Use pure python code in place of os.system

os.system calls the user's shell, and is not directly checking for errors.
This should raise an error when cpio or rpm2cpio fail, or if they can't
be found.

Signed-off-by: Gaëtan Lehmann <gaetan.lehmann@vates.tech>

Author: glehmann

scripts/import_srpm.py

@@ -2,12 +2,45 @@
 import argparse
 import logging
 import os
+import shutil
 import subprocess
+from glob import glob
+
 
 def call_process(args):
     logging.debug("$ %s", args)
     subprocess.check_call(args)
 
+def pipe_commands(*commands: list[str]) -> bytes:
+    if not commands:
+        raise ValueError("The 'commands' list cannot be empty.")
+    if any(not cmd for cmd in commands):
+        raise ValueError("All commands in the list must be non-empty.")
+
+    processes: list[subprocess.Popen[bytes]] = []
+    last_process_stdout = None
+
+    for i, cmd_args in enumerate(commands):
+        process = subprocess.Popen(
+            cmd_args,
+            stdin=last_process_stdout,
+            stdout=subprocess.PIPE,
+        )
+        processes.append(process)
+        # to prevent deadlocks if the current process finishes before the previous one.
+        if last_process_stdout:
+            last_process_stdout.close()
+        last_process_stdout = process.stdout
+
+    final_stdout, _final_stderr = processes[-1].communicate()
+
+    for i, p in enumerate(processes):
+        p.wait()
+        if p.returncode != 0:
+            raise subprocess.CalledProcessError(returncode=p.returncode, cmd=commands[i])
+
+    return final_stdout
+
 def main():
     parser = argparse.ArgumentParser(description='Imports the contents of a source RPM into a git repository')
     parser.add_argument('source_rpm', help='local path to source RPM')
@@ -76,9 +109,10 @@ def main():
     print(" extracting SRPM...")
 
     os.chdir('SOURCES')
-    os.system('rpm2cpio "%s" | cpio -idmv' % source_rpm_abs)
+    pipe_commands(['rpm2cpio', source_rpm_abs], ['cpio', '-idmv'])
     os.chdir('..')
-    os.system('mv SOURCES/*.spec SPECS/')
+    for f in glob('SOURCES/*.spec'):
+        shutil.move(f, 'SPECS')
 
     print(" removing trademarked or copyrighted files...")