Root/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
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

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