X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=tools.py;h=36754fc9fc45547c766555d72fcce55107d1270e;hb=55afbcaa2f8e9646bec3962e406f150f5d31b47b;hp=98a5b7e3f163541fff9af4db2c1c1cb91c903b93;hpb=2306328a4623d578e93bd59982623908eb8742dd;p=nodemanager.git

diff --git a/tools.py b/tools.py
index 98a5b7e..36754fc 100644
--- a/tools.py
+++ b/tools.py
@@ -1,15 +1,13 @@
-# $Id$
-# $URL$
-
 """A few things that didn't seem to fit anywhere else."""
 
-import os
+import os, os.path
 import pwd
 import tempfile
 import fcntl
 import errno
 import threading
 import subprocess
+import shutil
 
 import logger
 
@@ -60,7 +58,7 @@ def daemon():
     os.setsid()
     if os.fork() != 0: os._exit(0)
     os.chdir('/')
-    os.umask(0)
+    os.umask(0022)
     devnull = os.open(os.devnull, os.O_RDWR)
     os.dup2(devnull, 0)
     # xxx fixme - this is just to make sure that nothing gets stupidly lost - should use devnull
@@ -91,8 +89,8 @@ def fork_as(su, function, *args):
 ####################
 # manage files
 def pid_file():
-    """We use a pid file to ensure that only one copy of NM is running at a given time.  
-If successful, this function will write a pid file containing the pid of the current process.  
+    """We use a pid file to ensure that only one copy of NM is running at a given time.
+If successful, this function will write a pid file containing the pid of the current process.
 The return value is the pid of the other running process, or None otherwise."""
     other_pid = None
     if os.access(PID_FILE, os.F_OK):  # check for a pid file
@@ -111,7 +109,7 @@ The return value is the pid of the other running process, or None otherwise."""
 
 def write_file(filename, do_write, **kw_args):
     """Write file <filename> atomically by opening a temporary file, using <do_write> to write that file, and then renaming the temporary file."""
-    os.rename(write_temp_file(do_write, **kw_args), filename)
+    shutil.move(write_temp_file(do_write, **kw_args), filename)
 
 def write_temp_file(do_write, mode=None, uidgid=None):
     fd, temporary_filename = tempfile.mkstemp()
@@ -123,25 +121,35 @@ def write_temp_file(do_write, mode=None, uidgid=None):
     return temporary_filename
 
 # replace a target file with a new contents - checks for changes
-# return True if a change occurred, in which case
-# chown/chmod settings should be taken care of
-def replace_file_with_string (target, new_contents):
+# can handle chmod if requested
+# can also remove resulting file if contents are void, if requested
+# performs atomically:
+#    writes in a tmp file, which is then renamed (from sliverauth originally)
+# returns True if a change occurred, or the file is deleted
+def replace_file_with_string (target, new_contents, chmod=None, remove_if_empty=False):
     try:
         current=file(target).read()
     except:
         current=""
-    # xxx if verbose, report diffs...
     if current==new_contents:
+        # if turns out to be an empty string, and remove_if_empty is set,
+        # then make sure to trash the file if it exists
+        if remove_if_empty and not new_contents and os.path.isfile(target):
+            logger.verbose("tools.replace_file_with_string: removing file %s"%target)
+            try: os.unlink(target)
+            finally: return True
         return False
-    # overwrite target file
-    f=file(target,'w')
-    f.write(new_contents)
-    f.close()
+    # overwrite target file: create a temp in the same directory
+    path=os.path.dirname(target) or '.'
+    fd, name = tempfile.mkstemp('','repl',path)
+    os.write(fd,new_contents)
+    os.close(fd)
+    if os.path.exists(target):
+        os.unlink(target)
+    shutil.move(name,target)
+    if chmod: os.chmod(target,chmod)
     return True
 
-# not needed yet - should that unlink the new file ?
-#def replace_file_with_file (target, new):
-#    return replace_file_with_string (target, file(new).read())
 
 ####################
 # utilities functions to get (cached) information from the node