X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=tools.py;h=199d799def48edac009eae07c93f02133f922676;hb=755be0fb0adb034ea9879167ed30256d3d19eca6;hp=f3e67e1595a185c907799d93f1f851526b084282;hpb=4293a16c3c0badbc130c3af6b62c3681a5eeb9d6;p=nodemanager.git

diff --git a/tools.py b/tools.py
index f3e67e1..199d799 100644
--- a/tools.py
+++ b/tools.py
@@ -9,10 +9,6 @@ import threading
 import fcntl
 import commands
 import logger
-try:
-   import sioc
-except:
-   pass
 
 PID_FILE = '/var/run/nm.pid'
 
@@ -22,12 +18,16 @@ def get_default_if():
     return interface
 
 def get_hwaddr_from_plnode():
-    for line in open("/usr/boot/plnode.txt", 'r').readlines():
-        if line.startswith("NET_DEVICE"):
-            return line.split("=")[1].strip().strip('"')
+    try:
+        for line in open("/usr/boot/plnode.txt", 'r').readlines():
+            if line.startswith("NET_DEVICE"):
+                return line.split("=")[1].strip().strip('"')
+    except:
+        pass
     return None
 
 def get_if_from_hwaddr(hwaddr):
+    import sioc
     devs = sioc.gifconf()
     for dev in devs:
         dev_hwaddr = sioc.gifhwaddr(dev)
@@ -54,7 +54,7 @@ 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
@@ -112,6 +112,36 @@ def write_temp_file(do_write, mode=None, uidgid=None):
     finally: f.close()
     return temporary_filename
 
+# replace a target file with a new contents - checks for changes
+# 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=""
+    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: 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)
+    os.rename(name,target)
+    if chmod: os.chmod(target,chmod)
+    return True
+
 # utilities functions to get (cached) information from the node
 
 # get node_id from /etc/planetlab/node_id and cache it