scm: Move scm_fdset structure into include/common

Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/include/common/scm.h b/include/common/scm.h
new file mode 100644
index 000000000..e68aa2da6
--- /dev/null
+++ b/include/common/scm.h
@@ -0,0 +1,44 @@
+#ifndef __COMMON_SCM_H__
+#define __COMMON_SCM_H__
+
+#include <stdint.h>
+
+/*
+ * Because of kernel doing kmalloc for user data passed
+ * in SCM messages, and there is kernel's SCM_MAX_FD as a limit
+ * for descriptors passed at once we're trying to reduce
+ * the pressue on kernel memory manager and use predefined
+ * known to work well size of the message buffer.
+ */
+#define CR_SCM_MSG_SIZE		(1024)
+#define CR_SCM_MAX_FD		(252)
+
+#ifdef SCM_FDSET_HAS_OPTS
+struct fd_opts {
+	char flags;
+	struct {
+		uint32_t uid;
+		uint32_t euid;
+		uint32_t signum;
+		uint32_t pid_type;
+		uint32_t pid;
+	} fown;
+};
+#endif
+
+struct scm_fdset {
+	struct msghdr	hdr;
+	struct iovec	iov;
+	char		msg_buf[CR_SCM_MSG_SIZE];
+#ifdef SCM_FDSET_HAS_OPTS
+	struct fd_opts	opts[CR_SCM_MAX_FD];
+#else
+	char		dummy;
+#endif
+};
+
+#ifndef F_GETOWNER_UIDS
+#define F_GETOWNER_UIDS	17
+#endif
+
+#endif