Add convenience function kernel_sysctlbyname() for kernel consumers,

so they don't have to roll their own sysctlbyname function.

2 files changed, 27 insertions, 1 deletions

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index 206322c..99f2d69 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -844,7 +844,8 @@ sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l)
 }
 
 int
-kernel_sysctl(struct proc *p, int *name, u_int namelen, void *old, size_t *oldlenp, void *new, size_t newlen, size_t *retval)
+kernel_sysctl(struct proc *p, int *name, u_int namelen, void *old,
+    size_t *oldlenp, void *new, size_t newlen, size_t *retval)
 {
 	int error = 0;
 	struct sysctl_req req;
@@ -902,6 +903,28 @@ kernel_sysctl(struct proc *p, int *name, u_int namelen, void *old, size_t *oldle
 	return (error);
 }
 
+int
+kernel_sysctlbyname(struct proc *p, char *name, void *old, size_t *oldlenp,
+    void *new, size_t newlen, size_t *retval)
+{
+        int oid[CTL_MAXNAME];
+        size_t oidlen;
+	int error, plen;
+
+	oid[0] = 0;		/* sysctl internal magic */
+	oid[1] = 3;		/* name2oid */
+	oidlen = sizeof(oid);
+
+	error = kernel_sysctl(p, oid, 2, oid, &oidlen,
+	    (void *)name, strlen(name), &plen);
+	if (error)
+		return (error);
+
+	error = kernel_sysctl(p, oid, plen / sizeof(int), old, oldlenp,
+	    new, newlen, retval);
+	return (error);
+}
+
 /*
  * Transfer function to/from user space.
  */
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 2c81d26..2de78a2 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -582,6 +582,9 @@ void	sysctl_unregister_set(struct linker_set *lsp);
 int	kernel_sysctl(struct proc *p, int *name, u_int namelen, void *old,
 		      size_t *oldlenp, void *new, size_t newlen,
 		      size_t *retval);
+int	kernel_sysctlbyname(struct proc *p, char *name,
+		void *old, size_t *oldlenp, void *new, size_t newlen,
+		size_t *retval);
 int	userland_sysctl(struct proc *p, int *name, u_int namelen, void *old,
 			size_t *oldlenp, int inkernel, void *new, size_t newlen,
 			size_t *retval);