Date: Wed, 17 Oct 2007 22:32:16 +0400 From: "Artem Kuchin" <matrix@itlegion.ru> To: <freebsd-current@freebsd.org> Subject: Broken su in current - trying to fix myself, help needed! Message-ID: <00bd01c810ec$10371230$0c00a8c0@Artem>
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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
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