github.com/MerlinKodo/gvisor@v0.0.0-20231110090155-957f62ecf90e/pkg/sentry/pgalloc/context.go (about)

     1  // Copyright 2019 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package pgalloc
    16  
    17  import (
    18  	"github.com/MerlinKodo/gvisor/pkg/context"
    19  )
    20  
    21  // contextID is this package's type for context.Context.Value keys.
    22  type contextID int
    23  
    24  const (
    25  	// CtxMemoryFile is a Context.Value key for a MemoryFile.
    26  	CtxMemoryFile contextID = iota
    27  
    28  	// CtxMemoryFileProvider is a Context.Value key for a MemoryFileProvider.
    29  	CtxMemoryFileProvider
    30  
    31  	// CtxMemoryCgroupID is the memory cgroup id which the task belongs to.
    32  	CtxMemoryCgroupID
    33  )
    34  
    35  // MemoryFileFromContext returns the MemoryFile used by ctx, or nil if no such
    36  // MemoryFile exists.
    37  func MemoryFileFromContext(ctx context.Context) *MemoryFile {
    38  	if v := ctx.Value(CtxMemoryFile); v != nil {
    39  		return v.(*MemoryFile)
    40  	}
    41  	return nil
    42  }
    43  
    44  // MemoryFileProviderFromContext returns the MemoryFileProvider used by ctx, or nil if no such
    45  // MemoryFileProvider exists.
    46  func MemoryFileProviderFromContext(ctx context.Context) MemoryFileProvider {
    47  	if v := ctx.Value(CtxMemoryFileProvider); v != nil {
    48  		return v.(MemoryFileProvider)
    49  	}
    50  	return nil
    51  }
    52  
    53  // MemoryCgroupIDFromContext returns the memory cgroup id of the ctx, or
    54  // zero if the ctx does not belong to any memory cgroup.
    55  func MemoryCgroupIDFromContext(ctx context.Context) uint32 {
    56  	if v := ctx.Value(CtxMemoryCgroupID); v != nil {
    57  		return v.(uint32)
    58  	}
    59  	return 0
    60  }