[PATCH] proc: Make the generation of the self symlink table driven

[deliverable/linux.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6d00ccc48c1cb43cf6b2f05fb063d43cb3cf4a1c..7832efbd43a66bb684c340f73092b7e9f111a4ad 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1673,6 +1673,108 @@ static struct inode_operations proc_self_inode_operations = {
        .follow_link    = proc_self_follow_link,
 };
 
+/*
+ * 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
  */
@@ -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;