Implement gctl_change_param() function, which changes value of existing

parameter.

MFC after:	1 week

2 files changed, 28 insertions, 0 deletions

diff --git a/sbin/geom/misc/subr.c b/sbin/geom/misc/subr.c
index 1faafe5..745d919 100644
--- a/sbin/geom/misc/subr.c
+++ b/sbin/geom/misc/subr.c
@@ -388,3 +388,29 @@ gctl_get_ascii(struct gctl_req *req, const char *pfmt, ...)
 	va_end(ap);
 	return (p);
 }
+
+int
+gctl_change_param(struct gctl_req *req, const char *name, int len,
+    const void *value)
+{
+	struct gctl_req_arg *ap;
+	unsigned i;
+
+	if (req == NULL || req->error != NULL)
+		return (EDOOFUS);
+	for (i = 0; i < req->narg; i++) {
+		ap = &req->arg[i];
+		if (strcmp(ap->name, name) != 0)
+			continue;
+		ap->value = __DECONST(void *, value);
+		if (len >= 0) {
+			ap->flag &= ~GCTL_PARAM_ASCII;
+			ap->len = len;
+		} else if (len < 0) {
+			ap->flag |= GCTL_PARAM_ASCII;
+			ap->len = strlen(value) + 1;
+		}
+		return (0);
+	}
+	return (ENOENT);
+}
diff --git a/sbin/geom/misc/subr.h b/sbin/geom/misc/subr.h
index 865e855..4c54142 100644
--- a/sbin/geom/misc/subr.h
+++ b/sbin/geom/misc/subr.h
@@ -45,4 +45,6 @@ void gctl_error(struct gctl_req *req, const char *error, ...) __printflike(2, 3)
 int gctl_get_int(struct gctl_req *req, const char *pfmt, ...) __printflike(2, 3);
 intmax_t gctl_get_intmax(struct gctl_req *req, const char *pfmt, ...) __printflike(2, 3);
 const char *gctl_get_ascii(struct gctl_req *req, const char *pfmt, ...) __printflike(2, 3);
+int gctl_change_param(struct gctl_req *req, const char *name, int len,
+    const void *value);
 #endif	/* !_SUBR_H_ */