sys: add userspace bootstrap program

sys/bootstrap/CMakeLists.txt

@@ -0,0 +1,14 @@
+file(GLOB c_sources *.c *.h)
+file(GLOB arch_sources arch/${CMAKE_SYSTEM_PROCESSOR}/*.S)
+
+set_property(SOURCE ${arch_sources} PROPERTY LANGUAGE C)
+
+add_executable(bootstrap ${c_sources} ${arch_sources})
+
+target_link_libraries(bootstrap libmango ulibc liblaunch)
+
+target_compile_options(bootstrap PRIVATE
+	-fPIC -pie -fno-stack-protector -nostdlib -ffreestanding)
+target_link_options(bootstrap PRIVATE
+	-fPIC -static -pie -nostdlib -ffreestanding
+	-T ${CMAKE_CURRENT_SOURCE_DIR}/arch/${TARGET_ARCH}/layout.ld)

sys/bootstrap/arch/x86_64/layout.ld

@@ -0,0 +1,18 @@
+ENTRY(_start)
+
+SECTIONS {
+	.text ALIGN(4K) : {
+		*(.text)
+		*(.rodata)
+	}
+
+	.data ALIGN(4K) : {
+		*(.data)
+		*(.bss)
+	}
+
+	/DISCARD/ : {
+		*(.interp)
+		*(.dynamic)
+	}
+}

sys/bootstrap/arch/x86_64/start.S

@@ -0,0 +1,15 @@
+.code64
+
+.global _start
+.type _start, @function
+
+.extern main
+.type main, @function
+
+.extern exit
+.type exit, @function
+
+_start:
+	call main
+1:	pause
+	jmp 1b

sys/bootstrap/main.c

@@ -0,0 +1,99 @@
+#include "tar.h"
+
+#include <launch.h>
+#include <mango/log.h>
+#include <mango/msg.h>
+#include <mango/task.h>
+#include <mango/types.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#define INIT_PATH "/usr/bin/test"
+
+static enum launch_status resolve_dependency(
+	struct launch_ctx *ctx,
+	const char *name,
+	kern_handle_t *out,
+	void *arg)
+{
+	char s[128];
+	while (*name == '/') {
+		name++;
+	}
+
+	snprintf(s, sizeof s, "searching for library %s", name);
+	kern_log(s);
+
+	struct tar *fs = arg;
+	struct tar_file file = {0};
+	if (tar_open(fs, name, &file) != 0) {
+		snprintf(s, sizeof s, "cannot find library %s", name);
+		kern_log(s);
+		return LAUNCH_ERR_CANNOT_RESOLVE_DEPENDENCY;
+	}
+
+	kern_handle_t image = KERN_HANDLE_INVALID;
+	int err = tar_file_create_vm_object(&file, &image);
+	if (err != 0) {
+		snprintf(s, sizeof s, "cannot load library %s", name);
+		kern_log(s);
+		return -1;
+	}
+
+	*out = image;
+	return LAUNCH_OK;
+}
+
+int main(
+	int argc,
+	const char **argv,
+	kern_handle_t task,
+	kern_handle_t address_space,
+	uintptr_t bsp_base)
+{
+	struct tar bsp = {0};
+	if (tar_init(&bsp, bsp_base) != 0) {
+		kern_log("cannot access bsp");
+		return -1;
+	}
+
+	struct tar_file init = {0};
+	if (tar_open(&bsp, INIT_PATH, &init) != 0) {
+		kern_log("cannot find init program " INIT_PATH);
+		return -1;
+	}
+
+	kern_trace("loading " INIT_PATH);
+
+	kern_handle_t image = KERN_HANDLE_INVALID;
+	int err = tar_file_create_vm_object(&init, &image);
+	if (err != 0) {
+		kern_log("cannot load executable " INIT_PATH);
+		return -1;
+	}
+
+	kern_trace("loaded executable vm-object " INIT_PATH);
+
+	kern_tracef("task=%x, region=%x", task, address_space);
+
+	struct launch_ctx launch;
+	struct launch_result result;
+	struct launch_parameters params = {
+		.p_executable = image,
+		.p_parent_task = task,
+		.p_task_name = "init",
+		.p_local_address_space = address_space,
+		.p_resolver_arg = &bsp,
+	};
+
+	launch_ctx_init(&launch);
+	launch.ctx_resolve_library = resolve_dependency;
+
+	enum launch_status status
+		= launch_ctx_execute(&launch, &params, LAUNCH_F_NONE, &result);
+
+	kern_tracef("launch result: %d", status);
+
+	return 102;
+}

sys/bootstrap/tar.c

@@ -0,0 +1,96 @@
+#include "tar.h"
+
+#include <mango/handle.h>
+#include <mango/vm.h>
+#include <string.h>
+
+size_t getsize(const char *in)
+{
+	size_t size = 0;
+	size_t j;
+	size_t count = 1;
+
+	for (j = 11; j > 0; j--, count *= 8) {
+		size += ((in[j - 1] - '0') * count);
+	}
+
+	return size;
+}
+
+int tar_init(struct tar *tar, uintptr_t base)
+{
+	memset(tar, 0x0, sizeof *tar);
+	tar->tar_entries = (struct tar_bin_header *)base;
+	return 0;
+}
+
+int tar_open(struct tar *tar, const char *path, struct tar_file *out)
+{
+	while (*path == '/') {
+		path++;
+	}
+
+	if (*path == '\0') {
+		return -1;
+	}
+
+	struct tar_bin_header *bin_header = tar->tar_entries;
+	struct tar_header header;
+	for (size_t i = 0;; i++) {
+		tar_header_decode(bin_header, &header);
+		if (bin_header->filename[0] == 0) {
+			break;
+		}
+
+		char *s = (char *)bin_header;
+		s += sizeof *bin_header;
+
+		if (!strcmp(bin_header->filename, path)) {
+			out->f_header = header;
+			out->f_data = s;
+			return 0;
+		}
+
+		s += header.size;
+		s += ((sizeof *bin_header)
+		      - ((uintptr_t)s % (sizeof *bin_header)));
+
+		bin_header = (struct tar_bin_header *)s;
+	}
+
+	return -1;
+}
+
+int tar_file_create_vm_object(const struct tar_file *file, kern_handle_t *out)
+{
+	const void *data = file->f_data;
+	size_t len = file->f_header.size;
+	kern_handle_t vmo = KERN_HANDLE_INVALID;
+
+	kern_status_t status = vm_object_create(
+		NULL,
+		0,
+		file->f_header.size,
+		VM_PROT_READ | VM_PROT_EXEC | VM_PROT_USER,
+		&vmo);
+	if (status != KERN_OK) {
+		return -1;
+	}
+
+	size_t nr_written = 0;
+	status = vm_object_write(vmo, data, 0, len, &nr_written);
+	if (status != KERN_OK || nr_written != len) {
+		kern_handle_close(vmo);
+		return -1;
+	}
+
+	*out = vmo;
+	return 0;
+}
+
+int tar_header_decode(const struct tar_bin_header *in, struct tar_header *out)
+{
+	memcpy(out->filename, in->filename, sizeof out->filename);
+	out->size = getsize(in->size);
+	return 0;
+}

sys/bootstrap/tar.h

@@ -0,0 +1,45 @@
+#ifndef TAR_H_
+#define TAR_H_
+
+#include <mango/types.h>
+#include <stddef.h>
+#include <stdint.h>
+
+struct tar {
+	struct tar_bin_header *tar_entries;
+};
+
+struct tar_bin_header {
+	char filename[100];
+	char mode[8];
+	char uid[8];
+	char gid[8];
+	char size[12];
+	char mtime[12];
+	char chksum[8];
+	char typeflag[1];
+} __attribute__((aligned(512)));
+
+struct tar_header {
+	char filename[100];
+	size_t size;
+};
+
+struct tar_file {
+	struct tar_header f_header;
+	const void *f_data;
+};
+
+extern int tar_init(struct tar *tar, uintptr_t base);
+
+extern int tar_open(struct tar *tar, const char *path, struct tar_file *out);
+
+extern int tar_file_create_vm_object(
+	const struct tar_file *file,
+	kern_handle_t *out);
+
+extern int tar_header_decode(
+	const struct tar_bin_header *in,
+	struct tar_header *out);
+
+#endif