From af62c4ddd0117e474529232ea3657578ad79b0fb Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Mon, 17 Nov 2014 22:22:16 +0000
Subject: [PATCH] DTrace imposes a 128-byte limit on the length of the function
 component of a probe name. When dtrace -G builds up a DOF section for the
 specified provider(s), the probe function names are truncated to fit in this
 limit. The DOF is later used to build the symbol table for the generated
 object file, so the table can end up with truncated references, causing link
 errors.

Instead of potentially truncating symbol table entries, write the full
function name to the DOF string table and allow the kernel to enforce the
128-byte function name limit when a process attempts to load its DOF.

PR:		194757
Differential Revision:	https://reviews.freebsd.org/D1175
Reviewed by:	rpaulo
MFC after:	2 weeks
---
 .../opensolaris/lib/libdtrace/common/dt_dof.c |  2 +-
 .../lib/libdtrace/common/dt_provider.c        | 37 +++++++++----------
 .../lib/libdtrace/common/dt_provider.h        |  4 +-
 3 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_dof.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_dof.c
index 54426834d501..0b531c5e6883 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_dof.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_dof.c
@@ -469,7 +469,7 @@ dof_add_probe(dt_idhash_t *dhp, dt_ident_t *idp, void *data)
 		 * locally so an alternate symbol is added for the purpose
 		 * of this relocation.
 		 */
-		if (pip->pi_rname[0] == '\0')
+		if (pip->pi_rname == NULL)
 			dofr.dofr_name = dofpr.dofpr_func;
 		else
 			dofr.dofr_name = dof_add_string(ddo, pip->pi_rname);
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.c
index 0f1bfe07b7b1..6acb86b155ba 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.c
@@ -520,6 +520,8 @@ dt_probe_destroy(dt_probe_t *prp)
 
 	for (pip = prp->pr_inst; pip != NULL; pip = pip_next) {
 		pip_next = pip->pi_next;
+		dt_free(dtp, pip->pi_rname);
+		dt_free(dtp, pip->pi_fname);
 		dt_free(dtp, pip->pi_offs);
 		dt_free(dtp, pip->pi_enoffs);
 		dt_free(dtp, pip);
@@ -552,28 +554,18 @@ dt_probe_define(dt_provider_t *pvp, dt_probe_t *prp,
 		if ((pip = dt_zalloc(dtp, sizeof (*pip))) == NULL)
 			return (-1);
 
-		if ((pip->pi_offs = dt_zalloc(dtp,
-		    sizeof (uint32_t))) == NULL) {
-			dt_free(dtp, pip);
-			return (-1);
-		}
+		if ((pip->pi_offs = dt_zalloc(dtp, sizeof (uint32_t))) == NULL)
+			goto nomem;
 
 		if ((pip->pi_enoffs = dt_zalloc(dtp,
-		    sizeof (uint32_t))) == NULL) {
-			dt_free(dtp, pip->pi_offs);
-			dt_free(dtp, pip);
-			return (-1);
-		}
+		    sizeof (uint32_t))) == NULL)
+			goto nomem;
 
-		(void) strlcpy(pip->pi_fname, fname, sizeof (pip->pi_fname));
-		if (rname != NULL) {
-			if (strlen(rname) + 1 > sizeof (pip->pi_rname)) {
-				dt_free(dtp, pip->pi_offs);
-				dt_free(dtp, pip);
-				return (dt_set_errno(dtp, EDT_COMPILER));
-			}
-			(void) strcpy(pip->pi_rname, rname);
-		}
+		if ((pip->pi_fname = strdup(fname)) == NULL)
+			goto nomem;
+
+		if (rname != NULL && (pip->pi_rname = strdup(rname)) == NULL)
+			goto nomem;
 
 		pip->pi_noffs = 0;
 		pip->pi_maxoffs = 1;
@@ -618,6 +610,13 @@ dt_probe_define(dt_provider_t *pvp, dt_probe_t *prp,
 	(*offs)[(*noffs)++] = offset;
 
 	return (0);
+
+nomem:
+	dt_free(dtp, pip->pi_fname);
+	dt_free(dtp, pip->pi_enoffs);
+	dt_free(dtp, pip->pi_offs);
+	dt_free(dtp, pip);
+	return (dt_set_errno(dtp, EDT_NOMEM));
 }
 
 /*
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.h b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.h
index af4ec33dcb9a..2752baae32da 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.h
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_provider.h
@@ -64,8 +64,8 @@ typedef struct dt_probe_iter {
 } dt_probe_iter_t;
 
 typedef struct dt_probe_instance {
-	char pi_fname[DTRACE_FUNCNAMELEN]; /* function name */
-	char pi_rname[DTRACE_FUNCNAMELEN + 20]; /* mangled relocation name */
+	char *pi_fname;			/* function name */
+	char *pi_rname;			/* mangled relocation name */
 	uint32_t *pi_offs;		/* offsets into the function */
 	uint32_t *pi_enoffs;		/* is-enabled offsets */
 	uint_t pi_noffs;		/* number of offsets */