fix(symbolizer): Introduce per-process module maps

Having multiple processes share the same module
maps is a call for chaos. For this reason, each process
now has its distinct map and the export directory contains
cached export entries.

Author: rabbitstack

internal/etw/source_test.go

@@ -805,6 +805,7 @@ func (s *NoopPsSnapshotter) GetSnapshot() []*pstypes.PS
 func (s *NoopPsSnapshotter) AddThread(evt *event.Event) error                   { return nil }
 func (s *NoopPsSnapshotter) AddModule(evt *event.Event) error                   { return nil }
 func (s *NoopPsSnapshotter) FindModule(addr va.Address) (bool, *pstypes.Module) { return false, nil }
+func (s *NoopPsSnapshotter) FindAllModules() map[string]pstypes.Module          { return nil }
 func (s *NoopPsSnapshotter) RemoveThread(pid uint32, tid uint32) error          { return nil }
 func (s *NoopPsSnapshotter) RemoveModule(pid uint32, addr va.Address) error     { return nil }
 func (s *NoopPsSnapshotter) WriteFromCapture(evt *event.Event) error            { return nil }

pkg/ps/snapshotter.go

@@ -55,6 +55,8 @@ type Snapshotter interface {
 	// FindModule traverses loaded modules of all processes in the snapshot and
 	// if there is module with the specified base address, it returns its metadata.
 	FindModule(addr va.Address) (bool, *pstypes.Module)
+	// FindAllModules finds all unique modules across the snapshotter state.
+	FindAllModules() map[string]pstypes.Module
 	// FindAndPut attempts to retrieve process' state for the specified process identifier.
 	// If the process is found, the snapshotter state is updated with the new process.
 	FindAndPut(pid uint32) *pstypes.PS

pkg/ps/snapshotter_mock.go

@@ -57,6 +57,11 @@ func (s *SnapshotterMock) FindModule(addr va.Address) (bool, *pstypes.Module) {
 	return args.Bool(0), nil
 }
 
+func (s *SnapshotterMock) FindAllModules() map[string]pstypes.Module {
+	args := s.Called()
+	return args.Get(0).(map[string]pstypes.Module)
+}
+
 // FindAndPut method
 func (s *SnapshotterMock) FindAndPut(pid uint32) *pstypes.PS {
 	args := s.Called(pid)

pkg/ps/snapshotter_windows.go

@@ -320,6 +320,21 @@ func (s *snapshotter) FindModule(addr va.Address) (bool, *pstypes.Module) {
 	return false, nil
 }
 
+func (s *snapshotter) FindAllModules() map[string]pstypes.Module {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	mods := make(map[string]pstypes.Module)
+	for _, proc := range s.procs {
+		for _, mod := range proc.Modules {
+			if _, ok := mods[mod.Name]; ok {
+				continue
+			}
+			mods[mod.Name] = mod
+		}
+	}
+	return mods
+}
+
 func (s *snapshotter) AddMmap(e *event.Event) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()

pkg/symbolize/exports.go

@@ -0,0 +1,137 @@
+/*
+ * Copyright 2021-present by Nedim Sabic Sabic
+ * https://www.fibratus.io
+ * All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package symbolize
+
+import (
+	"sync"
+	"time"
+
+	"github.com/rabbitstack/fibratus/pkg/ps"
+	"github.com/rabbitstack/fibratus/pkg/util/va"
+	log "github.com/sirupsen/logrus"
+)
+
+// ModuleExports contains exports for the specific module
+// indexed by RVA (Relative Virtual Address).
+type ModuleExports struct {
+	exps map[uint32]string
+}
+
+// SymbolFromRVA finds the closest export address before RVA.
+func (m *ModuleExports) SymbolFromRVA(rva va.Address) string {
+	var exp uint32
+	for f := range m.exps {
+		if uint64(f) <= rva.Uint64() {
+			if exp < f {
+				exp = f
+			}
+		}
+	}
+	if exp != 0 {
+		sym, ok := m.exps[exp]
+		if ok && sym == "" {
+			return "?"
+		}
+		return sym
+	}
+	return ""
+}
+
+// ExportsDirectoryCache stores the cached module exports extracted
+// from the PE export directory.
+type ExportsDirectoryCache struct {
+	sync.RWMutex
+	exports map[string]*ModuleExports
+
+	purger *time.Ticker
+	quit   chan struct{}
+
+	psnap ps.Snapshotter
+}
+
+// NewExportsDirectoryCache returns a fresh instance of the exports directory cache.
+func NewExportsDirectoryCache(psnap ps.Snapshotter) *ExportsDirectoryCache {
+	c := &ExportsDirectoryCache{
+		exports: make(map[string]*ModuleExports),
+		purger:  time.NewTicker(time.Minute * 20),
+		quit:    make(chan struct{}, 1),
+		psnap:   psnap,
+	}
+	return c
+}
+
+// Exports returns the exports for the given module path. If
+// the exports can't be find, then the module PE is parsed
+// and the exports cache updated.
+func (c *ExportsDirectoryCache) Exports(mod string) (*ModuleExports, bool) {
+	c.RLock()
+	exports, ok := c.exports[mod]
+	c.RUnlock()
+	if ok {
+		return exports, true
+	}
+	pe, err := parsePeFile(mod)
+	if err != nil {
+		return nil, false
+	}
+	c.Lock()
+	defer c.Unlock()
+	exports = &ModuleExports{exps: pe.Exports}
+	c.exports[mod] = exports
+	return exports, true
+}
+
+// Clear removes all module exports from the directory cache.
+func (c *ExportsDirectoryCache) Clear() {
+	c.Lock()
+	defer c.Unlock()
+	c.exports = make(map[string]*ModuleExports)
+}
+
+// RemoveExports removes all exports associated with the module.
+func (c *ExportsDirectoryCache) RemoveExports(mod string) {
+	c.Lock()
+	defer c.Unlock()
+	delete(c.exports, mod)
+}
+
+func (c *ExportsDirectoryCache) purge() {
+	for {
+		select {
+		case <-c.purger.C:
+			c.clearExports()
+		case <-c.quit:
+			return
+		}
+	}
+}
+
+// clearExports purges all module exports that
+// don't exist in the global snapshotter state.
+func (c *ExportsDirectoryCache) clearExports() {
+	mods := c.psnap.FindAllModules()
+	c.Lock()
+	defer c.Unlock()
+	for exp := range c.exports {
+		if _, ok := mods[exp]; !ok {
+			log.Debugf("removing stale export %s from directory cache", exp)
+			delete(c.exports, exp)
+		}
+	}
+}

pkg/symbolize/exports_test.go

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2021-present by Nedim Sabic Sabic
+ * https://www.fibratus.io
+ * All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package symbolize
+
+import (
+	"testing"
+
+	"github.com/rabbitstack/fibratus/pkg/util/va"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSymbolFromRVA(t *testing.T) {
+	var tests = []struct {
+		rva            va.Address
+		exports        map[uint32]string
+		expectedSymbol string
+	}{
+		{va.Address(317949), map[uint32]string{
+			9824:   "SHCreateScopeItemFromShellItem",
+			23248:  "SHCreateScopeItemFromIDList",
+			165392: "DllGetClassObject",
+			186368: "SHCreateSearchIDListFromAutoList",
+			238048: "DllCanUnloadNow",
+			240112: "IsShellItemInSearchIndex",
+			240304: "IsMSSearchEnabled",
+			272336: "SHSaveBinaryAutoListToStream",
+			310672: "DllMain",
+			317920: "",
+			320864: "",
+			434000: "SHCreateAutoList",
+			434016: "SHCreateAutoListWithID",
+			555040: "CreateDefaultProviderResolver",
+			571136: "GetGatherAdmin",
+			572592: "SEARCH_RemoteLocationsCscStateCache_IsRemoteLocationInCsc"},
+			"?",
+		},
+		{va.Address(434011), map[uint32]string{
+			9824:   "SHCreateScopeItemFromShellItem",
+			23248:  "SHCreateScopeItemFromIDList",
+			165392: "DllGetClassObject",
+			186368: "SHCreateSearchIDListFromAutoList",
+			238048: "DllCanUnloadNow",
+			240112: "IsShellItemInSearchIndex",
+			240304: "IsMSSearchEnabled",
+			272336: "SHSaveBinaryAutoListToStream",
+			310672: "DllMain",
+			317920: "",
+			320864: "",
+			434000: "SHCreateAutoList",
+			434016: "SHCreateAutoListWithID",
+			555040: "CreateDefaultProviderResolver",
+			571136: "GetGatherAdmin",
+			572592: "SEARCH_RemoteLocationsCscStateCache_IsRemoteLocationInCsc"},
+			"SHCreateAutoList",
+		},
+		{va.Address(4532), map[uint32]string{
+			9824:   "SHCreateScopeItemFromShellItem",
+			23248:  "SHCreateScopeItemFromIDList",
+			165392: "DllGetClassObject",
+			186368: "SHCreateSearchIDListFromAutoList",
+			238048: "DllCanUnloadNow",
+			240112: "IsShellItemInSearchIndex",
+			240304: "IsMSSearchEnabled",
+			572592: "SEARCH_RemoteLocationsCscStateCache_IsRemoteLocationInCsc"},
+			"",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.expectedSymbol, func(t *testing.T) {
+			exps := &ModuleExports{exps: tt.exports}
+			assert.Equal(t, tt.expectedSymbol, exps.SymbolFromRVA(tt.rva))
+		})
+	}
+}