os: fix os.is_link and os.symlink on windows, add new functions os.getppid, os.getgid, os.getegid (#10251)

vlib/os/os_c.v

@@ -728,7 +728,9 @@ pub fn is_dir(path string) bool {
 // is_link returns a boolean indicating whether `path` is a link.
 pub fn is_link(path string) bool {
 	$if windows {
-		return false // TODO
+		path_ := path.replace('/', '\\')
+		attr := C.GetFileAttributesW(path_.to_wide())
+		return int(attr) != int(C.INVALID_FILE_ATTRIBUTES) && (attr & 0x400) != 0
 	} $else {
 		statbuf := C.stat{}
 		if C.lstat(&char(path.str), &statbuf) != 0 {
@@ -784,26 +786,45 @@ pub fn real_path(fpath string) string {
 	defer {
 		unsafe { free(fullpath) }
 	}
-
+	mut res := ''
 	$if windows {
+		/*
+		// GetFullPathName doesn't work with symbolic links
+		// TODO: TCC32 gets runtime error
+		max := 512
+		size := max * 2 // max_path_len * sizeof(wchar_t)
+		// gets handle with GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0
+		// use get_file_handle instead of C.CreateFile(fpath.to_wide(), 0x80000000, 1, 0, 3, 0x80, 0)
+		// try to open the file to get symbolic link path
+		file := get_file_handle(fpath)
+		if file != voidptr(-1) {
+			fullpath = unsafe { &u16(vcalloc(size)) }
+			// https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfinalpathnamebyhandlew
+			final_len := C.GetFinalPathNameByHandleW(file, fullpath, size, 0)
+			if final_len < size {
+				ret := unsafe { string_from_wide2(fullpath, final_len) }
+				res = ret[4..]
+			} else {
+				eprintln('os.real_path() saw that the file path was too long')
+			}
+		} else {
+		*/
+		// if it is not a file get full path
 		fullpath = unsafe { &u16(vcalloc(max_path_len * 2)) }
 		// TODO: check errors if path len is not enough
 		ret := C.GetFullPathName(fpath.to_wide(), max_path_len, fullpath, 0)
 		if ret == 0 {
 			return fpath
 		}
+		res = unsafe { string_from_wide(fullpath) }
+		//}
+		// C.CloseHandle(file)		
 	} $else {
 		fullpath = vcalloc(max_path_len)
 		ret := &char(C.realpath(&char(fpath.str), &char(fullpath)))
 		if ret == 0 {
 			return fpath
 		}
-	}
-
-	mut res := ''
-	$if windows {
-		res = unsafe { string_from_wide(fullpath) }
-	} $else {
 		res = unsafe { fullpath.vstring() }
 	}
 	nres := normalize_drive_letter(res)

vlib/os/os_nix.c.v

@@ -51,11 +51,19 @@ fn C.uname(name voidptr) int
 
 fn C.symlink(&char, &char) int
 
+fn C.link(&char, &char) int
+
 fn C.gethostname(&char, int) int
 
 // NB: not available on Android fn C.getlogin_r(&char, int) int
 fn C.getlogin() &char
 
+fn C.getppid() int
+
+fn C.getgid() int
+
+fn C.getegid() int
+
 pub fn uname() Uname {
 	mut u := Uname{}
 	utsize := sizeof(C.utsname)
@@ -279,6 +287,14 @@ pub fn symlink(origin string, target string) ?bool {
 	return error(posix_get_error_msg(C.errno))
 }
 
+pub fn link(origin string, target string) ?bool {
+	res := C.link(&char(origin.str), &char(target.str))
+	if res == 0 {
+		return true
+	}
+	return error(posix_get_error_msg(C.errno))
+}
+
 // get_error_msg return error code representation in string.
 pub fn get_error_msg(code int) string {
 	return posix_get_error_msg(code)
@@ -332,6 +348,11 @@ pub fn getpid() int {
 	return C.getpid()
 }
 
+[inline]
+pub fn getppid() int {
+	return C.getppid()
+}
+
 [inline]
 pub fn getuid() int {
 	return C.getuid()
@@ -342,6 +363,16 @@ pub fn geteuid() int {
 	return C.geteuid()
 }
 
+[inline]
+pub fn getgid() int {
+	return C.getgid()
+}
+
+[inline]
+pub fn getegid() int {
+	return C.getegid()
+}
+
 // Turns the given bit on or off, depending on the `enable` parameter
 pub fn posix_set_permission_bit(path_s string, mode u32, enable bool) {
 	mut s := C.stat{}

vlib/os/os_test.v

@@ -311,28 +311,62 @@ fn test_is_writable_folder() {
 }
 
 fn test_make_symlink_check_is_link_and_remove_symlink() {
-	$if windows {
-		// TODO
-		assert true
-		return
-	}
 	folder := 'tfolder'
 	symlink := 'tsymlink'
+	// windows creates a directory symlink, so delete it with rmdir()
+	$if windows {
+		os.rmdir(symlink) or {}
+	} $else {
 		os.rm(symlink) or {}
-	os.rm(folder) or {}
+	}
+	os.rmdir(folder) or {}
 	os.mkdir(folder) or { panic(err) }
 	folder_contents := os.ls(folder) or { panic(err) }
 	assert folder_contents.len == 0
-	os.system('ln -s $folder $symlink')
+	os.symlink(folder, symlink) or { panic(err) }
 	assert os.is_link(symlink)
+	$if windows {
+		os.rmdir(symlink) or { panic(err) }
+	} $else {
 		os.rm(symlink) or { panic(err) }
-	os.rm(folder) or { panic(err) }
+	}
+	os.rmdir(folder) or { panic(err) }
 	folder_exists := os.is_dir(folder)
 	assert folder_exists == false
 	symlink_exists := os.is_link(symlink)
 	assert symlink_exists == false
 }
 
+fn test_make_symlink_check_is_link_and_remove_symlink_with_file() {
+	file := 'tfile'
+	symlink := 'tsymlink'
+	os.rm(symlink) or {}
+	os.rm(file) or {}
+	mut f := os.create(file) or { panic(err) }
+	f.close()
+	os.symlink(file, symlink) or { panic(err) }
+	assert os.is_link(symlink)
+	os.rm(symlink) or { panic(err) }
+	os.rm(file) or { panic(err) }
+	symlink_exists := os.is_link(symlink)
+	assert symlink_exists == false
+}
+
+fn test_make_hardlink_check_is_link_and_remove_hardlink_with_file() {
+	file := 'tfile'
+	symlink := 'tsymlink'
+	os.rm(symlink) or {}
+	os.rm(file) or {}
+	mut f := os.create(file) or { panic(err) }
+	f.close()
+	os.link(file, symlink) or { panic(err) }
+	assert os.exists(symlink)
+	os.rm(symlink) or { panic(err) }
+	os.rm(file) or { panic(err) }
+	symlink_exists := os.is_link(symlink)
+	assert symlink_exists == false
+}
+
 // fn test_fork() {
 // pid := os.fork()
 // if pid == 0 {
@@ -355,16 +389,17 @@ fn test_make_symlink_check_is_link_and_remove_symlink() {
 // }
 // }
 fn test_symlink() {
-	$if windows {
-		return
-	}
 	os.mkdir('symlink') or { panic(err) }
 	os.symlink('symlink', 'symlink2') or { panic(err) }
 	assert os.exists('symlink2')
 	// cleanup
-	os.rm('symlink') or { panic(err) }
+	os.rmdir('symlink') or { panic(err) }
+	$if windows {
+		os.rmdir('symlink2') or { panic(err) }
+	} $else {
 		os.rm('symlink2') or { panic(err) }
 	}
+}
 
 fn test_is_executable_writable_readable() {
 	file_name := 'rwxfile.exe'

vlib/os/os_windows.c.v

@@ -5,6 +5,15 @@ import strings
 #flag windows -l advapi32
 #include <process.h>
 
+// See https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createsymboliclinkw
+fn C.CreateSymbolicLinkW(&u16, &u16, u32) int
+
+// See https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createhardlinkw
+// TCC gets builder error
+// fn C.CreateHardLinkW(&u16, &u16, C.SECURITY_ATTRIBUTES) int
+
+fn C._getpid() int
+
 pub const (
 	path_separator = '\\'
 	path_delimiter = ';'
@@ -138,7 +147,7 @@ pub fn mkdir(path string) ?bool {
 	}
 	apath := real_path(path)
 	if !C.CreateDirectory(apath.to_wide(), 0) {
-		return error('mkdir failed for "$apath", because CreateDirectory returned ' +
+		return error('mkdir failed for "$apath", because CreateDirectory returned: ' +
 			get_error_msg(int(C.GetLastError())))
 	}
 	return true
@@ -310,24 +319,49 @@ pub fn execute(cmd string) Result {
 	}
 }
 
-// See https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createsymboliclinkw
-fn C.CreateSymbolicLinkW(&u16, &u16, u32) int
-
-pub fn symlink(symlink_path string, target_path string) ?bool {
+pub fn symlink(origin string, target string) ?bool {
+	// this is a temporary fix for TCC32 due to runtime error
+	// TODO: patch TCC32
+	$if x64 || x32 {
 		mut flags := 0
-	if is_dir(symlink_path) {
-		flags |= 1
+		if is_dir(origin) {
+			flags ^= 1
 		}
-	flags |= 2 // SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE
-	res := C.CreateSymbolicLinkW(symlink_path.to_wide(), target_path.to_wide(), flags)
-	if res == 0 {
+
+		flags ^= 2 // SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE
+		res := C.CreateSymbolicLinkW(target.to_wide(), origin.to_wide(), flags)
+
+		// 1 = success, != 1 failure => https://stackoverflow.com/questions/33010440/createsymboliclink-on-windows-10
+		if res != 1 {
 			return error(get_error_msg(int(C.GetLastError())))
 		}
-	if !exists(symlink_path) {
+		if !exists(target) {
 			return error('C.CreateSymbolicLinkW reported success, but symlink still does not exist')
 		}
 		return true
 	}
+	return false
+}
+
+pub fn link(origin string, target string) ?bool {
+	/*
+	// TODO: TCC gets builder error
+	res := C.CreateHardLinkW(target.to_wide(), origin.to_wide(), C.NULL)
+	// 1 = success, != 1 failure => https://stackoverflow.com/questions/33010440/createsymboliclink-on-windows-10
+	if res != 1 {
+		return error(get_error_msg(int(C.GetLastError())))
+	}
+	if !exists(target) {
+		return error('C.CreateHardLinkW reported success, but link still does not exist')
+	}
+	return true
+	*/
+	res := execute('fsutil hardlink create $target $origin')
+	if res.exit_code != 0 {
+		return error(res.output)
+	}
+	return true
+}
 
 pub fn (mut f File) close() {
 	if !f.is_opened {
@@ -426,13 +460,36 @@ pub fn is_writable_folder(folder string) ?bool {
 	return true
 }
 
-fn C._getpid() int
-
 [inline]
 pub fn getpid() int {
 	return C._getpid()
 }
 
+[inline]
+pub fn getppid() int {
+	return 0
+}
+
+[inline]
+pub fn getuid() int {
+	return 0
+}
+
+[inline]
+pub fn geteuid() int {
+	return 0
+}
+
+[inline]
+pub fn getgid() int {
+	return 0
+}
+
+[inline]
+pub fn getegid() int {
+	return 0
+}
+
 pub fn posix_set_permission_bit(path_s string, mode u32, enable bool) {
 	// windows has no concept of a permission mask, so do nothing
 }