qtest: Add function to send QMP commands

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>

tests/libqtest.c

@@ -36,6 +36,7 @@ QTestState *global_qtest;
 struct QTestState
 {
     int fd;
+    int qmp_fd;
     bool irq_level[MAX_IRQ];
     GString *rx;
     gchar *pid_file;
@@ -45,48 +46,76 @@ struct QTestState
     g_assert_cmpint(ret, !=, -1); \
 } while (0)
 
+static int init_socket(const char *socket_path)
+{
+    struct sockaddr_un addr;
+    int sock;
+    int ret;
+
+    sock = socket(PF_UNIX, SOCK_STREAM, 0);
+    g_assert_no_errno(sock);
+
+    addr.sun_family = AF_UNIX;
+    snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", socket_path);
+    qemu_set_cloexec(sock);
+
+    do {
+        ret = bind(sock, (struct sockaddr *)&addr, sizeof(addr));
+    } while (ret == -1 && errno == EINTR);
+    g_assert_no_errno(ret);
+    listen(sock, 1);
+
+    return sock;
+}
+
+static int socket_accept(int sock)
+{
+    struct sockaddr_un addr;
+    socklen_t addrlen;
+    int ret;
+
+    do {
+        ret = accept(sock, (struct sockaddr *)&addr, &addrlen);
+    } while (ret == -1 && errno == EINTR);
+    g_assert_no_errno(ret);
+    close(sock);
+
+    return ret;
+}
+
 QTestState *qtest_init(const char *extra_args)
 {
     QTestState *s;
-    struct sockaddr_un addr;
-    int sock, ret, i;
+    int sock, qmpsock, ret, i;
     gchar *socket_path;
+    gchar *qmp_socket_path;
     gchar *pid_file;
     gchar *command;
     const char *qemu_binary;
     pid_t pid;
-    socklen_t addrlen;
 
     qemu_binary = getenv("QTEST_QEMU_BINARY");
     g_assert(qemu_binary != NULL);
 
     socket_path = g_strdup_printf("/tmp/qtest-%d.sock", getpid());
+    qmp_socket_path = g_strdup_printf("/tmp/qtest-%d.qmp", getpid());
     pid_file = g_strdup_printf("/tmp/qtest-%d.pid", getpid());
 
     s = g_malloc(sizeof(*s));
 
-    sock = socket(PF_UNIX, SOCK_STREAM, 0);
-    g_assert_no_errno(sock);
-
-    addr.sun_family = AF_UNIX;
-    snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", socket_path);
-    qemu_set_cloexec(sock);
-
-    do {
-        ret = bind(sock, (struct sockaddr *)&addr, sizeof(addr));
-    } while (ret == -1 && errno == EINTR);
-    g_assert_no_errno(ret);
-    listen(sock, 1);
+    sock = init_socket(socket_path);
+    qmpsock = init_socket(qmp_socket_path);
 
     pid = fork();
     if (pid == 0) {
         command = g_strdup_printf("%s "
                                   "-qtest unix:%s,nowait "
                                   "-qtest-log /dev/null "
+                                  "-qmp unix:%s,nowait "
                                   "-pidfile %s "
                                   "-machine accel=qtest "
                                   "%s", qemu_binary, socket_path,
-                                  pid_file,
+                                  qmp_socket_path, pid_file,
                                   extra_args ?: "");
 
         ret = system(command);
@@ -94,13 +123,9 @@ QTestState *qtest_init(const char *extra_args)
         g_free(command);
     }
 
-    do {
-        ret = accept(sock, (struct sockaddr *)&addr, &addrlen);
-    } while (ret == -1 && errno == EINTR);
-    g_assert_no_errno(ret);
-    close(sock);
+    s->fd = socket_accept(sock);
+    s->qmp_fd = socket_accept(qmpsock);
 
-    s->fd = ret;
     s->rx = g_string_new("");
     s->pid_file = pid_file;
     for (i = 0; i < MAX_IRQ; i++) {
@@ -108,6 +133,11 @@ QTestState *qtest_init(const char *extra_args)
     }
 
     g_free(socket_path);
+    g_free(qmp_socket_path);
+
+    /* Read the QMP greeting and then do the handshake */
+    qtest_qmp(s, "");
+    qtest_qmp(s, "{ 'execute': 'qmp_capabilities' }");
 
     return s;
 }
@@ -131,22 +161,19 @@ void qtest_quit(QTestState *s)
     }
 }
 
-static void GCC_FMT_ATTR(2, 3) qtest_sendf(QTestState *s, const char *fmt, ...)
+static void socket_sendf(int fd, const char *fmt, va_list ap)
 {
-    va_list ap;
     gchar *str;
     size_t size, offset;
 
-    va_start(ap, fmt);
     str = g_strdup_vprintf(fmt, ap);
-    va_end(ap);
     size = strlen(str);
 
     offset = 0;
     while (offset < size) {
         ssize_t len;
 
-        len = write(s->fd, str + offset, size - offset);
+        len = write(fd, str + offset, size - offset);
         if (len == -1 && errno == EINTR) {
             continue;
         }
@@ -158,6 +185,15 @@ static void GCC_FMT_ATTR(2, 3) qtest_sendf(QTestState *s, const char *fmt, ...)
     }
 }
 
+static void GCC_FMT_ATTR(2, 3) qtest_sendf(QTestState *s, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    socket_sendf(s->fd, fmt, ap);
+    va_end(ap);
+}
+
 static GString *qtest_recv_line(QTestState *s)
 {
     GString *line;
@@ -233,6 +269,39 @@ redo:
     return words;
 }
 
+void qtest_qmp(QTestState *s, const char *fmt, ...)
+{
+    va_list ap;
+    bool has_reply = false;
+    int nesting = 0;
+
+    /* Send QMP request */
+    va_start(ap, fmt);
+    socket_sendf(s->qmp_fd, fmt, ap);
+    va_end(ap);
+
+    /* Receive reply */
+    while (!has_reply || nesting > 0) {
+        ssize_t len;
+        char c;
+
+        len = read(s->qmp_fd, &c, 1);
+        if (len == -1 && errno == EINTR) {
+            continue;
+        }
+
+        switch (c) {
+        case '{':
+            nesting++;
+            has_reply = true;
+            break;
+        case '}':
+            nesting--;
+            break;
+        }
+    }
+}
+
 const char *qtest_get_arch(void)
 {
     const char *qemu = getenv("QTEST_QEMU_BINARY");

tests/libqtest.h

@@ -37,6 +37,15 @@ QTestState *qtest_init(const char *extra_args);
  */
 void qtest_quit(QTestState *s);
 
+/**
+ * qtest_qmp:
+ * @s: QTestState instance to operate on.
+ * @fmt...: QMP message to send to qemu
+ *
+ * Sends a QMP message to QEMU
+ */
+void qtest_qmp(QTestState *s, const char *fmt, ...);
+
 /**
  * qtest_get_irq:
  * @s: QTestState instance to operate on.
@@ -206,6 +215,14 @@ void qtest_add_func(const char *str, void (*fn));
     global_qtest = qtest_init((args)) \
         )
 
+/**
+ * qmp:
+ * @fmt...: QMP message to send to qemu
+ *
+ * Sends a QMP message to QEMU
+ */
+#define qmp(fmt, ...) qtest_qmp(global_qtest, fmt, ## __VA_ARGS__)
+
 /**
  * get_irq:
  * @num: Interrupt to observe.