Markus Armbruster <arm...@redhat.com> writes:
> Gerd Hoffmann <kra...@redhat.com> writes:
>
>> Make utf16_to_str return an allocated string. Remove the assumtion that
>> the number of string bytes equals the number of utf16 chars (which is
>> only true for ascii chars). Instead call wcstombs twice, once to figure
>> the storage size and once for the actual conversion (as suggested by the
>> wcstombs manpage).
>>
>> Reported-by: Michael Hanselmann (hansmi.ch)
>> Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
>> ---
>> hw/usb/dev-mtp.c | 17 +++++++++++------
>> 1 file changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
>> index 00a3691bae..fbe1ace035 100644
>> --- a/hw/usb/dev-mtp.c
>> +++ b/hw/usb/dev-mtp.c
>> @@ -1593,17 +1593,22 @@ static void usb_mtp_cancel_packet(USBDevice *dev,
>> USBPacket *p)
>> fprintf(stderr, "%s\n", __func__);
>> }
>>
>> -static void utf16_to_str(uint8_t len, uint16_t *arr, char *name)
>> +static char *utf16_to_str(uint8_t len, uint16_t *arr)
>> {
>> - int count;
>> - wchar_t *wstr = g_new0(wchar_t, len);
>> + wchar_t *wstr = g_new0(wchar_t, len + 1);
>> + int count, dlen;
>> + char *dest;
>>
>> for (count = 0; count < len; count++) {
>> wstr[count] = (wchar_t)arr[count];
>> }
>> + wstr[count] = 0;
>>
>> - wcstombs(name, wstr, len);
>> + dlen = wcstombs(NULL, wstr, 0) + 1;
>> + dest = g_malloc(dlen);
>> + wcstombs(dest, wstr, dlen);
>> g_free(wstr);
>> + return dest;
>> }
>
> Preexisting: casting uint16_t to wchar_t is iffy for at least two
> reasons:
>
> * When wchar_t is UCS-4, things fall apart for surrogate pairs. For
> instance, the surrogate pair
>
> uint16_t arr = { 0xD834, 0xDD1E };
>
> should map to the single wchar_t 0x1D11E.
>
> * wchar_t needn't even be Unicode. It might well be on any host we care
> for, but are you *sure*?
>
> I guess g_utf16_to_utf8() would be differently wrong: it converts to
> UTF-8, but we need to convert to the current locale's multibyte string.
>
I couldn't find an existing function that I could safely reuse which was my
first
preference. I will take a look at how to make this function better, maybe,
even see what other MTP implementations are doing in this regard.
Bandan
>>
>> /* Wrapper around write, returns 0 on failure */
>> @@ -1703,7 +1708,7 @@ static void usb_mtp_write_metadata(MTPState *s)
>> {
>> MTPData *d = s->data_out;
>> ObjectInfo *dataset = (ObjectInfo *)d->data;
>> - char *filename = g_new0(char, dataset->length);
>> + char *filename;
>> MTPObject *o;
>> MTPObject *p = usb_mtp_object_lookup(s, s->dataset.parent_handle);
>> uint32_t next_handle = s->next_handle;
>> @@ -1711,7 +1716,7 @@ static void usb_mtp_write_metadata(MTPState *s)
>> assert(!s->write_pending);
>> assert(p != NULL);
>>
>> - utf16_to_str(dataset->length, dataset->filename, filename);
>> + filename = utf16_to_str(dataset->length, dataset->filename);
>>
>> o = usb_mtp_object_lookup_name(p, filename, dataset->length);
>> if (o != NULL) {
