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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * vdso_restorer.c - tests vDSO-based signal restore4 * Copyright (c) 2015 Andrew Lutomirski5 *6 * This makes sure that sa_restorer == NULL keeps working on 32-bit7 * configurations. Modern glibc doesn't use it under any circumstances,8 * so it's easy to overlook breakage.9 *10 * 64-bit userspace has never supported sa_restorer == NULL, so this is11 * 32-bit only.12 */13 14#define _GNU_SOURCE15 16#include <err.h>17#include <stdio.h>18#include <dlfcn.h>19#include <string.h>20#include <signal.h>21#include <unistd.h>22#include <syscall.h>23#include <sys/syscall.h>24 25/* Open-code this -- the headers are too messy to easily use them. */26struct real_sigaction {27 void *handler;28 unsigned long flags;29 void *restorer;30 unsigned int mask[2];31};32 33static volatile sig_atomic_t handler_called;34 35static void handler_with_siginfo(int sig, siginfo_t *info, void *ctx_void)36{37 handler_called = 1;38}39 40static void handler_without_siginfo(int sig)41{42 handler_called = 1;43}44 45int main()46{47 int nerrs = 0;48 struct real_sigaction sa;49 50 void *vdso = dlopen("linux-vdso.so.1",51 RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);52 if (!vdso)53 vdso = dlopen("linux-gate.so.1",54 RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);55 if (!vdso) {56 printf("[SKIP]\tFailed to find vDSO. Tests are not expected to work.\n");57 return 0;58 }59 60 memset(&sa, 0, sizeof(sa));61 sa.handler = handler_with_siginfo;62 sa.flags = SA_SIGINFO;63 sa.restorer = NULL; /* request kernel-provided restorer */64 65 printf("[RUN]\tRaise a signal, SA_SIGINFO, sa.restorer == NULL\n");66 67 if (syscall(SYS_rt_sigaction, SIGUSR1, &sa, NULL, 8) != 0)68 err(1, "raw rt_sigaction syscall");69 70 raise(SIGUSR1);71 72 if (handler_called) {73 printf("[OK]\tSA_SIGINFO handler returned successfully\n");74 } else {75 printf("[FAIL]\tSA_SIGINFO handler was not called\n");76 nerrs++;77 }78 79 printf("[RUN]\tRaise a signal, !SA_SIGINFO, sa.restorer == NULL\n");80 81 sa.flags = 0;82 sa.handler = handler_without_siginfo;83 if (syscall(SYS_sigaction, SIGUSR1, &sa, 0) != 0)84 err(1, "raw sigaction syscall");85 handler_called = 0;86 87 raise(SIGUSR1);88 89 if (handler_called) {90 printf("[OK]\t!SA_SIGINFO handler returned successfully\n");91 } else {92 printf("[FAIL]\t!SA_SIGINFO handler was not called\n");93 nerrs++;94 }95 96 return nerrs;97}98