ktest: Check parent options for iterated tests
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / proc / proc_sysctl.c
bloba6b62173d4c310e4fa4b131a214043667fa67726
1 /*
2 * /proc/sys support
3 */
4 #include <linux/init.h>
5 #include <linux/sysctl.h>
6 #include <linux/poll.h>
7 #include <linux/proc_fs.h>
8 #include <linux/security.h>
9 #include <linux/namei.h>
10 #include "internal.h"
12 static const struct dentry_operations proc_sys_dentry_operations;
13 static const struct file_operations proc_sys_file_operations;
14 static const struct inode_operations proc_sys_inode_operations;
15 static const struct file_operations proc_sys_dir_file_operations;
16 static const struct inode_operations proc_sys_dir_operations;
18 void proc_sys_poll_notify(struct ctl_table_poll *poll)
20 if (!poll)
21 return;
23 atomic_inc(&poll->event);
24 wake_up_interruptible(&poll->wait);
27 static struct inode *proc_sys_make_inode(struct super_block *sb,
28 struct ctl_table_header *head, struct ctl_table *table)
30 struct inode *inode;
31 struct proc_inode *ei;
33 inode = new_inode(sb);
34 if (!inode)
35 goto out;
37 inode->i_ino = get_next_ino();
39 sysctl_head_get(head);
40 ei = PROC_I(inode);
41 ei->sysctl = head;
42 ei->sysctl_entry = table;
44 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
45 inode->i_mode = table->mode;
46 if (!table->child) {
47 inode->i_mode |= S_IFREG;
48 inode->i_op = &proc_sys_inode_operations;
49 inode->i_fop = &proc_sys_file_operations;
50 } else {
51 inode->i_mode |= S_IFDIR;
52 clear_nlink(inode);
53 inode->i_op = &proc_sys_dir_operations;
54 inode->i_fop = &proc_sys_dir_file_operations;
56 out:
57 return inode;
60 static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
62 int len;
63 for ( ; p->procname; p++) {
65 if (!p->procname)
66 continue;
68 len = strlen(p->procname);
69 if (len != name->len)
70 continue;
72 if (memcmp(p->procname, name->name, len) != 0)
73 continue;
75 /* I have a match */
76 return p;
78 return NULL;
81 static struct ctl_table_header *grab_header(struct inode *inode)
83 if (PROC_I(inode)->sysctl)
84 return sysctl_head_grab(PROC_I(inode)->sysctl);
85 else
86 return sysctl_head_next(NULL);
89 static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
90 struct nameidata *nd)
92 struct ctl_table_header *head = grab_header(dir);
93 struct ctl_table *table = PROC_I(dir)->sysctl_entry;
94 struct ctl_table_header *h = NULL;
95 struct qstr *name = &dentry->d_name;
96 struct ctl_table *p;
97 struct inode *inode;
98 struct dentry *err = ERR_PTR(-ENOENT);
100 if (IS_ERR(head))
101 return ERR_CAST(head);
103 if (table && !table->child) {
104 WARN_ON(1);
105 goto out;
108 table = table ? table->child : head->ctl_table;
110 p = find_in_table(table, name);
111 if (!p) {
112 for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
113 if (h->attached_to != table)
114 continue;
115 p = find_in_table(h->attached_by, name);
116 if (p)
117 break;
121 if (!p)
122 goto out;
124 err = ERR_PTR(-ENOMEM);
125 inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
126 if (h)
127 sysctl_head_finish(h);
129 if (!inode)
130 goto out;
132 err = NULL;
133 d_set_d_op(dentry, &proc_sys_dentry_operations);
134 d_add(dentry, inode);
136 out:
137 sysctl_head_finish(head);
138 return err;
141 static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
142 size_t count, loff_t *ppos, int write)
144 struct inode *inode = filp->f_path.dentry->d_inode;
145 struct ctl_table_header *head = grab_header(inode);
146 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
147 ssize_t error;
148 size_t res;
150 if (IS_ERR(head))
151 return PTR_ERR(head);
154 * At this point we know that the sysctl was not unregistered
155 * and won't be until we finish.
157 error = -EPERM;
158 if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
159 goto out;
161 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
162 error = -EINVAL;
163 if (!table->proc_handler)
164 goto out;
166 /* careful: calling conventions are nasty here */
167 res = count;
168 error = table->proc_handler(table, write, buf, &res, ppos);
169 if (!error)
170 error = res;
171 out:
172 sysctl_head_finish(head);
174 return error;
177 static ssize_t proc_sys_read(struct file *filp, char __user *buf,
178 size_t count, loff_t *ppos)
180 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
183 static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
184 size_t count, loff_t *ppos)
186 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
189 static int proc_sys_open(struct inode *inode, struct file *filp)
191 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
193 if (table->poll)
194 filp->private_data = proc_sys_poll_event(table->poll);
196 return 0;
199 static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
201 struct inode *inode = filp->f_path.dentry->d_inode;
202 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
203 unsigned long event = (unsigned long)filp->private_data;
204 unsigned int ret = DEFAULT_POLLMASK;
206 if (!table->proc_handler)
207 goto out;
209 if (!table->poll)
210 goto out;
212 poll_wait(filp, &table->poll->wait, wait);
214 if (event != atomic_read(&table->poll->event)) {
215 filp->private_data = proc_sys_poll_event(table->poll);
216 ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI;
219 out:
220 return ret;
223 static int proc_sys_fill_cache(struct file *filp, void *dirent,
224 filldir_t filldir,
225 struct ctl_table_header *head,
226 struct ctl_table *table)
228 struct dentry *child, *dir = filp->f_path.dentry;
229 struct inode *inode;
230 struct qstr qname;
231 ino_t ino = 0;
232 unsigned type = DT_UNKNOWN;
234 qname.name = table->procname;
235 qname.len = strlen(table->procname);
236 qname.hash = full_name_hash(qname.name, qname.len);
238 child = d_lookup(dir, &qname);
239 if (!child) {
240 child = d_alloc(dir, &qname);
241 if (child) {
242 inode = proc_sys_make_inode(dir->d_sb, head, table);
243 if (!inode) {
244 dput(child);
245 return -ENOMEM;
246 } else {
247 d_set_d_op(child, &proc_sys_dentry_operations);
248 d_add(child, inode);
250 } else {
251 return -ENOMEM;
254 inode = child->d_inode;
255 ino = inode->i_ino;
256 type = inode->i_mode >> 12;
257 dput(child);
258 return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
261 static int scan(struct ctl_table_header *head, ctl_table *table,
262 unsigned long *pos, struct file *file,
263 void *dirent, filldir_t filldir)
266 for (; table->procname; table++, (*pos)++) {
267 int res;
269 /* Can't do anything without a proc name */
270 if (!table->procname)
271 continue;
273 if (*pos < file->f_pos)
274 continue;
276 res = proc_sys_fill_cache(file, dirent, filldir, head, table);
277 if (res)
278 return res;
280 file->f_pos = *pos + 1;
282 return 0;
285 static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
287 struct dentry *dentry = filp->f_path.dentry;
288 struct inode *inode = dentry->d_inode;
289 struct ctl_table_header *head = grab_header(inode);
290 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
291 struct ctl_table_header *h = NULL;
292 unsigned long pos;
293 int ret = -EINVAL;
295 if (IS_ERR(head))
296 return PTR_ERR(head);
298 if (table && !table->child) {
299 WARN_ON(1);
300 goto out;
303 table = table ? table->child : head->ctl_table;
305 ret = 0;
306 /* Avoid a switch here: arm builds fail with missing __cmpdi2 */
307 if (filp->f_pos == 0) {
308 if (filldir(dirent, ".", 1, filp->f_pos,
309 inode->i_ino, DT_DIR) < 0)
310 goto out;
311 filp->f_pos++;
313 if (filp->f_pos == 1) {
314 if (filldir(dirent, "..", 2, filp->f_pos,
315 parent_ino(dentry), DT_DIR) < 0)
316 goto out;
317 filp->f_pos++;
319 pos = 2;
321 ret = scan(head, table, &pos, filp, dirent, filldir);
322 if (ret)
323 goto out;
325 for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
326 if (h->attached_to != table)
327 continue;
328 ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
329 if (ret) {
330 sysctl_head_finish(h);
331 break;
334 ret = 1;
335 out:
336 sysctl_head_finish(head);
337 return ret;
340 static int proc_sys_permission(struct inode *inode, int mask)
343 * sysctl entries that are not writeable,
344 * are _NOT_ writeable, capabilities or not.
346 struct ctl_table_header *head;
347 struct ctl_table *table;
348 int error;
350 /* Executable files are not allowed under /proc/sys/ */
351 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
352 return -EACCES;
354 head = grab_header(inode);
355 if (IS_ERR(head))
356 return PTR_ERR(head);
358 table = PROC_I(inode)->sysctl_entry;
359 if (!table) /* global root - r-xr-xr-x */
360 error = mask & MAY_WRITE ? -EACCES : 0;
361 else /* Use the permissions on the sysctl table entry */
362 error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK);
364 sysctl_head_finish(head);
365 return error;
368 static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
370 struct inode *inode = dentry->d_inode;
371 int error;
373 if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
374 return -EPERM;
376 error = inode_change_ok(inode, attr);
377 if (error)
378 return error;
380 if ((attr->ia_valid & ATTR_SIZE) &&
381 attr->ia_size != i_size_read(inode)) {
382 error = vmtruncate(inode, attr->ia_size);
383 if (error)
384 return error;
387 setattr_copy(inode, attr);
388 mark_inode_dirty(inode);
389 return 0;
392 static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
394 struct inode *inode = dentry->d_inode;
395 struct ctl_table_header *head = grab_header(inode);
396 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
398 if (IS_ERR(head))
399 return PTR_ERR(head);
401 generic_fillattr(inode, stat);
402 if (table)
403 stat->mode = (stat->mode & S_IFMT) | table->mode;
405 sysctl_head_finish(head);
406 return 0;
409 static const struct file_operations proc_sys_file_operations = {
410 .open = proc_sys_open,
411 .poll = proc_sys_poll,
412 .read = proc_sys_read,
413 .write = proc_sys_write,
414 .llseek = default_llseek,
417 static const struct file_operations proc_sys_dir_file_operations = {
418 .read = generic_read_dir,
419 .readdir = proc_sys_readdir,
420 .llseek = generic_file_llseek,
423 static const struct inode_operations proc_sys_inode_operations = {
424 .permission = proc_sys_permission,
425 .setattr = proc_sys_setattr,
426 .getattr = proc_sys_getattr,
429 static const struct inode_operations proc_sys_dir_operations = {
430 .lookup = proc_sys_lookup,
431 .permission = proc_sys_permission,
432 .setattr = proc_sys_setattr,
433 .getattr = proc_sys_getattr,
436 static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
438 if (nd->flags & LOOKUP_RCU)
439 return -ECHILD;
440 return !PROC_I(dentry->d_inode)->sysctl->unregistering;
443 static int proc_sys_delete(const struct dentry *dentry)
445 return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
448 static int proc_sys_compare(const struct dentry *parent,
449 const struct inode *pinode,
450 const struct dentry *dentry, const struct inode *inode,
451 unsigned int len, const char *str, const struct qstr *name)
453 struct ctl_table_header *head;
454 /* Although proc doesn't have negative dentries, rcu-walk means
455 * that inode here can be NULL */
456 /* AV: can it, indeed? */
457 if (!inode)
458 return 1;
459 if (name->len != len)
460 return 1;
461 if (memcmp(name->name, str, len))
462 return 1;
463 head = rcu_dereference(PROC_I(inode)->sysctl);
464 return !head || !sysctl_is_seen(head);
467 static const struct dentry_operations proc_sys_dentry_operations = {
468 .d_revalidate = proc_sys_revalidate,
469 .d_delete = proc_sys_delete,
470 .d_compare = proc_sys_compare,
473 int __init proc_sys_init(void)
475 struct proc_dir_entry *proc_sys_root;
477 proc_sys_root = proc_mkdir("sys", NULL);
478 proc_sys_root->proc_iops = &proc_sys_dir_operations;
479 proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
480 proc_sys_root->nlink = 0;
481 return 0;