[DTrace-devel] [PATCH 18/38] Add a provider-specific probe_add_clause for underlying probes

[eugene.loh at oracle.com]

From: Eugene Loh <eugene.loh at oracle.com>

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
---
 libdtrace/dt_prov_uprobe.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/libdtrace/dt_prov_uprobe.c b/libdtrace/dt_prov_uprobe.c
index c77063a8..5dbd75e3 100644
--- a/libdtrace/dt_prov_uprobe.c
+++ b/libdtrace/dt_prov_uprobe.c
@@ -129,6 +129,38 @@ static void probe_destroy(dtrace_hdl_t *dtp, void *datap)
 	free_probe_list(dtp, datap);
 }
 
+/*
+ * Add clause to probe.
+ */
+static int probe_add_clause(dtrace_hdl_t *dtp, dt_probe_t *prp, dt_ident_t *idp)
+{
+	const list_probe_t	*pup;
+
+	for (pup = prp->prv_data; pup != NULL; pup = dt_list_next(pup)) {
+		dt_probe_t		*uprp = pup->probe;
+		dt_probe_clause_t	*prev, *pcp;
+
+		/*
+		 * Check if the clause is already there.  Since the clauses
+		 * are added "in order," we only need to check the previous
+		 * entry.
+		 */
+		prev = dt_list_prev(&uprp->clauses);
+		if (prev && strcmp(prev->clause->di_name, idp->di_name) == 0)
+			continue;
+
+		/*
+		 * Add the clause.
+		 */
+		pcp = dt_zalloc(dtp, sizeof(dt_probe_clause_t));
+		if (pcp == NULL)
+			return -1;
+		pcp->clause = idp;
+		dt_list_append(&uprp->clauses, pcp);
+	}
+
+	return 0;
+}
 
 /*
  * Look up or create an underlying (real) probe, corresponding directly to a
@@ -811,6 +843,7 @@ dt_provimpl_t	dt_pid = {
 	.prog_type	= BPF_PROG_TYPE_UNSPEC,
 	.provide_probe	= &provide_pid_probe,
 	.enable		= &enable_pid,
+	.probe_add_clause = &probe_add_clause,
 	.probe_destroy	= &probe_destroy,
 };
 
@@ -822,5 +855,6 @@ dt_provimpl_t	dt_usdt = {
 	.prog_type	= BPF_PROG_TYPE_UNSPEC,
 	.provide_probe	= &provide_usdt_probe,
 	.enable		= &enable_usdt,
+	.probe_add_clause = &probe_add_clause,
 	.probe_destroy	= &probe_destroy,
 };
-- 
2.18.4