#include <linux/sched.h> #include <linux/slab.h> #include <linux/pid_namespace.h> #include "internal.h" /* * /proc/thread_self: */ static const char *proc_thread_self_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { struct pid_namespace *ns = inode->i_sb->s_fs_info; pid_t tgid = task_tgid_nr_ns(current, ns); pid_t pid = task_pid_nr_ns(current, ns); char *name; if (!pid) return ERR_PTR(-ENOENT); name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, dentry ? GFP_KERNEL : GFP_ATOMIC); if (unlikely(!name)) return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD); sprintf(name, "%d/task/%d", tgid, pid); set_delayed_call(done, kfree_link, name); return name; } static const struct inode_operations proc_thread_self_inode_operations = { .get_link = proc_thread_self_get_link, }; static unsigned thread_self_inum; int proc_setup_thread_self(struct super_block *s) { struct inode *root_inode = d_inode(s->s_root); struct pid_namespace *ns = s->s_fs_info; struct dentry *thread_self; inode_lock(root_inode); thread_self = d_alloc_name(s->s_root, "thread-self"); if (thread_self) { struct inode *inode = new_inode_pseudo(s); if (inode) { inode->i_ino = thread_self_inum; inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); inode->i_mode = S_IFLNK | S_IRWXUGO; inode->i_uid = GLOBAL_ROOT_UID; inode->i_gid = GLOBAL_ROOT_GID; inode->i_op = &proc_thread_self_inode_operations; d_add(thread_self, inode); } else { dput(thread_self); thread_self = ERR_PTR(-ENOMEM); } } else { thread_self = ERR_PTR(-ENOMEM); } inode_unlock(root_inode); if (IS_ERR(thread_self)) { pr_err("proc_fill_super: can't allocate /proc/thread_self\n"); return PTR_ERR(thread_self); } ns->proc_thread_self = thread_self; return 0; } void __init proc_thread_self_init(void) { proc_alloc_inum(&thread_self_inum); }