diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/proc/proc_sysctl.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/proc/proc_sysctl.c | 1606 |
1 files changed, 0 insertions, 1606 deletions
diff --git a/ANDROID_3.4.5/fs/proc/proc_sysctl.c b/ANDROID_3.4.5/fs/proc/proc_sysctl.c deleted file mode 100644 index 21d836f4..00000000 --- a/ANDROID_3.4.5/fs/proc/proc_sysctl.c +++ /dev/null @@ -1,1606 +0,0 @@ -/* - * /proc/sys support - */ -#include <linux/init.h> -#include <linux/sysctl.h> -#include <linux/poll.h> -#include <linux/proc_fs.h> -#include <linux/security.h> -#include <linux/sched.h> -#include <linux/namei.h> -#include <linux/mm.h> -#include <linux/module.h> -#include "internal.h" - -static const struct dentry_operations proc_sys_dentry_operations; -static const struct file_operations proc_sys_file_operations; -static const struct inode_operations proc_sys_inode_operations; -static const struct file_operations proc_sys_dir_file_operations; -static const struct inode_operations proc_sys_dir_operations; - -void proc_sys_poll_notify(struct ctl_table_poll *poll) -{ - if (!poll) - return; - - atomic_inc(&poll->event); - wake_up_interruptible(&poll->wait); -} - -static struct ctl_table root_table[] = { - { - .procname = "", - .mode = S_IFDIR|S_IRUGO|S_IXUGO, - }, - { } -}; -static struct ctl_table_root sysctl_table_root = { - .default_set.dir.header = { - {{.count = 1, - .nreg = 1, - .ctl_table = root_table }}, - .ctl_table_arg = root_table, - .root = &sysctl_table_root, - .set = &sysctl_table_root.default_set, - }, -}; - -static DEFINE_SPINLOCK(sysctl_lock); - -static void drop_sysctl_table(struct ctl_table_header *header); -static int sysctl_follow_link(struct ctl_table_header **phead, - struct ctl_table **pentry, struct nsproxy *namespaces); -static int insert_links(struct ctl_table_header *head); -static void put_links(struct ctl_table_header *header); - -static void sysctl_print_dir(struct ctl_dir *dir) -{ - if (dir->header.parent) - sysctl_print_dir(dir->header.parent); - printk(KERN_CONT "%s/", dir->header.ctl_table[0].procname); -} - -static int namecmp(const char *name1, int len1, const char *name2, int len2) -{ - int minlen; - int cmp; - - minlen = len1; - if (minlen > len2) - minlen = len2; - - cmp = memcmp(name1, name2, minlen); - if (cmp == 0) - cmp = len1 - len2; - return cmp; -} - -/* Called under sysctl_lock */ -static struct ctl_table *find_entry(struct ctl_table_header **phead, - struct ctl_dir *dir, const char *name, int namelen) -{ - struct ctl_table_header *head; - struct ctl_table *entry; - struct rb_node *node = dir->root.rb_node; - - while (node) - { - struct ctl_node *ctl_node; - const char *procname; - int cmp; - - ctl_node = rb_entry(node, struct ctl_node, node); - head = ctl_node->header; - entry = &head->ctl_table[ctl_node - head->node]; - procname = entry->procname; - - cmp = namecmp(name, namelen, procname, strlen(procname)); - if (cmp < 0) - node = node->rb_left; - else if (cmp > 0) - node = node->rb_right; - else { - *phead = head; - return entry; - } - } - return NULL; -} - -static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) -{ - struct rb_node *node = &head->node[entry - head->ctl_table].node; - struct rb_node **p = &head->parent->root.rb_node; - struct rb_node *parent = NULL; - const char *name = entry->procname; - int namelen = strlen(name); - - while (*p) { - struct ctl_table_header *parent_head; - struct ctl_table *parent_entry; - struct ctl_node *parent_node; - const char *parent_name; - int cmp; - - parent = *p; - parent_node = rb_entry(parent, struct ctl_node, node); - parent_head = parent_node->header; - parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; - parent_name = parent_entry->procname; - - cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); - if (cmp < 0) - p = &(*p)->rb_left; - else if (cmp > 0) - p = &(*p)->rb_right; - else { - printk(KERN_ERR "sysctl duplicate entry: "); - sysctl_print_dir(head->parent); - printk(KERN_CONT "/%s\n", entry->procname); - return -EEXIST; - } - } - - rb_link_node(node, parent, p); - return 0; -} - -static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) -{ - struct rb_node *node = &head->node[entry - head->ctl_table].node; - - rb_erase(node, &head->parent->root); -} - -static void init_header(struct ctl_table_header *head, - struct ctl_table_root *root, struct ctl_table_set *set, - struct ctl_node *node, struct ctl_table *table) -{ - head->ctl_table = table; - head->ctl_table_arg = table; - head->used = 0; - head->count = 1; - head->nreg = 1; - head->unregistering = NULL; - head->root = root; - head->set = set; - head->parent = NULL; - head->node = node; - if (node) { - struct ctl_table *entry; - for (entry = table; entry->procname; entry++, node++) { - rb_init_node(&node->node); - node->header = head; - } - } -} - -static void erase_header(struct ctl_table_header *head) -{ - struct ctl_table *entry; - for (entry = head->ctl_table; entry->procname; entry++) - erase_entry(head, entry); -} - -static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) -{ - struct ctl_table *entry; - int err; - - dir->header.nreg++; - header->parent = dir; - err = insert_links(header); - if (err) - goto fail_links; - for (entry = header->ctl_table; entry->procname; entry++) { - err = insert_entry(header, entry); - if (err) - goto fail; - } - return 0; -fail: - erase_header(header); - put_links(header); -fail_links: - header->parent = NULL; - drop_sysctl_table(&dir->header); - return err; -} - -/* called under sysctl_lock */ -static int use_table(struct ctl_table_header *p) -{ - if (unlikely(p->unregistering)) - return 0; - p->used++; - return 1; -} - -/* called under sysctl_lock */ -static void unuse_table(struct ctl_table_header *p) -{ - if (!--p->used) - if (unlikely(p->unregistering)) - complete(p->unregistering); -} - -/* called under sysctl_lock, will reacquire if has to wait */ -static void start_unregistering(struct ctl_table_header *p) -{ - /* - * if p->used is 0, nobody will ever touch that entry again; - * we'll eliminate all paths to it before dropping sysctl_lock - */ - if (unlikely(p->used)) { - struct completion wait; - init_completion(&wait); - p->unregistering = &wait; - spin_unlock(&sysctl_lock); - wait_for_completion(&wait); - spin_lock(&sysctl_lock); - } else { - /* anything non-NULL; we'll never dereference it */ - p->unregistering = ERR_PTR(-EINVAL); - } - /* - * do not remove from the list until nobody holds it; walking the - * list in do_sysctl() relies on that. - */ - erase_header(p); -} - -static void sysctl_head_get(struct ctl_table_header *head) -{ - spin_lock(&sysctl_lock); - head->count++; - spin_unlock(&sysctl_lock); -} - -void sysctl_head_put(struct ctl_table_header *head) -{ - spin_lock(&sysctl_lock); - if (!--head->count) - kfree_rcu(head, rcu); - spin_unlock(&sysctl_lock); -} - -static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) -{ - if (!head) - BUG(); - spin_lock(&sysctl_lock); - if (!use_table(head)) - head = ERR_PTR(-ENOENT); - spin_unlock(&sysctl_lock); - return head; -} - -static void sysctl_head_finish(struct ctl_table_header *head) -{ - if (!head) - return; - spin_lock(&sysctl_lock); - unuse_table(head); - spin_unlock(&sysctl_lock); -} - -static struct ctl_table_set * -lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) -{ - struct ctl_table_set *set = &root->default_set; - if (root->lookup) - set = root->lookup(root, namespaces); - return set; -} - -static struct ctl_table *lookup_entry(struct ctl_table_header **phead, - struct ctl_dir *dir, - const char *name, int namelen) -{ - struct ctl_table_header *head; - struct ctl_table *entry; - - spin_lock(&sysctl_lock); - entry = find_entry(&head, dir, name, namelen); - if (entry && use_table(head)) - *phead = head; - else - entry = NULL; - spin_unlock(&sysctl_lock); - return entry; -} - -static struct ctl_node *first_usable_entry(struct rb_node *node) -{ - struct ctl_node *ctl_node; - - for (;node; node = rb_next(node)) { - ctl_node = rb_entry(node, struct ctl_node, node); - if (use_table(ctl_node->header)) - return ctl_node; - } - return NULL; -} - -static void first_entry(struct ctl_dir *dir, - struct ctl_table_header **phead, struct ctl_table **pentry) -{ - struct ctl_table_header *head = NULL; - struct ctl_table *entry = NULL; - struct ctl_node *ctl_node; - - spin_lock(&sysctl_lock); - ctl_node = first_usable_entry(rb_first(&dir->root)); - spin_unlock(&sysctl_lock); - if (ctl_node) { - head = ctl_node->header; - entry = &head->ctl_table[ctl_node - head->node]; - } - *phead = head; - *pentry = entry; -} - -static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) -{ - struct ctl_table_header *head = *phead; - struct ctl_table *entry = *pentry; - struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; - - spin_lock(&sysctl_lock); - unuse_table(head); - - ctl_node = first_usable_entry(rb_next(&ctl_node->node)); - spin_unlock(&sysctl_lock); - head = NULL; - if (ctl_node) { - head = ctl_node->header; - entry = &head->ctl_table[ctl_node - head->node]; - } - *phead = head; - *pentry = entry; -} - -void register_sysctl_root(struct ctl_table_root *root) -{ -} - -/* - * sysctl_perm does NOT grant the superuser all rights automatically, because - * some sysctl variables are readonly even to root. - */ - -static int test_perm(int mode, int op) -{ - if (!current_euid()) - mode >>= 6; - else if (in_egroup_p(0)) - mode >>= 3; - if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) - return 0; - return -EACCES; -} - -static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op) -{ - int mode; - - if (root->permissions) - mode = root->permissions(root, current->nsproxy, table); - else - mode = table->mode; - - return test_perm(mode, op); -} - -static struct inode *proc_sys_make_inode(struct super_block *sb, - struct ctl_table_header *head, struct ctl_table *table) -{ - struct inode *inode; - struct proc_inode *ei; - - inode = new_inode(sb); - if (!inode) - goto out; - - inode->i_ino = get_next_ino(); - - sysctl_head_get(head); - ei = PROC_I(inode); - ei->sysctl = head; - ei->sysctl_entry = table; - - inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; - inode->i_mode = table->mode; - if (!S_ISDIR(table->mode)) { - inode->i_mode |= S_IFREG; - inode->i_op = &proc_sys_inode_operations; - inode->i_fop = &proc_sys_file_operations; - } else { - inode->i_mode |= S_IFDIR; - inode->i_op = &proc_sys_dir_operations; - inode->i_fop = &proc_sys_dir_file_operations; - } -out: - return inode; -} - -static struct ctl_table_header *grab_header(struct inode *inode) -{ - struct ctl_table_header *head = PROC_I(inode)->sysctl; - if (!head) - head = &sysctl_table_root.default_set.dir.header; - return sysctl_head_grab(head); -} - -static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, - struct nameidata *nd) -{ - struct ctl_table_header *head = grab_header(dir); - struct ctl_table_header *h = NULL; - struct qstr *name = &dentry->d_name; - struct ctl_table *p; - struct inode *inode; - struct dentry *err = ERR_PTR(-ENOENT); - struct ctl_dir *ctl_dir; - int ret; - - if (IS_ERR(head)) - return ERR_CAST(head); - - ctl_dir = container_of(head, struct ctl_dir, header); - - p = lookup_entry(&h, ctl_dir, name->name, name->len); - if (!p) - goto out; - - if (S_ISLNK(p->mode)) { - ret = sysctl_follow_link(&h, &p, current->nsproxy); - err = ERR_PTR(ret); - if (ret) - goto out; - } - - err = ERR_PTR(-ENOMEM); - inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); - if (h) - sysctl_head_finish(h); - - if (!inode) - goto out; - - err = NULL; - d_set_d_op(dentry, &proc_sys_dentry_operations); - d_add(dentry, inode); - -out: - sysctl_head_finish(head); - return err; -} - -static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, - size_t count, loff_t *ppos, int write) -{ - struct inode *inode = filp->f_path.dentry->d_inode; - struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; - ssize_t error; - size_t res; - - if (IS_ERR(head)) - return PTR_ERR(head); - - /* - * At this point we know that the sysctl was not unregistered - * and won't be until we finish. - */ - error = -EPERM; - if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) - goto out; - - /* if that can happen at all, it should be -EINVAL, not -EISDIR */ - error = -EINVAL; - if (!table->proc_handler) - goto out; - - /* careful: calling conventions are nasty here */ - res = count; - error = table->proc_handler(table, write, buf, &res, ppos); - if (!error) - error = res; -out: - sysctl_head_finish(head); - - return error; -} - -static ssize_t proc_sys_read(struct file *filp, char __user *buf, - size_t count, loff_t *ppos) -{ - return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); -} - -static ssize_t proc_sys_write(struct file *filp, const char __user *buf, - size_t count, loff_t *ppos) -{ - return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); -} - -static int proc_sys_open(struct inode *inode, struct file *filp) -{ - struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; - - /* sysctl was unregistered */ - if (IS_ERR(head)) - return PTR_ERR(head); - - if (table->poll) - filp->private_data = proc_sys_poll_event(table->poll); - - sysctl_head_finish(head); - - return 0; -} - -static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) -{ - struct inode *inode = filp->f_path.dentry->d_inode; - struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; - unsigned int ret = DEFAULT_POLLMASK; - unsigned long event; - - /* sysctl was unregistered */ - if (IS_ERR(head)) - return POLLERR | POLLHUP; - - if (!table->proc_handler) - goto out; - - if (!table->poll) - goto out; - - event = (unsigned long)filp->private_data; - poll_wait(filp, &table->poll->wait, wait); - - if (event != atomic_read(&table->poll->event)) { - filp->private_data = proc_sys_poll_event(table->poll); - ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; - } - -out: - sysctl_head_finish(head); - - return ret; -} - -static int proc_sys_fill_cache(struct file *filp, void *dirent, - filldir_t filldir, - struct ctl_table_header *head, - struct ctl_table *table) -{ - struct dentry *child, *dir = filp->f_path.dentry; - struct inode *inode; - struct qstr qname; - ino_t ino = 0; - unsigned type = DT_UNKNOWN; - - qname.name = table->procname; - qname.len = strlen(table->procname); - qname.hash = full_name_hash(qname.name, qname.len); - - child = d_lookup(dir, &qname); - if (!child) { - child = d_alloc(dir, &qname); - if (child) { - inode = proc_sys_make_inode(dir->d_sb, head, table); - if (!inode) { - dput(child); - return -ENOMEM; - } else { - d_set_d_op(child, &proc_sys_dentry_operations); - d_add(child, inode); - } - } else { - return -ENOMEM; - } - } - inode = child->d_inode; - ino = inode->i_ino; - type = inode->i_mode >> 12; - dput(child); - return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); -} - -static int proc_sys_link_fill_cache(struct file *filp, void *dirent, - filldir_t filldir, - struct ctl_table_header *head, - struct ctl_table *table) -{ - int err, ret = 0; - head = sysctl_head_grab(head); - - if (S_ISLNK(table->mode)) { - /* It is not an error if we can not follow the link ignore it */ - err = sysctl_follow_link(&head, &table, current->nsproxy); - if (err) - goto out; - } - - ret = proc_sys_fill_cache(filp, dirent, filldir, head, table); -out: - sysctl_head_finish(head); - return ret; -} - -static int scan(struct ctl_table_header *head, ctl_table *table, - unsigned long *pos, struct file *file, - void *dirent, filldir_t filldir) -{ - int res; - - if ((*pos)++ < file->f_pos) - return 0; - - if (unlikely(S_ISLNK(table->mode))) - res = proc_sys_link_fill_cache(file, dirent, filldir, head, table); - else - res = proc_sys_fill_cache(file, dirent, filldir, head, table); - - if (res == 0) - file->f_pos = *pos; - - return res; -} - -static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) -{ - struct dentry *dentry = filp->f_path.dentry; - struct inode *inode = dentry->d_inode; - struct ctl_table_header *head = grab_header(inode); - struct ctl_table_header *h = NULL; - struct ctl_table *entry; - struct ctl_dir *ctl_dir; - unsigned long pos; - int ret = -EINVAL; - - if (IS_ERR(head)) - return PTR_ERR(head); - - ctl_dir = container_of(head, struct ctl_dir, header); - - ret = 0; - /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ - if (filp->f_pos == 0) { - if (filldir(dirent, ".", 1, filp->f_pos, - inode->i_ino, DT_DIR) < 0) - goto out; - filp->f_pos++; - } - if (filp->f_pos == 1) { - if (filldir(dirent, "..", 2, filp->f_pos, - parent_ino(dentry), DT_DIR) < 0) - goto out; - filp->f_pos++; - } - pos = 2; - - for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { - ret = scan(h, entry, &pos, filp, dirent, filldir); - if (ret) { - sysctl_head_finish(h); - break; - } - } - ret = 1; -out: - sysctl_head_finish(head); - return ret; -} - -static int proc_sys_permission(struct inode *inode, int mask) -{ - /* - * sysctl entries that are not writeable, - * are _NOT_ writeable, capabilities or not. - */ - struct ctl_table_header *head; - struct ctl_table *table; - int error; - - /* Executable files are not allowed under /proc/sys/ */ - if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) - return -EACCES; - - head = grab_header(inode); - if (IS_ERR(head)) - return PTR_ERR(head); - - table = PROC_I(inode)->sysctl_entry; - if (!table) /* global root - r-xr-xr-x */ - error = mask & MAY_WRITE ? -EACCES : 0; - else /* Use the permissions on the sysctl table entry */ - error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK); - - sysctl_head_finish(head); - return error; -} - -static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) -{ - struct inode *inode = dentry->d_inode; - int error; - - if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) - return -EPERM; - - error = inode_change_ok(inode, attr); - if (error) - return error; - - if ((attr->ia_valid & ATTR_SIZE) && - attr->ia_size != i_size_read(inode)) { - error = vmtruncate(inode, attr->ia_size); - if (error) - return error; - } - - setattr_copy(inode, attr); - mark_inode_dirty(inode); - return 0; -} - -static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) -{ - struct inode *inode = dentry->d_inode; - struct ctl_table_header *head = grab_header(inode); - struct ctl_table *table = PROC_I(inode)->sysctl_entry; - - if (IS_ERR(head)) - return PTR_ERR(head); - - generic_fillattr(inode, stat); - if (table) - stat->mode = (stat->mode & S_IFMT) | table->mode; - - sysctl_head_finish(head); - return 0; -} - -static const struct file_operations proc_sys_file_operations = { - .open = proc_sys_open, - .poll = proc_sys_poll, - .read = proc_sys_read, - .write = proc_sys_write, - .llseek = default_llseek, -}; - -static const struct file_operations proc_sys_dir_file_operations = { - .read = generic_read_dir, - .readdir = proc_sys_readdir, - .llseek = generic_file_llseek, -}; - -static const struct inode_operations proc_sys_inode_operations = { - .permission = proc_sys_permission, - .setattr = proc_sys_setattr, - .getattr = proc_sys_getattr, -}; - -static const struct inode_operations proc_sys_dir_operations = { - .lookup = proc_sys_lookup, - .permission = proc_sys_permission, - .setattr = proc_sys_setattr, - .getattr = proc_sys_getattr, -}; - -static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) -{ - if (nd->flags & LOOKUP_RCU) - return -ECHILD; - return !PROC_I(dentry->d_inode)->sysctl->unregistering; -} - -static int proc_sys_delete(const struct dentry *dentry) -{ - return !!PROC_I(dentry->d_inode)->sysctl->unregistering; -} - -static int sysctl_is_seen(struct ctl_table_header *p) -{ - struct ctl_table_set *set = p->set; - int res; - spin_lock(&sysctl_lock); - if (p->unregistering) - res = 0; - else if (!set->is_seen) - res = 1; - else - res = set->is_seen(set); - spin_unlock(&sysctl_lock); - return res; -} - -static int proc_sys_compare(const struct dentry *parent, - const struct inode *pinode, - const struct dentry *dentry, const struct inode *inode, - unsigned int len, const char *str, const struct qstr *name) -{ - struct ctl_table_header *head; - /* Although proc doesn't have negative dentries, rcu-walk means - * that inode here can be NULL */ - /* AV: can it, indeed? */ - if (!inode) - return 1; - if (name->len != len) - return 1; - if (memcmp(name->name, str, len)) - return 1; - head = rcu_dereference(PROC_I(inode)->sysctl); - return !head || !sysctl_is_seen(head); -} - -static const struct dentry_operations proc_sys_dentry_operations = { - .d_revalidate = proc_sys_revalidate, - .d_delete = proc_sys_delete, - .d_compare = proc_sys_compare, -}; - -static struct ctl_dir *find_subdir(struct ctl_dir *dir, - const char *name, int namelen) -{ - struct ctl_table_header *head; - struct ctl_table *entry; - - entry = find_entry(&head, dir, name, namelen); - if (!entry) - return ERR_PTR(-ENOENT); - if (!S_ISDIR(entry->mode)) - return ERR_PTR(-ENOTDIR); - return container_of(head, struct ctl_dir, header); -} - -static struct ctl_dir *new_dir(struct ctl_table_set *set, - const char *name, int namelen) -{ - struct ctl_table *table; - struct ctl_dir *new; - struct ctl_node *node; - char *new_name; - - new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + - sizeof(struct ctl_table)*2 + namelen + 1, - GFP_KERNEL); - if (!new) - return NULL; - - node = (struct ctl_node *)(new + 1); - table = (struct ctl_table *)(node + 1); - new_name = (char *)(table + 2); - memcpy(new_name, name, namelen); - new_name[namelen] = '\0'; - table[0].procname = new_name; - table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; - init_header(&new->header, set->dir.header.root, set, node, table); - - return new; -} - -/** - * get_subdir - find or create a subdir with the specified name. - * @dir: Directory to create the subdirectory in - * @name: The name of the subdirectory to find or create - * @namelen: The length of name - * - * Takes a directory with an elevated reference count so we know that - * if we drop the lock the directory will not go away. Upon success - * the reference is moved from @dir to the returned subdirectory. - * Upon error an error code is returned and the reference on @dir is - * simply dropped. - */ -static struct ctl_dir *get_subdir(struct ctl_dir *dir, - const char *name, int namelen) -{ - struct ctl_table_set *set = dir->header.set; - struct ctl_dir *subdir, *new = NULL; - int err; - - spin_lock(&sysctl_lock); - subdir = find_subdir(dir, name, namelen); - if (!IS_ERR(subdir)) - goto found; - if (PTR_ERR(subdir) != -ENOENT) - goto failed; - - spin_unlock(&sysctl_lock); - new = new_dir(set, name, namelen); - spin_lock(&sysctl_lock); - subdir = ERR_PTR(-ENOMEM); - if (!new) - goto failed; - - /* Was the subdir added while we dropped the lock? */ - subdir = find_subdir(dir, name, namelen); - if (!IS_ERR(subdir)) - goto found; - if (PTR_ERR(subdir) != -ENOENT) - goto failed; - - /* Nope. Use the our freshly made directory entry. */ - err = insert_header(dir, &new->header); - subdir = ERR_PTR(err); - if (err) - goto failed; - subdir = new; -found: - subdir->header.nreg++; -failed: - if (unlikely(IS_ERR(subdir))) { - printk(KERN_ERR "sysctl could not get directory: "); - sysctl_print_dir(dir); - printk(KERN_CONT "/%*.*s %ld\n", - namelen, namelen, name, PTR_ERR(subdir)); - } - drop_sysctl_table(&dir->header); - if (new) - drop_sysctl_table(&new->header); - spin_unlock(&sysctl_lock); - return subdir; -} - -static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) -{ - struct ctl_dir *parent; - const char *procname; - if (!dir->header.parent) - return &set->dir; - parent = xlate_dir(set, dir->header.parent); - if (IS_ERR(parent)) - return parent; - procname = dir->header.ctl_table[0].procname; - return find_subdir(parent, procname, strlen(procname)); -} - -static int sysctl_follow_link(struct ctl_table_header **phead, - struct ctl_table **pentry, struct nsproxy *namespaces) -{ - struct ctl_table_header *head; - struct ctl_table_root *root; - struct ctl_table_set *set; - struct ctl_table *entry; - struct ctl_dir *dir; - int ret; - - ret = 0; - spin_lock(&sysctl_lock); - root = (*pentry)->data; - set = lookup_header_set(root, namespaces); - dir = xlate_dir(set, (*phead)->parent); - if (IS_ERR(dir)) - ret = PTR_ERR(dir); - else { - const char *procname = (*pentry)->procname; - head = NULL; - entry = find_entry(&head, dir, procname, strlen(procname)); - ret = -ENOENT; - if (entry && use_table(head)) { - unuse_table(*phead); - *phead = head; - *pentry = entry; - ret = 0; - } - } - - spin_unlock(&sysctl_lock); - return ret; -} - -static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) -{ - struct va_format vaf; - va_list args; - - va_start(args, fmt); - vaf.fmt = fmt; - vaf.va = &args; - - printk(KERN_ERR "sysctl table check failed: %s/%s %pV\n", - path, table->procname, &vaf); - - va_end(args); - return -EINVAL; -} - -static int sysctl_check_table(const char *path, struct ctl_table *table) -{ - int err = 0; - for (; table->procname; table++) { - if (table->child) - err = sysctl_err(path, table, "Not a file"); - - if ((table->proc_handler == proc_dostring) || - (table->proc_handler == proc_dointvec) || - (table->proc_handler == proc_dointvec_minmax) || - (table->proc_handler == proc_dointvec_jiffies) || - (table->proc_handler == proc_dointvec_userhz_jiffies) || - (table->proc_handler == proc_dointvec_ms_jiffies) || - (table->proc_handler == proc_doulongvec_minmax) || - (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { - if (!table->data) - err = sysctl_err(path, table, "No data"); - if (!table->maxlen) - err = sysctl_err(path, table, "No maxlen"); - } - if (!table->proc_handler) - err = sysctl_err(path, table, "No proc_handler"); - - if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) - err = sysctl_err(path, table, "bogus .mode 0%o", - table->mode); - } - return err; -} - -static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, - struct ctl_table_root *link_root) -{ - struct ctl_table *link_table, *entry, *link; - struct ctl_table_header *links; - struct ctl_node *node; - char *link_name; - int nr_entries, name_bytes; - - name_bytes = 0; - nr_entries = 0; - for (entry = table; entry->procname; entry++) { - nr_entries++; - name_bytes += strlen(entry->procname) + 1; - } - - links = kzalloc(sizeof(struct ctl_table_header) + - sizeof(struct ctl_node)*nr_entries + - sizeof(struct ctl_table)*(nr_entries + 1) + - name_bytes, - GFP_KERNEL); - - if (!links) - return NULL; - - node = (struct ctl_node *)(links + 1); - link_table = (struct ctl_table *)(node + nr_entries); - link_name = (char *)&link_table[nr_entries + 1]; - - for (link = link_table, entry = table; entry->procname; link++, entry++) { - int len = strlen(entry->procname) + 1; - memcpy(link_name, entry->procname, len); - link->procname = link_name; - link->mode = S_IFLNK|S_IRWXUGO; - link->data = link_root; - link_name += len; - } - init_header(links, dir->header.root, dir->header.set, node, link_table); - links->nreg = nr_entries; - - return links; -} - -static bool get_links(struct ctl_dir *dir, - struct ctl_table *table, struct ctl_table_root *link_root) -{ - struct ctl_table_header *head; - struct ctl_table *entry, *link; - - /* Are there links available for every entry in table? */ - for (entry = table; entry->procname; entry++) { - const char *procname = entry->procname; - link = find_entry(&head, dir, procname, strlen(procname)); - if (!link) - return false; - if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) - continue; - if (S_ISLNK(link->mode) && (link->data == link_root)) - continue; - return false; - } - - /* The checks passed. Increase the registration count on the links */ - for (entry = table; entry->procname; entry++) { - const char *procname = entry->procname; - link = find_entry(&head, dir, procname, strlen(procname)); - head->nreg++; - } - return true; -} - -static int insert_links(struct ctl_table_header *head) -{ - struct ctl_table_set *root_set = &sysctl_table_root.default_set; - struct ctl_dir *core_parent = NULL; - struct ctl_table_header *links; - int err; - - if (head->set == root_set) - return 0; - - core_parent = xlate_dir(root_set, head->parent); - if (IS_ERR(core_parent)) - return 0; - - if (get_links(core_parent, head->ctl_table, head->root)) - return 0; - - core_parent->header.nreg++; - spin_unlock(&sysctl_lock); - - links = new_links(core_parent, head->ctl_table, head->root); - - spin_lock(&sysctl_lock); - err = -ENOMEM; - if (!links) - goto out; - - err = 0; - if (get_links(core_parent, head->ctl_table, head->root)) { - kfree(links); - goto out; - } - - err = insert_header(core_parent, links); - if (err) - kfree(links); -out: - drop_sysctl_table(&core_parent->header); - return err; -} - -/** - * __register_sysctl_table - register a leaf sysctl table - * @set: Sysctl tree to register on - * @path: The path to the directory the sysctl table is in. - * @table: the top-level table structure - * - * Register a sysctl table hierarchy. @table should be a filled in ctl_table - * array. A completely 0 filled entry terminates the table. - * - * The members of the &struct ctl_table structure are used as follows: - * - * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not - * enter a sysctl file - * - * data - a pointer to data for use by proc_handler - * - * maxlen - the maximum size in bytes of the data - * - * mode - the file permissions for the /proc/sys file - * - * child - must be %NULL. - * - * proc_handler - the text handler routine (described below) - * - * extra1, extra2 - extra pointers usable by the proc handler routines - * - * Leaf nodes in the sysctl tree will be represented by a single file - * under /proc; non-leaf nodes will be represented by directories. - * - * There must be a proc_handler routine for any terminal nodes. - * Several default handlers are available to cover common cases - - * - * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), - * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), - * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() - * - * It is the handler's job to read the input buffer from user memory - * and process it. The handler should return 0 on success. - * - * This routine returns %NULL on a failure to register, and a pointer - * to the table header on success. - */ -struct ctl_table_header *__register_sysctl_table( - struct ctl_table_set *set, - const char *path, struct ctl_table *table) -{ - struct ctl_table_root *root = set->dir.header.root; - struct ctl_table_header *header; - const char *name, *nextname; - struct ctl_dir *dir; - struct ctl_table *entry; - struct ctl_node *node; - int nr_entries = 0; - - for (entry = table; entry->procname; entry++) - nr_entries++; - - header = kzalloc(sizeof(struct ctl_table_header) + - sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); - if (!header) - return NULL; - - node = (struct ctl_node *)(header + 1); - init_header(header, root, set, node, table); - if (sysctl_check_table(path, table)) - goto fail; - - spin_lock(&sysctl_lock); - dir = &set->dir; - /* Reference moved down the diretory tree get_subdir */ - dir->header.nreg++; - spin_unlock(&sysctl_lock); - - /* Find the directory for the ctl_table */ - for (name = path; name; name = nextname) { - int namelen; - nextname = strchr(name, '/'); - if (nextname) { - namelen = nextname - name; - nextname++; - } else { - namelen = strlen(name); - } - if (namelen == 0) - continue; - - dir = get_subdir(dir, name, namelen); - if (IS_ERR(dir)) - goto fail; - } - - spin_lock(&sysctl_lock); - if (insert_header(dir, header)) - goto fail_put_dir_locked; - - drop_sysctl_table(&dir->header); - spin_unlock(&sysctl_lock); - - return header; - -fail_put_dir_locked: - drop_sysctl_table(&dir->header); - spin_unlock(&sysctl_lock); -fail: - kfree(header); - dump_stack(); - return NULL; -} - -/** - * register_sysctl - register a sysctl table - * @path: The path to the directory the sysctl table is in. - * @table: the table structure - * - * Register a sysctl table. @table should be a filled in ctl_table - * array. A completely 0 filled entry terminates the table. - * - * See __register_sysctl_table for more details. - */ -struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) -{ - return __register_sysctl_table(&sysctl_table_root.default_set, - path, table); -} -EXPORT_SYMBOL(register_sysctl); - -static char *append_path(const char *path, char *pos, const char *name) -{ - int namelen; - namelen = strlen(name); - if (((pos - path) + namelen + 2) >= PATH_MAX) - return NULL; - memcpy(pos, name, namelen); - pos[namelen] = '/'; - pos[namelen + 1] = '\0'; - pos += namelen + 1; - return pos; -} - -static int count_subheaders(struct ctl_table *table) -{ - int has_files = 0; - int nr_subheaders = 0; - struct ctl_table *entry; - - /* special case: no directory and empty directory */ - if (!table || !table->procname) - return 1; - - for (entry = table; entry->procname; entry++) { - if (entry->child) - nr_subheaders += count_subheaders(entry->child); - else - has_files = 1; - } - return nr_subheaders + has_files; -} - -static int register_leaf_sysctl_tables(const char *path, char *pos, - struct ctl_table_header ***subheader, struct ctl_table_set *set, - struct ctl_table *table) -{ - struct ctl_table *ctl_table_arg = NULL; - struct ctl_table *entry, *files; - int nr_files = 0; - int nr_dirs = 0; - int err = -ENOMEM; - - for (entry = table; entry->procname; entry++) { - if (entry->child) - nr_dirs++; - else - nr_files++; - } - - files = table; - /* If there are mixed files and directories we need a new table */ - if (nr_dirs && nr_files) { - struct ctl_table *new; - files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), - GFP_KERNEL); - if (!files) - goto out; - - ctl_table_arg = files; - for (new = files, entry = table; entry->procname; entry++) { - if (entry->child) - continue; - *new = *entry; - new++; - } - } - - /* Register everything except a directory full of subdirectories */ - if (nr_files || !nr_dirs) { - struct ctl_table_header *header; - header = __register_sysctl_table(set, path, files); - if (!header) { - kfree(ctl_table_arg); - goto out; - } - - /* Remember if we need to free the file table */ - header->ctl_table_arg = ctl_table_arg; - **subheader = header; - (*subheader)++; - } - - /* Recurse into the subdirectories. */ - for (entry = table; entry->procname; entry++) { - char *child_pos; - - if (!entry->child) - continue; - - err = -ENAMETOOLONG; - child_pos = append_path(path, pos, entry->procname); - if (!child_pos) - goto out; - - err = register_leaf_sysctl_tables(path, child_pos, subheader, - set, entry->child); - pos[0] = '\0'; - if (err) - goto out; - } - err = 0; -out: - /* On failure our caller will unregister all registered subheaders */ - return err; -} - -/** - * __register_sysctl_paths - register a sysctl table hierarchy - * @set: Sysctl tree to register on - * @path: The path to the directory the sysctl table is in. - * @table: the top-level table structure - * - * Register a sysctl table hierarchy. @table should be a filled in ctl_table - * array. A completely 0 filled entry terminates the table. - * - * See __register_sysctl_table for more details. - */ -struct ctl_table_header *__register_sysctl_paths( - struct ctl_table_set *set, - const struct ctl_path *path, struct ctl_table *table) -{ - struct ctl_table *ctl_table_arg = table; - int nr_subheaders = count_subheaders(table); - struct ctl_table_header *header = NULL, **subheaders, **subheader; - const struct ctl_path *component; - char *new_path, *pos; - - pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); - if (!new_path) - return NULL; - - pos[0] = '\0'; - for (component = path; component->procname; component++) { - pos = append_path(new_path, pos, component->procname); - if (!pos) - goto out; - } - while (table->procname && table->child && !table[1].procname) { - pos = append_path(new_path, pos, table->procname); - if (!pos) - goto out; - table = table->child; - } - if (nr_subheaders == 1) { - header = __register_sysctl_table(set, new_path, table); - if (header) - header->ctl_table_arg = ctl_table_arg; - } else { - header = kzalloc(sizeof(*header) + - sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); - if (!header) - goto out; - - subheaders = (struct ctl_table_header **) (header + 1); - subheader = subheaders; - header->ctl_table_arg = ctl_table_arg; - - if (register_leaf_sysctl_tables(new_path, pos, &subheader, - set, table)) - goto err_register_leaves; - } - -out: - kfree(new_path); - return header; - -err_register_leaves: - while (subheader > subheaders) { - struct ctl_table_header *subh = *(--subheader); - struct ctl_table *table = subh->ctl_table_arg; - unregister_sysctl_table(subh); - kfree(table); - } - kfree(header); - header = NULL; - goto out; -} - -/** - * register_sysctl_table_path - register a sysctl table hierarchy - * @path: The path to the directory the sysctl table is in. - * @table: the top-level table structure - * - * Register a sysctl table hierarchy. @table should be a filled in ctl_table - * array. A completely 0 filled entry terminates the table. - * - * See __register_sysctl_paths for more details. - */ -struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, - struct ctl_table *table) -{ - return __register_sysctl_paths(&sysctl_table_root.default_set, - path, table); -} -EXPORT_SYMBOL(register_sysctl_paths); - -/** - * register_sysctl_table - register a sysctl table hierarchy - * @table: the top-level table structure - * - * Register a sysctl table hierarchy. @table should be a filled in ctl_table - * array. A completely 0 filled entry terminates the table. - * - * See register_sysctl_paths for more details. - */ -struct ctl_table_header *register_sysctl_table(struct ctl_table *table) -{ - static const struct ctl_path null_path[] = { {} }; - - return register_sysctl_paths(null_path, table); -} -EXPORT_SYMBOL(register_sysctl_table); - -static void put_links(struct ctl_table_header *header) -{ - struct ctl_table_set *root_set = &sysctl_table_root.default_set; - struct ctl_table_root *root = header->root; - struct ctl_dir *parent = header->parent; - struct ctl_dir *core_parent; - struct ctl_table *entry; - - if (header->set == root_set) - return; - - core_parent = xlate_dir(root_set, parent); - if (IS_ERR(core_parent)) - return; - - for (entry = header->ctl_table; entry->procname; entry++) { - struct ctl_table_header *link_head; - struct ctl_table *link; - const char *name = entry->procname; - - link = find_entry(&link_head, core_parent, name, strlen(name)); - if (link && - ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || - (S_ISLNK(link->mode) && (link->data == root)))) { - drop_sysctl_table(link_head); - } - else { - printk(KERN_ERR "sysctl link missing during unregister: "); - sysctl_print_dir(parent); - printk(KERN_CONT "/%s\n", name); - } - } -} - -static void drop_sysctl_table(struct ctl_table_header *header) -{ - struct ctl_dir *parent = header->parent; - - if (--header->nreg) - return; - - put_links(header); - start_unregistering(header); - if (!--header->count) - kfree_rcu(header, rcu); - - if (parent) - drop_sysctl_table(&parent->header); -} - -/** - * unregister_sysctl_table - unregister a sysctl table hierarchy - * @header: the header returned from register_sysctl_table - * - * Unregisters the sysctl table and all children. proc entries may not - * actually be removed until they are no longer used by anyone. - */ -void unregister_sysctl_table(struct ctl_table_header * header) -{ - int nr_subheaders; - might_sleep(); - - if (header == NULL) - return; - - nr_subheaders = count_subheaders(header->ctl_table_arg); - if (unlikely(nr_subheaders > 1)) { - struct ctl_table_header **subheaders; - int i; - - subheaders = (struct ctl_table_header **)(header + 1); - for (i = nr_subheaders -1; i >= 0; i--) { - struct ctl_table_header *subh = subheaders[i]; - struct ctl_table *table = subh->ctl_table_arg; - unregister_sysctl_table(subh); - kfree(table); - } - kfree(header); - return; - } - - spin_lock(&sysctl_lock); - drop_sysctl_table(header); - spin_unlock(&sysctl_lock); -} -EXPORT_SYMBOL(unregister_sysctl_table); - -void setup_sysctl_set(struct ctl_table_set *set, - struct ctl_table_root *root, - int (*is_seen)(struct ctl_table_set *)) -{ - memset(set, 0, sizeof(*set)); - set->is_seen = is_seen; - init_header(&set->dir.header, root, set, NULL, root_table); -} - -void retire_sysctl_set(struct ctl_table_set *set) -{ - WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); -} - -int __init proc_sys_init(void) -{ - struct proc_dir_entry *proc_sys_root; - - proc_sys_root = proc_mkdir("sys", NULL); - proc_sys_root->proc_iops = &proc_sys_dir_operations; - proc_sys_root->proc_fops = &proc_sys_dir_file_operations; - proc_sys_root->nlink = 0; - - return sysctl_init(); -} |