go-permbits

Golang File Permission Bit Operators.

Usage

Anywhere you can specify a file mode, you can use the permbits to add together the permissions you want.

(This test works because it's likely the umask is 022 which will mean the first MkdirAll will actually create a directory with 0750 permissions).

testPath := "./test"
mode := permbits.UserAll+permbits.GroupAll

if err := os.MkdirAll(testPath, mode); err != nil {
    log.Fatal(err)
}

if st, err := os.Stat(testPath); err == nil {
    if !permbits.Is(st.Mode(), mode) {
        log.Printf("Updating mode for %s (was %o)", testPath, st.Mode())
        os.Chmod(testPath, mode)
    } else {
        log.Printf("Test path mode is correct: %s (%o)", testPath, st.Mode())
    }
}

$ go run main.go
2021/07/09 13:12:53 Updating mode for ./test (was 20000000750)

Functions

Is(mode, is os.FileMode) bool

Checks whether mode contains all the bits set in is.

Force(mode os.FileMode, want ...os.FileMode) os.FileMode

Takes a base mode and ensures all wanted permission bits are set.

mode := permbits.Force(0o111, permbits.UserReadWriteExecute)
// mode is now 0o711

FromString(perms string) (os.FileMode, error)

Parses symbolic mode strings (a subset of chmod syntax) into an os.FileMode.

Supports references ugoa, operators +-=, and modes rwx.

mode, err := permbits.FromString("u=rw,g=r,o=")
// mode is 0o640

MustString(perms string) os.FileMode

Wrapper around FromString that panics on invalid input.

Constants

Permission Bits

Mode	Constant
u+r	permbits.UserRead
u+w	permbits.UserWrite
u+x	permbits.UserExecute
g+r	permbits.GroupRead
g+w	permbits.GroupWrite
g+x	permbits.GroupExecute
o+r	permbits.OtherRead
o+w	permbits.OtherWrite
o+x	permbits.OtherExecute

Helper Combinations

Mode	Constant
u+r+w	permbits.UserReadWrite
u+r+w+x	permbits.UserReadWriteExecute or permbits.UserAll
g+r+w	permbits.GroupReadWrite
g+r+w+x	permbits.GroupReadWriteExecute or permbits.GroupAll
o+r+w	permbits.OtherReadWrite
o+r+w+x	permbits.OtherReadWriteExecute or permbits.OtherAll