utils-std

whoami.c (694B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 200809L
#include "../lib/err.h"
#include <errno.h>
#include <pwd.h> // getpwuid
#include <stdio.h>
#include <string.h> // strerror
#include <unistd.h> // geteuid
const char *argv0 = "whoami";
int
main(void)
{
	uid_t euid = geteuid();
	struct passwd *pw = getpwuid(euid);
	if(pw == NULL)
	{
		const char *errstr = strerror(errno);
		if(errno == 0) errstr = "Not Found";
		utils_errx(1, "Failed getting name for user ID %d: %s", euid, errstr);
	}
	puts(pw->pw_name);
	return 0;
}