diff options
Diffstat (limited to 'vendor/github.com/containerd/continuity/sysx')
-rw-r--r-- | vendor/github.com/containerd/continuity/sysx/file_posix.go | 128 |
1 files changed, 0 insertions, 128 deletions
diff --git a/vendor/github.com/containerd/continuity/sysx/file_posix.go b/vendor/github.com/containerd/continuity/sysx/file_posix.go deleted file mode 100644 index e28f3a1b5..000000000 --- a/vendor/github.com/containerd/continuity/sysx/file_posix.go +++ /dev/null @@ -1,128 +0,0 @@ -/* - Copyright The containerd Authors. - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. -*/ - -package sysx - -import ( - "os" - "path/filepath" - - "github.com/containerd/continuity/syscallx" -) - -// Readlink returns the destination of the named symbolic link. -// If there is an error, it will be of type *PathError. -func Readlink(name string) (string, error) { - for len := 128; ; len *= 2 { - b := make([]byte, len) - n, e := fixCount(syscallx.Readlink(fixLongPath(name), b)) - if e != nil { - return "", &os.PathError{Op: "readlink", Path: name, Err: e} - } - if n < len { - return string(b[0:n]), nil - } - } -} - -// Many functions in package syscall return a count of -1 instead of 0. -// Using fixCount(call()) instead of call() corrects the count. -func fixCount(n int, err error) (int, error) { - if n < 0 { - n = 0 - } - return n, err -} - -// fixLongPath returns the extended-length (\\?\-prefixed) form of -// path when needed, in order to avoid the default 260 character file -// path limit imposed by Windows. If path is not easily converted to -// the extended-length form (for example, if path is a relative path -// or contains .. elements), or is short enough, fixLongPath returns -// path unmodified. -// -// See https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath -func fixLongPath(path string) string { - // Do nothing (and don't allocate) if the path is "short". - // Empirically (at least on the Windows Server 2013 builder), - // the kernel is arbitrarily okay with < 248 bytes. That - // matches what the docs above say: - // "When using an API to create a directory, the specified - // path cannot be so long that you cannot append an 8.3 file - // name (that is, the directory name cannot exceed MAX_PATH - // minus 12)." Since MAX_PATH is 260, 260 - 12 = 248. - // - // The MSDN docs appear to say that a normal path that is 248 bytes long - // will work; empirically the path must be less then 248 bytes long. - if len(path) < 248 { - // Don't fix. (This is how Go 1.7 and earlier worked, - // not automatically generating the \\?\ form) - return path - } - - // The extended form begins with \\?\, as in - // \\?\c:\windows\foo.txt or \\?\UNC\server\share\foo.txt. - // The extended form disables evaluation of . and .. path - // elements and disables the interpretation of / as equivalent - // to \. The conversion here rewrites / to \ and elides - // . elements as well as trailing or duplicate separators. For - // simplicity it avoids the conversion entirely for relative - // paths or paths containing .. elements. For now, - // \\server\share paths are not converted to - // \\?\UNC\server\share paths because the rules for doing so - // are less well-specified. - if len(path) >= 2 && path[:2] == `\\` { - // Don't canonicalize UNC paths. - return path - } - if !filepath.IsAbs(path) { - // Relative path - return path - } - - const prefix = `\\?` - - pathbuf := make([]byte, len(prefix)+len(path)+len(`\`)) - copy(pathbuf, prefix) - n := len(path) - r, w := 0, len(prefix) - for r < n { - switch { - case os.IsPathSeparator(path[r]): - // empty block - r++ - case path[r] == '.' && (r+1 == n || os.IsPathSeparator(path[r+1])): - // /./ - r++ - case r+1 < n && path[r] == '.' && path[r+1] == '.' && (r+2 == n || os.IsPathSeparator(path[r+2])): - // /../ is currently unhandled - return path - default: - pathbuf[w] = '\\' - w++ - for ; r < n && !os.IsPathSeparator(path[r]); r++ { - pathbuf[w] = path[r] - w++ - } - } - } - // A drive's root directory needs a trailing \ - if w == len(`\\?\c:`) { - pathbuf[w] = '\\' - w++ - } - return string(pathbuf[:w]) -} |