sysdeps/unix/sysv/linux/tst-sysvsem-linux.c

   1 /* Basic tests for Linux SYSV semaphore extensions.
   2    Copyright (C) 2020-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <sys/ipc.h>
  20 #include <sys/sem.h>
  21 #include <errno.h>
  22 #include <stdlib.h>
  23 #include <stdbool.h>
  24 #include <stdio.h>
  25
  26 #include <support/check.h>
  27 #include <support/temp_file.h>
  28
  29 /* These are for the temporary file we generate.  */
  30 static char *name;
  31 static int semid;
  32
  33 static void
  34 remove_sem (void)
  35 {
  36   /* Enforce message queue removal in case of early test failure.
  37      Ignore error since the sem may already have being removed.  */
  38   semctl (semid, 0, IPC_RMID, 0);
  39 }
  40
  41 static void
  42 do_prepare (int argc, char *argv[])
  43 {
  44   TEST_VERIFY_EXIT (create_temp_file ("tst-sysvsem.", &name) != -1);
  45 }
  46
  47 #define PREPARE do_prepare
  48
  49 #define SEM_MODE 0644
  50
  51 union semun
  52 {
  53   int val;
  54   struct semid_ds *buf;
  55   unsigned short  *array;
  56   struct seminfo *__buf;
  57 };
  58
  59 struct test_seminfo
  60 {
  61   int semmsl;
  62   int semmns;
  63   int semopm;
  64   int semmni;
  65 };
  66
  67 /* It tries to obtain some system-wide SysV semaphore information from /proc
  68    to check against IPC_INFO/SEM_INFO.  The /proc only returns the tunables
  69    value of SEMMSL, SEMMNS, SEMOPM, and SEMMNI.
  70
  71    The kernel also returns constant value for SEMVMX, SEMMNU, SEMMAP, SEMUME,
  72    and also SEMUSZ and SEMAEM (for IPC_INFO).  The issue to check them is they
  73    might change over kernel releases.  */
  74
  75 static void
  76 read_sem_stat (struct test_seminfo *tseminfo)
  77 {
  78   FILE *f = fopen ("/proc/sys/kernel/sem", "r");
  79   if (f == NULL)
  80     FAIL_UNSUPPORTED ("/proc is not mounted or /proc/sys/kernel/sem is not "
  81                       "available");
  82
  83   int r = fscanf (f, "%d %d %d %d",
  84                   &tseminfo->semmsl, &tseminfo->semmns, &tseminfo->semopm,
  85                   &tseminfo->semmni);
  86   TEST_VERIFY_EXIT (r == 4);
  87
  88   fclose (f);
  89 }
  90
  91
  92 /* Check if the semaphore with IDX (index into the kernel's internal array)
  93    matches the one with KEY.  The CMD is either SEM_STAT or SEM_STAT_ANY.  */
  94
  95 static bool
  96 check_seminfo (int idx, key_t key, int cmd)
  97 {
  98   struct semid_ds seminfo;
  99   int sid = semctl (idx, 0, cmd, (union semun) { .buf = &seminfo });
 100   /* Ignore unused array slot returned by the kernel or information from
 101      unknown semaphores.  */
 102   if ((sid == -1 && errno == EINVAL) || sid != semid)
 103     return false;
 104
 105   if (sid == -1)
 106     FAIL_EXIT1 ("semctl with SEM_STAT failed (errno=%d)", errno);
 107
 108   TEST_COMPARE (seminfo.sem_perm.__key, key);
 109   TEST_COMPARE (seminfo.sem_perm.mode, SEM_MODE);
 110   TEST_COMPARE (seminfo.sem_nsems, 1);
 111
 112   return true;
 113 }
 114
 115 static int
 116 do_test (void)
 117 {
 118   atexit (remove_sem);
 119
 120   key_t key = ftok (name, 'G');
 121   if (key == -1)
 122     FAIL_EXIT1 ("ftok failed: %m");
 123
 124   semid = semget (key, 1, IPC_CREAT | IPC_EXCL | SEM_MODE);
 125   if (semid == -1)
 126     FAIL_EXIT1 ("semget failed: %m");
 127
 128   struct test_seminfo tipcinfo;
 129   read_sem_stat (&tipcinfo);
 130
 131   int semidx;
 132
 133   {
 134     struct seminfo ipcinfo;
 135     semidx = semctl (semid, 0, IPC_INFO, (union semun) { .__buf = &ipcinfo });
 136     if (semidx == -1)
 137       FAIL_EXIT1 ("semctl with IPC_INFO failed: %m");
 138
 139     TEST_COMPARE (ipcinfo.semmsl, tipcinfo.semmsl);
 140     TEST_COMPARE (ipcinfo.semmns, tipcinfo.semmns);
 141     TEST_COMPARE (ipcinfo.semopm, tipcinfo.semopm);
 142     TEST_COMPARE (ipcinfo.semmni, tipcinfo.semmni);
 143   }
 144
 145   /* Same as before but with SEM_INFO.  */
 146   {
 147     struct seminfo ipcinfo;
 148     semidx = semctl (semid, 0, SEM_INFO, (union semun) { .__buf = &ipcinfo });
 149     if (semidx == -1)
 150       FAIL_EXIT1 ("semctl with IPC_INFO failed: %m");
 151
 152     TEST_COMPARE (ipcinfo.semmsl, tipcinfo.semmsl);
 153     TEST_COMPARE (ipcinfo.semmns, tipcinfo.semmns);
 154     TEST_COMPARE (ipcinfo.semopm, tipcinfo.semopm);
 155     TEST_COMPARE (ipcinfo.semmni, tipcinfo.semmni);
 156   }
 157
 158   /* We check if the created semaphore shows in the system-wide status.  */
 159   bool found = false;
 160   for (int i = 0; i <= semidx; i++)
 161     {
 162       /* We can't tell apart if SEM_STAT_ANY is not supported (kernel older
 163          than 4.17) or if the index used is invalid.  So it just check if
 164          value returned from a valid call matches the created semaphore.  */
 165       check_seminfo (i, key, SEM_STAT_ANY);
 166
 167       if (check_seminfo (i, key, SEM_STAT))
 168         {
 169           found = true;
 170           break;
 171         }
 172     }
 173
 174   if (!found)
 175     FAIL_EXIT1 ("semctl with SEM_STAT/SEM_STAT_ANY could not find the "
 176                 "created  semaphore");
 177
 178   if (semctl (semid, 0, IPC_RMID, 0) == -1)
 179     FAIL_EXIT1 ("semctl failed: %m");
 180
 181   return 0;
 182 }
 183
 184 #include <support/test-driver.c>