tcsetpgrp() causes the shell "bsh" to hang infinitely while trying to set tty process group

[schily]

bsh forks and the child process calls tcsetpgrp() in order to set the TTY process group of the child to the child process. This is needed in order to redirect signals only to the child.

after bsh calls tcsetpgrp(), tcsetpgrp() calls ioctl() and hangs inside the ioctl.

Workaround: edit the Makefile for bsh and comment out the line with -DJOBCONTROL

Note that bsh worked without problems on Zeta.

bsh is inside the schily source consolidation at:

​ftp://ftp.berlios.de/pub/schily/schily-dist/preliminary-2.tar.bz2

The named file is the first version that was ported to Haiku

[simonsouth]

Don't send SIGTTOU if the calling thread is blocking it

[simonsouth]

I've added a patch that should fix this problem.

When a member of a background process group tries to change the foreground process group of its controlling terminal, ​POSIX says SIGTTOU should be sent unless the process is ignoring it or the calling thread is blocking it. The existing code checked the former case but not the latter, which meant the calling thread could get stuck in a loop while the system call was continually restarted.

[simonsouth]

Short program that demonstrates the problem and the fix

[simonsouth]

I've also added a program that demonstrates the problem. Without the patch applied, the program will terminate normally when invoked directly but loop forever when invoked using either strace or the debugger (as it moves itself to a background process group). With the patch applied the program will terminate normally in both cases.

[jessicah]

waddlesplash, looks good to merge to me :)

[waddlesplash]

Appplied in hrev49672. Thanks!