Embedded Assets¶

ELMOS embeds templates and headers at compile time using Go's embed package.

Directory Structure¶

assets/
├── embed.go              # Embed directives and accessor functions
├── libraries/            # macOS compatibility headers
│   ├── elf.h             # ELF definitions
│   ├── byteswap.h        # Byte swapping macros
│   └── asm/
│       └── bitsperlong.h # Architecture bit width
├── templates/
│   ├── app/              # Userspace app templates
│   │   ├── main.c.tmpl
│   │   └── Makefile.tmpl
│   ├── configs/          # Configuration templates
│   │   └── elmos.yaml.tmpl
│   ├── init/             # Guest init scripts
│   │   ├── init.sh.tmpl
│   │   └── guesync.sh.tmpl
│   └── module/           # Kernel module templates
│       ├── module.c.tmpl
│       └── Makefile.tmpl
└── toolchains/
    └── configs/          # Crosstool-ng configurations

Embed Directives¶

// assets/embed.go
package assets

import "embed"

//go:embed templates/*
var Templates embed.FS

Accessor Functions¶

Function	Returns
`GetModuleTemplate()`	`templates/module/module.c.tmpl`
`GetModuleMakefile()`	`templates/module/Makefile.tmpl`
`GetAppTemplate()`	`templates/app/main.c.tmpl`
`GetAppMakefile()`	`templates/app/Makefile.tmpl`
`GetInitScript()`	`templates/init/init.sh.tmpl`
`GetGuestSync()`	`templates/init/guesync.sh.tmpl`
`GetConfigTemplate()`	`templates/configs/elmos.yaml.tmpl`

Usage:

tmpl, err := assets.GetModuleTemplate()
if err != nil {
    return err
}
// Use tmpl bytes...

Template Variables¶

Module Template¶

// templates/module/module.c.tmpl
#include <linux/module.h>
#include <linux/kernel.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("{{.Author}}");
MODULE_DESCRIPTION("{{.Description}}");

static int __init {{.Name}}_init(void) {
    pr_info("{{.Name}}: loaded\n");
    return 0;
}
module_init({{.Name}}_init);

App Template¶

// templates/app/main.c.tmpl
#include <stdio.h>

int main(void) {
    printf("Hello from {{.Name}}!\n");
    return 0;
}

macOS Compatibility Headers¶

The assets/libraries/ directory contains headers missing on macOS:

Header	Purpose
`elf.h`	ELF format definitions
`byteswap.h`	Byte swapping macros
`asm/bitsperlong.h`	Architecture bit width

These are included via HOSTCFLAGS=-I<assets/libraries>.

Adding New Templates¶

Create template in assets/templates/<category>/

Add accessor function in assets/embed.go:

func GetNewTemplate() ([]byte, error) {
    return Templates.ReadFile("templates/category/new.tmpl")
}

Rebuild: task build