1/* This testcase is part of GDB, the GNU debugger. 2 3 Copyright 2016-2023 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program 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 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18#define _GNU_SOURCE 19#include <stdlib.h> 20#include <unistd.h> 21#include <sched.h> 22#include <pthread.h> 23 24static void 25marker () 26{} 27 28#define STACK_SIZE 0x1000 29 30/* These are used to signal that the threads have started correctly. The 31 GLOBAL_THREAD_COUNT is set to the number of threads in main, then 32 decremented (under a lock) in each new thread. */ 33pthread_mutex_t global_lock = PTHREAD_MUTEX_INITIALIZER; 34int global_thread_count = 0; 35 36static int 37clone_fn (void *unused) 38{ 39 /* Signal that this thread has started correctly. */ 40 if (pthread_mutex_lock (&global_lock) != 0) 41 abort (); 42 global_thread_count--; 43 if (pthread_mutex_unlock (&global_lock) != 0) 44 abort (); 45 46 return 0; 47} 48 49int 50main (void) 51{ 52 int i, pid; 53 unsigned char *stack[6]; 54 55 /* Due to bug gdb/19675 the cloned thread _might_ try to reenter main 56 (this depends on where the displaced instruction is placed for 57 execution). However, if we do reenter main then lets ensure we fail 58 hard rather then just silently executing the code below. */ 59 static int started = 0; 60 if (!started) 61 started = 1; 62 else 63 abort (); 64 65 for (i = 0; i < (sizeof (stack) / sizeof (stack[0])); i++) 66 stack[i] = malloc (STACK_SIZE); 67 68 global_thread_count = (sizeof (stack) / sizeof (stack[0])); 69 70 for (i = 0; i < (sizeof (stack) / sizeof (stack[0])); i++) 71 { 72 pid = clone (clone_fn, stack[i] + STACK_SIZE, CLONE_FILES | CLONE_VM, 73 NULL); 74 } 75 76 for (i = 0; i < (sizeof (stack) / sizeof (stack[0])); i++) 77 free (stack[i]); 78 79 /* Set an alarm so we don't end up stuck waiting for threads that might 80 never start correctly. */ 81 alarm (120); 82 83 /* Now wait for all the threads to start up. */ 84 while (global_thread_count != 0) 85 { 86 /* Force memory barrier so GLOBAL_THREAD_COUNT will be refetched. */ 87 asm volatile ("" ::: "memory"); 88 sleep (1); 89 } 90 91 /* Call marker, this is what GDB is waiting for. */ 92 marker (); 93} 94