// SPDX-License-Identifier: GPL-2.0-only
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/*
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* vdso_restorer.c - tests vDSO-based signal restore
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* Copyright (c) 2015 Andrew Lutomirski
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*
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* This makes sure that sa_restorer == NULL keeps working on 32-bit
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* configurations. Modern glibc doesn't use it under any circumstances,
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* so it's easy to overlook breakage.
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*
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* 64-bit userspace has never supported sa_restorer == NULL, so this is
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* 32-bit only.
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*/
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#define _GNU_SOURCE
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#include <err.h>
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#include <stdio.h>
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#include <dlfcn.h>
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#include <string.h>
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#include <signal.h>
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#include <unistd.h>
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#include <syscall.h>
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#include <sys/syscall.h>
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/* Open-code this -- the headers are too messy to easily use them. */
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struct real_sigaction {
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void *handler;
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unsigned long flags;
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void *restorer;
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unsigned int mask[2];
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};
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static volatile sig_atomic_t handler_called;
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static void handler_with_siginfo(int sig, siginfo_t *info, void *ctx_void)
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{
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handler_called = 1;
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}
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static void handler_without_siginfo(int sig)
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{
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handler_called = 1;
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}
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int main()
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{
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int nerrs = 0;
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struct real_sigaction sa;
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void *vdso = dlopen("linux-vdso.so.1",
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RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
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if (!vdso)
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vdso = dlopen("linux-gate.so.1",
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RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
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if (!vdso) {
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printf("[SKIP]\tFailed to find vDSO. Tests are not expected to work.\n");
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return 0;
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}
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memset(&sa, 0, sizeof(sa));
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sa.handler = handler_with_siginfo;
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sa.flags = SA_SIGINFO;
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sa.restorer = NULL; /* request kernel-provided restorer */
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printf("[RUN]\tRaise a signal, SA_SIGINFO, sa.restorer == NULL\n");
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if (syscall(SYS_rt_sigaction, SIGUSR1, &sa, NULL, 8) != 0)
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err(1, "raw rt_sigaction syscall");
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raise(SIGUSR1);
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if (handler_called) {
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printf("[OK]\tSA_SIGINFO handler returned successfully\n");
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} else {
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printf("[FAIL]\tSA_SIGINFO handler was not called\n");
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nerrs++;
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}
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printf("[RUN]\tRaise a signal, !SA_SIGINFO, sa.restorer == NULL\n");
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sa.flags = 0;
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sa.handler = handler_without_siginfo;
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if (syscall(SYS_sigaction, SIGUSR1, &sa, 0) != 0)
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err(1, "raw sigaction syscall");
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handler_called = 0;
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raise(SIGUSR1);
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if (handler_called) {
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printf("[OK]\t!SA_SIGINFO handler returned successfully\n");
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} else {
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printf("[FAIL]\t!SA_SIGINFO handler was not called\n");
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nerrs++;
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}
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}
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