Use pipe instead of 'sh -c' to spawn subprocesses #2580
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Filling the whole command into 'sh -c' may hit length limit of single argument. For non-console subprocesses, use pipe to invoke sh instead.
| Fatal("posix_spawn: %s", strerror(err)); | ||
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| if (!use_console_) { | ||
| ssize_t written = write(input_pipe[1], command.c_str(), command.size()); |
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Does that work for large commands?
Most systems use a default pipe buffer size of 64 kiB, some even smaller (see https://github.com/afborchert/pipebuf) so this write() call will block infinitely if command.size() is larger than that (and the bug referenced by this PR talks about command sizes of 128 kiB).
Linux has fcntl(F_SETPIPE_SZ) to change that the pipe buffer size, but I am not aware of similar features on other systems. Even the Linux pipe manpage tsates that applications should not rely on a specific capacity.
It might be more portable and simple to write long commands to a file that is passed as the first argument to the shell instead. And that would also work for console processes too.
Filling the whole command into 'sh -c' may hit length limit of single argument. For non-console subprocesses, use pipe to invoke sh instead.
Fixes #1261