tools/regression/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  * $DragonFly: src/tools/regression/sysvsem/semtest.c,v 1.1 2003/10/18 12:13:01 hmp Exp $
  39  */
  40
  41 /*
  42  * Test the SVID-compatible Semaphore facility.
  43  */
  44
  45 #include <sys/param.h>
  46 #include <sys/ipc.h>
  47 #include <sys/sem.h>
  48 #include <sys/wait.h>
  49
  50 #include <err.h>
  51 #include <errno.h>
  52 #include <signal.h>
  53 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <time.h>
  57 #include <unistd.h>
  58
  59 int     main (int, char *[]);
  60 void    print_semid_ds (struct semid_ds *, mode_t);
  61 void    sigsys_handler (int);
  62 void    sigchld_handler(int);
  63 void    cleanup (void);
  64 void    waiter (void);
  65 void    usage (void);
  66
  67 int     sender_semid = -1;
  68 pid_t   child_pid;
  69 int     child_count;
  70 int     signal_was_sigchld;
  71
  72 key_t   semkey;
  73
  74 /*
  75  * This is the original semun union used by the sysvsem utility.
  76  * It is deliberately kept here under #if 0'ed condition for future
  77  * reference. PLEASE DO NOT REMOVE.  The {SET,GET}ALL in DragonFly
  78  * are signed values, so the default version in sys/sem.h suffices.
  79  */
  80 #if 0
  81 union semun {
  82         int     val;            /* value for SETVAL */
  83         struct  semid_ds *buf;  /* buffer for IPC_{STAT,SET} */
  84         u_short *array;         /* array for GETALL & SETALL */
  85 };
  86 #endif
  87
  88 int
  89 main(int argc, char *argv[])
  90 {
  91         struct sigaction sa;
  92         union semun sun;
  93         struct semid_ds s_ds;
  94         sigset_t sigmask;
  95         int i;
  96
  97         if (argc != 2)
  98                 usage();
  99
 100         /*
 101          * Install a SIGSYS handler so that we can exit gracefully if
 102          * System V Semaphore support isn't in the kernel.
 103          */
 104         sa.sa_handler = sigsys_handler;
 105         sigemptyset(&sa.sa_mask);
 106         sa.sa_flags = 0;
 107         if (sigaction(SIGSYS, &sa, NULL) == -1)
 108                 err(1, "sigaction SIGSYS");
 109
 110         /*
 111          * Install and SIGCHLD handler to deal with all possible exit
 112          * conditions of the receiver.
 113          */
 114         sa.sa_handler = sigchld_handler;
 115         sigemptyset(&sa.sa_mask);
 116         sa.sa_flags = 0;
 117         if (sigaction(SIGCHLD, &sa, NULL) == -1)
 118                 err(1, "sigaction SIGCHLD");
 119
 120         semkey = ftok(argv[1], 4160);
 121
 122         /*
 123          * Initialize child_pid to ourselves to that the cleanup function
 124          * works before we create the receiver.
 125          */
 126         child_pid = getpid();
 127
 128         /*
 129          * Make sure that when the sender exits, the message queue is
 130          * removed.
 131          */
 132         if (atexit(cleanup) == -1)
 133                 err(1, "atexit");
 134
 135         if ((sender_semid = semget(semkey, 1, IPC_CREAT | 0640)) == -1)
 136                 err(1, "semget");
 137
 138
 139         sun.buf = &s_ds;
 140         if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
 141                 err(1, "semctl IPC_STAT");
 142
 143         print_semid_ds(&s_ds, 0640);
 144
 145         s_ds.sem_perm.mode = (s_ds.sem_perm.mode & ~0777) | 0600;
 146
 147         sun.buf = &s_ds;
 148         if (semctl(sender_semid, 0, IPC_SET, sun) == -1)
 149                 err(1, "semctl IPC_SET");
 150
 151         memset(&s_ds, 0, sizeof(s_ds));
 152
 153         sun.buf = &s_ds;
 154         if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
 155                 err(1, "semctl IPC_STAT");
 156
 157         if ((s_ds.sem_perm.mode & 0777) != 0600)
 158                 err(1, "IPC_SET of mode didn't hold");
 159
 160         print_semid_ds(&s_ds, 0600);
 161
 162         for (child_count = 0; child_count < 5; child_count++) {
 163                 switch ((child_pid = fork())) {
 164                 case -1:
 165                         err(1, "fork");
 166                         /* NOTREACHED */
 167
 168                 case 0:
 169                         waiter();
 170                         break;
 171
 172                 default:
 173                         break;
 174                 }
 175         }
 176
 177         /*
 178          * Wait for all of the waiters to be attempting to acquire the
 179          * semaphore.
 180          */
 181         for (;;) {
 182                 i = semctl(sender_semid, 0, GETNCNT);
 183                 if (i == -1)
 184                         err(1, "semctl GETNCNT");
 185                 if (i == 5)
 186                         break;
 187         }
 188
 189         /*
 190          * Now set the thundering herd in motion by initializing the
 191          * semaphore to the value 1.
 192          */
 193         sun.val = 1;
 194         if (semctl(sender_semid, 0, SETVAL, sun) == -1)
 195                 err(1, "sender: semctl SETVAL to 1");
 196
 197         /*
 198          * Suspend forever; when we get SIGCHLD, the handler will exit.
 199          */
 200         sigemptyset(&sigmask);
 201         for (;;) {
 202                 (void) sigsuspend(&sigmask);
 203                 if (signal_was_sigchld)
 204                         signal_was_sigchld = 0;
 205                 else
 206                         break;
 207         }
 208
 209         /*
 210          * ...and any other signal is an unexpected error.
 211          */
 212         errx(1, "sender: received unexpected signal");
 213 }
 214
 215 void
 216 sigsys_handler(int signo)
 217 {
 218
 219         errx(1, "System V Semaphore support is not present in the kernel");
 220 }
 221
 222 void
 223 sigchld_handler(int signo)
 224 {
 225         union semun sun;
 226         struct semid_ds s_ds;
 227         int cstatus;
 228
 229         /*
 230          * Reap the child; if it exited successfully, then we're on the
 231          * right track!
 232          */
 233         if (wait(&cstatus) == -1)
 234                 err(1, "wait");
 235
 236         if (WIFEXITED(cstatus) == 0)
 237                 errx(1, "receiver exited abnormally");
 238
 239         if (WEXITSTATUS(cstatus) != 0)
 240                 errx(1, "receiver exited with status %d",
 241                     WEXITSTATUS(cstatus));
 242
 243         /*
 244          * If we get here, the child has exited normally, and we should
 245          * decrement the child count.  If the child_count reaches 0, we
 246          * should exit.
 247          */
 248
 249         sun.buf = &s_ds;
 250         if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
 251                 err(1, "semctl IPC_STAT");
 252
 253         print_semid_ds(&s_ds, 0600);
 254
 255         if (--child_count != 0) {
 256                 signal_was_sigchld = 1;
 257                 return;
 258         }
 259
 260         exit(0);
 261 }
 262
 263 void
 264 cleanup()
 265 {
 266
 267         /*
 268          * If we're the sender, and it exists, remove the message queue.
 269          */
 270         if (child_pid != 0 && sender_semid != -1) {
 271                 if (semctl(sender_semid, 0, IPC_RMID) == -1)
 272                         warn("semctl IPC_RMID");
 273         }
 274 }
 275
 276 void
 277 print_semid_ds(struct semid_ds *sp, mode_t mode)
 278 {
 279         uid_t uid = geteuid();
 280         gid_t gid = getegid();
 281
 282         printf("PERM: uid %d, gid %d, cuid %d, cgid %d, mode 0%o\n",
 283             sp->sem_perm.uid, sp->sem_perm.gid,
 284             sp->sem_perm.cuid, sp->sem_perm.cgid,
 285             sp->sem_perm.mode & 0777);
 286
 287         printf("nsems %u\n", sp->sem_nsems);
 288
 289         printf("otime: %s", ctime(&sp->sem_otime));
 290         printf("ctime: %s", ctime(&sp->sem_ctime));
 291
 292         /*
 293          * Sanity check a few things.
 294          */
 295
 296         if (sp->sem_perm.uid != uid || sp->sem_perm.cuid != uid)
 297                 errx(1, "uid mismatch");
 298
 299         if (sp->sem_perm.gid != gid || sp->sem_perm.cgid != gid)
 300                 errx(1, "gid mismatch");
 301
 302         if ((sp->sem_perm.mode & 0777) != mode)
 303                 errx(1, "mode mismatch %o != %o",
 304                     (sp->sem_perm.mode & 0777), mode);
 305 }
 306
 307 void
 308 usage()
 309 {
 310
 311         fprintf(stderr, "usage: %s keypath\n", getprogname());
 312         exit(1);
 313 }
 314
 315 void
 316 waiter()
 317 {
 318         struct sembuf s;
 319         int semid;
 320
 321         if ((semid = semget(semkey, 1, 0)) == -1)
 322                 err(1, "waiter: semget");
 323
 324         /*
 325          * Attempt to acquire the semaphore.
 326          */
 327         s.sem_num = 0;
 328         s.sem_op = -1;
 329         s.sem_flg = SEM_UNDO;
 330
 331         if (semop(semid, &s, 1) == -1)
 332                 err(1, "waiter: semop -1");
 333
 334         printf("WOO!  GOT THE SEMAPHORE!\n");
 335         sleep(1);
 336
 337         /*
 338          * Release the semaphore and exit.
 339          */
 340         s.sem_num = 0;
 341         s.sem_op = 1;
 342         s.sem_flg = SEM_UNDO;
 343
 344         if (semop(semid, &s, 1) == -1)
 345                 err(1, "waiter: semop +1");
 346
 347         exit(0);
 348 }