hmp: make memchar-read escape ASCII control chars except \n and \t
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 66ec716..4c100d7 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -869,6 +869,8 @@
@findex ringbuf_read
Read and print up to @var{size} bytes from ring buffer character
device @var{device}.
+Certain non-printable characters are printed \uXXXX, where XXXX is the
+character code in hexadecimal. Character \ is printed \\.
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.
diff --git a/hmp.c b/hmp.c
index cbd5727..420d48b 100644
--- a/hmp.c
+++ b/hmp.c
@@ -679,6 +679,7 @@
const char *chardev = qdict_get_str(qdict, "device");
char *data;
Error *errp = NULL;
+ int i;
data = qmp_ringbuf_read(chardev, size, false, 0, &errp);
if (errp) {
@@ -687,7 +688,19 @@
return;
}
- monitor_printf(mon, "%s\n", data);
+ for (i = 0; data[i]; i++) {
+ unsigned char ch = data[i];
+
+ if (ch == '\\') {
+ monitor_printf(mon, "\\\\");
+ } else if ((ch < 0x20 && ch != '\n' && ch != '\t') || ch == 0x7F) {
+ monitor_printf(mon, "\\u%04X", ch);
+ } else {
+ monitor_printf(mon, "%c", ch);
+ }
+
+ }
+ monitor_printf(mon, "\n");
g_free(data);
}
