Add error handling for post binary hook script

Raise an exception if there was an issue with handling any command
when signing the binaries for MUSCA targets.

Author: jainvikas8

tools/targets/ARM_MUSCA.py

@@ -74,7 +74,11 @@ def musca_tfm_bin(t_self, non_secure_bin, secure_bin, target_name):
         s_signed_bin,
     ]
 
-    run_cmd(cmd, MBED_OS_ROOT)
+    retcode = run_cmd(cmd, MBED_OS_ROOT)
+    if retcode:
+        raise Exception("Unable to sign " + target_name +
+                            " secure binary, Error code: " + retcode)
+        return
 
     #2. Run wrapper to sign the non-secure mbed binary
     cmd = [
@@ -103,7 +107,11 @@ def musca_tfm_bin(t_self, non_secure_bin, secure_bin, target_name):
         ns_signed_bin,
     ]
 
-    run_cmd(cmd, MBED_OS_ROOT)
+    retcode = run_cmd(cmd, MBED_OS_ROOT)
+    if retcode:
+        raise Exception("Unable to sign " + target_name +
+                            " non-secure binary, Error code: " + retcode)
+        return
 
     #3. Concatenate signed secure TFM and non-secure mbed binaries
     cmd = [
@@ -119,7 +127,11 @@ def musca_tfm_bin(t_self, non_secure_bin, secure_bin, target_name):
         concatenated_bin,
     ]
 
-    run_cmd(cmd, MBED_OS_ROOT)
+    retcode = run_cmd(cmd, MBED_OS_ROOT)
+    if retcode:
+        raise Exception("Unable to concatenate " + target_name +
+                            " binaries, Error code: " + retcode)
+        return
 
     #4. Concatenate mcuboot and signed binary and overwrite mbed built binary file
     mcuboot_image_size = find_bl2_size(flash_layout)
@@ -145,7 +157,11 @@ def run_cmd(cmd, directory):
 
     POPEN_INSTANCE = subprocess.Popen(
         cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
         cwd=directory,
     )
 
     POPEN_INSTANCE.communicate()
+    return POPEN_INSTANCE.returncode
+