[TUHS] Does this mean Linux is now "officially branded UNIX"?

[Joerg Schilling]

Nemo <cym224 at gmail.com> wrote:

> On 13 March 2017 at 06:15, Joerg Schilling <schily at schily.net> wrote (in part):
> > Given that there have been many problems last time, there was a collaboration
> > between the Linux people and the OpenGroup:
> >
> >         http://www.opengroup.org/personal/ajosey/tr20-08-2005.txt
> >
> > I would guess that this company dod modify software inorder to become compliant.
>
> As they note (http://developer.huawei.com/ict/en/site-euleros ):
> Derived from the source-code for the CentOS distribution.  In due
> course, I may try it.  If this actually works back to most
> distributions, it *may* one day become possible to actually have
> Linux-distro-derived code compile on Unix systems.

In case people write POSIX compliant code...

BTW: passing the POSIX certification does not verify that the system is POSIX 
compliant.

The Linux kernel does e.g. not correctly implement the waitid() syscall and the 
POSIX validation test suite does not yet check for the deviation.

On a real POSIX system, the following test program passes, but this currently 
only applies to Solaris, SCO UnixWare, recent FreeBSD and recent NetBSD:

/*--------------------------------------------------------------------------*/
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <stdio.h>
/*
 * Non-standard compliant platforms may need
 * #include <signal.h> or something similar
 * in addition to the include files above.
 */

extern	void	handler(int sig, siginfo_t *sip, void *context);
extern	void	dosig(void);

pid_t		cpid;

int
main()
{
	siginfo_t	si;
	pid_t		pid;
	int		ret;

	dosig();
	if ((pid = fork()) < 0)
		exit(1);
	cpid = pid;
	if (pid == 0) {
		_exit(1234567890);
	}
	ret = waitid(P_PID, pid, &si, WEXITED);
	printf("                ret: %d si_pid: %ld si_status: %d si_code: %d\n",
		ret,
		(long) si.si_pid, si.si_status, si.si_code);
	if (pid != si.si_pid)
		printf("si_pid in struct siginfo should be %ld but is %ld\n",
			(long) pid, (long) si.si_pid);
	if (si.si_status != 1234567890)
		printf("si_status in struct siginfo should be %d (0x%x) but is %d (0x%x)\n",
			1234567890, 1234567890, si.si_status, si.si_status);
	if (si.si_code != CLD_EXITED)
		printf("si_code in struct siginfo should be %d (0x%x) but is %d (0x%x)\n",
			CLD_EXITED,  CLD_EXITED, si.si_code, si.si_code);
	if (CLD_EXITED != 1)
		printf("CLD_EXITED is %d on this platform\n", CLD_EXITED);
	return (0);
}

/*
 * Include it here to allow to verify that #include <sys/wait.h>
 * makes siginfo_t available
 */
#include <signal.h>

void
handler(int sig, siginfo_t *sip, void *context)
{
	printf("received SIGCHLD (%d), si_pid: %ld si_status: %d si_code: %d\n",
		sig, (long) sip->si_pid, sip->si_status, sip->si_code);

	if (sip->si_pid != cpid)
		printf("SIGCHLD: si_pid in struct siginfo should be %ld but is %ld\n",
			(long) cpid, (long) sip->si_pid);

	if (sip->si_status != 1234567890)
		printf("SIGCHLD: si_status in struct siginfo should be %d (0x%x) but is %d (0x%x)\n",
			1234567890, 1234567890, sip->si_status, sip->si_status);

	if (sip->si_code != CLD_EXITED)
		printf("SIGCHLD: si_code in struct siginfo should be %d (0x%x) but is %d (0x%x)\n",
			CLD_EXITED,  CLD_EXITED, sip->si_code, sip->si_code);
}

void
dosig()
{
	struct sigaction sa;

	sa.sa_sigaction = handler;
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = SA_RESTART|SA_SIGINFO;

	sigaction(SIGCHLD, &sa, NULL);
}
/*--------------------------------------------------------------------------*/

On Solaris, this prints something like:

received SIGCHLD (18), si_pid: 11860 si_status: 1234567890 si_code: 1
                ret: 0 si_pid: 11860 si_status: 1234567890 si_code: 1

On Linux, it prints something like:

received SIGCHLD (17), si_pid: 5434 si_status: 210 si_code: 1
SIGCHLD: si_status in struct siginfo should be 1234567890 (0x499602d2) but is 210 (0xd2)
                ret: 0 si_pid: 5434 si_status: 210 si_code: 1
si_status in struct siginfo should be 1234567890 (0x499602d2) but is 210 (0xd2)

Jörg

-- 
 EMail:joerg at schily.net                  (home) Jörg Schilling D-13353 Berlin
       joerg.schilling at fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
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