commit cbed6ff8430ee7f7d1002965ebf784628735c234 Author: Alexander Færøy ahf@torproject.org Date: Thu Oct 17 16:47:04 2019 +0200

Ensure that the exit callback is called if CreateProcessA() fails on Windows.

This patch fixes an issue where the exit handler is not called for the given process_t in case CreateProcessA() fails. This could, for example, happen if the user tries to execute a binary that does not exist.

See: https://bugs.torproject.org/31810 --- src/lib/process/process_win32.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)

diff --git a/src/lib/process/process_win32.c b/src/lib/process/process_win32.c index ddbe76bfd..1b1de6ad5 100644 --- a/src/lib/process/process_win32.c +++ b/src/lib/process/process_win32.c @@ -234,6 +234,24 @@ process_win32_exec(process_t *process) CloseHandle(stdin_pipe_read); CloseHandle(stdin_pipe_write);

+ /* In the Unix backend, we do not get an error in the Tor process when a + * child process fails to spawn its target executable since we need to + * first do the fork() call in the Tor process and then the child process + * is responsible for doing the call to execve(). + * + * This means that the user of the process_exec() API must check for + * whether it returns PROCESS_STATUS_ERROR, which will rarely happen on + * Unix, but will happen for error cases on Windows where it does not + * happen on Unix. For example: when the target executable does not exist + * on the file system. + * + * To have somewhat feature compatibility between the Unix and the Windows + * backend, we here notify the process_t owner that the process have exited + * (even though it never managed to run) to ensure that the exit callback + * is executed. + */ + process_notify_event_exit(process, 0); + return PROCESS_STATUS_ERROR; }