cbdc93e9d1
Move the utils functionality to the libcamera/base library. Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
140 lines
3.5 KiB
C++
140 lines
3.5 KiB
C++
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2021, Google Inc.
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*
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* source_paths.cpp - Identify libcamera source and build paths
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*/
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#include "libcamera/internal/source_paths.h"
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#include <dlfcn.h>
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#include <elf.h>
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#include <link.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <libcamera/base/utils.h>
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/**
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* \file source_paths.h
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* \brief Identify the build and source path of a not-yet-installed library
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*/
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/* musl doesn't declare _DYNAMIC in link.h, declare it manually. */
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extern ElfW(Dyn) _DYNAMIC[];
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namespace libcamera {
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namespace {
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/**
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* \brief Check if libcamera is installed or not
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*
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* Utilise the build_rpath dynamic tag which is stripped out by meson at
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* install time to determine at runtime if the library currently executing
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* has been installed or not.
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*
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* \return True if libcamera is installed, false otherwise
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*/
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bool isLibcameraInstalled()
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{
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/*
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* DT_RUNPATH (DT_RPATH when the linker uses old dtags) is removed on
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* install.
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*/
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for (const ElfW(Dyn) *dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn) {
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if (dyn->d_tag == DT_RUNPATH || dyn->d_tag == DT_RPATH)
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return false;
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}
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return true;
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}
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} /* namespace */
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namespace utils {
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/**
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* \brief Retrieve the path to the build directory
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*
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* During development, it is useful to run libcamera binaries directly from the
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* build directory without installing them. This function helps components that
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* need to locate resources in the build tree, such as IPA modules or IPA proxy
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* workers, by providing them with the path to the root of the build directory.
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* Callers can then use it to complement or override searches in system-wide
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* directories.
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*
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* If libcamera has been installed, the build directory path is not available
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* and this function returns an empty string.
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*
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* \return The path to the build directory if running from a build, or an empty
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* string otherwise
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*/
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std::string libcameraBuildPath()
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{
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if (isLibcameraInstalled())
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return std::string();
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Dl_info info;
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/* Look up our own symbol. */
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int ret = dladdr(reinterpret_cast<void *>(libcameraBuildPath), &info);
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if (ret == 0)
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return std::string();
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std::string path = dirname(info.dli_fname) + "/../../";
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char *real = realpath(path.c_str(), nullptr);
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if (!real)
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return std::string();
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path = real;
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free(real);
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return path + "/";
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}
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/**
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* \brief Retrieve the path to the source directory
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*
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* During development, it is useful to run libcamera binaries directly from the
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* build directory without installing them. This function helps components that
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* need to locate resources in the source tree, such as IPA configuration
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* files, by providing them with the path to the root of the source directory.
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* Callers can then use it to complement or override searches in system-wide
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* directories.
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*
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* If libcamera has been installed, the source directory path is not available
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* and this function returns an empty string.
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*
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* \return The path to the source directory if running from a build directory,
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* or an empty string otherwise
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*/
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std::string libcameraSourcePath()
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{
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std::string path = libcameraBuildPath();
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if (path.empty())
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return std::string();
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path += "source";
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char *real = realpath(path.c_str(), nullptr);
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if (!real)
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return std::string();
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path = real;
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free(real);
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struct stat statbuf;
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int ret = stat(path.c_str(), &statbuf);
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if (ret < 0 || (statbuf.st_mode & S_IFMT) != S_IFDIR)
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return std::string();
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return path + "/";
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}
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} /* namespace utils */
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} /* namespace libcamera */
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