[DTrace-devel] [PATCH v2 2/4] fbt: clean up fprobe/kprobe support

[Kris Van Hees]

Instead of leaking dt_fbt_fprobe outside of the FBT provider so that
there is *something* to represent the FBT provider, use a minimal
dt_fbt that does the job of providing a hook to the populate function,
which then will update dt_fbt from dt_fbt_fprobe o dt_fbt_kprobe
depending on what implementation is available (fprobe is preferred).

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 libdtrace/dt_prov_fbt.c | 13 ++++++++++---
 libdtrace/dt_provider.c |  2 +-
 libdtrace/dt_provider.h |  3 +--
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/libdtrace/dt_prov_fbt.c b/libdtrace/dt_prov_fbt.c
index da288401..8d8545c4 100644
--- a/libdtrace/dt_prov_fbt.c
+++ b/libdtrace/dt_prov_fbt.c
@@ -57,6 +57,9 @@ static const dtrace_pattr_t	pattr = {
 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
 };
 
+dt_provimpl_t			dt_fbt_fprobe;
+dt_provimpl_t			dt_fbt_kprobe;
+
 /*
  * Scan the PROBE_LIST file and add entry and return probes for every function
  * that is listed.
@@ -64,7 +67,6 @@ static const dtrace_pattr_t	pattr = {
 static int populate(dtrace_hdl_t *dtp)
 {
 	dt_provider_t		*prv;
-	dt_provimpl_t		*impl;
 	FILE			*f;
 	char			*buf = NULL;
 	char			*p;
@@ -73,9 +75,9 @@ static int populate(dtrace_hdl_t *dtp)
 	dtrace_syminfo_t	sip;
 	dtrace_probedesc_t	pd;
 
-	impl = BPF_HAS(dtp, BPF_FEAT_FENTRY) ? &dt_fbt_fprobe : &dt_fbt_kprobe;
+	dt_fbt = BPF_HAS(dtp, BPF_FEAT_FENTRY) ? dt_fbt_kprobe : dt_fbt_kprobe;
 
-	prv = dt_provider_create(dtp, prvname, impl, &pattr, NULL);
+	prv = dt_provider_create(dtp, prvname, &dt_fbt, &pattr, NULL);
 	if (prv == NULL)
 		return -1;			/* errno already set */
 
@@ -463,3 +465,8 @@ dt_provimpl_t	dt_fbt_kprobe = {
 	.detach		= &kprobe_detach,
 	.probe_destroy	= &dt_tp_probe_destroy,
 };
+
+dt_provimpl_t	dt_fbt = {
+	.name		= prvname,
+	.populate	= &populate,
+};
diff --git a/libdtrace/dt_provider.c b/libdtrace/dt_provider.c
index ca8b53df..1e2e844e 100644
--- a/libdtrace/dt_provider.c
+++ b/libdtrace/dt_provider.c
@@ -30,7 +30,7 @@
 const dt_provimpl_t *dt_providers[] = {
 	&dt_dtrace,		/* list dt_dtrace first */
 	&dt_cpc,
-	&dt_fbt_fprobe,
+	&dt_fbt,
 	&dt_io,
 	&dt_ip,
 	&dt_lockstat,
diff --git a/libdtrace/dt_provider.h b/libdtrace/dt_provider.h
index 8f143dce..f62137de 100644
--- a/libdtrace/dt_provider.h
+++ b/libdtrace/dt_provider.h
@@ -76,8 +76,7 @@ typedef struct dt_provimpl {
 /* list dt_dtrace first */
 extern dt_provimpl_t dt_dtrace;
 extern dt_provimpl_t dt_cpc;
-extern dt_provimpl_t dt_fbt_fprobe;
-extern dt_provimpl_t dt_fbt_kprobe;
+extern dt_provimpl_t dt_fbt;
 extern dt_provimpl_t dt_io;
 extern dt_provimpl_t dt_ip;
 extern dt_provimpl_t dt_lockstat;
-- 
2.45.2