1 files changed, 154 insertions, 0 deletions
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
new file mode 100644
index 000000000..347312413
--- /dev/null
+++ b/init/do_mounts_initrd.c
@@ -0,0 +1,154 @@
+// 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;
+}