// Executable Name
//
// Douglas Thrift
//
// $Id$

#include <iostream>
#include <string>
#include <sstream>
#include <cstdio>

extern "C"
{
#include <sys/param.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
}

#include <cstdlib>

int main(int argc, char* argv[])
{
	std::string program(argv[0]);

	if (program.find('/') == std::string::npos)
	{
		std::istringstream path(::getenv("PATH") != NULL ? ::getenv("PATH")
			: std::string());

		do
		{
			std::string candidate;

			std::getline(path, candidate, ':');

			candidate += '/' + program;

			if (::access(candidate.c_str(), X_OK) == 0)
			{
				struct ::stat file;

				if (::stat(candidate.c_str(), &file) == 0
					&& S_ISREG(file.st_mode) && (::getuid() != 0
					|| (file.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0))
				{
					::lstat(candidate.c_str(), &file);

					if (S_ISLNK(file.st_mode))
					{
						char buffer[1024];
						int length(::readlink(candidate.c_str(), buffer, 1024));

						if (length == -1)
						{
							::perror(argv[0]);

							return 1;
						}

						program.assign(buffer, length);
					}
					else program = candidate;

					break;
				}
			}
		}
		while (path.good());
	}

	char executable[PATH_MAX];

	if (::realpath(program.c_str(), executable) == NULL)
	{
		::perror(argv[0]);

		return 1;
	}

	std::cout << "executable = " << executable << '\n';

	return 0;
}