topic Re: Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800) in Operating System - Linux

Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800)

jose_lius_fdez_diaz_new — Thu, 03 May 2007 12:00:36 GMT

Hi,

Given then program below (foo.C):

#include
#include
#include

void sigterm_proc(int s)
{
cout << "sigterm_proc " << s << endl;
}

int main()
{

signal(SIGTERM, sigterm_proc);

sleep(60);
cout << "wake up" << endl;
}

When I compile it with "aCC -lcl k2.c" and send a SIGTERM signal (kill pid) the output is:

sigterm_proc 15
wake up

But if I compile it with "aCC -lcl -lBSD foo.C" the output is:

sigterm_proc 15

and the process doesn't wake up. Is there any bug is libBSD library?

Thanks in advance,
Jose Luis.

Re: Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800)

A. Clay Stephenson — Thu, 03 May 2007 12:47:55 GMT

I am going to assume that your two source files "k2.c" and "foo.C" are identical; if not, your question is meaningless.

I suspect that your seconds example is not quite complete in that the program will terminate and print "wake up" after the sleep terminates.

Without testing, I am assumming that the sleep() function behaves as documented in that any caught signal terminates the sleep as well as its normal SIGALRM behavior. When libBSD is linked in, the sleep function there does not terminate upon the receipt of a caught signal.

You can verify this by using tusc to attach to the two versions but I am all but sure that it is the behavior of the sleep function that changes.

Re: Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800)

Dennis Handly — Thu, 03 May 2007 23:11:32 GMT

Any reason you are adding -lcl to your link line? This is added by default.

Re: Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800)

jose_lius_fdez_diaz_new — Fri, 04 May 2007 02:04:18 GMT

What is useful for the libBSD library? What is does change the standard behavior of sleep?

If I don't use libcl the program runs fine. I don't understand why.

Thanks for your replies.

Regards,
Jose Luis

Re: Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800)

Dennis Handly — Sat, 05 May 2007 01:39:38 GMT

>What is useful for the libBSD library?

I would assume you knew that since you must have some good reason for using it?? If not, junk it ASAP. Looking at some man pages may mention using libBSD.

>If I don't use libcl the program runs fine. I don't understand why.

I don't know either except you have libcl before AND after libBSD and that may cause libcl to use the foreign devil versions in libBSD instead of libc.

Re: Problems with SIGTERM and libBSD (HP-UX B.11.00 U 9000/800)

Dennis Handly — Tue, 08 May 2007 05:17:39 GMT

Adding -lcl makes no difference, it is already there.

tusc shows:
libBSD:
[5134] sigaction(SIGTERM, 0x7f7f0f08, 0x7f7f0f30) ........ = 0
[5134] sigprocmask(SIG_BLOCK, 0x7f7f0ed8, 0x7f7f0ef8) .... = 0
[5134] getitimer(ITIMER_REAL, 0x7f7f0f18) ................ = 0
[5134] time(NULL) ........................................ = 1178618346
[5134] sigtimedwait(0x7f7f0f28, NULL, 0x7f7f0f48) ........ [sleeping]
[5134] Received signal 15, SIGTERM, in sigtimedwait(), [caught], no siginfo
[5134] sigtimedwait(0x7f7f0f28, NULL, 0x7f7f0f48) ........ ERR#4 EINTR
[5134] Received signal 26, SIGCONT, in sigenable(), [SIG_DFL], no siginfo
[5134] write(1, "s i g t e r m _ p r o c 1 5 \n", 16) .. = 16
[5134] sigtimedwait(0x7f7f0f28, NULL, 0x7f7f0f48) ........ [sleeping]

No libBSD:
[5253] sigprocmask(SIG_SETMASK, 0x7f7f0f60, 0x7f7f0f80) .. = 0
[5253] sigprocmask(SIG_SETMASK, 0x7f7f0f80, 0x7f7f0f60) .. = 0
[5253] sigsetreturn(0x7b036fbe, 0x6211988, 1392) ......... = 0
[5253] sigprocmask(SIG_SETMASK, 0x7f7f0f60, 0x7f7f0f80) .. = 0
[5253] sigprocmask(SIG_SETMASK, 0x7f7f0f80, 0x7f7f0f60) .. = 0
[5253] sigvec(SIGTERM, 0x7f7f0ec0, 0x7f7f0ed0) ........... = 0
[5253] sigprocmask(SIG_BLOCK, 0x7f7f0ed8, 0x7f7f0ef8) .... = 0
[5253] getitimer(ITIMER_REAL, 0x7f7f0f18) ................ = 0
[5253] time(NULL) ........................................ = 1178618480
[5253] sigtimedwait(0x7f7f0f28, NULL, 0x7f7f0f48) ........ [sleeping]
[5253] Received signal 15, SIGTERM, in sigtimedwait(), [caught], no siginfo
[5253] sigtimedwait(0x7f7f0f28, NULL, 0x7f7f0f48) ........ ERR#4 EINTR
[5253] Received signal 26, SIGCONT, in sigenable(), [SIG_DFL], no siginfo
[5253] write(1, "s i g t e r m _ p r o c 1 5 \n", 16) .. = 16
[5253] time(NULL) ........................................ = 1178618491
[5253] sigprocmask(SIG_SETMASK, 0x7f7f0ef8, NULL) ........ = 0
[5253] write(1, "w a k e u p \n", 8) ................... = 8
[5253] exit(0) ........................................... WIFEXITED(0)

So libBSD probably changes signal(2) to sigaction(2) and sets SA_RESTART?