1 files changed, 128 insertions, 0 deletions
diff --git a/compatfd.c b/compatfd.c
new file mode 100644
index 0000000000..46b0ae7ab7
--- /dev/null
+++ b/compatfd.c
@@ -0,0 +1,128 @@
+/*
+ * signalfd/eventfd compatibility
+ *
+ * Copyright IBM, Corp. 2008
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu-common.h"
+#include "compatfd.h"
+
+#include <sys/syscall.h>
+#include <pthread.h>
+
+struct sigfd_compat_info
+{
+    sigset_t mask;
+    int fd;
+};
+
+static void *sigwait_compat(void *opaque)
+{
+    struct sigfd_compat_info *info = opaque;
+    int err;
+    sigset_t all;
+
+    sigfillset(&all);
+    sigprocmask(SIG_BLOCK, &all, NULL);
+
+    do {
+	siginfo_t siginfo;
+
+	err = sigwaitinfo(&info->mask, &siginfo);
+	if (err == -1 && errno == EINTR) {
+            err = 0;
+            continue;
+        }
+
+	if (err > 0) {
+	    char buffer[128];
+	    size_t offset = 0;
+
+	    memcpy(buffer, &err, sizeof(err));
+	    while (offset < sizeof(buffer)) {
+		ssize_t len;
+
+		len = write(info->fd, buffer + offset,
+			    sizeof(buffer) - offset);
+		if (len == -1 && errno == EINTR)
+		    continue;
+
+		if (len <= 0) {
+		    err = -1;
+		    break;
+		}
+
+		offset += len;
+	    }
+	}
+    } while (err >= 0);
+
+    return NULL;
+}
+
+static int qemu_signalfd_compat(const sigset_t *mask)
+{
+    pthread_attr_t attr;
+    pthread_t tid;
+    struct sigfd_compat_info *info;
+    int fds[2];
+
+    info = malloc(sizeof(*info));
+    if (info == NULL) {
+	errno = ENOMEM;
+	return -1;
+    }
+
+    if (pipe(fds) == -1) {
+	free(info);
+	return -1;
+    }
+
+    memcpy(&info->mask, mask, sizeof(*mask));
+    info->fd = fds[1];
+
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+    pthread_create(&tid, &attr, sigwait_compat, info);
+
+    pthread_attr_destroy(&attr);
+
+    return fds[0];
+}
+
+int qemu_signalfd(const sigset_t *mask)
+{
+#if defined(SYS_signalfd)
+    int ret;
+
+    ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
+    if (!(ret == -1 && errno == ENOSYS))
+	return ret;
+#endif
+
+    return qemu_signalfd_compat(mask);
+}
+
+int qemu_eventfd(int *fds)
+{
+#if defined(SYS_eventfd)
+    int ret;
+
+    ret = syscall(SYS_eventfd, 0);
+    if (ret >= 0) {
+	fds[0] = fds[1] = ret;
+	return 0;
+    } else if (!(ret == -1 && errno == ENOSYS))
+	return ret;
+#endif
+
+    return pipe(fds);
+}