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-rw-r--r--path.c96
1 files changed, 68 insertions, 28 deletions
diff --git a/path.c b/path.c
index 7f109f6..9a4b9e7 100644
--- a/path.c
+++ b/path.c
@@ -1290,37 +1290,77 @@ int daemon_avoid_alias(const char *p)
}
}
-static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
+/*
+ * On NTFS, we need to be careful to disallow certain synonyms of the `.git/`
+ * directory:
+ *
+ * - For historical reasons, file names that end in spaces or periods are
+ * automatically trimmed. Therefore, `.git . . ./` is a valid way to refer
+ * to `.git/`.
+ *
+ * - For other historical reasons, file names that do not conform to the 8.3
+ * format (up to eight characters for the basename, three for the file
+ * extension, certain characters not allowed such as `+`, etc) are associated
+ * with a so-called "short name", at least on the `C:` drive by default.
+ * Which means that `git~1/` is a valid way to refer to `.git/`.
+ *
+ * Note: Technically, `.git/` could receive the short name `git~2` if the
+ * short name `git~1` were already used. In Git, however, we guarantee that
+ * `.git` is the first item in a directory, therefore it will be associated
+ * with the short name `git~1` (unless short names are disabled).
+ *
+ * - For yet other historical reasons, NTFS supports so-called "Alternate Data
+ * Streams", i.e. metadata associated with a given file, referred to via
+ * `<filename>:<stream-name>:<stream-type>`. There exists a default stream
+ * type for directories, allowing `.git/` to be accessed via
+ * `.git::$INDEX_ALLOCATION/`.
+ *
+ * When this function returns 1, it indicates that the specified file/directory
+ * name refers to a `.git` file or directory, or to any of these synonyms, and
+ * Git should therefore not track it.
+ *
+ * For performance reasons, _all_ Alternate Data Streams of `.git/` are
+ * forbidden, not just `::$INDEX_ALLOCATION`.
+ *
+ * This function is intended to be used by `git fsck` even on platforms where
+ * the backslash is a regular filename character, therefore it needs to handle
+ * backlash characters in the provided `name` specially: they are interpreted
+ * as directory separators.
+ */
+int is_ntfs_dotgit(const char *name)
{
- if (len < skip)
+ char c;
+
+ /*
+ * Note that when we don't find `.git` or `git~1` we end up with `name`
+ * advanced partway through the string. That's okay, though, as we
+ * return immediately in those cases, without looking at `name` any
+ * further.
+ */
+ c = *(name++);
+ if (c == '.') {
+ /* .git */
+ if (((c = *(name++)) != 'g' && c != 'G') ||
+ ((c = *(name++)) != 'i' && c != 'I') ||
+ ((c = *(name++)) != 't' && c != 'T'))
+ return 0;
+ } else if (c == 'g' || c == 'G') {
+ /* git ~1 */
+ if (((c = *(name++)) != 'i' && c != 'I') ||
+ ((c = *(name++)) != 't' && c != 'T') ||
+ *(name++) != '~' ||
+ *(name++) != '1')
+ return 0;
+ } else
return 0;
- len -= skip;
- path += skip;
- while (len-- > 0) {
- char c = *(path++);
- if (c != ' ' && c != '.')
+
+ for (;;) {
+ c = *(name++);
+ if (!c || c == '\\' || c == '/' || c == ':')
+ return 1;
+ if (c != '.' && c != ' ')
return 0;
}
- return 1;
-}
-
-int is_ntfs_dotgit(const char *name)
-{
- size_t len;
-
- for (len = 0; ; len++)
- if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
- if (only_spaces_and_periods(name, len, 4) &&
- !strncasecmp(name, ".git", 4))
- return 1;
- if (only_spaces_and_periods(name, len, 5) &&
- !strncasecmp(name, "git~1", 5))
- return 1;
- if (name[len] != '\\')
- return 0;
- name += len + 1;
- len = -1;
- }
}
static int is_ntfs_dot_generic(const char *name,
@@ -1336,7 +1376,7 @@ static int is_ntfs_dot_generic(const char *name,
only_spaces_and_periods:
for (;;) {
char c = name[i++];
- if (!c)
+ if (!c || c == ':')
return 1;
if (c != ' ' && c != '.')
return 0;