Refactor php_sys_readlink

Also move the implementation into win32 where it belongs

3 files changed, 169 insertions, 0 deletions

diff --git a/win32/ftok.c b/win32/ftok.c
index 469f2df59a..77de6a0449 100644
--- a/win32/ftok.c
+++ b/win32/ftok.c
@@ -16,6 +16,7 @@
    +----------------------------------------------------------------------+
  */
 
+#include "php.h"
 #include "ipc.h"
 
 #include <windows.h>
diff --git a/win32/ioutil.c b/win32/ioutil.c
index 99eccd511f..0ca01261a5 100644
--- a/win32/ioutil.c
+++ b/win32/ioutil.c
@@ -982,6 +982,138 @@ PW32IO int php_win32_ioutil_fstat(int fd, php_win32_ioutil_stat_t *buf)
 	return php_win32_ioutil_fstat_int((HANDLE)_get_osfhandle(fd), buf, NULL, 0, NULL);
 }/*}}}*/
 
+static ssize_t php_win32_ioutil_readlink_int(HANDLE h, wchar_t *buf, size_t buf_len)
+{/*{{{*/
+	char buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+	PHP_WIN32_IOUTIL_REPARSE_DATA_BUFFER *reparse_data = (PHP_WIN32_IOUTIL_REPARSE_DATA_BUFFER*) buffer;
+	wchar_t* reparse_target;
+	DWORD reparse_target_len;
+	DWORD bytes;
+
+	if (!DeviceIoControl(h,
+		FSCTL_GET_REPARSE_POINT,
+		NULL,
+		0,
+		buffer,
+		sizeof buffer,
+		&bytes,
+		NULL)) {
+		SET_ERRNO_FROM_WIN32_CODE(GetLastError());
+		return -1;
+	}
+
+	if (reparse_data->ReparseTag == IO_REPARSE_TAG_SYMLINK) {
+		/* Real symlink */
+		reparse_target = reparse_data->SymbolicLinkReparseBuffer.ReparseTarget +
+			(reparse_data->SymbolicLinkReparseBuffer.SubstituteNameOffset /
+			sizeof(wchar_t));
+		reparse_target_len =
+			reparse_data->SymbolicLinkReparseBuffer.SubstituteNameLength /
+			sizeof(wchar_t);
+
+		/* Real symlinks can contain pretty much everything, but the only thing we
+		* really care about is undoing the implicit conversion to an NT namespaced
+		* path that CreateSymbolicLink will perform on absolute paths. If the path
+		* is win32-namespaced then the user must have explicitly made it so, and
+		* we better just return the unmodified reparse data. */
+		if (reparse_target_len >= 4 &&
+		reparse_target[0] == L'\\' &&
+		reparse_target[1] == L'?' &&
+		reparse_target[2] == L'?' &&
+		reparse_target[3] == L'\\') {
+			/* Starts with \??\ */
+			if (reparse_target_len >= 6 &&
+				((reparse_target[4] >= L'A' && reparse_target[4] <= L'Z') ||
+				(reparse_target[4] >= L'a' && reparse_target[4] <= L'z')) &&
+				reparse_target[5] == L':' &&
+				(reparse_target_len == 6 || reparse_target[6] == L'\\')) {
+				/* \??\<drive>:\ */
+				reparse_target += 4;
+				reparse_target_len -= 4;
+
+			} else if (reparse_target_len >= 8 &&
+				(reparse_target[4] == L'U' || reparse_target[4] == L'u') &&
+				(reparse_target[5] == L'N' || reparse_target[5] == L'n') &&
+				(reparse_target[6] == L'C' || reparse_target[6] == L'c') &&
+				reparse_target[7] == L'\\') {
+				/* \??\UNC\<server>\<share>\ - make sure the final path looks like
+				* \\<server>\<share>\ */
+				reparse_target += 6;
+				reparse_target[0] = L'\\';
+				reparse_target_len -= 6;
+			}
+		}
+
+	} else if (reparse_data->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT) {
+		/* Junction. */
+		reparse_target = reparse_data->MountPointReparseBuffer.ReparseTarget +
+			(reparse_data->MountPointReparseBuffer.SubstituteNameOffset /
+			sizeof(wchar_t));
+		reparse_target_len = reparse_data->MountPointReparseBuffer.SubstituteNameLength / sizeof(wchar_t);
+
+		/* Only treat junctions that look like \??\<drive>:\ as symlink. Junctions
+		* can also be used as mount points, like \??\Volume{<guid>}, but that's
+		* confusing for programs since they wouldn't be able to actually
+		* understand such a path when returned by uv_readlink(). UNC paths are
+		* never valid for junctions so we don't care about them. */
+		if (!(reparse_target_len >= 6 &&
+			reparse_target[0] == L'\\' &&
+			reparse_target[1] == L'?' &&
+			reparse_target[2] == L'?' &&
+			reparse_target[3] == L'\\' &&
+			((reparse_target[4] >= L'A' && reparse_target[4] <= L'Z') ||
+			(reparse_target[4] >= L'a' && reparse_target[4] <= L'z')) &&
+			reparse_target[5] == L':' &&
+			(reparse_target_len == 6 || reparse_target[6] == L'\\'))) {
+			SET_ERRNO_FROM_WIN32_CODE(ERROR_SYMLINK_NOT_SUPPORTED);
+			return -1;
+		}
+
+		/* Remove leading \??\ */
+		reparse_target += 4;
+		reparse_target_len -= 4;
+
+	} else {
+		/* Reparse tag does not indicate a symlink. */
+		SET_ERRNO_FROM_WIN32_CODE(ERROR_SYMLINK_NOT_SUPPORTED);
+		return -1;
+	}
+
+	if (reparse_target_len >= buf_len) {
+		SET_ERRNO_FROM_WIN32_CODE(ERROR_NOT_ENOUGH_MEMORY);
+		return -1;
+	}
+
+	memcpy(buf, reparse_target, (reparse_target_len + 1)*sizeof(wchar_t));
+
+	return reparse_target_len;
+}/*}}}*/
+
+PW32IO ssize_t php_win32_ioutil_readlink_w(const wchar_t *path, wchar_t *buf, size_t buf_len)
+{/*{{{*/
+	HANDLE h;
+	ssize_t ret;
+
+	h = CreateFileW(path,
+					0,
+					0,
+					NULL,
+					OPEN_EXISTING,
+					FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS,
+					NULL);
+
+	if (h == INVALID_HANDLE_VALUE) {
+		SET_ERRNO_FROM_WIN32_CODE(GetLastError());
+		return -1;
+	}
+
+	ret = php_win32_ioutil_readlink_int(h, buf, buf_len);
+
+	CloseHandle(h);
+
+	return ret;
+}/*}}}*/
+
 /*
  * Local variables:
  * tab-width: 4
diff --git a/win32/ioutil.h b/win32/ioutil.h
index 9da518dbc4..db21c449e0 100644
--- a/win32/ioutil.h
+++ b/win32/ioutil.h
@@ -751,6 +751,42 @@ __forceinline static int php_win32_ioutil_stat_ex(const char *path, php_win32_io
 #define php_win32_ioutil_stat(path, buf) php_win32_ioutil_stat_ex(path, buf, 0)
 #define php_win32_ioutil_lstat(path, buf) php_win32_ioutil_stat_ex(path, buf, 1)
 
+PW32IO ssize_t php_win32_ioutil_readlink_w(const wchar_t *path, wchar_t *buf, size_t buf_len);
+
+__forceinline static ssize_t php_win32_ioutil_readlink(const char *path, char *buf, size_t buf_len)
+{/*{{{*/
+	size_t pathw_len, ret_buf_len;
+	wchar_t *pathw = php_win32_ioutil_conv_any_to_w(path, PHP_WIN32_CP_IGNORE_LEN, &pathw_len);
+	wchar_t retw[PHP_WIN32_IOUTIL_MAXPATHLEN];
+	char *ret_buf;
+	ssize_t ret;
+
+	if (!pathw) {
+		SET_ERRNO_FROM_WIN32_CODE(ERROR_INVALID_PARAMETER);
+		return -1;
+	}
+
+	ret = php_win32_ioutil_readlink_w(pathw, retw, sizeof(retw)-1);
+	if (ret < 0) {
+		DWORD _err = GetLastError();
+		free(pathw);
+		SET_ERRNO_FROM_WIN32_CODE(_err);
+		return ret;
+	}
+
+	ret_buf = php_win32_ioutil_conv_w_to_any(retw, PHP_WIN32_CP_IGNORE_LEN, &ret_buf_len);
+	if (!ret_buf || ret_buf_len >= buf_len || ret_buf_len >= MAXPATHLEN) {
+		free(pathw);
+		SET_ERRNO_FROM_WIN32_CODE(ERROR_BAD_PATHNAME);
+		return -1;
+	}
+	memcpy(buf, ret_buf, ret_buf_len + 1);
+
+	free(pathw);
+
+	return ret;
+}/*}}}*/
+
 #ifdef __cplusplus
 }
 #endif