micro-utils/src/coreutils/readlink/readlink.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>

int main(int argc, char **argv) {
	char n_flag = 0;

	int opt;
	while ((opt = getopt(argc, argv, "n")) != -1) {
		switch (opt) {
			case 'n':
				n_flag = 1;
				break;

			default:
				puts("readlink [n] [file1 file2...]\n\t-n Don't add newline");
				return 0;
		}
	}

	argv += optind;
	argc -= optind;

	for (int i = 0; i < argc; i++) {
		char path[PATH_MAX + 1];
		ssize_t r = readlink(argv[i], path, sizeof(path));
		if (r < 0) {
			fprintf(stderr, "readlink: %s: %s\n", argv[i], strerror(errno));
			return 1;
		}

		if (r > (ssize_t)sizeof(path)) {
			fprintf(stderr, "readlink: %s: path too long\n", argv[i]);
			return 1;
		}

		if (n_flag)
			fputs(path, stdout);

		else
			puts(path);
	}

	return 0;
}