This may be a bit too much to avoid an snprintf and the slightly dodgy
assign to a const variable. But hopefully not.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v2
  - fix checkpatch warning
---
 gdbstub/softmmu.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/gdbstub/softmmu.c b/gdbstub/softmmu.c
index 99d994e6bf..f509b7285d 100644
--- a/gdbstub/softmmu.c
+++ b/gdbstub/softmmu.c
@@ -332,11 +332,9 @@ static void create_processes(GDBState *s)
 
 int gdbserver_start(const char *device)
 {
-    trace_gdbstub_op_start(device);
-
-    char gdbstub_device_name[128];
     Chardev *chr = NULL;
     Chardev *mon_chr;
+    g_autoptr(GString) cs = g_string_new(device);
 
     if (!first_cpu) {
         error_report("gdbstub: meaningless to attach gdb to a "
@@ -350,15 +348,16 @@ int gdbserver_start(const char *device)
         return -1;
     }
 
-    if (!device) {
+    if (cs->len == 0) {
         return -1;
     }
-    if (strcmp(device, "none") != 0) {
-        if (strstart(device, "tcp:", NULL)) {
+
+    trace_gdbstub_op_start(cs->str);
+
+    if (g_strcmp0(cs->str, "none") != 0) {
+        if (g_str_has_prefix(cs->str, "tcp:")) {
             /* enforce required TCP attributes */
-            snprintf(gdbstub_device_name, sizeof(gdbstub_device_name),
-                     "%s,wait=off,nodelay=on,server=on", device);
-            device = gdbstub_device_name;
+            g_string_append_printf(cs, ",wait=off,nodelay=on,server=on");
         }
 #ifndef _WIN32
         else if (strcmp(device, "stdio") == 0) {
@@ -373,7 +372,7 @@ int gdbserver_start(const char *device)
          * FIXME: it's a bit weird to allow using a mux chardev here
          * and implicitly setup a monitor. We may want to break this.
          */
-        chr = qemu_chr_new_noreplay("gdb", device, true, NULL);
+        chr = qemu_chr_new_noreplay("gdb", cs->str, true, NULL);
         if (!chr) {
             return -1;
         }
-- 
2.39.2