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authorMarkus Armbruster <armbru@redhat.com>2024-02-03 09:02:25 +0100
committerMarkus Armbruster <armbru@redhat.com>2024-02-14 07:44:38 +0100
commita58c439a2d2c07ec05429d8774d75faeef4eac1e (patch)
tree38398350bc3e1c28027f093d4879d91927754d40 /include/qemu/osdep.h
parent5d1fc614413b10dd94858b07a1b2e26b1aa0296c (diff)
downloadfocaccia-qemu-a58c439a2d2c07ec05429d8774d75faeef4eac1e.tar.gz
focaccia-qemu-a58c439a2d2c07ec05429d8774d75faeef4eac1e.zip
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]
Diffstat (limited to 'include/qemu/osdep.h')
-rw-r--r--include/qemu/osdep.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 7d359dabc4..c7053cdc2b 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -508,11 +508,18 @@ void qemu_anon_ram_free(void *ptr, size_t size);
 
 #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