/* x86 variant of the amd64-solaris/context_gpr.c test. */ #include <assert.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/syscall.h> #include <sys/ucontext.h> static siginfo_t si; static ucontext_t uc; /* x0 is always zero, but is visible to Valgrind as uninitialised. */ static int x0; static void sighandler(int sig, siginfo_t *sip, ucontext_t *ucp) { si = *sip; uc = *ucp; ucp->uc_mcontext.gregs[ECX] = x0; } int main(void) { struct sigaction sa; pid_t pid; int eax, ebx, ecx, edx, esi, edi; int y0; /* Uninitialised, but we know px[0] is 0x0. */ int *px = malloc(sizeof(*px)); x0 = px[0]; /* Uninitialised, but we know py[0] is 0x0. */ int *py = malloc(sizeof(*py)); y0 = py[0]; sa.sa_handler = sighandler; sa.sa_flags = SA_SIGINFO; if (sigfillset(&sa.sa_mask)) { perror("sigfillset"); return 1; } if (sigaction(SIGUSR1, &sa, NULL)) { perror("sigaction"); return 1; } pid = getpid(); __asm__ __volatile__( /* Set values in general purpose registers. */ "movl %[y0], %%ebx\n" "movl $0xf1, %%ecx\n" "movl $0xf2, %%edx\n" "movl $0xf3, %%esi\n" "movl $0xf4, %%edi\n" /* Prepare syscall parameters. */ "pushl %[sig]\n" "pushl %[pid]\n" "pushl $0xdeadbeef\n" "movl %[scall], %%eax\n" /* Trigger the signal handler. */ "int $0x91\n" "addl $12, %%esp\n" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx), "=S" (esi), "=D" (edi) : [scall] "i" (SYS_kill), [pid] "a" (pid), [sig] "i" (SIGUSR1), [y0] "m" (y0) : "cc", "memory"); printf("Values in the signal handler:\n"); printf(" eax=%#x, edx=%#x, esi=%#x, edi=%#x\n", uc.uc_mcontext.gregs[EAX], uc.uc_mcontext.gregs[EDX], uc.uc_mcontext.gregs[ESI], uc.uc_mcontext.gregs[EDI]); /* Check that ebx contains an uninitialised value (origin is py[0]). */ if (uc.uc_mcontext.gregs[EBX]) assert(0); printf("Values after the return from the signal handler:\n"); printf(" eax=%#x, edx=%#x, esi=%#x, edi=%#x\n", eax, edx, esi, edi); /* Check that ebx and ecx contain uninitialised values (origin is py[0] and px[0], respectively). */ if (ebx || ecx) assert(0); return 0; }