dt(4) ifdef sysctl

[Alexander Bluhm]

Hi,

sysctl witnesswatch gives an error message if the feature is not
compiled into the kernel.  I think dt(4) allowdt should do the same.

sysctl: kern.allowdt: value is not available

This removes a bit of unused code from ramdisk kernel.
The variable allowdt should be in the device, not in sysctl source.
We don't need #ifdef for extern and prototypes, without it code is
more readable.
Put the unneeded sysctl code into an #if NDT > 0.

ok?

By the way, can we enable dt(4) in GENERIC?  I use it quite often
and it is handy to have it is avaiable.  Missuse is prevented by
securelevel sysctl.  Any downside?

bluhm

Index: dev/dt/dt_dev.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/dev/dt/dt_dev.c,v
retrieving revision 1.12
diff -u -p -r1.12 dt_dev.c
--- dev/dt/dt_dev.c     26 Mar 2021 21:17:10 -0000      1.12
+++ dev/dt/dt_dev.c     22 Apr 2021 17:38:22 -0000
@@ -109,6 +109,8 @@ SIMPLEQ_HEAD(, dt_probe)    dt_probe_list;  
 struct rwlock                  dt_lock = RWLOCK_INITIALIZER("dtlk");
 volatile uint32_t              dt_tracing = 0; /* [K] # of processes tracing */
 
+int allowdt;
+
 void   dtattach(struct device *, struct device *, void *);
 int    dtopen(dev_t, int, int, struct proc *);
 int    dtclose(dev_t, int, int, struct proc *);
@@ -145,7 +147,6 @@ dtopen(dev_t dev, int flags, int mode, s
 {
        struct dt_softc *sc;
        int unit = minor(dev);
-       extern int allowdt;
 
        if (!allowdt)
                return EPERM;
Index: kern/kern_sysctl.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/kern_sysctl.c,v
retrieving revision 1.389
diff -u -p -r1.389 kern_sysctl.c
--- kern/kern_sysctl.c  8 Feb 2021 10:51:02 -0000       1.389
+++ kern/kern_sysctl.c  22 Apr 2021 17:38:22 -0000
@@ -114,24 +114,21 @@
 #endif
 
 #include "audio.h"
-#include "video.h"
+#include "dt.h"
 #include "pf.h"
+#include "video.h"
 
 extern struct forkstat forkstat;
 extern struct nchstats nchstats;
 extern int nselcoll, fscale;
 extern struct disklist_head disklist;
 extern fixpt_t ccpu;
-extern  long numvnodes;
-#if NAUDIO > 0
+extern long numvnodes;
+extern int allowdt;
 extern int audio_record_enable;
-#endif
-#if NVIDEO > 0
 extern int video_record_enable;
-#endif
 
 int allowkmem;
-int allowdt;
 
 int sysctl_diskinit(int, struct proc *);
 int sysctl_proc_args(int *, u_int, void *, size_t *, struct proc *);
@@ -142,12 +139,8 @@ int sysctl_proc_vmmap(int *, u_int, void
 int sysctl_intrcnt(int *, u_int, void *, size_t *);
 int sysctl_sensors(int *, u_int, void *, size_t *, void *, size_t);
 int sysctl_cptime2(int *, u_int, void *, size_t *, void *, size_t);
-#if NAUDIO > 0
 int sysctl_audio(int *, u_int, void *, size_t *, void *, size_t);
-#endif
-#if NVIDEO > 0
 int sysctl_video(int *, u_int, void *, size_t *, void *, size_t);
-#endif
 int sysctl_cpustats(int *, u_int, void *, size_t *, void *, size_t);
 int sysctl_utc_offset(void *, size_t *, void *, size_t);
 
@@ -479,10 +472,12 @@ kern_sysctl(int *name, u_int namelen, vo
                        return (EPERM);
                securelevel = level;
                return (0);
+#if NDT > 0
        case KERN_ALLOWDT:
                if (securelevel > 0)
                        return (sysctl_rdint(oldp, oldlenp, newp, allowdt));
                return (sysctl_int(oldp, oldlenp, newp, newlen,  &allowdt));
+#endif
        case KERN_ALLOWKMEM:
                if (securelevel > 0)
                        return (sysctl_rdint(oldp, oldlenp, newp, allowkmem));