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1//===-- options.inc ---------------------------------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef GWP_ASAN_OPTION10#error "Define GWP_ASAN_OPTION prior to including this file!"11#endif12 13#ifndef GWP_ASAN_DEFAULT_ENABLED14#define GWP_ASAN_DEFAULT_ENABLED true15#endif16 17#ifndef GWP_ASAN_STRINGIFY18#define GWP_ASAN_STRINGIFY(S) GWP_ASAN_STRINGIFY_(S)19#define GWP_ASAN_STRINGIFY_(S) #S20#endif21 22GWP_ASAN_OPTION(bool, Enabled, GWP_ASAN_DEFAULT_ENABLED,23 "Is GWP-ASan enabled? Defaults to " GWP_ASAN_STRINGIFY(24 GWP_ASAN_DEFAULT_ENABLED) ".")25 26GWP_ASAN_OPTION(int, MaxSimultaneousAllocations, 16,27 "Number of simultaneously-guarded allocations available in the "28 "pool. Defaults to 16.")29 30GWP_ASAN_OPTION(int, SampleRate, 5000,31 "The probability (1 / SampleRate) that an allocation is "32 "selected for GWP-ASan sampling. Default is 5000. Sample rates "33 "up to (2^30 - 1) are supported.")34 35// Developer note - This option is not actually processed by GWP-ASan itself. It36// is included here so that a user can specify whether they want signal handlers37// or not. The supporting allocator should inspect this value to see whether38// signal handlers need to be installed, and then use39// crash_handler::installSignalHandlers() in order to install the handlers. Note40// that in order to support signal handlers, you will need to link against the41// optional crash_handler component.42GWP_ASAN_OPTION(43 bool, InstallSignalHandlers, true,44 "Install GWP-ASan signal handlers for SIGSEGV during dynamic loading. This "45 "allows better error reports by providing stack traces for allocation and "46 "deallocation when reporting a memory error. GWP-ASan's signal handler "47 "will forward the signal to any previously-installed handler, and user "48 "programs that install further signal handlers should make sure they do "49 "the same. Note, if the previously installed SIGSEGV handler is SIG_IGN, "50 "we terminate the process after dumping the error report.")51 52GWP_ASAN_OPTION(53 bool, Recoverable, false,54 "Install GWP-ASan's signal handler in recoverable mode. This means that "55 "upon GWP-ASan detecting an error, it'll print the error report, but *not* "56 "crash. Only one crash per sampled allocation will ever be recorded, and "57 "if a sampled allocation does actually cause a crash, it'll permanently "58 "occupy a slot in the pool. The recoverable mode also means that "59 "previously-installed signal handlers will only be triggered for "60 "non-GWP-ASan errors, as all GWP-ASan errors won't be forwarded.")61 62GWP_ASAN_OPTION(bool, InstallForkHandlers, true,63 "Install GWP-ASan atfork handlers to acquire internal locks "64 "before fork and release them after.")65 66GWP_ASAN_OPTION(bool, help, false, "Print a summary of the available options.")67 68// =============================================================================69// ==== WARNING70// =============================================================================71// If you are adding flags to GWP-ASan, please note that GWP-ASan flag strings72// may be parsed by trusted system components (on Android, GWP-ASan flag strings73// are parsed by libc during the dynamic loader). This means that GWP-ASan74// should never feature flags like log paths on disk, because this can lead to75// arbitrary file write and thus privilege escalation. For an example, see the76// setuid ASan log_path exploits: https://www.exploit-db.com/exploits/46241.77//78// Please place all new flags above this warning, so that the warning always79// stays at the bottom.80