build: Check if bin script starts with hashbang

PR-URL: https://github.com/npm/npm/pull/16634
Fixes: #12371
Fixes: #13203
Credit: @ScottFreeCode
Reviewed-By: @iarna

3 files changed, 82 insertions, 7 deletions

diff --git a/lib/build.js b/lib/build.js
index 44ac40a00..6a788bc85 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -18,6 +18,8 @@ var link = require('./utils/link.js')
 var linkIfExists = link.ifExists
 var cmdShim = require('cmd-shim')
 var cmdShimIfExists = cmdShim.ifExists
+var isHashbangFile = require('./utils/is-hashbang-file.js')
+var dos2Unix = require('./utils/convert-line-endings.js').dos2Unix
 var asyncMap = require('slide').asyncMap
 var ini = require('ini')
 var writeFile = require('write-file-atomic')
@@ -187,13 +189,18 @@ function linkBins (pkg, folder, parent, gtop, cb) {
           if (er && er.code === 'ENOENT' && npm.config.get('ignore-scripts')) {
             return cb()
           }
-          if (er || !gtop) return cb(er)
-          var dest = path.resolve(binRoot, b)
-          var out = npm.config.get('parseable')
-                  ? dest + '::' + src + ':BINFILE'
-                  : dest + ' -> ' + src
-          if (!npm.config.get('json') && !npm.config.get('parseable')) output(out)
-          cb()
+          if (er) return cb(er)
+          isHashbangFile(src).then((isHashbang) => {
+            if (isHashbang) return dos2Unix(src)
+          }).then(() => {
+            if (!gtop) return cb()
+            var dest = path.resolve(binRoot, b)
+            var out = npm.config.get('parseable')
+                    ? dest + '::' + src + ':BINFILE'
+                    : dest + ' -> ' + src
+            if (!npm.config.get('json') && !npm.config.get('parseable')) output(out)
+            cb()
+          }).catch(cb)
         })
       }
     )
diff --git a/lib/utils/convert-line-endings.js b/lib/utils/convert-line-endings.js
new file mode 100644
index 000000000..b05d328aa
--- /dev/null
+++ b/lib/utils/convert-line-endings.js
@@ -0,0 +1,49 @@
+'use strict'
+
+const Transform = require('stream').Transform
+const Bluebird = require('bluebird')
+const fs = require('graceful-fs')
+const stat = Bluebird.promisify(fs.stat)
+const chmod = Bluebird.promisify(fs.chmod)
+const fsWriteStreamAtomic = require('fs-write-stream-atomic')
+
+module.exports.dos2Unix = dos2Unix
+
+function dos2Unix (file) {
+  return stat(file).then((stats) => {
+    let previousChunkEndedInCR = false
+    return new Bluebird((resolve, reject) => {
+      fs.createReadStream(file)
+        .on('error', reject)
+        .pipe(new Transform({
+          transform: function (chunk, encoding, done) {
+            let data = chunk.toString()
+            if (previousChunkEndedInCR) {
+              data = '\r' + data
+            }
+            if (data[data.length - 1] === '\r') {
+              data = data.slice(0, -1)
+              previousChunkEndedInCR = true
+            } else {
+              previousChunkEndedInCR = false
+            }
+            done(null, data.replace(/\r\n/g, '\n'))
+          },
+          flush: function (done) {
+            if (previousChunkEndedInCR) {
+              this.push('\r')
+            }
+            done()
+          }
+        }))
+        .on('error', reject)
+        .pipe(fsWriteStreamAtomic(file))
+        .on('error', reject)
+        .on('finish', function () {
+          resolve(chmod(file, stats.mode))
+        })
+    })
+  })
+}
+
+// could add unix2Dos and legacy Mac functions if need be
diff --git a/lib/utils/is-hashbang-file.js b/lib/utils/is-hashbang-file.js
new file mode 100644
index 000000000..f1677381f
--- /dev/null
+++ b/lib/utils/is-hashbang-file.js
@@ -0,0 +1,19 @@
+'use strict'
+const Bluebird = require('bluebird')
+const fs = require('graceful-fs')
+const open = Bluebird.promisify(fs.open)
+const close = Bluebird.promisify(fs.close)
+
+module.exports = isHashbangFile
+
+function isHashbangFile (file) {
+  return open(file, 'r').then((fileHandle) => {
+    return new Bluebird((resolve, reject) => {
+      fs.read(fileHandle, new Buffer(new Array(2)), 0, 2, 0, function (err, bytesRead, buffer) {
+        close(fileHandle).then(() => {
+          resolve(!err && buffer.toString() === '#!')
+        }).catch(reject)
+      })
+    })
+  })
+}