Java-使用密码的ProcessBuilder rsync命令失败

Question

I am trying to transfer a file via rsync.

Here is my snippet:

ProcessBuilder builder = new ProcessBuilder("rsync", "-az", "-e", "ssh -q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null -oPubkeyAuthentication=no", username + "@" + host + ":" + filePath, destPath);
Process process = builder.start();
InputStream errorStream = process.getErrorStream();

// Password
OutputStream outputStream = process.getOutputStream();
outputStream.write(password.getBytes(StandardCharsets.UTF_8));

// Wait for execution
int exitValue = process.waitFor();
if (exitValue != 0) {
    String errorMessage = read(errorStream);
    System.out.println(errorMessage);
}

and this is the error message:

rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: unexplained error (code 255) at io.c(226) [Receiver=3.1.0]

I can confirm method arguments (such as password, username, host etc) are non-null and valid. Also I can successfully run the same rsync command using the CLI.

I've found a similar problem here and tried SSH options with or without quotes but it didn't work.

Here is the output of ps aux | grep rsync ps aux | grep rsync while running the program:

emre      8566  0.0  0.0  17396   908 ?        S    18:15   0:00 rsync -az -e ssh -q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null -oPubkeyAuthentication=no user@XXXX:/tmp/dummy-file /tmp/
emre      8568  0.3  0.0  36148  3028 ?        S    18:15   0:00 ssh -q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null -oPubkeyAuthentication=no -l user XXXX rsync --server --sender -logDtprze.iLs . /tmp/dummy-file

What am I missing here? Is this the correct way to use ProcessBuilder ?

Thanks in advance

Answer 1

Rsync doesn't handle authentication by itself, ssh-agent does this instead. Writing password to process output stream is wrong: it doesn't pass password to ssh-agent. Instead you can set environment variable RSYNC_PASSWORD=<password> .