fix: normalize paths on Windows systems

This change uses / as the One True Path Separator, as the gods of POSIX
intended in their divine wisdom.

On windows, \ characters are converted to /, everywhere and in depth.
However, on posix systems, \ is a valid filename character, and is not
treated specially.  So, instead of splitting on `/[/\\]/`, we can now
just split on `'/'` to get a set of path parts.

This does mean that archives with entries containing \ will extract
differently on Windows systems than on correct systems.  However, this
is also the behavior of both bsdtar and gnutar, so it seems appropriate
to follow suit.

Additionally, dirCache pruning is now done case-insensitively.  On
case-sensitive systems, this potentially results in a few extra lstat
calls.  However, on case-insensitive systems, it prevents incorrect
cache hits.

lib/mkdir.js

@@ -8,6 +8,7 @@ const mkdirp = require('mkdirp')
 const fs = require('fs')
 const path = require('path')
 const chownr = require('chownr')
+const normPath = require('./normalize-windows-path.js')
 
 class SymlinkError extends Error {
   constructor (symlink, path) {
@@ -33,7 +34,11 @@ class CwdError extends Error {
   }
 }
 
+const cGet = (cache, key) => cache.get(normPath(key))
+const cSet = (cache, key, val) => cache.set(normPath(key), val)
+
 module.exports = (dir, opt, cb) => {
+  dir = normPath(dir)
   // if there's any overlap between mask and mode,
   // then we'll need an explicit chmod
   const umask = opt.umask
@@ -49,13 +54,13 @@ module.exports = (dir, opt, cb) => {
   const preserve = opt.preserve
   const unlink = opt.unlink
   const cache = opt.cache
-  const cwd = opt.cwd
+  const cwd = normPath(opt.cwd)
 
   const done = (er, created) => {
     if (er)
       cb(er)
     else {
-      cache.set(dir, true)
+      cSet(cache, dir, true)
       if (created && doChown)
         chownr(created, uid, gid, er => done(er))
       else if (needChmod)
@@ -65,7 +70,7 @@ module.exports = (dir, opt, cb) => {
     }
   }
 
-  if (cache && cache.get(dir) === true)
+  if (cache && cGet(cache, dir) === true)
     return done()
 
   if (dir === cwd) {
@@ -80,7 +85,7 @@ module.exports = (dir, opt, cb) => {
     return mkdirp(dir, {mode}).then(made => done(null, made), done)
 
   const sub = path.relative(cwd, dir)
-  const parts = sub.split(/\/|\\/)
+  const parts = sub.split('/')
   mkdir_(cwd, parts, mode, cache, unlink, cwd, null, done)
 }
 
@@ -89,7 +94,7 @@ const mkdir_ = (base, parts, mode, cache, unlink, cwd, created, cb) => {
     return cb(null, created)
   const p = parts.shift()
   const part = base + '/' + p
-  if (cache.get(part))
+  if (cGet(cache, part))
     return mkdir_(part, parts, mode, cache, unlink, cwd, created, cb)
   fs.mkdir(part, mode, onmkdir(part, parts, mode, cache, unlink, cwd, created, cb))
 }
@@ -123,6 +128,7 @@ const onmkdir = (part, parts, mode, cache, unlink, cwd, created, cb) => er => {
 }
 
 module.exports.sync = (dir, opt) => {
+  dir = normPath(dir)
   // if there's any overlap between mask and mode,
   // then we'll need an explicit chmod
   const umask = opt.umask
@@ -138,17 +144,17 @@ module.exports.sync = (dir, opt) => {
   const preserve = opt.preserve
   const unlink = opt.unlink
   const cache = opt.cache
-  const cwd = opt.cwd
+  const cwd = normPath(opt.cwd)
 
   const done = (created) => {
-    cache.set(dir, true)
+    cSet(cache, dir, true)
     if (created && doChown)
       chownr.sync(created, uid, gid)
     if (needChmod)
       fs.chmodSync(dir, mode)
   }
 
-  if (cache && cache.get(dir) === true)
+  if (cache && cGet(cache, dir) === true)
     return done()
 
   if (dir === cwd) {
@@ -170,32 +176,32 @@ module.exports.sync = (dir, opt) => {
     return done(mkdirp.sync(dir, mode))
 
   const sub = path.relative(cwd, dir)
-  const parts = sub.split(/\/|\\/)
+  const parts = sub.split('/')
   let created = null
   for (let p = parts.shift(), part = cwd;
     p && (part += '/' + p);
     p = parts.shift()) {
-    if (cache.get(part))
+    if (cGet(cache, part))
       continue
 
     try {
       fs.mkdirSync(part, mode)
       created = created || part
-      cache.set(part, true)
+      cSet(cache, part, true)
     } catch (er) {
       if (er.path && path.dirname(er.path) === cwd &&
           (er.code === 'ENOTDIR' || er.code === 'ENOENT'))
         return new CwdError(cwd, er.code)
 
       const st = fs.lstatSync(part)
       if (st.isDirectory()) {
-        cache.set(part, true)
+        cSet(cache, part, true)
         continue
       } else if (unlink) {
         fs.unlinkSync(part)
         fs.mkdirSync(part, mode)
         created = created || part
-        cache.set(part, true)
+        cSet(cache, part, true)
         continue
       } else if (st.isSymbolicLink())
         return new SymlinkError(part, part + '/' + parts.join('/'))

lib/normalize-windows-path.js

@@ -0,0 +1,8 @@
+// on windows, either \ or / are valid directory separators.
+// on unix, \ is a valid character in filenames.
+// so, on windows, and only on windows, we replace all \ chars with /,
+// so that we can use / as our one and only directory separator char.
+
+const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform
+module.exports = platform !== 'win32' ? p => p
+  : p => p.replace(/\\/g, '/')

lib/pack.js

@@ -54,6 +54,7 @@ const ONDRAIN = Symbol('ondrain')
 const fs = require('fs')
 const path = require('path')
 const warner = require('./warn-mixin.js')
+const normPath = require('./normalize-windows-path.js')
 
 const Pack = warner(class Pack extends MiniPass {
   constructor (opt) {
@@ -66,7 +67,7 @@ const Pack = warner(class Pack extends MiniPass {
     this.preservePaths = !!opt.preservePaths
     this.strict = !!opt.strict
     this.noPax = !!opt.noPax
-    this.prefix = (opt.prefix || '').replace(/(\\|\/)+$/, '')
+    this.prefix = normPath(opt.prefix || '')
     this.linkCache = opt.linkCache || new Map()
     this.statCache = opt.statCache || new Map()
     this.readdirCache = opt.readdirCache || new Map()
@@ -133,7 +134,7 @@ const Pack = warner(class Pack extends MiniPass {
   }
 
   [ADDTARENTRY] (p) {
-    const absolute = path.resolve(this.cwd, p.path)
+    const absolute = normPath(path.resolve(this.cwd, p.path))
     // in this case, we don't have to wait for the stat
     if (!this.filter(p.path, p))
       p.resume()
@@ -149,7 +150,7 @@ const Pack = warner(class Pack extends MiniPass {
   }
 
   [ADDFSENTRY] (p) {
-    const absolute = path.resolve(this.cwd, p)
+    const absolute = normPath(path.resolve(this.cwd, p))
     this[QUEUE].push(new PackJob(p, absolute))
     this[PROCESS]()
   }

lib/path-reservations.js

@@ -7,6 +7,7 @@
 // while still allowing maximal safe parallelization.
 
 const assert = require('assert')
+const normPath = require('./normalize-windows-path.js')
 
 module.exports = () => {
   // path => [function or Set]
@@ -20,8 +21,9 @@ module.exports = () => {
   // return a set of parent dirs for a given path
   const { join } = require('path')
   const getDirs = path =>
-    join(path).split(/[\\/]/).slice(0, -1).reduce((set, path) =>
-      set.length ? set.concat(join(set[set.length - 1], path)) : [path], [])
+    normPath(join(path)).split('/').slice(0, -1).reduce((set, path) =>
+      set.length ? set.concat(normPath(join(set[set.length - 1], path)))
+      : [path], [])
 
   // functions currently running
   const running = new Set()

lib/unpack.js

@@ -15,6 +15,7 @@ const mkdir = require('./mkdir.js')
 const wc = require('./winchars.js')
 const pathReservations = require('./path-reservations.js')
 const stripAbsolutePath = require('./strip-absolute-path.js')
+const normPath = require('./normalize-windows-path.js')
 
 const ONENTRY = Symbol('onEntry')
 const CHECKFS = Symbol('checkFs')
@@ -91,6 +92,17 @@ const uint32 = (a, b, c) =>
   : b === b >>> 0 ? b
   : c
 
+const pruneCache = (cache, abs) => {
+  // clear the cache if it's a case-insensitive match, since we can't
+  // know if the current file system is case-sensitive or not.
+  abs = normPath(abs).toLowerCase()
+  for (const path of cache.keys()) {
+    const plower = path.toLowerCase()
+    if (plower === abs || plower.toLowerCase().indexOf(abs + '/') === 0)
+      cache.delete(path)
+  }
+}
+
 class Unpack extends Parser {
   constructor (opt) {
     if (!opt)
@@ -168,7 +180,7 @@ class Unpack extends Parser {
     // links, and removes symlink directories rather than erroring
     this.unlink = !!opt.unlink
 
-    this.cwd = path.resolve(opt.cwd || process.cwd())
+    this.cwd = normPath(path.resolve(opt.cwd || process.cwd()))
     this.strip = +opt.strip || 0
     // if we're not chmodding, then we don't need the process umask
     this.processUmask = opt.noChmod ? 0 : process.umask()
@@ -201,23 +213,23 @@ class Unpack extends Parser {
 
   [CHECKPATH] (entry) {
     if (this.strip) {
-      const parts = entry.path.split(/\/|\\/)
+      const parts = normPath(entry.path).split('/')
       if (parts.length < this.strip)
         return false
       entry.path = parts.slice(this.strip).join('/')
       if (entry.path === '' && entry.type !== 'Directory' && entry.type !== 'GNUDumpDir')
         return false
 
       if (entry.type === 'Link') {
-        const linkparts = entry.linkpath.split(/\/|\\/)
+        const linkparts = normPath(entry.linkpath).split('/')
         if (linkparts.length >= this.strip)
           entry.linkpath = linkparts.slice(this.strip).join('/')
       }
     }
 
     if (!this.preservePaths) {
-      const p = entry.path
-      if (p.match(/(^|\/|\\)\.\.(\\|\/|$)/)) {
+      const p = normPath(entry.path)
+      if (p.split('/').includes('..')) {
         this.warn('TAR_ENTRY_ERROR', `path contains '..'`, {
           entry,
           path: p,
@@ -245,9 +257,9 @@ class Unpack extends Parser {
     }
 
     if (path.isAbsolute(entry.path))
-      entry.absolute = entry.path
+      entry.absolute = normPath(entry.path)
     else
-      entry.absolute = path.resolve(this.cwd, entry.path)
+      entry.absolute = normPath(path.resolve(this.cwd, entry.path))
 
     return true
   }
@@ -293,7 +305,7 @@ class Unpack extends Parser {
   }
 
   [MKDIR] (dir, mode, cb) {
-    mkdir(dir, {
+    mkdir(normPath(dir), {
       uid: this.uid,
       gid: this.gid,
       processUid: this.processUid,
@@ -451,7 +463,8 @@ class Unpack extends Parser {
   }
 
   [HARDLINK] (entry, done) {
-    this[LINK](entry, path.resolve(this.cwd, entry.linkpath), 'link', done)
+    const linkpath = normPath(path.resolve(this.cwd, entry.linkpath))
+    this[LINK](entry, linkpath, 'link', done)
   }
 
   [PEND] () {
@@ -493,14 +506,8 @@ class Unpack extends Parser {
     // then that means we are about to delete the directory we created
     // previously, and it is no longer going to be a directory, and neither
     // is any of its children.
-    if (entry.type !== 'Directory') {
-      for (const path of this.dirCache.keys()) {
-        if (path === entry.absolute ||
-            path.indexOf(entry.absolute + '/') === 0 ||
-            path.indexOf(entry.absolute + '\\') === 0)
-          this.dirCache.delete(path)
-      }
-    }
+    if (entry.type !== 'Directory')
+      pruneCache(this.dirCache, entry.absolute)
 
     this[MKDIR](path.dirname(entry.absolute), this.dmode, er => {
       if (er) {
@@ -556,7 +563,7 @@ class Unpack extends Parser {
   }
 
   [LINK] (entry, linkpath, link, done) {
-    // XXX: get the type ('file' or 'dir') for windows
+    // XXX: get the type ('symlink' or 'junction') for windows
     fs[link](linkpath, entry.absolute, er => {
       if (er)
         this[ONERROR](er, entry)
@@ -571,14 +578,8 @@ class Unpack extends Parser {
 
 class UnpackSync extends Unpack {
   [CHECKFS] (entry) {
-    if (entry.type !== 'Directory') {
-      for (const path of this.dirCache.keys()) {
-        if (path === entry.absolute ||
-            path.indexOf(entry.absolute + '/') === 0 ||
-            path.indexOf(entry.absolute + '\\') === 0)
-          this.dirCache.delete(path)
-      }
-    }
+    if (entry.type !== 'Directory')
+      pruneCache(this.dirCache, entry.absolute)
 
     const er = this[MKDIR](path.dirname(entry.absolute), this.dmode, neverCalled)
     if (er)
@@ -700,7 +701,7 @@ class UnpackSync extends Unpack {
 
   [MKDIR] (dir, mode) {
     try {
-      return mkdir.sync(dir, {
+      return mkdir.sync(normPath(dir), {
         uid: this.uid,
         gid: this.gid,
         processUid: this.processUid,

lib/write-entry.js

@@ -4,12 +4,14 @@ const Pax = require('./pax.js')
 const Header = require('./header.js')
 const fs = require('fs')
 const path = require('path')
+const normPath = require('./normalize-windows-path.js')
+const stripSlash = require('./strip-trailing-slashes.js')
 
 const prefixPath = (path, prefix) => {
   if (!prefix)
     return path
-  path = path.replace(/^\.([/\\]|$)/, '')
-  return prefix + '/' + path
+  path = normPath(path).replace(/^\.(\/|$)/, '')
+  return stripSlash(prefix) + '/' + path
 }
 
 const maxReadSize = 16 * 1024 * 1024
@@ -43,7 +45,7 @@ const WriteEntry = warner(class WriteEntry extends MiniPass {
     super(opt)
     if (typeof p !== 'string')
       throw new TypeError('path is required')
-    this.path = p
+    this.path = normPath(p)
     // suppress atime, ctime, uid, gid, uname, gname
     this.portable = !!opt.portable
     // until node has builtin pwnam functions, this'll have to do
@@ -87,7 +89,7 @@ const WriteEntry = warner(class WriteEntry extends MiniPass {
       p = p.replace(/\\/g, '/')
     }
 
-    this.absolute = opt.absolute || path.resolve(this.cwd, p)
+    this.absolute = normPath(opt.absolute || path.resolve(this.cwd, p))
 
     if (this.path === '')
       this.path = './'