From cfdbf15bfc481fc4e9a46086d62642f86b2a0478 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Sun, 22 Oct 2023 15:17:00 +0300
Subject: [PATCH] hostname add

---
 coreutils/hostname.c | 80 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 coreutils/hostname.c

diff --git a/coreutils/hostname.c b/coreutils/hostname.c
new file mode 100644
index 0000000..dbd641e
--- /dev/null
+++ b/coreutils/hostname.c
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <limits.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+int main(const int argc, const char **argv) {
+	unsigned int f_flag = 0;
+	unsigned int d_flag = 0;
+	unsigned int i_flag = 0;
+
+	int i;
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] != '-')
+			break;
+
+		else if (!strcmp(argv[i], "-f"))
+			f_flag = 1;
+
+		else if (!strcmp(argv[i], "-d"))
+			d_flag = 1;
+
+		else if (!strcmp(argv[i], "-i"))
+			i_flag = 1;
+
+		else if (!strcmp(argv[i], "--help")) {
+			printf("hostname [-f (Display the FQDN)] [-d (Display domainname)] [-i (Addresses for the hostname)]/ [hostname (Set new hostname)]\n");
+			return 0;
+		}
+	}
+
+
+	/* Set hostname */
+	if (argc - i == 1) {
+		if (sethostname(argv[argc - 1], strlen(argv[argc - 1])) < 0) {
+			fprintf(stderr, "hostname: %s\n", strerror(errno));
+			return 1;
+		}
+
+		return 0;
+	}
+
+	/* Get info */
+	char hostname[HOST_NAME_MAX];
+	if (gethostname(hostname, sizeof(hostname)) < 0) {
+		fprintf(stderr, "hostname: %s\n", strerror(errno));
+		return 1;
+	}
+
+
+	struct hostent *hp = gethostbyname(hostname);
+	if (!hp) {
+		fprintf(stderr, "hostname: %s\n", strerror(errno));
+		return 1;
+	}
+
+	/* Print info */
+	if (f_flag)
+		puts(hp->h_name);
+
+	else if (d_flag) {
+		char *ptr = strchr(hp->h_name, '.');
+		if (ptr)
+			puts(ptr + 1);
+	}
+
+	else if (i_flag) {
+		while (hp->h_addr_list[0])
+			printf("%s ", inet_ntoa( *(struct in_addr *) *(hp->h_addr_list++) ));
+		printf("\n");
+	}
+
+	else
+		puts(hostname);
+
+	return 0;
+}