/* Summary: Gets Linux runtime information from VSF virtual file system.
*
*/
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <iomanip> // std::seprecision, std::fixed
// See: https://man7.org/linux/man-pages/man2/sysinfo.2.html
#include <sys/sysinfo.h>
void get_memory_info();
void show_sysinfo1();
void show_uptime();
void show_mount_points();
void show_kernel_runtime_config();
std::string readFile(std::string const& file);
int main(int argc, char** argv)
{
if(argc < 2){
std::cerr << " [ERROR] Usage: $ " << argv[0] << " <COMMAND> " << '\n';
return EXIT_FAILURE;
}
auto command = std::string{ argv[1] };
if(command == "version"){
std::cout << "===== Kernel Version ====================================" << '\n';
auto version = readFile("/proc/version");
std::cout << " System version = " << version << '\n';
return EXIT_SUCCESS;
}
if(command == "memory")
{
std::cout << " ==== Memory (Reported by command $ free -m ) ========" << '\n';
get_memory_info();
return EXIT_SUCCESS;
}
// Using the header: <sys/sysinfo.h>
// Note: this information is reported by the command $ free -m
if(command == "sysinfo1")
{
std::cout << " ===== System Info 1 (Reported by $ free -m and $ uptime ) === " << '\n';
show_sysinfo1();
return EXIT_SUCCESS;
}
if(command == "uptime")
{
std::cout << "===== System uptime since boot (Reported by $ uptime) ====" << '\n';
show_uptime();
return EXIT_SUCCESS;
}
if(command == "load-avg")
{
std::cout << " ==== System Load Average ================================" << '\n';
auto loadavg = readFile("/proc/loadavg");
std::cout << "Load average = " << loadavg << '\n';
return EXIT_SUCCESS;
}
if(command == "mount")
{
std::cout << " ====== System mount points ( Reported by command $ mount ) ===== " << '\n';
show_mount_points();
return EXIT_SUCCESS;
}
if(command == "sysctl")
{
std::cout << " ===== Kernel Runtime Information (Reported by $ sysctl ) ======= " << '\n';
show_kernel_runtime_config();
return EXIT_SUCCESS;
}
if(command == "dmesg")
{
std::cout << " ===== Kernel debug message (Reported by $ dmesg ) ==========" << '\n';
auto ifs = std::ifstream("/dev/kmsg");
std::string line;
while( std::getline(ifs, line) ){
std::cout << line << '\n';
}
}
if(command == "cpuinfo")
{
std::cout << "======= CPU Information =====================================" << '\n';
auto ifs = std::ifstream("/proc/cpuinfo");
std::string line;
while( std::getline(ifs, line) ){
std::cout << line << '\n';
}
}
return EXIT_SUCCESS;
}
void get_memory_info()
{
constexpr const char* meminfo_file = "/proc/meminfo";
// factor = 1 Gigabytes = 1024 * 1024 kbytes
constexpr double factor = 1024 * 1024;
auto ifs = std::ifstream{meminfo_file};
if(!ifs.good()){
throw std::runtime_error("Error: unable to memory-info file.");
}
std::string line, label;
std::uint64_t value;
while( std::getline(ifs, line) )
{
std::stringstream ss{line};
ss >> label >> value;
if(label == "MemTotal:")
std::cout << " Total memory (Gb) = " << (value / factor) << '\n';
if(label == "MemAvailable:")
std::cout << " Memory Available (Gb) = " << (value / factor) << '\n';
}
}
void show_sysinfo1()
{
struct sysinfo info;
::sysinfo(&info);
// 1 Gigabyte = 1024 megabytes = 1024 * 1024 kbytes = 1024 * 1024 * 1024 bytes;
constexpr double factor = 1024 * 1024 * 1024;
constexpr std::uint64_t one_day_to_seconds = 24 * 60 * 60;
std::cout << " [*] System uptime since boot (seconds) = " << info.uptime << '\n'
<< " [*] System uptime since boot (days) = " << info.uptime / one_day_to_seconds << '\n'
<< " [*] Total RAM memory (Gb) = " << info.totalram / factor << '\n'
<< " [*] Free RAM memory (Gb) = " << info.freeram / factor << '\n'
<< " [*] Total SWAP (Gb) = " << info.totalswap / factor << '\n'
<< " [*] Free SWAP (Gb) = " << info.freeswap / factor << '\n'
<< " [*] Number of processes running = " << info.procs << '\n'
<< '\n';
}
// Reported by command $ uptime
void show_uptime()
{
auto ifs = std::ifstream("/proc/uptime");
if( !ifs.good() ){ throw std::runtime_error("Error: unable to open uptime file "); }
double seconds;
ifs >> seconds;
uint64_t factor = 24 * 60 * 60;
std::cout << " Uptime in hours = " << seconds / ( 60 * 60) << '\n';
std::cout << " Uptime in days = " << seconds / factor << '\n';
}
void show_kernel_runtime_config()
{
auto show_field= [](std::string const& label, std::string const& file)
{
std::cout << " [*] "
<< std::setw(40) << std::right << (label + " => ")
<< std::setw(50) << std::left << readFile(file)
<< '\n';
};
std::cout << '\n';
show_field("Machine Hostname", "/proc/sys/kernel/hostname");
show_field("Kernel Version", "/proc/sys/kernel/osrelease");
show_field("Os type", "/proc/sys/kernel/ostype");
show_field("Boot unique ID identifier", "/proc/sys/kernel/random/boot_id");
show_field("Date which kernel was compiled", "/proc/sys/kernel/version");
show_field("Sysrq enabled (Emergency keys)", "/proc/sys/kernel/sysrq");
show_field("Max number of Cgroups namespaces", "/proc/sys/user/max_cgroup_namespaces");
show_field("Max number of Mount namespaces", "/proc/sys/user/max_net_namespaces");
}
void show_network_interfaces()
{
throw std::runtime_error("Error: not implemented yet.");
}
// Show mounted file systems, but ignore 'cgroup', 'overlay', 'fusectl'
void show_mount_points()
{
auto ifs = std::ifstream("/proc/mounts");
if(!ifs){
throw std::runtime_error("Error: unable to open file /proc/mounts");
}
std::cout << '\n';
std::cout << " "
<< std::setw(20) << std::left << "File system"
<< std::setw(20) << std::left << "Type"
<< std::setw(10) << std::left << "Mount point"
<< '\n';
std::cout << " "
<< std::setw(20) << std::left << "------------"
<< std::setw(20) << std::left << "----"
<< std::setw(10) << std::left << "-----------"
<< '\n';
std::string line, fsystem, type, mount_directory;
while( std::getline(ifs, line) )
{
auto ss = std::stringstream(line);
ss >> fsystem >> mount_directory >> type;
if( type != "cgroup" && type != "overlay" && type != "cgroup2")
{
std::cout << " "
<< std::setw(20) << std::left << fsystem
<< std::setw(20) << std::left << type
<< std::setw(10) << std::left << mount_directory
<< '\n';
}
}
}
// Requires: <string>, <stream>, <sstream>
std::string readFile(std::string const& file)
{
std::ifstream is(file);
if( !is.good() ){
throw std::runtime_error("Error: stream has errors.");
}
std::stringstream ss;
ss << is.rdbuf();
std::string m;
// Remove ending line character '\n' or '\r\n'.
std::getline(ss, m);
return m;
}