executor: test extension points

Test that extension points keep stable interface and work.

6 files changed, 63 insertions, 10 deletions

diff --git a/executor/common.h b/executor/common.h
index f4201ca45..2ee0d5bd2 100644
--- a/executor/common.h
+++ b/executor/common.h
@@ -507,7 +507,11 @@ static uint16 csum_inet_digest(struct csum_inet* csum)
 #error "unknown OS"
 #endif
 
+#if SYZ_TEST_COMMON_EXT_EXAMPLE
+#include "common_ext_example.h"
+#else
 #include "common_ext.h"
+#endif
 
 #if SYZ_EXECUTOR || __NR_syz_execute_func
 // syz_execute_func(text ptr[in, text[taget]])
diff --git a/executor/common_ext.h b/executor/common_ext.h
index 6485852ef..22361649f 100644
--- a/executor/common_ext.h
+++ b/executor/common_ext.h
@@ -2,8 +2,10 @@
 // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
 
 // This file is included into executor and C reproducers and can be used to add
-// non-mainline pseudo-syscalls w/o changing any other files.
-// These syscalls should start with syz_ext_.
+// non-mainline pseudo-syscalls and to provide some other extension points
+// w/o changing any other files. See common_ext_example.h for an example implementation.
+
+// Pseudo-syscalls defined in this file should start with syz_ext_.
 
 // This file can also define SYZ_HAVE_SETUP_EXT to 1 and provide
 // void setup_ext() function that will be called during VM setup.
diff --git a/executor/common_ext_example.h b/executor/common_ext_example.h
new file mode 100644
index 000000000..0299b6d4f
--- /dev/null
+++ b/executor/common_ext_example.h
@@ -0,0 +1,10 @@
+// Copyright 2022 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.
+
+// An example implementation of common_ext.h used for testing.
+
+#define SYZ_HAVE_SETUP_EXT 1
+static void setup_ext()
+{
+	debug("example setup_ext called\n");
+}
diff --git a/executor/common_ext_test.go b/executor/common_ext_test.go
new file mode 100644
index 000000000..45ba3a3cf
--- /dev/null
+++ b/executor/common_ext_test.go
@@ -0,0 +1,34 @@
+// Copyright 2022 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 executor
+
+import (
+	"bytes"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/google/syzkaller/pkg/csource"
+	"github.com/google/syzkaller/pkg/osutil"
+	"github.com/google/syzkaller/prog"
+)
+
+func TestCommonExt(t *testing.T) {
+	target, err := prog.GetTarget("test", "64_fork")
+	if err != nil {
+		t.Fatal(err)
+	}
+	bin, err := csource.BuildFile(target, "executor.cc", "-DSYZ_TEST_COMMON_EXT_EXAMPLE=1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(bin)
+	out, err := osutil.RunCmd(time.Minute, "", bin, "setup")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Contains(out, []byte("example setup_ext called")) {
+		t.Fatalf("setup_ext wasn't called:\n%s", out)
+	}
+}
diff --git a/pkg/csource/build.go b/pkg/csource/build.go
index 13633382e..0855dc038 100644
--- a/pkg/csource/build.go
+++ b/pkg/csource/build.go
@@ -17,7 +17,7 @@ import (
 
 // 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, "", true)
+	return build(target, src, "")
 }
 
 // BuildNoWarn is the same as Build, but ignores all compilation warnings.
@@ -25,15 +25,15 @@ func Build(target *prog.Target, src []byte) (string, error) {
 // using an old repro with newer compiler, or a compiler that we never seen before.
 // In these cases it's more important to build successfully.
 func BuildNoWarn(target *prog.Target, src []byte) (string, error) {
-	return build(target, src, "", false)
+	return build(target, src, "", "-fpermissive", "-w")
 }
 
 // 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, true)
+func BuildFile(target *prog.Target, src string, cflags ...string) (string, error) {
+	return build(target, nil, src, cflags...)
 }
 
-func build(target *prog.Target, src []byte, file string, warn bool) (string, error) {
+func build(target *prog.Target, src []byte, file string, cflags ...string) (string, error) {
 	sysTarget := targets.Get(target.OS, target.Arch)
 	compiler := sysTarget.CCompiler
 	// We call the binary syz-executor because it sometimes shows in bug titles,
@@ -59,9 +59,7 @@ func build(target *prog.Target, src []byte, file string, warn bool) (string, err
 		// We do generate uint64's for syscall arguments that overflow longs on 32-bit archs.
 		flags = append(flags, "-Wno-overflow")
 	}
-	if !warn {
-		flags = append(flags, "-fpermissive", "-w")
-	}
+	flags = append(flags, cflags...)
 	cmd := osutil.Command(compiler, flags...)
 	if file == "" {
 		cmd.Stdin = bytes.NewReader(src)
diff --git a/pkg/csource/generated.go b/pkg/csource/generated.go
index 2e213795a..711e74801 100644
--- a/pkg/csource/generated.go
+++ b/pkg/csource/generated.go
@@ -11220,6 +11220,11 @@ static void use_temporary_dir(void)
 #error "unknown OS"
 #endif
 
+#if SYZ_TEST_COMMON_EXT_EXAMPLE
+#include "common_ext_example.h"
+#else
+
+#endif
 
 #if SYZ_EXECUTOR || __NR_syz_execute_func
 static long syz_execute_func(volatile long text)