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// Eagle Mode configuration wrapper that recreates the required directory
// structure for Eagle Mode based on the output of depot.tools.eaglemode.etcDir
//
// This will replace *all* symlinks in the Eagle Mode configuration directory,
// but it will not touch actual files. Missing folders will be created.
package main
import (
"flag"
"fmt"
"io/fs"
"log"
"os"
"os/user"
"path"
"path/filepath"
"strings"
)
func configDir() (string, error) {
v := os.Getenv("EM_USER_CONFIG_DIR")
if v != "" {
return v, nil
}
usr, err := user.Current()
if err != nil {
return "", fmt.Errorf("failed to get current user: %w", err)
}
return path.Join(usr.HomeDir, ".eaglemode"), nil
}
// cleanupConfig removes *all* existing symlinks in the configuration which do
// not point into the right Nix store path.
func cleanupConfig(conf string, dir string) (map[string]bool, error) {
// In case of first launch, we might have to create the directory.
_ = os.MkdirAll(dir, 0755)
c := 0
currentFiles := map[string]bool{}
walker := func(p string, d fs.DirEntry, e error) error {
if e != nil {
return fmt.Errorf("could not walk %s in config directory: %w", p, e)
}
if d.Type()&fs.ModeSymlink != 0 {
target, err := os.Readlink(p)
if err != nil {
return fmt.Errorf("could not read link for %s: %w", p, err)
}
if !strings.HasPrefix(target, conf) {
err = os.Remove(p)
c++
if err != nil {
return fmt.Errorf("could not remove stale link %q: %w", p, err)
}
log.Printf("removed stale symlink %q", p)
} else {
currentFiles[p] = false
}
}
if d.Type().IsRegular() {
currentFiles[p] = true
}
return nil
}
err := filepath.WalkDir(dir, walker)
if err != nil {
return nil, err
}
if c > 0 {
log.Printf("removed %v stale symlinks", c)
}
return currentFiles, nil
}
// linkConfig traverses the given Eagle Mode configuration and links everything
// to the expected location in the user's configuration directory.
//
// If the user placed actual files in the configuration directory at paths that
// would be overwritten, they will not be touched.
func linkConfig(conf string, dir string, existing map[string]bool) error {
walker := func(p string, d fs.DirEntry, e error) error {
if e != nil {
return fmt.Errorf("could not walk %s in config directory: %w", p, e)
}
target := path.Join(dir, strings.TrimPrefix(p, conf))
if d.Type().IsDir() {
err := os.MkdirAll(target, 0755)
if err != nil {
return fmt.Errorf("could not create directory %q: %w", target, err)
}
return nil
}
if shadow, exists := existing[target]; exists {
if shadow {
log.Printf("WARN: file %q already exists and shadows a file from configuration", target)
}
return nil
}
err := os.Symlink(p, target)
if err != nil {
return fmt.Errorf("failed to link %q: %w", target, err)
}
return nil
}
return filepath.WalkDir(conf, walker)
}
func main() {
emConfig := flag.String("em-config", "", "path to em-config dir")
flag.Parse()
log.Println("verifying current Eagle Mode configuration")
if *emConfig == "" {
log.Fatalf("Eagle Mode configuration must be given")
}
if !strings.HasPrefix(*emConfig, "/nix/store/") {
log.Fatalf("Eagle Mode configuration must be in Nix store")
}
dir, err := configDir()
if err != nil {
log.Fatalf("could not determine Eagle Mode config dir: %v", err)
}
currentFiles, err := cleanupConfig(*emConfig, dir)
if err != nil {
log.Fatalf("failed to remove stale symlinks: %v", err)
}
err = linkConfig(*emConfig, dir, currentFiles)
if err != nil {
log.Fatalf("failed to link new configuration: %v", err)
}
log.Println("Eagle Mode configuration updated")
}
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