mirror of https://gitee.com/openkylin/linux.git
155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/unistd.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/minix_fs.h>
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#include <linux/romfs_fs.h>
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#include <linux/initrd.h>
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#include <linux/sched.h>
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#include <linux/freezer.h>
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#include <linux/kmod.h>
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#include <uapi/linux/mount.h>
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#include "do_mounts.h"
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unsigned long initrd_start, initrd_end;
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int initrd_below_start_ok;
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unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
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static int __initdata mount_initrd = 1;
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phys_addr_t phys_initrd_start __initdata;
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unsigned long phys_initrd_size __initdata;
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static int __init no_initrd(char *str)
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{
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mount_initrd = 0;
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return 1;
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}
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__setup("noinitrd", no_initrd);
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static int __init early_initrdmem(char *p)
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{
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phys_addr_t start;
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unsigned long size;
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char *endp;
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start = memparse(p, &endp);
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if (*endp == ',') {
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size = memparse(endp + 1, NULL);
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phys_initrd_start = start;
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phys_initrd_size = size;
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}
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return 0;
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}
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early_param("initrdmem", early_initrdmem);
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/*
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* This is here as the initrd keyword has been in use since 11/2018
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* on ARM, PowerPC, and MIPS.
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* It should not be; it is reserved for bootloaders.
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*/
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static int __init early_initrd(char *p)
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{
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return early_initrdmem(p);
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}
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early_param("initrd", early_initrd);
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static int init_linuxrc(struct subprocess_info *info, struct cred *new)
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{
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ksys_unshare(CLONE_FS | CLONE_FILES);
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console_on_rootfs();
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/* move initrd over / and chdir/chroot in initrd root */
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ksys_chdir("/root");
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do_mount(".", "/", NULL, MS_MOVE, NULL);
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ksys_chroot(".");
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ksys_setsid();
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return 0;
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}
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static void __init handle_initrd(void)
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{
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struct subprocess_info *info;
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static char *argv[] = { "linuxrc", NULL, };
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extern char *envp_init[];
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int error;
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real_root_dev = new_encode_dev(ROOT_DEV);
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create_dev("/dev/root.old", Root_RAM0);
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/* mount initrd on rootfs' /root */
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mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
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ksys_mkdir("/old", 0700);
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ksys_chdir("/old");
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/*
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* In case that a resume from disk is carried out by linuxrc or one of
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* its children, we need to tell the freezer not to wait for us.
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*/
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current->flags |= PF_FREEZER_SKIP;
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info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
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GFP_KERNEL, init_linuxrc, NULL, NULL);
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if (!info)
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return;
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call_usermodehelper_exec(info, UMH_WAIT_PROC);
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current->flags &= ~PF_FREEZER_SKIP;
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/* move initrd to rootfs' /old */
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do_mount("..", ".", NULL, MS_MOVE, NULL);
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/* switch root and cwd back to / of rootfs */
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ksys_chroot("..");
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if (new_decode_dev(real_root_dev) == Root_RAM0) {
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ksys_chdir("/old");
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return;
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}
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ksys_chdir("/");
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ROOT_DEV = new_decode_dev(real_root_dev);
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mount_root();
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printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
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error = do_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
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if (!error)
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printk("okay\n");
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else {
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int fd = ksys_open("/dev/root.old", O_RDWR, 0);
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if (error == -ENOENT)
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printk("/initrd does not exist. Ignored.\n");
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else
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printk("failed\n");
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printk(KERN_NOTICE "Unmounting old root\n");
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ksys_umount("/old", MNT_DETACH);
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printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
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if (fd < 0) {
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error = fd;
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} else {
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error = ksys_ioctl(fd, BLKFLSBUF, 0);
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ksys_close(fd);
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}
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printk(!error ? "okay\n" : "failed\n");
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}
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}
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bool __init initrd_load(void)
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{
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if (mount_initrd) {
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create_dev("/dev/ram", Root_RAM0);
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/*
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* Load the initrd data into /dev/ram0. Execute it as initrd
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* unless /dev/ram0 is supposed to be our actual root device,
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* in that case the ram disk is just set up here, and gets
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* mounted in the normal path.
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*/
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if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
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ksys_unlink("/initrd.image");
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handle_initrd();
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return true;
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}
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}
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ksys_unlink("/initrd.image");
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return false;
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}
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