init/do_mounts_initrd.c

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