MuntashirAkon/AppManager · warning

Warning: chown failed: %s\n

Error message

Warning: chown failed: %s\n

What it means

After resolving am.jar, chown(exec_jar_path, uid, gid) failed, so the copied jar could not be given the app user's ownership. This is non-fatal — the binary prints a warning and continues, but the app process may later fail to read/execute the jar.

Source

Thrown at app/src/main/cpp/run_server.c:163

    uid_t uid = getuid();
    gid_t gid = getgid();
    printf("Starting %s as %d:%d...\n", SERVER_NAME, uid, gid);

    // Copy am.jar as /data/local/tmp/am.jar
    const char *resolved_am_jar_path = NULL;
    for (int i = 0; i < 4; i++) {
        if (copy_file(am_jar_fallbacks[i], exec_jar_path) == 0) {
            resolved_am_jar_path = am_jar_fallbacks[i];
            break;
        }
    }
    if (resolved_am_jar_path == NULL) {
        fprintf(stderr, "Error! %s could not be found or copied.\n", am_jar_name);
        return 1;
    }
    // Fix ownership
    if (chown(exec_jar_path, uid, gid) != 0) {
        fprintf(stderr, "Warning: chown failed: %s\n", strerror(errno));
        // Although it failed, still proceed
    }

    // Copy main.jar as /data/local/tmp/main.jar
    const char *resolved_main_jar_path = NULL;
    for (int i = 0; i < 4; i++) {
        if (copy_file(main_jar_fallbacks[i], main_jar_path) == 0) {
            resolved_main_jar_path = main_jar_fallbacks[i];
            break;
        }
    }
    if (resolved_main_jar_path == NULL) {
        fprintf(stderr, "Error! %s could not be found or copied.\n", main_jar_name);
        return 1;
    }
    // Fix ownership
    if (chown(main_jar_path, uid, gid) != 0) {
        fprintf(stderr, "Warning: chown failed: %s\n", strerror(errno));

View on GitHub (pinned to 0152f468fc)

Solutions

1. Run the binary as root (su) so chown succeeds
2. Manually verify/fix ownership with adb: chown <uid>:<gid> /data/local/tmp/am.jar
3. Confirm the jar is readable by the target app uid even without chown (chmod 644)
4. Ignore if execution still works — this is a warning, not fatal

Process p = Runtime.getRuntime().exec(new String[]{"su","-c", cmd});
String err = readStream(p.getErrorStream());
if (err.contains("chown failed")) {
    // proceed, but ensure jar is world-readable instead
    exec("chmod 644 " + jarPath);
}

When it happens

Trigger: The process running run_server lacks permission (not root / wrong uid) to chown the file at /data/local/tmp/<am_jar_name>, or the file lives on a filesystem that does not support chown (some emulated/FUSE mounts).

Common situations: Running without root on a non-rooted device; SELinux policy blocking chown on /data/local/tmp; FUSE-backed sdcard paths not supporting ownership changes.

Understand the failure class

Background: Permission denied / not authorized / 403 Forbidden: access-control rejections when the caller lacks the required role, grant, or ownership — this error's family across 18 libraries.

Related errors

• Could not delete the selected backups
• Could not create package staging directory
• Could not create directory ${dataSourceFile}
• Failed to restore ownership info for index ${index}.
• EBADF

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/8aafabae44abbf0b. Report an issue: GitHub.