lib: implemented oe.path.realpath()
Various parts of the buildsystem have to work with symlinks. Resolving them is not trivial because they are always relative to a sysroot directory. Patch adds a function which returns the destination of a symlink by assuming a given path as the / toplevel directory. A testsuite was added too. (From OE-Core rev: 76e0bd7f8e3a3bd052a6e329f88e2d8099e899c4) Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Enrico Scholz
Richard Purdie
parent
f2e16c6552
commit
21b6ff9bc3
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@ -2,6 +2,7 @@ import errno
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import glob
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import shutil
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import subprocess
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import os.path
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def join(*paths):
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"""Like os.path.join but doesn't treat absolute RHS specially"""
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@ -161,3 +162,89 @@ def find(dir, **walkoptions):
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for root, dirs, files in os.walk(dir, **walkoptions):
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for file in files:
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yield os.path.join(root, file)
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## realpath() related functions
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def __is_path_below(file, root):
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return (file + os.path.sep).startswith(root)
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def __realpath_rel(start, rel_path, root, loop_cnt):
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"""Calculates real path of symlink 'start' + 'rel_path' below
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'root'; no part of 'start' below 'root' must contain symlinks. """
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have_dir = True
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for d in rel_path.split(os.path.sep):
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if not have_dir:
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raise OSError(errno.ENOENT, "no such directory %s" % start)
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if d == os.path.pardir: # '..'
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if len(start) >= len(root):
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# do not follow '..' before root
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start = os.path.dirname(start)
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else:
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# emit warning?
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pass
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else:
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(start, have_dir) = __realpath(os.path.join(start, d),
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root, loop_cnt)
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assert(__is_path_below(start, root))
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return start
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def __realpath(file, root, loop_cnt):
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while os.path.islink(file) and len(file) >= len(root):
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if loop_cnt == 0:
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raise OSError(errno.ELOOP, file)
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loop_cnt -= 1
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target = os.path.normpath(os.readlink(file))
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if not os.path.isabs(target):
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tdir = os.path.dirname(file)
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assert(__is_path_below(tdir, root))
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else:
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tdir = root
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file = __realpath_rel(tdir, target, root, loop_cnt)
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try:
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is_dir = os.path.isdir(file)
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except:
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is_dir = false
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return (file, is_dir)
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def realpath(file, root, use_physdir = True, loop_cnt = 100):
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""" Returns the canonical path of 'file' with assuming a toplevel
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'root' directory. When 'use_physdir' is set, all preceding path
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components of 'file' will be resolved first; this flag should be
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set unless it is guaranteed that there is no symlink in the path."""
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root = os.path.normpath(root)
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file = os.path.normpath(file)
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if not root.endswith(os.path.sep):
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# letting root end with '/' makes some things easier
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root = root + os.path.sep
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if not __is_path_below(file, root):
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raise OSError(errno.EINVAL, "file '%s' is not below root" % file)
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try:
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if use_physdir:
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file = __realpath_rel(root, file[(len(root) - 1):], root, loop_cnt)
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else:
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file = __realpath(file, root, loop_cnt)[0]
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except OSError, e:
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if e.errno == errno.ELOOP:
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# make ELOOP more readable; without catching it, there will
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# be printed a backtrace with 100s of OSError exceptions
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# else
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raise OSError(errno.ELOOP,
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"too much recursions while resolving '%s'; loop in '%s'" %
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(file, e.strerror))
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raise
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return file
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@ -0,0 +1,89 @@
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import unittest
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import oe, oe.path
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import tempfile
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import os
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import errno
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import shutil
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class TestRealPath(unittest.TestCase):
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DIRS = [ "a", "b", "etc", "sbin", "usr", "usr/bin", "usr/binX", "usr/sbin", "usr/include", "usr/include/gdbm" ]
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FILES = [ "etc/passwd", "b/file" ]
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LINKS = [
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( "bin", "/usr/bin", "/usr/bin" ),
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( "binX", "usr/binX", "/usr/binX" ),
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( "c", "broken", "/broken" ),
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( "etc/passwd-1", "passwd", "/etc/passwd" ),
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( "etc/passwd-2", "passwd-1", "/etc/passwd" ),
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( "etc/passwd-3", "/etc/passwd-1", "/etc/passwd" ),
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( "etc/shadow-1", "/etc/shadow", "/etc/shadow" ),
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( "etc/shadow-2", "/etc/shadow-1", "/etc/shadow" ),
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( "prog-A", "bin/prog-A", "/usr/bin/prog-A" ),
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( "prog-B", "/bin/prog-B", "/usr/bin/prog-B" ),
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( "usr/bin/prog-C", "../../sbin/prog-C", "/sbin/prog-C" ),
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( "usr/bin/prog-D", "/sbin/prog-D", "/sbin/prog-D" ),
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( "usr/binX/prog-E", "../sbin/prog-E", None ),
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( "usr/bin/prog-F", "../../../sbin/prog-F", "/sbin/prog-F" ),
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( "loop", "a/loop", None ),
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( "a/loop", "../loop", None ),
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( "b/test", "file/foo", None ),
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]
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LINKS_PHYS = [
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( "./", "/", "" ),
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( "binX/prog-E", "/usr/sbin/prog-E", "/sbin/prog-E" ),
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]
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EXCEPTIONS = [
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( "loop", errno.ELOOP ),
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( "b/test", errno.ENOENT ),
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]
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def __del__(self):
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try:
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#os.system("tree -F %s" % self.tmpdir)
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shutil.rmtree(self.tmpdir)
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except:
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pass
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def setUp(self):
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self.tmpdir = tempfile.mkdtemp(prefix = "oe-test_path")
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self.root = os.path.join(self.tmpdir, "R")
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os.mkdir(os.path.join(self.tmpdir, "_real"))
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os.symlink("_real", self.root)
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for d in self.DIRS:
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os.mkdir(os.path.join(self.root, d))
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for f in self.FILES:
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file(os.path.join(self.root, f), "w")
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for l in self.LINKS:
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os.symlink(l[1], os.path.join(self.root, l[0]))
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def __realpath(self, file, use_physdir):
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return oe.path.realpath(os.path.join(self.root, file), self.root, use_physdir)
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def test_norm(self):
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for l in self.LINKS:
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if l[2] == None:
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continue
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target_p = self.__realpath(l[0], True)
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target_l = self.__realpath(l[0], False)
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if l[2] != False:
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self.assertEqual(target_p, target_l)
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self.assertEqual(l[2], target_p[len(self.root):])
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def test_phys(self):
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for l in self.LINKS_PHYS:
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target_p = self.__realpath(l[0], True)
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target_l = self.__realpath(l[0], False)
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self.assertEqual(l[1], target_p[len(self.root):])
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self.assertEqual(l[2], target_l[len(self.root):])
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def test_loop(self):
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for e in self.EXCEPTIONS:
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self.assertRaisesRegexp(OSError, r'\[Errno %u\]' % e[1],
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self.__realpath, e[0], False)
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