gdbstub: Allow re-instantiation (Jan Kiszka)

[ Note: depends on char closing fixes ]

Properly clean up the gdbstub when the user tries to re-open it
(possibly under a different address). Moreover, allow to shut it down
from the monitor via 'gdbserver none'.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6913 c046a42c-6fe2-441c-8c8c-71466251a162

gdbstub.c

@@ -265,6 +265,7 @@ typedef struct GDBRegisterState {
 } GDBRegisterState;
 
 enum RSState {
+    RS_INACTIVE,
     RS_IDLE,
     RS_GETLINE,
     RS_CHKSUM1,
@@ -1924,7 +1925,7 @@ static void gdb_vm_state_change(void *opaque, int running, int reason)
     int ret;
 
     if (running || (reason != EXCP_DEBUG && reason != EXCP_INTERRUPT) ||
-        s->state == RS_SYSCALL)
+        s->state == RS_INACTIVE || s->state == RS_SYSCALL)
         return;
 
     /* disable single step if it was enable */
@@ -2342,11 +2343,12 @@ int gdbserver_start(const char *port)
     char gdbstub_port_name[128];
     int port_num;
     char *p;
-    CharDriverState *chr;
+    CharDriverState *chr = NULL;
+    CharDriverState *mon_chr;
 
     if (!port || !*port)
       return -1;
-
+    if (strcmp(port, "none") != 0) {
         port_num = strtol(port, &p, 10);
         if (*p == 0) {
             /* A numeric value is interpreted as a port number.  */
@@ -2359,19 +2361,32 @@ int gdbserver_start(const char *port)
         if (!chr)
             return -1;
 
-    s = qemu_mallocz(sizeof(GDBState));
-    s->c_cpu = first_cpu;
-    s->g_cpu = first_cpu;
-    s->chr = chr;
-    gdbserver_state = s;
         qemu_chr_add_handlers(chr, gdb_chr_can_receive, gdb_chr_receive,
                               gdb_chr_event, NULL);
+    }
+
+    s = gdbserver_state;
+    if (!s) {
+        s = qemu_mallocz(sizeof(GDBState));
+        gdbserver_state = s;
+
         qemu_add_vm_change_state_handler(gdb_vm_state_change, NULL);
 
         /* Initialize a monitor terminal for gdb */
-    s->mon_chr = qemu_mallocz(sizeof(*s->mon_chr));
-    s->mon_chr->chr_write = gdb_monitor_write;
-    monitor_init(s->mon_chr, 0);
+        mon_chr = qemu_mallocz(sizeof(*mon_chr));
+        mon_chr->chr_write = gdb_monitor_write;
+        monitor_init(mon_chr, 0);
+    } else {
+        if (s->chr)
+            qemu_chr_close(s->chr);
+        mon_chr = s->mon_chr;
+        memset(s, 0, sizeof(GDBState));
+    }
+    s->c_cpu = first_cpu;
+    s->g_cpu = first_cpu;
+    s->chr = chr;
+    s->state = chr ? RS_IDLE : RS_INACTIVE;
+    s->mon_chr = mon_chr;
 
     return 0;
 }

monitor.c

@@ -577,6 +577,8 @@ static void do_gdbserver(Monitor *mon, const char *port)
     if (gdbserver_start(port) < 0) {
         monitor_printf(mon, "Could not open gdbserver socket on port '%s'\n",
                        port);
+    } else if (strcmp(port, "none") == 0) {
+        monitor_printf(mon, "Disabled gdbserver\n");
     } else {
         monitor_printf(mon, "Waiting gdb connection on port '%s'\n", port);
     }