[Kimchi-devel] [PATCH V4] add a method to fix search permissions

[shaohef at linux.vnet.ibm.com]

From: ShaoHe Feng <shaohef at linux.vnet.ibm.com>

First will use setfacl to set the path search permission for user or
group, if failed then set search permission for others on the path.

Usage:
check_path_permission("/tmp/need/to/fix/path", username)
fix_path_permission("/tmp/need/to/fix/path", username)

Signed-off-by: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
Signed-off-by: Royce Lv <lvroyce at linux.vnet.ibm.com>
---
 Makefile.am         |  1 +
 src/kimchi/utils.py | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/Makefile.am b/Makefile.am
index 07b2aa0..bf8e0a0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -46,6 +46,7 @@ PEP8_WHITELIST = \
 	src/kimchi/cachebust.py \
 	src/kimchi/config.py.in \
 	src/kimchi/control/*.py \
+	src/kimchi/utils.py \
 	src/kimchi/disks.py \
 	src/kimchi/featuretests.py \
 	src/kimchi/iscsi.py \
diff --git a/src/kimchi/utils.py b/src/kimchi/utils.py
index b6d84fd..bfb5836 100644
--- a/src/kimchi/utils.py
+++ b/src/kimchi/utils.py
@@ -18,11 +18,15 @@
 #
 # You should have received a copy of the GNU Lesser General Public
 # License along with this library; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 #
 
 import cherrypy
 import os
+import pwd
+import re
+import stat
+import subprocess
 
 
 from cherrypy.lib.reprconf import Parser
@@ -33,6 +37,7 @@ from kimchi import config
 
 kimchi_log = cherrypy.log.error_log
 
+
 def is_digit(value):
     if isinstance(value, int):
         return True
@@ -84,3 +89,91 @@ def import_class(class_path):
 
 def import_module(module_name):
     return __import__(module_name, globals(), locals(), [''])
+
+
+def name_uid(user):
+    return pwd.getpwnam(user).pw_uid
+
+
+def run_command(cmd):
+    try:
+        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+                                stderr=subprocess.PIPE)
+        out, error = proc.communicate()
+
+        kimchi_log.debug("Run command '%s'", " ".join(cmd))
+        if out or error:
+            kimchi_log.debug("out:\n %s\nerror:\n %s", out, error)
+    except OSError:
+        kimchi_log.debug("Failed to run command %s", " ".join(cmd))
+        return (None, None, None)
+    if proc.returncode != 0:
+        kimchi_log.debug("Cmd '%s' failed, error code: %s", cmd, error)
+    return (out, error, proc.returncode)
+
+
+def run_setfacl_set_x(path, user="qemu", group=None):
+    set_user = ["setfacl", "--modify", "user:%s:x" % user, path]
+    set_group = ["setfacl", "--modify", "group:%s:x" % group, path]
+    out, error, ret = run_command(set_user)
+    if ret != 0 and group:
+        out, error, ret = run_command(set_group)
+    return ret == 0
+
+
+def run_getfacl(path, user="qemu", group=None):
+    cmd = ["getfacl", path]
+    out, error, ret = run_command(cmd)
+    if out and ret == 0:
+        res = re.findall("user:%s:..x" % user, out)
+        res = re.findall("group:%s:..x" % group,
+                         out) if group and not res else res
+        return res != []
+    return False
+
+
+def set_x_on_path(path, who="other"):
+    S_IXWHO = ((stat.S_IXUSR if who == "user" else None) or
+               (stat.S_IXGRP if who == "group" else None) or
+               stat.S_IXOTH)
+    mode = os.stat(path).st_mode | S_IXWHO
+    os.chmod(path, mode)
+    ret = os.stat(path).st_mode == mode
+    if not ret:
+        kimchi_log.debug("faild to set +x attribute on %s", path)
+    return ret
+
+
+def get_x_on_path(path, uid):
+    try:
+        info = os.stat(path)
+        mode = info.st_mode
+        return ((uid == info.st_uid and mode & stat.S_IXUSR == stat.S_IXUSR) or
+                (uid == info.st_gid and mode & stat.S_IXGRP == stat.S_IXGRP) or
+                mode & stat.S_IXGRP == stat.S_IXOTH)
+    except OSError:
+        kimchi_log.debug("faild to get attribute on %s as user id: %s",
+                         path, uid)
+        return False
+
+
+def check_path_permission(path, user='qemu', group=None):
+    return get_x_on_path(path,
+                         name_uid(user)) or run_getfacl(path, user, group)
+
+
+def fix_path_permission(path, user='qemu'):
+    paths = []
+    while path:
+        paths.append(path)
+        if path == "/":
+            break
+        path = os.path.dirname(path)
+
+    paths.reverse()
+    for path in paths:
+        if not (check_path_permission(path) or
+                run_setfacl_set_x(path) or
+                set_x_on_path(path)):
+            return False
+    return True
-- 
1.8.4.2