Markus Armbruster <armbru@redhat.com> writes:
The __linux__ version of qemu_chr_open_pp_fd() tries to claim the parport device with a PPCLAIM ioctl(). On success, it stores the file descriptor in the chardev object, and returns success. On failure, it closes the file descriptor, and returns failure.
chardev_new() then passes the Chardev to object_unref(). This duly calls char_parallel_finalize(), which closes the file descriptor stored in the chardev object. Since qemu_chr_open_pp_fd() didn't store it, it's still zero, so this closes standard input. Ooopsie.
To demonstate, add a unit test. With the bug above unfixed, running this test closes standard input. char_hotswap_test() happens to run next. It opens a socket, duly gets file descriptor 0, and since it tests for success with > 0 instead of >= 0, it fails.
The test needs to be conditional exactly like the chardev it tests. Since the condition is rather complicated, steal the solution from the serial chardev: define HAVE_CHARDEV_PARALLEL in qemu/osdep.h. This also permits simplifying chardev/meson.build a bit.
The bug fix is easy enough: store the file descriptor, and leave closing it to char_parallel_finalize().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
[...]
diff --git a/chardev/char-parallel.c b/chardev/char-parallel.c index a5164f975a..78697d7522 100644 --- a/chardev/char-parallel.c +++ b/chardev/char-parallel.c @@ -164,13 +164,13 @@ static void qemu_chr_open_pp_fd(Chardev *chr, { ParallelChardev *drv = PARALLEL_CHARDEV(chr);
+ drv->fd = fd; + if (ioctl(fd, PPCLAIM) < 0) { error_setg_errno(errp, errno, "not a parallel port"); - close(fd); return; }
- drv->fd = fd; drv->mode = IEEE1284_MODE_COMPAT; } #endif /* __linux__ */ @@ -238,6 +238,7 @@ static void qemu_chr_open_pp_fd(Chardev *chr, } #endif
+#ifdef HAVE_CHARDEV_PARALLEL static void qmp_chardev_open_parallel(Chardev *chr, ChardevBackend *backend, bool *be_opened, @@ -306,3 +307,5 @@ static void register_types(void) }
type_init(register_types); + +#endif /* HAVE_CHARDEV_PARALLEL */ diff --git a/tests/unit/test-char.c b/tests/unit/test-char.c index 649fdf64e1..76946e6f90 100644 --- a/tests/unit/test-char.c +++ b/tests/unit/test-char.c @@ -1203,6 +1203,24 @@ static void char_serial_test(void) } #endif
+#if defined(HAVE_CHARDEV_PARALLEL) && !defined(WIN32) +static void char_parallel_test(void) +{ + QemuOpts *opts; + Chardev *chr; + + opts = qemu_opts_create(qemu_find_opts("chardev"), "parallel-id", + 1, &error_abort); + qemu_opt_set(opts, "backend", "parallel", &error_abort); + qemu_opt_set(opts, "path", "/dev/null", &error_abort); + + chr = qemu_chr_new_from_opts(opts, NULL, NULL); + g_assert_null(chr);
This is wrong. On a Linux host, qemu_chr_new_from_opts() fails, because qemu_chr_open_pp_fd()'s attempt to PPCLAIM fails. On a BSD host, it succeeds. Proposed fixup appended. Marc-André, is respinning the PR with the fixup okay, or would you prefer a v2?
+ + qemu_opts_del(opts); +} +#endif + #ifndef _WIN32 static void char_file_fifo_test(void) { @@ -1544,6 +1562,9 @@ int main(int argc, char **argv) g_test_add_func("/char/udp", char_udp_test); #if defined(HAVE_CHARDEV_SERIAL) && !defined(WIN32) g_test_add_func("/char/serial", char_serial_test); +#endif +#if defined(HAVE_CHARDEV_PARALLEL) && !defined(WIN32) + g_test_add_func("/char/parallel", char_parallel_test); #endif g_test_add_func("/char/hotswap", char_hotswap_test); g_test_add_func("/char/websocket", char_websock_test);
[...] diff --git a/tests/unit/test-char.c b/tests/unit/test-char.c index e3b783c06b..f273ce5226 100644 --- a/tests/unit/test-char.c +++ b/tests/unit/test-char.c @@ -1215,7 +1215,13 @@ static void char_parallel_test(void) qemu_opt_set(opts, "path", "/dev/null", &error_abort); chr = qemu_chr_new_from_opts(opts, NULL, NULL); +#ifdef __linux__ + /* fails to PPCLAIM, see qemu_chr_open_pp_fd() */ g_assert_null(chr); +#else + g_assert_nonnull(chr); + object_unparent(OBJECT(chr)); +#endif qemu_opts_del(opts); }