LXR linux/init/do_mounts

   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#include <linux/freezer.h>
  10
  11#include "do_mounts.h"
  12
  13unsigned long initrd_start, initrd_end;
  14int initrd_below_start_ok;
  15unsigned int real_root_dev;     /* do_proc_dointvec cannot handle kdev_t */
  16static int __initdata old_fd, root_fd;
  17static int __initdata mount_initrd = 1;
  18
  19static int __init no_initrd(char *str)
  20{
  21        mount_initrd = 0;
  22        return 1;
  23}
  24
  25__setup("noinitrd", no_initrd);
  26
  27static 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 kernel_execve(shell, argv, envp_init);
  39}
  40
  41static 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);
  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
  58        /*
  59         * In case that a resume from disk is carried out by linuxrc or one of
  60         * its children, we need to tell the freezer not to wait for us.
  61         */
  62        current->flags |= PF_FREEZER_SKIP;
  63
  64        pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
  65        if (pid > 0)
  66                while (pid != sys_wait4(-1, NULL, 0, NULL))
  67                        yield();
  68
  69        current->flags &= ~PF_FREEZER_SKIP;
  70
  71        /* move initrd to rootfs' /old */
  72        sys_fchdir(old_fd);
  73        sys_mount("/", ".", NULL, MS_MOVE, NULL);
  74        /* switch root and cwd back to / of rootfs */
  75        sys_fchdir(root_fd);
  76        sys_chroot(".");
  77        sys_close(old_fd);
  78        sys_close(root_fd);
  79
  80        if (new_decode_dev(real_root_dev) == Root_RAM0) {
  81                sys_chdir("/old");
  82                return;
  83        }
  84
  85        ROOT_DEV = new_decode_dev(real_root_dev);
  86        mount_root();
  87
  88        printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
  89        error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
  90        if (!error)
  91                printk("okay\n");
  92        else {
  93                int fd = sys_open("/dev/root.old", O_RDWR, 0);
  94                if (error == -ENOENT)
  95                        printk("/initrd does not exist. Ignored.\n");
  96                else
  97                        printk("failed\n");
  98                printk(KERN_NOTICE "Unmounting old root\n");
  99                sys_umount("/old", MNT_DETACH);
 100                printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
 101                if (fd < 0) {
 102                        error = fd;
 103                } else {
 104                        error = sys_ioctl(fd, BLKFLSBUF, 0);
 105                        sys_close(fd);
 106                }
 107                printk(!error ? "okay\n" : "failed\n");
 108        }
 109}
 110
 111int __init initrd_load(void)
 112{
 113        if (mount_initrd) {
 114                create_dev("/dev/ram", Root_RAM0);
 115                /*
 116                 * Load the initrd data into /dev/ram0. Execute it as initrd
 117                 * unless /dev/ram0 is supposed to be our actual root device,
 118                 * in that case the ram disk is just set up here, and gets
 119                 * mounted in the normal path.
 120                 */
 121                if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
 122                        sys_unlink("/initrd.image");
 123                        handle_initrd();
 124                        return 1;
 125                }
 126        }
 127        sys_unlink("/initrd.image");
 128        return 0;
 129}
 130