os: create os.hostname() and os.chown() + os.uname() for windows (#9722)

vlib/os/os_c.v

@@ -31,6 +31,8 @@ fn C.CopyFile(&u16, &u16, bool) int
 
 fn C._wstat64(&char, voidptr) u64
 
+fn C.chown(&char, int, int) int
+
 // fn C.proc_pidpath(int, byteptr, int) int
 struct C.stat {
 	st_size  u64
@@ -827,7 +829,24 @@ pub fn flush() {
 // chmod change file access attributes of `path` to `mode`.
 // Octals like `0o600` can be used.
 pub fn chmod(path string, mode int) {
-	C.chmod(&char(path.str), mode)
+	if C.chmod(&char(path.str), mode) != 0 {
+		panic(posix_get_error_msg(C.errno))
+	}
+}
+
+// chown change owner and group attributes of path to `owner` and `group`.
+pub fn chown(path string, owner int, group int) ? {
+	$if windows {
+		return error('os.chown() not implemented for Windows')
+	} $else {
+		if owner < 0 || group < 0 {
+			return error('os.chown() uid and gid cannot be negative: Not changing owner!')
+		} else {
+			if C.chown(&char(path.str), owner, group) != 0 {
+				return error_with_code(posix_get_error_msg(C.errno), C.errno)
+			}
+		}
+	}
 }
 
 // open_append opens `path` file for appending.

vlib/os/os_nix.c.v

@@ -51,6 +51,8 @@ fn C.uname(name voidptr) int
 
 fn C.symlink(&char, &char) int
 
+fn C.gethostname(&char, int) int
+
 pub fn uname() Uname {
 	mut u := Uname{}
 	utsize := sizeof(C.utsname)
@@ -69,6 +71,18 @@ pub fn uname() Uname {
 	return u
 }
 
+pub fn hostname() string {
+	mut hstnme := ''
+	size := 256
+	mut buf := unsafe { &char(malloc(size)) }
+	if C.gethostname(buf, size) == 0 {
+		hstnme = unsafe { cstring_to_vstring(buf) }
+		unsafe { free(buf) }
+		return hstnme
+	}
+	return ''
+}
+
 fn init_os_args(argc int, argv &&byte) []string {
 	mut args_ := []string{}
 	// mut args := []string(make(0, argc, sizeof(string)))

vlib/os/os_windows.c.v

@@ -376,17 +376,24 @@ pub fn debugger_present() bool {
 }
 
 pub fn uname() Uname {
-	// TODO: implement `os.uname()` for windows
-	unknown := 'unknown'
+	// TODO: use Win32 Api functions instead
+	sys_and_ver := execute('cmd /c ver').output.split('[')
+	nodename := execute('cmd /c hostname').output
+	machine := execute('cmd /c echo %PROCESSOR_ARCHITECTURE%').output
 	return Uname{
-		sysname: unknown
-		nodename: unknown
-		release: unknown
-		version: unknown
-		machine: unknown
+		sysname: sys_and_ver[0].trim_space()
+		nodename: nodename
+		release: sys_and_ver[1].replace(']', '')
+		version: sys_and_ver[0] + '[' + sys_and_ver[1]
+		machine: machine
 	}
 }
 
+pub fn hostname() string {
+	// TODO: use C.GetComputerName(&u16, u32) int instead
+	return execute('cmd /c hostname').output
+}
+
 // `is_writable_folder` - `folder` exists and is writable to the process
 pub fn is_writable_folder(folder string) ?bool {
 	if !exists(folder) {