ftrace-lock.c revision 1.1.1.1
1/* This testcase is part of GDB, the GNU debugger. 2 3 Copyright 2015-2016 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#include <pthread.h> 19#include <unistd.h> 20#include "trace-common.h" 21 22/* Called if the testcase failed. */ 23static void 24fail (void) 25{ 26} 27 28static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; 29 30/* This function overrides gdb_collect in the in-process agent library. 31 See gdbserver/tracepoint.c (gdb_collect). We want this function to 32 be ran instead of the one from the library to easily check that only 33 one thread is tracing at a time. 34 35 This works as expected because GDBserver will ask GDB about symbols 36 present in the inferior with the 'qSymbol' packet. And GDB will 37 reply with the address of this function instead of the one from the 38 in-process agent library. */ 39 40void 41gdb_agent_gdb_collect (void *tpoint, unsigned char *regs) 42{ 43 /* If we cannot acquire a lock, then this means another thread is 44 tracing and the lock implemented by the jump pad is not working! */ 45 if (pthread_mutex_trylock (&mutex) != 0) 46 { 47 fail (); 48 return; 49 } 50 51 sleep (1); 52 53 if (pthread_mutex_unlock (&mutex) != 0) 54 { 55 fail (); 56 return; 57 } 58} 59 60static void * 61thread_function (void *arg) 62{ 63 FAST_TRACEPOINT_LABEL(set_point); 64} 65 66static void 67end (void) 68{ 69} 70 71int 72main (int argc, char *argv[], char *envp[]) 73{ 74 pthread_t threads[NUM_THREADS]; 75 int i; 76 77 for (i = 0; i < NUM_THREADS; i++) 78 pthread_create (&threads[i], NULL, thread_function, NULL); 79 80 for (i = 0; i < NUM_THREADS; i++) 81 pthread_join (threads[i], NULL); 82 83 end (); 84 85 return 0; 86} 87