linux/init/do_mounts_initrd.c
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   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 const char *argv[] = { "linuxrc", NULL, };
  30        extern const char *envp_init[];
  31        const char *shell = _shell;
  32
  33        sys_close(old_fd);sys_close(root_fd);
  34        sys_setsid();
  35        return kernel_execve(shell, argv, envp_init);
  36}
  37
  38static void __init handle_initrd(void)
  39{
  40        int error;
  41        int pid;
  42
  43        real_root_dev = new_encode_dev(ROOT_DEV);
  44        create_dev("/dev/root.old", Root_RAM0);
  45        /* mount initrd on rootfs' /root */
  46        mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
  47        sys_mkdir("/old", 0700);
  48        root_fd = sys_open("/", 0, 0);
  49        old_fd = sys_open("/old", 0, 0);
  50        /* move initrd over / and chdir/chroot in initrd root */
  51        sys_chdir("/root");
  52        sys_mount(".", "/", NULL, MS_MOVE, NULL);
  53        sys_chroot(".");
  54
  55        /*
  56         * In case that a resume from disk is carried out by linuxrc or one of
  57         * its children, we need to tell the freezer not to wait for us.
  58         */
  59        current->flags |= PF_FREEZER_SKIP;
  60
  61        pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
  62        if (pid > 0)
  63                while (pid != sys_wait4(-1, NULL, 0, NULL))
  64                        yield();
  65
  66        current->flags &= ~PF_FREEZER_SKIP;
  67
  68        /* move initrd to rootfs' /old */
  69        sys_fchdir(old_fd);
  70        sys_mount("/", ".", NULL, MS_MOVE, NULL);
  71        /* switch root and cwd back to / of rootfs */
  72        sys_fchdir(root_fd);
  73        sys_chroot(".");
  74        sys_close(old_fd);
  75        sys_close(root_fd);
  76
  77        if (new_decode_dev(real_root_dev) == Root_RAM0) {
  78                sys_chdir("/old");
  79                return;
  80        }
  81
  82        ROOT_DEV = new_decode_dev(real_root_dev);
  83        mount_root();
  84
  85        printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
  86        error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
  87        if (!error)
  88                printk("okay\n");
  89        else {
  90                int fd = sys_open("/dev/root.old", O_RDWR, 0);
  91                if (error == -ENOENT)
  92                        printk("/initrd does not exist. Ignored.\n");
  93                else
  94                        printk("failed\n");
  95                printk(KERN_NOTICE "Unmounting old root\n");
  96                sys_umount("/old", MNT_DETACH);
  97                printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
  98                if (fd < 0) {
  99                        error = fd;
 100                } else {
 101                        error = sys_ioctl(fd, BLKFLSBUF, 0);
 102                        sys_close(fd);
 103                }
 104                printk(!error ? "okay\n" : "failed\n");
 105        }
 106}
 107
 108int __init initrd_load(void)
 109{
 110        if (mount_initrd) {
 111                create_dev("/dev/ram", Root_RAM0);
 112                /*
 113                 * Load the initrd data into /dev/ram0. Execute it as initrd
 114                 * unless /dev/ram0 is supposed to be our actual root device,
 115                 * in that case the ram disk is just set up here, and gets
 116                 * mounted in the normal path.
 117                 */
 118                if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
 119                        sys_unlink("/initrd.image");
 120                        handle_initrd();
 121                        return 1;
 122                }
 123        }
 124        sys_unlink("/initrd.image");
 125        return 0;
 126}
 127
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