mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1863 lines
46 KiB
1863 lines
46 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* /proc/sys support |
|
*/ |
|
#include <linux/init.h> |
|
#include <linux/sysctl.h> |
|
#include <linux/poll.h> |
|
#include <linux/proc_fs.h> |
|
#include <linux/printk.h> |
|
#include <linux/security.h> |
|
#include <linux/sched.h> |
|
#include <linux/cred.h> |
|
#include <linux/namei.h> |
|
#include <linux/mm.h> |
|
#include <linux/uio.h> |
|
#include <linux/module.h> |
|
#include <linux/bpf-cgroup.h> |
|
#include <linux/mount.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; |
|
|
|
/* shared constants to be used in various sysctls */ |
|
const int sysctl_vals[] = { 0, 1, INT_MAX }; |
|
EXPORT_SYMBOL(sysctl_vals); |
|
|
|
/* Support for permanently empty directories */ |
|
|
|
struct ctl_table sysctl_mount_point[] = { |
|
{ } |
|
}; |
|
|
|
static bool is_empty_dir(struct ctl_table_header *head) |
|
{ |
|
return head->ctl_table[0].child == sysctl_mount_point; |
|
} |
|
|
|
static void set_empty_dir(struct ctl_dir *dir) |
|
{ |
|
dir->header.ctl_table[0].child = sysctl_mount_point; |
|
} |
|
|
|
static void clear_empty_dir(struct ctl_dir *dir) |
|
|
|
{ |
|
dir->header.ctl_table[0].child = NULL; |
|
} |
|
|
|
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); |
|
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); |
|
pr_cont("%s/", dir->header.ctl_table[0].procname); |
|
} |
|
|
|
static int namecmp(const char *name1, int len1, const char *name2, int len2) |
|
{ |
|
int cmp; |
|
|
|
cmp = memcmp(name1, name2, min(len1, len2)); |
|
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 { |
|
pr_err("sysctl duplicate entry: "); |
|
sysctl_print_dir(head->parent); |
|
pr_cont("/%s\n", entry->procname); |
|
return -EEXIST; |
|
} |
|
} |
|
|
|
rb_link_node(node, parent, p); |
|
rb_insert_color(node, &head->parent->root); |
|
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; |
|
INIT_HLIST_HEAD(&head->inodes); |
|
if (node) { |
|
struct ctl_table *entry; |
|
for (entry = table; entry->procname; entry++, 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; |
|
|
|
/* Is this a permanently empty directory? */ |
|
if (is_empty_dir(&dir->header)) |
|
return -EROFS; |
|
|
|
/* Am I creating a permanently empty directory? */ |
|
if (header->ctl_table == sysctl_mount_point) { |
|
if (!RB_EMPTY_ROOT(&dir->root)) |
|
return -EINVAL; |
|
set_empty_dir(dir); |
|
} |
|
|
|
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: |
|
if (header->ctl_table == sysctl_mount_point) |
|
clear_empty_dir(dir); |
|
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); |
|
} |
|
|
|
static void proc_sys_invalidate_dcache(struct ctl_table_header *head) |
|
{ |
|
proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); |
|
} |
|
|
|
/* 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); |
|
} else { |
|
/* anything non-NULL; we'll never dereference it */ |
|
p->unregistering = ERR_PTR(-EINVAL); |
|
spin_unlock(&sysctl_lock); |
|
} |
|
/* |
|
* Invalidate dentries for unregistered sysctls: namespaced sysctls |
|
* can have duplicate names and contaminate dcache very badly. |
|
*/ |
|
proc_sys_invalidate_dcache(p); |
|
/* |
|
* do not remove from the list until nobody holds it; walking the |
|
* list in do_sysctl() relies on that. |
|
*/ |
|
spin_lock(&sysctl_lock); |
|
erase_header(p); |
|
} |
|
|
|
static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) |
|
{ |
|
BUG_ON(!head); |
|
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 ctl_table_set *set = &root->default_set; |
|
if (root->lookup) |
|
set = root->lookup(root); |
|
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; |
|
} |
|
|
|
/* |
|
* 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 (uid_eq(current_euid(), GLOBAL_ROOT_UID)) |
|
mode >>= 6; |
|
else if (in_egroup_p(GLOBAL_ROOT_GID)) |
|
mode >>= 3; |
|
if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) |
|
return 0; |
|
return -EACCES; |
|
} |
|
|
|
static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) |
|
{ |
|
struct ctl_table_root *root = head->root; |
|
int mode; |
|
|
|
if (root->permissions) |
|
mode = root->permissions(head, 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 ctl_table_root *root = head->root; |
|
struct inode *inode; |
|
struct proc_inode *ei; |
|
|
|
inode = new_inode(sb); |
|
if (!inode) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
inode->i_ino = get_next_ino(); |
|
|
|
ei = PROC_I(inode); |
|
|
|
spin_lock(&sysctl_lock); |
|
if (unlikely(head->unregistering)) { |
|
spin_unlock(&sysctl_lock); |
|
iput(inode); |
|
return ERR_PTR(-ENOENT); |
|
} |
|
ei->sysctl = head; |
|
ei->sysctl_entry = table; |
|
hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); |
|
head->count++; |
|
spin_unlock(&sysctl_lock); |
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
|
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; |
|
if (is_empty_dir(head)) |
|
make_empty_dir_inode(inode); |
|
} |
|
|
|
if (root->set_ownership) |
|
root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); |
|
else { |
|
inode->i_uid = GLOBAL_ROOT_UID; |
|
inode->i_gid = GLOBAL_ROOT_GID; |
|
} |
|
|
|
return inode; |
|
} |
|
|
|
void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) |
|
{ |
|
spin_lock(&sysctl_lock); |
|
hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); |
|
if (!--head->count) |
|
kfree_rcu(head, rcu); |
|
spin_unlock(&sysctl_lock); |
|
} |
|
|
|
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, |
|
unsigned int flags) |
|
{ |
|
struct ctl_table_header *head = grab_header(dir); |
|
struct ctl_table_header *h = NULL; |
|
const 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); |
|
err = ERR_PTR(ret); |
|
if (ret) |
|
goto out; |
|
} |
|
|
|
inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); |
|
if (IS_ERR(inode)) { |
|
err = ERR_CAST(inode); |
|
goto out; |
|
} |
|
|
|
d_set_d_op(dentry, &proc_sys_dentry_operations); |
|
err = d_splice_alias(inode, dentry); |
|
|
|
out: |
|
if (h) |
|
sysctl_head_finish(h); |
|
sysctl_head_finish(head); |
|
return err; |
|
} |
|
|
|
static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, |
|
int write) |
|
{ |
|
struct inode *inode = file_inode(iocb->ki_filp); |
|
struct ctl_table_header *head = grab_header(inode); |
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
|
size_t count = iov_iter_count(iter); |
|
char *kbuf; |
|
ssize_t error; |
|
|
|
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, 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; |
|
|
|
/* don't even try if the size is too large */ |
|
error = -ENOMEM; |
|
if (count >= KMALLOC_MAX_SIZE) |
|
goto out; |
|
kbuf = kvzalloc(count + 1, GFP_KERNEL); |
|
if (!kbuf) |
|
goto out; |
|
|
|
if (write) { |
|
error = -EFAULT; |
|
if (!copy_from_iter_full(kbuf, count, iter)) |
|
goto out_free_buf; |
|
kbuf[count] = '\0'; |
|
} |
|
|
|
error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, |
|
&iocb->ki_pos); |
|
if (error) |
|
goto out_free_buf; |
|
|
|
/* careful: calling conventions are nasty here */ |
|
error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); |
|
if (error) |
|
goto out_free_buf; |
|
|
|
if (!write) { |
|
error = -EFAULT; |
|
if (copy_to_iter(kbuf, count, iter) < count) |
|
goto out_free_buf; |
|
} |
|
|
|
error = count; |
|
out_free_buf: |
|
kvfree(kbuf); |
|
out: |
|
sysctl_head_finish(head); |
|
|
|
return error; |
|
} |
|
|
|
static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) |
|
{ |
|
return proc_sys_call_handler(iocb, iter, 0); |
|
} |
|
|
|
static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) |
|
{ |
|
return proc_sys_call_handler(iocb, iter, 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 __poll_t proc_sys_poll(struct file *filp, poll_table *wait) |
|
{ |
|
struct inode *inode = file_inode(filp); |
|
struct ctl_table_header *head = grab_header(inode); |
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
|
__poll_t ret = DEFAULT_POLLMASK; |
|
unsigned long event; |
|
|
|
/* sysctl was unregistered */ |
|
if (IS_ERR(head)) |
|
return EPOLLERR | EPOLLHUP; |
|
|
|
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 = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; |
|
} |
|
|
|
out: |
|
sysctl_head_finish(head); |
|
|
|
return ret; |
|
} |
|
|
|
static bool proc_sys_fill_cache(struct file *file, |
|
struct dir_context *ctx, |
|
struct ctl_table_header *head, |
|
struct ctl_table *table) |
|
{ |
|
struct dentry *child, *dir = file->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(dir, qname.name, qname.len); |
|
|
|
child = d_lookup(dir, &qname); |
|
if (!child) { |
|
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); |
|
child = d_alloc_parallel(dir, &qname, &wq); |
|
if (IS_ERR(child)) |
|
return false; |
|
if (d_in_lookup(child)) { |
|
struct dentry *res; |
|
inode = proc_sys_make_inode(dir->d_sb, head, table); |
|
if (IS_ERR(inode)) { |
|
d_lookup_done(child); |
|
dput(child); |
|
return false; |
|
} |
|
d_set_d_op(child, &proc_sys_dentry_operations); |
|
res = d_splice_alias(inode, child); |
|
d_lookup_done(child); |
|
if (unlikely(res)) { |
|
if (IS_ERR(res)) { |
|
dput(child); |
|
return false; |
|
} |
|
dput(child); |
|
child = res; |
|
} |
|
} |
|
} |
|
inode = d_inode(child); |
|
ino = inode->i_ino; |
|
type = inode->i_mode >> 12; |
|
dput(child); |
|
return dir_emit(ctx, qname.name, qname.len, ino, type); |
|
} |
|
|
|
static bool proc_sys_link_fill_cache(struct file *file, |
|
struct dir_context *ctx, |
|
struct ctl_table_header *head, |
|
struct ctl_table *table) |
|
{ |
|
bool ret = true; |
|
|
|
head = sysctl_head_grab(head); |
|
if (IS_ERR(head)) |
|
return false; |
|
|
|
/* It is not an error if we can not follow the link ignore it */ |
|
if (sysctl_follow_link(&head, &table)) |
|
goto out; |
|
|
|
ret = proc_sys_fill_cache(file, ctx, head, table); |
|
out: |
|
sysctl_head_finish(head); |
|
return ret; |
|
} |
|
|
|
static int scan(struct ctl_table_header *head, struct ctl_table *table, |
|
unsigned long *pos, struct file *file, |
|
struct dir_context *ctx) |
|
{ |
|
bool res; |
|
|
|
if ((*pos)++ < ctx->pos) |
|
return true; |
|
|
|
if (unlikely(S_ISLNK(table->mode))) |
|
res = proc_sys_link_fill_cache(file, ctx, head, table); |
|
else |
|
res = proc_sys_fill_cache(file, ctx, head, table); |
|
|
|
if (res) |
|
ctx->pos = *pos; |
|
|
|
return res; |
|
} |
|
|
|
static int proc_sys_readdir(struct file *file, struct dir_context *ctx) |
|
{ |
|
struct ctl_table_header *head = grab_header(file_inode(file)); |
|
struct ctl_table_header *h = NULL; |
|
struct ctl_table *entry; |
|
struct ctl_dir *ctl_dir; |
|
unsigned long pos; |
|
|
|
if (IS_ERR(head)) |
|
return PTR_ERR(head); |
|
|
|
ctl_dir = container_of(head, struct ctl_dir, header); |
|
|
|
if (!dir_emit_dots(file, ctx)) |
|
goto out; |
|
|
|
pos = 2; |
|
|
|
for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { |
|
if (!scan(h, entry, &pos, file, ctx)) { |
|
sysctl_head_finish(h); |
|
break; |
|
} |
|
} |
|
out: |
|
sysctl_head_finish(head); |
|
return 0; |
|
} |
|
|
|
static int proc_sys_permission(struct user_namespace *mnt_userns, |
|
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, table, mask & ~MAY_NOT_BLOCK); |
|
|
|
sysctl_head_finish(head); |
|
return error; |
|
} |
|
|
|
static int proc_sys_setattr(struct user_namespace *mnt_userns, |
|
struct dentry *dentry, struct iattr *attr) |
|
{ |
|
struct inode *inode = d_inode(dentry); |
|
int error; |
|
|
|
if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) |
|
return -EPERM; |
|
|
|
error = setattr_prepare(&init_user_ns, dentry, attr); |
|
if (error) |
|
return error; |
|
|
|
setattr_copy(&init_user_ns, inode, attr); |
|
mark_inode_dirty(inode); |
|
return 0; |
|
} |
|
|
|
static int proc_sys_getattr(struct user_namespace *mnt_userns, |
|
const struct path *path, struct kstat *stat, |
|
u32 request_mask, unsigned int query_flags) |
|
{ |
|
struct inode *inode = d_inode(path->dentry); |
|
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(&init_user_ns, 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_iter = proc_sys_read, |
|
.write_iter = proc_sys_write, |
|
.splice_read = generic_file_splice_read, |
|
.splice_write = iter_file_splice_write, |
|
.llseek = default_llseek, |
|
}; |
|
|
|
static const struct file_operations proc_sys_dir_file_operations = { |
|
.read = generic_read_dir, |
|
.iterate_shared = 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, unsigned int flags) |
|
{ |
|
if (flags & LOOKUP_RCU) |
|
return -ECHILD; |
|
return !PROC_I(d_inode(dentry))->sysctl->unregistering; |
|
} |
|
|
|
static int proc_sys_delete(const struct dentry *dentry) |
|
{ |
|
return !!PROC_I(d_inode(dentry))->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 *dentry, |
|
unsigned int len, const char *str, const struct qstr *name) |
|
{ |
|
struct ctl_table_header *head; |
|
struct inode *inode; |
|
|
|
/* Although proc doesn't have negative dentries, rcu-walk means |
|
* that inode here can be NULL */ |
|
/* AV: can it, indeed? */ |
|
inode = d_inode_rcu(dentry); |
|
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 (IS_ERR(subdir)) { |
|
pr_err("sysctl could not get directory: "); |
|
sysctl_print_dir(dir); |
|
pr_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 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); |
|
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; |
|
|
|
pr_err("sysctl table check failed: %s/%s %pV\n", |
|
path, table->procname, &vaf); |
|
|
|
va_end(args); |
|
return -EINVAL; |
|
} |
|
|
|
static int sysctl_check_table_array(const char *path, struct ctl_table *table) |
|
{ |
|
int err = 0; |
|
|
|
if ((table->proc_handler == proc_douintvec) || |
|
(table->proc_handler == proc_douintvec_minmax)) { |
|
if (table->maxlen != sizeof(unsigned int)) |
|
err |= sysctl_err(path, table, "array not allowed"); |
|
} |
|
|
|
if (table->proc_handler == proc_dou8vec_minmax) { |
|
if (table->maxlen != sizeof(u8)) |
|
err |= sysctl_err(path, table, "array not allowed"); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
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_douintvec) || |
|
(table->proc_handler == proc_douintvec_minmax) || |
|
(table->proc_handler == proc_dointvec_minmax) || |
|
(table->proc_handler == proc_dou8vec_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"); |
|
else |
|
err |= sysctl_check_table_array(path, table); |
|
} |
|
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 = kcalloc(nr_files + 1, sizeof(struct ctl_table), |
|
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_paths - 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 { |
|
pr_err("sysctl link missing during unregister: "); |
|
sysctl_print_dir(parent); |
|
pr_cont("/%s\n", name); |
|
} |
|
} |
|
} |
|
|
|
static void drop_sysctl_table(struct ctl_table_header *header) |
|
{ |
|
struct ctl_dir *parent = header->parent; |
|
|
|
if (--header->nreg) |
|
return; |
|
|
|
if (parent) { |
|
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_dir_ops = &proc_sys_dir_file_operations; |
|
proc_sys_root->nlink = 0; |
|
|
|
return sysctl_init(); |
|
} |
|
|
|
struct sysctl_alias { |
|
const char *kernel_param; |
|
const char *sysctl_param; |
|
}; |
|
|
|
/* |
|
* Historically some settings had both sysctl and a command line parameter. |
|
* With the generic sysctl. parameter support, we can handle them at a single |
|
* place and only keep the historical name for compatibility. This is not meant |
|
* to add brand new aliases. When adding existing aliases, consider whether |
|
* the possibly different moment of changing the value (e.g. from early_param |
|
* to the moment do_sysctl_args() is called) is an issue for the specific |
|
* parameter. |
|
*/ |
|
static const struct sysctl_alias sysctl_aliases[] = { |
|
{"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, |
|
{"hung_task_panic", "kernel.hung_task_panic" }, |
|
{"numa_zonelist_order", "vm.numa_zonelist_order" }, |
|
{"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, |
|
{"softlockup_panic", "kernel.softlockup_panic" }, |
|
{ } |
|
}; |
|
|
|
static const char *sysctl_find_alias(char *param) |
|
{ |
|
const struct sysctl_alias *alias; |
|
|
|
for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { |
|
if (strcmp(alias->kernel_param, param) == 0) |
|
return alias->sysctl_param; |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
/* Set sysctl value passed on kernel command line. */ |
|
static int process_sysctl_arg(char *param, char *val, |
|
const char *unused, void *arg) |
|
{ |
|
char *path; |
|
struct vfsmount **proc_mnt = arg; |
|
struct file_system_type *proc_fs_type; |
|
struct file *file; |
|
int len; |
|
int err; |
|
loff_t pos = 0; |
|
ssize_t wret; |
|
|
|
if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { |
|
param += sizeof("sysctl") - 1; |
|
|
|
if (param[0] != '/' && param[0] != '.') |
|
return 0; |
|
|
|
param++; |
|
} else { |
|
param = (char *) sysctl_find_alias(param); |
|
if (!param) |
|
return 0; |
|
} |
|
|
|
if (!val) |
|
return -EINVAL; |
|
len = strlen(val); |
|
if (len == 0) |
|
return -EINVAL; |
|
|
|
/* |
|
* To set sysctl options, we use a temporary mount of proc, look up the |
|
* respective sys/ file and write to it. To avoid mounting it when no |
|
* options were given, we mount it only when the first sysctl option is |
|
* found. Why not a persistent mount? There are problems with a |
|
* persistent mount of proc in that it forces userspace not to use any |
|
* proc mount options. |
|
*/ |
|
if (!*proc_mnt) { |
|
proc_fs_type = get_fs_type("proc"); |
|
if (!proc_fs_type) { |
|
pr_err("Failed to find procfs to set sysctl from command line\n"); |
|
return 0; |
|
} |
|
*proc_mnt = kern_mount(proc_fs_type); |
|
put_filesystem(proc_fs_type); |
|
if (IS_ERR(*proc_mnt)) { |
|
pr_err("Failed to mount procfs to set sysctl from command line\n"); |
|
return 0; |
|
} |
|
} |
|
|
|
path = kasprintf(GFP_KERNEL, "sys/%s", param); |
|
if (!path) |
|
panic("%s: Failed to allocate path for %s\n", __func__, param); |
|
strreplace(path, '.', '/'); |
|
|
|
file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); |
|
if (IS_ERR(file)) { |
|
err = PTR_ERR(file); |
|
if (err == -ENOENT) |
|
pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", |
|
param, val); |
|
else if (err == -EACCES) |
|
pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", |
|
param, val); |
|
else |
|
pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", |
|
file, param, val); |
|
goto out; |
|
} |
|
wret = kernel_write(file, val, len, &pos); |
|
if (wret < 0) { |
|
err = wret; |
|
if (err == -EINVAL) |
|
pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", |
|
param, val); |
|
else |
|
pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", |
|
ERR_PTR(err), param, val); |
|
} else if (wret != len) { |
|
pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", |
|
wret, len, path, param, val); |
|
} |
|
|
|
err = filp_close(file, NULL); |
|
if (err) |
|
pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", |
|
ERR_PTR(err), param, val); |
|
out: |
|
kfree(path); |
|
return 0; |
|
} |
|
|
|
void do_sysctl_args(void) |
|
{ |
|
char *command_line; |
|
struct vfsmount *proc_mnt = NULL; |
|
|
|
command_line = kstrdup(saved_command_line, GFP_KERNEL); |
|
if (!command_line) |
|
panic("%s: Failed to allocate copy of command line\n", __func__); |
|
|
|
parse_args("Setting sysctl args", command_line, |
|
NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); |
|
|
|
if (proc_mnt) |
|
kern_unmount(proc_mnt); |
|
|
|
kfree(command_line); |
|
}
|
|
|