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

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