56 lines
1.2 KiB
Go
56 lines
1.2 KiB
Go
//go:build ((freebsd || openbsd || netbsd || dragonfly || illumos) && (386 || arm || amd64 || arm64 || riscv64 || ppc64le)) || sqlite3_flock || sqlite3_dotlk
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package vfs
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import "github.com/ncruces/go-sqlite3/internal/util"
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// +checklocks:s.Mutex
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func (s *vfsShm) shmMemLock(offset, n int32, flags _ShmFlag) _ErrorCode {
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switch {
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case flags&_SHM_UNLOCK != 0:
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for i := offset; i < offset+n; i++ {
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if s.lock[i] {
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if s.vfsShmParent.lock[i] == 0 {
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panic(util.AssertErr())
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}
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if s.vfsShmParent.lock[i] <= 0 {
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s.vfsShmParent.lock[i] = 0
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} else {
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s.vfsShmParent.lock[i]--
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}
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s.lock[i] = false
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}
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}
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case flags&_SHM_SHARED != 0:
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for i := offset; i < offset+n; i++ {
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if s.lock[i] {
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panic(util.AssertErr())
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}
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if s.vfsShmParent.lock[i]+1 <= 0 {
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return _BUSY
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}
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}
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for i := offset; i < offset+n; i++ {
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s.vfsShmParent.lock[i]++
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s.lock[i] = true
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}
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case flags&_SHM_EXCLUSIVE != 0:
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for i := offset; i < offset+n; i++ {
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if s.lock[i] {
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panic(util.AssertErr())
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}
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if s.vfsShmParent.lock[i] != 0 {
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return _BUSY
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}
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}
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for i := offset; i < offset+n; i++ {
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s.vfsShmParent.lock[i] = -1
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s.lock[i] = true
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}
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default:
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panic(util.AssertErr())
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}
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return _OK
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}
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