Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / proc / self.c

diff --git a/kernel/fs/proc/self.c b/kernel/fs/proc/self.c
new file mode 100644 (file)
index 0000000..6195b4a
--- /dev/null
+++ b/kernel/fs/proc/self.c
@@ -0,0 +1,84 @@
+#include <linux/sched.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/pid_namespace.h>
+#include "internal.h"
+
+/*
+ * /proc/self:
+ */
+static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
+                             int buflen)
+{
+       struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+       pid_t tgid = task_tgid_nr_ns(current, ns);
+       char tmp[PROC_NUMBUF];
+       if (!tgid)
+               return -ENOENT;
+       sprintf(tmp, "%d", tgid);
+       return readlink_copy(buffer, buflen, tmp);
+}
+
+static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+       pid_t tgid = task_tgid_nr_ns(current, ns);
+       char *name = ERR_PTR(-ENOENT);
+       if (tgid) {
+               /* 11 for max length of signed int in decimal + NULL term */
+               name = kmalloc(12, GFP_KERNEL);
+               if (!name)
+                       name = ERR_PTR(-ENOMEM);
+               else
+                       sprintf(name, "%d", tgid);
+       }
+       nd_set_link(nd, name);
+       return NULL;
+}
+
+static const struct inode_operations proc_self_inode_operations = {
+       .readlink       = proc_self_readlink,
+       .follow_link    = proc_self_follow_link,
+       .put_link       = kfree_put_link,
+};
+
+static unsigned self_inum;
+
+int proc_setup_self(struct super_block *s)
+{
+       struct inode *root_inode = d_inode(s->s_root);
+       struct pid_namespace *ns = s->s_fs_info;
+       struct dentry *self;
+       
+       mutex_lock(&root_inode->i_mutex);
+       self = d_alloc_name(s->s_root, "self");
+       if (self) {
+               struct inode *inode = new_inode_pseudo(s);
+               if (inode) {
+                       inode->i_ino = self_inum;
+                       inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+                       inode->i_mode = S_IFLNK | S_IRWXUGO;
+                       inode->i_uid = GLOBAL_ROOT_UID;
+                       inode->i_gid = GLOBAL_ROOT_GID;
+                       inode->i_op = &proc_self_inode_operations;
+                       d_add(self, inode);
+               } else {
+                       dput(self);
+                       self = ERR_PTR(-ENOMEM);
+               }
+       } else {
+               self = ERR_PTR(-ENOMEM);
+       }
+       mutex_unlock(&root_inode->i_mutex);
+       if (IS_ERR(self)) {
+               pr_err("proc_fill_super: can't allocate /proc/self\n");
+               return PTR_ERR(self);
+       }
+       ns->proc_self = self;
+       return 0;
+}
+
+void __init proc_self_init(void)
+{
+       proc_alloc_inum(&self_inum);
+}