Re: [Linux-streams] Re: [PATCH] Re: export of sys_call_tabl

[David Grothe <dave@gcom.com>]

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Attached is the "final" patch.  I eliminated the unregister function.  This 
is tested on stock 2.4.19 kernel.

Will someone see that it is added to the kernel source?

Thanks,
Dave

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--- arch/i386/kernel/entry.S.orig	2002-08-02 19:39:42.000000000 -0500
+++ arch/i386/kernel/entry.S	2002-10-08 15:43:08.000000000 -0500
@@ -584,8 +584,8 @@
 	.long SYMBOL_NAME(sys_capset)           /* 185 */
 	.long SYMBOL_NAME(sys_sigaltstack)
 	.long SYMBOL_NAME(sys_sendfile)
-	.long SYMBOL_NAME(sys_ni_syscall)		/* streams1 */
-	.long SYMBOL_NAME(sys_ni_syscall)		/* streams2 */
+	.long SYMBOL_NAME(sys_getpmsg)		/* streams1 */
+	.long SYMBOL_NAME(sys_putpmsg)		/* streams2 */
 	.long SYMBOL_NAME(sys_vfork)            /* 190 */
 	.long SYMBOL_NAME(sys_getrlimit)
 	.long SYMBOL_NAME(sys_mmap2)
--- kernel/ksyms.c.orig	2002-08-02 19:39:46.000000000 -0500
+++ kernel/ksyms.c	2002-10-10 11:46:54.000000000 -0500
@@ -497,6 +497,9 @@
 EXPORT_SYMBOL(seq_release);
 EXPORT_SYMBOL(seq_read);
 EXPORT_SYMBOL(seq_lseek);
+extern int register_streams_calls(int (*putpmsg) (int,void *,void *,int,int),
+				   int (*getpmsg) (int,void *,void *,int,int));
+EXPORT_SYMBOL(register_streams_calls);
 
 /* Program loader interfaces */
 EXPORT_SYMBOL(setup_arg_pages);
--- kernel/sys.c.orig	2002-08-02 19:39:46.000000000 -0500
+++ kernel/sys.c	2002-10-10 11:46:44.000000000 -0500
@@ -167,6 +167,48 @@
 	return notifier_chain_unregister(&reboot_notifier_list, nb);
 }
 
+static int (*do_putpmsg) (int, void *, void *, int, int) = NULL;
+static int (*do_getpmsg) (int, void *, void *, int, int) = NULL;
+
+static DECLARE_RWSEM(streams_call_sem) ;
+
+long asmlinkage sys_putpmsg(int fd, void *ctlptr, void *datptr, int band, int flags)
+{
+	int ret = -ENOSYS;
+	down_read(&streams_call_sem) ;	/* should return int, but doesn't */
+	if (do_putpmsg)
+		ret = (*do_putpmsg) (fd, ctlptr, datptr, band, flags);
+	up_read(&streams_call_sem);
+	return ret;
+}
+
+long asmlinkage sys_getpmsg(int fd, void *ctlptr, void *datptr, int band, int flags)
+{
+	int ret = -ENOSYS;
+	down_read(&streams_call_sem) ;	/* should return int, but doesn't */
+	if (do_getpmsg)
+		ret = (*do_getpmsg) (fd, ctlptr, datptr, band, flags);
+	up_read(&streams_call_sem);
+	return ret;
+}
+
+int register_streams_calls(int (*putpmsg) (int, void *, void *, int, int),
+			    int (*getpmsg) (int, void *, void *, int, int))
+{
+	int ret = 0;
+	down_write(&streams_call_sem) ;	/* should return int, but doesn't */
+	if (   (putpmsg != NULL && do_putpmsg != NULL)
+	    || (getpmsg != NULL && do_getpmsg != NULL)
+	   )
+		ret = -EBUSY;
+	else {
+		do_putpmsg = putpmsg;
+		do_getpmsg = getpmsg;
+	}
+	up_write(&streams_call_sem);
+	return ret ;
+}
+
 asmlinkage long sys_ni_syscall(void)
 {
 	return -ENOSYS;