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[Qemu-devel] [PULL 19/33] s390x/3270: handle writes of arbitrary length
From: |
Cornelia Huck |
Subject: |
[Qemu-devel] [PULL 19/33] s390x/3270: handle writes of arbitrary length |
Date: |
Fri, 6 Oct 2017 11:59:42 +0200 |
From: Halil Pasic <address@hidden>
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 <address@hidden>
Acked-by: Christian Borntraeger <address@hidden>
Reviewed-by: Dong Jia Shi <address@hidden>
Reported-by: Jason J . Herne <address@hidden>
Tested-by: Jason J . Herne <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Cornelia Huck <address@hidden>
---
hw/char/terminal3270.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/hw/char/terminal3270.c b/hw/char/terminal3270.c
index c976a63cc2..a109ce5987 100644
--- a/hw/char/terminal3270.c
+++ b/hw/char/terminal3270.c
@@ -30,7 +30,6 @@ typedef struct Terminal3270 {
uint8_t inv[INPUT_BUFFER_SIZE];
uint8_t outv[OUTPUT_BUFFER_SIZE];
int in_len;
- int out_len;
bool handshake_done;
guint timer_tag;
} Terminal3270;
@@ -145,7 +144,6 @@ static void chr_event(void *opaque, int event)
/* Ensure the initial status correct, always reset them. */
t->in_len = 0;
- t->out_len = 0;
t->handshake_done = false;
if (t->timer_tag) {
g_source_remove(t->timer_tag);
@@ -231,8 +229,9 @@ static int write_payload_3270(EmulatedCcw3270Device *dev,
uint8_t cmd)
Terminal3270 *t = TERMINAL_3270(dev);
int retval = 0;
int count = ccw_dstream_avail(get_cds(t));
-
- assert(count <= (OUTPUT_BUFFER_SIZE - 3) / 2);
+ int bound = (OUTPUT_BUFFER_SIZE - 3) / 2;
+ int len = MIN(count, bound);
+ int out_len = 0;
if (!t->handshake_done) {
if (!(t->outv[0] == IAC && t->outv[1] != IAC)) {
@@ -247,16 +246,23 @@ static int write_payload_3270(EmulatedCcw3270Device *dev,
uint8_t cmd)
/* We just say we consumed all data if there's no backend. */
return count;
}
- t->outv[0] = cmd;
- ccw_dstream_read_buf(get_cds(t), &t->outv[1], count);
- t->out_len = count + 1;
- t->out_len = insert_IAC_escape_char(t->outv, t->out_len);
- t->outv[t->out_len++] = IAC;
- t->outv[t->out_len++] = IAC_EOR;
+ t->outv[out_len++] = cmd;
+ do {
+ ccw_dstream_read_buf(get_cds(t), &t->outv[out_len], len);
+ count = ccw_dstream_avail(get_cds(t));
+ out_len += len;
- retval = qemu_chr_fe_write_all(&t->chr, t->outv, t->out_len);
- return (retval <= 0) ? 0 : (retval - 3);
+ out_len = insert_IAC_escape_char(t->outv, out_len);
+ if (!count) {
+ t->outv[out_len++] = IAC;
+ t->outv[out_len++] = IAC_EOR;
+ }
+ retval = qemu_chr_fe_write_all(&t->chr, t->outv, out_len);
+ len = MIN(count, bound);
+ out_len = 0;
+ } while (len && retval >= 0);
+ return (retval <= 0) ? 0 : get_cds(t)->count;
}
static Property terminal_properties[] = {
--
2.13.6
- [Qemu-devel] [PULL 10/33] s390x/css: support ccw IDA, (continued)
- [Qemu-devel] [PULL 10/33] s390x/css: support ccw IDA, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 14/33] s390x/tcg: make stora(g) use the new _real mmu, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 13/33] s390x/tcg: make lura(g) use the new _real mmu., Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 15/33] s390x/tcg: make testblock use the new _real mmu, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 12/33] s390x/tcg: add MMU for real addresses, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 16/33] s390x/tcg: make idte/ipte use the new _real mmu, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 18/33] s390x/3270: IDA support for 3270 via CcwDataStream, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 17/33] Revert "s390x/ccw: create s390 phb conditionally", Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 20/33] MAINTAINERS: use KVM s390x maintainers for kvm-stubs.c and kvm_s390x.h, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 21/33] s390x: raise CPU hotplug irq after really hotplugged, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 19/33] s390x/3270: handle writes of arbitrary length,
Cornelia Huck <=
- [Qemu-devel] [PULL 22/33] s390x/cpumodel: fix max STFL(E) bit number, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 23/33] target/s390x: get rid of next_core_id, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 24/33] s390x: introduce and use S390_MAX_CPUS, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 27/33] s390x/css: fix css migration compat handling, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 25/33] s390x/tcg: make STFL store into the lowcore, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 26/33] s390x: sort some devices into categories, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 28/33] s390/kvm: Support for get/set of extended TOD-Clock for guest, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 31/33] s390x/sclp: mark sclp-cpu-hotplug as non-usercreatable, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 29/33] s390/kvm: make TOD setting failures fatal for migration, Cornelia Huck, 2017/10/06
- [Qemu-devel] [PULL 30/33] s390x/sclp: Mark the sclp device with user_creatable = false, Cornelia Huck, 2017/10/06