Support file perms for install_data and install_subdir

With the 'install_mode' kwarg, you can now specify the file and
directory permissions and the owner and the group to be used while
installing. You can pass either:

* A single string specifying just the permissions
* A list of strings with:
  - The first argument a string of permissions
  - The second argument a string specifying the owner or
    an int specifying the uid
  - The third argument a string specifying the group or
    an int specifying the gid

Specifying `false` as any of the arguments skips setting that one.

The format of the permissions kwarg is the same as the symbolic
notation used by ls -l with the first character that specifies 'd',
'-', 'c', etc for the file type omitted since that is always obvious
from the context.

Includes unit tests for the same. Sadly these only run on Linux right
now, but we want them to run on all platforms. We do set the mode in the
integration tests for all platforms but we don't check if they were
actually set correctly.

6 files changed, 169 insertions, 13 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index e46c2c5..6f8a50e 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -459,7 +459,8 @@ class Backend:
         mfobj['projects'] = self.build.dep_manifest
         with open(ifilename, 'w') as f:
             f.write(json.dumps(mfobj))
-        d.data.append([ifilename, ofilename])
+        # Copy file from, to, and with mode unchanged
+        d.data.append([ifilename, ofilename, None])
 
     def get_regen_filelist(self):
         '''List of all files whose alteration means that the build
diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index e1a478c..628718f 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -700,7 +700,7 @@ int dummy;
                 assert(isinstance(f, mesonlib.File))
                 plain_f = os.path.split(f.fname)[1]
                 dstabs = os.path.join(subdir, plain_f)
-                i = [f.absolute_path(srcdir, builddir), dstabs]
+                i = [f.absolute_path(srcdir, builddir), dstabs, de.install_mode]
                 d.data.append(i)
 
     def generate_subdir_install(self, d):
@@ -715,7 +715,7 @@ int dummy;
                 inst_dir = sd.installable_subdir
             src_dir = os.path.join(self.environment.get_source_dir(), subdir)
             dst_dir = os.path.join(self.environment.get_prefix(), sd.install_dir)
-            d.install_subdirs.append([src_dir, inst_dir, dst_dir])
+            d.install_subdirs.append([src_dir, inst_dir, dst_dir, sd.install_mode])
 
     def generate_tests(self, outfile):
         self.serialise_tests()
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index ceae49b..dc072a5 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -1502,9 +1502,10 @@ class ConfigurationData:
 # A bit poorly named, but this represents plain data files to copy
 # during install.
 class Data:
-    def __init__(self, sources, install_dir):
+    def __init__(self, sources, install_dir, install_mode=None):
         self.sources = sources
         self.install_dir = install_dir
+        self.install_mode = install_mode
         if not isinstance(self.sources, list):
             self.sources = [self.sources]
         for s in self.sources:
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index b5cd0b6..cb5b617 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -22,7 +22,7 @@ from . import optinterpreter
 from . import compilers
 from .wrap import wrap
 from . import mesonlib
-from .mesonlib import Popen_safe
+from .mesonlib import FileMode, Popen_safe
 from .dependencies import InternalDependency, Dependency
 from .interpreterbase import InterpreterBase
 from .interpreterbase import check_stringlist, noPosargs, noKwargs, stringArgs
@@ -453,11 +453,12 @@ class DataHolder(InterpreterObject):
         return self.held_object.install_dir
 
 class InstallDir(InterpreterObject):
-    def __init__(self, source_subdir, installable_subdir, install_dir):
+    def __init__(self, src_subdir, inst_subdir, install_dir, install_mode):
         InterpreterObject.__init__(self)
-        self.source_subdir = source_subdir
-        self.installable_subdir = installable_subdir
+        self.source_subdir = src_subdir
+        self.installable_subdir = inst_subdir
         self.install_dir = install_dir
+        self.install_mode = install_mode
 
 class Man(InterpreterObject):
 
@@ -2141,6 +2142,25 @@ requirements use the version keyword argument instead.''')
         self.evaluate_codeblock(codeblock)
         self.subdir = prev_subdir
 
+    def _get_kwarg_install_mode(self, kwargs):
+        if 'install_mode' not in kwargs:
+            return None
+        install_mode = []
+        mode = mesonlib.stringintlistify(kwargs.get('install_mode', []))
+        for m in mode:
+            # We skip any arguments that are set to `false`
+            if m is False:
+                m = None
+            install_mode.append(m)
+        if len(install_mode) > 3:
+            raise InvalidArguments('Keyword argument install_mode takes at '
+                                   'most 3 arguments.')
+        if len(install_mode) > 0 and install_mode[0] is not None and \
+           not isinstance(install_mode[0], str):
+            raise InvalidArguments('Keyword argument install_mode requires the '
+                                   'permissions arg to be a string or false')
+        return FileMode(*install_mode)
+
     def func_install_data(self, node, args, kwargs):
         kwsource = mesonlib.stringlistify(kwargs.get('sources', []))
         raw_sources = args + kwsource
@@ -2153,7 +2173,10 @@ requirements use the version keyword argument instead.''')
                 source_strings.append(s)
         sources += self.source_strings_to_files(source_strings)
         install_dir = kwargs.get('install_dir', None)
-        data = DataHolder(build.Data(sources, install_dir))
+        if not isinstance(install_dir, (str, type(None))):
+            raise InvalidArguments('Keyword argument install_dir not a string.')
+        install_mode = self._get_kwarg_install_mode(kwargs)
+        data = DataHolder(build.Data(sources, install_dir, install_mode))
         self.build.data.append(data.held_object)
         return data
 
@@ -2166,7 +2189,8 @@ requirements use the version keyword argument instead.''')
         install_dir = kwargs['install_dir']
         if not isinstance(install_dir, str):
             raise InvalidArguments('Keyword argument install_dir not a string.')
-        idir = InstallDir(self.subdir, args[0], install_dir)
+        install_mode = self._get_kwarg_install_mode(kwargs)
+        idir = InstallDir(self.subdir, args[0], install_dir, install_mode)
         self.build.install_dirs.append(idir)
         return idir
 
diff --git a/mesonbuild/mesonlib.py b/mesonbuild/mesonlib.py
index 2587d6f..2ad43c8 100644
--- a/mesonbuild/mesonlib.py
+++ b/mesonbuild/mesonlib.py
@@ -14,6 +14,7 @@
 
 """A library of random helper functionality."""
 
+import stat
 import platform, subprocess, operator, os, shutil, re
 
 from glob import glob
@@ -24,6 +25,97 @@ class MesonException(Exception):
 class EnvironmentException(MesonException):
     '''Exceptions thrown while processing and creating the build environment'''
 
+class FileMode:
+    # The first triad is for owner permissions, the second for group permissions,
+    # and the third for others (everyone else).
+    # For the 1st character:
+    #  'r' means can read
+    #  '-' means not allowed
+    # For the 2nd character:
+    #  'w' means can write
+    #  '-' means not allowed
+    # For the 3rd character:
+    #  'x' means can execute
+    #  's' means can execute and setuid/setgid is set (owner/group triads only)
+    #  'S' means cannot execute and setuid/setgid is set (owner/group triads only)
+    #  't' means can execute and sticky bit is set ("others" triads only)
+    #  'T' means cannot execute and sticky bit is set ("others" triads only)
+    #  '-' means none of these are allowed
+    #
+    # The meanings of 'rwx' perms is not obvious for directories; see:
+    # https://www.hackinglinuxexposed.com/articles/20030424.html
+    #
+    # For information on this notation such as setuid/setgid/sticky bits, see:
+    # https://en.wikipedia.org/wiki/File_system_permissions#Symbolic_notation
+    symbolic_perms_regex = re.compile('[r-][w-][xsS-]' # Owner perms
+                                      '[r-][w-][xsS-]' # Group perms
+                                      '[r-][w-][xtT-]') # Others perms
+
+    def __init__(self, perms=None, owner=None, group=None):
+        self.perms_s = perms
+        self.perms = self.perms_s_to_bits(perms)
+        self.owner = owner
+        self.group = group
+
+    def __repr__(self):
+        ret = '<FileMode: {!r} owner={} group={}'
+        return ret.format(self.perms_s, self.owner, self.group)
+
+    @classmethod
+    def perms_s_to_bits(cls, perms_s):
+        '''
+        Does the opposite of stat.filemode(), converts strings of the form
+        'rwxr-xr-x' to st_mode enums which can be passed to os.chmod()
+        '''
+        if perms_s is None:
+            # No perms specified, we will not touch the permissions
+            return -1
+        eg = 'rwxr-xr-x'
+        if not isinstance(perms_s, str):
+            msg = 'Install perms must be a string. For example, {!r}'
+            raise MesonException(msg.format(eg))
+        if len(perms_s) != 9 or not cls.symbolic_perms_regex.match(perms_s):
+            msg = 'File perms {!r} must be exactly 9 chars. For example, {!r}'
+            raise MesonException(msg.format(perms_s, eg))
+        perms = 0
+        # Owner perms
+        if perms_s[0] == 'r':
+            perms |= stat.S_IRUSR
+        if perms_s[1] == 'w':
+            perms |= stat.S_IWUSR
+        if perms_s[2] == 'x':
+            perms |= stat.S_IXUSR
+        elif perms_s[2] == 'S':
+            perms |= stat.S_ISUID
+        elif perms_s[2] == 's':
+            perms |= stat.S_IXUSR
+            perms |= stat.S_ISUID
+        # Group perms
+        if perms_s[3] == 'r':
+            perms |= stat.S_IRGRP
+        if perms_s[4] == 'w':
+            perms |= stat.S_IWGRP
+        if perms_s[5] == 'x':
+            perms |= stat.S_IXGRP
+        elif perms_s[5] == 'S':
+            perms |= stat.S_ISGID
+        elif perms_s[5] == 's':
+            perms |= stat.S_IXGRP
+            perms |= stat.S_ISGID
+        # Others perms
+        if perms_s[6] == 'r':
+            perms |= stat.S_IROTH
+        if perms_s[7] == 'w':
+            perms |= stat.S_IWOTH
+        if perms_s[8] == 'x':
+            perms |= stat.S_IXOTH
+        elif perms_s[8] == 'T':
+            perms |= stat.S_ISVTX
+        elif perms_s[8] == 't':
+            perms |= stat.S_IXOTH
+            perms |= stat.S_ISVTX
+        return perms
+
 class File:
     def __init__(self, is_built, subdir, fname):
         self.is_built = is_built
@@ -360,11 +452,21 @@ def replace_if_different(dst, dst_tmp):
     else:
         os.unlink(dst_tmp)
 
+def stringintlistify(item):
+    if isinstance(item, (str, int)):
+        item = [item]
+    if not isinstance(item, list):
+        raise MesonException('Item must be a list, a string, or an int')
+    for i in item:
+        if not isinstance(i, (str, int, type(None))):
+            raise MesonException('List item must be a string or an int')
+    return item
+
 def stringlistify(item):
     if isinstance(item, str):
         item = [item]
     if not isinstance(item, list):
-        raise MesonException('Item is not an array')
+        raise MesonException('Item is not a list')
     for i in item:
         if not isinstance(i, str):
             raise MesonException('List item not a string.')
diff --git a/mesonbuild/scripts/meson_install.py b/mesonbuild/scripts/meson_install.py
index 676a1e5..a74573e 100644
--- a/mesonbuild/scripts/meson_install.py
+++ b/mesonbuild/scripts/meson_install.py
@@ -16,10 +16,34 @@ import sys, pickle, os, shutil, subprocess, gzip, platform
 from glob import glob
 from . import depfixer
 from . import destdir_join
-from ..mesonlib import Popen_safe
+from ..mesonlib import is_windows, Popen_safe
 
 install_log_file = None
 
+def set_mode(path, mode):
+    if mode is None:
+        # Keep mode unchanged
+        return
+    if (mode.perms_s or mode.owner or mode.group) is None:
+        # Nothing to set
+        return
+    # No chown() on Windows, and must set one of owner/group
+    if not is_windows() and (mode.owner or mode.group) is not None:
+        try:
+            shutil.chown(path, mode.owner, mode.group)
+        except PermissionError as e:
+            msg = '{!r}: Unable to set owner {!r} and group {!r}: {}, ignoring...'
+            print(msg.format(path, mode.owner, mode.group, e.strerror))
+    # Must set permissions *after* setting owner/group otherwise the
+    # setuid/setgid bits will get wiped by chmod
+    # NOTE: On Windows you can set read/write perms; the rest are ignored
+    if mode.perms_s is not None:
+        try:
+            os.chmod(path, mode.perms)
+        except PermissionError as e:
+            msg = '{!r}: Unable to set permissions {!r}: {}, ignoring...'
+            print(msg.format(path, mode.perms_s, e.strerror))
+
 def append_to_log(line):
     install_log_file.write(line)
     if not line.endswith('\n'):
@@ -96,7 +120,7 @@ def do_install(datafilename):
     run_install_script(d)
 
 def install_subdirs(data):
-    for (src_dir, inst_dir, dst_dir) in data.install_subdirs:
+    for (src_dir, inst_dir, dst_dir, mode) in data.install_subdirs:
         if src_dir.endswith('/') or src_dir.endswith('\\'):
             src_dir = src_dir[:-1]
         src_prefix = os.path.join(src_dir, inst_dir)
@@ -105,15 +129,19 @@ def install_subdirs(data):
         if not os.path.exists(dst_dir):
             os.makedirs(dst_dir)
         do_copydir(src_prefix, src_dir, dst_dir)
+        dst_prefix = os.path.join(dst_dir, inst_dir)
+        set_mode(dst_prefix, mode)
 
 def install_data(d):
     for i in d.data:
         fullfilename = i[0]
         outfilename = get_destdir_path(d, i[1])
+        mode = i[2]
         outdir = os.path.split(outfilename)[0]
         os.makedirs(outdir, exist_ok=True)
         print('Installing %s to %s.' % (fullfilename, outdir))
         do_copyfile(fullfilename, outfilename)
+        set_mode(outfilename, mode)
 
 def install_man(d):
     for m in d.man: