[libvirt PATCH 1/2] build: convert the run script to use Python

[Martin Kletzander]

On Thu, Mar 18, 2021 at 06:29:17PM +0000, Daniel P. Berrangé wrote:
>This fits with the goal of eliminating non-Python scripting languages,
>and makes forthcoming changes far easier.
>
>Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
>---
> run.in | 45 ++++++++++++++++++++++++++-------------------
> 1 file changed, 26 insertions(+), 19 deletions(-)
>
>diff --git a/run.in b/run.in
>index 6ddf5fc58f..99c67c586a 100644
>--- a/run.in
>+++ b/run.in
>@@ -1,6 +1,6 @@
>-#!/bin/sh
>+#!/usr/bin/env python3
> # libvirt 'run' programs locally script
>-# Copyright (C) 2012-2013 Red Hat, Inc.
>+# Copyright (C) 2012-2021 Red Hat, Inc.
> #
> # This library is free software; you can redistribute it and/or
> # modify it under the terms of the GNU Lesser General Public
>@@ -40,35 +40,42 @@
> #
> #----------------------------------------------------------------------
>
>+import os
>+import os.path
>+import random
>+import sys
>+
> # Function to intelligently prepend a path to an environment variable.
> # See https://stackoverflow.com/a/9631350
>-prepend()
>-{
>-    eval $1="$2\${$1:+:\$$1}"
>-}
>+def prepend(env, varname, extradir):
>+    if varname in os.environ:
>+        env[varname] = extradir + ":" + env[varname]
>+    else:
>+        env[varname] = extradir
>+
>+here = "@abs_builddir@"
>
>-# Find this script.
>-b=@abs_builddir@
>+if len(sys.argv) < 2:
>+    print("syntax: %s BINARY [ARGS...]" % sys.argv[0], file=sys.stderr)
>+    sys.exit(1)
>
>-prepend LD_LIBRARY_PATH "$b/src"
>-export LD_LIBRARY_PATH
>+prog = sys.argv[1]
>+args = sys.argv[1:]
>+env = os.environ
>
>-prepend PKG_CONFIG_PATH "$b/src"
>-export PKG_CONFIG_PATH
>
>-prepend PATH "$b/tools"
>-export PATH
>+prepend(env, "LD_LIBRARY_PATH", os.path.join(here, "src"))
>+prepend(env, "PKG_CONFIG_PATH", os.path.join(here, "src"))
>+prepend(env, "PATH", os.path.join(here, "tools"))
>
> # Ensure that any 3rd party apps using libvirt.so from the build tree get
> # files resolved to the build/source tree too. Typically useful for language
> # bindings running tests against non-installed libvirt.
>-LIBVIRT_DIR_OVERRIDE=1
>-export LIBVIRT_DIR_OVERRIDE
>+env["LIBVIRT_DIR_OVERRIDE"] = "1"
>
> # This is a cheap way to find some use-after-free and uninitialized
> # read problems when using glibc.
>-random_val="$(awk 'BEGIN{srand(); print 1+int(255*rand())}' < /dev/null)"
>-export MALLOC_PERTURB_=$random_val
>+env["MALLOC_PERTURB_"] = "%d" % random.randint(1, 255)
>
> # Run the program.
>-exec "$@"
>+os.execve(prog, args, env)

This is not functionally equivalent as the shell script modified also its own
PATH variable and then the exec could search that.  If I am reading the docs
correctly, then os.execvpe() can do both of that, so I think you meant to use
that here.

If yes, than with that change:

Reviewed-by: Martin Kletzander <mkletzan at redhat.com>

>--
>2.30.2
>
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