[libcamera-devel] [PATCH LIBCAMERA v4 3/5] libcamera: utils: Move libcamera build path lookup to utis

[Kaaira Gupta]

The IPA proxy manager will need to find the libcamera build path exactly
the same way as the IPA module mnager. Move the isLibcameraInstalled()
and libcameraPath() functions to utils to make them reusable.

Signed-off-by: Kaaira Gupta <kgupta at es.iitr.ac.in>
---
 src/libcamera/include/utils.h |  4 +++
 src/libcamera/ipa_manager.cpp | 36 ++-----------------------
 src/libcamera/utils.cpp       | 49 +++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 34 deletions(-)

diff --git a/src/libcamera/include/utils.h b/src/libcamera/include/utils.h
index 9405977..bc96e79 100644
--- a/src/libcamera/include/utils.h
+++ b/src/libcamera/include/utils.h
@@ -143,6 +143,10 @@ private:
 
 details::StringSplitter split(const std::string &str, const std::string &delim);
 
+bool isLibcameraInstalled();
+
+std::string libcameraPath();
+
 } /* namespace utils */
 
 } /* namespace libcamera */
diff --git a/src/libcamera/ipa_manager.cpp b/src/libcamera/ipa_manager.cpp
index 238433d..0bd280c 100644
--- a/src/libcamera/ipa_manager.cpp
+++ b/src/libcamera/ipa_manager.cpp
@@ -9,9 +9,6 @@
 
 #include <algorithm>
 #include <dirent.h>
-#include <dlfcn.h>
-#include <elf.h>
-#include <link.h>
 #include <string.h>
 #include <sys/types.h>
 
@@ -27,35 +24,6 @@
  * \brief Image Processing Algorithm module manager
  */
 
-static bool isLibcameraInstalled()
-{
-	/* musl doesn't declare _DYNAMIC in link.h, declare it manually. */
-	extern ElfW(Dyn) _DYNAMIC[];
-
-	/*
-	 * DT_RUNPATH (DT_RPATH when the linker uses old dtags) is removed on
-	 * install.
-	 */
-	for (const ElfW(Dyn) *dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn) {
-		if (dyn->d_tag == DT_RUNPATH || dyn->d_tag == DT_RPATH)
-			return false;
-	}
-
-	return true;
-}
-
-static std::string libcameraPath()
-{
-	Dl_info info;
-
-	/* Look up our own symbol. */
-	int ret = dladdr(reinterpret_cast<void *>(libcameraPath), &info);
-	if (ret == 0)
-		return nullptr;
-
-	return info.dli_fname;
-}
-
 namespace libcamera {
 
 LOG_DEFINE_CATEGORY(IPAManager)
@@ -151,8 +119,8 @@ IPAManager::IPAManager()
 	 * path for the IPA from that point. We need to recurse one level of
 	 * sub-directories to match the build tree.
 	 */
-	if (!isLibcameraInstalled()) {
-		std::string ipaBuildPath = utils::dirname(libcameraPath()) + "/../ipa";
+	if (!utils::isLibcameraInstalled()) {
+		std::string ipaBuildPath = utils::dirname(utils::libcameraPath()) + "/../ipa";
 		constexpr int maxDepth = 1;
 
 		LOG(IPAManager, Info)
diff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp
index f566e88..7e118fa 100644
--- a/src/libcamera/utils.cpp
+++ b/src/libcamera/utils.cpp
@@ -7,7 +7,10 @@
 
 #include "utils.h"
 
+#include <dlfcn.h>
+#include <elf.h>
 #include <iomanip>
+#include <link.h>
 #include <sstream>
 #include <stdlib.h>
 #include <string.h>
@@ -18,6 +21,9 @@
  * \brief Miscellaneous utility functions
  */
 
+/* musl doesn't declare _DYNAMIC in link.h, declare it manually. */
+extern ElfW(Dyn) _DYNAMIC[];
+
 namespace libcamera {
 
 namespace utils {
@@ -310,6 +316,49 @@ details::StringSplitter split(const std::string &str, const std::string &delim)
 	return details::StringSplitter(str, delim);
 }
 
+/**
+ * \brief Check if libcamera is installed or not
+ *
+ * Utilise the build_rpath dynamic tag which is stripped out by meson at
+ * install time to determine at runtime if the library currently executing
+ * has been installed or not.
+ *
+ * \return True if libcamera is installed, false otherwise
+ */
+bool isLibcameraInstalled()
+{
+	/*
+	 * DT_RUNPATH (DT_RPATH when the linker uses old dtags) is removed on
+	 * install.
+	 */
+	for (const ElfW(Dyn) *dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn) {
+		if (dyn->d_tag == DT_RUNPATH || dyn->d_tag == DT_RPATH)
+			return false;
+	}
+
+	return true;
+}
+
+/**
+ * \brief Identify the libcamera.so path
+ *
+ * This function locates the running libcamera.so and returns its full path,
+ * including the file name.
+ *
+ * \return A string stating the path
+ */
+std::string libcameraPath()
+{
+	Dl_info info;
+
+	/* Look up our own symbol. */
+	int ret = dladdr(reinterpret_cast<void *>(libcameraPath), &info);
+	if (ret == 0)
+		return nullptr;
+
+	return info.dli_fname;
+}
+
 } /* namespace utils */
 
 } /* namespace libcamera */
-- 
2.17.1