init/do_mounts_initrd.c

   1 #define __KERNEL_SYSCALLS__
   2 #include <linux/unistd.h>
   3 #include <linux/kernel.h>
   4 #include <linux/fs.h>
   5 #include <linux/minix_fs.h>
   6 #include <linux/ext2_fs.h>
   7 #include <linux/romfs_fs.h>
   8 #include <linux/initrd.h>
   9 #include <linux/sched.h>
  10
  11 #include "do_mounts.h"
  12
  13 unsigned long initrd_start, initrd_end;
  14 int initrd_below_start_ok;
  15 unsigned int real_root_dev;     /* do_proc_dointvec cannot handle kdev_t */
  16 static int __initdata old_fd, root_fd;
  17 static int __initdata mount_initrd = 1;
  18
  19 static int __init no_initrd(char *str)
  20 {
  21         mount_initrd = 0;
  22         return 1;
  23 }
  24
  25 __setup("noinitrd", no_initrd);
  26
  27 static int __init do_linuxrc(void * shell)
  28 {
  29         static char *argv[] = { "linuxrc", NULL, };
  30         extern char * envp_init[];
  31
  32         sys_close(old_fd);sys_close(root_fd);
  33         sys_close(0);sys_close(1);sys_close(2);
  34         sys_setsid();
  35         (void) sys_open("/dev/console",O_RDWR,0);
  36         (void) sys_dup(0);
  37         (void) sys_dup(0);
  38         return execve(shell, argv, envp_init);
  39 }
  40
  41 static void __init handle_initrd(void)
  42 {
  43         int error;
  44         int pid;
  45
  46         real_root_dev = new_encode_dev(ROOT_DEV);
  47         create_dev("/dev/root.old", Root_RAM0, NULL);
  48         /* mount initrd on rootfs' /root */
  49         mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
  50         sys_mkdir("/old", 0700);
  51         root_fd = sys_open("/", 0, 0);
  52         old_fd = sys_open("/old", 0, 0);
  53         /* move initrd over / and chdir/chroot in initrd root */
  54         sys_chdir("/root");
  55         sys_mount(".", "/", NULL, MS_MOVE, NULL);
  56         sys_chroot(".");
  57         mount_devfs_fs ();
  58
  59         pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
  60         if (pid > 0) {
  61                 while (pid != sys_wait4(-1, NULL, 0, NULL))
  62                         yield();
  63         }
  64
  65         /* move initrd to rootfs' /old */
  66         sys_fchdir(old_fd);
  67         sys_mount("/", ".", NULL, MS_MOVE, NULL);
  68         /* switch root and cwd back to / of rootfs */
  69         sys_fchdir(root_fd);
  70         sys_chroot(".");
  71         sys_close(old_fd);
  72         sys_close(root_fd);
  73         umount_devfs("/old/dev");
  74
  75         if (new_decode_dev(real_root_dev) == Root_RAM0) {
  76                 sys_chdir("/old");
  77                 return;
  78         }
  79
  80         ROOT_DEV = new_decode_dev(real_root_dev);
  81         mount_root();
  82
  83         printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
  84         error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
  85         if (!error)
  86                 printk("okay\n");
  87         else {
  88                 int fd = sys_open("/dev/root.old", O_RDWR, 0);
  89                 if (error == -ENOENT)
  90                         printk("/initrd does not exist. Ignored.\n");
  91                 else
  92                         printk("failed\n");
  93                 printk(KERN_NOTICE "Unmounting old root\n");
  94                 sys_umount("/old", MNT_DETACH);
  95                 printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
  96                 if (fd < 0) {
  97                         error = fd;
  98                 } else {
  99                         error = sys_ioctl(fd, BLKFLSBUF, 0);
 100                         sys_close(fd);
 101                 }
 102                 printk(!error ? "okay\n" : "failed\n");
 103         }
 104 }
 105
 106 int __init initrd_load(void)
 107 {
 108         if (mount_initrd) {
 109                 create_dev("/dev/ram", Root_RAM0, NULL);
 110                 /*
 111                  * Load the initrd data into /dev/ram0. Execute it as initrd
 112                  * unless /dev/ram0 is supposed to be our actual root device,
 113                  * in that case the ram disk is just set up here, and gets
 114                  * mounted in the normal path.
 115                  */
 116                 if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
 117                         sys_unlink("/initrd.image");
 118                         handle_initrd();
 119                         return 1;
 120                 }
 121         }
 122         sys_unlink("/initrd.image");
 123         return 0;
 124 }