1 2 3 #include <stdio.h> 4 #include <stdlib.h> 5 #include <signal.h> 6 #include "tests/sys_mman.h" 7 8 void sig_handler(int sig){ 9 int var; 10 fprintf(stderr, "caught signal, local var is on %p\n", &var); 11 } 12 13 int main(int argv, char** argc) { 14 int res, i; 15 stack_t sigstk; 16 struct sigaction act; 17 static const int size = SIGSTKSZ*2; 18 // We give EXEC permissions because this won't work on ppc32 unless you 19 // ask for an alt stack with EXEC permissions, 20 // since signal returning requires execution of code on the stack. 21 char *stk = (char *)mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, 22 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); 23 sigstk.ss_sp = stk; 24 25 sigstk.ss_size = size; 26 sigstk.ss_flags = 0; 27 fprintf(stderr, "calling sigaltstack, stack base is %p\n", sigstk.ss_sp); 28 if (sigaltstack(&sigstk,0)<0) perror("sigaltstack"); 29 30 fprintf(stderr,"setting sigaction\n"); 31 act.sa_flags=SA_ONSTACK; 32 act.sa_handler=&sig_handler; 33 sigemptyset(&act.sa_mask); 34 res = sigaction(SIGUSR1,&act,0); 35 fprintf(stderr, "res = %d\n", res); 36 fprintf(stderr, "raising the signal\n"); 37 raise(SIGUSR1); 38 39 /* Loop long enough so valgrind has a forced context switch and 40 actually delivers the signal before the thread exits. */ 41 for (i = 0; i < 1000000; i++) ; 42 43 fprintf(stderr, "done\n"); 44 return 0; 45 } 46
