[PATCH v6 16/16] config: Make configuration directories configurable

[Milan Zamazal]

A newly introduced LIBCAMERA_CONFIG_DIR environment variable specifies a
directory or a list of directories separated by colons where to look for
the libcamera configuration file before trying the standard locations.

Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
---
 Documentation/runtime_configuration.rst     |  5 +++++
 src/libcamera/base/global_configuration.cpp | 17 +++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/Documentation/runtime_configuration.rst b/Documentation/runtime_configuration.rst
index 59211169..c73d02e3 100644
--- a/Documentation/runtime_configuration.rst
+++ b/Documentation/runtime_configuration.rst
@@ -19,6 +19,11 @@ order:
 - LIBCAMERA_SYSCONF_DIR/configuration.yaml
 - /etc/libcamera/configuration.yaml
 
+If LIBCAMERA_CONFIG_DIR environment variable is non-empty then it
+specifies additional directories where to look for the configuration
+file, before looking at the standard locations. It can be a single
+directory or multiple directories separated by colons.
+
 The default name of the configuration file, configuration.yaml, can be
 overridden in LIBCAMERA_CONFIG_NAME environment variable. The variable
 can specify just an alternative configuration file name to be looked up
diff --git a/src/libcamera/base/global_configuration.cpp b/src/libcamera/base/global_configuration.cpp
index f35b3dae..315ea7ad 100644
--- a/src/libcamera/base/global_configuration.cpp
+++ b/src/libcamera/base/global_configuration.cpp
@@ -59,12 +59,6 @@ bool loadFile(const std::filesystem::path &fileName)
 	return true;
 }
 
-const std::vector<std::filesystem::path>
-	globalConfigurationDirectories = {
-		std::filesystem::path(LIBCAMERA_SYSCONF_DIR),
-		std::filesystem::path("/etc/libcamera"),
-	};
-
 void load()
 {
 	const char *libcameraConfigName =
@@ -81,6 +75,17 @@ void load()
 	if (configName.empty())
 		configName = std::filesystem::path("configuration.yaml");
 
+	const char *const configDir = utils::secure_getenv("LIBCAMERA_CONFIG_DIR");
+	std::vector<std::filesystem::path> globalConfigurationDirectories;
+	if (configDir)
+		for (auto const &path : utils::split(configDir, ":"))
+			if (!path.empty())
+				globalConfigurationDirectories.push_back(path);
+	globalConfigurationDirectories.push_back(
+		std::filesystem::path(LIBCAMERA_SYSCONF_DIR));
+	globalConfigurationDirectories.push_back(
+		std::filesystem::path("/etc/libcamera"));
+
 	std::filesystem::path userConfigurationDirectory;
 	char *xdgConfigHome = utils::secure_getenv("XDG_CONFIG_HOME");
 	if (xdgConfigHome) {
-- 
2.44.2