chardev: Add 'help' option to print all available chardev backend types
Signed-off-by: Lin Ma <lma@suse.com>
Message-Id: <20160816171352.17021-1-lma@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/qemu-char.c b/qemu-char.c
index 5f82ebb..cf6a27a 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -39,6 +39,7 @@
#include "io/channel-file.h"
#include "io/channel-tls.h"
#include "sysemu/replay.h"
+#include "qemu/help_option.h"
#include <zlib.h>
@@ -3879,16 +3880,26 @@
const char *id = qemu_opts_id(opts);
char *bid = NULL;
- if (id == NULL) {
- error_setg(errp, "chardev: no id specified");
- goto err;
- }
-
if (qemu_opt_get(opts, "backend") == NULL) {
error_setg(errp, "chardev: \"%s\" missing backend",
qemu_opts_id(opts));
goto err;
}
+
+ if (is_help_option(qemu_opt_get(opts, "backend"))) {
+ fprintf(stderr, "Available chardev backend types:\n");
+ for (i = backends; i; i = i->next) {
+ cd = i->data;
+ fprintf(stderr, "%s\n", cd->name);
+ }
+ exit(!is_help_option(qemu_opt_get(opts, "backend")));
+ }
+
+ if (id == NULL) {
+ error_setg(errp, "chardev: no id specified");
+ goto err;
+ }
+
for (i = backends; i; i = i->next) {
cd = i->data;
diff --git a/qemu-options.hx b/qemu-options.hx
index 5209626..4927939 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2152,6 +2152,7 @@
ETEXI
DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
+ "-chardev help\n"
"-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
"-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
" [,server][,nowait][,telnet][,reconnect=seconds][,mux=on|off]\n"
@@ -2217,6 +2218,8 @@
@option{spiceport}.
The specific backend will determine the applicable options.
+Use "-chardev help" to print all available chardev backend types.
+
All devices must have an id, which can be any string up to 127 characters long.
It is used to uniquely identify this device in other command line directives.
