1//===- FuzzerUtilPosix.cpp - Misc utils for Posix. ------------------------===//
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-exception
6//
7//===----------------------------------------------------------------------===//
8// Misc utils implementation using Posix API.
9//===----------------------------------------------------------------------===//
10#include "FuzzerPlatform.h"
11#if LIBFUZZER_POSIX
12#include "FuzzerIO.h"
13#include "FuzzerInternal.h"
14#include "FuzzerTracePC.h"
15#include <cassert>
16#include <chrono>
17#include <cstring>
18#include <errno.h>
19#include <iomanip>
20#include <signal.h>
21#include <stdio.h>
22#include <sys/mman.h>
23#include <sys/resource.h>
24#include <sys/syscall.h>
25#include <sys/time.h>
26#include <sys/types.h>
27#include <thread>
28#include <unistd.h>
29
30namespace fuzzer {
31
32static void AlarmHandler(int, siginfo_t *, void *) {
33 Fuzzer::StaticAlarmCallback();
34}
35
36static void (*upstream_segv_handler)(int, siginfo_t *, void *);
37
38static void SegvHandler(int sig, siginfo_t *si, void *ucontext) {
39 assert(si->si_signo == SIGSEGV);
40 if (upstream_segv_handler)
41 return upstream_segv_handler(sig, si, ucontext);
42 Fuzzer::StaticCrashSignalCallback();
43}
44
45static void CrashHandler(int, siginfo_t *, void *) {
46 Fuzzer::StaticCrashSignalCallback();
47}
48
49static void InterruptHandler(int, siginfo_t *, void *) {
50 Fuzzer::StaticInterruptCallback();
51}
52
53static void GracefulExitHandler(int, siginfo_t *, void *) {
54 Fuzzer::StaticGracefulExitCallback();
55}
56
57static void FileSizeExceedHandler(int, siginfo_t *, void *) {
58 Fuzzer::StaticFileSizeExceedCallback();
59}
60
61static void SetSigaction(int signum,
62 void (*callback)(int, siginfo_t *, void *)) {
63 struct sigaction sigact = {};
64 if (sigaction(sig: signum, act: nullptr, oact: &sigact)) {
65 Printf(Fmt: "libFuzzer: sigaction failed with %d\n", errno);
66 exit(status: 1);
67 }
68 if (sigact.sa_flags & SA_SIGINFO) {
69 if (sigact.sa_sigaction) {
70 if (signum != SIGSEGV)
71 return;
72 upstream_segv_handler = sigact.sa_sigaction;
73 }
74 } else {
75 if (sigact.sa_handler != SIG_DFL && sigact.sa_handler != SIG_IGN &&
76 sigact.sa_handler != SIG_ERR)
77 return;
78 }
79
80 struct sigaction new_sigact = {};
81 // Address sanitizer needs SA_ONSTACK (causing the signal handler to run on a
82 // dedicated stack) in order to be able to detect stack overflows; keep the
83 // flag if it's set.
84 new_sigact.sa_flags = SA_SIGINFO | (sigact.sa_flags & SA_ONSTACK);
85 new_sigact.sa_sigaction = callback;
86 if (sigaction(sig: signum, act: &new_sigact, oact: nullptr)) {
87 Printf(Fmt: "libFuzzer: sigaction failed with %d\n", errno);
88 exit(status: 1);
89 }
90}
91
92// Return true on success, false otherwise.
93bool ExecuteCommand(const Command &Cmd, std::string *CmdOutput) {
94 FILE *Pipe = popen(command: Cmd.toString().c_str(), modes: "r");
95 if (!Pipe)
96 return false;
97
98 if (CmdOutput) {
99 char TmpBuffer[128];
100 while (fgets(s: TmpBuffer, n: sizeof(TmpBuffer), stream: Pipe))
101 CmdOutput->append(s: TmpBuffer);
102 }
103 return pclose(stream: Pipe) == 0;
104}
105
106void SetTimer(int Seconds) {
107 struct itimerval T {
108 .it_interval: {.tv_sec: Seconds, .tv_usec: 0}, .it_value: { .tv_sec: Seconds, .tv_usec: 0 }
109 };
110 if (setitimer(ITIMER_REAL, new: &T, old: nullptr)) {
111 Printf(Fmt: "libFuzzer: setitimer failed with %d\n", errno);
112 exit(status: 1);
113 }
114 SetSigaction(SIGALRM, callback: AlarmHandler);
115}
116
117void SetSignalHandler(const FuzzingOptions& Options) {
118 // setitimer is not implemented in emscripten.
119 if (Options.HandleAlrm && Options.UnitTimeoutSec > 0 && !LIBFUZZER_EMSCRIPTEN)
120 SetTimer(Options.UnitTimeoutSec / 2 + 1);
121 if (Options.HandleInt)
122 SetSigaction(SIGINT, callback: InterruptHandler);
123 if (Options.HandleTerm)
124 SetSigaction(SIGTERM, callback: InterruptHandler);
125 if (Options.HandleSegv)
126 SetSigaction(SIGSEGV, callback: SegvHandler);
127 if (Options.HandleBus)
128 SetSigaction(SIGBUS, callback: CrashHandler);
129 if (Options.HandleAbrt)
130 SetSigaction(SIGABRT, callback: CrashHandler);
131 if (Options.HandleIll)
132 SetSigaction(SIGILL, callback: CrashHandler);
133 if (Options.HandleFpe)
134 SetSigaction(SIGFPE, callback: CrashHandler);
135 if (Options.HandleXfsz)
136 SetSigaction(SIGXFSZ, callback: FileSizeExceedHandler);
137 if (Options.HandleUsr1)
138 SetSigaction(SIGUSR1, callback: GracefulExitHandler);
139 if (Options.HandleUsr2)
140 SetSigaction(SIGUSR2, callback: GracefulExitHandler);
141}
142
143void SleepSeconds(int Seconds) {
144 sleep(seconds: Seconds); // Use C API to avoid coverage from instrumented libc++.
145}
146
147unsigned long GetPid() { return (unsigned long)getpid(); }
148
149size_t GetPeakRSSMb() {
150 struct rusage usage;
151 if (getrusage(RUSAGE_SELF, usage: &usage))
152 return 0;
153 if (LIBFUZZER_LINUX || LIBFUZZER_FREEBSD || LIBFUZZER_NETBSD ||
154 LIBFUZZER_EMSCRIPTEN) {
155 // ru_maxrss is in KiB
156 return usage.ru_maxrss >> 10;
157 } else if (LIBFUZZER_APPLE) {
158 // ru_maxrss is in bytes
159 return usage.ru_maxrss >> 20;
160 }
161 assert(0 && "GetPeakRSSMb() is not implemented for your platform");
162 return 0;
163}
164
165FILE *OpenProcessPipe(const char *Command, const char *Mode) {
166 return popen(command: Command, modes: Mode);
167}
168
169int CloseProcessPipe(FILE *F) {
170 return pclose(stream: F);
171}
172
173const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
174 size_t PattLen) {
175 return memmem(haystack: Data, haystacklen: DataLen, needle: Patt, needlelen: PattLen);
176}
177
178std::string DisassembleCmd(const std::string &FileName) {
179 return "objdump -d " + FileName;
180}
181
182std::string SearchRegexCmd(const std::string &Regex) {
183 return "grep '" + Regex + "'";
184}
185
186size_t PageSize() {
187 static size_t PageSizeCached = sysconf(_SC_PAGESIZE);
188 return PageSizeCached;
189}
190
191} // namespace fuzzer
192
193#endif // LIBFUZZER_POSIX
194