Author: cem
Date: Sun Aug 27 17:12:30 2017
New Revision: 322954
URL: https://svnweb.freebsd.org/changeset/base/322954
Log:
Enhance debugibility of sysctl leaf re-use warnings
Print the full conflicting oid path, and include the function name in the
warning so it is clear that the warnings are sysctl-related.
PR: 221853
Submitted by: Fabian Keil <fk AT fabiankeil.de> (earlier version)
Sponsored by: Dell EMC Isilon
Modified:
head/sys/kern/kern_sysctl.c
Modified: head/sys/kern/kern_sysctl.c
==============================================================================
--- head/sys/kern/kern_sysctl.c Sun Aug 27 17:08:08 2017 (r322953)
+++ head/sys/kern/kern_sysctl.c Sun Aug 27 17:12:30 2017 (r322954)
@@ -323,6 +323,91 @@ sysctl_load_tunable_by_oid_locked(struct sysctl_oid *o
freeenv(penv);
}
+static int
+sbuf_printf_drain(void *arg __unused, const char *data, int len)
+{
+
+ return (printf("%.*s", len, data));
+}
+
+/*
+ * Locate the path to a given oid. Returns the length of the resulting path,
+ * or -1 if the oid was not found. nodes must have room for CTL_MAXNAME
+ * elements and be NULL initialized.
+ */
+static int
+sysctl_search_oid(struct sysctl_oid **nodes, struct sysctl_oid *needle)
+{
+ int indx;
+
+ SYSCTL_ASSERT_LOCKED();
+ indx = 0;
+ while (indx < CTL_MAXNAME && indx >= 0) {
+ if (nodes[indx] == NULL && indx == 0)
+ nodes[indx] = SLIST_FIRST(&sysctl__children);
+ else if (nodes[indx] == NULL)
+ nodes[indx] = SLIST_FIRST(&nodes[indx -
1]->oid_children);
+ else
+ nodes[indx] = SLIST_NEXT(nodes[indx], oid_link);
+
+ if (nodes[indx] == needle)
+ return (indx + 1);
+
+ if (nodes[indx] == NULL) {
+ indx--;
+ continue;
+ }
+
+ if ((nodes[indx]->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
+ indx++;
+ continue;
+ }
+ }
+ return (-1);
+}
+
+static void
+sysctl_warn_reuse(const char *func, struct sysctl_oid *leaf)
+{
+ struct sysctl_oid *nodes[CTL_MAXNAME];
+ char buf[128];
+ struct sbuf sb;
+ int rc, i;
+
+ (void)sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN | SBUF_INCLUDENUL);
+ sbuf_set_drain(&sb, sbuf_printf_drain, NULL);
+
+ sbuf_printf(&sb, "%s: can't re-use a leaf (", __func__);
+
+ memset(nodes, 0, sizeof(nodes));
+ rc = sysctl_search_oid(nodes, leaf);
+ if (rc > 0) {
+ for (i = 0; i < rc; i++)
+ sbuf_printf(&sb, "%s%.*s", nodes[i]->oid_name,
+ i != (rc - 1), ".");
+ } else {
+ sbuf_printf(&sb, "%s", leaf->oid_name);
+ }
+ sbuf_printf(&sb, ")!\n");
+
+ (void)sbuf_finish(&sb);
+}
+
+#ifdef SYSCTL_DEBUG
+static int
+sysctl_reuse_test(SYSCTL_HANDLER_ARGS)
+{
+ struct rm_priotracker tracker;
+
+ SYSCTL_RLOCK(&tracker);
+ sysctl_warn_reuse(__func__, oidp);
+ SYSCTL_RUNLOCK(&tracker);
+ return (0);
+}
+SYSCTL_PROC(_sysctl, 0, reuse_test, CTLTYPE_STRING|CTLFLAG_RD|CTLFLAG_MPSAFE,
+ 0, 0, sysctl_reuse_test, "-", "");
+#endif
+
void
sysctl_register_oid(struct sysctl_oid *oidp)
{
@@ -343,7 +428,7 @@ sysctl_register_oid(struct sysctl_oid *oidp)
p->oid_refcnt++;
return;
} else {
- printf("can't re-use a leaf (%s)!\n", p->oid_name);
+ sysctl_warn_reuse(__func__, p);
return;
}
}
@@ -715,8 +800,8 @@ sysctl_add_oid(struct sysctl_ctx_list *clist, struct s
SYSCTL_WUNLOCK();
return (oidp);
} else {
+ sysctl_warn_reuse(__func__, oidp);
SYSCTL_WUNLOCK();
- printf("can't re-use a leaf (%s)!\n", name);
return (NULL);
}
}
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