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Enhance debugibility of sysctl leaf re-use warnings

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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
This commit is contained in:
Conrad Meyer 2017-08-27 17:12:30 +00:00
parent 9a1f7ce50c
commit 4ae2ade114
1 changed files with 87 additions and 2 deletions
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89
sys/kern/kern_sysctl.c
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@ -323,6 +323,91 @@ sysctl_load_tunable_by_oid_locked(struct sysctl_oid *oidp)
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 sysctl_oid_list *parent,
SYSCTL_WUNLOCK();
return (oidp);
} else {
sysctl_warn_reuse(__func__, oidp);
SYSCTL_WUNLOCK();
printf("can't re-use a leaf (%s)!\n", name);
return (NULL);
}
}