tools/syz-check: inject description compilation warnings

Currently we print them as part of `make genereate`,
but nobody reads them, too much output each time.
Don't print them in `make generate` and instead
print in syz-check, the warn files are a good mechanism
to handle "known warnings".

Makefile

@@ -28,7 +28,8 @@ ENV := $(subst \n,$(newline),$(shell \
 	SOURCEDIR=$(SOURCEDIR) HOSTOS=$(HOSTOS) HOSTARCH=$(HOSTARCH) \
 	TARGETOS=$(TARGETOS) TARGETARCH=$(TARGETARCH) TARGETVMARCH=$(TARGETVMARCH) \
 	go run tools/syz-env/env.go))
-$(info $(ENV))
+# Uncomment in case of emergency.
+# $(info $(ENV))
 $(eval $(ENV))
 ifeq ("$(NCORES)", "")
 $(error syz-env failed)

sys/linux/dev_kvm.txt.warn

@@ -1,3 +1,4 @@
+unsupported syscall: ioctl$KVM_ARM_VCPU_INIT due to missing const KVM_ARM_VCPU_INIT
 struct kvm_text_x86: no corresponding struct in kernel
 struct kvm_text_x86_real: no corresponding struct in kernel
 struct kvm_text_x86_16: no corresponding struct in kernel

sys/linux/dev_snd_control.txt.warn

@@ -1,5 +1,6 @@
 struct snd_ctl_elem_info: bad number of fields: syz=12 kernel=8
 field snd_ctl_elem_info.items/value: bad size: syz=4 kernel=128
+len target names_ptr refer to an array with variable-size elements (do you mean bytesize?)
 field snd_ctl_elem_info.item/dimen: bad offset: syz=84 kernel=208
 field snd_ctl_elem_info.item/dimen: bad size: syz=4 kernel=8
 field snd_ctl_elem_info.name/reserved: bad offset: syz=88 kernel=216

sys/linux/netfilter_bridge.txt.warn

@@ -1,3 +1,4 @@
+len target entries refer to an array with variable-size elements (do you mean bytesize?)
 struct ebt_getinfo: no corresponding struct in kernel
 struct ebt_get_entries: no corresponding struct in kernel
 struct ebt_ip_info: bad number of fields: syz=12 kernel=10

sys/linux/sys.txt.warn

@@ -1,3 +1,4 @@
+unsupported syscall: sendfile64 due to missing const __NR_sendfile64
 field seccomp_metadata.flags: bad size: syz=4 kernel=8
 struct pipefd: no corresponding struct in kernel
 struct stat: bad size: syz=68 kernel=144

sys/linux/trusty.txt.warn

@@ -4,6 +4,8 @@ struct trusty_password_handle: no corresponding struct in kernel
 struct trusty_km_secure_msg: no corresponding struct in kernel
 struct trusty_km_supported_digests: no corresponding struct in kernel
 struct trusty_km_configure: no corresponding struct in kernel
+len target params refer to an array with variable-size elements (do you mean bytesize?)
+len target elements refer to an array with variable-size elements (do you mean bytesize?)
 struct trusty_authorization_bytes: no corresponding struct in kernel
 struct trusty_avb_rollback_index: no corresponding struct in kernel
 struct trusty_storage_file_close_req: no corresponding struct in kernel

sys/linux/vusb.txt.warn

@@ -1,6 +1,10 @@
+len target configs refer to an array with variable-size elements (do you mean bytesize?)
+len target interfaces refer to an array with variable-size elements (do you mean bytesize?)
+len target endpoints refer to an array with variable-size elements (do you mean bytesize?)
 struct vusb_connect_string_descriptor: no corresponding struct in kernel
 struct vusb_descriptors: no corresponding struct in kernel
 struct vusb_responses: no corresponding struct in kernel
+len target caps refer to an array with variable-size elements (do you mean bytesize?)
 struct usb_wireless_cap_descriptor: no corresponding struct in kernel
 struct usb_ext_cap_descriptor: bad number of fields: syz=7 kernel=4
 field usb_ext_cap_descriptor.bmAttributes1/bmAttributes: bad bit size/offset: syz=8/0 kernel=0/0

sys/syz-sysgen/sysgen.go

@@ -111,6 +111,8 @@ func main() {
 
 				job.ArchData = generateExecutorSyscalls(job.Target, prog.Syscalls, rev)
 
+				// Don't print warnings, they are printed in syz-check.
+				job.Errors = nil
 				job.OK = true
 			}()
 		}
@@ -131,7 +133,6 @@ func main() {
 			for u := range job.Unsupported {
 				unsupported[u]++
 			}
-			fmt.Printf("\n")
 		}
 		oses = append(oses, OSData{
 			GOOS:  OS,

tools/syz-check/check.go

@@ -74,7 +74,7 @@ func main() {
 }
 
 func check(OS, arch, obj string) error {
-	structDescs, locs, err := parseDescriptions(OS, arch)
+	structDescs, locs, warnings1, err := parseDescriptions(OS, arch)
 	if err != nil {
 		return err
 	}
@@ -82,11 +82,11 @@ func check(OS, arch, obj string) error {
 	if err != nil {
 		return err
 	}
-	warnings, err := checkImpl(structs, structDescs, locs)
+	warnings2, err := checkImpl(structs, structDescs, locs)
 	if err != nil {
 		return err
 	}
-	return writeWarnings(OS, arch, warnings)
+	return writeWarnings(OS, arch, append(warnings1, warnings2...))
 }
 
 type Warn struct {
@@ -224,22 +224,24 @@ func checkStruct(typ *prog.StructDesc, astStruct *ast.Struct, str *dwarf.StructT
 	return warnings, nil
 }
 
-func parseDescriptions(OS, arch string) ([]*prog.KeyedStruct, map[string]*ast.Struct, error) {
+func parseDescriptions(OS, arch string) ([]*prog.KeyedStruct, map[string]*ast.Struct, []Warn, error) {
 	errorBuf := new(bytes.Buffer)
+	var warnings []Warn
 	eh := func(pos ast.Pos, msg string) {
+		warnings = append(warnings, Warn{pos, msg})
 		fmt.Fprintf(errorBuf, "%v: %v\n", pos, msg)
 	}
 	top := ast.ParseGlob(filepath.Join("sys", OS, "*.txt"), eh)
 	if top == nil {
-		return nil, nil, fmt.Errorf("failed to parse txt files:\n%s", errorBuf.Bytes())
+		return nil, nil, nil, fmt.Errorf("failed to parse txt files:\n%s", errorBuf.Bytes())
 	}
 	consts := compiler.DeserializeConstsGlob(filepath.Join("sys", OS, "*_"+arch+".const"), eh)
 	if consts == nil {
-		return nil, nil, fmt.Errorf("failed to parse const files:\n%s", errorBuf.Bytes())
+		return nil, nil, nil, fmt.Errorf("failed to parse const files:\n%s", errorBuf.Bytes())
 	}
 	prg := compiler.Compile(top, consts, targets.Get(OS, arch), eh)
 	if prg == nil {
-		return nil, nil, fmt.Errorf("failed to compile descriptions:\n%s", errorBuf.Bytes())
+		return nil, nil, nil, fmt.Errorf("failed to compile descriptions:\n%s", errorBuf.Bytes())
 	}
 	prog.RestoreLinks(prg.Syscalls, prg.Resources, prg.StructDescs)
 	locs := make(map[string]*ast.Struct)
@@ -249,5 +251,5 @@ func parseDescriptions(OS, arch string) ([]*prog.KeyedStruct, map[string]*ast.St
 			locs[n.Name.Name] = n
 		}
 	}
-	return prg.StructDescs, locs, nil
+	return prg.StructDescs, locs, warnings, nil
 }