diff options
Diffstat (limited to 'pkg/usermem/usermem.go')
| -rw-r--r-- | pkg/usermem/usermem.go | 119 |
1 files changed, 41 insertions, 78 deletions
diff --git a/pkg/usermem/usermem.go b/pkg/usermem/usermem.go index cd6a0ea6b..9b1e7a085 100644 --- a/pkg/usermem/usermem.go +++ b/pkg/usermem/usermem.go @@ -21,7 +21,6 @@ import ( "io" "strconv" - "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/gohacks" "gvisor.dev/gvisor/pkg/safemem" @@ -54,8 +53,10 @@ type IO interface { // of bytes zeroed. If the number of bytes zeroed is < toZero, it returns a // non-nil error explaining why. // - // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or - // any following locks in the lock order. toZero >= 0. + // Preconditions: + // * The caller must not hold mm.MemoryManager.mappingMu or any + // following locks in the lock order. + // * toZero >= 0. ZeroOut(ctx context.Context, addr Addr, toZero int64, opts IOOpts) (int64, error) // CopyOutFrom copies ars.NumBytes() bytes from src to the memory mapped at @@ -66,9 +67,11 @@ type IO interface { // // CopyOutFrom calls src.ReadToBlocks at most once. // - // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or - // any following locks in the lock order. src.ReadToBlocks must not block - // on mm.MemoryManager.activeMu or any preceding locks in the lock order. + // Preconditions: + // * The caller must not hold mm.MemoryManager.mappingMu or any + // following locks in the lock order. + // * src.ReadToBlocks must not block on mm.MemoryManager.activeMu or + // any preceding locks in the lock order. CopyOutFrom(ctx context.Context, ars AddrRangeSeq, src safemem.Reader, opts IOOpts) (int64, error) // CopyInTo copies ars.NumBytes() bytes from the memory mapped at ars to @@ -78,10 +81,11 @@ type IO interface { // // CopyInTo calls dst.WriteFromBlocks at most once. // - // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or - // any following locks in the lock order. dst.WriteFromBlocks must not - // block on mm.MemoryManager.activeMu or any preceding locks in the lock - // order. + // Preconditions: + // * The caller must not hold mm.MemoryManager.mappingMu or any + // following locks in the lock order. + // * dst.WriteFromBlocks must not block on mm.MemoryManager.activeMu or + // any preceding locks in the lock order. CopyInTo(ctx context.Context, ars AddrRangeSeq, dst safemem.Writer, opts IOOpts) (int64, error) // TODO(jamieliu): The requirement that CopyOutFrom/CopyInTo call src/dst @@ -93,25 +97,28 @@ type IO interface { // SwapUint32 atomically sets the uint32 value at addr to new and // returns the previous value. // - // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or - // any following locks in the lock order. addr must be aligned to a 4-byte - // boundary. + // Preconditions: + // * The caller must not hold mm.MemoryManager.mappingMu or any + // following locks in the lock order. + // * addr must be aligned to a 4-byte boundary. SwapUint32(ctx context.Context, addr Addr, new uint32, opts IOOpts) (uint32, error) // CompareAndSwapUint32 atomically compares the uint32 value at addr to // old; if they are equal, the value in memory is replaced by new. In // either case, the previous value stored in memory is returned. // - // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or - // any following locks in the lock order. addr must be aligned to a 4-byte - // boundary. + // Preconditions: + // * The caller must not hold mm.MemoryManager.mappingMu or any + // following locks in the lock order. + // * addr must be aligned to a 4-byte boundary. CompareAndSwapUint32(ctx context.Context, addr Addr, old, new uint32, opts IOOpts) (uint32, error) // LoadUint32 atomically loads the uint32 value at addr and returns it. // - // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or - // any following locks in the lock order. addr must be aligned to a 4-byte - // boundary. + // Preconditions: + // * The caller must not hold mm.MemoryManager.mappingMu or any + // following locks in the lock order. + // * addr must be aligned to a 4-byte boundary. LoadUint32(ctx context.Context, addr Addr, opts IOOpts) (uint32, error) } @@ -176,51 +183,6 @@ func (rw *IOReadWriter) Write(src []byte) (int, error) { return n, err } -// CopyObjectOut copies a fixed-size value or slice of fixed-size values from -// src to the memory mapped at addr in uio. It returns the number of bytes -// copied. -// -// CopyObjectOut must use reflection to encode src; performance-sensitive -// clients should do encoding manually and use uio.CopyOut directly. -// -// Preconditions: As for IO.CopyOut. -func CopyObjectOut(ctx context.Context, uio IO, addr Addr, src interface{}, opts IOOpts) (int, error) { - w := &IOReadWriter{ - Ctx: ctx, - IO: uio, - Addr: addr, - Opts: opts, - } - // Allocate a byte slice the size of the object being marshaled. This - // adds an extra reflection call, but avoids needing to grow the slice - // during encoding, which can result in many heap-allocated slices. - b := make([]byte, 0, binary.Size(src)) - return w.Write(binary.Marshal(b, ByteOrder, src)) -} - -// CopyObjectIn copies a fixed-size value or slice of fixed-size values from -// the memory mapped at addr in uio to dst. It returns the number of bytes -// copied. -// -// CopyObjectIn must use reflection to decode dst; performance-sensitive -// clients should use uio.CopyIn directly and do decoding manually. -// -// Preconditions: As for IO.CopyIn. -func CopyObjectIn(ctx context.Context, uio IO, addr Addr, dst interface{}, opts IOOpts) (int, error) { - r := &IOReadWriter{ - Ctx: ctx, - IO: uio, - Addr: addr, - Opts: opts, - } - buf := make([]byte, binary.Size(dst)) - if _, err := io.ReadFull(r, buf); err != nil { - return 0, err - } - binary.Unmarshal(buf, ByteOrder, dst) - return int(r.Addr - addr), nil -} - // CopyStringIn tuning parameters, defined outside that function for tests. const ( copyStringIncrement = 64 @@ -233,7 +195,8 @@ const ( // would exceed maxlen, CopyStringIn returns the string truncated to maxlen and // ENAMETOOLONG. // -// Preconditions: As for IO.CopyFromUser. maxlen >= 0. +// Preconditions: Same as IO.CopyFromUser, plus: +// * maxlen >= 0. func CopyStringIn(ctx context.Context, uio IO, addr Addr, maxlen int, opts IOOpts) (string, error) { initLen := maxlen if initLen > copyStringMaxInitBufLen { @@ -287,7 +250,7 @@ func CopyStringIn(ctx context.Context, uio IO, addr Addr, maxlen int, opts IOOpt // less. CopyOutVec returns the number of bytes copied; if this is less than // the maximum, it returns a non-nil error explaining why. // -// Preconditions: As for IO.CopyOut. +// Preconditions: Same as IO.CopyOut. func CopyOutVec(ctx context.Context, uio IO, ars AddrRangeSeq, src []byte, opts IOOpts) (int, error) { var done int for !ars.IsEmpty() && done < len(src) { @@ -311,7 +274,7 @@ func CopyOutVec(ctx context.Context, uio IO, ars AddrRangeSeq, src []byte, opts // less. CopyInVec returns the number of bytes copied; if this is less than the // maximum, it returns a non-nil error explaining why. // -// Preconditions: As for IO.CopyIn. +// Preconditions: Same as IO.CopyIn. func CopyInVec(ctx context.Context, uio IO, ars AddrRangeSeq, dst []byte, opts IOOpts) (int, error) { var done int for !ars.IsEmpty() && done < len(dst) { @@ -335,7 +298,7 @@ func CopyInVec(ctx context.Context, uio IO, ars AddrRangeSeq, dst []byte, opts I // ZeroOutVec returns the number of bytes written; if this is less than the // maximum, it returns a non-nil error explaining why. // -// Preconditions: As for IO.ZeroOut. +// Preconditions: Same as IO.ZeroOut. func ZeroOutVec(ctx context.Context, uio IO, ars AddrRangeSeq, toZero int64, opts IOOpts) (int64, error) { var done int64 for !ars.IsEmpty() && done < toZero { @@ -388,7 +351,7 @@ func isASCIIWhitespace(b byte) bool { // // - CopyInt32StringsInVec returns EINVAL if ars.NumBytes() == 0. // -// Preconditions: As for CopyInVec. +// Preconditions: Same as CopyInVec. func CopyInt32StringsInVec(ctx context.Context, uio IO, ars AddrRangeSeq, dsts []int32, opts IOOpts) (int64, error) { if len(dsts) == 0 { return 0, nil @@ -481,28 +444,28 @@ func (s IOSequence) NumBytes() int64 { // DropFirst returns a copy of s with s.Addrs.DropFirst(n). // -// Preconditions: As for AddrRangeSeq.DropFirst. +// Preconditions: Same as AddrRangeSeq.DropFirst. func (s IOSequence) DropFirst(n int) IOSequence { return IOSequence{s.IO, s.Addrs.DropFirst(n), s.Opts} } // DropFirst64 returns a copy of s with s.Addrs.DropFirst64(n). // -// Preconditions: As for AddrRangeSeq.DropFirst64. +// Preconditions: Same as AddrRangeSeq.DropFirst64. func (s IOSequence) DropFirst64(n int64) IOSequence { return IOSequence{s.IO, s.Addrs.DropFirst64(n), s.Opts} } // TakeFirst returns a copy of s with s.Addrs.TakeFirst(n). // -// Preconditions: As for AddrRangeSeq.TakeFirst. +// Preconditions: Same as AddrRangeSeq.TakeFirst. func (s IOSequence) TakeFirst(n int) IOSequence { return IOSequence{s.IO, s.Addrs.TakeFirst(n), s.Opts} } // TakeFirst64 returns a copy of s with s.Addrs.TakeFirst64(n). // -// Preconditions: As for AddrRangeSeq.TakeFirst64. +// Preconditions: Same as AddrRangeSeq.TakeFirst64. func (s IOSequence) TakeFirst64(n int64) IOSequence { return IOSequence{s.IO, s.Addrs.TakeFirst64(n), s.Opts} } @@ -512,7 +475,7 @@ func (s IOSequence) TakeFirst64(n int64) IOSequence { // As with CopyOutVec, if s.NumBytes() < len(src), the copy will be truncated // to s.NumBytes(), and a nil error will be returned. // -// Preconditions: As for CopyOutVec. +// Preconditions: Same as CopyOutVec. func (s IOSequence) CopyOut(ctx context.Context, src []byte) (int, error) { return CopyOutVec(ctx, s.IO, s.Addrs, src, s.Opts) } @@ -522,7 +485,7 @@ func (s IOSequence) CopyOut(ctx context.Context, src []byte) (int, error) { // As with CopyInVec, if s.NumBytes() < len(dst), the copy will be truncated to // s.NumBytes(), and a nil error will be returned. // -// Preconditions: As for CopyInVec. +// Preconditions: Same as CopyInVec. func (s IOSequence) CopyIn(ctx context.Context, dst []byte) (int, error) { return CopyInVec(ctx, s.IO, s.Addrs, dst, s.Opts) } @@ -532,21 +495,21 @@ func (s IOSequence) CopyIn(ctx context.Context, dst []byte) (int, error) { // As with ZeroOutVec, if s.NumBytes() < toZero, the write will be truncated // to s.NumBytes(), and a nil error will be returned. // -// Preconditions: As for ZeroOutVec. +// Preconditions: Same as ZeroOutVec. func (s IOSequence) ZeroOut(ctx context.Context, toZero int64) (int64, error) { return ZeroOutVec(ctx, s.IO, s.Addrs, toZero, s.Opts) } // CopyOutFrom invokes s.CopyOutFrom over s.Addrs. // -// Preconditions: As for IO.CopyOutFrom. +// Preconditions: Same as IO.CopyOutFrom. func (s IOSequence) CopyOutFrom(ctx context.Context, src safemem.Reader) (int64, error) { return s.IO.CopyOutFrom(ctx, s.Addrs, src, s.Opts) } // CopyInTo invokes s.CopyInTo over s.Addrs. // -// Preconditions: As for IO.CopyInTo. +// Preconditions: Same as IO.CopyInTo. func (s IOSequence) CopyInTo(ctx context.Context, dst safemem.Writer) (int64, error) { return s.IO.CopyInTo(ctx, s.Addrs, dst, s.Opts) } |