init/initramfs: Add dump_initrd command line option

Add a dump_initrd option to allow dumping /initrd.image after successful unpack. Require BLK_DEV_RAM=y. Change-Id: I77a41867afa7b4a51604a5153792a49efbab6189 Signed-off-by: Jeffy Chen <[email protected]>
ayufan-rock64 · Dec 18, 2018 · ff12055 · ff12055
1 parent b41c3c7
commit ff12055
Showing 1 changed file with 15 additions and 0 deletions.
diff --git a/init/initramfs.c b/init/initramfs.c
@@ -525,6 +525,17 @@ static int __init retain_initrd_param(char *str)
 }
 __setup("retain_initrd", retain_initrd_param);
 
+static int __initdata do_dump_initrd;
+
+static int __init dump_initrd_param(char *str)
+{
+	if (*str)
+		return 0;
+	do_dump_initrd = 1;
+	return 1;
+}
+__setup("dump_initrd", dump_initrd_param);
+
 extern char __initramfs_start[];
 extern unsigned long __initramfs_size;
 #include <linux/initrd.h>
@@ -642,6 +653,9 @@ static int __init populate_rootfs(void)
 		err = unpack_to_rootfs((char *)initrd_start,
 			initrd_end - initrd_start);
 		if (!err) {
+			if (do_dump_initrd)
+				goto dump;
+
 			free_initrd();
 			goto done;
 		} else {
@@ -650,6 +664,7 @@ static int __init populate_rootfs(void)
 		}
 		printk(KERN_INFO "rootfs image is not initramfs (%s)"
 				"; looks like an initrd\n", err);
+	dump:
 		fd = sys_open("/initrd.image",
 			      O_WRONLY|O_CREAT, 0700);
 		if (fd >= 0) {