FAT file system's long file name support is a bit complicated and has some restrictions on its naming. We should be careful about it especially for write as it may easily end up with wrong file system.
normalize_longname() check for the rules and normalize a file name if necessary. Please note, however, that this function is yet to be extended to fully comply with the standard.
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- fs/fat/fat_write.c | 52 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 44 insertions(+), 8 deletions(-)
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 3b77557b3e..6c715a70f4 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -899,6 +899,44 @@ static dir_entry *find_directory_entry(fsdata *mydata, int startsect, return NULL; }
+static int normalize_longname(char *l_filename, const char *filename) +{ + const char *p, legal[] = "!#$%&'()-.@^`_{}~"; + char c; + int name_len; + + /* Check that the filename is valid */ + for (p = filename; p < filename + strlen(filename); p++) { + c = *p; + + if (('0' <= c) && (c <= '9')) + continue; + if (('A' <= c) && (c <= 'Z')) + continue; + if (('a' <= c) && (c <= 'z')) + continue; + if (strchr(legal, c)) + continue; + /* extended code */ + if ((0x80 <= c) && (c <= 0xff)) + continue; + + return -1; + } + + /* Normalize it */ + name_len = strlen(filename); + if (name_len >= VFAT_MAXLEN_BYTES) + /* should return an error? */ + name_len = VFAT_MAXLEN_BYTES - 1; + + memcpy(l_filename, filename, name_len); + l_filename[name_len] = 0; /* terminate the string */ + downcase(l_filename, INT_MAX); + + return 0; +} + static int do_fat_write(const char *filename, void *buffer, loff_t size, loff_t *actwrite) { @@ -910,7 +948,7 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size, fsdata datablock; fsdata *mydata = &datablock; int cursect; - int ret = -1, name_len; + int ret = -1; char l_filename[VFAT_MAXLEN_BYTES];
*actwrite = size; @@ -971,13 +1009,11 @@ static int do_fat_write(const char *filename, void *buffer, loff_t size, } dentptr = (dir_entry *) do_fat_read_at_block;
- name_len = strlen(filename); - if (name_len >= VFAT_MAXLEN_BYTES) - name_len = VFAT_MAXLEN_BYTES - 1; - - memcpy(l_filename, filename, name_len); - l_filename[name_len] = 0; /* terminate the string */ - downcase(l_filename, INT_MAX); + if (normalize_longname(l_filename, filename)) { + printf("FAT: illegal filename (%s)\n", filename); + ret = -EINVAL; + goto exit; + }
startsect = mydata->rootdir_sect; retdent = find_directory_entry(mydata, startsect,