Utility function to execute external functions.

- Legacy-Id: 2606

ietf/utils/pipe.py

@@ -0,0 +1,30 @@
+# Simplified interface to os.popen3()
+
+def pipe(cmd, str=None):
+    from popen2 import Popen3 as Popen
+    bufsize = 4096
+    MAX = 65536*16
+
+    if str and len(str) > 4096:                 # XXX: Hardcoded Linux 2.4, 2.6 pipe buffer size
+        bufsize = len(str)
+
+    pipe = Popen(cmd, True, bufsize)
+    if str:
+        pipe.tochild.write(str)
+        pipe.tochild.close()
+
+    out = ""
+    err = ""
+    while True:
+        str = pipe.fromchild.read()
+        if str:
+            out += str
+        code = pipe.poll()
+        if code > -1:
+            err = pipe.childerr.read()
+            break
+        if len(out) >= MAX:
+            err = "Output exceeds %s bytes and has been truncated"
+            break
+
+    return (code, out, err)