1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 2e656d8a6SEric W. Biederman #include <linux/sched.h> 30d01ff25SDavid Howells #include <linux/slab.h> 4021ada7dSAl Viro #include <linux/pid_namespace.h> 5021ada7dSAl Viro #include "internal.h" 6e656d8a6SEric W. Biederman 7e656d8a6SEric W. Biederman /* 8e656d8a6SEric W. Biederman * /proc/self: 9e656d8a6SEric W. Biederman */ 106b255391SAl Viro static const char *proc_self_get_link(struct dentry *dentry, 11fceef393SAl Viro struct inode *inode, 12fceef393SAl Viro struct delayed_call *done) 13e656d8a6SEric W. Biederman { 146b255391SAl Viro struct pid_namespace *ns = inode->i_sb->s_fs_info; 15e656d8a6SEric W. Biederman pid_t tgid = task_tgid_nr_ns(current, ns); 16680baacbSAl Viro char *name; 17680baacbSAl Viro 18680baacbSAl Viro if (!tgid) 19680baacbSAl Viro return ERR_PTR(-ENOENT); 20e656d8a6SEric W. Biederman /* 11 for max length of signed int in decimal + NULL term */ 211a384eaaSAl Viro name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC); 221a384eaaSAl Viro if (unlikely(!name)) 231a384eaaSAl Viro return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); 24e656d8a6SEric W. Biederman sprintf(name, "%d", tgid); 25fceef393SAl Viro set_delayed_call(done, kfree_link, name); 26fceef393SAl Viro return name; 27e656d8a6SEric W. Biederman } 28e656d8a6SEric W. Biederman 29e656d8a6SEric W. Biederman static const struct inode_operations proc_self_inode_operations = { 306b255391SAl Viro .get_link = proc_self_get_link, 31e656d8a6SEric W. Biederman }; 32e656d8a6SEric W. Biederman 33021ada7dSAl Viro static unsigned self_inum; 34021ada7dSAl Viro 35021ada7dSAl Viro int proc_setup_self(struct super_block *s) 36021ada7dSAl Viro { 372b0143b5SDavid Howells struct inode *root_inode = d_inode(s->s_root); 38021ada7dSAl Viro struct pid_namespace *ns = s->s_fs_info; 39021ada7dSAl Viro struct dentry *self; 40021ada7dSAl Viro 415955102cSAl Viro inode_lock(root_inode); 42021ada7dSAl Viro self = d_alloc_name(s->s_root, "self"); 43021ada7dSAl Viro if (self) { 44021ada7dSAl Viro struct inode *inode = new_inode_pseudo(s); 45021ada7dSAl Viro if (inode) { 46021ada7dSAl Viro inode->i_ino = self_inum; 47078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 48021ada7dSAl Viro inode->i_mode = S_IFLNK | S_IRWXUGO; 49021ada7dSAl Viro inode->i_uid = GLOBAL_ROOT_UID; 50021ada7dSAl Viro inode->i_gid = GLOBAL_ROOT_GID; 51021ada7dSAl Viro inode->i_op = &proc_self_inode_operations; 52021ada7dSAl Viro d_add(self, inode); 53021ada7dSAl Viro } else { 54021ada7dSAl Viro dput(self); 55021ada7dSAl Viro self = ERR_PTR(-ENOMEM); 56021ada7dSAl Viro } 57021ada7dSAl Viro } else { 58021ada7dSAl Viro self = ERR_PTR(-ENOMEM); 59021ada7dSAl Viro } 605955102cSAl Viro inode_unlock(root_inode); 61021ada7dSAl Viro if (IS_ERR(self)) { 62021ada7dSAl Viro pr_err("proc_fill_super: can't allocate /proc/self\n"); 63021ada7dSAl Viro return PTR_ERR(self); 64021ada7dSAl Viro } 65021ada7dSAl Viro ns->proc_self = self; 66021ada7dSAl Viro return 0; 67021ada7dSAl Viro } 68021ada7dSAl Viro 69e656d8a6SEric W. Biederman void __init proc_self_init(void) 70e656d8a6SEric W. Biederman { 71021ada7dSAl Viro proc_alloc_inum(&self_inum); 72e656d8a6SEric W. Biederman } 73