sysdeps/unix/sysv/linux/tst-gettid-kill.c

   1 /* Verify the interaction of kill and thread groups.
   2    Copyright (C) 2019-2024 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 /* This test demonstrates that a signal which is sent to a specified
  20    thread ID using the kill function is delivered to the entire thread
  21    group (as if it had been sent to the process group).  */
  22
  23 #include <errno.h>
  24 #include <signal.h>
  25 #include <support/check.h>
  26 #include <support/xsignal.h>
  27 #include <support/xthread.h>
  28 #include <support/xunistd.h>
  29
  30 /* Signal set containing SIGUSR1.  */
  31 static sigset_t sigusr1_set;
  32
  33 /* Used to synchronize the threads.  */
  34 static pthread_barrier_t barrier;
  35
  36 /* TID of the thread to which the signal is sent.  */
  37 static pid_t target_tid;
  38
  39 /* Thread which is expected to receive the SIGUSR1 signal.  */
  40 static pthread_t signal_thread;
  41
  42 /* Pipe used to block and terminate the signal thread.  */
  43 static int pipe_signal[2];
  44
  45 static volatile sig_atomic_t handler_tid;
  46
  47 static void
  48 sigusr1_handler (int signo)
  49 {
  50   TEST_COMPARE (signo, SIGUSR1);
  51   TEST_VERIFY (pthread_self () == signal_thread);
  52   TEST_COMPARE (handler_tid, 0);
  53   handler_tid = gettid ();
  54   TEST_VERIFY (handler_tid > 0);
  55   /* Ensure that the read system call in thread_read exits if the
  56      signal is delivered before the system call is invoked.  */
  57   char ch = 'X';
  58   xwrite (pipe_signal[1], &ch, 1);
  59 }
  60
  61 /* Thread which calls pause without expecting it to return.  The TID
  62    of this thread is used as the target in the kill function call.  */
  63 static void *
  64 thread_pause_noreturn (void *closure)
  65 {
  66   target_tid = gettid ();
  67   TEST_VERIFY (target_tid > 0);
  68   xpthread_barrier_wait (&barrier);
  69   pause ();
  70   FAIL_EXIT1 ("The pause function returned");
  71   return NULL;
  72 }
  73
  74 /* Thread which is expected to receive the signal.  */
  75 static void *
  76 thread_read_signal (void *closure)
  77 {
  78   xpthread_sigmask (SIG_UNBLOCK, &sigusr1_set, NULL);
  79   xpthread_barrier_wait (&barrier);
  80   TEST_VERIFY (target_tid > 0);
  81   TEST_VERIFY (gettid () != target_tid);
  82   char ch;
  83   ssize_t ret = read (pipe_signal[0], &ch, 1);
  84   if (ret == 1)
  85     /* The signal was delivered before we entered the read system
  86        call.  */
  87     TEST_COMPARE (ch, 'X');
  88   else
  89     {
  90       /* The signal was delivered while blocked in the read system
  91          call.  */
  92       TEST_COMPARE (ret, -1);
  93       TEST_COMPARE (errno, EINTR);
  94     }
  95   TEST_COMPARE (handler_tid, gettid ());
  96   return NULL;
  97 }
  98
  99 static int
 100 do_test (void)
 101 {
 102   /* Block the SIGUSR1 signal in all threads.  */
 103   sigemptyset (&sigusr1_set);
 104   sigaddset (&sigusr1_set, SIGUSR1);
 105   xpthread_sigmask (SIG_BLOCK, &sigusr1_set, NULL);
 106
 107   xsignal (SIGUSR1, sigusr1_handler);
 108   xpipe (pipe_signal);
 109
 110   xpthread_barrier_init (&barrier, NULL, 3);
 111
 112   pthread_t target_thread
 113     = xpthread_create (NULL, thread_pause_noreturn, NULL);
 114   signal_thread = xpthread_create (NULL, thread_read_signal, NULL);
 115   xpthread_barrier_wait (&barrier);
 116
 117   /* Send the SIGUSR1 signal to the thread which has it blocked, and
 118      expect it to be delivered to the other thread.  */
 119   TEST_COMPARE (kill (target_tid, SIGUSR1), 0);
 120
 121   xpthread_join (signal_thread);
 122   xpthread_cancel (target_thread);
 123   xpthread_join (target_thread);
 124
 125   xpthread_barrier_destroy (&barrier);
 126   return 0;
 127 }
 128
 129 #include <support/test-driver.c>