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.
>
> /* 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) {
