path: bump most Win32 unicode buffer sizes from MAX_PATH to GIT_PATH_MAX

ianhattendorf · ethomson · commit 69c65b9a45d5 · 2021-05-05T23:13:35.000+01:00
diff --git a/src/win32/path_w32.c b/src/win32/path_w32.c
@@ -170,7 +170,7 @@ static int win32_path_cwd(wchar_t *out, size_t len)
 		 * '\'s, but we we add a 'UNC' specifier to the path, plus
 		 * a trailing directory separator, plus a NUL.
 		 */
-		if (cwd_len > MAX_PATH - 4) {
+		if (cwd_len > GIT_WIN_PATH_MAX - 4) {
 			errno = ENAMETOOLONG;
 			return -1;
 		}
@@ -187,7 +187,7 @@ static int win32_path_cwd(wchar_t *out, size_t len)
 	 * working directory.  (One character for the directory separator,
 	 * one for the null.
 	 */
-	else if (cwd_len > MAX_PATH - 2) {
+	else if (cwd_len > GIT_WIN_PATH_MAX - 2) {
 		errno = ENAMETOOLONG;
 		return -1;
 	}
@@ -205,13 +205,13 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 
 	/* See if this is an absolute path (beginning with a drive letter) */
 	if (git_path_is_absolute(src)) {
-		if (git__utf8_to_16(dest, MAX_PATH, src) < 0)
+		if (git__utf8_to_16(dest, GIT_WIN_PATH_MAX, src) < 0)
 			goto on_error;
 	}
 	/* File-prefixed NT-style paths beginning with \\?\ */
 	else if (path__is_nt_namespace(src)) {
 		/* Skip the NT prefix, the destination already contains it */
-		if (git__utf8_to_16(dest, MAX_PATH, src + PATH__NT_NAMESPACE_LEN) < 0)
+		if (git__utf8_to_16(dest, GIT_WIN_PATH_MAX, src + PATH__NT_NAMESPACE_LEN) < 0)
 			goto on_error;
 	}
 	/* UNC paths */
@@ -220,12 +220,12 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 		dest += 4;
 
 		/* Skip the leading "\\" */
-		if (git__utf8_to_16(dest, MAX_PATH - 2, src + 2) < 0)
+		if (git__utf8_to_16(dest, GIT_WIN_PATH_MAX - 2, src + 2) < 0)
 			goto on_error;
 	}
 	/* Absolute paths omitting the drive letter */
 	else if (path__startswith_slash(src)) {
-		if (path__cwd(dest, MAX_PATH) < 0)
+		if (path__cwd(dest, GIT_WIN_PATH_MAX) < 0)
 			goto on_error;
 
 		if (!git_path_is_absolute(dest)) {
@@ -234,19 +234,19 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 		}
 
 		/* Skip the drive letter specification ("C:") */
-		if (git__utf8_to_16(dest + 2, MAX_PATH - 2, src) < 0)
+		if (git__utf8_to_16(dest + 2, GIT_WIN_PATH_MAX - 2, src) < 0)
 			goto on_error;
 	}
 	/* Relative paths */
 	else {
 		int cwd_len;
 
-		if ((cwd_len = win32_path_cwd(dest, MAX_PATH)) < 0)
+		if ((cwd_len = win32_path_cwd(dest, GIT_WIN_PATH_MAX)) < 0)
 			goto on_error;
 
 		dest[cwd_len++] = L'\\';
 
-		if (git__utf8_to_16(dest + cwd_len, MAX_PATH - cwd_len, src) < 0)
+		if (git__utf8_to_16(dest + cwd_len, GIT_WIN_PATH_MAX - cwd_len, src) < 0)
 			goto on_error;
 	}
 
@@ -273,7 +273,7 @@ int git_win32_path_relative_from_utf8(git_win32_path out, const char *src)
 		return git_win32_path_from_utf8(out, src);
 	}
 
-	if ((len = git__utf8_to_16(dest, MAX_PATH, src)) < 0)
+	if ((len = git__utf8_to_16(dest, GIT_WIN_PATH_MAX, src)) < 0)
 		return -1;
 
 	for (p = dest; p < (dest + len); p++) {
diff --git a/src/win32/w32_common.h b/src/win32/w32_common.h
@@ -8,24 +8,33 @@
 #ifndef INCLUDE_win32_w32_common_h__
 #define INCLUDE_win32_w32_common_h__
 
+#include <git2/common.h>
+
+/*
+ * 4096 is the max allowed Git path. `MAX_PATH` (260) is the typical max allowed
+ * Windows path length, however win32 Unicode APIs generally allow up to 32,767
+ * if prefixed with "\\?\" (i.e. converted to an NT-style name).
+ */
+#define GIT_WIN_PATH_MAX GIT_PATH_MAX
+
 /*
- * Provides a large enough buffer to support Windows paths:  MAX_PATH is
- * 260, corresponding to a maximum path length of 259 characters plus a
- * NULL terminator.  Prefixing with "\\?\" adds 4 characters, but if the
- * original was a UNC path, then we turn "\\server\share" into
+ * Provides a large enough buffer to support Windows Git paths:
+ * GIT_WIN_PATH_MAX is 4096, corresponding to a maximum path length of 4095
+ * characters plus a NULL terminator.  Prefixing with "\\?\" adds 4 characters,
+ * but if the original was a UNC path, then we turn "\\server\share" into
  * "\\?\UNC\server\share".  So we replace the first two characters with
- * 8 characters, a net gain of 6, so the maximum length is MAX_PATH+6.
+ * 8 characters, a net gain of 6, so the maximum length is GIT_WIN_PATH_MAX+6.
  */
-#define GIT_WIN_PATH_UTF16		MAX_PATH+6
+#define GIT_WIN_PATH_UTF16		GIT_WIN_PATH_MAX+6
 
-/* Maximum size of a UTF-8 Win32 path.  We remove the "\\?\" or "\\?\UNC\"
- * prefixes for presentation, bringing us back to 259 (non-NULL)
+/* Maximum size of a UTF-8 Win32 Git path.  We remove the "\\?\" or "\\?\UNC\"
+ * prefixes for presentation, bringing us back to 4095 (non-NULL)
  * characters.  UTF-8 does have 4-byte sequences, but they are encoded in
  * UTF-16 using surrogate pairs, which takes up the space of two characters.
  * Two characters in the range U+0800 -> U+FFFF take up more space in UTF-8
  * (6 bytes) than one surrogate pair (4 bytes).
  */
-#define GIT_WIN_PATH_UTF8		(259 * 3 + 1)
+#define GIT_WIN_PATH_UTF8		((GIT_WIN_PATH_MAX - 1) * 3 + 1)
 
 /*
  * The length of a Windows "shortname", for 8.3 compatibility.
diff --git a/tests/path/win32.c b/tests/path/win32.c
@@ -78,13 +78,11 @@ void test_path_win32__honors_max_path(void)
 #ifdef GIT_WIN32
 	git_win32_path path_utf16;
 
-	test_utf8_to_utf16("C:\\This path is 259 chars and is the max length in windows\\0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij",
-		L"\\\\?\\C:\\This path is 259 chars and is the max length in windows\\0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij");
-	test_utf8_to_utf16("\\\\unc\\paths may also be 259 characters including the server\\123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij",
-		L"\\\\?\\UNC\\unc\\paths may also be 259 characters including the server\\123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij");
+	test_utf8_to_utf16("C:\\This path is 261 characters which is fine for our path handling functions which cope with paths longer than MAX_PATH\\0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghijk",
+		L"\\\\?\\C:\\This path is 261 characters which is fine for our path handling functions which cope with paths longer than MAX_PATH\\0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghijk");
+
+	cl_check_fail(git_win32_path_from_utf8(path_utf16, "C:\\This path is 4097 chars and exceeds our maximum path length on Windows which is limited to 4096 characters\\alas\\0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij01"));
 
-	cl_check_fail(git_win32_path_from_utf8(path_utf16, "C:\\This path is 260 chars and is sadly too long for windows\\0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij"));
-	cl_check_fail(git_win32_path_from_utf8(path_utf16, "\\\\unc\\paths are also bound by 260 character restrictions\\including the server name portion\\bcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij"));
 #endif
 }
 
diff --git a/tests/win32/longpath.c b/tests/win32/longpath.c
@@ -33,33 +33,13 @@ void test_win32_longpath__cleanup(void)
 	cl_git_sandbox_cleanup();
 }
 
-#ifdef GIT_WIN32
-void assert_name_too_long(void)
-{
-	const git_error *err;
-	size_t expected_len, actual_len;
-	char *expected_msg;
-
-	err = git_error_last();
-	actual_len = strlen(err->message);
-
-	expected_msg = git_win32_get_error_message(ERROR_FILENAME_EXCED_RANGE);
-	expected_len = strlen(expected_msg);
-
-	/* check the suffix */
-	cl_assert_equal_s(expected_msg, err->message + (actual_len - expected_len));
-
-	git__free(expected_msg);
-}
-#endif
-
 void test_win32_longpath__errmsg_on_checkout(void)
 {
 #ifdef GIT_WIN32
 	git_repository *repo;
 
 	cl_git_fail(git_clone(&repo, cl_fixture("testrepo.git"), path.ptr, NULL));
-	assert_name_too_long();
+	cl_assert(git__prefixcmp(git_error_last()->message, "path too long") == 0);
 #endif
 }
 
