[Qemu-devel] [PATCH v2] qtest: Don't segfault with invalid -qtest option

[Fam Zheng <famz@redhat.com>]

This prints an error message, instead of core dump, when "-qtest"
option value is invalid, e.g.:

    $ ./x86_64-softmmu/qemu-system-x86_64 -qtest unknown
        qemu-system-x86_64: Failed to initialize device for qtest:
        "unknown"

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 include/sysemu/qtest.h | 3 ++-
 qtest.c                | 8 +++++++-
 vl.c                   | 8 +++++++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/sysemu/qtest.h b/include/sysemu/qtest.h
index 112a661..2de61c6 100644
--- a/include/sysemu/qtest.h
+++ b/include/sysemu/qtest.h
@@ -15,6 +15,7 @@
 #define QTEST_H
 
 #include "qemu-common.h"
+#include "qapi/error.h"
 
 extern bool qtest_allowed;
 
@@ -24,7 +25,7 @@ static inline bool qtest_enabled(void)
 }
 
 int qtest_init_accel(void);
-void qtest_init(const char *qtest_chrdev, const char *qtest_log);
+void qtest_init(const char *qtest_chrdev, const char *qtest_log, Error **errp);
 
 static inline int qtest_available(void)
 {
diff --git a/qtest.c b/qtest.c
index dcf1301..a4ad407 100644
--- a/qtest.c
+++ b/qtest.c
@@ -507,12 +507,18 @@ int qtest_init_accel(void)
     return 0;
 }
 
-void qtest_init(const char *qtest_chrdev, const char *qtest_log)
+void qtest_init(const char *qtest_chrdev, const char *qtest_log, Error **errp)
 {
     CharDriverState *chr;
 
     chr = qemu_chr_new("qtest", qtest_chrdev, NULL);
 
+    if (chr == NULL) {
+        error_setg(errp, "Failed to initialize device for qtest: \"%s\"",
+                   qtest_chrdev);
+        return;
+    }
+
     qemu_chr_add_handlers(chr, qtest_can_read, qtest_read, qtest_event, chr);
     qemu_chr_fe_set_echo(chr, true);
 
diff --git a/vl.c b/vl.c
index e2e576c..bee455d 100644
--- a/vl.c
+++ b/vl.c
@@ -4079,7 +4079,13 @@ int main(int argc, char **argv, char **envp)
     configure_accelerator();
 
     if (qtest_chrdev) {
-        qtest_init(qtest_chrdev, qtest_log);
+        Error *local_err = NULL;
+        qtest_init(qtest_chrdev, qtest_log, &local_err);
+        if (error_is_set(&local_err)) {
+            error_report("%s", error_get_pretty(local_err));
+            error_free(local_err);
+            exit(1);
+        }
     }
 
     machine_opts = qemu_get_machine_opts();
-- 
1.8.5.4