static void __init check_sysemu(void) { void *stack; int pid, n, status; printk("Checking syscall emulation patch for ptrace..."); sysemu_supported = 0; pid = start_ptraced_child(&stack); if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0) goto fail; CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); if (n < 0) panic("check_sysemu : wait failed, errno = %d", errno); if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) panic("check_sysemu : expected SIGTRAP, " "got status = %d", status); n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid()); if(n < 0) panic("check_sysemu : failed to modify system " "call return, errno = %d", errno); if (stop_ptraced_child(pid, stack, 0, 0) < 0) goto fail_stopped; sysemu_supported = 1; printk("OK\n"); set_using_sysemu(!force_sysemu_disabled); return; fail: stop_ptraced_child(pid, stack, 1, 0); fail_stopped: sysemu_supported = 0; printk("missing\n"); }
static void __init check_sysemu(void) { unsigned long regs[MAX_REG_NR]; int pid, n, status, count=0; non_fatal("Checking syscall emulation patch for ptrace..."); sysemu_supported = 0; pid = start_ptraced_child(); if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0) goto fail; CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); if (n < 0) fatal_perror("check_sysemu : wait failed"); if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) fatal("check_sysemu : expected SIGTRAP, got status = %d\n", status); if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) fatal_perror("check_sysemu : PTRACE_GETREGS failed"); if (PT_SYSCALL_NR(regs) != __NR_getpid) { non_fatal("check_sysemu got system call number %d, " "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid); goto fail; } n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid()); if (n < 0) { non_fatal("check_sysemu : failed to modify system call " "return"); goto fail; } if (stop_ptraced_child(pid, 0, 0) < 0) goto fail_stopped; sysemu_supported = 1; non_fatal("OK\n"); set_using_sysemu(!force_sysemu_disabled); non_fatal("Checking advanced syscall emulation patch for ptrace..."); pid = start_ptraced_child(); if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *) PTRACE_O_TRACESYSGOOD) < 0)) fatal_perror("check_sysemu: PTRACE_OLDSETOPTIONS failed"); while (1) { count++; if (ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0) goto fail; CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); if (n < 0) fatal_perror("check_sysemu: wait failed"); if (WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))) { if (!count) { non_fatal("check_sysemu: SYSEMU_SINGLESTEP " "doesn't singlestep"); goto fail; } n = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_RET_OFFSET, os_getpid()); if (n < 0) fatal_perror("check_sysemu : failed to modify " "system call return"); break; } else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) count++; else { non_fatal("check_sysemu: expected SIGTRAP or " "(SIGTRAP | 0x80), got status = %d\n", status); goto fail; } } if (stop_ptraced_child(pid, 0, 0) < 0) goto fail_stopped; sysemu_supported = 2; non_fatal("OK\n"); if (!force_sysemu_disabled) set_using_sysemu(sysemu_supported); return; fail: stop_ptraced_child(pid, 1, 0); fail_stopped: non_fatal("missing\n"); }