pkg/declextract: refactor netlink generation

Emit all information related to a single netlink family close to each other.
Previously we emitted them scattered and grouped by info type.
That was both inconvinient to emit and inconvinient to read.
NFC.

4 files changed, 42 insertions, 78 deletions

diff --git a/pkg/declextract/declextract.go b/pkg/declextract/declextract.go
index 49a515ddb..f950cee1e 100644
--- a/pkg/declextract/declextract.go
+++ b/pkg/declextract/declextract.go
@@ -22,7 +22,6 @@ func Run(out *Output, syscallRename map[string][]string) ([]byte, []*Interface,
 	ctx.processStructs()
 	ctx.processSyscalls()
 	ctx.processIouring()
-	ctx.fabricateNetlinkPolicies()
 
 	ctx.serialize()
 	ctx.finishInterfaces()
diff --git a/pkg/declextract/entity.go b/pkg/declextract/entity.go
index 57e589e40..6e9ddac85 100644
--- a/pkg/declextract/entity.go
+++ b/pkg/declextract/entity.go
@@ -80,9 +80,6 @@ type Struct struct {
 	IsPacked bool     `json:"is_packed,omitempty"`
 	Align    int      `json:"align,omitempty"`
 	Fields   []*Field `json:"fields,omitempty"`
-
-	// TODO: remove me.
-	isVarlen bool
 }
 
 type Enum struct {
diff --git a/pkg/declextract/netlink.go b/pkg/declextract/netlink.go
index ad80122dc..3f2384cc6 100644
--- a/pkg/declextract/netlink.go
+++ b/pkg/declextract/netlink.go
@@ -5,69 +5,28 @@ package declextract
 
 import (
 	"fmt"
-	"sort"
 	"strings"
 )
 
-func (ctx *context) fabricateNetlinkPolicies() {
+func (ctx *context) serializeNetlink() {
+	// policyQueue helps to emit policies on their first use.
+	pq := &policyQueue{
+		policies: make(map[string]*NetlinkPolicy),
+	}
 	for _, pol := range ctx.NetlinkPolicies {
-		if len(pol.Attrs) == 0 {
-			continue
-		}
-		str := &Struct{
-			Name:     pol.Name + autoSuffix,
-			IsUnion:  true,
-			isVarlen: true,
-		}
-		for _, attr := range pol.Attrs {
-			str.Fields = append(str.Fields, &Field{
-				Name:    attr.Name,
-				syzType: ctx.nlattrType(attr),
-			})
-		}
-		ctx.Structs = append(ctx.Structs, str)
+		pq.policies[pol.Name] = pol
 	}
-	ctx.Structs = sortAndDedupSlice(ctx.Structs)
-}
-
-func (ctx *context) emitNetlinkTypes() {
 	for _, fam := range ctx.NetlinkFamilies {
 		if isEmptyFamily(fam) {
 			continue
 		}
 		id := stringIdentifier(fam.Name)
 		ctx.fmt("resource genl_%v_family_id%v[int16]\n", id, autoSuffix)
-	}
-	for _, fam := range ctx.NetlinkFamilies {
-		if isEmptyFamily(fam) {
-			continue
-		}
-		id := stringIdentifier(fam.Name)
 		ctx.fmt("type msghdr_%v%v[CMD, POLICY] msghdr_netlink[netlink_msg_t"+
 			"[genl_%v_family_id%v, genlmsghdr_t[CMD], POLICY]]\n", id, autoSuffix, id, autoSuffix)
-	}
-	for _, pol := range ctx.NetlinkPolicies {
-		if len(pol.Attrs) == 0 {
-			ctx.fmt("type %v auto_todo\n", pol.Name+autoSuffix)
-		}
-	}
-}
-
-func (ctx *context) emitNetlinkGetFamily() {
-	for _, fam := range ctx.NetlinkFamilies {
-		if isEmptyFamily(fam) {
-			continue
-		}
-		id := stringIdentifier(fam.Name)
 		ctx.fmt("syz_genetlink_get_family_id%v_%v(name ptr[in, string[\"%v\"]],"+
-			" fd sock_nl_generic) genl_%v_family_id%v\n", autoSuffix, id, fam.Name, id, autoSuffix)
-	}
-}
+			" fd sock_nl_generic) genl_%v_family_id%v\n\n", autoSuffix, id, fam.Name, id, autoSuffix)
 
-func (ctx *context) emitNetlinkSendmsgs() {
-	var syscalls []string
-	for _, fam := range ctx.NetlinkFamilies {
-		id := stringIdentifier(fam.Name)
 		dedup := make(map[string]bool)
 		for _, op := range fam.Ops {
 			// TODO: emit these as well, these are dump commands w/o input arguments.
@@ -80,9 +39,10 @@ func (ctx *context) emitNetlinkSendmsgs() {
 				continue
 			}
 			dedup[op.Name] = true
-			syscalls = append(syscalls, fmt.Sprintf("sendmsg%v_%v(fd sock_nl_generic,"+
+			ctx.fmt("sendmsg%v_%v(fd sock_nl_generic,"+
 				" msg ptr[in, msghdr_%v%v[%v, %v]], f flags[send_flags])\n",
-				autoSuffix, op.Name, id, autoSuffix, op.Name, op.Policy+autoSuffix))
+				autoSuffix, op.Name, id, autoSuffix, op.Name, op.Policy+autoSuffix)
+			pq.policyUsed(op.Policy)
 
 			ctx.noteInterface(&Interface{
 				Type:             IfaceNetlinkOp,
@@ -94,11 +54,37 @@ func (ctx *context) emitNetlinkSendmsgs() {
 				AutoDescriptions: true,
 			})
 		}
+
+		for len(pq.pending) != 0 {
+			pol := pq.pending[0]
+			pq.pending = pq.pending[1:]
+			ctx.serializeNetlinkPolicy(pol, pq)
+		}
+	}
+}
+
+type policyQueue struct {
+	policies map[string]*NetlinkPolicy
+	pending  []*NetlinkPolicy
+}
+
+func (pq *policyQueue) policyUsed(name string) {
+	if pol := pq.policies[name]; pol != nil {
+		delete(pq.policies, name)
+		pq.pending = append(pq.pending, pol)
+	}
+}
+
+func (ctx *context) serializeNetlinkPolicy(pol *NetlinkPolicy, pq *policyQueue) {
+	if len(pol.Attrs) == 0 {
+		ctx.fmt("type %v auto_todo\n", pol.Name+autoSuffix)
+		return
 	}
-	sort.Strings(syscalls)
-	for _, call := range syscalls {
-		ctx.fmt("%s", call)
+	ctx.fmt("%v [\n", pol.Name+autoSuffix)
+	for _, attr := range pol.Attrs {
+		ctx.fmt("%v %v\n", attr.Name, ctx.nlattrType(attr, pq))
 	}
+	ctx.fmt("] [varlen]\n")
 }
 
 func isEmptyFamily(fam *NetlinkFamily) bool {
@@ -110,7 +96,7 @@ func isEmptyFamily(fam *NetlinkFamily) bool {
 	return true
 }
 
-func (ctx *context) nlattrType(attr *NetlinkAttr) string {
+func (ctx *context) nlattrType(attr *NetlinkAttr, pq *policyQueue) string {
 	nlattr, typ := "nlattr", ""
 	switch attr.Kind {
 	case "NLA_BITFIELD32":
@@ -124,6 +110,7 @@ func (ctx *context) nlattrType(attr *NetlinkAttr) string {
 		nlattr = "nlnest"
 		policy := "nl_generic_attr"
 		if attr.NestedPolicy != "" {
+			pq.policyUsed(attr.NestedPolicy)
 			policy = attr.NestedPolicy + autoSuffix
 		}
 		typ = fmt.Sprintf("array[%v]", policy)
diff --git a/pkg/declextract/serialization.go b/pkg/declextract/serialization.go
index c737a675c..1bc82a86b 100644
--- a/pkg/declextract/serialization.go
+++ b/pkg/declextract/serialization.go
@@ -14,8 +14,8 @@ func (ctx *context) serialize() {
 	ctx.fmt(header)
 	ctx.serializeIncludes()
 	ctx.serializeEnums()
-	ctx.emitNetlinkTypes()
 	ctx.serializeSyscalls()
+	ctx.serializeNetlink()
 	ctx.serializeStructs()
 	ctx.serializeDefines()
 }
@@ -47,28 +47,12 @@ func (ctx *context) serializeDefines() {
 }
 
 func (ctx *context) serializeSyscalls() {
-	printedGetFamily, printedSendmsg := false, false
 	for _, call := range ctx.Syscalls {
 		ctx.fmt("%v(", call.Func)
 		for i, arg := range call.Args {
 			ctx.fmt("%v%v %v", comma(i), arg.Name, arg.syzType)
 		}
 		ctx.fmt(")\n")
-
-		if call.Func == "syslog$auto" {
-			printedGetFamily = true
-			ctx.emitNetlinkGetFamily()
-		}
-		if call.Func == "sendmsg$auto" {
-			printedSendmsg = true
-			ctx.emitNetlinkSendmsgs()
-		}
-	}
-	if !printedGetFamily {
-		ctx.emitNetlinkGetFamily()
-	}
-	if !printedSendmsg {
-		ctx.emitNetlinkSendmsgs()
 	}
 	ctx.fmt("\n")
 }
@@ -102,9 +86,6 @@ func (ctx *context) serializeStructs() {
 		if str.Align != 0 {
 			attrs = append(attrs, fmt.Sprintf("align[%v]", str.Align))
 		}
-		if str.isVarlen {
-			attrs = append(attrs, "varlen")
-		}
 		if len(attrs) != 0 {
 			ctx.fmt(" [%v]", strings.Join(attrs, ", "))
 		}