diff options
| -rw-r--r-- | tools/testing/selftests/x86/Makefile | 3 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/vdso_restorer.c | 88 |
2 files changed, 90 insertions, 1 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 398bb0e6e38c..d0c473f65850 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -7,7 +7,8 @@ include ../lib.mk TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ - ldt_gdt + ldt_gdt \ + vdso_restorer TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32) diff --git a/tools/testing/selftests/x86/vdso_restorer.c b/tools/testing/selftests/x86/vdso_restorer.c new file mode 100644 index 000000000000..cb038424a403 --- /dev/null +++ b/tools/testing/selftests/x86/vdso_restorer.c @@ -0,0 +1,88 @@ +/* + * vdso_restorer.c - tests vDSO-based signal restore + * Copyright (c) 2015 Andrew Lutomirski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * This makes sure that sa_restorer == NULL keeps working on 32-bit + * configurations. Modern glibc doesn't use it under any circumstances, + * so it's easy to overlook breakage. + * + * 64-bit userspace has never supported sa_restorer == NULL, so this is + * 32-bit only. + */ + +#define _GNU_SOURCE + +#include <err.h> +#include <stdio.h> +#include <string.h> +#include <signal.h> +#include <unistd.h> +#include <syscall.h> +#include <sys/syscall.h> + +/* Open-code this -- the headers are too messy to easily use them. */ +struct real_sigaction { + void *handler; + unsigned long flags; + void *restorer; + unsigned int mask[2]; +}; + +static volatile sig_atomic_t handler_called; + +static void handler_with_siginfo(int sig, siginfo_t *info, void *ctx_void) +{ + handler_called = 1; +} + +static void handler_without_siginfo(int sig) +{ + handler_called = 1; +} + +int main() +{ + int nerrs = 0; + struct real_sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.handler = handler_with_siginfo; + sa.flags = SA_SIGINFO; + sa.restorer = NULL; /* request kernel-provided restorer */ + + if (syscall(SYS_rt_sigaction, SIGUSR1, &sa, NULL, 8) != 0) + err(1, "raw rt_sigaction syscall"); + + raise(SIGUSR1); + + if (handler_called) { + printf("[OK]\tSA_SIGINFO handler returned successfully\n"); + } else { + printf("[FAIL]\tSA_SIGINFO handler was not called\n"); + nerrs++; + } + + sa.flags = 0; + sa.handler = handler_without_siginfo; + if (syscall(SYS_sigaction, SIGUSR1, &sa, 0) != 0) + err(1, "raw sigaction syscall"); + handler_called = 0; + + raise(SIGUSR1); + + if (handler_called) { + printf("[OK]\t!SA_SIGINFO handler returned successfully\n"); + } else { + printf("[FAIL]\t!SA_SIGINFO handler was not called\n"); + nerrs++; + } +} |