Added ReCreate. Also added try catch to api eval of rpc method.

[nodemanager.git] / tools.py

diff --git a/tools.py b/tools.py
index 51527cc..f4496e1 100644 (file)
--- a/tools.py
+++ b/tools.py
@@ -1,14 +1,17 @@
+"""A few things that didn't seem to fit anywhere else."""
+
 import cPickle
 import errno
 import os
 import pwd
 import tempfile
 import threading
+import fcntl
 
 import logger
 
 
-PID_FILE = '/var/run/node_mgr.pid'
+PID_FILE = '/var/run/nm.pid'
 
 def as_daemon_thread(run):
     """Call function <run> with no arguments in its own thread."""
@@ -32,11 +35,10 @@ def daemon():
     os.chdir('/')
     os.umask(0)
     devnull = os.open(os.devnull, os.O_RDWR)
-    for fd in range(3): os.dup2(devnull, fd)
-
-def deepcopy(obj):
-    """Return a deep copy of obj."""
-    return cPickle.loads(cPickle.dumps(obj, -1))
+    os.dup2(devnull, 0)
+    crashlog = os.open('/root/nm.stderr', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
+    os.dup2(crashlog, 1)
+    os.dup2(crashlog, 2)
 
 def fork_as(su, function, *args):
     """fork(), cd / to avoid keeping unused directories open, close all nonstandard file descriptors (to avoid capturing open sockets), fork() again (to avoid zombies) and call <function> with arguments <args> in the grandchild process.  If <su> is not None, set our group and user ids appropriately in the child process."""
@@ -45,9 +47,10 @@ def fork_as(su, function, *args):
         try:
             os.chdir('/')
             close_nonstandard_fds()
-            pw_ent = pwd.getpwnam(su)
-            os.setegid(pw_ent[3])
-            os.seteuid(pw_ent[2])
+            if su:
+                pw_ent = pwd.getpwnam(su)
+                os.setegid(pw_ent[3])
+                os.seteuid(pw_ent[2])
             child_pid = os.fork()
             if child_pid == 0: function(*args)
         except:
@@ -74,13 +77,29 @@ def pid_file():
         write_file(PID_FILE, lambda f: f.write(str(os.getpid())))
     return other_pid
 
-def write_file(filename, do_write):
+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), filename)
+    os.rename(write_temp_file(do_write, **kw_args), filename)
 
-def write_temp_file(do_write):
+def write_temp_file(do_write, mode=None, uidgid=None):
     fd, temporary_filename = tempfile.mkstemp()
+    if mode: os.chmod(temporary_filename, mode)
+    if uidgid: os.chown(temporary_filename, *uidgid)
     f = os.fdopen(fd, 'w')
     try: do_write(f)
     finally: f.close()
     return temporary_filename
+
+
+class NMLock:
+    def __init__(self, file):
+        self.fd = os.open(file, os.O_RDWR|os.O_CREAT, 0600)
+        flags = fcntl.fcntl(self.fd, fcntl.F_GETFD)
+        flags |= fcntl.FD_CLOEXEC
+        fcntl.fcntl(self.fd, fcntl.F_SETFD, flags)
+    def __del__(self):
+        os.close(self.fd)
+    def acquire(self):
+        fcntl.lockf(self.fd, fcntl.LOCK_EX)
+    def release(self):
+        fcntl.lockf(self.fd, fcntl.LOCK_UN)