gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/kernel/table_test.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  	"testing"
    19  
    20  	"gvisor.dev/gvisor/pkg/abi"
    21  	"gvisor.dev/gvisor/pkg/sentry/arch"
    22  )
    23  
    24  const (
    25  	maxTestSyscall = 1000
    26  )
    27  
    28  func createSyscallTable() *SyscallTable {
    29  	m := make(map[uintptr]Syscall)
    30  	for i := uintptr(0); i <= maxTestSyscall; i++ {
    31  		j := i
    32  		m[i] = Syscall{
    33  			Fn: func(t *Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *SyscallControl, error) {
    34  				return j, nil, nil
    35  			},
    36  		}
    37  	}
    38  
    39  	s := &SyscallTable{
    40  		OS:    abi.Linux,
    41  		Arch:  arch.AMD64,
    42  		Table: m,
    43  	}
    44  
    45  	RegisterSyscallTable(s)
    46  	return s
    47  }
    48  
    49  func TestTable(t *testing.T) {
    50  	table := createSyscallTable()
    51  	defer func() {
    52  		// Cleanup registered tables to keep tests separate.
    53  		allSyscallTables = []*SyscallTable{}
    54  	}()
    55  
    56  	// Go through all functions and check that they return the right value.
    57  	for i := uintptr(0); i < maxTestSyscall; i++ {
    58  		fn := table.Lookup(i)
    59  		if fn == nil {
    60  			t.Errorf("Syscall %v is set to nil", i)
    61  			continue
    62  		}
    63  
    64  		v, _, _ := fn(nil, i, arch.SyscallArguments{})
    65  		if v != i {
    66  			t.Errorf("Wrong return value for syscall %v: expected %v, got %v", i, i, v)
    67  		}
    68  	}
    69  
    70  	// Check that values outside the range return nil.
    71  	for i := uintptr(maxTestSyscall + 1); i < maxTestSyscall+100; i++ {
    72  		fn := table.Lookup(i)
    73  		if fn != nil {
    74  			t.Errorf("Syscall %v is not nil: %v", i, fn)
    75  			continue
    76  		}
    77  	}
    78  }
    79  
    80  func BenchmarkTableLookup(b *testing.B) {
    81  	table := createSyscallTable()
    82  
    83  	b.ResetTimer()
    84  
    85  	j := uintptr(0)
    86  	for i := 0; i < b.N; i++ {
    87  		table.Lookup(j)
    88  		j = (j + 1) % 310
    89  	}
    90  
    91  	b.StopTimer()
    92  	// Cleanup registered tables to keep tests separate.
    93  	allSyscallTables = []*SyscallTable{}
    94  }
    95  
    96  func BenchmarkTableMapLookup(b *testing.B) {
    97  	table := createSyscallTable()
    98  
    99  	b.ResetTimer()
   100  
   101  	j := uintptr(0)
   102  	for i := 0; i < b.N; i++ {
   103  		table.mapLookup(j)
   104  		j = (j + 1) % 310
   105  	}
   106  
   107  	b.StopTimer()
   108  	// Cleanup registered tables to keep tests separate.
   109  	allSyscallTables = []*SyscallTable{}
   110  }