coreutils

// tee.c, version 1.0.3

// OMKOV coreutils implementation of POSIX tee

// Copyright (C) 2020, Jakob Wakeling

// MIT Licence

#include "util/error.h"

#include "util/optget.h"

#include <signal.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#define VERSION "1.0.3"

static struct lop lops[] = {

	{ "help",    ARG_NUL, 256 },

	{ "version", ARG_NUL, 257 },

	{ NULL, 0, 0 }

};

static bool aflag;

static void hlp(void);

static void ver(void);

int main(int ac, char *av[]) { A0 = av[0];

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

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

	case 'a': { aflag = true; break; }

	case 'i': { signal(SIGINT, SIG_IGN); break; }

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

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

	default: { return 1; }

	}

	setvbuf(stdout, NULL, _IONBF, 0);

	bool warned = false;

	FILE **files = (FILE **)malloc(sizeof (FILE) * (unsigned)(ac - opt.ind));

	if (!files) { error(1, "%s", serr()); }

	FILE **f = files;

	for (char **p = &av[opt.ind]; *p; ++p, ++f) {

		*f = fopen(*p, aflag ? "w" : "a");

		if (!*f) { warn("%s: %s", *p, serr()); --f; }

	} *f = NULL;

	char stdbuf[BUFSIZ * 16];

	for (size_t c; (c = fread(stdbuf, 1, sizeof (stdbuf), stdin)) != 0;) {

		for (f = files; *f; ++f) { fwrite(stdbuf, 1, c, *f); }

		fwrite(stdbuf, 1, c, stdout);

	}

	for (f = files; *f; ++f) { if (fclose(*f)) { warn("%s", serr()); }}

	free(files); return warned;

}

static void hlp(void) {

	puts("tee - duplicate standard input");

	puts("usage: tee [-ai] [file...]\n");

	puts("options:");

	puts("  -a         Append to files");

	puts("  -i         Ignore interrupt signals");

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

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

}

static void ver(void) {

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

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

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

}