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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/unistd.h>
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/minix_fs.h>
- #include <linux/romfs_fs.h>
- #include <linux/initrd.h>
- #include <linux/sched.h>
- #include <linux/freezer.h>
- #include <linux/kmod.h>
- #include <uapi/linux/mount.h>
- #include "do_mounts.h"
- unsigned long initrd_start, initrd_end;
- int initrd_below_start_ok;
- static unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
- static int __initdata mount_initrd = 1;
- phys_addr_t phys_initrd_start __initdata;
- unsigned long phys_initrd_size __initdata;
- #ifdef CONFIG_SYSCTL
- static struct ctl_table kern_do_mounts_initrd_table[] = {
- {
- .procname = "real-root-dev",
- .data = &real_root_dev,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec,
- },
- { }
- };
- static __init int kernel_do_mounts_initrd_sysctls_init(void)
- {
- register_sysctl_init("kernel", kern_do_mounts_initrd_table);
- return 0;
- }
- late_initcall(kernel_do_mounts_initrd_sysctls_init);
- #endif /* CONFIG_SYSCTL */
- static int __init no_initrd(char *str)
- {
- mount_initrd = 0;
- return 1;
- }
- __setup("noinitrd", no_initrd);
- static int __init early_initrdmem(char *p)
- {
- phys_addr_t start;
- unsigned long size;
- char *endp;
- start = memparse(p, &endp);
- if (*endp == ',') {
- size = memparse(endp + 1, NULL);
- phys_initrd_start = start;
- phys_initrd_size = size;
- }
- return 0;
- }
- early_param("initrdmem", early_initrdmem);
- static int __init early_initrd(char *p)
- {
- return early_initrdmem(p);
- }
- early_param("initrd", early_initrd);
- static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)
- {
- ksys_unshare(CLONE_FS | CLONE_FILES);
- console_on_rootfs();
- /* move initrd over / and chdir/chroot in initrd root */
- init_chdir("/root");
- init_mount(".", "/", NULL, MS_MOVE, NULL);
- init_chroot(".");
- ksys_setsid();
- return 0;
- }
- static void __init handle_initrd(void)
- {
- struct subprocess_info *info;
- static char *argv[] = { "linuxrc", NULL, };
- extern char *envp_init[];
- int error;
- pr_warn("using deprecated initrd support, will be removed in 2021.\n");
- real_root_dev = new_encode_dev(ROOT_DEV);
- create_dev("/dev/root.old", Root_RAM0);
- /* mount initrd on rootfs' /root */
- mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
- init_mkdir("/old", 0700);
- init_chdir("/old");
- info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
- GFP_KERNEL, init_linuxrc, NULL, NULL);
- if (!info)
- return;
- call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE);
- /* move initrd to rootfs' /old */
- init_mount("..", ".", NULL, MS_MOVE, NULL);
- /* switch root and cwd back to / of rootfs */
- init_chroot("..");
- if (new_decode_dev(real_root_dev) == Root_RAM0) {
- init_chdir("/old");
- return;
- }
- init_chdir("/");
- ROOT_DEV = new_decode_dev(real_root_dev);
- mount_root();
- printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
- error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
- if (!error)
- printk("okay\n");
- else {
- if (error == -ENOENT)
- printk("/initrd does not exist. Ignored.\n");
- else
- printk("failed\n");
- printk(KERN_NOTICE "Unmounting old root\n");
- init_umount("/old", MNT_DETACH);
- }
- }
- bool __init initrd_load(void)
- {
- if (mount_initrd) {
- create_dev("/dev/ram", Root_RAM0);
- /*
- * Load the initrd data into /dev/ram0. Execute it as initrd
- * unless /dev/ram0 is supposed to be our actual root device,
- * in that case the ram disk is just set up here, and gets
- * mounted in the normal path.
- */
- if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
- init_unlink("/initrd.image");
- handle_initrd();
- return true;
- }
- }
- init_unlink("/initrd.image");
- return false;
- }
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