// Copyright 2017 syzkaller project authors. All rights reserved. // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file. package csource import ( "bytes" "fmt" "io/ioutil" "os" "os/exec" "github.com/google/syzkaller/pkg/osutil" "github.com/google/syzkaller/prog" "github.com/google/syzkaller/sys/targets" ) // Build builds a C program from source src and returns name of the resulting binary. func Build(target *prog.Target, src []byte) (string, error) { return build(target, src, "") } // BuildFile builds a C/C++ program from file src and returns name of the resulting binary. func BuildFile(target *prog.Target, src string) (string, error) { return build(target, nil, src) } func build(target *prog.Target, src []byte, file string) (string, error) { sysTarget := targets.Get(target.OS, target.Arch) compiler := sysTarget.CCompiler if _, err := exec.LookPath(compiler); err != nil { return "", fmt.Errorf("no target compiler %v", compiler) } // We call the binary syz-executor because it sometimes shows in bug titles, // and we don't want 2 different bugs for when a crash is triggered during fuzzing and during repro. bin, err := osutil.TempFile("syz-executor") if err != nil { return "", err } flags := []string{ "-Wall", "-Werror", "-O1", "-g", "-o", bin, "-pthread", "-DGOOS_" + target.OS + "=1", "-DGOARCH_" + target.Arch + "=1", } if file == "" { flags = append(flags, "-x", "c", "-") } else { flags = append(flags, file) } flags = append(flags, sysTarget.CrossCFlags...) if sysTarget.PtrSize == 4 { // We do generate uint64's for syscall arguments that overflow longs on 32-bit archs. flags = append(flags, "-Wno-overflow") } cmd := osutil.Command(compiler, flags...) if file == "" { cmd.Stdin = bytes.NewReader(src) } out, err := cmd.CombinedOutput() if err != nil { os.Remove(bin) if file != "" { src, _ = ioutil.ReadFile(file) } return "", fmt.Errorf("failed to build program:\n%s\n%s\ncompiler invocation: %v %v", src, out, compiler, flags) } return bin, nil } // Format reformats C source using clang-format. func Format(src []byte) ([]byte, error) { stdout, stderr := new(bytes.Buffer), new(bytes.Buffer) cmd := osutil.Command("clang-format", "-assume-filename=/src.c", "-style", style) cmd.Stdin = bytes.NewReader(src) cmd.Stdout = stdout cmd.Stderr = stderr if err := cmd.Run(); err != nil { return src, fmt.Errorf("failed to format source: %v\n%v", err, stderr.String()) } return stdout.Bytes(), nil } // Something acceptable for kernel developers and email-friendly. var style = `{ BasedOnStyle: LLVM, IndentWidth: 2, UseTab: Never, BreakBeforeBraces: Linux, IndentCaseLabels: false, DerivePointerAlignment: false, PointerAlignment: Left, AlignTrailingComments: true, AllowShortBlocksOnASingleLine: false, AllowShortCaseLabelsOnASingleLine: false, AllowShortFunctionsOnASingleLine: false, AllowShortIfStatementsOnASingleLine: false, AllowShortLoopsOnASingleLine: false, ColumnLimit: 80, }`