99 lines
2.6 KiB
Go
99 lines
2.6 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package mm
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import (
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"bytes"
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"fmt"
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"gvisor.googlesource.com/gvisor/pkg/sentry/context"
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)
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const (
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// If checkInvariants is true, perform runtime checks for invariants
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// expected by the mm package. This is normally disabled since MM is a
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// significant hot path in general, and some such checks (notably
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// memmap.CheckTranslateResult) are very expensive.
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checkInvariants = false
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// If logIOErrors is true, log I/O errors that originate from MM before
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// converting them to EFAULT.
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logIOErrors = false
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)
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// String implements fmt.Stringer.String.
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func (mm *MemoryManager) String() string {
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return mm.DebugString(context.Background())
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}
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// DebugString returns a string containing information about mm for debugging.
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func (mm *MemoryManager) DebugString(ctx context.Context) string {
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mm.mappingMu.RLock()
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defer mm.mappingMu.RUnlock()
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mm.activeMu.RLock()
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defer mm.activeMu.RUnlock()
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return mm.debugStringLocked(ctx)
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}
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// Preconditions: mm.mappingMu and mm.activeMu must be locked.
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func (mm *MemoryManager) debugStringLocked(ctx context.Context) string {
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var b bytes.Buffer
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b.WriteString("VMAs:\n")
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for vseg := mm.vmas.FirstSegment(); vseg.Ok(); vseg = vseg.NextSegment() {
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b.Write(mm.vmaMapsEntryLocked(ctx, vseg))
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}
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b.WriteString("PMAs:\n")
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for pseg := mm.pmas.FirstSegment(); pseg.Ok(); pseg = pseg.NextSegment() {
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b.Write(pseg.debugStringEntryLocked())
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}
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return string(b.Bytes())
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}
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// Preconditions: mm.activeMu must be locked.
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func (pseg pmaIterator) debugStringEntryLocked() []byte {
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var b bytes.Buffer
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fmt.Fprintf(&b, "%08x-%08x ", pseg.Start(), pseg.End())
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pma := pseg.ValuePtr()
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if pma.vmaEffectivePerms.Read {
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b.WriteByte('r')
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} else {
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b.WriteByte('-')
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}
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if pma.vmaEffectivePerms.Write {
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if pma.needCOW {
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b.WriteByte('c')
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} else {
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b.WriteByte('w')
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}
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} else {
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b.WriteByte('-')
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}
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if pma.vmaEffectivePerms.Execute {
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b.WriteByte('x')
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} else {
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b.WriteByte('-')
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}
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if pma.private {
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b.WriteByte('p')
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} else {
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b.WriteByte('s')
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}
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fmt.Fprintf(&b, " %08x %T\n", pma.off, pma.file)
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return b.Bytes()
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}
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