On 01.02.21 09:18, AKASHI Takahiro wrote:
On Sun, Jan 31, 2021 at 12:09:53AM +0100, Heinrich Schuchardt wrote:
The FAT32 File System Specification [1] requires leading and trailing spaces as well as trailing periods of long names to be ignored.
This renders a test for '.' and '..' as file name superfluous.
But we must check that the resulting name has at least one character.
[1] Microsoft Extensible Firmware Initiative FAT32 File System Specification Version 1.03, December 6, 2000 Microsoft Corporation https://www.win.tue.nl/~aeb/linux/fs/fat/fatgen103.pdf
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de
fs/fat/fat_write.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 0f4786ef0f..1b0a0eda09 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -1237,12 +1237,32 @@ again: }
*last_slash_cont = '\0';
*basename = last_slash_cont + 1;
filename = last_slash_cont + 1;
*basename = filename;
- /*
* The FAT32 File System Specification v1.03 requires leading and* trailing spaces as well as trailing periods to be ignored.*/- for (; *filename == ' '; ++filename)
;- /* Remove trailing periods and spaces */
- for (p = filename + strlen(filename) - 1; p >= filename; --p) {
switch (*p) {case ' ':case '.':*p = 0;break;default:goto done;}- }
Given the semantics of the functions, split_filename() and normalize_longname(), the code you added above should be moved to normalize_longname().
normalize_longname(l_filename, filename) converts the argument filename to a lowercase string l_filename. The parameter filename remains unchanged. But it is the value of filename that is used to create the new directory entry in file_fat_write_at() and fat_mkdir().
So moving the change to normalize_longname() will not lead to the intended behavior.
Removing leading and trailing blanks fits well into the task of split_filename to identify the actual file name.
Best regards
Heinrich
+done:
- *basename = filename;
- return 0;
}
@@ -1260,10 +1280,7 @@ static int normalize_longname(char *l_filename, const char *filename) { const char *p, illegal[] = "<>:"/\|?*";
- if (!strcmp(filename, ".") || !strcmp(filename, ".."))
return -1;It would be better for the check above to remain here as "." and ".." are legal directory names. (I even think it would be best to move it to the caller, file_fat_write_at() or fat_mkdir().)
I think that the suggested sequence would be more intuitive for better understanding of what Windows requirements say.
-Takahiro Akashi
- if (strlen(filename) >= VFAT_MAXLEN_BYTES)
if (!*filename || strlen(filename) >= VFAT_MAXLEN_BYTES) return -1;
for (p = filename; *p; ++p) {
-- 2.29.2