[libcamera-devel] [PATCH 05/11] libcamera: ipa_proxy: Provide suport for IPA configuration files

[Jacopo Mondi]

Hi, one more question

On Mon, Apr 27, 2020 at 06:17:07AM +0300, Laurent Pinchart wrote:
> IPA modules may require configuration files, which may be stored in
> different locations in the file system. To standardize file locations
> between all IPAs and pipeline handlers, provide a helper function to
> locate a configuration file by searching in the following directories:
>
> - All directories specified in the LIBCAMERA_IPA_CONFIG_PATH environment
>   variable ; or
> - In the build tree if libcamera is not installed ; otherwise
> - In standard system locations (etc and share directories).

How do we deal with permissions here ? I think it's up to
distributions handle this though

>
> More locations, or extensions to the mechanism, may be implemented
> later.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/ipa/meson.build                      |  6 ++
>  src/libcamera/include/ipa_proxy.h        | 11 ++-
>  src/libcamera/ipa_proxy.cpp              | 91 +++++++++++++++++++++++-
>  src/libcamera/proxy/ipa_proxy_linux.cpp  |  2 +-
>  src/libcamera/proxy/ipa_proxy_thread.cpp |  2 +-
>  5 files changed, 105 insertions(+), 7 deletions(-)
>
> diff --git a/src/ipa/meson.build b/src/ipa/meson.build
> index cb4e3ab3388f..145bf8105af7 100644
> --- a/src/ipa/meson.build
> +++ b/src/ipa/meson.build
> @@ -1,10 +1,16 @@
>  ipa_install_dir = join_paths(get_option('libdir'), 'libcamera')
> +ipa_data_dir = join_paths(get_option('datadir'), 'libcamera', 'ipa')
> +ipa_sysconf_dir = join_paths(get_option('sysconfdir'), 'libcamera', 'ipa')
>
>  ipa_includes = [
>      libcamera_includes,
>      libcamera_internal_includes,
>  ]
>
> +config_h.set('IPA_CONFIG_DIR',
> +             '"' + join_paths(get_option('prefix'), ipa_sysconf_dir) +
> +             ':' + join_paths(get_option('prefix'), ipa_data_dir) + '"')
> +
>  config_h.set('IPA_MODULE_DIR',
>               '"' + join_paths(get_option('prefix'), ipa_install_dir) + '"')
>
> diff --git a/src/libcamera/include/ipa_proxy.h b/src/libcamera/include/ipa_proxy.h
> index e696551af39f..1111065b36a7 100644
> --- a/src/libcamera/include/ipa_proxy.h
> +++ b/src/libcamera/include/ipa_proxy.h
> @@ -13,22 +13,27 @@
>
>  #include <ipa/ipa_interface.h>
>
> -#include "ipa_module.h"
> -
>  namespace libcamera {
>
> +class IPAModule;
> +
>  class IPAProxy : public IPAInterface
>  {
>  public:
> -	IPAProxy();
> +	IPAProxy(IPAModule *ipam);
>  	~IPAProxy();
>
>  	bool isValid() const { return valid_; }
>
> +	std::string configurationFile(const std::string &file) const;
> +
>  protected:
>  	std::string resolvePath(const std::string &file) const;
>
>  	bool valid_;
> +
> +private:
> +	IPAModule *ipam_;
>  };
>
>  class IPAProxyFactory
> diff --git a/src/libcamera/ipa_proxy.cpp b/src/libcamera/ipa_proxy.cpp
> index 43ac9afc25cb..ea69e63d6bb8 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)
>  {
>  }
>
> @@ -57,6 +61,89 @@ IPAProxy::~IPAProxy()
>   * \return True if the IPAProxy is valid, false otherwise
>   */
>
> +/**
> + * \brief Retrieve the absolute path to an IPA configuration file
> + * \param[in] name The configuration 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;
> +		}
> +	}
> +
> +	/*
> +	 * 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 root = utils::libcameraSourcePath();
> +	if (!root.empty()) {
> +		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;
> +
> +		return std::string();
> +	}
> +
> +	/* Else look in the system locations. */
> +	for (const auto &dir : utils::split(IPA_CONFIG_DIR, ":")) {
> +		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;
> +	}
> +
> +	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
> diff --git a/src/libcamera/proxy/ipa_proxy_linux.cpp b/src/libcamera/proxy/ipa_proxy_linux.cpp
> index 2aa80b946704..89f5cb54687b 100644
> --- a/src/libcamera/proxy/ipa_proxy_linux.cpp
> +++ b/src/libcamera/proxy/ipa_proxy_linux.cpp
> @@ -44,7 +44,7 @@ private:
>  };
>
>  IPAProxyLinux::IPAProxyLinux(IPAModule *ipam)
> -	: proc_(nullptr), socket_(nullptr)
> +	: IPAProxy(ipam), proc_(nullptr), socket_(nullptr)
>  {
>  	LOG(IPAProxy, Debug)
>  		<< "initializing dummy proxy: loading IPA from "
> diff --git a/src/libcamera/proxy/ipa_proxy_thread.cpp b/src/libcamera/proxy/ipa_proxy_thread.cpp
> index 368ccca1cf60..1ebb9b6a6c9d 100644
> --- a/src/libcamera/proxy/ipa_proxy_thread.cpp
> +++ b/src/libcamera/proxy/ipa_proxy_thread.cpp
> @@ -73,7 +73,7 @@ private:
>  };
>
>  IPAProxyThread::IPAProxyThread(IPAModule *ipam)
> -	: running_(false)
> +	: IPAProxy(ipam), running_(false)
>  {
>  	if (!ipam->load())
>  		return;
> --
> Regards,
>
> Laurent Pinchart
>
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