linux/init/do_mounts_initrd.c
<<
>>
Prefs
   1/*
   2 * Many of the syscalls used in this file expect some of the arguments
   3 * to be __user pointers not __kernel pointers.  To limit the sparse
   4 * noise, turn off sparse checking for this file.
   5 */
   6#ifdef __CHECKER__
   7#undef __CHECKER__
   8#warning "Sparse checking disabled for this file"
   9#endif
  10
  11#include <linux/unistd.h>
  12#include <linux/kernel.h>
  13#include <linux/fs.h>
  14#include <linux/minix_fs.h>
  15#include <linux/romfs_fs.h>
  16#include <linux/initrd.h>
  17#include <linux/sched.h>
  18#include <linux/freezer.h>
  19
  20#include "do_mounts.h"
  21
  22unsigned long initrd_start, initrd_end;
  23int initrd_below_start_ok;
  24unsigned int real_root_dev;     /* do_proc_dointvec cannot handle kdev_t */
  25static int __initdata old_fd, root_fd;
  26static int __initdata mount_initrd = 1;
  27
  28static int __init no_initrd(char *str)
  29{
  30        mount_initrd = 0;
  31        return 1;
  32}
  33
  34__setup("noinitrd", no_initrd);
  35
  36static int __init do_linuxrc(void *_shell)
  37{
  38        static const char *argv[] = { "linuxrc", NULL, };
  39        extern const char *envp_init[];
  40        const char *shell = _shell;
  41
  42        sys_close(old_fd);sys_close(root_fd);
  43        sys_setsid();
  44        return kernel_execve(shell, argv, envp_init);
  45}
  46
  47static void __init handle_initrd(void)
  48{
  49        int error;
  50        int pid;
  51
  52        real_root_dev = new_encode_dev(ROOT_DEV);
  53        create_dev("/dev/root.old", Root_RAM0);
  54        /* mount initrd on rootfs' /root */
  55        mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
  56        sys_mkdir("/old", 0700);
  57        root_fd = sys_open("/", 0, 0);
  58        old_fd = sys_open("/old", 0, 0);
  59        /* move initrd over / and chdir/chroot in initrd root */
  60        sys_chdir("/root");
  61        sys_mount(".", "/", NULL, MS_MOVE, NULL);
  62        sys_chroot(".");
  63
  64        /*
  65         * In case that a resume from disk is carried out by linuxrc or one of
  66         * its children, we need to tell the freezer not to wait for us.
  67         */
  68        current->flags |= PF_FREEZER_SKIP;
  69
  70        pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
  71        if (pid > 0)
  72                while (pid != sys_wait4(-1, NULL, 0, NULL))
  73                        yield();
  74
  75        current->flags &= ~PF_FREEZER_SKIP;
  76
  77        /* move initrd to rootfs' /old */
  78        sys_fchdir(old_fd);
  79        sys_mount("/", ".", NULL, MS_MOVE, NULL);
  80        /* switch root and cwd back to / of rootfs */
  81        sys_fchdir(root_fd);
  82        sys_chroot(".");
  83        sys_close(old_fd);
  84        sys_close(root_fd);
  85
  86        if (new_decode_dev(real_root_dev) == Root_RAM0) {
  87                sys_chdir("/old");
  88                return;
  89        }
  90
  91        ROOT_DEV = new_decode_dev(real_root_dev);
  92        mount_root();
  93
  94        printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
  95        error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
  96        if (!error)
  97                printk("okay\n");
  98        else {
  99                int fd = sys_open("/dev/root.old", O_RDWR, 0);
 100                if (error == -ENOENT)
 101                        printk("/initrd does not exist. Ignored.\n");
 102                else
 103                        printk("failed\n");
 104                printk(KERN_NOTICE "Unmounting old root\n");
 105                sys_umount("/old", MNT_DETACH);
 106                printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
 107                if (fd < 0) {
 108                        error = fd;
 109                } else {
 110                        error = sys_ioctl(fd, BLKFLSBUF, 0);
 111                        sys_close(fd);
 112                }
 113                printk(!error ? "okay\n" : "failed\n");
 114        }
 115}
 116
 117int __init initrd_load(void)
 118{
 119        if (mount_initrd) {
 120                create_dev("/dev/ram", Root_RAM0);
 121                /*
 122                 * Load the initrd data into /dev/ram0. Execute it as initrd
 123                 * unless /dev/ram0 is supposed to be our actual root device,
 124                 * in that case the ram disk is just set up here, and gets
 125                 * mounted in the normal path.
 126                 */
 127                if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
 128                        sys_unlink("/initrd.image");
 129                        handle_initrd();
 130                        return 1;
 131                }
 132        }
 133        sys_unlink("/initrd.image");
 134        return 0;
 135}
 136
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.