1 files changed, 90 insertions, 2 deletions

diff --git a/src/libcamera/ipa_proxy.cpp b/src/libcamera/ipa_proxy.cpp
index 43ac9afc..401ac52d 100644
--- a/src/libcamera/ipa_proxy.cpp
+++ b/src/libcamera/ipa_proxy.cpp
@@ -8,8 +8,11 @@
 #include "ipa_proxy.h"
 
 #include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <unistd.h>
 
+#include "ipa_module.h"
 #include "log.h"
 #include "utils.h"
 
@@ -34,12 +37,13 @@ LOG_DEFINE_CATEGORY(IPAProxy)
 
 /**
  * \brief Construct an IPAProxy instance
+ * \param[in] ipam The IPA module
  *
  * IPAProxy instances shall be constructed through the IPAProxyFactory::create()
  * method implemented by the respective factories.
  */
-IPAProxy::IPAProxy()
-	: valid_(false)
+IPAProxy::IPAProxy(IPAModule *ipam)
+	: valid_(false), ipam_(ipam)
 {
 }
 
@@ -58,6 +62,90 @@ IPAProxy::~IPAProxy()
  */
 
 /**
+ * \brief Retrieve the absolute path to an IPA configuration file
+ * \param[in] name The configuration file name
+ *
+ * This function locates the configuration file for an IPA and returns its
+ * absolute path. It searches the following directories, in order:
+ *
+ * - All directories specified in the colon-separated LIBCAMERA_IPA_CONFIG_PATH
+ *   environment variable ; or
+ * - If libcamera is not installed, the src/ipa/ directory within the source
+ *   tree ; otherwise
+ * - The system sysconf (etc/libcamera/ipa) and the data (share/libcamera/ipa/)
+ *   directories.
+ *
+ * The system directories are not searched if libcamera is not installed.
+ *
+ * Within each of those directories, the function looks for a subdirectory
+ * named after the IPA module name, as reported in IPAModuleInfo::name, and for
+ * a file named \a name within that directory. The \a name is IPA-specific.
+ *
+ * \return The full path to the IPA configuration file, or an empty string if
+ * no configuration file can be found
+ */
+std::string IPAProxy::configurationFile(const std::string &name) const
+{
+	struct stat statbuf;
+	int ret;
+
+	/*
+	 * The IPA module name can be used as-is to build directory names as it
+	 * has been validated when loading the module.
+	 */
+	std::string ipaName = ipam_->info().name;
+
+	/* Check the environment variable first. */
+	const char *confPaths = utils::secure_getenv("LIBCAMERA_IPA_CONFIG_PATH");
+	if (confPaths) {
+		for (const auto &dir : utils::split(confPaths, ":")) {
+			if (dir.empty())
+				continue;
+
+			std::string confPath = dir + "/" + ipaName + "/" + name;
+			ret = stat(confPath.c_str(), &statbuf);
+			if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
+				return confPath;
+		}
+	}
+
+	std::string root = utils::libcameraSourcePath();
+	if (!root.empty()) {
+		/*
+		 * When libcamera is used before it is installed, load
+		 * configuration files from the source directory. The
+		 * configuration files are then located in the 'data'
+		 * subdirectory of the corresponding IPA module.
+		 */
+		std::string ipaConfDir = root + "src/ipa/" + ipaName + "/data";
+
+		LOG(IPAProxy, Info)
+			<< "libcamera is not installed. Loading IPA configuration from '"
+			<< ipaConfDir << "'";
+
+		std::string confPath = ipaConfDir + "/" + name;
+		ret = stat(confPath.c_str(), &statbuf);
+		if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
+			return confPath;
+
+	} else {
+		/* Else look in the system locations. */
+		for (const auto &dir : utils::split(IPA_CONFIG_DIR, ":")) {
+			std::string confPath = dir + "/" + ipaName + "/" + name;
+			ret = stat(confPath.c_str(), &statbuf);
+			if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
+				return confPath;
+		}
+	}
+
+	LOG(IPAProxy, Error)
+		<< "Configuration file '" << name
+		<< "' not found for IPA module '" << ipaName << "'";
+
+	return std::string();
+}
+
+/**
  * \brief Find a valid full path for a proxy worker for a given executable name
  * \param[in] file File name of proxy worker executable
  *