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mingw: Windows Docker volumes are *not* symbolic links
... even if they may look like them. As looking up the target of the "symbolic link" (just to see whether it starts with `/ContainerMappedDirectories/`) is pretty expensive, we do it when we can be *really* sure that there is a possibility that this might be the case. Signed-off-by: Johannes Schindelin <[email protected]> Signed-off-by: JiSeop Moon <[email protected]>
1 parent 7f5af3b commit 6773f23

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3 files changed

+43
-8
lines changed

3 files changed

+43
-8
lines changed

compat/mingw.c

Lines changed: 19 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -944,7 +944,7 @@ int mingw_lstat(const char *file_name, struct stat *buf)
944944
buf->st_uid = 0;
945945
buf->st_nlink = 1;
946946
buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes,
947-
findbuf.dwReserved0);
947+
findbuf.dwReserved0, file_name);
948948
buf->st_size = S_ISLNK(buf->st_mode) ? MAX_LONG_PATH :
949949
fdata.nFileSizeLow | (((off_t) fdata.nFileSizeHigh) << 32);
950950
buf->st_dev = buf->st_rdev = 0; /* not used by Git */
@@ -995,7 +995,7 @@ static int get_file_info_by_handle(HANDLE hnd, struct stat *buf)
995995
buf->st_gid = 0;
996996
buf->st_uid = 0;
997997
buf->st_nlink = 1;
998-
buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes, 0);
998+
buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes, 0, NULL);
999999
buf->st_size = fdata.nFileSizeLow |
10001000
(((off_t)fdata.nFileSizeHigh)<<32);
10011001
buf->st_dev = buf->st_rdev = 0; /* not used by Git */
@@ -3479,12 +3479,25 @@ int is_inside_windows_container(void)
34793479
return inside_container;
34803480
}
34813481

3482-
int file_attr_to_st_mode (DWORD attr, DWORD tag)
3482+
int file_attr_to_st_mode (DWORD attr, DWORD tag, const char *path)
34833483
{
34843484
int fMode = S_IREAD;
3485-
if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) && tag == IO_REPARSE_TAG_SYMLINK)
3486-
fMode |= S_IFLNK;
3487-
else if (attr & FILE_ATTRIBUTE_DIRECTORY)
3485+
if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) &&
3486+
tag == IO_REPARSE_TAG_SYMLINK) {
3487+
int flag = S_IFLNK;
3488+
char buf[MAX_LONG_PATH];
3489+
3490+
/*
3491+
* Windows containers' mapped volumes are marked as reparse
3492+
* points and look like symbolic links, but they are not.
3493+
*/
3494+
if (path && is_inside_windows_container() &&
3495+
readlink(path, buf, sizeof(buf)) > 27 &&
3496+
starts_with(buf, "/ContainerMappedDirectories/"))
3497+
flag = S_IFDIR;
3498+
3499+
fMode |= flag;
3500+
} else if (attr & FILE_ATTRIBUTE_DIRECTORY)
34883501
fMode |= S_IFDIR;
34893502
else
34903503
fMode |= S_IFREG;

compat/win32.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
#include <windows.h>
77
#endif
88

9-
extern int file_attr_to_st_mode (DWORD attr, DWORD tag);
9+
extern int file_attr_to_st_mode (DWORD attr, DWORD tag, const char *path);
1010

1111
static inline int get_file_attr(const char *fname, WIN32_FILE_ATTRIBUTE_DATA *fdata)
1212
{

compat/win32/fscache.c

Lines changed: 23 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -194,7 +194,29 @@ static struct fsentry *fseentry_create_entry(struct fscache *cache,
194194
fdata->FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT ?
195195
fdata->EaSize : 0;
196196

197-
fse->st_mode = file_attr_to_st_mode(fdata->FileAttributes, fdata->EaSize);
197+
/*
198+
* On certain Windows versions, host directories mapped into
199+
* Windows Containers ("Volumes", see https://docs.docker.com/storage/volumes/)
200+
* look like symbolic links, but their targets are paths that
201+
* are valid only in kernel mode.
202+
*
203+
* Let's work around this by detecting that situation and
204+
* telling Git that these are *not* symbolic links.
205+
*/
206+
if (fse->reparse_tag == IO_REPARSE_TAG_SYMLINK &&
207+
sizeof(buf) > (list ? list->len + 1 : 0) + fse->len + 1 &&
208+
is_inside_windows_container()) {
209+
size_t off = 0;
210+
if (list) {
211+
memcpy(buf, list->dirent.d_name, list->len);
212+
buf[list->len] = '/';
213+
off = list->len + 1;
214+
}
215+
memcpy(buf + off, fse->dirent.d_name, fse->len);
216+
buf[off + fse->len] = '\0';
217+
}
218+
219+
fse->st_mode = file_attr_to_st_mode(fdata->FileAttributes, fdata->EaSize, buf);
198220
fse->dirent.d_type = S_ISREG(fse->st_mode) ? DT_REG :
199221
S_ISDIR(fse->st_mode) ? DT_DIR : DT_LNK;
200222
fse->u.s.st_size = S_ISLNK(fse->st_mode) ? MAX_LONG_PATH :

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