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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* utils.cpp - Miscellaneous utility functions
*/
#include "libcamera/internal/utils.h"
#include <dlfcn.h>
#include <elf.h>
#include <iomanip>
#include <limits.h>
#include <link.h>
#include <sstream>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
/**
* \file utils.h
* \brief Miscellaneous utility functions
*/
/* musl doesn't declare _DYNAMIC in link.h, declare it manually. */
extern ElfW(Dyn) _DYNAMIC[];
namespace libcamera {
namespace utils {
/**
* \brief Strip the directory prefix from the path
* \param[in] path The path to process
*
* basename is implemented differently across different C libraries. This
* implementation matches the one provided by the GNU libc, and does not
* modify its input parameter.
*
* \return A pointer within the given path without any leading directory
* components.
*/
const char *basename(const char *path)
{
const char *base = strrchr(path, '/');
return base ? base + 1 : path;
}
/**
* \brief Get an environment variable
* \param[in] name The name of the variable to return
*
* The environment list is searched to find the variable 'name', and the
* corresponding string is returned.
*
* If 'secure execution' is required then this function always returns NULL to
* avoid vulnerabilities that could occur if set-user-ID or set-group-ID
* programs accidentally trust the environment.
*
* \return A pointer to the value in the environment or NULL if the requested
* environment variable doesn't exist or if secure execution is required.
*/
char *secure_getenv(const char *name)
{
#if HAVE_SECURE_GETENV
return ::secure_getenv(name);
#else
if (issetugid())
return NULL;
return getenv(name);
#endif
}
/**
* \brief Identify the dirname portion of a path
* \param[in] path The full path to parse
*
* This function conforms with the behaviour of the %dirname() function as
* defined by POSIX.
*
* \return A string of the directory component of the path
*/
std::string dirname(const std::string &path)
{
if (path.empty())
return ".";
/*
* Skip all trailing slashes. If the path is only made of slashes,
* return "/".
*/
size_t pos = path.size() - 1;
while (path[pos] == '/') {
if (!pos)
return "/";
pos--;
}
/*
* Find the previous slash. If the path contains no non-trailing slash,
* return ".".
*/
while (path[pos] != '/') {
if (!pos)
return ".";
pos--;
}
/*
* Return the directory name up to (but not including) any trailing
* slash. If this would result in an empty string, return "/".
*/
while (path[pos] == '/') {
if (!pos)
return "/";
pos--;
}
return path.substr(0, pos + 1);
}
/**
* \fn std::vector<typename T::key_type> map_keys(const T &map)
* \brief Retrieve the keys of a std::map<>
* \param[in] map The map whose keys to retrieve
* \return A std::vector<> containing the keys of \a map
*/
/**
* \fn libcamera::utils::set_overlap(InputIt1 first1, InputIt1 last1,
* InputIt2 first2, InputIt2 last2)
* \brief Count the number of elements in the intersection of two ranges
*
* Count the number of elements in the intersection of the sorted ranges [\a
* first1, \a last1) and [\a first1, \a last2). Elements are compared using
* operator< and the ranges must be sorted with respect to the same.
*
* \return The number of elements in the intersection of the two ranges
*/
/**
* \typedef clock
* \brief The libcamera clock (monotonic)
*/
/**
* \typedef duration
* \brief The libcamera duration related to libcamera::utils::clock
*/
/**
* \typedef time_point
* \brief The libcamera time point related to libcamera::utils::clock
*/
/**
* \brief Convert a duration to a timespec
* \param[in] value The duration
* \return A timespec expressing the duration
*/
struct timespec duration_to_timespec(const duration &value)
{
uint64_t nsecs = std::chrono::duration_cast<std::chrono::nanoseconds>(value).count();
struct timespec ts;
ts.tv_sec = nsecs / 1000000000ULL;
ts.tv_nsec = nsecs % 1000000000ULL;
return ts;
}
/**
* \brief Convert a time point to a string representation
* \param[in] time The time point
* \return A string representing the time point in hh:mm:ss.nanoseconds format
*/
std::string time_point_to_string(const time_point &time)
{
uint64_t nsecs = std::chrono::duration_cast<std::chrono::nanoseconds>(time.time_since_epoch()).count();
unsigned int secs = nsecs / 1000000000ULL;
std::ostringstream ossTimestamp;
ossTimestamp.fill('0');
ossTimestamp << secs / (60 * 60) << ":"
<< std::setw(2) << (secs / 60) % 60 << ":"
<< std::setw(2) << secs % 60 << "."
<< std::setw(9) << nsecs % 1000000000ULL;
return ossTimestamp.str();
}
std::basic_ostream<char, std::char_traits<char>> &
operator<<(std::basic_ostream<char, std::char_traits<char>> &stream, const _hex &h)
{
stream << "0x";
std::ostream::fmtflags flags = stream.setf(std::ios_base::hex,
std::ios_base::basefield);
std::streamsize width = stream.width(h.w);
char fill = stream.fill('0');
stream << h.v;
stream.flags(flags);
stream.width(width);
stream.fill(fill);
return stream;
}
/**
* \fn hex(T value, unsigned int width)
* \brief Write an hexadecimal value to an output string
* \param value The value
* \param width The width
*
* Return an object of unspecified type such that, if \a os is the name of an
* output stream of type std::ostream, and T is an integer type, then the
* expression
*
* \code{.cpp}
* os << utils::hex(value)
* \endcode
*
* will output the \a value to the stream in hexadecimal form with the base
* prefix and the filling character set to '0'. The field width is set to \a
* width if specified to a non-zero value, or to the native width of type T
* otherwise. The \a os stream configuration is not modified.
*/
/**
* \brief Copy a string with a size limit
* \param[in] dst The destination string
* \param[in] src The source string
* \param[in] size The size of the destination string
*
* This function copies the null-terminated string \a src to \a dst with a limit
* of \a size - 1 characters, and null-terminates the result if \a size is
* larger than 0. If \a src is larger than \a size - 1, \a dst is truncated.
*
* \return The size of \a src
*/
size_t strlcpy(char *dst, const char *src, size_t size)
{
if (size) {
strncpy(dst, src, size);
dst[size - 1] = '\0';
}
return strlen(src);
}
details::StringSplitter::StringSplitter(const std::string &str, const std::string &delim)
: str_(str), delim_(delim)
{
}
details::StringSplitter::iterator::iterator(const details::StringSplitter *ss, std::string::size_type pos)
: ss_(ss), pos_(pos)
{
next_ = ss_->str_.find(ss_->delim_, pos_);
}
details::StringSplitter::iterator &details::StringSplitter::iterator::operator++()
{
pos_ = next_;
if (pos_ != std::string::npos) {
pos_ += ss_->delim_.length();
next_ = ss_->str_.find(ss_->delim_, pos_);
}
return *this;
}
std::string details::StringSplitter::iterator::operator*() const
{
std::string::size_type count;
count = next_ != std::string::npos ? next_ - pos_ : next_;
return ss_->str_.substr(pos_, count);
}
bool details::StringSplitter::iterator::operator!=(const details::StringSplitter::iterator &other) const
{
return pos_ != other.pos_;
}
details::StringSplitter::iterator details::StringSplitter::begin() const
{
return iterator(this, 0);
}
details::StringSplitter::iterator details::StringSplitter::end() const
{
return iterator(this, std::string::npos);
}
/**
* \fn template<typename Container, typename UnaryOp> \
* std::string utils::join(const Container &items, const std::string &sep, UnaryOp op)
* \brief Join elements of a container in a string with a separator
* \param[in] items The container
* \param[in] sep The separator to add between elements
* \param[in] op A function that converts individual elements to strings
*
* This function joins all elements in the \a items container into a string and
* returns it. The \a sep separator is added between elements. If the container
* elements are not implicitly convertible to std::string, the \a op function
* shall be provided to perform conversion of elements to std::string.
*
* \return A string that concatenates all elements in the container
*/
/**
* \fn split(const std::string &str, const std::string &delim)
* \brief Split a string based on a delimiter
* \param[in] str The string to split
* \param[in] delim The delimiter string
*
* This function splits the string \a str into substrings based on the
* delimiter \a delim. It returns an object of unspecified type that can be
* used in a range-based for loop and yields the substrings in sequence.
*
* \return An object that can be used in a range-based for loop to iterate over
* the substrings
*/
details::StringSplitter split(const std::string &str, const std::string &delim)
{
/** \todo Try to avoid copies of str and delim */
return details::StringSplitter(str, delim);
}
/**
* \brief Remove any non-ASCII characters from a string
* \param[in] str The string to strip
*
* Remove all non-ASCII characters from a string.
*
* \return A string equal to \a str stripped out of all non-ASCII characters
*/
std::string toAscii(const std::string &str)
{
std::string ret;
for (const char &c : str)
if (!(c & 0x80))
ret += c;
return ret;
}
/**
* \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 Retrieve the path to the build directory
*
* During development, it is useful to run libcamera binaries directly from the
* build directory without installing them. This function helps components that
* need to locate resources in the build tree, such as IPA modules or IPA proxy
* workers, by providing them with the path to the root of the build directory.
* Callers can then use it to complement or override searches in system-wide
* directories.
*
* If libcamera has been installed, the build directory path is not available
* and this function returns an empty string.
*
* \return The path to the build directory if running from a build, or an empty
* string otherwise
*/
std::string libcameraBuildPath()
{
if (isLibcameraInstalled())
return std::string();
Dl_info info;
/* Look up our own symbol. */
int ret = dladdr(reinterpret_cast<void *>(libcameraBuildPath), &info);
if (ret == 0)
return std::string();
std::string path = dirname(info.dli_fname) + "/../../";
char *real = realpath(path.c_str(), nullptr);
if (!real)
return std::string();
path = real;
free(real);
return path + "/";
}
/**
* \brief Retrieve the path to the source directory
*
* During development, it is useful to run libcamera binaries directly from the
* build directory without installing them. This function helps components that
* need to locate resources in the source tree, such as IPA configuration
* files, by providing them with the path to the root of the source directory.
* Callers can then use it to complement or override searches in system-wide
* directories.
*
* If libcamera has been installed, the source directory path is not available
* and this function returns an empty string.
*
* \return The path to the source directory if running from a build directory,
* or an empty string otherwise
*/
std::string libcameraSourcePath()
{
std::string path = libcameraBuildPath();
if (path.empty())
return std::string();
path += "source";
char *real = realpath(path.c_str(), nullptr);
if (!real)
return std::string();
path = real;
free(real);
struct stat statbuf;
int ret = stat(path.c_str(), &statbuf);
if (ret < 0 || (statbuf.st_mode & S_IFMT) != S_IFDIR)
return std::string();
return path + "/";
}
/**
* \fn alignDown(unsigned int value, unsigned int alignment)
* \brief Align \a value down to \a alignment
* \param[in] value The value to align
* \param[in] alignment The alignment
* \return The value rounded down to the nearest multiple of \a alignment
*/
/**
* \fn alignUp(unsigned int value, unsigned int alignment)
* \brief Align \a value up to \a alignment
* \param[in] value The value to align
* \param[in] alignment The alignment
* \return The value rounded up to the nearest multiple of \a alignment
*/
/**
* \fn reverse(T &&iterable)
* \brief Wrap an iterable to reverse iteration in a range-based loop
* \param[in] iterable The iterable
* \return A value of unspecified type that, when used in a range-based for
* loop, will cause the loop to iterate over the \a iterable in reverse order
*/
} /* namespace utils */
} /* namespace libcamera */
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