ipc/lib/libipc.c

/*
 *
 *   Copyright (c) International Business Machines  Corp., 2001
 *
 *   This program is free software;  you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 * NAME
 *	libmsg.c
 *
 * DESCRIPTION
 *	common routines for the IPC system call tests.
 *
 *	The library contains the following routines:
 *
 *	getipckey()
 *	rm_queue()
 *	init_buf()
 *	rm_sema()
 *	check_root()
 *	getuserid()
 *	rm_shm()
 */

#define LIBIPC
#include "ipcmsg.h"
#include "ipcsem.h"

#include <pwd.h>
#include <sys/timeb.h>
#include <sys/ipc.h>
#include <sys/shm.h>

/*
 * getipckey() - generates and returns a message key used by the "get"
 *		 calls to create an IPC resource.
 */
key_t getipckey()
{
	const char a = 'a';
	int ascii_a = (int)a;
	char *curdir = NULL;
	size_t size = 0;
	key_t ipc_key;
	int proj_id;
	static int count = 0;

	if (NULL == (curdir = getcwd(curdir, size))) {
		tst_brkm(TBROK, cleanup, "Can't get current directory "
			 "in getipckey()");
	}

	/*
	 * Get a Sys V IPC key
	 *
	 * ftok() requires a character as a second argument.  This is
	 * refered to as a "project identifier" in the man page.
	 */
	proj_id = count % 26 + ascii_a;
	count++;

	if ((ipc_key = ftok(curdir, proj_id)) == -1) {
		tst_brkm(TBROK, cleanup, "Can't get msgkey from ftok()");
	}

	return (ipc_key);
}

/*
 * rm_queue() - removes a message queue.
 */
void rm_queue(int queue_id)
{
	if (queue_id == -1) {	/* no queue to remove */
		return;
	}

	if (msgctl(queue_id, IPC_RMID, NULL) == -1) {
		tst_resm(TINFO, "WARNING: message queue deletion failed.");
		tst_resm(TINFO, "This could lead to IPC resource problems.");
		tst_resm(TINFO, "id = %d", queue_id);
	}
}

/*
 * init_buf() - initialize the message buffer with some text and a type.
 */
void init_buf(MSGBUF * m_buf, int type, int size)
{
	int i;
	int ascii_a = (int)'a';	/* the ascii value for 'a' */

	/* this fills the message with a repeating alphabet string */
	for (i = 0; i < size; i++) {
		m_buf->mtext[i] = ascii_a + (i % 26);
	}

	/* terminate the message */
	m_buf->mtext[i] = '\0';

	/* if the type isn't valid, set it to 1 */
	if (type < 1) {
		m_buf->mtype = 1;
	} else {
		m_buf->mtype = type;
	}
}

/*
 * rm_sema() - removes a semaphore.
 */
void rm_sema(int sem_id)
{
	union semun arr;

	if (sem_id == -1) {	/* no semaphore to remove */
		return;
	}

	if (semctl(sem_id, 0, IPC_RMID, arr) == -1) {
		tst_resm(TINFO, "WARNING: semaphore deletion failed.");
		tst_resm(TINFO, "This could lead to IPC resource problems.");
		tst_resm(TINFO, "id = %d", sem_id);
	}
}

/*
 * check_root() - make sure the process ID is root
 */
void check_root()
{
	if (geteuid() != 0) {
		tst_brkm(TBROK, cleanup, "test must be run as root");
	}
}

/*
 * getuserid() - return the integer value for the "user" id
 */
int getuserid(char *user)
{
	struct passwd *ent;

	/* allocate some space for the passwd struct */
	if ((ent = (struct passwd *)malloc(sizeof(struct passwd))) == NULL) {
		tst_brkm(TBROK, cleanup, "couldn't allocate space for passwd"
			 " structure");
	}

	/* get the uid value for the user */
	if ((ent = getpwnam(user)) == NULL) {
		tst_brkm(TBROK, cleanup, "Couldn't get password entry for %s",
			 user);
	}

	return (ent->pw_uid);
}

/*
 * rm_shm() - removes a shared memory segment.
 */
void rm_shm(int shm_id)
{
	if (shm_id == -1) {	/* no segment to remove */
		return;
	}

	/*
	 * check for # of attaches ?
	 */

	if (shmctl(shm_id, IPC_RMID, NULL) == -1) {
		tst_resm(TINFO, "WARNING: shared memory deletion failed.");
		tst_resm(TINFO, "This could lead to IPC resource problems.");
		tst_resm(TINFO, "id = %d", shm_id);
	}
}

#define BUFSIZE 512

/*
 * Get the number of message queues already in use
 */
int get_used_msgqueues()
{
	FILE *f;
	int used_queues;
	char buff[BUFSIZE];

	f = popen("ipcs -q", "r");
	if (!f) {
		tst_resm(TBROK, "Could not run 'ipcs' to calculate used "
			 "message queues");
		tst_exit();
	}
	/* FIXME: Start at -4 because ipcs prints four lines of header */
	for (used_queues = -4; fgets(buff, BUFSIZE, f); used_queues++) ;
	pclose(f);
	if (used_queues < 0) {
		tst_resm(TBROK, "Could not read output of 'ipcs' to "
			 "calculate used message queues");
		tst_exit();
	}
	return used_queues;
}

/*
 * Get the max number of message queues allowed on system
 */
int get_max_msgqueues()
{
	FILE *f;
	char buff[BUFSIZE];

	/* Get the max number of message queues allowed on system */
	f = fopen("/proc/sys/kernel/msgmni", "r");
	if (!f) {
		tst_resm(TBROK, "Could not open /proc/sys/kernel/msgmni");
		return -1;
	}
	if (!fgets(buff, BUFSIZE, f)) {
		fclose(f);
		tst_resm(TBROK, "Could not read /proc/sys/kernel/msgmni");
		return -1;
	}
	fclose(f);
	return atoi(buff);
}