chardev/parallel: Don't close stdin on inappropriate device
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 new unit 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().
The next commit will fix char_hotswap_test()'s test for success.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240203080228.2766159-2-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Test fixed up for BSDs, indentation fixed up, commit message improved]
diff --git a/chardev/char-parallel.c b/chardev/char-parallel.c
index a5164f9..78697d7 100644
--- a/chardev/char-parallel.c
+++ b/chardev/char-parallel.c
@@ -164,13 +164,13 @@
{
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 @@
}
#endif
+#ifdef HAVE_CHARDEV_PARALLEL
static void qmp_chardev_open_parallel(Chardev *chr,
ChardevBackend *backend,
bool *be_opened,
@@ -306,3 +307,5 @@
}
type_init(register_types);
+
+#endif /* HAVE_CHARDEV_PARALLEL */
diff --git a/chardev/meson.build b/chardev/meson.build
index c80337d..70070a8 100644
--- a/chardev/meson.build
+++ b/chardev/meson.build
@@ -21,11 +21,9 @@
else
chardev_ss.add(files(
'char-fd.c',
+ 'char-parallel.c',
'char-pty.c',
), util)
- if host_os in ['linux', 'gnu/kfreebsd', 'freebsd', 'dragonfly']
- chardev_ss.add(files('char-parallel.c'))
- endif
endif
chardev_ss = chardev_ss.apply({})
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 7d359da..c7053cd 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -508,11 +508,18 @@
#ifdef _WIN32
#define HAVE_CHARDEV_SERIAL 1
-#elif defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
+#define HAVE_CHARDEV_PARALLEL 1
+#else
+#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
|| defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
|| defined(__GLIBC__) || defined(__APPLE__)
#define HAVE_CHARDEV_SERIAL 1
#endif
+#if defined(__linux__) || defined(__FreeBSD__) \
+ || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
+#define HAVE_CHARDEV_PARALLEL 1
+#endif
+#endif
#if defined(__HAIKU__)
#define SIGIO SIGPOLL
diff --git a/tests/unit/test-char.c b/tests/unit/test-char.c
index 649fdf6..2aea49c 100644
--- a/tests/unit/test-char.c
+++ b/tests/unit/test-char.c
@@ -1203,6 +1203,30 @@
}
#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);
+#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);
+}
+#endif
+
#ifndef _WIN32
static void char_file_fifo_test(void)
{
@@ -1545,6 +1569,9 @@
#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);
