Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / init / do_mounts_initrd.c

diff --git a/kernel/init/do_mounts_initrd.c b/kernel/init/do_mounts_initrd.c
new file mode 100644 (file)
index 0000000..3e0878e
--- /dev/null
+++ b/kernel/init/do_mounts_initrd.c
@@ -0,0 +1,137 @@
+/*
+ * Many of the syscalls used in this file expect some of the arguments
+ * to be __user pointers not __kernel pointers.  To limit the sparse
+ * noise, turn off sparse checking for this file.
+ */
+#ifdef __CHECKER__
+#undef __CHECKER__
+#warning "Sparse checking disabled for this file"
+#endif
+
+#include <linux/unistd.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/minix_fs.h>
+#include <linux/romfs_fs.h>
+#include <linux/initrd.h>
+#include <linux/sched.h>
+#include <linux/freezer.h>
+#include <linux/kmod.h>
+
+#include "do_mounts.h"
+
+unsigned long initrd_start, initrd_end;
+int initrd_below_start_ok;
+unsigned int real_root_dev;    /* do_proc_dointvec cannot handle kdev_t */
+static int __initdata mount_initrd = 1;
+
+static int __init no_initrd(char *str)
+{
+       mount_initrd = 0;
+       return 1;
+}
+
+__setup("noinitrd", no_initrd);
+
+static int init_linuxrc(struct subprocess_info *info, struct cred *new)
+{
+       sys_unshare(CLONE_FS | CLONE_FILES);
+       /* stdin/stdout/stderr for /linuxrc */
+       sys_open("/dev/console", O_RDWR, 0);
+       sys_dup(0);
+       sys_dup(0);
+       /* move initrd over / and chdir/chroot in initrd root */
+       sys_chdir("/root");
+       sys_mount(".", "/", NULL, MS_MOVE, NULL);
+       sys_chroot(".");
+       sys_setsid();
+       return 0;
+}
+
+static void __init handle_initrd(void)
+{
+       struct subprocess_info *info;
+       static char *argv[] = { "linuxrc", NULL, };
+       extern char *envp_init[];
+       int error;
+
+       real_root_dev = new_encode_dev(ROOT_DEV);
+       create_dev("/dev/root.old", Root_RAM0);
+       /* mount initrd on rootfs' /root */
+       mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
+       sys_mkdir("/old", 0700);
+       sys_chdir("/old");
+
+       /* try loading default modules from initrd */
+       load_default_modules();
+
+       /*
+        * In case that a resume from disk is carried out by linuxrc or one of
+        * its children, we need to tell the freezer not to wait for us.
+        */
+       current->flags |= PF_FREEZER_SKIP;
+
+       info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
+                                        GFP_KERNEL, init_linuxrc, NULL, NULL);
+       if (!info)
+               return;
+       call_usermodehelper_exec(info, UMH_WAIT_PROC);
+
+       current->flags &= ~PF_FREEZER_SKIP;
+
+       /* move initrd to rootfs' /old */
+       sys_mount("..", ".", NULL, MS_MOVE, NULL);
+       /* switch root and cwd back to / of rootfs */
+       sys_chroot("..");
+
+       if (new_decode_dev(real_root_dev) == Root_RAM0) {
+               sys_chdir("/old");
+               return;
+       }
+
+       sys_chdir("/");
+       ROOT_DEV = new_decode_dev(real_root_dev);
+       mount_root();
+
+       printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
+       error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
+       if (!error)
+               printk("okay\n");
+       else {
+               int fd = sys_open("/dev/root.old", O_RDWR, 0);
+               if (error == -ENOENT)
+                       printk("/initrd does not exist. Ignored.\n");
+               else
+                       printk("failed\n");
+               printk(KERN_NOTICE "Unmounting old root\n");
+               sys_umount("/old", MNT_DETACH);
+               printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
+               if (fd < 0) {
+                       error = fd;
+               } else {
+                       error = sys_ioctl(fd, BLKFLSBUF, 0);
+                       sys_close(fd);
+               }
+               printk(!error ? "okay\n" : "failed\n");
+       }
+}
+
+int __init initrd_load(void)
+{
+       if (mount_initrd) {
+               create_dev("/dev/ram", Root_RAM0);
+               /*
+                * Load the initrd data into /dev/ram0. Execute it as initrd
+                * unless /dev/ram0 is supposed to be our actual root device,
+                * in that case the ram disk is just set up here, and gets
+                * mounted in the normal path.
+                */
+               if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
+                       sys_unlink("/initrd.image");
+                       handle_initrd();
+                       return 1;
+               }
+       }
+       sys_unlink("/initrd.image");
+       return 0;
+}