>>>>> "Xiangfu" == Xiangfu Liu <[email protected]> writes:
> On 12/26/2010 01:43 AM, David Kuehling wrote: >>>>>>> "David" == David Kuehling <[email protected]> writes: >> >>>>>>> "Xiangfu" == Xiangfu Liu <[email protected]> writes: >> >>>> when we run 'ash' 'bash' in gmenu2x it's always give me : /bin/ash >>>> : can't access tty; job control is turned off when start 'ash' >>>> 'bash' >>>> (http://en.qi-hardware.com/wiki/OpenWrt_Software_Image#Image_2010-12-14 >>>> see the * KNOWN ISSUES) >> >>> Ok, after lots of trial and error, I now have a fix that works. It >>> is *ugly*, need to clean it up a bit, but anyways: >> [..] >> >> Turns out there is a much more concise fix for the problem: >> >> --8<-- int pid = setsid(); tcsetpgrp(1, pid); ioctl(1, TIOCSCTTY, >> (char *)1); --8<-- > Hi David > just test your code. it works fine. but the tcsetpgrp(1, pid); it > always return "-1". seems we don't need it. Ok, nice you found that out. > form the manual: > http://pubs.opengroup.org/onlinepubs/009695399/functions/setsid.html > when we run 'setsid', pid have no controlling terminal, so 'tcsetpgrp' > will fail. Hmm. I had a long look through documuentation Linux' rules about when and how processes get (and lose) their controlling terminal. And even now it doesn't really make sense to me :) This is what I looked at: http://www.win.tue.nl/~aeb/linux/lk/lk-10.html > one question about ioctl(1, TIOCSCTTY, (char *)1); the first "1" means > /dev/tty1, right?? what is the meaning of "(char *)1"? It means stdout (the file descriptor, not the stream). As Alan pointed out, we could (and should) replace this with constant STDOUT_FILENO as defined in unistd.h cheers, David -- GnuPG public key: http://user.cs.tu-berlin.de/~dvdkhlng/dk.gpg Fingerprint: B17A DC95 D293 657B 4205 D016 7DEF 5323 C174 7D40
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