gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/limits/context.go (about)

     1  // Copyright 2018 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 limits
    16  
    17  import (
    18  	"gvisor.dev/gvisor/pkg/context"
    19  )
    20  
    21  // contextID is the limit package's type for context.Context.Value keys.
    22  type contextID int
    23  
    24  const (
    25  	// CtxLimits is a Context.Value key for a LimitSet.
    26  	CtxLimits contextID = iota
    27  )
    28  
    29  // FromContext returns the limits that apply to ctx.
    30  func FromContext(ctx context.Context) *LimitSet {
    31  	if v := ctx.Value(CtxLimits); v != nil {
    32  		return v.(*LimitSet)
    33  	}
    34  	return nil
    35  }
    36  
    37  // FromContextOrDie returns FromContext(ctx) if the latter is not nil.
    38  // Otherwise, panic is triggered.
    39  func FromContextOrDie(ctx context.Context) *LimitSet {
    40  	if v := ctx.Value(CtxLimits); v != nil {
    41  		return v.(*LimitSet)
    42  	}
    43  	panic("failed to create limit set from context")
    44  }