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.

1 files changed, 103 insertions, 1 deletions

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.')