From 81de538e46c154267c4fb7e87cf6804aed63f3df Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Fri, 3 Feb 2006 14:20:59 +0000 Subject: [PATCH] * Use setsid instead of setpgrp in child processes. This not only creates a new process group but also a new session. New sessions have no controlling tty, so child processes like ssh cannot open /dev/tty (which is bad). --- src/libstore/build.cc | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 123248c17..85c89f2c5 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -276,17 +276,19 @@ void Goal::trace(const format & f) /* Common initialisation performed in child processes. */ void commonChildInit(Pipe & logPipe) { - /* Put the child in a separate process group so that it doesn't - receive terminal signals. */ - if (setpgid(0, 0) == -1) - throw SysError(format("setting process group")); - + /* Put the child in a separate session (and thus a separate + process group) so that it has no controlling terminal (meaning + that e.g. ssh cannot open /dev/tty) and it doesn't receive + terminal signals. */ + if (setsid() == -1) + throw SysError(format("creating a new session")); + /* Dup the write side of the logger pipe into stderr. */ if (dup2(logPipe.writeSide, STDERR_FILENO) == -1) throw SysError("cannot pipe standard error into log file"); logPipe.readSide.close(); - /* Dup stderr to stdin. */ + /* Dup stderr to stdout. */ if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1) throw SysError("cannot dup stderr into stdout");