From 9daf2206161dc8322852c541136e20e193c76f20 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 7 Dec 2018 13:39:30 +0100
Subject: [PATCH] clean: do not traverse mount points
It seems to be not exactly rare on Windows to install NTFS junction
points (the equivalent of "bind mounts" on Linux/Unix) in worktrees,
e.g. to map some development tools into a subdirectory.
In such a scenario, it is pretty horrible if `git clean -dfx` traverses
into the mapped directory and starts to "clean up".
Let's just not do that. Let's make sure before we traverse into a
directory that it is not a mount point (or junction).
This addresses https://github.com/git-for-windows/git/issues/607
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
builtin/clean.c | 14 ++++++++++++++
compat/mingw.c | 22 ++++++++++++++++++++++
compat/mingw.h | 3 +++
git-compat-util.h | 4 ++++
path.c | 39 +++++++++++++++++++++++++++++++++++++++
path.h | 1 +
t/t7300-clean.sh | 9 +++++++++
7 files changed, 92 insertions(+)
diff --git a/builtin/clean.c b/builtin/clean.c
index 9c48dd02711c6e..ef12aecbb177f9 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -37,6 +37,8 @@ static const char *msg_remove = N_("Removing %s\n");
static const char *msg_would_remove = N_("Would remove %s\n");
static const char *msg_skip_git_dir = N_("Skipping repository %s\n");
static const char *msg_would_skip_git_dir = N_("Would skip repository %s\n");
+static const char *msg_skip_mount_point = N_("Skipping mount point %s\n");
+static const char *msg_would_skip_mount_point = N_("Would skip mount point %s\n");
static const char *msg_warn_remove_failed = N_("failed to remove %s");
static const char *msg_warn_lstat_failed = N_("could not lstat %s\n");
static const char *msg_skip_cwd = N_("Refusing to remove current working directory\n");
@@ -181,6 +183,18 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
goto out;
}
+ if (is_mount_point(path)) {
+ if (!quiet) {
+ quote_path(path->buf, prefix, "ed, 0);
+ printf(dry_run ?
+ _(msg_would_skip_mount_point) :
+ _(msg_skip_mount_point), quoted.buf);
+ }
+ *dir_gone = 0;
+
+ goto out;
+ }
+
dir = opendir(path->buf);
if (!dir) {
/* an empty dir could be removed even if it is unreadble */
diff --git a/compat/mingw.c b/compat/mingw.c
index 63f36c893bfe96..bcf97cb6a97832 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2685,6 +2685,28 @@ pid_t waitpid(pid_t pid, int *status, int options)
return -1;
}
+int mingw_is_mount_point(struct strbuf *path)
+{
+ WIN32_FIND_DATAW findbuf = { 0 };
+ HANDLE handle;
+ wchar_t wfilename[MAX_PATH];
+ int wlen = xutftowcs_path(wfilename, path->buf);
+ if (wlen < 0)
+ die(_("could not get long path for '%s'"), path->buf);
+
+ /* remove trailing slash, if any */
+ if (wlen > 0 && wfilename[wlen - 1] == L'/')
+ wfilename[--wlen] = L'\0';
+
+ handle = FindFirstFileW(wfilename, &findbuf);
+ if (handle == INVALID_HANDLE_VALUE)
+ return 0;
+ FindClose(handle);
+
+ return (findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
+ (findbuf.dwReserved0 == IO_REPARSE_TAG_MOUNT_POINT);
+}
+
int xutftowcsn(wchar_t *wcs, const char *utfs, size_t wcslen, int utflen)
{
int upos = 0, wpos = 0;
diff --git a/compat/mingw.h b/compat/mingw.h
index ebfb8ba423b754..92830de32a40e3 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -454,6 +454,9 @@ static inline void convert_slashes(char *path)
if (*path == '\\')
*path = '/';
}
+struct strbuf;
+int mingw_is_mount_point(struct strbuf *path);
+#define is_mount_point mingw_is_mount_point
#define PATH_SEP ';'
char *mingw_query_user_email(void);
#define query_user_email mingw_query_user_email
diff --git a/git-compat-util.h b/git-compat-util.h
index a06d4f3809e566..6feb46853b66dd 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -616,6 +616,10 @@ static inline int git_has_dir_sep(const char *path)
#define has_dir_sep(path) git_has_dir_sep(path)
#endif
+#ifndef is_mount_point
+#define is_mount_point is_mount_point_via_stat
+#endif
+
#ifndef query_user_email
#define query_user_email() NULL
#endif
diff --git a/path.c b/path.c
index 4dcf3c8d40db12..59e191517ea0b5 100644
--- a/path.c
+++ b/path.c
@@ -1226,6 +1226,45 @@ char *strip_path_suffix(const char *path, const char *suffix)
return offset == -1 ? NULL : xstrndup(path, offset);
}
+int is_mount_point_via_stat(struct strbuf *path)
+{
+ size_t len = path->len;
+ unsigned int current_dev;
+ struct stat st;
+
+ if (!strcmp("/", path->buf))
+ return 1;
+
+ strbuf_addstr(path, "/.");
+ if (lstat(path->buf, &st)) {
+ /*
+ * If we cannot access the current directory, we cannot say
+ * that it is a bind mount.
+ */
+ strbuf_setlen(path, len);
+ return 0;
+ }
+ current_dev = st.st_dev;
+
+ /* Now look at the parent directory */
+ strbuf_addch(path, '.');
+ if (lstat(path->buf, &st)) {
+ /*
+ * If we cannot access the parent directory, we cannot say
+ * that it is a bind mount.
+ */
+ strbuf_setlen(path, len);
+ return 0;
+ }
+ strbuf_setlen(path, len);
+
+ /*
+ * If the device ID differs between current and parent directory,
+ * then it is a bind mount.
+ */
+ return current_dev != st.st_dev;
+}
+
int daemon_avoid_alias(const char *p)
{
int sl, ndot;
diff --git a/path.h b/path.h
index 5f6c85e5f8d795..9b0b5d2718e5f8 100644
--- a/path.h
+++ b/path.h
@@ -183,6 +183,7 @@ int normalize_path_copy(char *dst, const char *src);
int strbuf_normalize_path(struct strbuf *src);
int longest_ancestor_length(const char *path, struct string_list *prefixes);
char *strip_path_suffix(const char *path, const char *suffix);
+int is_mount_point_via_stat(struct strbuf *path);
int daemon_avoid_alias(const char *path);
/*
diff --git a/t/t7300-clean.sh b/t/t7300-clean.sh
index 00d4070156243b..7c3a1ca91df534 100755
--- a/t/t7300-clean.sh
+++ b/t/t7300-clean.sh
@@ -800,4 +800,13 @@ test_expect_success 'traverse into directories that may have ignored entries' '
)
'
+test_expect_success MINGW 'clean does not traverse mount points' '
+ mkdir target &&
+ >target/dont-clean-me &&
+ git init with-mountpoint &&
+ cmd //c "mklink /j with-mountpoint\\mountpoint target" &&
+ git -C with-mountpoint clean -dfx &&
+ test_path_is_file target/dont-clean-me
+'
+
test_done