github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/kernel/uts_namespace.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 kernel
    16  
    17  import (
    18  	"github.com/SagerNet/gvisor/pkg/sentry/kernel/auth"
    19  	"github.com/SagerNet/gvisor/pkg/sync"
    20  )
    21  
    22  // UTSNamespace represents a UTS namespace, a holder of two system identifiers:
    23  // the hostname and domain name.
    24  //
    25  // +stateify savable
    26  type UTSNamespace struct {
    27  	// mu protects all fields below.
    28  	mu         sync.Mutex `state:"nosave"`
    29  	hostName   string
    30  	domainName string
    31  
    32  	// userns is the user namespace associated with the UTSNamespace.
    33  	// Privileged operations on this UTSNamespace must have appropriate
    34  	// capabilities in userns.
    35  	//
    36  	// userns is immutable.
    37  	userns *auth.UserNamespace
    38  }
    39  
    40  // NewUTSNamespace creates a new UTS namespace.
    41  func NewUTSNamespace(hostName, domainName string, userns *auth.UserNamespace) *UTSNamespace {
    42  	return &UTSNamespace{
    43  		hostName:   hostName,
    44  		domainName: domainName,
    45  		userns:     userns,
    46  	}
    47  }
    48  
    49  // UTSNamespace returns the task's UTS namespace.
    50  func (t *Task) UTSNamespace() *UTSNamespace {
    51  	t.mu.Lock()
    52  	defer t.mu.Unlock()
    53  	return t.utsns
    54  }
    55  
    56  // HostName returns the host name of this UTS namespace.
    57  func (u *UTSNamespace) HostName() string {
    58  	u.mu.Lock()
    59  	defer u.mu.Unlock()
    60  	return u.hostName
    61  }
    62  
    63  // SetHostName sets the host name of this UTS namespace.
    64  func (u *UTSNamespace) SetHostName(host string) {
    65  	u.mu.Lock()
    66  	defer u.mu.Unlock()
    67  	u.hostName = host
    68  }
    69  
    70  // DomainName returns the domain name of this UTS namespace.
    71  func (u *UTSNamespace) DomainName() string {
    72  	u.mu.Lock()
    73  	defer u.mu.Unlock()
    74  	return u.domainName
    75  }
    76  
    77  // SetDomainName sets the domain name of this UTS namespace.
    78  func (u *UTSNamespace) SetDomainName(domain string) {
    79  	u.mu.Lock()
    80  	defer u.mu.Unlock()
    81  	u.domainName = domain
    82  }
    83  
    84  // UserNamespace returns the user namespace associated with this UTS namespace.
    85  func (u *UTSNamespace) UserNamespace() *auth.UserNamespace {
    86  	u.mu.Lock()
    87  	defer u.mu.Unlock()
    88  	return u.userns
    89  }
    90  
    91  // Clone makes a copy of this UTS namespace, associating the given user
    92  // namespace.
    93  func (u *UTSNamespace) Clone(userns *auth.UserNamespace) *UTSNamespace {
    94  	u.mu.Lock()
    95  	defer u.mu.Unlock()
    96  	return &UTSNamespace{
    97  		hostName:   u.hostName,
    98  		domainName: u.domainName,
    99  		userns:     userns,
   100  	}
   101  }