projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| e656d8a6 EB |
1 | #include <linux/sched.h> |
| 2 | #include <linux/namei.h> | |
| 0d01ff25 | 3 | #include <linux/slab.h> |
| 021ada7d AV |
4 | #include <linux/pid_namespace.h> |
| 5 | #include "internal.h" | |
| e656d8a6 EB |
6 | |
| 7 | /* | |
| 8 | * /proc/self: | |
| 9 | */ | |
| 10 | static int proc_self_readlink(struct dentry *dentry, char __user *buffer, | |
| 11 | int buflen) | |
| 12 | { | |
| 13 | struct pid_namespace *ns = dentry->d_sb->s_fs_info; | |
| 14 | pid_t tgid = task_tgid_nr_ns(current, ns); | |
| 15 | char tmp[PROC_NUMBUF]; | |
| 16 | if (!tgid) | |
| 17 | return -ENOENT; | |
| 18 | sprintf(tmp, "%d", tgid); | |
| 5d826c84 | 19 | return readlink_copy(buffer, buflen, tmp); |
| e656d8a6 EB |
20 | } |
| 21 | ||
| 22 | static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd) | |
| 23 | { | |
| 24 | struct pid_namespace *ns = dentry->d_sb->s_fs_info; | |
| 25 | pid_t tgid = task_tgid_nr_ns(current, ns); | |
| 26 | char *name = ERR_PTR(-ENOENT); | |
| 27 | if (tgid) { | |
| 28 | /* 11 for max length of signed int in decimal + NULL term */ | |
| 29 | name = kmalloc(12, GFP_KERNEL); | |
| 30 | if (!name) | |
| 31 | name = ERR_PTR(-ENOMEM); | |
| 32 | else | |
| 33 | sprintf(name, "%d", tgid); | |
| 34 | } | |
| 35 | nd_set_link(nd, name); | |
| 36 | return NULL; | |
| 37 | } | |
| 38 | ||
| e656d8a6 EB |
39 | static const struct inode_operations proc_self_inode_operations = { |
| 40 | .readlink = proc_self_readlink, | |
| 41 | .follow_link = proc_self_follow_link, | |
| 87dc800b | 42 | .put_link = kfree_put_link, |
| e656d8a6 EB |
43 | }; |
| 44 | ||
| 021ada7d AV |
45 | static unsigned self_inum; |
| 46 | ||
| 47 | int proc_setup_self(struct super_block *s) | |
| e656d8a6 | 48 | { |
| 021ada7d AV |
49 | struct inode *root_inode = s->s_root->d_inode; |
| 50 | struct pid_namespace *ns = s->s_fs_info; | |
| 51 | struct dentry *self; | |
| 52 | ||
| 53 | mutex_lock(&root_inode->i_mutex); | |
| 54 | self = d_alloc_name(s->s_root, "self"); | |
| 55 | if (self) { | |
| 56 | struct inode *inode = new_inode_pseudo(s); | |
| 57 | if (inode) { | |
| 58 | inode->i_ino = self_inum; | |
| 59 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
| 60 | inode->i_mode = S_IFLNK | S_IRWXUGO; | |
| 61 | inode->i_uid = GLOBAL_ROOT_UID; | |
| 62 | inode->i_gid = GLOBAL_ROOT_GID; | |
| 63 | inode->i_op = &proc_self_inode_operations; | |
| 64 | d_add(self, inode); | |
| 65 | } else { | |
| 66 | dput(self); | |
| 67 | self = ERR_PTR(-ENOMEM); | |
| 68 | } | |
| 69 | } else { | |
| 70 | self = ERR_PTR(-ENOMEM); | |
| 71 | } | |
| 72 | mutex_unlock(&root_inode->i_mutex); | |
| 73 | if (IS_ERR(self)) { | |
| 74 | pr_err("proc_fill_super: can't allocate /proc/self\n"); | |
| 75 | return PTR_ERR(self); | |
| 76 | } | |
| 77 | ns->proc_self = self; | |
| 78 | return 0; | |
| 79 | } | |
| e656d8a6 | 80 | |
| 021ada7d AV |
81 | void __init proc_self_init(void) |
| 82 | { | |
| 83 | proc_alloc_inum(&self_inum); | |
| e656d8a6 | 84 | } |