Date: Thu, 18 Oct 2007 16:30:00 +0800 From: David Xu <davidxu@FreeBSD.org> To: Artem Kuchin <matrix@itlegion.ru> Cc: freebsd-current@FreeBSD.org Subject: Re: Broken su in current - trying to fix myself, help needed! Message-ID: <47171988.7040706@freebsd.org> In-Reply-To: <00bd01c810ec$10371230$0c00a8c0@Artem>
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Artem Kuchin wrote: > Hello! > > I really not at all good at any kind of system programming > in FreeBSD or Un*x, but since my contacts with last commited > of su could not be establish i decided to look at it myself. > > If you don't know what is the problem i'll describe it shortly: > > if you try to run a very simple perl script: > > #!/usr/bin/perl > $com="/usr/bin/su root -c 'echo heck'"; > system($com); > print "done!\n"; > > it will print heck > > and then > > Suspended (tty output) > > and will hang in memory untill you type > fg > > then you get > > done! > > > I am working in csh, but i tested it in sh - result is > the same. FreeBSD version is 7-PRERELEASE. > > > So, I fetched su v. 1.76 from 6.2-STABLE and compiled it - it works > like a charm. SO, i decided to figure what fails in 1.86. > > There are such like in the default: dection of switch > > child_pgrp = getpgid(child_pid); > if (tcgetpgrp(STDERR_FILENO) == child_pgrp) > tcsetpgrp(STDERR_FILENO, getpgrp()); > > > The problem is here. > getpgid(child_pid) simply fails with errno 3 (process doesn't exist) > and tcgetpgrp(STDERR_FILENO) return 100000 (can it be THAT high? i though > it is only in 0-65535 range). > > The weird thing is that if i just comment out those lines like this > > /* child_pgrp = getpgid(child_pid); > if (tcgetpgrp(STDERR_FILENO) == child_pgrp) */ > tcsetpgrp(STDERR_FILENO, getpgrp()); > > su starts working again just fine. > > Any idea why getpgid fails and why tcgetpgrp return 100000 (always the same > number)? What will brak if i leave these lines commented? > > -- > Regards, > Artem file su.c, line 472 may be incorrect since line 456 is a while loop which only exits if child process is exited. just remove line 472 and 473 to see if problem is fixed. Regards, David Xuhome | help
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