Thread (21 messages) flat view 21 messages, 5 authors, 2016-06-15

Re: [PATCH] Handle UNC paths everywhere

From: Johannes Sixt <hidden>
Date: 2016-06-15 22:48:06

On Montag, 25. Januar 2010, Robin Rosenberg wrote:
In Windows paths beginning with // are knows as UNC paths. They are
absolute paths, usually referring to a shared resource on a server.

Examples of legal UNC paths

	\\hub\repos\repo
	\\?\unc\hub\repos
	\\?\d:\repo
I agree that that the problem that you are addressing needs a solution.

However, the solution is not a whole-sale replacement of 
have_dos_drive_prefix() by a function that is only a tiny bit fancier. 
Accompanying changes are needed, and perhaps more code locations need change.
quoted hunk ↗ jump to hunk
@@ -648,7 +648,7 @@ int safe_create_leading_directories_const(const char
*path);
 char *enter_repo(char *path, int strict);
 static inline int is_absolute_path(const char *path)
 {
-	return path[0] == '/' || has_dos_drive_prefix(path);
+	return path[0] == '/' || has_win32_abs_prefix(path);
Perhaps we need is_dir_sep(path[0]) here? But since I have not observed any 
breakage in connection with this code, I think that all callers feed only 
normalized paths (i.e. with forward slash). (Note that our getcwd() 
implementation converts backslashes to forward slashes.) This means that a 
full-fledged check is not needed.
quoted hunk ↗ jump to hunk
@@ -5,7 +5,7 @@ char *gitbasename (char *path)
 {
 	const char *base;
 	/* Skip over the disk name in MSDOS pathnames. */
-	if (has_dos_drive_prefix(path))
+	if (has_win32_abs_prefix(path))
 		path += 2;
This change is unnecessary; it really is only to skip an initial driver 
prefix. If you want to support \\?\X: style paths, more work is needed here  
so that you do not return X: or ? as the basename.
+#define has_win32_abs_prefix(path) \
Do we really have to name everything "win32" when it is about Windows?
quoted hunk ↗ jump to hunk
@@ -535,7 +535,7 @@ struct child_process *git_connect(int fd[2], const char
*url_orig,
 		end = host;

 	path = strchr(end, c);
-	if (path && !has_dos_drive_prefix(end)) {
+	if (path && !has_win32_abs_prefix(end)) {
This change is wrong because the check is really only about the drive prefix: 
It checks that we do not mistake c:/foo as a ssh connection to host c, 
path /foo. Yes, it does mean that on Windows we cannot have remotes to hosts 
whose name consists only of a single letter using the rcp notation (you must 
say ssh://c/foo if you mean it).
quoted hunk ↗ jump to hunk
@@ -409,7 +409,7 @@ int normalize_path_copy(char *dst, const char *src)
 {
 	char *dst0;

-	if (has_dos_drive_prefix(src)) {
+	if (has_win32_abs_prefix(src)) {
 		*dst++ = *src++;
 		*dst++ = *src++;
 	}
Is skipping just two characters for \\ or \\?\whatever paths the right thing?
quoted hunk ↗ jump to hunk
@@ -342,7 +342,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 		die_errno("Unable to read current working directory");

 	ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
-	if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
+	if (ceil_offset < 0 && has_win32_abs_prefix(cwd))
 		ceil_offset = 1;
I doubt that this is correct. The purpose of this check is that "c:/" is the 
last directory that is checked (on Unix it would be "/") when path components 
are stripped from cwd. For UNC paths this must be adjusted depending on how 
you want to support \\server\share and \\?\c:\paths: You do not want to check 
whether \\server\.git or \\.git or \\?\.git are git directories.
quoted hunk ↗ jump to hunk
--- a/transport.c
+++ b/transport.c
@@ -797,7 +797,7 @@ static int is_local(const char *url)
 	const char *colon = strchr(url, ':');
 	const char *slash = strchr(url, '/');
 	return !colon || (slash && slash < colon) ||
-		has_dos_drive_prefix(url);
+		has_win32_abs_prefix(url);
This check is again to not mistake c:/foo as rcp style connection. No change 
needed.

As I said, changes to other parts are perhaps also needed, most prominently, 
make_relative_path() that prompted this patch. What about 
make_absolute_path() and make_non_relative_path()?

-- Hannes
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