posix/tst-wait4.c

   1 /* Tests for wait4.
   2    Copyright (C) 2020 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 <errno.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <sys/wait.h>
  24 #include <sys/resource.h>
  25 #include <signal.h>
  26 #include <time.h>
  27 #include <stdatomic.h>
  28 #include <stdbool.h>
  29
  30 #include <support/xsignal.h>
  31 #include <support/xunistd.h>
  32 #include <support/check.h>
  33 #include <support/process_state.h>
  34
  35 static void
  36 test_child (void)
  37 {
  38   /* First thing, we stop ourselves.  */
  39   raise (SIGSTOP);
  40
  41   /* Hey, we got continued!  */
  42   while (1)
  43     pause ();
  44 }
  45
  46 #ifndef WEXITED
  47 # define WEXITED        0
  48 # define WCONTINUED     0
  49 # define WSTOPPED       WUNTRACED
  50 #endif
  51
  52 /* Set with only SIGCHLD on do_test_waitid.  */
  53 static sigset_t chldset;
  54
  55 #ifdef SA_SIGINFO
  56 static void
  57 sigchld (int signo, siginfo_t *info, void *ctx)
  58 {
  59 }
  60 #endif
  61
  62 static void
  63 check_sigchld (int code, int status, pid_t pid)
  64 {
  65 #ifdef SA_SIGINFO
  66   siginfo_t siginfo;
  67   TEST_COMPARE (sigwaitinfo (&chldset, &siginfo), SIGCHLD);
  68
  69   TEST_COMPARE (siginfo.si_signo, SIGCHLD);
  70   TEST_COMPARE (siginfo.si_code, code);
  71   TEST_COMPARE (siginfo.si_status, status);
  72   TEST_COMPARE (siginfo.si_pid, pid);
  73 #endif
  74 }
  75
  76 static int
  77 do_test_wait4 (pid_t pid)
  78 {
  79   /* Adding process_state_tracing_stop ('t') allows the test to work under
  80      trace programs such as ptrace.  */
  81   enum support_process_state stop_state = support_process_state_stopped
  82                                           | support_process_state_tracing_stop;
  83
  84   support_process_state_wait (pid, stop_state);
  85
  86   check_sigchld (CLD_STOPPED, SIGSTOP, pid);
  87
  88   pid_t ret;
  89   int wstatus;
  90   struct rusage rusage;
  91
  92   ret = wait4 (pid, &wstatus, WUNTRACED|WCONTINUED|WNOHANG, NULL);
  93   if (ret == -1 && errno == ENOTSUP)
  94     FAIL_RET ("waitid WNOHANG on stopped: %m");
  95   TEST_COMPARE (ret, pid);
  96   TEST_VERIFY (WIFSTOPPED (wstatus));
  97
  98   /* Issue again but with struct rusage input.  */
  99   ret = wait4 (pid, &wstatus, WUNTRACED|WCONTINUED|WNOHANG, &rusage);
 100   /* With WNOHANG and WUNTRACED, if the children has not changes its state
 101      since previous call the expected result it 0.  */
 102   TEST_COMPARE (ret, 0);
 103
 104   /* Some sanity tests to check if 'wtatus' and 'rusage' possible
 105      input values.  */
 106   ret = wait4 (pid, NULL, WUNTRACED|WCONTINUED|WNOHANG, &rusage);
 107   TEST_COMPARE (ret, 0);
 108   ret = wait4 (pid, NULL, WUNTRACED|WCONTINUED|WNOHANG, NULL);
 109   TEST_COMPARE (ret, 0);
 110
 111   if (kill (pid, SIGCONT) != 0)
 112     FAIL_RET ("kill (%d, SIGCONT): %m\n", pid);
 113
 114   /* Wait for the child to have continued.  */
 115   support_process_state_wait (pid, support_process_state_sleeping);
 116
 117 #if WCONTINUED != 0
 118   check_sigchld (CLD_CONTINUED, SIGCONT, pid);
 119
 120   ret = wait4 (pid, &wstatus, WCONTINUED|WNOHANG, NULL);
 121   TEST_COMPARE (ret, pid);
 122   TEST_VERIFY (WIFCONTINUED (wstatus));
 123
 124   /* Issue again but with struct rusage input.  */
 125   ret = wait4 (pid, &wstatus, WUNTRACED|WCONTINUED|WNOHANG, &rusage);
 126   /* With WNOHANG and WUNTRACED, if the children has not changes its state
 127      since previous call the expected result it 0.  */
 128   TEST_COMPARE (ret, 0);
 129
 130   /* Now stop him again and test waitpid with WCONTINUED.  */
 131   if (kill (pid, SIGSTOP) != 0)
 132     FAIL_RET ("kill (%d, SIGSTOP): %m\n", pid);
 133
 134   /* Wait the child stop.  The waitid call below will block until it has
 135      stopped, but if we are real quick and enter the waitid system call
 136      before the SIGCHLD has been generated, then it will be discarded and
 137      never delivered.  */
 138   support_process_state_wait (pid, stop_state);
 139
 140   ret = wait4 (pid, &wstatus, WUNTRACED|WNOHANG, &rusage);
 141   TEST_COMPARE (ret, pid);
 142
 143   check_sigchld (CLD_STOPPED, SIGSTOP, pid);
 144
 145   if (kill (pid, SIGCONT) != 0)
 146     FAIL_RET ("kill (%d, SIGCONT): %m\n", pid);
 147
 148   /* Wait for the child to have continued.  */
 149   support_process_state_wait (pid, support_process_state_sleeping);
 150
 151   check_sigchld (CLD_CONTINUED, SIGCONT, pid);
 152
 153   ret = wait4 (pid, &wstatus, WCONTINUED|WNOHANG, NULL);
 154   TEST_COMPARE (ret, pid);
 155   TEST_VERIFY (WIFCONTINUED (wstatus));
 156 #endif
 157
 158   /* Die, child, die!  */
 159   if (kill (pid, SIGKILL) != 0)
 160     FAIL_RET ("kill (%d, SIGKILL): %m\n", pid);
 161
 162   support_process_state_wait (pid, support_process_state_zombie);
 163
 164   ret = wait4 (pid, &wstatus, 0, &rusage);
 165   TEST_COMPARE (ret, pid);
 166   TEST_VERIFY (WIFSIGNALED (wstatus));
 167   TEST_VERIFY (WTERMSIG (wstatus) == SIGKILL);
 168
 169   check_sigchld (CLD_KILLED, SIGKILL, pid);
 170
 171   return 0;
 172 }
 173
 174 static int
 175 do_test (void)
 176 {
 177 #ifdef SA_SIGINFO
 178   {
 179     struct sigaction sa;
 180     sa.sa_flags = SA_SIGINFO | SA_RESTART;
 181     sa.sa_sigaction = sigchld;
 182     sigemptyset (&sa.sa_mask);
 183     xsigaction (SIGCHLD, &sa, NULL);
 184   }
 185 #endif
 186
 187   sigemptyset (&chldset);
 188   sigaddset (&chldset, SIGCHLD);
 189
 190   /* The SIGCHLD shall has blocked at the time of the call to sigwait;
 191      otherwise, the behavior is undefined.  */
 192   sigprocmask (SIG_BLOCK, &chldset, NULL);
 193
 194   pid_t pid = xfork ();
 195   if (pid == 0)
 196     {
 197       test_child ();
 198       _exit (127);
 199     }
 200
 201   do_test_wait4 (pid);
 202
 203   xsignal (SIGCHLD, SIG_IGN);
 204   kill (pid, SIGKILL);          /* Make sure it's dead if we bailed early.  */
 205
 206   return 0;
 207 }
 208
 209 #include <support/test-driver.c>