Introduce SYSCALL_INIT_HELPER and SYSCALL32_INIT_HELPER macros and

neccessary support functions to allow registering dynamically loaded
syscalls from the MOD_LOAD handlers. Helpers handle registration
failures semi-automatically.

Reviewed by:	jhb
MFC after:	2 weeks

1 files changed, 30 insertions, 0 deletions

diff --git a/sys/kern/kern_syscalls.c b/sys/kern/kern_syscalls.c
index 077aedc..9cb7b68 100644
--- a/sys/kern/kern_syscalls.c
+++ b/sys/kern/kern_syscalls.c
@@ -135,3 +135,33 @@ syscall_module_handler(struct module *mod, int what, void *arg)
 	else
 		return (0);
 }
+
+int
+syscall_helper_register(struct syscall_helper_data *sd)
+{
+	struct syscall_helper_data *sd1;
+	int error;
+
+	for (sd1 = sd; sd1->syscall_no != NO_SYSCALL; sd1++) {
+		error = syscall_register(&sd1->syscall_no, &sd1->new_sysent,
+		    &sd1->old_sysent);
+		if (error != 0) {
+			syscall_helper_unregister(sd);
+			return (error);
+		}
+		sd1->registered = 1;
+	}
+	return (0);
+}
+
+int
+syscall_helper_unregister(struct syscall_helper_data *sd)
+{
+	struct syscall_helper_data *sd1;
+
+	for (sd1 = sd; sd1->registered != 0; sd1++) {
+		syscall_deregister(&sd1->syscall_no, &sd1->old_sysent);
+		sd1->registered = 0;
+	}
+	return (0);
+}