Right now ober_oid_cmp has inverted logic compared to other *cmp
functions. Specifically values greater than 0 are returned when
a is smaller than b.
Additionally, the value of 2 is only used b is a child of a, but
-1 is returned when a is a child of b.
This makes it harder than needed to use it with say the RB_*
family of functions, as well as wanting to test between the
parent-child relationship between two value.
Both these issues are not present in ax_oid_cmp and I would like
to copy the logic over from there.
Manpage bits mostly taken from strcmp(3)
I did a full scan of our tree and I could only find this function in
snmp(1) and snmpd(8) and patches for those are attaches as well.
No known 3rd party software is using this code.
Regress for libagentx, snmp and snmp pass.
OK for the next cycle?
martijn@
Index: lib/libutil/ber.c
===================================================================
RCS file: /cvs/src/lib/libutil/ber.c,v
retrieving revision 1.22
diff -u -p -r1.22 ber.c
--- lib/libutil/ber.c 29 Aug 2021 13:27:11 -0000 1.22
+++ lib/libutil/ber.c 1 Oct 2021 14:36:34 -0000
@@ -473,26 +473,21 @@ ober_string2oid(const char *oidstr, stru
int
ober_oid_cmp(struct ber_oid *a, struct ber_oid *b)
{
- size_t i;
- for (i = 0; i < a->bo_n && i < b->bo_n; i++) {
- if (a->bo_id[i] == b->bo_id[i])
- continue;
- else if (a->bo_id[i] < b->bo_id[i]) {
- /* b is a successor of a */
- return (1);
- } else {
- /* b is a predecessor of a */
+ size_t i, min;
+
+ min = a->bo_n < b->bo_n ? a->bo_n : b->bo_n;
+ for (i = 0; i < min; i++) {
+ if (a->bo_id[i] < b->bo_id[i])
return (-1);
- }
+ if (a->bo_id[i] > b->bo_id[i])
+ return (1);
}
- /* b is larger, but a child of a */
+ /* a is parent of b */
if (a->bo_n < b->bo_n)
- return (2);
- /* b is a predecessor of a */
+ return (-2);
+ /* a is child of b */
if (a->bo_n > b->bo_n)
- return -1;
-
- /* b and a are identical */
+ return 2;
return (0);
}
Index: lib/libutil/ober_oid_cmp.3
===================================================================
RCS file: /cvs/src/lib/libutil/ober_oid_cmp.3,v
retrieving revision 1.4
diff -u -p -r1.4 ober_oid_cmp.3
--- lib/libutil/ober_oid_cmp.3 12 Mar 2021 07:24:49 -0000 1.4
+++ lib/libutil/ober_oid_cmp.3 1 Oct 2021 14:36:34 -0000
@@ -66,26 +66,17 @@ returns the number of bytes written or 0
returns 0 on success or -1 on failure.
.Pp
.Fn ober_oid_cmp
-returns 0 when oids
+returns an integer greater than, equal to, or less than 0, according to whether
+the oid
+.Fa a
+is greater than, equal to, or less than the oid
+.Fa b .
+If the shortest length from
.Fa a
and
.Fa b
-are identical.
-If
-.Fa b
-is a successor of
-.Fa a ,
-1 is returned.
-If
-.Fa b
-is a predecessor of
-.Fa a ,
--1 is returned.
-If
-.Fa b
-is larger, but a child of
-.Fa a ,
-2 is returned.
+matches
+the weight of the integer is 2, else it is 1.
.Sh SEE ALSO
.Xr ober_add_string 3 ,
.Xr ober_get_string 3 ,
Index: usr.sbin/snmpd/traphandler.c
===================================================================
RCS file: /cvs/src/usr.sbin/snmpd/traphandler.c,v
retrieving revision 1.21
diff -u -p -r1.21 traphandler.c
--- usr.sbin/snmpd/traphandler.c 22 Feb 2021 11:31:09 -0000 1.21
+++ usr.sbin/snmpd/traphandler.c 1 Oct 2021 14:36:34 -0000
@@ -440,7 +440,7 @@ trapcmd_cmp(struct trapcmd *cmd1, struct
{
int ret;
- ret = ober_oid_cmp(cmd2->cmd_oid, cmd1->cmd_oid);
+ ret = ober_oid_cmp(cmd1->cmd_oid, cmd2->cmd_oid);
switch (ret) {
case 2:
/* cmd1 is a child of cmd2 */
Index: usr.bin/snmp/smi.c
===================================================================
RCS file: /cvs/src/usr.bin/snmp/smi.c,v
retrieving revision 1.14
diff -u -p -r1.14 smi.c
--- usr.bin/snmp/smi.c 4 Jan 2021 08:00:29 -0000 1.14
+++ usr.bin/snmp/smi.c 1 Oct 2021 14:36:34 -0000
@@ -506,7 +506,7 @@ smi_string2oid(const char *oidstr, struc
*p++ = '\0';
if ((oid = smi_findkey(sp)) != NULL) {
bcopy(&oid->o_id, &ko, sizeof(ko));
- if (o->bo_n && ober_oid_cmp(o, &ko) != 2)
+ if (o->bo_n && ober_oid_cmp(&ko, o) != 2)
return (-1);
bcopy(&ko, o, sizeof(*o));
errstr = NULL;
Index: usr.bin/snmp/snmpc.c
===================================================================
RCS file: /cvs/src/usr.bin/snmp/snmpc.c,v
retrieving revision 1.37
diff -u -p -r1.37 snmpc.c
--- usr.bin/snmp/snmpc.c 11 Aug 2021 18:53:45 -0000 1.37
+++ usr.bin/snmp/snmpc.c 1 Oct 2021 14:36:34 -0000
@@ -640,7 +640,7 @@ snmpc_walk(int argc, char *argv[])
}
while (1) {
for (i = 0; i < walk_skip_len; i++) {
- skip_cmp = ober_oid_cmp(&(walk_skip[i]), &noid);
+ skip_cmp = ober_oid_cmp(&noid, &(walk_skip[i]));
if (skip_cmp == 0 || skip_cmp == 2) {
bcopy(&(walk_skip[i]), &noid, sizeof(noid));
noid.bo_id[noid.bo_n -1]++;
@@ -673,19 +673,19 @@ snmpc_walk(int argc, char *argv[])
value->be_type == BER_TYPE_EOC)
break;
for (i = 0; i < walk_skip_len; i++) {
- skip_cmp = ober_oid_cmp(&(walk_skip[i]), &noid);
+ skip_cmp = ober_oid_cmp(&noid, &(walk_skip[i]));
if (skip_cmp == 0 || skip_cmp == 2)
break;
}
if (i < walk_skip_len)
continue;
- prev_cmp = ober_oid_cmp(&loid, &noid);
+ prev_cmp = ober_oid_cmp(&noid, &loid);
if (walk_check_increase && prev_cmp == -1)
errx(1, "OID not increasing");
- if (prev_cmp == 0 || ober_oid_cmp(&oid, &noid) != 2)
+ if (prev_cmp == 0 || ober_oid_cmp(&noid, &oid) != 2)
break;
if (walk_end.bo_n != 0 &&
- ober_oid_cmp(&walk_end, &noid) != -1)
+ ober_oid_cmp(&noid, &walk_end) != -1)
break;
if (!snmpc_print(varbind))
@@ -899,7 +899,7 @@ snmpc_df(int argc, char *argv[])
for (; varbind != NULL; varbind = varbind->be_next) {
if (ober_scanf_elements(varbind, "{os", &oid,
&string) == -1 ||
- ober_oid_cmp(&descroid, &oid) != 2)
+ ober_oid_cmp(&oid, &descroid) != 2)
break;
rows++;
}
@@ -913,7 +913,7 @@ snmpc_df(int argc, char *argv[])
rows--;
continue;
}
- if (ober_oid_cmp(&descroid, &oid) != 2)
+ if (ober_oid_cmp(&oid, &descroid) != 2)
break;
df[i].index = oid.bo_id[oid.bo_n - 1];
if ((df[i].descr = smi_print_element(&oid, elm, 0,
