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-rw-r--r--init/do_mounts_initrd.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
new file mode 100644
index 0000000000..425f4bcf4b
--- /dev/null
+++ b/init/do_mounts_initrd.c
@@ -0,0 +1,155 @@
+// 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(char *root_device_name)
+{
+ 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_root_generic("/dev/root.old", root_device_name,
+ 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(root_device_name);
+
+ 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(char *root_device_name)
+{
+ 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(root_device_name);
+ return true;
+ }
+ }
+ init_unlink("/initrd.image");
+ return false;
+}