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Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/x86/vdso_restorer.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/tools/testing/selftests/x86/vdso_restorer.c b/tools/testing/selftests/x86/vdso_restorer.c new file mode 100644 index 000000000..fe99f2434 --- /dev/null +++ b/tools/testing/selftests/x86/vdso_restorer.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * vdso_restorer.c - tests vDSO-based signal restore + * Copyright (c) 2015 Andrew Lutomirski + * + * 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 <dlfcn.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; + + void *vdso = dlopen("linux-vdso.so.1", + RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD); + if (!vdso) + vdso = dlopen("linux-gate.so.1", + RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD); + if (!vdso) { + printf("[SKIP]\tFailed to find vDSO. Tests are not expected to work.\n"); + return 0; + } + + memset(&sa, 0, sizeof(sa)); + sa.handler = handler_with_siginfo; + sa.flags = SA_SIGINFO; + sa.restorer = NULL; /* request kernel-provided restorer */ + + printf("[RUN]\tRaise a signal, SA_SIGINFO, sa.restorer == NULL\n"); + + 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++; + } + + printf("[RUN]\tRaise a signal, !SA_SIGINFO, sa.restorer == NULL\n"); + + 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++; + } +} |