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- #include <linux/sched.h>
- #include <linux/slab.h>
- #include <linux/pid_namespace.h>
- #include "internal.h"
- /*
- * /proc/thread_self:
- */
- static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,
- int buflen)
- {
- struct pid_namespace *ns = dentry->d_sb->s_fs_info;
- pid_t tgid = task_tgid_nr_ns(current, ns);
- pid_t pid = task_pid_nr_ns(current, ns);
- char tmp[PROC_NUMBUF + 6 + PROC_NUMBUF];
- if (!pid)
- return -ENOENT;
- sprintf(tmp, "%d/task/%d", tgid, pid);
- return readlink_copy(buffer, buflen, tmp);
- }
- 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 = {
- .readlink = proc_thread_self_readlink,
- .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);
- }
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