| 1 | |
| 2 | #include <linux/cache.h>
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| 3 | #include <linux/sched.h>
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| 4 | #include <linux/slab.h>
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| 5 | #include <linux/pid_namespace.h>
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| 6 | #include "internal.h"
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| 7 |
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| 8 | |
| 9 | * /proc/thread_self:
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| 10 |
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| 11 | static const char *proc_thread_self_get_link(struct dentry *dentry,
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| 12 | struct inode *inode,
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| 13 | struct delayed_call *done)
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| 14 | {
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| 15 | struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
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| 16 | pid_t tgid = task_tgid_nr_ns(current, ns);
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| 17 | pid_t pid = task_pid_nr_ns(current, ns);
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| 18 | char *name;
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| 19 |
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| 20 | if (!pid)
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| 21 | return ERR_PTR(-ENOENT);
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| 22 | name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
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| 23 | if (unlikely(!name))
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| 24 | return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
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| 25 | sprintf(name, "%u/task/%u", tgid, pid);
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| 26 | set_delayed_call(done, kfree_link, name);
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| 27 | return name;
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| 28 | }
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| 29 |
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| 30 | static const struct inode_operations proc_thread_self_inode_operations = {
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| 31 | .get_link = proc_thread_self_get_link,
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| 32 | };
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| 33 |
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| 34 | unsigned thread_self_inum __ro_after_init;
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| 35 |
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| 36 | int proc_setup_thread_self(struct super_block *s)
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| 37 | {
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| 38 | struct dentry *thread_self;
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| 39 | int ret = -ENOMEM;
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| 40 |
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| 41 | thread_self = d_alloc_name(s->s_root, "thread-self");
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| 42 | if (thread_self) {
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| 43 | struct inode *inode = new_inode(s);
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| 44 | if (inode) {
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| 45 | inode->i_ino = thread_self_inum;
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| 46 | simple_inode_init_ts(inode);
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| 47 | inode->i_mode = S_IFLNK | S_IRWXUGO;
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| 48 | inode->i_uid = GLOBAL_ROOT_UID;
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| 49 | inode->i_gid = GLOBAL_ROOT_GID;
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| 50 | inode->i_op = &proc_thread_self_inode_operations;
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| 51 | d_make_persistent(thread_self, inode);
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| 52 | ret = 0;
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| 53 | }
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| 54 | dput(thread_self);
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| 55 | }
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| 56 |
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| 57 | if (ret)
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| 58 | pr_err("proc_fill_super: can't allocate /proc/thread-self\n");
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| 59 | return ret;
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| 60 | }
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| 61 |
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| 62 | void __init proc_thread_self_init(void)
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| 63 | {
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| 64 | proc_alloc_inum(&thread_self_inum);
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| 65 | }
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