[PATCH] libcamera: ipa_manager: Allow disabling IPA module isolation

[Celine Laurencin]

For testing purposes with non-signed IPA, it can be useful to run IPA in non-isolated mode
to share the libcamera privilege.

Add a way to disable IPA module isolation through a new LIBCAMERA_IPA_DISABLE_ISOLATION
environment variable.
If isolation is disabled with LIBCAMERA_IPA_DISABLE_ISOLATION, all IPA modules run in
non-isolated mode and the environment variable LIBCAMERA_IPA_FORCE_ISOLATION is not
considered.

Signed-off-by: Celine Laurencin <celine.laurencin at nxp.com>
---
 Documentation/environment_variables.rst | 7 +++++++
 src/libcamera/ipa_manager.cpp           | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/Documentation/environment_variables.rst b/Documentation/environment_variables.rst
index 4e9fbb27..013acaf8 100644
--- a/Documentation/environment_variables.rst
+++ b/Documentation/environment_variables.rst
@@ -32,6 +32,13 @@ LIBCAMERA_IPA_FORCE_ISOLATION
 
    Example value: ``1``
 
+LIBCAMERA_IPA_DISABLE_ISOLATION
+   When set to a non-empty string, disable process isolation of all IPA modules.
+   If isolation is disabled, all IPA modules run in non-isolated mode and
+   the environment variable LIBCAMERA_IPA_FORCE_ISOLATION is not taking effect.
+
+   Example value: ``1``
+
 LIBCAMERA_IPA_MODULE_PATH
    Define custom search locations for IPA modules (`more <IPA module_>`__).
 
diff --git a/src/libcamera/ipa_manager.cpp b/src/libcamera/ipa_manager.cpp
index f4e0b633..f606c74c 100644
--- a/src/libcamera/ipa_manager.cpp
+++ b/src/libcamera/ipa_manager.cpp
@@ -295,6 +295,14 @@ IPAModule *IPAManager::module(PipelineHandler *pipe, uint32_t minVersion,
 bool IPAManager::isSignatureValid([[maybe_unused]] IPAModule *ipa) const
 {
 #if HAVE_IPA_PUBKEY
+	char *disableIsolation = utils::secure_getenv("LIBCAMERA_IPA_DISABLE_ISOLATION");
+	if (disableIsolation && disableIsolation[0] != '\0') {
+		LOG(IPAManager, Debug)
+			<< "Isolation of IPA module " << ipa->path()
+			<< " disabled through environment variable";
+		return true;
+	}
+
 	char *force = utils::secure_getenv("LIBCAMERA_IPA_FORCE_ISOLATION");
 	if (force && force[0] != '\0') {
 		LOG(IPAManager, Debug)
-- 
2.25.1