Hi Peter, On Wed, Feb 18, 2015 at 10:40:10AM -0500, Peter Hurley wrote: > The child is not receiving SIGHUP because /dev/ttyS0 was not set as the > controlling terminal by ioctl(TIOCSCTTY), which is failing (probably > with errno == EPERM). You need to check the return value and errno. > > To set the controlling tty, the calling process must be a session leader; > ie., have called setsid() before ioctl(TIOCSCTTY). Check the return value > for that too. > > FWIW, the idiom for starting a session leader is for the parent to > fork a child and exit and for the child to become the session leader with > setsid() and establish its controlling tty either with ioctl(TIOCSCTTY) > or simply opening the first tty. > > The reason for this idiom is that setsid() will fail for an existing > group leader (because otherwise a group leader could abandon existing > members of its process group, leaving them without a group leader in > a different session). > > I highly recommend Ch 34 of Michael Kerrisk's book, "The Linux Programming > Interface", especially if this is not a toy project.
Actually wrote this trying to reproduce a problem a customer is seeing in a commercial application, but clearly I need to read it. Specifically about the console behavior, would you recommend the same book? Every time I need details like this I fail to find any reference online. Thanks for your help -- Aristeu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
