coreutils

// uname.c, version 1.0.1

// OMKOV coreutils implementation of POSIX uname

// Copyright (C) 2020, Jakob Wakeling

// MIT Licence

#include "util/optget.h"

#include <sys/utsname.h>

#include <unistd.h>

#include <stdbool.h>

#include <stdio.h>

#define VERSION "1.0.1"

static struct lop lops[] = {

	{ "help",    ARG_NUL, 256 },

	{ "version", ARG_NUL, 257 },

	{ NULL, 0, 0 }

};

static int mode;

static inline void print(char *string);

static void hlp(void);

static void ver(void);

int main(int ac, char *av[]) { (void)(ac);

	struct opt opt = OPTGET_INIT; opt.str = "amnrsv"; opt.lops = lops;

	for (int o; (o = optget(&opt, av, 1)) != -1;) switch (o) {

	case 'a': { mode |= 31; break; }

	case 'm': { mode |=  1; break; }

	case 'n': { mode |=  2; break; }

	case 'r': { mode |=  4; break; }

	case 's': { mode |=  8; break; }

	case 'v': { mode |= 16; break; }

	case 256: { hlp(); return 0; }

	case 257: { ver(); return 0; }

	default: { return 1; }

	}

	if (mode == 0) { mode |= 8; }

	struct utsname name; uname(&name);

	if (mode &  8) { print(name.sysname); }

	if (mode &  2) { print(name.nodename); }

	if (mode &  4) { print(name.release); }

	if (mode & 16) { print(name.version); }

	if (mode &  1) { print(name.machine); }

	fputc('\n', stdout);

	return 0;

}

static inline void print(char *string) {

	static bool spc = false;

	if (spc) { fputc(' ', stdout); } else { spc = true; }

	fputs(string, stdout); return;

}

static void hlp(void) {

	puts("uname - return system name\n");

	puts("usage: uname [-amnrsv]\n");

	puts("options:");

	puts("  -a         Print all system characteristics");

	puts("  -m         Print the system hardware type");

	puts("  -n         Print the system network node name");

	puts("  -r         Print the current release level of the OS");

	puts("  -s         Print the name of the OS");

	puts("  -v         Print the current version of the OS");

	puts("  --help     Display help information");

	puts("  --version  Display version information");

}

static void ver(void) {

	puts("OMKOV coreutils uname, version " VERSION);

	puts("Copyright (C) 2020, Jakob Wakeling");

	puts("MIT Licence (https://opensource.org/licenses/MIT)");

}