| #include <stdio.h> |
| #include <stdlib.h> |
| #include <ucontext.h> |
| #include <sys/mman.h> |
| |
| #include "valgrind.h" |
| |
| #define STACK_SIZE 4096 |
| |
| struct ucontext ctx1, ctx2, oldc; |
| int count; |
| |
| void hello(struct ucontext *newc) |
| { |
| printf("hello, world: %d\n", count); |
| if (count++ == 2) |
| newc = &oldc; |
| setcontext(newc); |
| } |
| |
| int init_context(struct ucontext *uc) |
| { |
| void *stack; |
| int ret; |
| |
| if (getcontext(uc) == -1) { |
| perror("getcontext"); |
| exit(1); |
| } |
| |
| stack = (void *)mmap(0, STACK_SIZE, PROT_READ|PROT_WRITE|PROT_EXEC, |
| MAP_ANON|MAP_PRIVATE, -1, 0); |
| |
| if (stack == (void*)-1) { |
| perror("mmap"); |
| exit(1); |
| } |
| |
| ret = VALGRIND_STACK_REGISTER(stack, stack + STACK_SIZE); |
| |
| uc->uc_link = NULL; |
| uc->uc_stack.ss_sp = stack; |
| uc->uc_stack.ss_size = STACK_SIZE; |
| uc->uc_stack.ss_flags = 0; |
| |
| return ret; |
| } |
| |
| int main(int argc, char **argv) |
| { |
| int c1 = init_context(&ctx1); |
| int c2 = init_context(&ctx2); |
| |
| makecontext(&ctx1, (void (*)()) hello, 2, &ctx2); |
| makecontext(&ctx2, (void (*)()) hello, 2, &ctx1); |
| |
| swapcontext(&oldc, &ctx1); |
| |
| VALGRIND_STACK_DEREGISTER(c1); |
| //free(ctx1.uc_stack.ss_sp); |
| VALGRIND_STACK_DEREGISTER(c2); |
| //free(ctx2.uc_stack.ss_sp); |
| |
| return 0; |
| } |