test/testcases/sysv/sysvsem/semtest.c

   1 /*-
   2  * Copyright (c) 1999 The NetBSD Foundation, Inc.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to The NetBSD Foundation
   6  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
   7  * NASA Ames Research Center.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the NetBSD
  20  *      Foundation, Inc. and its contributors.
  21  * 4. Neither the name of The NetBSD Foundation nor the names of its
  22  *    contributors may be used to endorse or promote products derived
  23  *    from this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35  * POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Obtained from: $NetBSD: semtest.c,v 1.4 2002/07/20 08:36:25 grant Exp $
  38  */
  39
  40 /*
  41  * Test the SVID-compatible Semaphore facility.
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/ipc.h>
  46 #include <sys/sem.h>
  47 #include <sys/wait.h>
  48
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <signal.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <time.h>
  56 #include <unistd.h>
  57
  58 void    print_semid_ds (struct semid_ds *, mode_t);
  59 void    sigsys_handler (int);
  60 void    sigchld_handler(int);
  61 void    cleanup (void);
  62 void    waiter (void);
  63 void    usage (void);
  64
  65 int     sender_semid = -1;
  66 pid_t   child_pid;
  67 int     child_count;
  68 int     signal_was_sigchld;
  69
  70 key_t   semkey;
  71
  72 /*
  73  * This is the original semun union used by the sysvsem utility.
  74  * It is deliberately kept here under #if 0'ed condition for future
  75  * reference. PLEASE DO NOT REMOVE.  The {SET,GET}ALL in DragonFly
  76  * are signed values, so the default version in sys/sem.h suffices.
  77  */
  78 #if 0
  79 union semun {
  80         int     val;            /* value for SETVAL */
  81         struct  semid_ds *buf;  /* buffer for IPC_{STAT,SET} */
  82         u_short *array;         /* array for GETALL & SETALL */
  83 };
  84 #endif
  85
  86 int
  87 main(int argc, char *argv[])
  88 {
  89         struct sigaction sa;
  90         union semun sun;
  91         struct semid_ds s_ds;
  92         sigset_t sigmask;
  93         int i;
  94
  95         if (argc != 2)
  96                 usage();
  97
  98         /*
  99          * Install a SIGSYS handler so that we can exit gracefully if
 100          * System V Semaphore support isn't in the kernel.
 101          */
 102         sa.sa_handler = sigsys_handler;
 103         sigemptyset(&sa.sa_mask);
 104         sa.sa_flags = 0;
 105         if (sigaction(SIGSYS, &sa, NULL) == -1)
 106                 err(1, "sigaction SIGSYS");
 107
 108         /*
 109          * Install and SIGCHLD handler to deal with all possible exit
 110          * conditions of the receiver.
 111          */
 112         sa.sa_handler = sigchld_handler;
 113         sigemptyset(&sa.sa_mask);
 114         sa.sa_flags = 0;
 115         if (sigaction(SIGCHLD, &sa, NULL) == -1)
 116                 err(1, "sigaction SIGCHLD");
 117
 118         semkey = ftok(argv[1], 4160);
 119
 120         /*
 121          * Initialize child_pid to ourselves to that the cleanup function
 122          * works before we create the receiver.
 123          */
 124         child_pid = getpid();
 125
 126         /*
 127          * Make sure that when the sender exits, the message queue is
 128          * removed.
 129          */
 130         if (atexit(cleanup) == -1)
 131                 err(1, "atexit");
 132
 133         if ((sender_semid = semget(semkey, 1, IPC_CREAT | 0640)) == -1)
 134                 err(1, "semget");
 135
 136
 137         sun.buf = &s_ds;
 138         if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
 139                 err(1, "semctl IPC_STAT");
 140
 141         print_semid_ds(&s_ds, 0640);
 142
 143         s_ds.sem_perm.mode = (s_ds.sem_perm.mode & ~0777) | 0600;
 144
 145         sun.buf = &s_ds;
 146         if (semctl(sender_semid, 0, IPC_SET, sun) == -1)
 147                 err(1, "semctl IPC_SET");
 148
 149         memset(&s_ds, 0, sizeof(s_ds));
 150
 151         sun.buf = &s_ds;
 152         if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
 153                 err(1, "semctl IPC_STAT");
 154
 155         if ((s_ds.sem_perm.mode & 0777) != 0600)
 156                 err(1, "IPC_SET of mode didn't hold");
 157
 158         print_semid_ds(&s_ds, 0600);
 159
 160         for (child_count = 0; child_count < 5; child_count++) {
 161                 switch ((child_pid = fork())) {
 162                 case -1:
 163                         err(1, "fork");
 164                         /* NOTREACHED */
 165
 166                 case 0:
 167                         waiter();
 168                         break;
 169
 170                 default:
 171                         break;
 172                 }
 173         }
 174
 175         /*
 176          * Wait for all of the waiters to be attempting to acquire the
 177          * semaphore.
 178          */
 179         for (;;) {
 180                 i = semctl(sender_semid, 0, GETNCNT);
 181                 if (i == -1)
 182                         err(1, "semctl GETNCNT");
 183                 if (i == 5)
 184                         break;
 185         }
 186
 187         /*
 188          * Now set the thundering herd in motion by initializing the
 189          * semaphore to the value 1.
 190          */
 191         sun.val = 1;
 192         if (semctl(sender_semid, 0, SETVAL, sun) == -1)
 193                 err(1, "sender: semctl SETVAL to 1");
 194
 195         /*
 196          * Suspend forever; when we get SIGCHLD, the handler will exit.
 197          */
 198         sigemptyset(&sigmask);
 199         for (;;) {
 200                 (void) sigsuspend(&sigmask);
 201                 if (signal_was_sigchld)
 202                         signal_was_sigchld = 0;
 203                 else
 204                         break;
 205         }
 206
 207         /*
 208          * ...and any other signal is an unexpected error.
 209          */
 210         errx(1, "sender: received unexpected signal");
 211 }
 212
 213 void
 214 sigsys_handler(int signo)
 215 {
 216
 217         errx(1, "System V Semaphore support is not present in the kernel");
 218 }
 219
 220 void
 221 sigchld_handler(int signo)
 222 {
 223         union semun sun;
 224         struct semid_ds s_ds;
 225         int cstatus;
 226
 227         /*
 228          * Reap the child; if it exited successfully, then we're on the
 229          * right track!
 230          */
 231         if (wait(&cstatus) == -1)
 232                 err(1, "wait");
 233
 234         if (WIFEXITED(cstatus) == 0)
 235                 errx(1, "receiver exited abnormally");
 236
 237         if (WEXITSTATUS(cstatus) != 0)
 238                 errx(1, "receiver exited with status %d",
 239                     WEXITSTATUS(cstatus));
 240
 241         /*
 242          * If we get here, the child has exited normally, and we should
 243          * decrement the child count.  If the child_count reaches 0, we
 244          * should exit.
 245          */
 246
 247         sun.buf = &s_ds;
 248         if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
 249                 err(1, "semctl IPC_STAT");
 250
 251         print_semid_ds(&s_ds, 0600);
 252
 253         if (--child_count != 0) {
 254                 signal_was_sigchld = 1;
 255                 return;
 256         }
 257
 258         exit(0);
 259 }
 260
 261 void
 262 cleanup()
 263 {
 264
 265         /*
 266          * If we're the sender, and it exists, remove the message queue.
 267          */
 268         if (child_pid != 0 && sender_semid != -1) {
 269                 if (semctl(sender_semid, 0, IPC_RMID) == -1)
 270                         warn("semctl IPC_RMID");
 271         }
 272 }
 273
 274 void
 275 print_semid_ds(struct semid_ds *sp, mode_t mode)
 276 {
 277         uid_t uid = geteuid();
 278         gid_t gid = getegid();
 279
 280         printf("PERM: uid %d, gid %d, cuid %d, cgid %d, mode 0%o\n",
 281             sp->sem_perm.uid, sp->sem_perm.gid,
 282             sp->sem_perm.cuid, sp->sem_perm.cgid,
 283             sp->sem_perm.mode & 0777);
 284
 285         printf("nsems %u\n", sp->sem_nsems);
 286
 287         printf("otime: %s", ctime(&sp->sem_otime));
 288         printf("ctime: %s", ctime(&sp->sem_ctime));
 289
 290         /*
 291          * Sanity check a few things.
 292          */
 293
 294         if (sp->sem_perm.uid != uid || sp->sem_perm.cuid != uid)
 295                 errx(1, "uid mismatch");
 296
 297         if (sp->sem_perm.gid != gid || sp->sem_perm.cgid != gid)
 298                 errx(1, "gid mismatch");
 299
 300         if ((sp->sem_perm.mode & 0777) != mode)
 301                 errx(1, "mode mismatch %o != %o",
 302                     (sp->sem_perm.mode & 0777), mode);
 303 }
 304
 305 void
 306 usage()
 307 {
 308
 309         fprintf(stderr, "usage: %s keypath\n", getprogname());
 310         exit(1);
 311 }
 312
 313 void
 314 waiter()
 315 {
 316         struct sembuf s;
 317         int semid;
 318
 319         if ((semid = semget(semkey, 1, 0)) == -1)
 320                 err(1, "waiter: semget");
 321
 322         /*
 323          * Attempt to acquire the semaphore.
 324          */
 325         s.sem_num = 0;
 326         s.sem_op = -1;
 327         s.sem_flg = SEM_UNDO;
 328
 329         if (semop(semid, &s, 1) == -1)
 330                 err(1, "waiter: semop -1");
 331
 332         printf("WOO!  GOT THE SEMAPHORE!\n");
 333         sleep(1);
 334
 335         /*
 336          * Release the semaphore and exit.
 337          */
 338         s.sem_num = 0;
 339         s.sem_op = 1;
 340         s.sem_flg = SEM_UNDO;
 341
 342         if (semop(semid, &s, 1) == -1)
 343                 err(1, "waiter: semop +1");
 344
 345         exit(0);
 346 }