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> 677b14db5SEric W. Biederman #include <linux/proc_fs.h> 777b14db5SEric W. Biederman #include <linux/security.h> 877b14db5SEric W. Biederman #include "internal.h" 977b14db5SEric W. Biederman 10d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 1177b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 1203a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 139043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 149043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 1577b14db5SEric W. Biederman 169043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 179043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 1877b14db5SEric W. Biederman { 1977b14db5SEric W. Biederman struct inode *inode; 209043476fSAl Viro struct proc_inode *ei; 2177b14db5SEric W. Biederman 229043476fSAl Viro inode = new_inode(sb); 2377b14db5SEric W. Biederman if (!inode) 2477b14db5SEric W. Biederman goto out; 2577b14db5SEric W. Biederman 2685fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 2785fe4025SChristoph Hellwig 289043476fSAl Viro sysctl_head_get(head); 2977b14db5SEric W. Biederman ei = PROC_I(inode); 309043476fSAl Viro ei->sysctl = head; 319043476fSAl Viro ei->sysctl_entry = table; 329043476fSAl Viro 3377b14db5SEric W. Biederman inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 349043476fSAl Viro inode->i_flags |= S_PRIVATE; /* tell selinux to ignore this inode */ 359043476fSAl Viro inode->i_mode = table->mode; 369043476fSAl Viro if (!table->child) { 379043476fSAl Viro inode->i_mode |= S_IFREG; 3877b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 3977b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 409043476fSAl Viro } else { 419043476fSAl Viro inode->i_mode |= S_IFDIR; 429043476fSAl Viro inode->i_nlink = 0; 439043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 449043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 459043476fSAl Viro } 4677b14db5SEric W. Biederman out: 4777b14db5SEric W. Biederman return inode; 4877b14db5SEric W. Biederman } 4977b14db5SEric W. Biederman 509043476fSAl Viro static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name) 5177b14db5SEric W. Biederman { 5277b14db5SEric W. Biederman int len; 532315ffa0SEric W. Biederman for ( ; p->procname; p++) { 5477b14db5SEric W. Biederman 559043476fSAl Viro if (!p->procname) 5677b14db5SEric W. Biederman continue; 5777b14db5SEric W. Biederman 589043476fSAl Viro len = strlen(p->procname); 5977b14db5SEric W. Biederman if (len != name->len) 6077b14db5SEric W. Biederman continue; 6177b14db5SEric W. Biederman 629043476fSAl Viro if (memcmp(p->procname, name->name, len) != 0) 6377b14db5SEric W. Biederman continue; 6477b14db5SEric W. Biederman 6577b14db5SEric W. Biederman /* I have a match */ 669043476fSAl Viro return p; 6777b14db5SEric W. Biederman } 6877b14db5SEric W. Biederman return NULL; 6977b14db5SEric W. Biederman } 7077b14db5SEric W. Biederman 7181324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 7277b14db5SEric W. Biederman { 739043476fSAl Viro if (PROC_I(inode)->sysctl) 749043476fSAl Viro return sysctl_head_grab(PROC_I(inode)->sysctl); 759043476fSAl Viro else 769043476fSAl Viro return sysctl_head_next(NULL); 7777b14db5SEric W. Biederman } 7877b14db5SEric W. Biederman 7977b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 8077b14db5SEric W. Biederman struct nameidata *nd) 8177b14db5SEric W. Biederman { 829043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 839043476fSAl Viro struct ctl_table *table = PROC_I(dir)->sysctl_entry; 849043476fSAl Viro struct ctl_table_header *h = NULL; 859043476fSAl Viro struct qstr *name = &dentry->d_name; 869043476fSAl Viro struct ctl_table *p; 8777b14db5SEric W. Biederman struct inode *inode; 889043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 8977b14db5SEric W. Biederman 909043476fSAl Viro if (IS_ERR(head)) 919043476fSAl Viro return ERR_CAST(head); 929043476fSAl Viro 939043476fSAl Viro if (table && !table->child) { 949043476fSAl Viro WARN_ON(1); 959043476fSAl Viro goto out; 969043476fSAl Viro } 979043476fSAl Viro 989043476fSAl Viro table = table ? table->child : head->ctl_table; 999043476fSAl Viro 1009043476fSAl Viro p = find_in_table(table, name); 1019043476fSAl Viro if (!p) { 1029043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 1039043476fSAl Viro if (h->attached_to != table) 1049043476fSAl Viro continue; 1059043476fSAl Viro p = find_in_table(h->attached_by, name); 1069043476fSAl Viro if (p) 1079043476fSAl Viro break; 1089043476fSAl Viro } 1099043476fSAl Viro } 1109043476fSAl Viro 1119043476fSAl Viro if (!p) 11277b14db5SEric W. Biederman goto out; 11377b14db5SEric W. Biederman 11477b14db5SEric W. Biederman err = ERR_PTR(-ENOMEM); 1159043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 1169043476fSAl Viro if (h) 1179043476fSAl Viro sysctl_head_finish(h); 1189043476fSAl Viro 11977b14db5SEric W. Biederman if (!inode) 12077b14db5SEric W. Biederman goto out; 12177b14db5SEric W. Biederman 12277b14db5SEric W. Biederman err = NULL; 12377b14db5SEric W. Biederman dentry->d_op = &proc_sys_dentry_operations; 12477b14db5SEric W. Biederman d_add(dentry, inode); 12577b14db5SEric W. Biederman 12677b14db5SEric W. Biederman out: 12777b14db5SEric W. Biederman sysctl_head_finish(head); 12877b14db5SEric W. Biederman return err; 12977b14db5SEric W. Biederman } 13077b14db5SEric W. Biederman 1317708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 1327708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 13377b14db5SEric W. Biederman { 1349043476fSAl Viro struct inode *inode = filp->f_path.dentry->d_inode; 1359043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 1369043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 1372a2da53bSDavid Howells ssize_t error; 1382a2da53bSDavid Howells size_t res; 13977b14db5SEric W. Biederman 1409043476fSAl Viro if (IS_ERR(head)) 1419043476fSAl Viro return PTR_ERR(head); 14277b14db5SEric W. Biederman 14377b14db5SEric W. Biederman /* 14477b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 14577b14db5SEric W. Biederman * and won't be until we finish. 14677b14db5SEric W. Biederman */ 14777b14db5SEric W. Biederman error = -EPERM; 148d7321cd6SPavel Emelyanov if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) 14977b14db5SEric W. Biederman goto out; 15077b14db5SEric W. Biederman 1519043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 1529043476fSAl Viro error = -EINVAL; 1539043476fSAl Viro if (!table->proc_handler) 1549043476fSAl Viro goto out; 1559043476fSAl Viro 15677b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 15777b14db5SEric W. Biederman res = count; 1588d65af78SAlexey Dobriyan error = table->proc_handler(table, write, buf, &res, ppos); 15977b14db5SEric W. Biederman if (!error) 16077b14db5SEric W. Biederman error = res; 16177b14db5SEric W. Biederman out: 16277b14db5SEric W. Biederman sysctl_head_finish(head); 16377b14db5SEric W. Biederman 16477b14db5SEric W. Biederman return error; 16577b14db5SEric W. Biederman } 16677b14db5SEric W. Biederman 1677708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 1687708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 1697708bfb1SPavel Emelyanov { 1707708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 1717708bfb1SPavel Emelyanov } 1727708bfb1SPavel Emelyanov 17377b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 17477b14db5SEric W. Biederman size_t count, loff_t *ppos) 17577b14db5SEric W. Biederman { 1767708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 17777b14db5SEric W. Biederman } 17877b14db5SEric W. Biederman 17977b14db5SEric W. Biederman 18077b14db5SEric W. Biederman static int proc_sys_fill_cache(struct file *filp, void *dirent, 1819043476fSAl Viro filldir_t filldir, 1829043476fSAl Viro struct ctl_table_header *head, 1839043476fSAl Viro struct ctl_table *table) 18477b14db5SEric W. Biederman { 18577b14db5SEric W. Biederman struct dentry *child, *dir = filp->f_path.dentry; 18677b14db5SEric W. Biederman struct inode *inode; 18777b14db5SEric W. Biederman struct qstr qname; 18877b14db5SEric W. Biederman ino_t ino = 0; 18977b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 19077b14db5SEric W. Biederman 19177b14db5SEric W. Biederman qname.name = table->procname; 19277b14db5SEric W. Biederman qname.len = strlen(table->procname); 19377b14db5SEric W. Biederman qname.hash = full_name_hash(qname.name, qname.len); 19477b14db5SEric W. Biederman 19577b14db5SEric W. Biederman child = d_lookup(dir, &qname); 19677b14db5SEric W. Biederman if (!child) { 1979043476fSAl Viro child = d_alloc(dir, &qname); 1989043476fSAl Viro if (child) { 1999043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 2009043476fSAl Viro if (!inode) { 2019043476fSAl Viro dput(child); 2029043476fSAl Viro return -ENOMEM; 2039043476fSAl Viro } else { 2049043476fSAl Viro child->d_op = &proc_sys_dentry_operations; 2059043476fSAl Viro d_add(child, inode); 20677b14db5SEric W. Biederman } 2079043476fSAl Viro } else { 2089043476fSAl Viro return -ENOMEM; 20977b14db5SEric W. Biederman } 21077b14db5SEric W. Biederman } 21177b14db5SEric W. Biederman inode = child->d_inode; 21277b14db5SEric W. Biederman ino = inode->i_ino; 21377b14db5SEric W. Biederman type = inode->i_mode >> 12; 21477b14db5SEric W. Biederman dput(child); 2159043476fSAl Viro return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); 2169043476fSAl Viro } 2179043476fSAl Viro 2189043476fSAl Viro static int scan(struct ctl_table_header *head, ctl_table *table, 2199043476fSAl Viro unsigned long *pos, struct file *file, 2209043476fSAl Viro void *dirent, filldir_t filldir) 2219043476fSAl Viro { 2229043476fSAl Viro 2232315ffa0SEric W. Biederman for (; table->procname; table++, (*pos)++) { 2249043476fSAl Viro int res; 2259043476fSAl Viro 2269043476fSAl Viro /* Can't do anything without a proc name */ 2279043476fSAl Viro if (!table->procname) 2289043476fSAl Viro continue; 2299043476fSAl Viro 2309043476fSAl Viro if (*pos < file->f_pos) 2319043476fSAl Viro continue; 2329043476fSAl Viro 2339043476fSAl Viro res = proc_sys_fill_cache(file, dirent, filldir, head, table); 2349043476fSAl Viro if (res) 2359043476fSAl Viro return res; 2369043476fSAl Viro 2379043476fSAl Viro file->f_pos = *pos + 1; 2389043476fSAl Viro } 2399043476fSAl Viro return 0; 24077b14db5SEric W. Biederman } 24177b14db5SEric W. Biederman 24277b14db5SEric W. Biederman static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) 24377b14db5SEric W. Biederman { 2449043476fSAl Viro struct dentry *dentry = filp->f_path.dentry; 24577b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 2469043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 2479043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 2489043476fSAl Viro struct ctl_table_header *h = NULL; 24977b14db5SEric W. Biederman unsigned long pos; 2509043476fSAl Viro int ret = -EINVAL; 25177b14db5SEric W. Biederman 2529043476fSAl Viro if (IS_ERR(head)) 2539043476fSAl Viro return PTR_ERR(head); 2549043476fSAl Viro 2559043476fSAl Viro if (table && !table->child) { 2569043476fSAl Viro WARN_ON(1); 25777b14db5SEric W. Biederman goto out; 2589043476fSAl Viro } 2599043476fSAl Viro 2609043476fSAl Viro table = table ? table->child : head->ctl_table; 26177b14db5SEric W. Biederman 26277b14db5SEric W. Biederman ret = 0; 26377b14db5SEric W. Biederman /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ 26477b14db5SEric W. Biederman if (filp->f_pos == 0) { 26577b14db5SEric W. Biederman if (filldir(dirent, ".", 1, filp->f_pos, 26677b14db5SEric W. Biederman inode->i_ino, DT_DIR) < 0) 26777b14db5SEric W. Biederman goto out; 26877b14db5SEric W. Biederman filp->f_pos++; 26977b14db5SEric W. Biederman } 27077b14db5SEric W. Biederman if (filp->f_pos == 1) { 27177b14db5SEric W. Biederman if (filldir(dirent, "..", 2, filp->f_pos, 27277b14db5SEric W. Biederman parent_ino(dentry), DT_DIR) < 0) 27377b14db5SEric W. Biederman goto out; 27477b14db5SEric W. Biederman filp->f_pos++; 27577b14db5SEric W. Biederman } 27677b14db5SEric W. Biederman pos = 2; 27777b14db5SEric W. Biederman 2789043476fSAl Viro ret = scan(head, table, &pos, filp, dirent, filldir); 2799043476fSAl Viro if (ret) 28077b14db5SEric W. Biederman goto out; 2819043476fSAl Viro 2829043476fSAl Viro for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { 2839043476fSAl Viro if (h->attached_to != table) 2849043476fSAl Viro continue; 2859043476fSAl Viro ret = scan(h, h->attached_by, &pos, filp, dirent, filldir); 2869043476fSAl Viro if (ret) { 2879043476fSAl Viro sysctl_head_finish(h); 2889043476fSAl Viro break; 28977b14db5SEric W. Biederman } 29077b14db5SEric W. Biederman } 29177b14db5SEric W. Biederman ret = 1; 29277b14db5SEric W. Biederman out: 29377b14db5SEric W. Biederman sysctl_head_finish(head); 29477b14db5SEric W. Biederman return ret; 29577b14db5SEric W. Biederman } 29677b14db5SEric W. Biederman 297e6305c43SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 29877b14db5SEric W. Biederman { 29977b14db5SEric W. Biederman /* 30077b14db5SEric W. Biederman * sysctl entries that are not writeable, 30177b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 30277b14db5SEric W. Biederman */ 303f696a365SMiklos Szeredi struct ctl_table_header *head; 304f696a365SMiklos Szeredi struct ctl_table *table; 30577b14db5SEric W. Biederman int error; 30677b14db5SEric W. Biederman 307f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 308f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 309f696a365SMiklos Szeredi return -EACCES; 310f696a365SMiklos Szeredi 311f696a365SMiklos Szeredi head = grab_header(inode); 3129043476fSAl Viro if (IS_ERR(head)) 3139043476fSAl Viro return PTR_ERR(head); 31477b14db5SEric W. Biederman 315f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 3169043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 3179043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 3189043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 319d7321cd6SPavel Emelyanov error = sysctl_perm(head->root, table, mask); 3209043476fSAl Viro 32177b14db5SEric W. Biederman sysctl_head_finish(head); 32277b14db5SEric W. Biederman return error; 32377b14db5SEric W. Biederman } 32477b14db5SEric W. Biederman 32577b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 32677b14db5SEric W. Biederman { 32777b14db5SEric W. Biederman struct inode *inode = dentry->d_inode; 32877b14db5SEric W. Biederman int error; 32977b14db5SEric W. Biederman 33077b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 33177b14db5SEric W. Biederman return -EPERM; 33277b14db5SEric W. Biederman 33377b14db5SEric W. Biederman error = inode_change_ok(inode, attr); 3341025774cSChristoph Hellwig if (error) 33577b14db5SEric W. Biederman return error; 3361025774cSChristoph Hellwig 3371025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 3381025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 3391025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 3401025774cSChristoph Hellwig if (error) 3411025774cSChristoph Hellwig return error; 3421025774cSChristoph Hellwig } 3431025774cSChristoph Hellwig 3441025774cSChristoph Hellwig setattr_copy(inode, attr); 3451025774cSChristoph Hellwig mark_inode_dirty(inode); 3461025774cSChristoph Hellwig return 0; 34777b14db5SEric W. Biederman } 34877b14db5SEric W. Biederman 3499043476fSAl Viro static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 3509043476fSAl Viro { 3519043476fSAl Viro struct inode *inode = dentry->d_inode; 3529043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 3539043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 3549043476fSAl Viro 3559043476fSAl Viro if (IS_ERR(head)) 3569043476fSAl Viro return PTR_ERR(head); 3579043476fSAl Viro 3589043476fSAl Viro generic_fillattr(inode, stat); 3599043476fSAl Viro if (table) 3609043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 3619043476fSAl Viro 3629043476fSAl Viro sysctl_head_finish(head); 3639043476fSAl Viro return 0; 3649043476fSAl Viro } 3659043476fSAl Viro 36677b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 36777b14db5SEric W. Biederman .read = proc_sys_read, 36877b14db5SEric W. Biederman .write = proc_sys_write, 3696038f373SArnd Bergmann .llseek = default_llseek, 3709043476fSAl Viro }; 3719043476fSAl Viro 3729043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 37377b14db5SEric W. Biederman .readdir = proc_sys_readdir, 3743222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 37577b14db5SEric W. Biederman }; 37677b14db5SEric W. Biederman 37703a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 3789043476fSAl Viro .permission = proc_sys_permission, 3799043476fSAl Viro .setattr = proc_sys_setattr, 3809043476fSAl Viro .getattr = proc_sys_getattr, 3819043476fSAl Viro }; 3829043476fSAl Viro 3839043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 38477b14db5SEric W. Biederman .lookup = proc_sys_lookup, 38577b14db5SEric W. Biederman .permission = proc_sys_permission, 38677b14db5SEric W. Biederman .setattr = proc_sys_setattr, 3879043476fSAl Viro .getattr = proc_sys_getattr, 38877b14db5SEric W. Biederman }; 38977b14db5SEric W. Biederman 39077b14db5SEric W. Biederman static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) 39177b14db5SEric W. Biederman { 3929043476fSAl Viro return !PROC_I(dentry->d_inode)->sysctl->unregistering; 3939043476fSAl Viro } 3949043476fSAl Viro 395fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 3969043476fSAl Viro { 3979043476fSAl Viro return !!PROC_I(dentry->d_inode)->sysctl->unregistering; 3989043476fSAl Viro } 3999043476fSAl Viro 4009043476fSAl Viro static int proc_sys_compare(struct dentry *dir, struct qstr *qstr, 4019043476fSAl Viro struct qstr *name) 4029043476fSAl Viro { 4039043476fSAl Viro struct dentry *dentry = container_of(qstr, struct dentry, d_name); 4049043476fSAl Viro if (qstr->len != name->len) 4059043476fSAl Viro return 1; 4069043476fSAl Viro if (memcmp(qstr->name, name->name, name->len)) 4079043476fSAl Viro return 1; 4089043476fSAl Viro return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl); 40977b14db5SEric W. Biederman } 41077b14db5SEric W. Biederman 411d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 41277b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 4139043476fSAl Viro .d_delete = proc_sys_delete, 4149043476fSAl Viro .d_compare = proc_sys_compare, 41577b14db5SEric W. Biederman }; 41677b14db5SEric W. Biederman 4171e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 41877b14db5SEric W. Biederman { 419e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 420e1675231SAlexey Dobriyan 42177b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 4229043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 4239043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 42477b14db5SEric W. Biederman proc_sys_root->nlink = 0; 42577b14db5SEric W. Biederman return 0; 42677b14db5SEric W. Biederman } 427