proc: fix the threaded /proc/self
Long ago when the CLONE_THREAD support first went it someone thought it would be wise to point /proc/self at /proc/<tgid> instead of /proc/<pid>. Given that /proc/<tgid> can return information about a very different task (if enough things have been unshared) then our current process /proc/<tgid> seems blatantly wrong. So far I have yet to think up an example where the current behavior would be advantageous, and I can see several places where it is seriously non-intuitive. We may be stuck with the current broken behavior for backwards compatibility reasons but lets try fixing our ancient bug for the 2.6.25 time frame and see if anyone screams. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: "Guillaume Chazarain" <guichaz@yahoo.fr> Cc: "Pavel Emelyanov" <xemul@openvz.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -2102,22 +2102,22 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
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int buflen)
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{
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struct pid_namespace *ns = dentry->d_sb->s_fs_info;
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pid_t tgid = task_tgid_nr_ns(current, ns);
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pid_t pid = task_pid_nr_ns(current, ns);
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char tmp[PROC_NUMBUF];
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if (!tgid)
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if (!pid)
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return -ENOENT;
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sprintf(tmp, "%d", tgid);
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sprintf(tmp, "%d", pid);
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return vfs_readlink(dentry,buffer,buflen,tmp);
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}
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static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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struct pid_namespace *ns = dentry->d_sb->s_fs_info;
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pid_t tgid = task_tgid_nr_ns(current, ns);
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pid_t pid = task_pid_nr_ns(current, ns);
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char tmp[PROC_NUMBUF];
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if (!tgid)
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if (!pid)
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return ERR_PTR(-ENOENT);
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sprintf(tmp, "%d", task_tgid_nr_ns(current, ns));
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sprintf(tmp, "%d", pid);
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return ERR_PTR(vfs_follow_link(nd,tmp));
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}
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