[PATCH v3] libqtest: refuse QTEST_QEMU_BINARY=qemu-kvm

[Stefan Hajnoczi <stefanha@redhat.com>]

Some downstreams rename the QEMU binary to "qemu-kvm". This breaks
qtest_get_arch(), which attempts to parse the target architecture from
the QTEST_QEMU_BINARY environment variable.

Print an error instead of returning the architecture "kvm". Things fail
in weird ways when the architecture string is bogus.

Arguably qtests should always be run in a build directory instead of
against an installed QEMU. In any case, printing a clear error when this
happens is helpful.

Since this is an error that is triggered by the user and not a test
failure, use exit(1) instead of abort(). Change the existing abort()
call in qtest_get_arch() to exit(1) too for the same reason and to be
consistent.

Reported-by: Qin Wang <qinwang@rehdat.com>
Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
v3:
 * Add newline to wrap error message output at 80 columns [Thomas]
 * Drop information about working around this using a symlink [Thomas]
 * Use exit(1) instead of abort() [Thomas]

 tests/qtest/libqtest.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 71e359efcd..825b13a44c 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -907,7 +907,14 @@ const char *qtest_get_arch(void)
 
     if (!end) {
         fprintf(stderr, "Can't determine architecture from binary name.\n");
-        abort();
+        exit(1);
+    }
+
+    if (!strstr(qemu, "-system-")) {
+        fprintf(stderr, "QTEST_QEMU_BINARY must end with *-system-<arch> "
+                "where 'arch' is the target\narchitecture (x86_64, aarch64, "
+                "etc).\n");
+        exit(1);
     }
 
     return end + 1;
-- 
2.30.2