[PATCH 4/5] hw/i2c: pmbus: block uninitialised string reads

[Titus Rwantare]

Devices models calling pmbus_send_string can't be relied upon to
send a non-zero pointer. This logs an error and doesn't segfault.

Reviewed-by: Patrick Venture <venture@google.com>
Signed-off-by: Titus Rwantare <titusr@google.com>
---
 hw/i2c/pmbus_device.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
index bb42e410b4..18e629eaac 100644
--- a/hw/i2c/pmbus_device.c
+++ b/hw/i2c/pmbus_device.c
@@ -94,6 +94,13 @@ void pmbus_send64(PMBusDevice *pmdev, uint64_t data)
 
 void pmbus_send_string(PMBusDevice *pmdev, const char *data)
 {
+    if (!data) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: %s: uninitialised read from 0x%02x\n",
+                      __func__, DEVICE(pmdev)->canonical_path, pmdev->code);
+        return;
+    }
+
     size_t len = strlen(data);
     g_assert(len + pmdev->out_buf_len < SMBUS_DATA_MAX_LEN);
     pmdev->out_buf[len + pmdev->out_buf_len] = len;
-- 
2.40.0.rc1.284.g88254d51c5-goog