Stronger protection around parallel installs

Now all tarball pack/unpack operations are wrapped in a lock

lib/cache.js

@@ -54,6 +54,8 @@ exports = module.exports = cache
 exports.read = read
 exports.clean = clean
 exports.unpack = unpack
+exports.lock = lock
+exports.unlock = unlock
 
 var mkdir = require("mkdirp")
   , exec = require("./utils/exec.js")
@@ -788,11 +790,24 @@ function addPlacedTarball_ (p, name, uid, gid, cb) {
   var target = path.dirname(p)
     , folder = path.join(target, "package")
 
-  rm(folder, function (er) {
-    if (er) {
-      log.error("addPlacedTarball", "Could not remove %j", folder)
-      return cb(er)
-    }
+  lock(folder, function (er) {
+    if (er) return cb(er)
+    rmUnpack()
+  })
+
+  function rmUnpack () {
+    rm(folder, function (er) {
+      unlock(folder, function () {
+        if (er) {
+          log.error("addPlacedTarball", "Could not remove %j", folder)
+          return cb(er)
+        }
+        thenUnpack()
+      })
+    })
+  }
+
+  function thenUnpack () {
     tar.unpack(p, folder, null, null, uid, gid, function (er) {
       if (er) {
         log.error("addPlacedTarball", "Could not unpack %j to %j", p, target)
@@ -837,7 +852,7 @@ function addPlacedTarball_ (p, name, uid, gid, cb) {
         })
       })
     })
-  })
+  }
 }
 
 function addLocalDirectory (p, name, cb) {

lib/utils/tar.js

@@ -9,6 +9,8 @@ var npm = require("../npm.js")
   , rm = require("rimraf")
   , readJson = require("read-package-json")
   , cache = require("../cache.js")
+  , lock = cache.lock
+  , unlock = cache.unlock
   , myUid = process.getuid && process.getuid()
   , myGid = process.getgid && process.getgid()
   , tar = require("tar")
@@ -43,34 +45,43 @@ function pack (targetTarball, folder, pkg, dfc, cb) {
   }
 }
 
-function pack_ (targetTarball, folder, pkg, cb) {
-  new Packer({ path: folder, type: "Directory", isDirectory: true })
-    .on("error", function (er) {
-      if (er) log.error("tar pack", "Error reading " + folder)
-      return cb(er)
+function pack_ (targetTarball, folder, pkg, cb_) {
+  function cb (er) {
+    unlock(targetTarball, function () {
+      return cb_(er)
     })
+  }
+  lock(targetTarball, function (er) {
+    if (er) return cb(er)
 
-    // By default, npm includes some proprietary attributes in the
-    // package tarball.  This is sane, and allowed by the spec.
-    // However, npm *itself* excludes these from its own package,
-    // so that it can be more easily bootstrapped using old and
-    // non-compliant tar implementations.
-    .pipe(tar.Pack({ noProprietary: !npm.config.get("proprietary-attribs") }))
-    .on("error", function (er) {
-      if (er) log.error("tar.pack", "tar creation error", targetTarball)
-      cb(er)
-    })
-    .pipe(zlib.Gzip())
-    .on("error", function (er) {
-      if (er) log.error("tar.pack", "gzip error "+targetTarball)
-      cb(er)
-    })
-    .pipe(fstream.Writer({ type: "File", path: targetTarball }))
-    .on("error", function (er) {
-      if (er) log.error("tar.pack", "Could not write "+targetTarball)
-      cb(er)
-    })
-    .on("close", cb)
+    new Packer({ path: folder, type: "Directory", isDirectory: true })
+      .on("error", function (er) {
+        if (er) log.error("tar pack", "Error reading " + folder)
+        return cb(er)
+      })
+
+      // By default, npm includes some proprietary attributes in the
+      // package tarball.  This is sane, and allowed by the spec.
+      // However, npm *itself* excludes these from its own package,
+      // so that it can be more easily bootstrapped using old and
+      // non-compliant tar implementations.
+      .pipe(tar.Pack({ noProprietary: !npm.config.get("proprietary-attribs") }))
+      .on("error", function (er) {
+        if (er) log.error("tar.pack", "tar creation error", targetTarball)
+        cb(er)
+      })
+      .pipe(zlib.Gzip())
+      .on("error", function (er) {
+        if (er) log.error("tar.pack", "gzip error "+targetTarball)
+        cb(er)
+      })
+      .pipe(fstream.Writer({ type: "File", path: targetTarball }))
+      .on("error", function (er) {
+        if (er) log.error("tar.pack", "Could not write "+targetTarball)
+        cb(er)
+      })
+      .on("close", cb)
+  })
 }
 
 
@@ -87,13 +98,29 @@ function unpack (tarball, unpackTarget, dMode, fMode, uid, gid, cb) {
   })
 }
 
-function unpack_ ( tarball, unpackTarget, dMode, fMode, uid, gid, cb ) {
+function unpack_ ( tarball, unpackTarget, dMode, fMode, uid, gid, cb_ ) {
   var parent = path.dirname(unpackTarget)
     , base = path.basename(unpackTarget)
 
-  rm(unpackTarget, function (er) {
+  function cb (er) {
+    unlock(unpackTarget, function () {
+      return cb_(er)
+    })
+  }
+
+  lock(unpackTarget, function (er) {
     if (er) return cb(er)
+    rmGunz()
+  })
 
+  function rmGunz () {
+    rm(unpackTarget, function (er) {
+      if (er) return cb(er)
+      gtp()
+    })
+  }
+
+  function gtp () {
     // gzip {tarball} --decompress --stdout \
     //   | tar -mvxpf - --strip-components=1 -C {unpackTarget}
     gunzTarPerm( tarball, unpackTarget
@@ -103,7 +130,7 @@ function unpack_ ( tarball, unpackTarget, dMode, fMode, uid, gid, cb ) {
       if (er) return cb(er)
       readJson(path.resolve(folder, "package.json"), cb)
     })
-  })
+  }
 }