s390x/3270: handle writes of arbitrary length
The problem is, that the current implementation places unrealistic and arbitrary constraints on the length of writes to the device (that is the outbound requests), by asserting ccw.count being such that that even the worst case escaped payload will fit an more or less arbitrary sized buffer. Actually on protocol level there is nothing to justify such a limitation. Another strange thing is the return value which more or less reflects the size (written) after escaping instead of before escaping. This is strange, because this return value is used to calculate SCSW.count. Let us teach 3270 how to deal with arbitrary long writes. Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Reported-by: Jason J . Herne <jjherne@linux.vnet.ibm.com> Tested-by: Jason J . Herne <jjherne@linux.vnet.ibm.com> Message-Id: <20170920172314.102710-3-pasic@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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@ -30,7 +30,6 @@ typedef struct Terminal3270 {
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uint8_t inv[INPUT_BUFFER_SIZE];
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uint8_t inv[INPUT_BUFFER_SIZE];
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uint8_t outv[OUTPUT_BUFFER_SIZE];
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uint8_t outv[OUTPUT_BUFFER_SIZE];
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int in_len;
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int in_len;
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int out_len;
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bool handshake_done;
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bool handshake_done;
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guint timer_tag;
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guint timer_tag;
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} Terminal3270;
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} Terminal3270;
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@ -145,7 +144,6 @@ static void chr_event(void *opaque, int event)
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/* Ensure the initial status correct, always reset them. */
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/* Ensure the initial status correct, always reset them. */
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t->in_len = 0;
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t->in_len = 0;
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t->out_len = 0;
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t->handshake_done = false;
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t->handshake_done = false;
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if (t->timer_tag) {
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if (t->timer_tag) {
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g_source_remove(t->timer_tag);
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g_source_remove(t->timer_tag);
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@ -231,8 +229,9 @@ static int write_payload_3270(EmulatedCcw3270Device *dev, uint8_t cmd)
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Terminal3270 *t = TERMINAL_3270(dev);
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Terminal3270 *t = TERMINAL_3270(dev);
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int retval = 0;
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int retval = 0;
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int count = ccw_dstream_avail(get_cds(t));
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int count = ccw_dstream_avail(get_cds(t));
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int bound = (OUTPUT_BUFFER_SIZE - 3) / 2;
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assert(count <= (OUTPUT_BUFFER_SIZE - 3) / 2);
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int len = MIN(count, bound);
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int out_len = 0;
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if (!t->handshake_done) {
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if (!t->handshake_done) {
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if (!(t->outv[0] == IAC && t->outv[1] != IAC)) {
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if (!(t->outv[0] == IAC && t->outv[1] != IAC)) {
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@ -247,16 +246,23 @@ static int write_payload_3270(EmulatedCcw3270Device *dev, uint8_t cmd)
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/* We just say we consumed all data if there's no backend. */
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/* We just say we consumed all data if there's no backend. */
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return count;
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return count;
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}
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}
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t->outv[0] = cmd;
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ccw_dstream_read_buf(get_cds(t), &t->outv[1], count);
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t->out_len = count + 1;
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t->out_len = insert_IAC_escape_char(t->outv, t->out_len);
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t->outv[out_len++] = cmd;
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t->outv[t->out_len++] = IAC;
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do {
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t->outv[t->out_len++] = IAC_EOR;
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ccw_dstream_read_buf(get_cds(t), &t->outv[out_len], len);
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count = ccw_dstream_avail(get_cds(t));
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out_len += len;
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retval = qemu_chr_fe_write_all(&t->chr, t->outv, t->out_len);
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out_len = insert_IAC_escape_char(t->outv, out_len);
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return (retval <= 0) ? 0 : (retval - 3);
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if (!count) {
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t->outv[out_len++] = IAC;
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t->outv[out_len++] = IAC_EOR;
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}
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retval = qemu_chr_fe_write_all(&t->chr, t->outv, out_len);
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len = MIN(count, bound);
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out_len = 0;
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} while (len && retval >= 0);
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return (retval <= 0) ? 0 : get_cds(t)->count;
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}
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}
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static Property terminal_properties[] = {
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static Property terminal_properties[] = {
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