(POSIX / pid_exists()) - as a follow up of http://stackoverflow.com/questions/568271/how-to-check-if-there-exists-a-process-with-a-given-pid/6940314#comment11929962_6940314 be more explicit in handing os.kill() error codes and raise exception if errcode not in (ESRCH, EPERM)

1 files changed, 13 insertions, 2 deletions

diff --git a/psutil/_psposix.py b/psutil/_psposix.py
index 8f36fedd..dcb93bdf 100644
--- a/psutil/_psposix.py
+++ b/psutil/_psposix.py
@@ -24,8 +24,19 @@ def pid_exists(pid):
     try:
         os.kill(pid, 0)
     except OSError:
-        e = sys.exc_info()[1]
-        return e.errno == errno.EPERM
+        err = sys.exc_info()[1]
+        if err.errno == errno.ESRCH:
+            # ESRCH == No such process
+            return False
+        elif err.errno == errno.EPERM:
+            # EPERM clearly means there's a process to deny access to
+            return True
+        else:
+            # According to "man 2 kill" possible error values are
+            # (EINVAL, EPERM, ESRCH) therefore we should bever get
+            # here. If we do let's be explicit in considering this
+            # an error.
+            raise err
     else:
         return True