diff options
Diffstat (limited to 'init/do_mounts_initrd.c')
| -rw-r--r-- | init/do_mounts_initrd.c | 155 |
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; +} |