sysdeps/unix/sysv/linux/tst-clone3.c

   1 /* Check if clone (CLONE_THREAD) does not call exit_group (BZ #21512)
   2    Copyright (C) 2017-2019 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 <string.h>
  20 #include <sched.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <sys/syscall.h>
  24 #include <sys/wait.h>
  25 #include <sys/types.h>
  26 #include <linux/futex.h>
  27
  28 #include <stackinfo.h>  /* For _STACK_GROWS_{UP,DOWN}.  */
  29 #include <support/check.h>
  30 #include <stdatomic.h>
  31
  32 /* Test if clone call with CLONE_THREAD does not call exit_group.  The 'f'
  33    function returns '1', which will be used by clone thread to call the
  34    'exit' syscall directly.  If _exit is used instead, exit_group will be
  35    used and thus the thread group will finish with return value of '1'
  36    (where '2' from main thread is expected.  */
  37
  38 static int
  39 f (void *a)
  40 {
  41   return 1;
  42 }
  43
  44 /* Futex wait for TID argument, similar to pthread_join internal
  45    implementation.  */
  46 #define wait_tid(ctid_ptr, ctid_val)                                    \
  47   do {                                                                  \
  48     __typeof (*(ctid_ptr)) __tid;                                       \
  49     /* We need acquire MO here so that we synchronize with the          \
  50        kernel's store to 0 when the clone terminates.  */               \
  51     while ((__tid = atomic_load_explicit (ctid_ptr,                     \
  52                                           memory_order_acquire)) != 0)  \
  53       futex_wait (ctid_ptr, ctid_val);                                  \
  54   } while (0)
  55
  56 static inline int
  57 futex_wait (int *futexp, int val)
  58 {
  59   return syscall (__NR_futex, futexp, FUTEX_WAIT, val);
  60 }
  61
  62 static int
  63 do_test (void)
  64 {
  65   char st[1024] __attribute__ ((aligned));
  66   int clone_flags = CLONE_THREAD;
  67   /* Minimum required flags to used along with CLONE_THREAD.  */
  68   clone_flags |= CLONE_VM | CLONE_SIGHAND;
  69   /* We will used ctid to call on futex to wait for thread exit.  */
  70   clone_flags |= CLONE_CHILD_CLEARTID;
  71   /* Initialize with a known value.  ctid is set to zero by the kernel after the
  72      cloned thread has exited.  */
  73 #define CTID_INIT_VAL 1
  74   pid_t ctid = CTID_INIT_VAL;
  75   pid_t tid;
  76
  77 #ifdef __ia64__
  78   extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
  79                        size_t __child_stack_size, int __flags,
  80                        void *__arg, ...);
  81   tid = __clone2 (f, st, sizeof (st), clone_flags, NULL, /* ptid */ NULL,
  82                   /* tls */ NULL, &ctid);
  83 #else
  84 #if _STACK_GROWS_DOWN
  85   tid = clone (f, st + sizeof (st), clone_flags, NULL, /* ptid */ NULL,
  86                /* tls */ NULL, &ctid);
  87 #elif _STACK_GROWS_UP
  88   tid = clone (f, st, clone_flags, NULL, /* ptid */ NULL, /* tls */ NULL,
  89                &ctid);
  90 #else
  91 #error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
  92 #endif
  93 #endif
  94   if (tid == -1)
  95     FAIL_EXIT1 ("clone failed: %m");
  96
  97   wait_tid (&ctid, CTID_INIT_VAL);
  98
  99   return 2;
 100 }
 101
 102 #define EXPECTED_STATUS 2
 103 #include <support/test-driver.c>