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Diffstat (limited to 'vendor/go.etcd.io/bbolt/bolt_unix.go')
-rw-r--r--vendor/go.etcd.io/bbolt/bolt_unix.go93
1 files changed, 93 insertions, 0 deletions
diff --git a/vendor/go.etcd.io/bbolt/bolt_unix.go b/vendor/go.etcd.io/bbolt/bolt_unix.go
new file mode 100644
index 000000000..2938fed58
--- /dev/null
+++ b/vendor/go.etcd.io/bbolt/bolt_unix.go
@@ -0,0 +1,93 @@
+// +build !windows,!plan9,!solaris,!aix
+
+package bbolt
+
+import (
+ "fmt"
+ "syscall"
+ "time"
+ "unsafe"
+)
+
+// flock acquires an advisory lock on a file descriptor.
+func flock(db *DB, exclusive bool, timeout time.Duration) error {
+ var t time.Time
+ if timeout != 0 {
+ t = time.Now()
+ }
+ fd := db.file.Fd()
+ flag := syscall.LOCK_NB
+ if exclusive {
+ flag |= syscall.LOCK_EX
+ } else {
+ flag |= syscall.LOCK_SH
+ }
+ for {
+ // Attempt to obtain an exclusive lock.
+ err := syscall.Flock(int(fd), flag)
+ if err == nil {
+ return nil
+ } else if err != syscall.EWOULDBLOCK {
+ return err
+ }
+
+ // If we timed out then return an error.
+ if timeout != 0 && time.Since(t) > timeout-flockRetryTimeout {
+ return ErrTimeout
+ }
+
+ // Wait for a bit and try again.
+ time.Sleep(flockRetryTimeout)
+ }
+}
+
+// funlock releases an advisory lock on a file descriptor.
+func funlock(db *DB) error {
+ return syscall.Flock(int(db.file.Fd()), syscall.LOCK_UN)
+}
+
+// mmap memory maps a DB's data file.
+func mmap(db *DB, sz int) error {
+ // Map the data file to memory.
+ b, err := syscall.Mmap(int(db.file.Fd()), 0, sz, syscall.PROT_READ, syscall.MAP_SHARED|db.MmapFlags)
+ if err != nil {
+ return err
+ }
+
+ // Advise the kernel that the mmap is accessed randomly.
+ err = madvise(b, syscall.MADV_RANDOM)
+ if err != nil && err != syscall.ENOSYS {
+ // Ignore not implemented error in kernel because it still works.
+ return fmt.Errorf("madvise: %s", err)
+ }
+
+ // Save the original byte slice and convert to a byte array pointer.
+ db.dataref = b
+ db.data = (*[maxMapSize]byte)(unsafe.Pointer(&b[0]))
+ db.datasz = sz
+ return nil
+}
+
+// munmap unmaps a DB's data file from memory.
+func munmap(db *DB) error {
+ // Ignore the unmap if we have no mapped data.
+ if db.dataref == nil {
+ return nil
+ }
+
+ // Unmap using the original byte slice.
+ err := syscall.Munmap(db.dataref)
+ db.dataref = nil
+ db.data = nil
+ db.datasz = 0
+ return err
+}
+
+// NOTE: This function is copied from stdlib because it is not available on darwin.
+func madvise(b []byte, advice int) (err error) {
+ _, _, e1 := syscall.Syscall(syscall.SYS_MADVISE, uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), uintptr(advice))
+ if e1 != 0 {
+ err = e1
+ }
+ return
+}