Set cwd to '/' for the process executing insmod.

Ricardo has pointed out that under Solaris the cwd is set to '/'
during module load, while under Linux it is set to the callers cwd.
To handle this cleanly I've reworked the module *_init()/_exit()
macros so they call a *_setup()/_cleanup() function when any SPL
dependent module is loaded or unloaded.  This gives us a chance to
perform any needed modification of the process, in this case changing
the cwd.  It also handily provides a way to avoid creating wrapper
init()/exit() functions because the Solaris and Linux prototypes
differ slightly.  All dependent modules should now call the spl
helper macros spl_module_{init,exit}() instead of the native linux
versions.

Unfortunately, it appears that under Linux there has been no consistent
API in the kernel to set the cwd in a module.  Because of this I have
had to add more autoconf magic than I'd like.  However, what I have
done is correct and has been tested on RHEL5, SLES11, FC11, and CHAOS
kernels.

In addition, I have change the rootdir type from a 'void *' to the
correct 'vnode_t *' type.  And I've set rootdir to a non-NULL value.

1 files changed, 2 insertions, 0 deletions

diff --git a/include/sys/sysmacros.h b/include/sys/sysmacros.h
index 67afbfeb0..e66d8d991 100644
--- a/include/sys/sysmacros.h
+++ b/include/sys/sysmacros.h
@@ -144,6 +144,8 @@ extern int p0;
 /* Missing misc functions */
 extern int highbit(unsigned long i);
 extern uint32_t zone_get_hostid(void *zone);
+extern void spl_setup(void);
+extern void spl_cleanup(void);
 
 #define makedevice(maj,min) makedev(maj,min)