[U-Boot] [PATCH v3 8/9] fs/fat: fix case for FAT shortnames

Rob Clark
2017-09-10T11:21:33Z

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Noticed when comparing our output to linux. There are some lcase bits
which control whether filename and/or extension should be downcase'd.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Łukasz Majewski <lukma@denx.de>
---
fs/fat/fat.c | 16 ++++++++++------
fs/fat/fat_write.c | 4 ++--
include/fat.h | 6 +++++-
3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index c951d84f57..65873a2c2a 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -29,11 +29,13 @@ static const int vfat_enabled = 0;
#endif

/*
- * Convert a string to lowercase.
+ * Convert a string to lowercase. Converts at most 'len' characters,
+ * 'len' may be larger than the length of 'str' if 'str' is NULL
+ * terminated.
*/
-static void downcase(char *str)
+static void downcase(char *str, size_t len)
{
- while (*str != '\0') {
+ while (*str != '\0' && len--) {
*str = tolower(*str);
str++;
}
@@ -131,10 +133,13 @@ static void get_name(dir_entry *dirent, char *s_name)
ptr = s_name;
while (*ptr && *ptr != ' ')
ptr++;
+ if (dirent->lcase & CASE_LOWER_BASE)
+ downcase(s_name, (unsigned)(ptr - s_name));
if (dirent->ext[0] && dirent->ext[0] != ' ') {
- *ptr = '.';
- ptr++;
+ *ptr++ = '.';
memcpy(ptr, dirent->ext, 3);
+ if (dirent->lcase & CASE_LOWER_EXT)
+ downcase(ptr, 3);
ptr[3] = '\0';
while (*ptr && *ptr != ' ')
ptr++;
@@ -144,7 +149,6 @@ static void get_name(dir_entry *dirent, char *s_name)
*s_name = '\0';
else if (*s_name == aRING)
*s_name = DELETED_FLAG;
- downcase(s_name);
}

static int flush_dirty_fat_buffer(fsdata *mydata);
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index 4ca024c208..d0468baf8f 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -345,7 +345,7 @@ get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
*l_name = '\0';
else if (*l_name == aRING)
*l_name = DELETED_FLAG;
- downcase(l_name);
+ downcase(l_name, INT_MAX);

/* Return the real directory entry */
*retdent = realdent;
@@ -981,7 +981,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size,

memcpy(l_filename, filename, name_len);
l_filename[name_len] = 0; /* terminate the string */
- downcase(l_filename);
+ downcase(l_filename, INT_MAX);

startsect = mydata->rootdir_sect;
retdent = find_directory_entry(mydata, startsect,
diff --git a/include/fat.h b/include/fat.h
index 83cd90017e..0f58939124 100644
--- a/include/fat.h
+++ b/include/fat.h
@@ -128,10 +128,14 @@ typedef struct volume_info
/* Boot sign comes last, 2 bytes */
} volume_info;

+/* see dir_entry::lcase: */
+#define CASE_LOWER_BASE 8 /* base (name) is lower case */
+#define CASE_LOWER_EXT 16 /* extension is lower case */
+
typedef struct dir_entry {
char name[8],ext[3]; /* Name and extension */
__u8 attr; /* Attribute bits */
- __u8 lcase; /* Case for base and extension */
+ __u8 lcase; /* Case for name and ext (CASE_LOWER_x) */
__u8 ctime_ms; /* Creation time, milliseconds */
__u16 ctime; /* Creation time */
__u16 cdate; /* Creation date */
--
2.13.5