java.lang.Process does not fail when running a non-existing binary

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Note: this issue was migrated automatically using bugzilla2github

Original bug ID: BZ#111585
From: @guillerodriguez
Reported version: 0.99

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Comment author: @guillerodriguez

Trying to run a non-existing binary via Runtime.exec or ProcessBuilder.start does not fail. The java.lang.Process object is apparently created successfully, and failure is only reported when Process.waitFor is called, making it impossible to distinguish between "could not execute program" and "the executed program finished with a non-success exit code".

Test code:

Process process = Runtime.getRuntime().exec("dummy");
System.out.println("waitFor: " + process.waitFor());

Output on JDK:

Exception in thread "main" java.io.IOException: Cannot run program "dummy": error=2, No such file or directory
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
    at java.lang.Runtime.exec(Runtime.java:621)
    at java.lang.Runtime.exec(Runtime.java:451)
    at java.lang.Runtime.exec(Runtime.java:348)
    at Run.main(Run.java:6)

Output on JamVM + Classpath:

waitFor: -6

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Comment author: @guillerodriguez

This behaviour is casued by this code in the cpproc_forkAndExec() function, in native/jni/native-lib/cpproc.c:

  [...]
  pid = fork();
  
  switch (pid)
    {
    case 0:
      /* child */   
      [...]

      i = chdir(wd);
      /* FIXME: Handle the return value */
      if (newEnviron == NULL)
	execvp(commandLine[0], commandLine);
      else
	execve(commandLine[0], commandLine, newEnviron);
      
      abort();
      
      break;
    case -1:
      /* error */
      [...]

    default: 
      /* parent */
      [...]
      *out_pid = pid;
      return 0;
    }

The execvp/execve call fails, so the child calls abort. The negative value returned by Process.waitFor means that the child died due to a signal, in this case SIGABRT.