Preserve the errno value of an ioctl before calling free(3). Previously,

errno was very occasionally being clobbered, resulting in a bogus error from
dt_consume() and thus an error from dtrace(1).

MFC after:	2 weeks

3 files changed, 14 insertions, 11 deletions

diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c
index ae1ed00..072cb05 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_consume.c
@@ -2944,7 +2944,7 @@ dt_get_buf(dtrace_hdl_t *dtp, int cpu, dtrace_bufdesc_t **bufp)
 {
 	dtrace_optval_t size;
 	dtrace_bufdesc_t *buf = dt_zalloc(dtp, sizeof (*buf));
-	int error;
+	int error, rval;
 
 	if (buf == NULL)
 		return (-1);
@@ -2963,7 +2963,6 @@ dt_get_buf(dtrace_hdl_t *dtp, int cpu, dtrace_bufdesc_t **bufp)
 #else
 	if (dt_ioctl(dtp, DTRACEIOC_BUFSNAP, &buf) == -1) {
 #endif
-		dt_put_buf(dtp, buf);
 		/*
 		 * If we failed with ENOENT, it may be because the
 		 * CPU was unconfigured -- this is okay.  Any other
@@ -2971,10 +2970,12 @@ dt_get_buf(dtrace_hdl_t *dtp, int cpu, dtrace_bufdesc_t **bufp)
 		 */
 		if (errno == ENOENT) {
 			*bufp = NULL;
-			return (0);
-		}
+			rval = 0;
+		} else
+			rval = dt_set_errno(dtp, errno);
 
-		return (dt_set_errno(dtp, errno));
+		dt_put_buf(dtp, buf);
+		return (rval);
 	}
 
 	error = dt_unring_buf(dtp, buf);
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_map.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_map.c
index c6d92c8..6ab7cd9 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_map.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_map.c
@@ -39,7 +39,7 @@
 static int
 dt_strdata_add(dtrace_hdl_t *dtp, dtrace_recdesc_t *rec, void ***data, int *max)
 {
-	int maxformat;
+	int maxformat, rval;
 	dtrace_fmtdesc_t fmt;
 	void *result;
 
@@ -63,8 +63,9 @@ dt_strdata_add(dtrace_hdl_t *dtp, dtrace_recdesc_t *rec, void ***data, int *max)
 		return (dt_set_errno(dtp, EDT_NOMEM));
 
 	if (dt_ioctl(dtp, DTRACEIOC_FORMAT, &fmt) == -1) {
+		rval = dt_set_errno(dtp, errno);
 		free(fmt.dtfd_string);
-		return (dt_set_errno(dtp, errno));
+		return (rval);
 	}
 
 	while (rec->dtrd_format > (maxformat = *max)) {
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_work.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_work.c
index 68e64bb..d19fb88 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_work.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_work.c
@@ -184,7 +184,7 @@ dtrace_go(dtrace_hdl_t *dtp)
 {
 	dtrace_enable_io_t args;
 	void *dof;
-	int err;
+	int error, r;
 
 	if (dtp->dt_active)
 		return (dt_set_errno(dtp, EINVAL));
@@ -206,11 +206,12 @@ dtrace_go(dtrace_hdl_t *dtp)
 
 	args.dof = dof;
 	args.n_matched = 0;
-	err = dt_ioctl(dtp, DTRACEIOC_ENABLE, &args);
+	r = dt_ioctl(dtp, DTRACEIOC_ENABLE, &args);
+	error = errno;
 	dtrace_dof_destroy(dtp, dof);
 
-	if (err == -1 && (errno != ENOTTY || dtp->dt_vector == NULL))
-		return (dt_set_errno(dtp, errno));
+	if (r == -1 && (error != ENOTTY || dtp->dt_vector == NULL))
+		return (dt_set_errno(dtp, error));
 
 	if (dt_ioctl(dtp, DTRACEIOC_GO, &dtp->dt_beganon) == -1) {
 		if (errno == EACCES)