Here is a proposed "final" patch for the streams hooks. I think that it
takes into account all suggestions. I put the prototype in linux/sys.h.
This is for stock 2.4.19, and has been tested.
-- Dave
--- 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/sys.c.orig 2002-08-02 19:39:46.000000000 -0500
+++ kernel/sys.c 2002-10-10 15:00:45.000000000 -0500
@@ -167,6 +167,49 @@
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 = -EBUSY;
+ down_write(&streams_call_sem); /* should return int, but doesn't */
+ if ( (putpmsg == NULL || do_putpmsg == NULL)
+ && (getpmsg == NULL || do_getpmsg == NULL)) {
+ do_putpmsg = putpmsg;
+ do_getpmsg = getpmsg;
+ ret = 0;
+ }
+ up_write(&streams_call_sem);
+ return ret;
+}
+
asmlinkage long sys_ni_syscall(void)
{
return -ENOSYS;
@@ -1286,3 +1329,4 @@
EXPORT_SYMBOL(unregister_reboot_notifier);
EXPORT_SYMBOL(in_group_p);
EXPORT_SYMBOL(in_egroup_p);
+EXPORT_SYMBOL_GPL(register_streams_calls);
--- include/linux/sys.h.orig 2002-10-11 08:59:10.000000000 -0500
+++ include/linux/sys.h 2002-10-11 09:15:04.000000000 -0500
@@ -27,4 +27,16 @@
* These are system calls that haven't been implemented yet
* but have an entry in the table for future expansion..
*/
+
+/*
+ * These are registration routines for system calls that are
+ * implemented by loadable modules outside of the kernel
+ * source tree.
+ */
+#if !defined(__ASSEMBLY__)
+extern int
+register_streams_calls(int (*putpmsg) (int, void *, void *, int, int),
+ int (*getpmsg) (int, void *, void *, int, int)) ;
+
+#endif /* __ASSEMBLY__ */
#endif
