I'm looking for a way to exec a process (as in, `execve(2)`) and write something to its stdin.
Context: I am writing a tool that does some argument processing and then executes another (arbitrary) program, and passes the processed data to that other program's stdin. The processed data cannot be written to disk because of security constraints, hence using stdin. This does not need to be portable as it will only run on Linux. I can accomplish this with an `exec.Command`, but I would prefer not to because: * my go executable will still appear in the process chain, and ideally it would not (I would rather it be replaced by the new process) * I need the exit code from executing my go tool to be the exit code of the other process that gets executed. With `exec.Command` I need to write custom code to read and return the right exit code from the child; with `execve` this would happen automatically. So the next obvious choice is `syscall.Exec`. This solves the above problems, but there's a new problem: no way that I can see to send data to the new process's stdin. Exec Example: https://play.golang.org/p/HMY8QysTtE8 (Note: I'm using `awk` in this example, but that is just an example. My real code will execute other programs. In the playground you will not see the output from `awk` but if you run locally you will.) So I tried `syscall.ForkExec`, which lets me use a pipe to write data to the new process. But the other program now has a different pid and the exit code is not returned. i.e., it has not replaced my go process---it's being exec'd in the forked process. ForkExec Example: https://play.golang.org/p/ZhoAljhUFGp (Note: I'm using `awk` in this example, but that is just an example. My real code will execute other programs. In the playground you will not see the output from `awk` but if you run locally you will.) Is there a way to accomplish this in go? Normally what I'd do is `fork` a process that would handle writing to a pipe, `dup` the read end of the pipe to stdin and then `exec` to the process I want to run, but `syscall` doesn't have a `Fork`. I could probably use `import "C"` but at that point I would just rather write the tool in C. Thanks for any suggestions! -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/0b245b98-81c7-4eb0-b3a7-61eca2db2a59n%40googlegroups.com.
