|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "flag" |
| 6 | + "fmt" |
| 7 | + "io" |
| 8 | + "net/http" |
| 9 | + "os" |
| 10 | + "os/exec" |
| 11 | + "path/filepath" |
| 12 | + "runtime" |
| 13 | + "time" |
| 14 | + |
| 15 | + "gopkg.in/yaml.v3" |
| 16 | +) |
| 17 | + |
| 18 | +type playbookConfig struct { |
| 19 | + Nixpkgs struct { |
| 20 | + Version string `yaml:"version"` |
| 21 | + Packages []string `yaml:"packages"` |
| 22 | + } `yaml:"nixpkgs"` |
| 23 | +} |
| 24 | + |
| 25 | +func main() { |
| 26 | + var yamlPath string |
| 27 | + var outPath string |
| 28 | + var workDir string |
| 29 | + |
| 30 | + flag.StringVar(&yamlPath, "yaml", "", "Path to YAML with nixpkgs.packages") |
| 31 | + flag.StringVar(&outPath, "out", "toolbox.tar.xz", "Output archive path") |
| 32 | + flag.StringVar(&workDir, "workdir", ".", "Working directory where toolbox/ is created") |
| 33 | + flag.Parse() |
| 34 | + |
| 35 | + if yamlPath == "" { |
| 36 | + fmt.Fprintln(os.Stderr, "error: -yaml path is required") |
| 37 | + os.Exit(2) |
| 38 | + } |
| 39 | + if runtime.GOOS != "linux" { |
| 40 | + fmt.Fprintln(os.Stderr, "error: this utility must run on Linux") |
| 41 | + os.Exit(2) |
| 42 | + } |
| 43 | + |
| 44 | + cfg, err := readYAML(yamlPath) |
| 45 | + if err != nil { |
| 46 | + fatalf("failed to read YAML: %v", err) |
| 47 | + } |
| 48 | + if len(cfg.Nixpkgs.Packages) == 0 { |
| 49 | + fatalf("no nixpkgs.packages listed in %s", yamlPath) |
| 50 | + } |
| 51 | + |
| 52 | + toolboxDir, _ := filepath.Abs(filepath.Join(workDir, "toolbox")) |
| 53 | + _ = exec.Command("chmod", "-R", "u+w", toolboxDir).Run() |
| 54 | + _ = exec.Command("rm", "-rf", toolboxDir).Run() |
| 55 | + |
| 56 | + defer func() { |
| 57 | + _ = exec.Command("chmod", "-R", "u+w", toolboxDir).Run() |
| 58 | + _ = exec.Command("rm", "-rf", toolboxDir).Run() |
| 59 | + }() |
| 60 | + |
| 61 | + if err := nixCopy(toolboxDir, cfg.Nixpkgs.Packages); err != nil { |
| 62 | + fatalf("nix copy failed: %v", err) |
| 63 | + } |
| 64 | + |
| 65 | + if err := fetchAndInstallProot(toolboxDir); err != nil { |
| 66 | + fatalf("failed to install proot: %v", err) |
| 67 | + } |
| 68 | + |
| 69 | + if err := createTarXz(outPath, toolboxDir); err != nil { |
| 70 | + fatalf("failed to create tar.xz: %v", err) |
| 71 | + } |
| 72 | + |
| 73 | + fmt.Printf("created %s\n", outPath) |
| 74 | +} |
| 75 | + |
| 76 | +func readYAML(path string) (*playbookConfig, error) { |
| 77 | + data, err := os.ReadFile(path) |
| 78 | + if err != nil { |
| 79 | + return nil, err |
| 80 | + } |
| 81 | + var cfg playbookConfig |
| 82 | + if err := yaml.Unmarshal(data, &cfg); err != nil { |
| 83 | + return nil, err |
| 84 | + } |
| 85 | + return &cfg, nil |
| 86 | +} |
| 87 | + |
| 88 | +func nixCopy(destDir string, pkgs []string) error { |
| 89 | + if _, err := exec.LookPath("nix"); err != nil { |
| 90 | + return fmt.Errorf("nix not found in PATH: %w", err) |
| 91 | + } |
| 92 | + args := []string{ |
| 93 | + "--extra-experimental-features", "flakes", |
| 94 | + "--extra-experimental-features", "nix-command", |
| 95 | + "copy", |
| 96 | + "--to", destDir, |
| 97 | + } |
| 98 | + for _, p := range pkgs { |
| 99 | + args = append(args, "nixpkgs#"+p) |
| 100 | + } |
| 101 | + cmd := exec.Command("nix", args...) |
| 102 | + cmd.Stdout = os.Stdout |
| 103 | + cmd.Stderr = os.Stderr |
| 104 | + return cmd.Run() |
| 105 | +} |
| 106 | + |
| 107 | +func fetchAndInstallProot(destDir string) error { |
| 108 | + arch := runtime.GOARCH |
| 109 | + var url string |
| 110 | + // Values provided by user; nix base32 style digests |
| 111 | + switch arch { |
| 112 | + case "amd64": |
| 113 | + url = "https://web.archive.org/web/20240412082958if_/http://dl-cdn.alpinelinux.org/alpine/edge/testing/x86_64/proot-static-5.4.0-r0.apk" |
| 114 | + case "arm64": |
| 115 | + url = "https://web.archive.org/web/20240412083320if_/http://dl-cdn.alpinelinux.org/alpine/edge/testing/aarch64/proot-static-5.4.0-r0.apk" |
| 116 | + default: |
| 117 | + return fmt.Errorf("unsupported architecture %s; only amd64 and arm64 are supported", arch) |
| 118 | + } |
| 119 | + |
| 120 | + client := &http.Client{Timeout: 60 * time.Second} |
| 121 | + resp, err := client.Get(url) |
| 122 | + if err != nil { |
| 123 | + return err |
| 124 | + } |
| 125 | + defer resp.Body.Close() |
| 126 | + if resp.StatusCode != http.StatusOK { |
| 127 | + return fmt.Errorf("download failed: %s", resp.Status) |
| 128 | + } |
| 129 | + buf := &bytes.Buffer{} |
| 130 | + if _, err := io.Copy(buf, resp.Body); err != nil { |
| 131 | + return err |
| 132 | + } |
| 133 | + |
| 134 | + if err := extractProotFromAPK(buf.Bytes(), filepath.Join(destDir, "proot")); err != nil { |
| 135 | + return err |
| 136 | + } |
| 137 | + return nil |
| 138 | +} |
| 139 | + |
| 140 | + |
| 141 | + |
| 142 | +func extractProotFromAPK(apk []byte, destPath string) error { |
| 143 | + workDir, err := os.MkdirTemp("", "proot_apk_*") |
| 144 | + if err != nil { |
| 145 | + return err |
| 146 | + } |
| 147 | + defer os.RemoveAll(workDir) |
| 148 | + |
| 149 | + apkPath := filepath.Join(workDir, "proot.apk") |
| 150 | + if err := os.WriteFile(apkPath, apk, 0o644); err != nil { |
| 151 | + return err |
| 152 | + } |
| 153 | + |
| 154 | + gzPath := apkPath + ".tar.gz" |
| 155 | + if err := os.Rename(apkPath, gzPath); err != nil { |
| 156 | + return err |
| 157 | + } |
| 158 | + |
| 159 | + cmd := exec.Command("tar", "-xzf", gzPath, "-C", workDir) |
| 160 | + cmd.Stdout = os.Stdout |
| 161 | + cmd.Stderr = os.Stderr |
| 162 | + if err := cmd.Run(); err != nil { |
| 163 | + return fmt.Errorf("tar extract failed: %w", err) |
| 164 | + } |
| 165 | + |
| 166 | + candidate := filepath.Join(workDir, "usr", "bin", "proot.static") |
| 167 | + if _, err := os.Stat(candidate); err == nil { |
| 168 | + return copyExecutable(candidate, destPath) |
| 169 | + } |
| 170 | + |
| 171 | + var found string |
| 172 | + _ = filepath.WalkDir(workDir, func(p string, d os.DirEntry, _ error) error { |
| 173 | + if d != nil && !d.IsDir() && filepath.Base(p) == "proot.static" { |
| 174 | + found = p |
| 175 | + return io.EOF |
| 176 | + } |
| 177 | + return nil |
| 178 | + }) |
| 179 | + if found == "" { |
| 180 | + return fmt.Errorf("proot.static not found in APK") |
| 181 | + } |
| 182 | + return copyExecutable(found, destPath) |
| 183 | +} |
| 184 | + |
| 185 | +func copyExecutable(src, dst string) error { |
| 186 | + if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil { |
| 187 | + return err |
| 188 | + } |
| 189 | + srcF, err := os.Open(src) |
| 190 | + if err != nil { |
| 191 | + return err |
| 192 | + } |
| 193 | + defer srcF.Close() |
| 194 | + |
| 195 | + dstF, err := os.OpenFile(dst, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o755) |
| 196 | + if err != nil { |
| 197 | + return err |
| 198 | + } |
| 199 | + if _, err := io.Copy(dstF, srcF); err != nil { |
| 200 | + dstF.Close() |
| 201 | + return err |
| 202 | + } |
| 203 | + return dstF.Close() |
| 204 | +} |
| 205 | + |
| 206 | +func createTarXz(outPath string, dir string) error { |
| 207 | + parent := filepath.Dir(dir) |
| 208 | + base := filepath.Base(dir) |
| 209 | + |
| 210 | + cmd := exec.Command("tar", "-I", "xz -e -9 -T0", "-cf", outPath, base) |
| 211 | + cmd.Dir = parent |
| 212 | + cmd.Stdout = os.Stdout |
| 213 | + cmd.Stderr = os.Stderr |
| 214 | + return cmd.Run() |
| 215 | +} |
| 216 | + |
| 217 | +func fatalf(format string, a ...any) { |
| 218 | + fmt.Fprintf(os.Stderr, format+"\n", a...) |
| 219 | + os.Exit(1) |
| 220 | +} |
| 221 | + |
| 222 | + |
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