Add a unit test for install_umask.

This test copies a src tree using umask of 002, then runs the build and
install under umask 027. It ensures that the default install_umask of
022 is still applied to all files and directories in the install tree.

run_unittests.py

@@ -2669,6 +2669,74 @@ class LinuxlikeTests(BasePlatformTests):
             # The chown failed nonfatally if we're not root
             self.assertEqual(0, statf.st_uid)
 
+    def test_install_umask(self):
+        '''
+        Test that files are installed with correct permissions using default
+        install umask of 022, regardless of the umask at time the worktree
+        was checked out or the build was executed.
+        '''
+        # Copy source tree to a temporary directory and change permissions
+        # there to simulate a checkout with umask 002.
+        orig_testdir = os.path.join(self.unit_test_dir, '24 install umask')
+        # Create a new testdir under tmpdir.
+        tmpdir = os.path.realpath(tempfile.mkdtemp())
+        self.addCleanup(windows_proof_rmtree, tmpdir)
+        testdir = os.path.join(tmpdir, '24 install umask')
+        # Copy the tree using shutil.copyfile, which will use the current umask
+        # instead of preserving permissions of the old tree.
+        save_umask = os.umask(0o002)
+        self.addCleanup(os.umask, save_umask)
+        shutil.copytree(orig_testdir, testdir, copy_function=shutil.copyfile)
+        # Preserve the executable status of subdir/sayhello though.
+        os.chmod(os.path.join(testdir, 'subdir', 'sayhello'), 0o775)
+        self.init(testdir)
+        # Run the build under a 027 umask now.
+        os.umask(0o027)
+        self.build()
+        # And keep umask 027 for the install step too.
+        self.install()
+
+        for executable in [
+                'bin/prog',
+                'share/subdir/sayhello',
+        ]:
+            f = os.path.join(self.installdir, 'usr', *executable.split('/'))
+            found_mode = stat.filemode(os.stat(f).st_mode)
+            want_mode = '-rwxr-xr-x'
+            self.assertEqual(want_mode, found_mode,
+                             msg=('Expected file %s to have mode %s but found %s instead.' %
+                                  (executable, want_mode, found_mode)))
+
+        for directory in [
+                'usr',
+                'usr/bin',
+                'usr/include',
+                'usr/share',
+                'usr/share/man',
+                'usr/share/man/man1',
+                'usr/share/subdir',
+        ]:
+            f = os.path.join(self.installdir, *directory.split('/'))
+            found_mode = stat.filemode(os.stat(f).st_mode)
+            want_mode = 'drwxr-xr-x'
+            self.assertEqual(want_mode, found_mode,
+                             msg=('Expected directory %s to have mode %s but found %s instead.' %
+                                  (directory, want_mode, found_mode)))
+
+        for datafile in [
+                'include/sample.h',
+                'share/datafile.cat',
+                'share/file.dat',
+                'share/man/man1/prog.1.gz',
+                'share/subdir/datafile.dog',
+        ]:
+            f = os.path.join(self.installdir, 'usr', *datafile.split('/'))
+            found_mode = stat.filemode(os.stat(f).st_mode)
+            want_mode = '-rw-r--r--'
+            self.assertEqual(want_mode, found_mode,
+                             msg=('Expected file %s to have mode %s but found %s instead.' %
+                                  (datafile, want_mode, found_mode)))
+
     def test_cpp_std_override(self):
         testdir = os.path.join(self.unit_test_dir, '6 std override')
         self.init(testdir)

test cases/unit/24 install umask/datafile.cat

@@ -0,0 +1 @@
+Installed cat is installed.

test cases/unit/24 install umask/meson.build

@@ -0,0 +1,7 @@
+project('install umask', 'c')
+executable('prog', 'prog.c', install : true)
+install_headers('sample.h')
+install_man('prog.1')
+install_data('datafile.cat', install_dir : get_option('prefix') + '/share')
+install_subdir('subdir', install_dir : get_option('prefix') + '/share')
+meson.add_install_script('myinstall.py', 'share', 'file.dat')

test cases/unit/24 install umask/myinstall.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+prefix = os.environ['MESON_INSTALL_DESTDIR_PREFIX']
+
+dirname = os.path.join(prefix, sys.argv[1])
+
+try:
+    os.makedirs(dirname)
+except FileExistsError:
+    if not os.path.isdir(dirname):
+        raise
+
+with open(os.path.join(dirname, sys.argv[2]), 'w') as f:
+    f.write('')

test cases/unit/24 install umask/prog.1

@@ -0,0 +1 @@
+Man up, you.

test cases/unit/24 install umask/prog.c

@@ -0,0 +1,3 @@
+int main(int argc, char **arv) {
+    return 0;
+}

test cases/unit/24 install umask/sample.h

@@ -0,0 +1,6 @@
+#ifndef SAMPLE_H
+#define SAMPLE_H
+
+int wackiness();
+
+#endif

test cases/unit/24 install umask/subdir/datafile.dog

@@ -0,0 +1 @@
+Installed dog is installed.

test cases/unit/24 install umask/subdir/sayhello

@@ -0,0 +1,2 @@
+#!/bin/sh
+echo 'Hello, World!'