libdtrace: Add kinst support

kinst does not instantiate its probes automatically, it only does so on
demand via an ioctl interface implemented by /dev/kinst.  This change
modifies libdtrace to perform that work when the script references the
kinst provider, similar to the way pid provider probes are implemented.

Reviewed by:	markj
MFC after:	3 months
Sponsored by:	Google, Inc. (GSoC 2022)
Differential Revision:	https://reviews.freebsd.org/D36852

cddl/contrib/opensolaris/lib/libdtrace/common/dt_impl.h

@@ -323,6 +323,7 @@ struct dtrace_hdl {
 #endif
 	int dt_fd;		/* file descriptor for dtrace pseudo-device */
 	int dt_ftfd;		/* file descriptor for fasttrap pseudo-device */
+	int dt_kinstfd;		/* file descriptor for kinst pseudo-device */
 	int dt_fterr;		/* saved errno from failed open of dt_ftfd */
 	int dt_cdefs_fd;	/* file descriptor for C CTF debugging cache */
 	int dt_ddefs_fd;	/* file descriptor for D CTF debugging cache */

cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c

@@ -1173,6 +1173,7 @@ dt_vopen(int version, int flags, int *errp,
 	dtp->dt_version = version;
 	dtp->dt_fd = dtfd;
 	dtp->dt_ftfd = ftfd;
+	dtp->dt_kinstfd = -1;
 	dtp->dt_fterr = fterr;
 	dtp->dt_cdefs_fd = -1;
 	dtp->dt_ddefs_fd = -1;
@@ -1681,6 +1682,8 @@ dtrace_close(dtrace_hdl_t *dtp)
 		(void) close(dtp->dt_fd);
 	if (dtp->dt_ftfd != -1)
 		(void) close(dtp->dt_ftfd);
+	if (dtp->dt_kinstfd != -1)
+		(void) close(dtp->dt_kinstfd);
 	if (dtp->dt_cdefs_fd != -1)
 		(void) close(dtp->dt_cdefs_fd);
 	if (dtp->dt_ddefs_fd != -1)

cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.c

@@ -48,6 +48,7 @@
 #include <dt_list.h>
 #include <dt_pid.h>
 #include <dtrace.h>
+#include <kinst.h>
 
 static dt_provider_t *
 dt_provider_insert(dtrace_hdl_t *dtp, dt_provider_t *pvp, uint_t h)
@@ -699,6 +700,34 @@ dt_probe_info(dtrace_hdl_t *dtp,
 			prp = idp->di_data;
 		else if (pdp->dtpd_id != DTRACE_IDNONE)
 			prp = dt_probe_discover(pvp, pdp);
+
+		if (strcmp(pvp->pv_desc.dtvd_name, "kinst") == 0) {
+			dtrace_kinst_probedesc_t pd;
+
+			if (dtp->dt_kinstfd == -1) {
+				int fd;
+
+				fd = open("/dev/dtrace/kinst", O_WRONLY);
+				if (fd < 0) {
+					(void) dt_set_errno(dtp, errno);
+					return (NULL);
+				}
+				dtp->dt_kinstfd = fd;
+			}
+			memset(&pd, 0, sizeof(pd));
+			strlcpy(pd.kpd_func, pdp->dtpd_func,
+			    sizeof (pd.kpd_func));
+
+			if (n_is_glob)
+				pd.kpd_off = -1;
+			else
+				pd.kpd_off = strtol(pdp->dtpd_name, NULL, 10);
+			if (ioctl(dtp->dt_kinstfd, KINSTIOC_MAKEPROBE, &pd) !=
+			    0) {
+				(void) dt_set_errno(dtp, errno);
+				return (NULL);
+			}
+		}
 	}
 
 	/*

cddl/lib/libdtrace/Makefile

@@ -84,6 +84,7 @@ CFLAGS+= -DHAVE_ISSETUGID
 
 CFLAGS+=	-I${.OBJDIR} -I${.CURDIR} \
 		-I${SRCTOP}/sys/cddl/dev/dtrace/${MACHINE_ARCH} \
+		-I${SRCTOP}/sys/cddl/dev/kinst \
 		-I${SRCTOP}/sys/cddl/compat/opensolaris \
 		-I${SRCTOP}/cddl/compat/opensolaris/include \
 		-I${OPENSOLARIS_USR_DISTDIR}/head \