Root/init/do_mounts_initrd.c

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#include <linux/kmod.h>
20
21#include "do_mounts.h"
22
23unsigned long initrd_start, initrd_end;
24int initrd_below_start_ok;
25unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
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_linuxrc(struct subprocess_info *info, struct cred *new)
37{
38    sys_unshare(CLONE_FS | CLONE_FILES);
39    /* stdin/stdout/stderr for /linuxrc */
40    sys_open("/dev/console", O_RDWR, 0);
41    sys_dup(0);
42    sys_dup(0);
43    /* move initrd over / and chdir/chroot in initrd root */
44    sys_chdir("/root");
45    sys_mount(".", "/", NULL, MS_MOVE, NULL);
46    sys_chroot(".");
47    sys_setsid();
48    return 0;
49}
50
51static void __init handle_initrd(void)
52{
53    struct subprocess_info *info;
54    static char *argv[] = { "linuxrc", NULL, };
55    extern char *envp_init[];
56    int error;
57
58    real_root_dev = new_encode_dev(ROOT_DEV);
59    create_dev("/dev/root.old", Root_RAM0);
60    /* mount initrd on rootfs' /root */
61    mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
62    sys_mkdir("/old", 0700);
63    sys_chdir("/old");
64
65    /* try loading default modules from initrd */
66    load_default_modules();
67
68    /*
69     * In case that a resume from disk is carried out by linuxrc or one of
70     * its children, we need to tell the freezer not to wait for us.
71     */
72    current->flags |= PF_FREEZER_SKIP;
73
74    info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
75                     GFP_KERNEL, init_linuxrc, NULL, NULL);
76    if (!info)
77        return;
78    call_usermodehelper_exec(info, UMH_WAIT_PROC);
79
80    current->flags &= ~PF_FREEZER_SKIP;
81
82    /* move initrd to rootfs' /old */
83    sys_mount("..", ".", NULL, MS_MOVE, NULL);
84    /* switch root and cwd back to / of rootfs */
85    sys_chroot("..");
86
87    if (new_decode_dev(real_root_dev) == Root_RAM0) {
88        sys_chdir("/old");
89        return;
90    }
91
92    sys_chdir("/");
93    ROOT_DEV = new_decode_dev(real_root_dev);
94    mount_root();
95
96    printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
97    error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
98    if (!error)
99        printk("okay\n");
100    else {
101        int fd = sys_open("/dev/root.old", O_RDWR, 0);
102        if (error == -ENOENT)
103            printk("/initrd does not exist. Ignored.\n");
104        else
105            printk("failed\n");
106        printk(KERN_NOTICE "Unmounting old root\n");
107        sys_umount("/old", MNT_DETACH);
108        printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
109        if (fd < 0) {
110            error = fd;
111        } else {
112            error = sys_ioctl(fd, BLKFLSBUF, 0);
113            sys_close(fd);
114        }
115        printk(!error ? "okay\n" : "failed\n");
116    }
117}
118
119int __init initrd_load(void)
120{
121    if (mount_initrd) {
122        create_dev("/dev/ram", Root_RAM0);
123        /*
124         * Load the initrd data into /dev/ram0. Execute it as initrd
125         * unless /dev/ram0 is supposed to be our actual root device,
126         * in that case the ram disk is just set up here, and gets
127         * mounted in the normal path.
128         */
129        if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
130            sys_unlink("/initrd.image");
131            handle_initrd();
132            return 1;
133        }
134    }
135    sys_unlink("/initrd.image");
136    return 0;
137}
138

Archive Download this file



interactive