netd: add hostname command

tools/netd/Makefile

@@ -1,14 +1,22 @@
 .phony: all install
 CC=x86_64-astral-gcc
 LD=x86_64-astral-gcc
-all: netd
+all: netd hostname
 
 install:
 	mkdir -p "$(DESTDIR)/$(PREFIX)/sbin/"
+	mkdir -p "$(DESTDIR)/$(PREFIX)/bin/"
 	cp netd "$(DESTDIR)/$(PREFIX)/sbin/netd"
+	cp hostname "$(DESTDIR)/$(PREFIX)/bin/hostname"
 
 netd: main.o
 	$(LD) $(LDFLAGS) -g -o $@ $^
 
+hostname: hostname.o
+	$(LD) $(LDFLAGS) -g -o $@ $^
+
 main.o: main.c
 	$(CC) -c $(CFLAGS) -g -o $@ $<
+
+hostname.o: hostname.c
+	$(CC) -c $(CFLAGS) -g -o $@ $<

tools/netd/hostname.c

@@ -0,0 +1,29 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+	char hostname[1000];
+
+	if (argc == 1) {
+		if (gethostname(hostname, 1000)) {
+			fprintf(stderr, "%s: failed to get hostname: %s\n", argv[0], strerror(errno));
+			return EXIT_FAILURE;
+		}
+
+		printf("%s\n", hostname);
+	} else if (argc == 2) {
+		if (sethostname(argv[1], strlen(argv[1]))) {
+			fprintf(stderr, "%s: failed to set hostname: %s\n", argv[0], strerror(errno));
+			return EXIT_FAILURE;
+		}
+	} else {
+		fprintf(stderr, "%s: usage: %s [hostname]\n", argv[0], argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}