initial working example as made hacking around

.config.helloworld_qemu-x86_64

@@ -0,0 +1,310 @@
+#
+# Automatically generated file; DO NOT EDIT.
+# Unikraft/0.17.0~8838cfd Configuration
+#
+CONFIG_UK_FULLVERSION="0.17.0~8838cfd"
+CONFIG_UK_CODENAME="Calypso"
+CONFIG_UK_ARCH="x86_64"
+CONFIG_HOST_ARCH="x86_64"
+CONFIG_UK_BASE="/home/lobo/home/unikraft-zig-native-hello/.unikraft/unikraft"
+CONFIG_UK_APP="/home/lobo/home/unikraft-zig-native-hello"
+CONFIG_UK_DEFNAME="helloworld"
+
+#
+# Architecture Selection
+#
+CONFIG_ARCH_X86_64=y
+# CONFIG_ARCH_ARM_64 is not set
+# CONFIG_ARCH_ARM_32 is not set
+# CONFIG_MARCH_X86_64_NATIVE is not set
+CONFIG_MARCH_X86_64_GENERIC=y
+# CONFIG_MARCH_X86_64_NOCONA is not set
+# CONFIG_MARCH_X86_64_CORE2 is not set
+# CONFIG_MARCH_X86_64_COREI7 is not set
+# CONFIG_MARCH_X86_64_COREI7AVX is not set
+# CONFIG_MARCH_X86_64_COREI7AVXI is not set
+# CONFIG_MARCH_X86_64_ATOM is not set
+# CONFIG_MARCH_X86_64_K8 is not set
+# CONFIG_MARCH_X86_64_K8SSE3 is not set
+# CONFIG_MARCH_X86_64_AMDFAM10 is not set
+# CONFIG_MARCH_X86_64_BTVER1 is not set
+# CONFIG_MARCH_X86_64_BDVER1 is not set
+# CONFIG_MARCH_X86_64_BDVER2 is not set
+# CONFIG_MARCH_X86_64_BDVER3 is not set
+# CONFIG_MARCH_X86_64_BTVER2 is not set
+
+#
+# Processor Features
+#
+CONFIG_X86_64_HAVE_RANDOM=y
+# end of Processor Features
+
+CONFIG_STACK_SIZE_PAGE_ORDER=4
+CONFIG_CPU_EXCEPT_STACK_SIZE_PAGE_ORDER=4
+CONFIG_AUXSTACK_SIZE_PAGE_ORDER=4
+CONFIG_HAVE_RANDOM=y
+# end of Architecture Selection
+
+#
+# Platform Configuration
+#
+CONFIG_PLAT_KVM=y
+CONFIG_KVM_BOOT_PROTO_MULTIBOOT=y
+
+#
+# Hint: EFI stub depends on OPTIMIZE_PIE
+#
+CONFIG_KVM_VMM_QEMU=y
+# CONFIG_KVM_VMM_FIRECRACKER is not set
+
+#
+# Console Options
+#
+CONFIG_KVM_KERNEL_VGA_CONSOLE=y
+CONFIG_KVM_DEBUG_SERIAL_CONSOLE=y
+CONFIG_KVM_DEBUG_VGA_CONSOLE=y
+CONFIG_KVM_KERNEL_SERIAL_CONSOLE=y
+
+#
+# Serial console configuration
+#
+CONFIG_KVM_SERIAL_BAUD_115200=y
+# CONFIG_KVM_SERIAL_BAUD_57600 is not set
+# CONFIG_KVM_SERIAL_BAUD_38400 is not set
+# CONFIG_KVM_SERIAL_BAUD_19200 is not set
+# end of Serial console configuration
+# end of Console Options
+
+# CONFIG_PLAT_XEN is not set
+
+#
+# Platform Interface Options
+#
+# CONFIG_UKPLAT_MEMRNAME is not set
+CONFIG_UKPLAT_MEMREGION_MAX_COUNT=128
+# CONFIG_UKPLAT_ACPI is not set
+CONFIG_UKPLAT_LCPU_MAXCOUNT=1
+# CONFIG_PAGING is not set
+# end of Platform Interface Options
+
+CONFIG_HZ=100
+# end of Platform Configuration
+
+#
+# Device Drivers
+#
+
+#
+# Real Time Clock
+#
+# end of Real Time Clock
+
+#
+# Serial console
+#
+# end of Serial console
+
+#
+# Bus drivers
+#
+CONFIG_HAVE_PCI=y
+# CONFIG_LIBUKBUS_PCI is not set
+# CONFIG_LIBUKBUS_PLATFORM is not set
+# end of Bus drivers
+
+#
+# Interrupt controller
+#
+CONFIG_HAVE_APIC=y
+CONFIG_LIBUKINTCTLR_XPIC=y
+# CONFIG_LIBUKINTCTLR_APIC is not set
+# end of Interrupt controller
+
+#
+# Virtio
+#
+CONFIG_HAVE_MMIO=y
+# end of Virtio
+
+#
+# Xen
+#
+# end of Xen
+# end of Device Drivers
+
+#
+# Library Configuration
+#
+CONFIG_LIBISRLIB=y
+CONFIG_LIBNOLIBC=y
+CONFIG_LIBNOLIBC_UKDEBUG_ASSERT=y
+# CONFIG_LIBNOLIBC_SYSLOG is not set
+CONFIG_LIBNOLIBC_FD_SETSIZE=64
+# CONFIG_LIBPOSIX_ENVIRON is not set
+# CONFIG_LIBPOSIX_EVENTFD is not set
+# CONFIG_LIBPOSIX_FDIO is not set
+# CONFIG_LIBPOSIX_FDTAB is not set
+# CONFIG_LIBPOSIX_FUTEX is not set
+# CONFIG_LIBPOSIX_LIBDL is not set
+# CONFIG_LIBPOSIX_PIPE is not set
+# CONFIG_LIBPOSIX_POLL is not set
+CONFIG_LIBPOSIX_PROCESS=y
+CONFIG_LIBPOSIX_PROCESS_PIDS=y
+CONFIG_LIBPOSIX_PROCESS_MAX_PID=31
+CONFIG_LIBPOSIX_PROCESS_INIT_PIDS=y
+# CONFIG_LIBPOSIX_PROCESS_CLONE is not set
+# CONFIG_LIBPOSIX_PROCESS_DEBUG is not set
+# CONFIG_LIBPOSIX_SOCKET is not set
+# CONFIG_LIBPOSIX_SYSINFO is not set
+# CONFIG_LIBPOSIX_TIME is not set
+# CONFIG_LIBPOSIX_TIMERFD is not set
+# CONFIG_LIBPOSIX_TTY is not set
+# CONFIG_LIBPOSIX_UNIXSOCKET is not set
+# CONFIG_LIBPOSIX_USER is not set
+# CONFIG_LIBSYSCALL_SHIM is not set
+# CONFIG_LIBUBSAN is not set
+# CONFIG_LIBUK9P is not set
+CONFIG_LIBUKALLOC=y
+# CONFIG_LIBUKALLOC_IFMALLOC is not set
+# CONFIG_LIBUKALLOC_IFSTATS is not set
+CONFIG_LIBUKALLOCBBUDDY=y
+# CONFIG_LIBUKALLOCBBUDDY_FREELIST_SANITY is not set
+# CONFIG_LIBUKALLOCPOOL is not set
+# CONFIG_LIBUKALLOCREGION is not set
+CONFIG_LIBUKALLOCSTACK=y
+CONFIG_LIBUKARGPARSE=y
+# CONFIG_LIBUKARGPARSE_TEST is not set
+CONFIG_LIBUKATOMIC=y
+CONFIG_LIBUKBITOPS=y
+# CONFIG_LIBUKBLKDEV is not set
+CONFIG_LIBUKBOOT=y
+# CONFIG_LIBUKBOOT_BANNER_NONE is not set
+# CONFIG_LIBUKBOOT_BANNER_MINIMAL is not set
+# CONFIG_LIBUKBOOT_BANNER_CLASSIC is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_ANSI is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_ANSI2 is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_EA is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_EAANSI is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_EAANSI2 is not set
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_U8 is not set
+CONFIG_LIBUKBOOT_BANNER_POWEREDBY_U8ANSI=y
+# CONFIG_LIBUKBOOT_BANNER_POWEREDBY_U8ANSI2 is not set
+CONFIG_LIBUKBOOT_MAXNBARGS=60
+CONFIG_LIBUKBOOT_INITALLOC=y
+CONFIG_LIBUKBOOT_INITBBUDDY=y
+# CONFIG_LIBUKBOOT_INITREGION is not set
+# CONFIG_LIBUKBOOT_INITNOALLOC is not set
+CONFIG_LIBUKBOOT_INITSCHED=y
+CONFIG_LIBUKBOOT_INITSCHEDCOOP=y
+# CONFIG_LIBUKBOOT_INITNOSCHED is not set
+# CONFIG_LIBUKBOOT_MAINTHREAD is not set
+CONFIG_LIBUKBOOT_ALLOCSTACK=y
+# CONFIG_LIBUKBUS is not set
+CONFIG_LIBUKDEBUG=y
+CONFIG_LIBUKDEBUG_PRINTK=y
+# CONFIG_LIBUKDEBUG_PRINTK_INFO is not set
+# CONFIG_LIBUKDEBUG_PRINTK_WARN is not set
+CONFIG_LIBUKDEBUG_PRINTK_ERR=y
+# CONFIG_LIBUKDEBUG_PRINTK_CRIT is not set
+# CONFIG_LIBUKDEBUG_PRINTD is not set
+# CONFIG_LIBUKDEBUG_NOREDIR is not set
+CONFIG_LIBUKDEBUG_REDIR_PRINTD=y
+# CONFIG_LIBUKDEBUG_REDIR_PRINTK is not set
+CONFIG_LIBUKDEBUG_PRINT_TIME=y
+# CONFIG_LIBUKDEBUG_PRINT_THREAD is not set
+# CONFIG_LIBUKDEBUG_PRINT_CALLER is not set
+CONFIG_LIBUKDEBUG_PRINT_SRCNAME=y
+# CONFIG_LIBUKDEBUG_ANSI_COLOR is not set
+CONFIG_LIBUKDEBUG_ENABLE_ASSERT=y
+# CONFIG_LIBUKDEBUG_TRACEPOINTS is not set
+# CONFIG_LIBUKFALLOC is not set
+# CONFIG_LIBUKFALLOCBUDDY is not set
+CONFIG_LIBUKFILE=y
+# CONFIG_LIBUKGCOV is not set
+CONFIG_HAVE_INTCTLR=y
+CONFIG_LIBUKINTCTLR=y
+CONFIG_LIBUKINTCTLR_MAX_HANDLERS_PER_IRQ=8
+# CONFIG_LIBUKINTCTLR_ISR_ECTX_ASSERTIONS is not set
+CONFIG_LIBUKLIBID=y
+CONFIG_LIBUKLIBID_INFO=y
+
+#
+# Global metadata
+#
+CONFIG_LIBUKLIBID_INFO_UKFULLVERSION=y
+# CONFIG_LIBUKLIBID_INFO_UKCODENAME is not set
+# CONFIG_LIBUKLIBID_INFO_COMPILER is not set
+CONFIG_LIBUKLIBID_INFO_COMPILEDATE=y
+# CONFIG_LIBUKLIBID_INFO_UKCONFIGGZ is not set
+# end of Global metadata
+
+#
+# Per library metadata
+#
+# CONFIG_LIBUKLIBID_INFO_LIB_UKVERSION is not set
+# CONFIG_LIBUKLIBID_INFO_LIB_UKCODENAME is not set
+CONFIG_LIBUKLIBID_INFO_LIB_COMPILER=y
+# CONFIG_LIBUKLIBID_INFO_LIB_COMPILEDATE is not set
+# end of Per library metadata
+
+# CONFIG_LIBUKLIBID_INFO_COMPILEDBY is not set
+# CONFIG_LIBUKLIBID_INFO_BOOTDUMP is not set
+# CONFIG_LIBUKLIBPARAM is not set
+CONFIG_LIBUKLOCK=y
+CONFIG_LIBUKLOCK_SEMAPHORE=y
+CONFIG_LIBUKLOCK_MUTEX=y
+# CONFIG_LIBUKLOCK_MUTEX_METRICS is not set
+CONFIG_LIBUKLOCK_RWLOCK=y
+# CONFIG_LIBUKMMAP is not set
+# CONFIG_LIBUKMPI is not set
+# CONFIG_LIBUKNETDEV is not set
+# CONFIG_LIBUKNOFAULT is not set
+CONFIG_LIBUKRANDOM=y
+# CONFIG_LIBUKRANDOM_SEED_INSECURE is not set
+# CONFIG_LIBUKRING is not set
+# CONFIG_LIBUKRUST is not set
+CONFIG_LIBUKSCHED=y
+# CONFIG_LIBUKSCHED_DEBUG is not set
+CONFIG_LIBUKSCHEDCOOP=y
+# CONFIG_LIBUKSGLIST is not set
+# CONFIG_LIBUKSIGNAL is not set
+# CONFIG_LIBUKSP is not set
+# CONFIG_LIBUKSTORE is not set
+CONFIG_LIBUKSTREAMBUF=y
+# CONFIG_LIBUKSTREAMBUF_TEST is not set
+# CONFIG_LIBUKTEST is not set
+CONFIG_LIBUKTIMECONV=y
+# CONFIG_LIBUKVMEM is not set
+# CONFIG_LIBVFSCORE is not set
+CONFIG_HAVE_BOOTENTRY=y
+CONFIG_HAVE_SCHED=y
+# end of Library Configuration
+
+#
+# Application Options
+#
+
+#
+# Build Options
+#
+CONFIG_OPTIMIZE_NONE=y
+# CONFIG_OPTIMIZE_PERF is not set
+# CONFIG_OPTIMIZE_SIZE is not set
+CONFIG_OPTIMIZE_NOOMITFP=y
+# CONFIG_OPTIMIZE_DEADELIM is not set
+# CONFIG_OPTIMIZE_LTO is not set
+# CONFIG_OPTIMIZE_PIE is not set
+# CONFIG_DEBUG_SYMBOLS_LVL0 is not set
+# CONFIG_DEBUG_SYMBOLS_LVL1 is not set
+# CONFIG_DEBUG_SYMBOLS_LVL2 is not set
+CONFIG_DEBUG_SYMBOLS_LVL3=y
+# CONFIG_OPTIMIZE_WARNISERROR is not set
+# CONFIG_OPTIMIZE_SYMFILE is not set
+# CONFIG_OPTIMIZE_COMPRESS is not set
+# CONFIG_RECORD_BUILDTIME is not set
+CONFIG_CROSS_COMPILE=""
+CONFIG_LLVM_TARGET_ARCH=""
+# end of Build Options
+
+CONFIG_UK_NAME="helloworld"

.gitignore

@@ -0,0 +1,2 @@
+.zig-cache
+zig-out

Kraftfile

@@ -0,0 +1,13 @@
+spec: v0.6
+
+name: helloworld
+
+unikraft:
+  version: stable
+
+targets:
+- fc/arm64
+- fc/x86_64
+- qemu/arm64
+- qemu/x86_64
+- xen/x86_64

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Emil Lerch
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile.uk

@@ -0,0 +1,5 @@
+$(eval $(call addlib,apphelloworld))
+
+APPHELLOWORLD_SRCS-y += $(APPHELLOWORLD_BASE)/helloworld.c
+APPHELLOWORLD_SRCS-y += $(APPHELLOWORLD_BASE)/undefined.c
+UK_ALIBS-y += $(APPHELLOWORLD_BASE)/libziggy.a

README.md

@@ -0,0 +1,2 @@
+(cd ziggy && zig build -Doptimize=ReleaseSafe -Dtarget=x86_64-linux-gnu.2.13 -Dcpu=baseline) && cp ziggy/zig-out/lib/libziggy.a . &&  kraft build --plat qemu --arch x86_64 --log-level debug --log-type basic && kraft run --pla
+t qemu --arch x86_64

helloworld.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <unistd.h>
+
+extern int add(int, int);
+extern int gettid(void);
+
+int main(void)
+{
+	int result = add(2, 2);
+	/* write(1, "from helloworld", 15); */
+	printf("Hello, World! 2+2=");
+	char buffer[10];
+	for (int i = 0; i < 10; i++ ) buffer[i] = 0;
+	buffer[0] = '0' + result;
+	puts(buffer);
+
+	// requires posix-process, process and thread ids
+	puts("Attempting gettid()");
+	printf("tid=%d\n", gettid());
+
+	return 0;
+}

undefined.c

@@ -0,0 +1,196 @@
+#include <stdio.h>
+
+/* Linking our zig to libc results in the following undefined symbols:
+	mmap64
+	dl_iterate_phdr
+	getcontext
+	sigaction
+	write
+	close
+	realpath
+	read
+	msync
+	munmap
+	environ
+	openat64
+	flock
+	fstat64
+	dl_iterate_phdr
+	getenv
+	isatty
+ */
+
+// Provide stubs for missing functions
+#define UNUSED(x) (void)(x)
+#define SEGFAULT() {int *ptr = 0; *ptr = 42;}
+void *mmap64(void *addr, size_t length, int prot, int flags,
+                  int fd, long int offset){
+	UNUSED(addr);
+	UNUSED(length);
+	UNUSED(prot);
+	UNUSED(flags);
+	UNUSED(flags);
+	UNUSED(fd);
+	UNUSED(offset);
+	puts("unsupported function mmap called");
+	// force a seg fault
+  SEGFAULT();
+	return 0; // unreachable
+}
+
+int dl_iterate_phdr(
+                 int (*callback)(struct dl_phdr_info *info,
+                                 size_t size, void *data),
+                 void *data){
+	UNUSED(callback);
+	UNUSED(data);
+	puts("unsupported function dl_iterate_phdr called");
+  SEGFAULT();
+  return 0;
+}
+int getcontext(void *ucp) {
+	UNUSED(ucp);
+	puts("unsupported function getcontext called");
+  SEGFAULT();
+  return 0;
+ }
+
+int sigaction(int signum, void* act, void* oldact) {
+	UNUSED(signum);
+	UNUSED(act);
+	UNUSED(oldact);
+                     // const struct sigaction *_Nullable restrict act,
+                     // struct sigaction *_Nullable restrict oldact) {
+	puts("unsupported function sigaction called");
+  SEGFAULT();
+  return 0;
+}
+
+#define ANSI_COLOR_RED     "\x1b[31m"
+#define ANSI_COLOR_GREEN   "\x1b[32m"
+#define ANSI_COLOR_YELLOW  "\x1b[33m"
+#define ANSI_COLOR_BLUE    "\x1b[34m"
+#define ANSI_COLOR_MAGENTA "\x1b[35m"
+#define ANSI_COLOR_CYAN    "\x1b[36m"
+#define ANSI_COLOR_RESET   "\x1b[0m"
+
+// TODO: This if is not correct
+#if !(defined(CONFIG_LIBPOSIX_TTY) || defined(CONFIG_LIBSYSCALL_SHIM))
+	size_t write(int fd, const char *buf, size_t count){
+		UNUSED(fd);
+		UNUSED(buf);
+		UNUSED(count);
+		char *color;
+		switch (fd) {
+			case 1: // stdout
+				color = ANSI_COLOR_RESET;
+				break;
+			case 2:
+				color = ANSI_COLOR_RED;
+				break;
+			default:
+				printf("write called on unsupported file descriptor: ");
+				char fd_buf[10] = "fd = ";
+				fd_buf[5] = '0' + fd;
+				fd_buf[6] = 0;
+				puts(fd_buf);
+				SEGFAULT();
+				break;
+		}
+		if (fd != 1) printf(color);
+		if (fd == 2) printf("(stderr): ");
+		printf("%.*s", (int)count, buf);
+		if (fd != 1) printf(ANSI_COLOR_RESET);
+		return count;
+	}
+
+	int close(int fd) {
+		UNUSED(fd);
+											 // const struct sigaction *_Nullable restrict act,
+											 // struct sigaction *_Nullable restrict oldact) {
+		puts("unsupported function close called");
+		SEGFAULT();
+		return 0;
+	}
+	size_t read(int fd, void *buf, size_t count) {
+		UNUSED(fd);
+		UNUSED(buf);
+		UNUSED(count);
+		puts("unsupported function read called");
+		SEGFAULT();
+		return 0;
+	}
+#endif
+
+char *realpath(const char *path,
+                      char *resolved_path) {
+	UNUSED(path);
+	UNUSED(resolved_path);
+                     // const struct sigaction *_Nullable restrict act,
+                     // struct sigaction *_Nullable restrict oldact) {
+	puts("unsupported function realpath called");
+  SEGFAULT();
+  return 0;
+}
+
+int msync(void *addr, size_t length, int flags) {
+	UNUSED(addr);
+	UNUSED(length);
+	UNUSED(flags);
+	puts("unsupported function msync called");
+  SEGFAULT();
+  return 0;
+}
+int munmap(void *addr, size_t length) {
+	UNUSED(addr);
+	UNUSED(length);
+	puts("unsupported function munmap called");
+  SEGFAULT();
+  return 0;
+}
+
+int openat64(int fd, const char * path, int oflag, ...) {
+	UNUSED(fd);
+	UNUSED(path);
+	UNUSED(oflag);
+	puts("unsupported function openat64 called");
+  SEGFAULT();
+  return 0;
+}
+
+int flock(int fd, int operation) {
+	UNUSED(fd);
+	UNUSED(operation);
+	puts("unsupported function flock called");
+  SEGFAULT();
+  return 0;
+}
+
+int fstat64(int fd, void *statbuf) {
+	UNUSED(fd);
+	UNUSED(statbuf);
+	puts("unsupported function fstat called");
+  SEGFAULT();
+  return 0;
+}
+// If .config... file has environment support (CONFIG_LIBPOSIX_ENVIRON=y)
+// defined, these variable are handled
+#ifndef CONFIG_LIBPOSIX_ENVIRON
+	char **environ = 0;
+	char *getenv(const char *name) {
+		UNUSED(name);
+		puts(ANSI_COLOR_RED);
+		puts("unsupported function getenv called. use `kraft menu` to configure environment variable support");
+		puts("or set CONFIG_LIBPOSIX_ENVIRON in .config.<appname>_<system>-<architecture>");
+		puts(ANSI_COLOR_RESET);
+		SEGFAULT();
+		return 0;
+	}
+#endif
+
+int isatty(int fd) {
+	UNUSED(fd);
+	puts("unsupported function isatty called");
+  SEGFAULT();
+  return 0;
+}

ziggy/build.zig

@@ -0,0 +1,92 @@
+const std = @import("std");
+
+// Although this function looks imperative, note that its job is to
+// declaratively construct a build graph that will be executed by an external
+// runner.
+pub fn build(b: *std.Build) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
+
+    const lib = b.addStaticLibrary(.{
+        .name = "ziggy",
+        // In this case the main source file is merely a path, however, in more
+        // complicated build scripts, this could be a generated file.
+        .root_source_file = b.path("src/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+    lib.bundle_compiler_rt = true; // necessary since we're linking with a c program
+    lib.linkLibC();
+    // This declares intent for the library to be installed into the standard
+    // location when the user invokes the "install" step (the default step when
+    // running `zig build`).
+    b.installArtifact(lib);
+
+    const exe = b.addExecutable(.{
+        .name = "ziggy",
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    // This declares intent for the executable to be installed into the
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
+    b.installArtifact(exe);
+
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
+    const run_cmd = b.addRunArtifact(exe);
+
+    // By making the run step depend on the install step, it will be run from the
+    // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    // This allows the user to pass arguments to the application in the build
+    // command itself, like this: `zig build run -- arg1 arg2 etc`
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    // Creates a step for unit testing. This only builds the test executable
+    // but does not run it.
+    const lib_unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
+
+    // Similar to creating the run step earlier, this exposes a `test` step to
+    // the `zig build --help` menu, providing a way for the user to request
+    // running the unit tests.
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_lib_unit_tests.step);
+    test_step.dependOn(&run_exe_unit_tests.step);
+}

ziggy/build.zig.zon

@@ -0,0 +1,72 @@
+.{
+    // This is the default name used by packages depending on this one. For
+    // example, when a user runs `zig fetch --save <url>`, this field is used
+    // as the key in the `dependencies` table. Although the user can choose a
+    // different name, most users will stick with this provided value.
+    //
+    // It is redundant to include "zig" in this name because it is already
+    // within the Zig package namespace.
+    .name = "ziggy",
+
+    // This is a [Semantic Version](https://semver.org/).
+    // In a future version of Zig it will be used for package deduplication.
+    .version = "0.0.0",
+
+    // This field is optional.
+    // This is currently advisory only; Zig does not yet do anything
+    // with this value.
+    //.minimum_zig_version = "0.11.0",
+
+    // This field is optional.
+    // Each dependency must either provide a `url` and `hash`, or a `path`.
+    // `zig build --fetch` can be used to fetch all dependencies of a package, recursively.
+    // Once all dependencies are fetched, `zig build` no longer requires
+    // internet connectivity.
+    .dependencies = .{
+        // See `zig fetch --save <url>` for a command-line interface for adding dependencies.
+        //.example = .{
+        //    // When updating this field to a new URL, be sure to delete the corresponding
+        //    // `hash`, otherwise you are communicating that you expect to find the old hash at
+        //    // the new URL.
+        //    .url = "https://example.com/foo.tar.gz",
+        //
+        //    // This is computed from the file contents of the directory of files that is
+        //    // obtained after fetching `url` and applying the inclusion rules given by
+        //    // `paths`.
+        //    //
+        //    // This field is the source of truth; packages do not come from a `url`; they
+        //    // come from a `hash`. `url` is just one of many possible mirrors for how to
+        //    // obtain a package matching this `hash`.
+        //    //
+        //    // Uses the [multihash](https://multiformats.io/multihash/) format.
+        //    .hash = "...",
+        //
+        //    // When this is provided, the package is found in a directory relative to the
+        //    // build root. In this case the package's hash is irrelevant and therefore not
+        //    // computed. This field and `url` are mutually exclusive.
+        //    .path = "foo",
+
+        //    // When this is set to `true`, a package is declared to be lazily
+        //    // fetched. This makes the dependency only get fetched if it is
+        //    // actually used.
+        //    .lazy = false,
+        //},
+    },
+
+    // Specifies the set of files and directories that are included in this package.
+    // Only files and directories listed here are included in the `hash` that
+    // is computed for this package. Only files listed here will remain on disk
+    // when using the zig package manager. As a rule of thumb, one should list
+    // files required for compilation plus any license(s).
+    // Paths are relative to the build root. Use the empty string (`""`) to refer to
+    // the build root itself.
+    // A directory listed here means that all files within, recursively, are included.
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "src",
+        // For example...
+        //"LICENSE",
+        //"README.md",
+    },
+}

ziggy/src/main.zig

@@ -0,0 +1,24 @@
+const std = @import("std");
+
+pub fn main() !void {
+    // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
+    std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
+
+    // stdout is for the actual output of your application, for example if you
+    // are implementing gzip, then only the compressed bytes should be sent to
+    // stdout, not any debugging messages.
+    const stdout_file = std.io.getStdOut().writer();
+    var bw = std.io.bufferedWriter(stdout_file);
+    const stdout = bw.writer();
+
+    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+
+    try bw.flush(); // don't forget to flush!
+}
+
+test "simple test" {
+    var list = std.ArrayList(i32).init(std.testing.allocator);
+    defer list.deinit(); // try commenting this out and see if zig detects the memory leak!
+    try list.append(42);
+    try std.testing.expectEqual(@as(i32, 42), list.pop());
+}

ziggy/src/root.zig

@@ -0,0 +1,43 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const testing = std.testing;
+
+pub extern "c" fn gettid() std.c.pid_t;
+
+export fn add(a: i32, b: i32) i32 {
+    if (builtin.mode == .Debug) {
+        const out = std.io.getStdErr().writer();
+        out.print("WARNING: Building debug mode will likely crash in Unikraft environment. Use -Doptimize=ReleaseSafe\n", .{}) catch {};
+    }
+    const out = std.io.getStdOut().writer();
+    out.print("Hello from lib\n", .{}) catch {};
+    std.log.err("logging error", .{});
+    out.print("Checking thread id\n", .{}) catch {};
+    out.print("WAT: {d}\n", .{gettid()}) catch {};
+    out.print("Thread id: {d}\n", .{gettid()}) catch {};
+    // out.print("Thread id: {d}\n", .{std.Thread.getCurrentId()}) catch {};
+    // We have a theory we need posix-futex enabled for locking/unlocking
+    // std.debug.print("debug print", .{});
+    // if (builtin.single_threaded) @compileError("single threaded");
+    return a + b + 1;
+}
+
+// Unhandled Trap 6 (invalid opcode), error code=0x0
+//
+// Thread.getCurrentId() calls fall flat. It looks like they use the linux
+// call gettid, but that is not implemented by unikraft as of 0.17.0 (I
+// believe). I tried adding process/thread support, but that did not address
+// the problem. getCurrentId is used by the following:
+//
+// Mutex (only when building debug mode)
+// Condition  (only when building in debug mode)
+// std.debug panic implementation
+//
+// So:
+// 1) don't call it ourselves
+// 2) build in release mode
+// 3) don't panic ;-)
+
+test "basic add functionality" {
+    try testing.expect(add(3, 7) == 10);
+}