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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2020, Google Inc.
*
* sysfs.cpp - Miscellaneous utility functions to access sysfs
*/
#include "libcamera/internal/sysfs.h"
#include <sstream>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include "libcamera/internal/log.h"
/**
* \file sysfs.h
* \brief Miscellaneous utility functions to access sysfs
*/
namespace libcamera {
LOG_DEFINE_CATEGORY(SysFs);
namespace sysfs {
/**
* \brief Retrieve the sysfs path for a character device
* \param[in] deviceNode Path to character device node
* \return The sysfs path on success or an empty string on failure
*/
std::string charDevPath(const std::string &deviceNode)
{
struct stat st;
int ret = stat(deviceNode.c_str(), &st);
if (ret < 0) {
ret = -errno;
LOG(SysFs, Error)
<< "Unable to stat '" << deviceNode << "': "
<< strerror(-ret);
return {};
}
std::ostringstream dev("/sys/dev/char/", std::ios_base::ate);
dev << major(st.st_rdev) << ":" << minor(st.st_rdev);
return dev.str();
}
} /* namespace sysfs */
} /* namespace libcamera */
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