1 files changed, 111 insertions, 22 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6d00ccc48c1c..7832efbd43a6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1674,6 +1674,108 @@ static struct inode_operations proc_self_inode_operations = {
 };
 
 /*
+ * proc base
+ *
+ * These are the directory entries in the root directory of /proc
+ * that properly belong to the /proc filesystem, as they describe
+ * describe something that is process related.
+ */
+static struct pid_entry proc_base_stuff[] = {
+        NOD(PROC_TGID_INO,      "self", S_IFLNK|S_IRWXUGO,
+                &proc_self_inode_operations, NULL, {}),
+        {}
+};
+
+/*
+ *      Exceptional case: normally we are not allowed to unhash a busy
+ * directory. In this case, however, we can do it - no aliasing problems
+ * due to the way we treat inodes.
+ */
+static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+        struct inode *inode = dentry->d_inode;
+        struct task_struct *task = get_proc_task(inode);
+        if (task) {
+                put_task_struct(task);
+                return 1;
+        }
+        d_drop(dentry);
+        return 0;
+}
+
+static struct dentry_operations proc_base_dentry_operations =
+{
+        .d_revalidate   = proc_base_revalidate,
+        .d_delete       = pid_delete_dentry,
+};
+
+static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
+{
+        struct inode *inode;
+        struct dentry *error;
+        struct task_struct *task = get_proc_task(dir);
+        struct pid_entry *p;
+        struct proc_inode *ei;
+
+        error = ERR_PTR(-ENOENT);
+        inode = NULL;
+
+        if (!task)
+                goto out_no_task;
+
+        /* Lookup the directory entry */
+        for (p = proc_base_stuff; p->name; p++) {
+                if (p->len != dentry->d_name.len)
+                        continue;
+                if (!memcmp(dentry->d_name.name, p->name, p->len))
+                        break;
+        }
+        if (!p->name)
+                goto out;
+
+        /* Allocate the inode */
+        error = ERR_PTR(-ENOMEM);
+        inode = new_inode(dir->i_sb);
+        if (!inode)
+                goto out;
+
+        /* Initialize the inode */
+        ei = PROC_I(inode);
+        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+        inode->i_ino = fake_ino(0, p->type);
+
+        /*
+         * grab the reference to the task.
+         */
+        ei->pid = get_pid(task_pid(task));
+        if (!ei->pid)
+                goto out_iput;
+
+        inode->i_uid = 0;
+        inode->i_gid = 0;
+        inode->i_mode = p->mode;
+        if (S_ISDIR(inode->i_mode))
+                inode->i_nlink = 2;
+        if (S_ISLNK(inode->i_mode))
+                inode->i_size = 64;
+        if (p->iop)
+                inode->i_op = p->iop;
+        if (p->fop)
+                inode->i_fop = p->fop;
+        ei->op = p->op;
+        dentry->d_op = &proc_base_dentry_operations;
+        d_add(dentry, inode);
+        error = NULL;
+out:
+        put_task_struct(task);
+out_no_task:
+        return error;
+out_iput:
+        iput(inode);
+        goto out;
+}
+
+/*
  * Thread groups
  */
 static struct file_operations proc_task_operations;
@@ -1819,24 +1921,12 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct
         struct dentry *result = ERR_PTR(-ENOENT);
         struct task_struct *task;
         struct inode *inode;
-        struct proc_inode *ei;
         unsigned tgid;
 
-        if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
-                inode = new_inode(dir->i_sb);
-                if (!inode)
-                        return ERR_PTR(-ENOMEM);
-                ei = PROC_I(inode);
-                inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-                inode->i_ino = fake_ino(0, PROC_TGID_INO);
-                ei->pde = NULL;
-                inode->i_mode = S_IFLNK|S_IRWXUGO;
-                inode->i_uid = inode->i_gid = 0;
-                inode->i_size = 64;
-                inode->i_op = &proc_self_inode_operations;
-                d_add(dentry, inode);
-                return NULL;
-        }
+        result = proc_base_lookup(dir, dentry);
+        if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT)
+                goto out;
+
         tgid = name_to_int(dentry);
         if (tgid == ~0U)
                 goto out;
@@ -1922,12 +2012,11 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
         struct task_struct *task;
         int tgid;
 
-        if (!nr) {
-                ino_t ino = fake_ino(0,PROC_TGID_INO);
-                if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
-                        return 0;
-                filp->f_pos++;
-                nr++;
+        for (; nr < (ARRAY_SIZE(proc_base_stuff) - 1); filp->f_pos++, nr++) {
+                struct pid_entry *p = &proc_base_stuff[nr];
+                if (filldir(dirent, p->name, p->len, filp->f_pos,
+                            fake_ino(0, p->type), p->mode >> 12) < 0)
+                        goto out;
         }
 
         tgid = filp->f_pos - TGID_OFFSET;