qemu-char: Saner naming of memchar stuff & doc fixes
New device, has never been released, so we can still improve things
without worrying about compatibility.
Naming is a mess. The code calls the device driver CirMemCharDriver,
the public API calls it "memory", "memchardev", or "memchar", and the
special commands are named like "memchar-FOO". "memory" is a
particularly unfortunate choice, because there's another character
device driver called MemoryDriver. Moreover, the device's distinctive
property is that it's a ring buffer, not that's in memory. Therefore:
* Rename CirMemCharDriver to RingBufCharDriver, and call the thing a
"ringbuf" in the API.
* Rename QMP and HMP commands from memchar-FOO to ringbuf-FOO.
* Rename device parameter from maxcapacity to size (simple words are
good for you).
* Clearly mark the parameter as optional in documentation.
* Fix error reporting so that chardev-add reports to current monitor,
not stderr.
* Replace cirmem in C identifiers by ringbuf.
* Rework documentation. Document the impact of our crappy UTF-8
handling on reading.
* QMP examples that even work.
I could split this up into multiple commits, but they'd change the
same documentation lines multiple times. Not worth it.
Signed-off-by: Markus Armbruster <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Signed-off-by: Anthony Liguori <[email protected]>
diff --git a/hmp-commands.hx b/hmp-commands.hx
index bdd48f3..66ec716 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -841,40 +841,37 @@
ETEXI
{
- .name = "memchar_write",
+ .name = "ringbuf_write",
.args_type = "device:s,data:s",
.params = "device data",
- .help = "Provide writing interface for CirMemCharDriver. Write"
- "'data' to it.",
- .mhandler.cmd = hmp_memchar_write,
+ .help = "Write to a ring buffer character device",
+ .mhandler.cmd = hmp_ringbuf_write,
},
STEXI
-@item memchar_write @var{device} @var{data}
-@findex memchar_write
-Provide writing interface for CirMemCharDriver. Write @var{data}
-to char device 'memory'.
+@item ringbuf_write @var{device} @var{data}
+@findex ringbuf_write
+Write @var{data} to ring buffer character device @var{device}.
+@var{data} must be a UTF-8 string.
ETEXI
{
- .name = "memchar_read",
+ .name = "ringbuf_read",
.args_type = "device:s,size:i",
.params = "device size",
- .help = "Provide read interface for CirMemCharDriver. Read from"
- "it and return the data with size.",
- .mhandler.cmd = hmp_memchar_read,
+ .help = "Read from a ring buffer character device",
+ .mhandler.cmd = hmp_ringbuf_read,
},
STEXI
-@item memchar_read @var{device}
-@findex memchar_read
-Provide read interface for CirMemCharDriver. Read from char device
-'memory' and return the data.
-
-@var{size} is the size of data want to read from. Refer to unencoded
-size of the raw data, would adjust to the init size of the memchar
-if the requested size is larger than it.
+@item ringbuf_read @var{device}
+@findex ringbuf_read
+Read and print up to @var{size} bytes from ring buffer character
+device @var{device}.
+Bug: can screw up when the buffer contains invalid UTF-8 sequences,
+NUL characters, after the ring buffer lost data, and when reading
+stops because the size limit is reached.
ETEXI
