177b14db5SEric W. Biederman /* 277b14db5SEric W. Biederman * /proc/sys support 377b14db5SEric W. Biederman */ 41e0edd3fSAlexey Dobriyan #include <linux/init.h> 577b14db5SEric W. Biederman #include <linux/sysctl.h> 6f1ecf068SLucas De Marchi #include <linux/poll.h> 777b14db5SEric W. Biederman #include <linux/proc_fs.h> 877b14db5SEric W. Biederman #include <linux/security.h> 934286d66SNick Piggin #include <linux/namei.h> 1077b14db5SEric W. Biederman #include "internal.h" 1177b14db5SEric W. Biederman 12d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1377b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 1403a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 159043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 169043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 1777b14db5SEric W. Biederman 18f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 19f1ecf068SLucas De Marchi { 20f1ecf068SLucas De Marchi if (!poll) 21f1ecf068SLucas De Marchi return; 22f1ecf068SLucas De Marchi 23f1ecf068SLucas De Marchi atomic_inc(&poll->event); 24f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 25f1ecf068SLucas De Marchi } 26f1ecf068SLucas De Marchi 279043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 289043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 2977b14db5SEric W. Biederman { 3077b14db5SEric W. Biederman struct inode *inode; 319043476fSAl Viro struct proc_inode *ei; 3277b14db5SEric W. Biederman 339043476fSAl Viro inode = new_inode(sb); 3477b14db5SEric W. Biederman if (!inode) 3577b14db5SEric W. Biederman goto out; 3677b14db5SEric W. Biederman 3785fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 3885fe4025SChristoph Hellwig 399043476fSAl Viro sysctl_head_get(head); 4077b14db5SEric W. Biederman ei = PROC_I(inode); 419043476fSAl Viro ei->sysctl = head; 429043476fSAl Viro ei->sysctl_entry = table; 439043476fSAl Viro 4477b14db5SEric W. Biederman inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 459043476fSAl Viro inode->i_mode = table->mode; 469043476fSAl Viro if (!table->child) { 479043476fSAl Viro inode->i_mode |= S_IFREG; 4877b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 4977b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 509043476fSAl Viro } else { 519043476fSAl Viro inode->i_mode |= S_IFDIR; 526d6b77f1SMiklos Szeredi clear_nlink(inode); 539043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 549043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 559043476fSAl Viro } 5677b14db5SEric W. Biederman out: 5777b14db5SEric W. Biederman return inode; 5877b14db5SEric W. Biederman } 5977b14db5SEric W. Biederman 609043476fSAl Viro static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name) 6177b14db5SEric W. Biederman { 622315ffa0SEric W. Biederman for ( ; p->procname; p++) { 6336885d7bSLucas De Marchi if (strlen(p->procname) != name->len) 6477b14db5SEric W. Biederman continue; 6577b14db5SEric W. Biederman 6636885d7bSLucas De Marchi if (memcmp(p->procname, name->name, name->len) != 0) 6777b14db5SEric W. Biederman continue; 6877b14db5SEric W. Biederman 6977b14db5SEric W. Biederman /* I have a match */ 709043476fSAl Viro return p; 7177b14db5SEric W. Biederman } 7277b14db5SEric W. Biederman return NULL; 7377b14db5SEric W. Biederman } 7477b14db5SEric W. Biederman 7581324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 7677b14db5SEric W. Biederman { 779043476fSAl Viro if (PROC_I(inode)->sysctl) 789043476fSAl Viro return sysctl_head_grab(PROC_I(inode)->sysctl); 799043476fSAl Viro else 809043476fSAl Viro return sysctl_head_next(NULL); 8177b14db5SEric W. Biederman } 8277b14db5SEric W. Biederman 8377b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 8477b14db5SEric W. Biederman struct nameidata *nd) 8577b14db5SEric W. Biederman { 869043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 879043476fSAl Viro struct ctl_table *table = PROC_I(dir)->sysctl_entry; 889043476fSAl Viro struct ctl_table_header *h = NULL; 899043476fSAl Viro struct qstr *name = &dentry->d_name; 909043476fSAl Viro struct ctl_table *p; 9177b14db5SEric W. Biederman struct inode *inode; 929043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 9377b14db5SEric W. Biederman 949043476fSAl Viro if (IS_ERR(head)) 959043476fSAl Viro return ERR_CAST(head); 969043476fSAl Viro 979043476fSAl Viro if (table && !table->child) { 989043476fSAl Viro WARN_ON(1); 999043476fSAl Viro goto out; 1009043476fSAl Viro } 1019043476fSAl Viro 1029043476fSAl Viro table = table ? table->child : head->ctl_table; 1039043476fSAl Viro 1049043476fSAl Viro p = find_in_table(table, name); 1059043476fSAl Viro if (!p) { 1069043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 1079043476fSAl Viro if (h->attached_to != table) 1089043476fSAl Viro continue; 1099043476fSAl Viro p = find_in_table(h->attached_by, name); 1109043476fSAl Viro if (p) 1119043476fSAl Viro break; 1129043476fSAl Viro } 1139043476fSAl Viro } 1149043476fSAl Viro 1159043476fSAl Viro if (!p) 11677b14db5SEric W. Biederman goto out; 11777b14db5SEric W. Biederman 11877b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 1199043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 1209043476fSAl Viro if (h) 1219043476fSAl Viro sysctl_head_finish(h); 1229043476fSAl Viro 12377b14db5SEric W. Biederman if (!inode) 12477b14db5SEric W. Biederman goto out; 12577b14db5SEric W. Biederman 12677b14db5SEric W. Biederman err = NULL; 127fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 12877b14db5SEric W. Biederman d_add(dentry, inode); 12977b14db5SEric W. Biederman 13077b14db5SEric W. Biederman out: 13177b14db5SEric W. Biederman sysctl_head_finish(head); 13277b14db5SEric W. Biederman return err; 13377b14db5SEric W. Biederman } 13477b14db5SEric W. Biederman 1357708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 1367708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 13777b14db5SEric W. Biederman { 1389043476fSAl Viro struct inode *inode = filp->f_path.dentry->d_inode; 1399043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 1409043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 1412a2da53bSDavid Howells ssize_t error; 1422a2da53bSDavid Howells size_t res; 14377b14db5SEric W. Biederman 1449043476fSAl Viro if (IS_ERR(head)) 1459043476fSAl Viro return PTR_ERR(head); 14677b14db5SEric W. Biederman 14777b14db5SEric W. Biederman /* 14877b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 14977b14db5SEric W. Biederman * and won't be until we finish. 15077b14db5SEric W. Biederman */ 15177b14db5SEric W. Biederman error = -EPERM; 152d7321cd6SPavel Emelyanov if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) 15377b14db5SEric W. Biederman goto out; 15477b14db5SEric W. Biederman 1559043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 1569043476fSAl Viro error = -EINVAL; 1579043476fSAl Viro if (!table->proc_handler) 1589043476fSAl Viro goto out; 1599043476fSAl Viro 16077b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 16177b14db5SEric W. Biederman res = count; 1628d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 16377b14db5SEric W. Biederman if (!error) 16477b14db5SEric W. Biederman error = res; 16577b14db5SEric W. Biederman out: 16677b14db5SEric W. Biederman sysctl_head_finish(head); 16777b14db5SEric W. Biederman 16877b14db5SEric W. Biederman return error; 16977b14db5SEric W. Biederman } 17077b14db5SEric W. Biederman 1717708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 1727708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 1737708bfb1SPavel Emelyanov { 1747708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 1757708bfb1SPavel Emelyanov } 1767708bfb1SPavel Emelyanov 17777b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 17877b14db5SEric W. Biederman size_t count, loff_t *ppos) 17977b14db5SEric W. Biederman { 1807708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 18177b14db5SEric W. Biederman } 18277b14db5SEric W. Biederman 183f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 184f1ecf068SLucas De Marchi { 185f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 186f1ecf068SLucas De Marchi 187f1ecf068SLucas De Marchi if (table->poll) 188f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 189f1ecf068SLucas De Marchi 190f1ecf068SLucas De Marchi return 0; 191f1ecf068SLucas De Marchi } 192f1ecf068SLucas De Marchi 193f1ecf068SLucas De Marchi static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) 194f1ecf068SLucas De Marchi { 195f1ecf068SLucas De Marchi struct inode *inode = filp->f_path.dentry->d_inode; 196f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 197f1ecf068SLucas De Marchi unsigned long event = (unsigned long)filp->private_data; 198f1ecf068SLucas De Marchi unsigned int ret = DEFAULT_POLLMASK; 199f1ecf068SLucas De Marchi 200f1ecf068SLucas De Marchi if (!table->proc_handler) 201f1ecf068SLucas De Marchi goto out; 202f1ecf068SLucas De Marchi 203f1ecf068SLucas De Marchi if (!table->poll) 204f1ecf068SLucas De Marchi goto out; 205f1ecf068SLucas De Marchi 206f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 207f1ecf068SLucas De Marchi 208f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 209f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 210f1ecf068SLucas De Marchi ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; 211f1ecf068SLucas De Marchi } 212f1ecf068SLucas De Marchi 213f1ecf068SLucas De Marchi out: 214f1ecf068SLucas De Marchi return ret; 215f1ecf068SLucas De Marchi } 21677b14db5SEric W. Biederman 21777b14db5SEric W. Biederman static int proc_sys_fill_cache(struct file *filp, void *dirent, 2189043476fSAl Viro filldir_t filldir, 2199043476fSAl Viro struct ctl_table_header *head, 2209043476fSAl Viro struct ctl_table *table) 22177b14db5SEric W. Biederman { 22277b14db5SEric W. Biederman struct dentry *child, *dir = filp->f_path.dentry; 22377b14db5SEric W. Biederman struct inode *inode; 22477b14db5SEric W. Biederman struct qstr qname; 22577b14db5SEric W. Biederman ino_t ino = 0; 22677b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 22777b14db5SEric W. Biederman 22877b14db5SEric W. Biederman qname.name = table->procname; 22977b14db5SEric W. Biederman qname.len = strlen(table->procname); 23077b14db5SEric W. Biederman qname.hash = full_name_hash(qname.name, qname.len); 23177b14db5SEric W. Biederman 23277b14db5SEric W. Biederman child = d_lookup(dir, &qname); 23377b14db5SEric W. Biederman if (!child) { 2349043476fSAl Viro child = d_alloc(dir, &qname); 2359043476fSAl Viro if (child) { 2369043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 2379043476fSAl Viro if (!inode) { 2389043476fSAl Viro dput(child); 2399043476fSAl Viro return -ENOMEM; 2409043476fSAl Viro } else { 241fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 2429043476fSAl Viro d_add(child, inode); 24377b14db5SEric W. Biederman } 2449043476fSAl Viro } else { 2459043476fSAl Viro return -ENOMEM; 24677b14db5SEric W. Biederman } 24777b14db5SEric W. Biederman } 24877b14db5SEric W. Biederman inode = child->d_inode; 24977b14db5SEric W. Biederman ino = inode->i_ino; 25077b14db5SEric W. Biederman type = inode->i_mode >> 12; 25177b14db5SEric W. Biederman dput(child); 2529043476fSAl Viro return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); 2539043476fSAl Viro } 2549043476fSAl Viro 2559043476fSAl Viro static int scan(struct ctl_table_header *head, ctl_table *table, 2569043476fSAl Viro unsigned long *pos, struct file *file, 2579043476fSAl Viro void *dirent, filldir_t filldir) 2589043476fSAl Viro { 2599043476fSAl Viro 2602315ffa0SEric W. Biederman for (; table->procname; table++, (*pos)++) { 2619043476fSAl Viro int res; 2629043476fSAl Viro 2639043476fSAl Viro if (*pos < file->f_pos) 2649043476fSAl Viro continue; 2659043476fSAl Viro 2669043476fSAl Viro res = proc_sys_fill_cache(file, dirent, filldir, head, table); 2679043476fSAl Viro if (res) 2689043476fSAl Viro return res; 2699043476fSAl Viro 2709043476fSAl Viro file->f_pos = *pos + 1; 2719043476fSAl Viro } 2729043476fSAl Viro return 0; 27377b14db5SEric W. Biederman } 27477b14db5SEric W. Biederman 27577b14db5SEric W. Biederman static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) 27677b14db5SEric W. Biederman { 2779043476fSAl Viro struct dentry *dentry = filp->f_path.dentry; 27877b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 2799043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 2809043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 2819043476fSAl Viro struct ctl_table_header *h = NULL; 28277b14db5SEric W. Biederman unsigned long pos; 2839043476fSAl Viro int ret = -EINVAL; 28477b14db5SEric W. Biederman 2859043476fSAl Viro if (IS_ERR(head)) 2869043476fSAl Viro return PTR_ERR(head); 2879043476fSAl Viro 2889043476fSAl Viro if (table && !table->child) { 2899043476fSAl Viro WARN_ON(1); 29077b14db5SEric W. Biederman goto out; 2919043476fSAl Viro } 2929043476fSAl Viro 2939043476fSAl Viro table = table ? table->child : head->ctl_table; 29477b14db5SEric W. Biederman 29577b14db5SEric W. Biederman ret = 0; 29677b14db5SEric W. Biederman /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ 29777b14db5SEric W. Biederman if (filp->f_pos == 0) { 29877b14db5SEric W. Biederman if (filldir(dirent, ".", 1, filp->f_pos, 29977b14db5SEric W. Biederman inode->i_ino, DT_DIR) < 0) 30077b14db5SEric W. Biederman goto out; 30177b14db5SEric W. Biederman filp->f_pos++; 30277b14db5SEric W. Biederman } 30377b14db5SEric W. Biederman if (filp->f_pos == 1) { 30477b14db5SEric W. Biederman if (filldir(dirent, "..", 2, filp->f_pos, 30577b14db5SEric W. Biederman parent_ino(dentry), DT_DIR) < 0) 30677b14db5SEric W. Biederman goto out; 30777b14db5SEric W. Biederman filp->f_pos++; 30877b14db5SEric W. Biederman } 30977b14db5SEric W. Biederman pos = 2; 31077b14db5SEric W. Biederman 3119043476fSAl Viro ret = scan(head, table, &pos, filp, dirent, filldir); 3129043476fSAl Viro if (ret) 31377b14db5SEric W. Biederman goto out; 3149043476fSAl Viro 3159043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 3169043476fSAl Viro if (h->attached_to != table) 3179043476fSAl Viro continue; 3189043476fSAl Viro ret = scan(h, h->attached_by, &pos, filp, dirent, filldir); 3199043476fSAl Viro if (ret) { 3209043476fSAl Viro sysctl_head_finish(h); 3219043476fSAl Viro break; 32277b14db5SEric W. Biederman } 32377b14db5SEric W. Biederman } 32477b14db5SEric W. Biederman ret = 1; 32577b14db5SEric W. Biederman out: 32677b14db5SEric W. Biederman sysctl_head_finish(head); 32777b14db5SEric W. Biederman return ret; 32877b14db5SEric W. Biederman } 32977b14db5SEric W. Biederman 33010556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 33177b14db5SEric W. Biederman { 33277b14db5SEric W. Biederman /* 33377b14db5SEric W. Biederman * sysctl entries that are not writeable, 33477b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 33577b14db5SEric W. Biederman */ 336f696a365SMiklos Szeredi struct ctl_table_header *head; 337f696a365SMiklos Szeredi struct ctl_table *table; 33877b14db5SEric W. Biederman int error; 33977b14db5SEric W. Biederman 340f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 341f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 342f696a365SMiklos Szeredi return -EACCES; 343f696a365SMiklos Szeredi 344f696a365SMiklos Szeredi head = grab_header(inode); 3459043476fSAl Viro if (IS_ERR(head)) 3469043476fSAl Viro return PTR_ERR(head); 34777b14db5SEric W. Biederman 348f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 3499043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 3509043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 3519043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 3521fc0f78cSAl Viro error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK); 3539043476fSAl Viro 35477b14db5SEric W. Biederman sysctl_head_finish(head); 35577b14db5SEric W. Biederman return error; 35677b14db5SEric W. Biederman } 35777b14db5SEric W. Biederman 35877b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 35977b14db5SEric W. Biederman { 36077b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 36177b14db5SEric W. Biederman int error; 36277b14db5SEric W. Biederman 36377b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 36477b14db5SEric W. Biederman return -EPERM; 36577b14db5SEric W. Biederman 36677b14db5SEric W. Biederman error = inode_change_ok(inode, attr); 3671025774cSChristoph Hellwig if (error) 36877b14db5SEric W. Biederman return error; 3691025774cSChristoph Hellwig 3701025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 3711025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 3721025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 3731025774cSChristoph Hellwig if (error) 3741025774cSChristoph Hellwig return error; 3751025774cSChristoph Hellwig } 3761025774cSChristoph Hellwig 3771025774cSChristoph Hellwig setattr_copy(inode, attr); 3781025774cSChristoph Hellwig mark_inode_dirty(inode); 3791025774cSChristoph Hellwig return 0; 38077b14db5SEric W. Biederman } 38177b14db5SEric W. Biederman 3829043476fSAl Viro static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 3839043476fSAl Viro { 3849043476fSAl Viro struct inode *inode = dentry->d_inode; 3859043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 3869043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 3879043476fSAl Viro 3889043476fSAl Viro if (IS_ERR(head)) 3899043476fSAl Viro return PTR_ERR(head); 3909043476fSAl Viro 3919043476fSAl Viro generic_fillattr(inode, stat); 3929043476fSAl Viro if (table) 3939043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 3949043476fSAl Viro 3959043476fSAl Viro sysctl_head_finish(head); 3969043476fSAl Viro return 0; 3979043476fSAl Viro } 3989043476fSAl Viro 39977b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 400f1ecf068SLucas De Marchi .open = proc_sys_open, 401f1ecf068SLucas De Marchi .poll = proc_sys_poll, 40277b14db5SEric W. Biederman .read = proc_sys_read, 40377b14db5SEric W. Biederman .write = proc_sys_write, 4046038f373SArnd Bergmann .llseek = default_llseek, 4059043476fSAl Viro }; 4069043476fSAl Viro 4079043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 408887df078SPavel Emelyanov .read = generic_read_dir, 40977b14db5SEric W. Biederman .readdir = proc_sys_readdir, 4103222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 41177b14db5SEric W. Biederman }; 41277b14db5SEric W. Biederman 41303a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 4149043476fSAl Viro .permission = proc_sys_permission, 4159043476fSAl Viro .setattr = proc_sys_setattr, 4169043476fSAl Viro .getattr = proc_sys_getattr, 4179043476fSAl Viro }; 4189043476fSAl Viro 4199043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 42077b14db5SEric W. Biederman .lookup = proc_sys_lookup, 42177b14db5SEric W. Biederman .permission = proc_sys_permission, 42277b14db5SEric W. Biederman .setattr = proc_sys_setattr, 4239043476fSAl Viro .getattr = proc_sys_getattr, 42477b14db5SEric W. Biederman }; 42577b14db5SEric W. Biederman 42677b14db5SEric W. Biederman static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) 42777b14db5SEric W. Biederman { 42834286d66SNick Piggin if (nd->flags & LOOKUP_RCU) 42934286d66SNick Piggin return -ECHILD; 4309043476fSAl Viro return !PROC_I(dentry->d_inode)->sysctl->unregistering; 4319043476fSAl Viro } 4329043476fSAl Viro 433fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 4349043476fSAl Viro { 4359043476fSAl Viro return !!PROC_I(dentry->d_inode)->sysctl->unregistering; 4369043476fSAl Viro } 4379043476fSAl Viro 438621e155aSNick Piggin static int proc_sys_compare(const struct dentry *parent, 439621e155aSNick Piggin const struct inode *pinode, 440621e155aSNick Piggin const struct dentry *dentry, const struct inode *inode, 441621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 4429043476fSAl Viro { 443dfef6dcdSAl Viro struct ctl_table_header *head; 44431e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 44531e6b01fSNick Piggin * that inode here can be NULL */ 446dfef6dcdSAl Viro /* AV: can it, indeed? */ 44731e6b01fSNick Piggin if (!inode) 448dfef6dcdSAl Viro return 1; 449621e155aSNick Piggin if (name->len != len) 4509043476fSAl Viro return 1; 451621e155aSNick Piggin if (memcmp(name->name, str, len)) 4529043476fSAl Viro return 1; 453dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 454dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 45577b14db5SEric W. Biederman } 45677b14db5SEric W. Biederman 457d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 45877b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 4599043476fSAl Viro .d_delete = proc_sys_delete, 4609043476fSAl Viro .d_compare = proc_sys_compare, 46177b14db5SEric W. Biederman }; 46277b14db5SEric W. Biederman 4631e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 46477b14db5SEric W. Biederman { 465e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 466e1675231SAlexey Dobriyan 46777b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 4689043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 4699043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 47077b14db5SEric W. Biederman proc_sys_root->nlink = 0; 471de4e83bdSEric W. Biederman 472de4e83bdSEric W. Biederman return sysctl_init(); 47377b14db5SEric W. Biederman } 474