sys/targets: don't use HostFuzzer mode for test OS

We set HostFuzzer for all test targets b/c in some contexts
they needed the same special behavior as real HostFuzzer targets
(e.g no checking enabled syscalls).
However, in some other contexts they don't the same special
behavior as real HostFuzzer targets. For example, pkg/ipc
does rate limiting for HostFuzzer and pkg/runtest don't run
C tests for HostFuzzer.

Add special case for test targets in pkg/host,
and don't set HostFuzzer for all test targets
(keep it for one target for better coverage).

2 files changed, 9 insertions, 4 deletions

diff --git a/pkg/host/features.go b/pkg/host/features.go
index 10137f2d9..800e3ea19 100644
--- a/pkg/host/features.go
+++ b/pkg/host/features.go
@@ -66,7 +66,7 @@ func Check(target *prog.Target) (*Features, error) {
 		FeatureDevlinkPCI:       {Name: "devlink PCI setup", Reason: unsupported},
 		FeatureUSBEmulation:     {Name: "USB emulation", Reason: unsupported},
 	}
-	if targets.Get(target.OS, target.Arch).HostFuzzer {
+	if noHostChecks(target) {
 		return res, nil
 	}
 	for n, check := range checkFeature {
@@ -86,7 +86,7 @@ func Check(target *prog.Target) (*Features, error) {
 // Setup enables and does any one-time setup for the requested features on the host.
 // Note: this can be called multiple times and must be idempotent.
 func Setup(target *prog.Target, features *Features, featureFlags csource.Features, executor string) error {
-	if targets.Get(target.OS, target.Arch).HostFuzzer {
+	if noHostChecks(target) {
 		return nil
 	}
 	args := strings.Split(executor, " ")
@@ -110,3 +110,9 @@ func Setup(target *prog.Target, features *Features, featureFlags csource.Feature
 	_, err := osutil.RunCmd(5*time.Minute, "", executor, args...)
 	return err
 }
+
+func noHostChecks(target *prog.Target) bool {
+	// HostFuzzer targets can't run Go binaries on the targets,
+	// so we actually run on the host on another OS. The same for "test" OS.
+	return targets.Get(target.OS, target.Arch).HostFuzzer || target.OS == "test"
+}
diff --git a/pkg/host/syscalls.go b/pkg/host/syscalls.go
index e322fc3b1..2abd3f16b 100644
--- a/pkg/host/syscalls.go
+++ b/pkg/host/syscalls.go
@@ -6,7 +6,6 @@ package host
 import (
 	"github.com/google/syzkaller/pkg/log"
 	"github.com/google/syzkaller/prog"
-	"github.com/google/syzkaller/sys/targets"
 )
 
 // DetectSupportedSyscalls returns list on supported and unsupported syscalls on the host.
@@ -18,7 +17,7 @@ func DetectSupportedSyscalls(target *prog.Target, sandbox string) (
 	unsupported := make(map[*prog.Syscall]string)
 	const disabledAttribute = "has disabled attribute in descriptions"
 	// These do not have own host and parasitize on some other OS.
-	if targets.Get(target.OS, target.Arch).HostFuzzer {
+	if noHostChecks(target) {
 		for _, c := range target.Syscalls {
 			if c.Attrs.Disabled {
 				unsupported[c] = disabledAttribute