misc/tst-select.c

   1 /* Test for select timeout.
   2    Copyright (C) 2021-2023 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 <errno.h>
  20 #include <intprops.h>
  21 #include <support/capture_subprocess.h>
  22 #include <support/check.h>
  23 #include <support/support.h>
  24 #include <support/timespec.h>
  25 #include <support/xunistd.h>
  26 #include <support/xtime.h>
  27 #include <support/xsignal.h>
  28
  29 struct child_args
  30 {
  31   int fds[2][2];
  32   struct timeval tmo;
  33 };
  34
  35 static void
  36 do_test_child (void *clousure)
  37 {
  38   struct child_args *args = (struct child_args *) clousure;
  39
  40   close (args->fds[0][1]);
  41   close (args->fds[1][0]);
  42
  43   fd_set rfds;
  44   FD_ZERO (&rfds);
  45   FD_SET (args->fds[0][0], &rfds);
  46
  47   struct timespec ts = xclock_now (CLOCK_REALTIME);
  48   ts = timespec_add (ts, (struct timespec) { args->tmo.tv_sec, 0 });
  49
  50   int r = select (args->fds[0][0] + 1, &rfds, NULL, NULL, &args->tmo);
  51   TEST_COMPARE (r, 0);
  52
  53   if (support_select_modifies_timeout ())
  54     {
  55       TEST_COMPARE (args->tmo.tv_sec, 0);
  56       TEST_COMPARE (args->tmo.tv_usec, 0);
  57     }
  58
  59   TEST_TIMESPEC_NOW_OR_AFTER (CLOCK_REALTIME, ts);
  60
  61   xwrite (args->fds[1][1], "foo", 3);
  62 }
  63
  64 static void
  65 do_test_child_alarm (void *clousure)
  66 {
  67   struct child_args *args = (struct child_args *) clousure;
  68
  69   support_create_timer (0, 100000000, false, NULL);
  70   struct timeval tv = { .tv_sec = args->tmo.tv_sec, .tv_usec = 0 };
  71   int r = select (0, NULL, NULL, NULL, &tv);
  72   TEST_COMPARE (r, -1);
  73   if (args->tmo.tv_sec > INT_MAX)
  74     TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
  75   else
  76     {
  77       TEST_COMPARE (errno, EINTR);
  78       if (support_select_modifies_timeout ())
  79        TEST_VERIFY (tv.tv_sec < args->tmo.tv_sec);
  80     }
  81 }
  82
  83 static int
  84 do_test (void)
  85 {
  86   struct child_args args;
  87
  88   xpipe (args.fds[0]);
  89   xpipe (args.fds[1]);
  90
  91   /* The child select should timeout and write on its pipe end.  */
  92   args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 250000 };
  93   {
  94     struct support_capture_subprocess result;
  95     result = support_capture_subprocess (do_test_child, &args);
  96     support_capture_subprocess_check (&result, "tst-select-child", 0,
  97                                       sc_allow_none);
  98   }
  99
 100   if (support_select_normalizes_timeout ())
 101     {
 102       /* This is handled as 1 second instead of failing with EINVAL.  */
 103       args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 1000000 };
 104       struct support_capture_subprocess result;
 105       result = support_capture_subprocess (do_test_child, &args);
 106       support_capture_subprocess_check (&result, "tst-select-child", 0,
 107                                         sc_allow_none);
 108     }
 109
 110   /* Same as before, but simulating polling.  */
 111   args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 0 };
 112   {
 113     struct support_capture_subprocess result;
 114     result = support_capture_subprocess (do_test_child, &args);
 115     support_capture_subprocess_check (&result, "tst-select-child", 0,
 116                                       sc_allow_none);
 117   }
 118
 119   xclose (args.fds[0][0]);
 120   xclose (args.fds[1][1]);
 121
 122   args.tmo = (struct timeval) { .tv_sec = 10, .tv_usec = 0 };
 123   {
 124     struct support_capture_subprocess result;
 125     result = support_capture_subprocess (do_test_child_alarm, &args);
 126     support_capture_subprocess_check (&result, "tst-select-child", 0,
 127                                       sc_allow_none);
 128   }
 129
 130   args.tmo = (struct timeval) { .tv_sec = TYPE_MAXIMUM (time_t),
 131                                 .tv_usec = 0 };
 132   {
 133     struct support_capture_subprocess result;
 134     result = support_capture_subprocess (do_test_child_alarm, &args);
 135     support_capture_subprocess_check (&result, "tst-select-child", 0,
 136                                       sc_allow_none);
 137   }
 138
 139   args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 0 };
 140   {
 141     fd_set rfds;
 142     FD_ZERO (&rfds);
 143     FD_SET (args.fds[1][0], &rfds);
 144
 145     int r = select (args.fds[1][0] + 1, &rfds, NULL, NULL, &args.tmo);
 146     TEST_COMPARE (r, 1);
 147   }
 148
 149   return 0;
 150 }
 151
 152 #include <support/test-driver.c>