1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Many of the syscalls used in this file expect some of the arguments 4 * to be __user pointers not __kernel pointers. To limit the sparse 5 * noise, turn off sparse checking for this file. 6 */ 7 #ifdef __CHECKER__ 8 #undef __CHECKER__ 9 #warning "Sparse checking disabled for this file" 10 #endif 11 12 #include <linux/unistd.h> 13 #include <linux/kernel.h> 14 #include <linux/fs.h> 15 #include <linux/minix_fs.h> 16 #include <linux/romfs_fs.h> 17 #include <linux/initrd.h> 18 #include <linux/sched.h> 19 #include <linux/freezer.h> 20 #include <linux/kmod.h> 21 22 #include "do_mounts.h" 23 24 unsigned long initrd_start, initrd_end; 25 int initrd_below_start_ok; 26 unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */ 27 static int __initdata mount_initrd = 1; 28 29 static int __init no_initrd(char *str) 30 { 31 mount_initrd = 0; 32 return 1; 33 } 34 35 __setup("noinitrd", no_initrd); 36 37 static int init_linuxrc(struct subprocess_info *info, struct cred *new) 38 { 39 ksys_unshare(CLONE_FS | CLONE_FILES); 40 /* stdin/stdout/stderr for /linuxrc */ 41 ksys_open("/dev/console", O_RDWR, 0); 42 ksys_dup(0); 43 ksys_dup(0); 44 /* move initrd over / and chdir/chroot in initrd root */ 45 ksys_chdir("/root"); 46 ksys_mount(".", "/", NULL, MS_MOVE, NULL); 47 ksys_chroot("."); 48 ksys_setsid(); 49 return 0; 50 } 51 52 static void __init handle_initrd(void) 53 { 54 struct subprocess_info *info; 55 static char *argv[] = { "linuxrc", NULL, }; 56 extern char *envp_init[]; 57 int error; 58 59 real_root_dev = new_encode_dev(ROOT_DEV); 60 create_dev("/dev/root.old", Root_RAM0); 61 /* mount initrd on rootfs' /root */ 62 mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); 63 ksys_mkdir("/old", 0700); 64 ksys_chdir("/old"); 65 66 /* try loading default modules from initrd */ 67 load_default_modules(); 68 69 /* 70 * In case that a resume from disk is carried out by linuxrc or one of 71 * its children, we need to tell the freezer not to wait for us. 72 */ 73 current->flags |= PF_FREEZER_SKIP; 74 75 info = call_usermodehelper_setup("/linuxrc", argv, envp_init, 76 GFP_KERNEL, init_linuxrc, NULL, NULL); 77 if (!info) 78 return; 79 call_usermodehelper_exec(info, UMH_WAIT_PROC); 80 81 current->flags &= ~PF_FREEZER_SKIP; 82 83 /* move initrd to rootfs' /old */ 84 ksys_mount("..", ".", NULL, MS_MOVE, NULL); 85 /* switch root and cwd back to / of rootfs */ 86 ksys_chroot(".."); 87 88 if (new_decode_dev(real_root_dev) == Root_RAM0) { 89 ksys_chdir("/old"); 90 return; 91 } 92 93 ksys_chdir("/"); 94 ROOT_DEV = new_decode_dev(real_root_dev); 95 mount_root(); 96 97 printk(KERN_NOTICE "Trying to move old root to /initrd ... "); 98 error = ksys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL); 99 if (!error) 100 printk("okay\n"); 101 else { 102 int fd = ksys_open("/dev/root.old", O_RDWR, 0); 103 if (error == -ENOENT) 104 printk("/initrd does not exist. Ignored.\n"); 105 else 106 printk("failed\n"); 107 printk(KERN_NOTICE "Unmounting old root\n"); 108 ksys_umount("/old", MNT_DETACH); 109 printk(KERN_NOTICE "Trying to free ramdisk memory ... "); 110 if (fd < 0) { 111 error = fd; 112 } else { 113 error = ksys_ioctl(fd, BLKFLSBUF, 0); 114 ksys_close(fd); 115 } 116 printk(!error ? "okay\n" : "failed\n"); 117 } 118 } 119 120 bool __init initrd_load(void) 121 { 122 if (mount_initrd) { 123 create_dev("/dev/ram", Root_RAM0); 124 /* 125 * Load the initrd data into /dev/ram0. Execute it as initrd 126 * unless /dev/ram0 is supposed to be our actual root device, 127 * in that case the ram disk is just set up here, and gets 128 * mounted in the normal path. 129 */ 130 if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) { 131 ksys_unlink("/initrd.image"); 132 handle_initrd(); 133 return true; 134 } 135 } 136 ksys_unlink("/initrd.image"); 137 return false; 138 } 139