Changeset 2160 for trunk

Timestamp:

Mar 26, 2012, 2:38:54 PM (13 years ago)

Author:

ezyang

Message:

Avoid races if /proc directory goes away

File:

• trunk/server/common/oursrc/fuse-better-mousetrapfs/better-mousetrapfs (modified) (1 diff)

trunk/server/common/oursrc/fuse-better-mousetrapfs/better-mousetrapfs

@@ -64 +64 @@
         except KeyError:
             group = '%d' % gid
-        cmdline = open('/proc/%d/cmdline' % pid).read().split('\0')[:-1]
-        exe = os.readlink('/proc/%d/exe' % pid)
-        status = dict(tuple(v.strip() for v in l.split(':', 1))
-                      for l in open('/proc/%d/status' % pid).readlines())
-        cwd = os.readlink('/proc/%d/cwd' % pid)
+
+        # avoid races if process goes away (not 100% sure if this is
+        # possible; may be possible for multithreaded/async IO)
+        olddir = os.getcwd()
+        os.chdir("/proc/%d" % pid)
+
+        try:
+            cmdline = open('cmdline').read().split('\0')[:-1]
+            exe = os.readlink('exe')
+            status = dict(tuple(v.strip() for v in l.split(':', 1))
+                          for l in open('status').readlines())
+            cwd = os.readlink('cwd')
+        finally:
+            os.chdir(olddir)
 
         syslog.syslog(