gdbstub/linux-user: support debugging over a unix socket

While debugging over TCP is fairly straightforward now we have test
cases that want to orchestrate via make and currently a parallel build
fails as two processes can't use the same listening port. While system
emulation offers a wide cornucopia of connection methods thanks to the
chardev abstraction we are a little more limited for linux user.
Thankfully the programming API for a TCP socket and a local UNIX
socket is pretty much the same once it's set up.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200430190122.4592-7-alex.bennee@linaro.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/linux-user/main.c b/linux-user/main.c
index 22578b1..2cd4432 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -51,7 +51,7 @@ char *exec_path;
 
 int singlestep;
 static const char *argv0;
-static int gdbstub_port;
+static const char *gdbstub;
 static envlist_t *envlist;
 static const char *cpu_model;
 static const char *cpu_type;
@@ -310,7 +310,7 @@ static void handle_arg_seed(const char *arg)
 
 static void handle_arg_gdb(const char *arg)
 {
-    gdbstub_port = atoi(arg);
+    gdbstub = g_strdup(arg);
 }
 
 static void handle_arg_uname(const char *arg)
@@ -861,10 +861,10 @@ int main(int argc, char **argv, char **envp)
 
     target_cpu_copy_regs(env, regs);
 
-    if (gdbstub_port) {
-        if (gdbserver_start(gdbstub_port) < 0) {
-            fprintf(stderr, "qemu: could not open gdbserver on port %d\n",
-                    gdbstub_port);
+    if (gdbstub) {
+        if (gdbserver_start(gdbstub) < 0) {
+            fprintf(stderr, "qemu: could not open gdbserver on %s\n",
+                    gdbstub);
             exit(EXIT_FAILURE);
         }
         gdb_handlesig(cpu, 0);