[Qemu-devel] [RFC PATCH 04/56] char: Make ringbuf-read size unsigned in QAPI/QMP

[Markus Armbruster <armbru@redhat.com>]

Sizes should use QAPI type 'size' (uint64_t).  ringbuf-read parameter
@size is 'int' (int64_t).  qmp_ringbuf_read() rejects negative values,
then implicitly converts to size_t.

Change the parameter to 'size' and drop the check for negative values.

ringbuf-read now accepts size values between 2^63 and 2^64-1.  It
accepts negative values as before, because that's how the QObject
input visitor works for backward compatibility.

The HMP command's size parameter remains uint32_t, as HMP args_type
strings can't do uint64_t byte counts: 'l' is signed, and 'o'
multiplies by 2^20.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 chardev/char-ringbuf.c | 11 +++--------
 qapi-schema.json       |  2 +-
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/chardev/char-ringbuf.c b/chardev/char-ringbuf.c
index df52b04..a9205ea 100644
--- a/chardev/char-ringbuf.c
+++ b/chardev/char-ringbuf.c
@@ -65,10 +65,10 @@ static int ringbuf_chr_write(Chardev *chr, const uint8_t *buf, int len)
     return len;
 }
 
-static int ringbuf_chr_read(Chardev *chr, uint8_t *buf, int len)
+static int ringbuf_chr_read(Chardev *chr, uint8_t *buf, size_t len)
 {
     RingBufChardev *d = RINGBUF_CHARDEV(chr);
-    int i;
+    size_t i;
 
     qemu_mutex_lock(&chr->chr_write_lock);
     for (i = 0; i < len && d->cons != d->prod; i++) {
@@ -151,7 +151,7 @@ void qmp_ringbuf_write(const char *device, const char *data,
     }
 }
 
-char *qmp_ringbuf_read(const char *device, int64_t size,
+char *qmp_ringbuf_read(const char *device, uint64_t size,
                        bool has_format, enum DataFormat format,
                        Error **errp)
 {
@@ -171,11 +171,6 @@ char *qmp_ringbuf_read(const char *device, int64_t size,
         return NULL;
     }
 
-    if (size <= 0) {
-        error_setg(errp, "size must be greater than zero");
-        return NULL;
-    }
-
     count = ringbuf_count(chr);
     size = size > count ? count : size;
     read_data = g_malloc(size + 1);
diff --git a/qapi-schema.json b/qapi-schema.json
index febe70e..18ec301 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -543,7 +543,7 @@
 #
 ##
 { 'command': 'ringbuf-read',
-  'data': {'device': 'str', 'size': 'int', '*format': 'DataFormat'},
+  'data': {'device': 'str', 'size': 'size', '*format': 'DataFormat'},
   'returns': 'str' }
 
 ##
-- 
2.7.5