[nrf fromlist] net: l2: wifi: Make build time certs as optional

Certificates usage depends on STA/AP mode, but we don't have that
information at a build time, so, make all certs as optional and if a
file isn't found then generate an empty header so that corresponding C
code will be built.

Any missing mandatory certificates will be validated before connection
and connection is failed.

Upstream PR #: 87656

Signed-off-by: Chaitanya Tata <[email protected]>

Author: krish2718

subsys/net/l2/wifi/CMakeLists.txt

@@ -33,53 +33,28 @@ if(CONFIG_WIFI_NM_WPA_SUPPLICANT_CRYPTO_ENTERPRISE AND CONFIG_NET_L2_WIFI_SHELL)
   # convert .pem files to array data at build time
   zephyr_include_directories(${gen_inc_dir})
 
-  generate_inc_file_for_target(
-      app
+  foreach(cert_file IN ITEMS
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/client.pem
-      ${gen_dir}/client.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/client-key.pem
-      ${gen_dir}/client-key.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/ca.pem
-      ${gen_dir}/ca.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/client2.pem
-      ${gen_dir}/client2.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/client-key2.pem
-      ${gen_dir}/client-key2.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/ca2.pem
-      ${gen_dir}/ca2.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/server.pem
-      ${gen_dir}/server.pem.inc
-      )
-
-  generate_inc_file_for_target(
-      app
       ${ZEPHYR_BASE}/samples/net/wifi/test_certs/server-key.pem
-      ${gen_dir}/server-key.pem.inc
       )
+    if(EXISTS ${cert_file})
+      get_filename_component(cert_name ${cert_file} NAME)
+      generate_inc_file_for_target(
+          app
+          ${cert_file}
+          ${gen_dir}/${cert_name}.inc
+          )
+    else()
+      get_filename_component(cert_name ${cert_file} NAME)
+      file(WRITE ${gen_dir}/${cert_name}.inc "// Empty file generated because ${cert_file} does not exist\n")
+    endif()
+  endforeach()
 
   # Add explicit dependency on app target for ZEPHYR_CURRENT_LIBRARY, so these
   # headers are generated at the correct point in the build