init/do_mounts_initrd.c

   1
   2 #include <linux/kernel.h>
   3 #include <linux/fs.h>
   4 #include <linux/minix_fs.h>
   5 #include <linux/ext2_fs.h>
   6 #include <linux/romfs_fs.h>
   7 #include <linux/initrd.h>
   8
   9 #include "do_mounts.h"
  10
  11 unsigned int real_root_dev;     /* do_proc_dointvec cannot handle kdev_t */
  12 static int __initdata old_fd, root_fd;
  13 static int __initdata mount_initrd = 1;
  14
  15 static int __init no_initrd(char *str)
  16 {
  17         mount_initrd = 0;
  18         return 1;
  19 }
  20
  21 __setup("noinitrd", no_initrd);
  22
  23 static int __init do_linuxrc(void * shell)
  24 {
  25         static char *argv[] = { "linuxrc", NULL, };
  26         extern char * envp_init[];
  27
  28         close(old_fd);close(root_fd);
  29         close(0);close(1);close(2);
  30         setsid();
  31         (void) open("/dev/console",O_RDWR,0);
  32         (void) dup(0);
  33         (void) dup(0);
  34         return execve(shell, argv, envp_init);
  35 }
  36
  37 static void __init handle_initrd(void)
  38 {
  39         int error;
  40         int i, pid;
  41
  42         real_root_dev = ROOT_DEV;
  43         create_dev("/dev/root.old", Root_RAM0, NULL);
  44         /* mount initrd on rootfs' /root */
  45         mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
  46         sys_mkdir("/old", 0700);
  47         root_fd = open("/", 0, 0);
  48         old_fd = open("/old", 0, 0);
  49         /* move initrd over / and chdir/chroot in initrd root */
  50         sys_chdir("/root");
  51         sys_mount(".", "/", NULL, MS_MOVE, NULL);
  52         sys_chroot(".");
  53         mount_devfs_fs ();
  54
  55         pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
  56         if (pid > 0) {
  57                 while (pid != waitpid(-1, &i, 0))
  58                         yield();
  59         }
  60
  61         /* move initrd to rootfs' /old */
  62         sys_fchdir(old_fd);
  63         sys_mount("/", ".", NULL, MS_MOVE, NULL);
  64         /* switch root and cwd back to / of rootfs */
  65         sys_fchdir(root_fd);
  66         sys_chroot(".");
  67         close(old_fd);
  68         close(root_fd);
  69         umount_devfs("/old/dev");
  70
  71         if (real_root_dev == Root_RAM0) {
  72                 sys_chdir("/old");
  73                 return;
  74         }
  75
  76         ROOT_DEV = real_root_dev;
  77         mount_root();
  78
  79         printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
  80         error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
  81         if (!error)
  82                 printk("okay\n");
  83         else {
  84                 int fd = open("/dev/root.old", O_RDWR, 0);
  85                 printk("failed\n");
  86                 printk(KERN_NOTICE "Unmounting old root\n");
  87                 sys_umount("/old", MNT_DETACH);
  88                 printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
  89                 if (fd < 0) {
  90                         error = fd;
  91                 } else {
  92                         error = sys_ioctl(fd, BLKFLSBUF, 0);
  93                         close(fd);
  94                 }
  95                 printk(!error ? "okay\n" : "failed\n");
  96         }
  97 }
  98
  99 int __init initrd_load(void)
 100 {
 101         if (!mount_initrd)
 102                 return 0;
 103
 104         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, 0), NULL);
 105         create_dev("/dev/initrd", MKDEV(RAMDISK_MAJOR, INITRD_MINOR), NULL);
 106         /* Load the initrd data into /dev/ram0. Execute it as initrd unless
 107          * /dev/ram0 is supposed to be our actual root device, in
 108          * that case the ram disk is just set up here, and gets
 109          * mounted in the normal path. */
 110         if (rd_load_image("/dev/initrd") && ROOT_DEV != Root_RAM0) {
 111                 handle_initrd();
 112                 return 1;
 113         }
 114         return 0;
 115 }