build: New makefiles and stdio example

Signed-off-by: Louis Solofrizzo <lsolofrizzo@online.net>

unikernel-demo/.gitignore

@@ -0,0 +1,3 @@
+*.cmd
+*.img
+*.o

unikernel-demo/Makefile

@@ -0,0 +1,17 @@
+all:
+	$(MAKE) -C ../../../whiterose/ UKL=$(CURDIR) bzImage
+
+../../disk.img:
+	qemu-img create ../../disk.img 0g
+	mkfs.ext2 ../../disk.img
+	mkdir tmp_mnt
+	sudo mount -o loop ../../disk.img tmp_mnt
+	sudo debootstrap --arch amd64 jessie tmp_mnt
+	sudo umount tmp_mnt
+	rmdir tmp_mnt
+
+qemu: ../../disk.img
+	qemu-system-x86_64 -enable-kvm -s -m 1G -nographic -cpu host\
+		-kernel ../../../whiterose/arch/x86/boot/bzImage\
+		-append "console=ttyS0 ukl quiet root=/dev/sda"\
+		-hda ../../disk.img

unikernel-demo/README.md

@@ -2,11 +2,34 @@
 
 ### setup
 
+##### Requirements
+- qemu
+- debootstrap
+
+##### Clone & Configure the kernel
 ```
-mkdir unikernel && cd unikernel
 git clone https://github.com/ne02ptzero/whiterose
-(cd whiterose && make defconfig)
+cd whiterose && make defconfig
+```
+
+It will apply the default of the linux kernel, with UKL support. If you're
+trying to run this on exotic hardware, now is a good time to change the
+configuration. As long as you keep `CONFIG_UKL_LINUX` to `true`, you should be
+fine.
+
+##### Clone && Running the examples
+```
 git clone https://github.com/jzck/unikernel-demo
 cd unikernel-demo
-make && make run
+```
+
+Each example come with a Makefile. For example, if you want to run the unistd
+example, simply do:
+```
+make -C fs1/unistd all qemu
+```
+
+Or stdio:
+```
+make -C fs1/stdio all qemu
 ```

unikernel-demo/fs1/Makefile

@@ -1,9 +0,0 @@
-export ukl-obj-m := main.o
-    
-all:
-	$(MAKE) -C ../../whiterose/ UKL=$(PWD) bzImage
-
-qemu:
-	qemu-system-x86_64 -enable-kvm -s -m 1G -nographic -cpu host\
-	       	-kernel ../whiterose/arch/x86/boot/bzImage\
-		-append "console=ttyS0 ukl quiet"\

unikernel-demo/fs1/stdio/Makefile

@@ -0,0 +1,3 @@
+export ukl-obj-m := main.o
+
+include ../../Makefile

unikernel-demo/fs1/stdio/main.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+
+#ifndef USERSPACE
+#define main ukl_main
+#endif
+
+int main(void) {
+    FILE        *f = fopen("/etc/passwd", "r");
+    ssize_t     ret;
+    char        buf[256] = { 0 };
+
+    if (f == NULL)
+    {
+        fputs("Cannot open /etc/passwd\n", stderr);
+        return 1;
+    }
+
+    while ((ret = fread(buf, 1, sizeof(buf), f)))
+        fwrite(buf, ret, 1, stdout);
+
+    fclose(f);
+    return 0;
+}

unikernel-demo/fs1/unistd/Makefile

@@ -0,0 +1,3 @@
+export ukl-obj-m := main.o
+
+include ../../Makefile