mq: add x32-specific implementations to work around mismatched kernel ABI

the kernel mq_attr structure has 8 64-bit longs instead of 8 32-bit
longs.

it's not clear that this is the nicest way to implement the fix, but
the concept (translation) is right, and the details can be changed
later if desired.

2 files changed, 36 insertions, 0 deletions

diff --git a/src/mq/x32/mq_open.c b/src/mq/x32/mq_open.c
new file mode 100644
index 00000000..23481959
--- /dev/null
+++ b/src/mq/x32/mq_open.c
@@ -0,0 +1,22 @@
+#include <mqueue.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include "syscall.h"
+
+mqd_t mq_open(const char *name, int flags, ...)
+{
+	mode_t mode = 0;
+	struct mq_attr *attr = 0;
+	long long attrbuf[8];
+	if (*name == '/') name++;
+	if (flags & O_CREAT) {
+		va_list ap;
+		va_start(ap, flags);
+		mode = va_arg(ap, mode_t);
+		attr = va_arg(ap, struct mq_attr *);
+		if (attr) for (int i=0; i<8; i++)
+			attrbuf[i] = *(long *)((char *)attr + i*sizeof(long));
+		va_end(ap);
+	}
+	return syscall(SYS_mq_open, name, flags, mode, attr?attrbuf:0);
+}
diff --git a/src/mq/x32/mq_setattr.c b/src/mq/x32/mq_setattr.c
new file mode 100644
index 00000000..0c631175
--- /dev/null
+++ b/src/mq/x32/mq_setattr.c
@@ -0,0 +1,14 @@
+#include <mqueue.h>
+#include "syscall.h"
+
+int mq_setattr(mqd_t mqd, const struct mq_attr *restrict new, struct mq_attr *restrict old)
+{
+	long long attr[8];
+	if (new) for (int i=0; i<8; i++)
+		attr[i] = *(long *)((char *)new + i*sizeof(long));
+	int ret = __syscall(SYS_mq_getsetattr, mqd, new?attr:0, old?attr:0);
+	if (ret < 0) return __syscall_ret(ret);
+	if (old) for (int i=0; i<8; i++)
+		*(long *)((char *)old + i*sizeof(long)) = attr[i];
+	return 0;
+}