5SEric W. Biederman * 12671f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12681f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12691f87f0b5SEric W. Biederman * 1270f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1271f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12721f87f0b5SEric W. Biederman * 12731f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12741f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12751f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12761f87f0b5SEric W. Biederman * 12771f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12781f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12791f87f0b5SEric W. Biederman * 12801f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 12811f87f0b5SEric W. Biederman * to the table header on success. 12821f87f0b5SEric W. Biederman */ 12836e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 128460a47a2eSEric W. Biederman struct ctl_table_set *set, 12856e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 12861f87f0b5SEric W. Biederman { 128760a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 12881f87f0b5SEric W. Biederman struct ctl_table_header *header; 12896e9d5164SEric W. Biederman const char *name, *nextname; 12907ec66d06SEric W. Biederman struct ctl_dir *dir; 1291ac13ac6fSEric W. Biederman struct ctl_table *entry; 1292ac13ac6fSEric W. Biederman struct ctl_node *node; 1293ac13ac6fSEric W. Biederman int nr_entries = 0; 12941f87f0b5SEric W. Biederman 1295ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1296ac13ac6fSEric W. Biederman nr_entries++; 1297ac13ac6fSEric W. Biederman 1298ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1299ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 13001f87f0b5SEric W. Biederman if (!header) 13011f87f0b5SEric W. Biederman return NULL; 13021f87f0b5SEric W. Biederman 1303ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1304ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13057c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13067c60c48fSEric W. Biederman goto fail; 13078d6ecfccSEric W. Biederman 13081f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13090e47c99dSEric W. Biederman dir = &set->dir; 131060f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 13117ec66d06SEric W. Biederman dir->header.nreg++; 13127ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13137ec66d06SEric W. Biederman 13147ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 13157ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 13167ec66d06SEric W. Biederman int namelen; 13177ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13187ec66d06SEric W. Biederman if (nextname) { 13197ec66d06SEric W. Biederman namelen = nextname - name; 13207ec66d06SEric W. Biederman nextname++; 13217ec66d06SEric W. Biederman } else { 13227ec66d06SEric W. Biederman namelen = strlen(name); 13237ec66d06SEric W. Biederman } 13247ec66d06SEric W. Biederman if (namelen == 0) 13251f87f0b5SEric W. Biederman continue; 13267ec66d06SEric W. Biederman 13270e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13287ec66d06SEric W. Biederman if (IS_ERR(dir)) 13297ec66d06SEric W. Biederman goto fail; 13301f87f0b5SEric W. Biederman } 13310e47c99dSEric W. Biederman 13327ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13330e47c99dSEric W. Biederman if (insert_header(dir, header)) 13340e47c99dSEric W. Biederman goto fail_put_dir_locked; 13350e47c99dSEric W. Biederman 13367ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13371f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13381f87f0b5SEric W. Biederman 13391f87f0b5SEric W. Biederman return header; 13400e47c99dSEric W. Biederman 13417ec66d06SEric W. Biederman fail_put_dir_locked: 13427ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13437c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13447c60c48fSEric W. Biederman fail: 13457c60c48fSEric W. Biederman kfree(header); 13467c60c48fSEric W. Biederman dump_stack(); 13477c60c48fSEric W. Biederman return NULL; 13481f87f0b5SEric W. Biederman } 13491f87f0b5SEric W. Biederman 1350fea478d4SEric W. Biederman /** 1351fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1352fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1353fea478d4SEric W. Biederman * @table: the table structure 1354fea478d4SEric W. Biederman * 1355fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1356fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1357fea478d4SEric W. Biederman * 1358fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1359fea478d4SEric W. Biederman */ 1360fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1361fea478d4SEric W. Biederman { 1362fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1363fea478d4SEric W. Biederman path, table); 1364fea478d4SEric W. Biederman } 1365fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1366fea478d4SEric W. Biederman 13676e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 13686e9d5164SEric W. Biederman { 13696e9d5164SEric W. Biederman int namelen; 13706e9d5164SEric W. Biederman namelen = strlen(name); 13716e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 13726e9d5164SEric W. Biederman return NULL; 13736e9d5164SEric W. Biederman memcpy(pos, name, namelen); 13746e9d5164SEric W. Biederman pos[namelen] = '/'; 13756e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 13766e9d5164SEric W. Biederman pos += namelen + 1; 13776e9d5164SEric W. Biederman return pos; 13786e9d5164SEric W. Biederman } 13796e9d5164SEric W. Biederman 1380f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1381f728019bSEric W. Biederman { 1382f728019bSEric W. Biederman int has_files = 0; 1383f728019bSEric W. Biederman int nr_subheaders = 0; 1384f728019bSEric W. Biederman struct ctl_table *entry; 1385f728019bSEric W. Biederman 1386f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1387f728019bSEric W. Biederman if (!table || !table->procname) 1388f728019bSEric W. Biederman return 1; 1389f728019bSEric W. Biederman 1390f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1391f728019bSEric W. Biederman if (entry->child) 1392f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1393f728019bSEric W. Biederman else 1394f728019bSEric W. Biederman has_files = 1; 1395f728019bSEric W. Biederman } 1396f728019bSEric W. Biederman return nr_subheaders + has_files; 1397f728019bSEric W. Biederman } 1398f728019bSEric W. Biederman 1399f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 140060a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1401f728019bSEric W. Biederman struct ctl_table *table) 1402f728019bSEric W. Biederman { 1403f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1404f728019bSEric W. Biederman struct ctl_table *entry, *files; 1405f728019bSEric W. Biederman int nr_files = 0; 1406f728019bSEric W. Biederman int nr_dirs = 0; 1407f728019bSEric W. Biederman int err = -ENOMEM; 1408f728019bSEric W. Biederman 1409f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1410f728019bSEric W. Biederman if (entry->child) 1411f728019bSEric W. Biederman nr_dirs++; 1412f728019bSEric W. Biederman else 1413f728019bSEric W. Biederman nr_files++; 1414f728019bSEric W. Biederman } 1415f728019bSEric W. Biederman 1416f728019bSEric W. Biederman files = table; 1417f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1418f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1419f728019bSEric W. Biederman struct ctl_table *new; 1420f728019bSEric W. Biederman files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), 1421f728019bSEric W. Biederman GFP_KERNEL); 1422f728019bSEric W. Biederman if (!files) 1423f728019bSEric W. Biederman goto out; 1424f728019bSEric W. Biederman 1425f728019bSEric W. Biederman ctl_table_arg = files; 1426f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1427f728019bSEric W. Biederman if (entry->child) 1428f728019bSEric W. Biederman continue; 1429f728019bSEric W. Biederman *new = *entry; 1430f728019bSEric W. Biederman new++; 1431f728019bSEric W. Biederman } 1432f728019bSEric W. Biederman } 1433f728019bSEric W. Biederman 1434f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1435f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1436f728019bSEric W. Biederman struct ctl_table_header *header; 143760a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1438f728019bSEric W. Biederman if (!header) { 1439f728019bSEric W. Biederman kfree(ctl_table_arg); 1440f728019bSEric W. Biederman goto out; 1441f728019bSEric W. Biederman } 1442f728019bSEric W. Biederman 1443f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1444f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1445f728019bSEric W. Biederman **subheader = header; 1446f728019bSEric W. Biederman (*subheader)++; 1447f728019bSEric W. Biederman } 1448f728019bSEric W. Biederman 1449f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1450f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1451f728019bSEric W. Biederman char *child_pos; 1452f728019bSEric W. Biederman 1453f728019bSEric W. Biederman if (!entry->child) 1454f728019bSEric W. Biederman continue; 1455f728019bSEric W. Biederman 1456f728019bSEric W. Biederman err = -ENAMETOOLONG; 1457f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1458f728019bSEric W. Biederman if (!child_pos) 1459f728019bSEric W. Biederman goto out; 1460f728019bSEric W. Biederman 1461f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 146260a47a2eSEric W. Biederman set, entry->child); 1463f728019bSEric W. Biederman pos[0] = '\0'; 1464f728019bSEric W. Biederman if (err) 1465f728019bSEric W. Biederman goto out; 1466f728019bSEric W. Biederman } 1467f728019bSEric W. Biederman err = 0; 1468f728019bSEric W. Biederman out: 1469f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1470f728019bSEric W. Biederman return err; 1471f728019bSEric W. Biederman } 1472f728019bSEric W. Biederman 14736e9d5164SEric W. Biederman /** 14746e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 147560a47a2eSEric W. Biederman * @set: Sysctl tree to register on 14766e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14776e9d5164SEric W. Biederman * @table: the top-level table structure 14786e9d5164SEric W. Biederman * 14796e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14806e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14816e9d5164SEric W. Biederman * 14826e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 14836e9d5164SEric W. Biederman */ 14846e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 148560a47a2eSEric W. Biederman struct ctl_table_set *set, 14866e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 14876e9d5164SEric W. Biederman { 1488ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1489f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1490f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 14916e9d5164SEric W. Biederman const struct ctl_path *component; 14926e9d5164SEric W. Biederman char *new_path, *pos; 14936e9d5164SEric W. Biederman 14946e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 14956e9d5164SEric W. Biederman if (!new_path) 14966e9d5164SEric W. Biederman return NULL; 14976e9d5164SEric W. Biederman 14986e9d5164SEric W. Biederman pos[0] = '\0'; 14996e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15006e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15016e9d5164SEric W. Biederman if (!pos) 15026e9d5164SEric W. Biederman goto out; 15036e9d5164SEric W. Biederman } 1504ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1505ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1506ec6a5266SEric W. Biederman if (!pos) 1507ec6a5266SEric W. Biederman goto out; 1508ec6a5266SEric W. Biederman table = table->child; 1509ec6a5266SEric W. Biederman } 1510f728019bSEric W. Biederman if (nr_subheaders == 1) { 151160a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1512ec6a5266SEric W. Biederman if (header) 1513ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1514f728019bSEric W. Biederman } else { 1515f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1516f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1517f728019bSEric W. Biederman if (!header) 1518f728019bSEric W. Biederman goto out; 1519f728019bSEric W. Biederman 1520f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1521f728019bSEric W. Biederman subheader = subheaders; 1522f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1523f728019bSEric W. Biederman 1524f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 152560a47a2eSEric W. Biederman set, table)) 1526f728019bSEric W. Biederman goto err_register_leaves; 1527f728019bSEric W. Biederman } 1528f728019bSEric W. Biederman 15296e9d5164SEric W. Biederman out: 15306e9d5164SEric W. Biederman kfree(new_path); 15316e9d5164SEric W. Biederman return header; 1532f728019bSEric W. Biederman 1533f728019bSEric W. Biederman err_register_leaves: 1534f728019bSEric W. Biederman while (subheader > subheaders) { 1535f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1536f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1537f728019bSEric W. Biederman unregister_sysctl_table(subh); 1538f728019bSEric W. Biederman kfree(table); 1539f728019bSEric W. Biederman } 1540f728019bSEric W. Biederman kfree(header); 1541f728019bSEric W. Biederman header = NULL; 1542f728019bSEric W. Biederman goto out; 15436e9d5164SEric W. Biederman } 15446e9d5164SEric W. Biederman 15451f87f0b5SEric W. Biederman /** 15461f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 15471f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15481f87f0b5SEric W. Biederman * @table: the top-level table structure 15491f87f0b5SEric W. Biederman * 15501f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15511f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15521f87f0b5SEric W. Biederman * 15531f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 15541f87f0b5SEric W. Biederman */ 15551f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 15561f87f0b5SEric W. Biederman struct ctl_table *table) 15571f87f0b5SEric W. Biederman { 155860a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 15591f87f0b5SEric W. Biederman path, table); 15601f87f0b5SEric W. Biederman } 15611f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 15621f87f0b5SEric W. Biederman 15631f87f0b5SEric W. Biederman /** 15641f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 15651f87f0b5SEric W. Biederman * @table: the top-level table structure 15661f87f0b5SEric W. Biederman * 15671f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15681f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15691f87f0b5SEric W. Biederman * 15701f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 15711f87f0b5SEric W. Biederman */ 15721f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 15731f87f0b5SEric W. Biederman { 15741f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 15751f87f0b5SEric W. Biederman 15761f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 15771f87f0b5SEric W. Biederman } 15781f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 15791f87f0b5SEric W. Biederman 15800e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 15810e47c99dSEric W. Biederman { 15820e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 15830e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 15840e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 15850e47c99dSEric W. Biederman struct ctl_dir *core_parent; 15860e47c99dSEric W. Biederman struct ctl_table *entry; 15870e47c99dSEric W. Biederman 15880e47c99dSEric W. Biederman if (header->set == root_set) 15890e47c99dSEric W. Biederman return; 15900e47c99dSEric W. Biederman 15910e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 15920e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 15930e47c99dSEric W. Biederman return; 15940e47c99dSEric W. Biederman 15950e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 15960e47c99dSEric W. Biederman struct ctl_table_header *link_head; 15970e47c99dSEric W. Biederman struct ctl_table *link; 15980e47c99dSEric W. Biederman const char *name = entry->procname; 15990e47c99dSEric W. Biederman 16000e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 16010e47c99dSEric W. Biederman if (link && 16020e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 16030e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 16040e47c99dSEric W. Biederman drop_sysctl_table(link_head); 16050e47c99dSEric W. Biederman } 16060e47c99dSEric W. Biederman else { 160787ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 16080e47c99dSEric W. Biederman sysctl_print_dir(parent); 160987ebdc00SAndrew Morton pr_cont("/%s\n", name); 16100e47c99dSEric W. Biederman } 16110e47c99dSEric W. Biederman } 16120e47c99dSEric W. Biederman } 16130e47c99dSEric W. Biederman 1614938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1615938aaa4fSEric W. Biederman { 16167ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 16177ec66d06SEric W. Biederman 1618938aaa4fSEric W. Biederman if (--header->nreg) 1619938aaa4fSEric W. Biederman return; 1620938aaa4fSEric W. Biederman 16210e47c99dSEric W. Biederman put_links(header); 1622938aaa4fSEric W. Biederman start_unregistering(header); 1623938aaa4fSEric W. Biederman if (!--header->count) 1624938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16257ec66d06SEric W. Biederman 16267ec66d06SEric W. Biederman if (parent) 16277ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1628938aaa4fSEric W. Biederman } 1629938aaa4fSEric W. Biederman 16301f87f0b5SEric W. Biederman /** 16311f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16321f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16331f87f0b5SEric W. Biederman * 16341f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16351f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16361f87f0b5SEric W. Biederman */ 16371f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16381f87f0b5SEric W. Biederman { 1639f728019bSEric W. Biederman int nr_subheaders; 16401f87f0b5SEric W. Biederman might_sleep(); 16411f87f0b5SEric W. Biederman 16421f87f0b5SEric W. Biederman if (header == NULL) 16431f87f0b5SEric W. Biederman return; 16441f87f0b5SEric W. Biederman 1645f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1646f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1647f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1648f728019bSEric W. Biederman int i; 1649f728019bSEric W. Biederman 1650f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1651f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1652f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1653f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1654f728019bSEric W. Biederman unregister_sysctl_table(subh); 1655f728019bSEric W. Biederman kfree(table); 1656f728019bSEric W. Biederman } 1657f728019bSEric W. Biederman kfree(header); 1658f728019bSEric W. Biederman return; 1659f728019bSEric W. Biederman } 1660f728019bSEric W. Biederman 16611f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1662938aaa4fSEric W. Biederman drop_sysctl_table(header); 16631f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 16641f87f0b5SEric W. Biederman } 16651f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 16661f87f0b5SEric W. Biederman 16670e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 16689eb47c26SEric W. Biederman struct ctl_table_root *root, 16691f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 16701f87f0b5SEric W. Biederman { 16711347440dSDan Carpenter memset(set, 0, sizeof(*set)); 16720e47c99dSEric W. Biederman set->is_seen = is_seen; 1673ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 16741f87f0b5SEric W. Biederman } 16751f87f0b5SEric W. Biederman 167697324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 167797324cd8SEric W. Biederman { 1678ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 167997324cd8SEric W. Biederman } 16801f87f0b5SEric W. Biederman 16811e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 168277b14db5SEric W. Biederman { 1683e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1684e1675231SAlexey Dobriyan 168577b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 16869043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 16879043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 168877b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1689de4e83bdSEric W. Biederman 1690de4e83bdSEric W. Biederman return sysctl_init(); 169177b14db5SEric W. Biederman } 1692