From de0b93f912f014155423ed9a679dcd99c40f2622 Mon Sep 17 00:00:00 2001
From: Maxim Belkin <maxim.belkin@gmail.com>
Date: Tue, 7 Nov 2017 14:18:25 -0600
Subject: [PATCH] pathname: improvements, cleanups, and new methods

- atomic_write: close file before renaming to prevent error:
  'Device or resource busy'
- ensure_writable: preserve executable bit
- new elf? and dynamic? methods
---
 .../extend/os/linux/extend/pathname.rb        | 19 +++++++++++++++++++
 .../mac => extend/os/mac/extend}/pathname.rb  |  0
 .../Homebrew/extend/os/mac/hardware/cpu.rb    |  2 --
 Library/Homebrew/extend/os/pathname.rb        |  5 +++++
 Library/Homebrew/extend/pathname.rb           |  7 ++++++-
 Library/Homebrew/os/mac.rb                    |  1 -
 6 files changed, 30 insertions(+), 4 deletions(-)
 create mode 100644 Library/Homebrew/extend/os/linux/extend/pathname.rb
 rename Library/Homebrew/{os/mac => extend/os/mac/extend}/pathname.rb (100%)
 create mode 100644 Library/Homebrew/extend/os/pathname.rb

diff --git a/Library/Homebrew/extend/os/linux/extend/pathname.rb b/Library/Homebrew/extend/os/linux/extend/pathname.rb
new file mode 100644
index 0000000000..eb6ea409bc
--- /dev/null
+++ b/Library/Homebrew/extend/os/linux/extend/pathname.rb
@@ -0,0 +1,19 @@
+class Pathname
+  # @private
+  def elf?
+    # See: https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#File_header
+    read(4) == "\x7fELF"
+  end
+
+  # @private
+  def dynamic_elf?
+    if which "readelf"
+      popen_read("readelf", "-l", to_path).include?(" DYNAMIC ")
+    elsif which "file"
+      !popen_read("file", "-L", "-b", to_path)[/dynamic|shared/].nil?
+    else
+      raise StandardError, "Neither `readelf` nor `file` is available "\
+        "to determine whether '#{self}' is dynamically or statically linked."
+    end
+  end
+end
diff --git a/Library/Homebrew/os/mac/pathname.rb b/Library/Homebrew/extend/os/mac/extend/pathname.rb
similarity index 100%
rename from Library/Homebrew/os/mac/pathname.rb
rename to Library/Homebrew/extend/os/mac/extend/pathname.rb
diff --git a/Library/Homebrew/extend/os/mac/hardware/cpu.rb b/Library/Homebrew/extend/os/mac/hardware/cpu.rb
index b97c280cd2..a216db6ae1 100644
--- a/Library/Homebrew/extend/os/mac/hardware/cpu.rb
+++ b/Library/Homebrew/extend/os/mac/hardware/cpu.rb
@@ -1,5 +1,3 @@
-require "os/mac/pathname"
-
 module Hardware
   class CPU
     class << self
diff --git a/Library/Homebrew/extend/os/pathname.rb b/Library/Homebrew/extend/os/pathname.rb
new file mode 100644
index 0000000000..5e6edeb309
--- /dev/null
+++ b/Library/Homebrew/extend/os/pathname.rb
@@ -0,0 +1,5 @@
+if OS.mac?
+  require "extend/os/mac/extend/pathname"
+elsif OS.linux?
+  require "extend/os/linux/extend/pathname"
+end
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index b4c7ca9595..82cf10be07 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -189,6 +189,9 @@ class Pathname
       rescue Errno::EPERM # rubocop:disable Lint/HandleExceptions
       end
 
+      # Close the file before renaming to prevent the error: Device or resource busy
+      # Affects primarily NFS.
+      tf.close
       File.rename(tf.path, self)
     ensure
       tf.close!
@@ -376,7 +379,7 @@ class Pathname
     saved_perms = nil
     unless writable_real?
       saved_perms = stat.mode
-      chmod 0644
+      FileUtils.chmod "u+rw", to_path
     end
     yield
   ensure
@@ -469,6 +472,8 @@ class Pathname
   end
 end
 
+require "extend/os/pathname"
+
 # @private
 module ObserverPathnameExtension
   class << self
diff --git a/Library/Homebrew/os/mac.rb b/Library/Homebrew/os/mac.rb
index cb4141f489..a5e12c9248 100644
--- a/Library/Homebrew/os/mac.rb
+++ b/Library/Homebrew/os/mac.rb
@@ -3,7 +3,6 @@ require "development_tools"
 require "os/mac/version"
 require "os/mac/xcode"
 require "os/mac/xquartz"
-require "os/mac/pathname"
 require "os/mac/sdk"
 require "os/mac/keg"