userspace: Implement uname utility

userspace/programs/CMakeLists.txt

@@ -46,6 +46,7 @@ set(USERSPACE_PROGRAMS
 	Terminal
 	touch
 	u8sum
+	uname
 	whoami
 	WindowServer
 	yes

userspace/programs/uname/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(uname ${SOURCES})
+banan_link_library(uname libc)
+
+install(TARGETS uname OPTIONAL)

userspace/programs/uname/main.cpp

@@ -0,0 +1,90 @@
+#include <getopt.h>
+#include <stdio.h>
+#include <sys/utsname.h>
+
+int main(int argc, char** argv)
+{
+	bool machine = false;
+	bool nodename = false;
+	bool release = false;
+	bool systemname = false;
+	bool version = false;
+
+	for (;;)
+	{
+		static option long_options[] {
+			{ "all",            no_argument, nullptr, 'a' },
+			{ "machine",        no_argument, nullptr, 'm' },
+			{ "kernel-release", no_argument, nullptr, 'r' },
+			{ "nodename",       no_argument, nullptr, 'n' },
+			{ "kernel-name",    no_argument, nullptr, 's' },
+			{ "kernel-version", no_argument, nullptr, 'v' },
+			{ "help",           no_argument, nullptr,  0  },
+		};
+
+		int ch = getopt_long(argc, argv, "amnrsv", long_options, nullptr);
+		if (ch == -1)
+			break;
+
+		switch (ch)
+		{
+			case 0:
+				printf("usage: %s [OPTION]...\n", argv[0]);
+				printf("  -a, --all        print all information\n");
+				printf("  -m, --machine    print machine name\n");
+				printf("  -r, --release    print release\n");
+				printf("  -n, --nodename   print node name\n");
+				printf("  -s, --system     print system name\n");
+				printf("  -v, --version    print version\n");
+				return 0;
+			case 'a':
+				machine = true;
+				nodename = true;
+				release = true;
+				systemname = true;
+				version = true;
+				break;
+			case 'm':
+				machine = true;
+				break;
+			case 'n':
+				nodename = true;
+				break;
+			case 'r':
+				release = true;
+				break;
+			case 's':
+				systemname = true;
+				break;
+			case 'v':
+				version = true;
+				break;
+			case '?':
+				fprintf(stderr, "invalid option %c\n", optopt);
+				fprintf(stderr, "see '%s --help' for usage\n", argv[0]);
+				return 1;
+		}
+	}
+
+	if (!machine && !nodename && !release && !systemname && !version)
+		systemname = true;
+
+	utsname utsname;
+	if (uname(&utsname) == -1)
+	{
+		perror("uname: ");
+		return 1;
+	}
+
+	if (systemname)
+		printf("%s ", utsname.sysname);
+	if (nodename)
+		printf("%s ", utsname.nodename);
+	if (release)
+		printf("%s ", utsname.release);
+	if (version)
+		printf("%s ", utsname.version);
+	if (machine)
+		printf("%s ", utsname.machine);
+	printf("\n");
+}