145 lines
3.5 KiB
C
145 lines
3.5 KiB
C
/*
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* eventfd-sem by Davide Libenzi (Simple test for eventfd sempahore)
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* Copyright (C) 2009 Davide Libenzi
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Davide Libenzi <davidel@xmailserver.org>
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* Reference: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=bcd0b235bf3808dec5115c381cd55568f63b85f0
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* Reference: http://www.xmailserver.org/eventfd-sem.c
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* eventfd: testing improved support for semaphore-like behavior in linux-2.6.30
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*
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*/
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#include <sys/types.h>
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#include <sys/syscall.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <inttypes.h>
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#include "test.h"
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#include "lapi/syscalls.h"
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char *TCID = "eventfd2_03";
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int TST_TOTAL = 1;
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#ifndef EFD_SEMLIKE
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#define EFD_SEMLIKE (1 << 0)
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#endif
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/* Dummy function as syscall from linux_syscall_numbers.h uses cleanup(). */
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void cleanup(void)
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{
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}
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static int eventfd2(int count, int flags)
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{
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return ltp_syscall(__NR_eventfd2, count, flags);
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}
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static void xsem_wait(int fd)
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{
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u_int64_t cntr;
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if (read(fd, &cntr, sizeof(cntr)) != sizeof(cntr)) {
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perror("reading eventfd");
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exit(1);
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}
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fprintf(stdout, "[%u] wait completed on %d: count=%" PRIu64 "\n",
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getpid(), fd, cntr);
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}
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static void xsem_post(int fd, int count)
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{
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u_int64_t cntr = count;
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if (write(fd, &cntr, sizeof(cntr)) != sizeof(cntr)) {
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perror("writing eventfd");
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exit(1);
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}
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}
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static void sem_player(int fd1, int fd2)
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{
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fprintf(stdout, "[%u] posting 1 on %d\n", getpid(), fd1);
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xsem_post(fd1, 1);
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fprintf(stdout, "[%u] waiting on %d\n", getpid(), fd2);
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xsem_wait(fd2);
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fprintf(stdout, "[%u] posting 1 on %d\n", getpid(), fd1);
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xsem_post(fd1, 1);
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fprintf(stdout, "[%u] waiting on %d\n", getpid(), fd2);
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xsem_wait(fd2);
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fprintf(stdout, "[%u] posting 5 on %d\n", getpid(), fd1);
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xsem_post(fd1, 5);
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fprintf(stdout, "[%u] waiting 5 times on %d\n", getpid(), fd2);
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xsem_wait(fd2);
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xsem_wait(fd2);
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xsem_wait(fd2);
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xsem_wait(fd2);
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xsem_wait(fd2);
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}
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static void usage(char const *prg)
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{
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fprintf(stderr, "use: %s [-h]\n", prg);
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}
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int main(int argc, char **argv)
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{
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int c, fd1, fd2, status;
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pid_t cpid_poster, cpid_waiter;
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while ((c = getopt(argc, argv, "h")) != -1) {
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switch (c) {
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default:
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usage(argv[0]);
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return 1;
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}
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}
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if ((tst_kvercmp(2, 6, 27)) < 0) {
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tst_brkm(TCONF,
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NULL,
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"This test can only run on kernels that are 2.6.27 and higher");
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}
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if ((fd1 = eventfd2(0, EFD_SEMLIKE)) == -1 ||
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(fd2 = eventfd2(0, EFD_SEMLIKE)) == -1) {
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perror("eventfd2");
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return 1;
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}
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if ((cpid_poster = fork()) == 0) {
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sem_player(fd1, fd2);
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exit(0);
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}
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if ((cpid_waiter = fork()) == 0) {
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sem_player(fd2, fd1);
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exit(0);
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}
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waitpid(cpid_poster, &status, 0);
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waitpid(cpid_waiter, &status, 0);
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tst_exit();
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}
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