From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 init/do_mounts_initrd.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 init/do_mounts_initrd.c

(limited to 'init/do_mounts_initrd.c')

diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
new file mode 100644
index 000000000..a49c59680
--- /dev/null
+++ b/init/do_mounts_initrd.c
@@ -0,0 +1,143 @@
+/*
+ * Many of the syscalls used in this file expect some of the arguments
+ * to be __user pointers not __kernel pointers.  To limit the sparse
+ * noise, turn off sparse checking for this file.
+ */
+#ifdef __CHECKER__
+#undef __CHECKER__
+#warning "Sparse checking disabled for this file"
+#endif
+
+#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/suspend.h>
+#include <linux/freezer.h>
+#include <linux/kmod.h>
+
+#include "do_mounts.h"
+
+unsigned long initrd_start, initrd_end;
+int initrd_below_start_ok;
+unsigned int real_root_dev;	/* do_proc_dointvec cannot handle kdev_t */
+static int __initdata mount_initrd = 1;
+
+static int __init no_initrd(char *str)
+{
+	mount_initrd = 0;
+	return 1;
+}
+
+__setup("noinitrd", no_initrd);
+
+static int init_linuxrc(struct subprocess_info *info, struct cred *new)
+{
+	sys_unshare(CLONE_FS | CLONE_FILES);
+	/* stdin/stdout/stderr for /linuxrc */
+	sys_open("/dev/console", O_RDWR, 0);
+	sys_dup(0);
+	sys_dup(0);
+	/* move initrd over / and chdir/chroot in initrd root */
+	sys_chdir("/root");
+	sys_mount(".", "/", NULL, MS_MOVE, NULL);
+	sys_chroot(".");
+	sys_setsid();
+	return 0;
+}
+
+static void __init handle_initrd(void)
+{
+	struct subprocess_info *info;
+	static char *argv[] = { "linuxrc", NULL, };
+	extern char *envp_init[];
+	int error;
+
+	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);
+	sys_mkdir("/old", 0700);
+	sys_chdir("/old");
+
+	/* try loading default modules from initrd */
+	load_default_modules();
+
+	/*
+	 * In case that a resume from disk is carried out by linuxrc or one of
+	 * its children, we need to tell the freezer not to wait for us.
+	 */
+	current->flags |= PF_FREEZER_SKIP;
+
+	info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
+					 GFP_KERNEL, init_linuxrc, NULL, NULL);
+	if (!info)
+		return;
+	call_usermodehelper_exec(info, UMH_WAIT_PROC);
+
+	current->flags &= ~PF_FREEZER_SKIP;
+
+	if (!resume_attempted)
+		printk(KERN_ERR "TuxOnIce: No attempt was made to resume from "
+				"any image that might exist.\n");
+	clear_toi_state(TOI_BOOT_TIME);
+
+	/* move initrd to rootfs' /old */
+	sys_mount("..", ".", NULL, MS_MOVE, NULL);
+	/* switch root and cwd back to / of rootfs */
+	sys_chroot("..");
+
+	if (new_decode_dev(real_root_dev) == Root_RAM0) {
+		sys_chdir("/old");
+		return;
+	}
+
+	sys_chdir("/");
+	ROOT_DEV = new_decode_dev(real_root_dev);
+	mount_root();
+
+	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
+	error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
+	if (!error)
+		printk("okay\n");
+	else {
+		int fd = sys_open("/dev/root.old", O_RDWR, 0);
+		if (error == -ENOENT)
+			printk("/initrd does not exist. Ignored.\n");
+		else
+			printk("failed\n");
+		printk(KERN_NOTICE "Unmounting old root\n");
+		sys_umount("/old", MNT_DETACH);
+		printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
+		if (fd < 0) {
+			error = fd;
+		} else {
+			error = sys_ioctl(fd, BLKFLSBUF, 0);
+			sys_close(fd);
+		}
+		printk(!error ? "okay\n" : "failed\n");
+	}
+}
+
+int __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) {
+			sys_unlink("/initrd.image");
+			handle_initrd();
+			return 1;
+		}
+	}
+	sys_unlink("/initrd.image");
+	return 0;
+}
-- 
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