1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
package lock
import (
"github.com/containers/podman/v3/libpod/lock/file"
)
// FileLockManager manages shared memory locks.
type FileLockManager struct {
locks *file.FileLocks
}
// NewFileLockManager makes a new FileLockManager at the specified directory.
func NewFileLockManager(lockPath string) (Manager, error) {
locks, err := file.CreateFileLock(lockPath)
if err != nil {
return nil, err
}
manager := new(FileLockManager)
manager.locks = locks
return manager, nil
}
// OpenFileLockManager opens an existing FileLockManager at the specified directory.
func OpenFileLockManager(path string) (Manager, error) {
locks, err := file.OpenFileLock(path)
if err != nil {
return nil, err
}
manager := new(FileLockManager)
manager.locks = locks
return manager, nil
}
// AllocateLock allocates a new lock from the manager.
func (m *FileLockManager) AllocateLock() (Locker, error) {
semIndex, err := m.locks.AllocateLock()
if err != nil {
return nil, err
}
lock := new(FileLock)
lock.lockID = semIndex
lock.manager = m
return lock, nil
}
// AllocateAndRetrieveLock allocates the lock with the given ID and returns it.
// If the lock is already allocated, error.
func (m *FileLockManager) AllocateAndRetrieveLock(id uint32) (Locker, error) {
lock := new(FileLock)
lock.lockID = id
lock.manager = m
if err := m.locks.AllocateGivenLock(id); err != nil {
return nil, err
}
return lock, nil
}
// RetrieveLock retrieves a lock from the manager given its ID.
func (m *FileLockManager) RetrieveLock(id uint32) (Locker, error) {
lock := new(FileLock)
lock.lockID = id
lock.manager = m
return lock, nil
}
// FreeAllLocks frees all locks in the manager.
// This function is DANGEROUS. Please read the full comment in locks.go before
// trying to use it.
func (m *FileLockManager) FreeAllLocks() error {
return m.locks.DeallocateAllLocks()
}
// FileLock is an individual shared memory lock.
type FileLock struct {
lockID uint32
manager *FileLockManager
}
// ID returns the ID of the lock.
func (l *FileLock) ID() uint32 {
return l.lockID
}
// Lock acquires the lock.
func (l *FileLock) Lock() {
if err := l.manager.locks.LockFileLock(l.lockID); err != nil {
panic(err.Error())
}
}
// Unlock releases the lock.
func (l *FileLock) Unlock() {
if err := l.manager.locks.UnlockFileLock(l.lockID); err != nil {
panic(err.Error())
}
}
// Free releases the lock, allowing it to be reused.
func (l *FileLock) Free() error {
return l.manager.locks.DeallocateLock(l.lockID)
}
|
