[monitoring-plugins] check_dns: some comments, small improvements

[Lorenz Kästle]

 Module: monitoring-plugins
 Branch: master
 Commit: c0d9580dac9779c40434c9b63a0ef4ef82b2e8ba
 Author: Lorenz Kästle <12514511+rincewinds...@users.noreply.github.com>
   Date: Sun Mar  9 12:11:02 2025 +0100
    URL: 
https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=c0d9580d

check_dns: some comments, small improvements

---

 plugins/check_dns.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/plugins/check_dns.c b/plugins/check_dns.c
index 7071c01f..e98c709f 100644
--- a/plugins/check_dns.c
+++ b/plugins/check_dns.c
@@ -106,14 +106,16 @@ int main(int argc, char **argv) {
                result = STATE_WARNING;
        }
 
-       char *address = NULL; /* comma separated str with addrs/ptrs (sorted) */
-       char **addresses = NULL;
-       size_t n_addresses = 0;
+       /* =====
+        * scan stdout, main results get retrieved here
+        * =====
+        */
+       char *address = NULL;    /* comma separated str with addrs/ptrs 
(sorted) */
+       char **addresses = NULL; // All addresses parsed from stdout
+       size_t n_addresses = 0;  // counter for retrieved addresses
        bool non_authoritative = false;
        bool is_nxdomain = false;
-       char *temp_buffer = NULL;
        bool parse_address = false; /* This flag scans for Address: but only 
after Name: */
-       /* scan stdout */
        for (size_t i = 0; i < chld_out.lines; i++) {
                if (addresses == NULL) {
                        addresses = malloc(sizeof(*addresses) * 10);
@@ -126,6 +128,7 @@ int main(int argc, char **argv) {
                }
 
                if (strcasestr(chld_out.line[i], ".in-addr.arpa") || 
strcasestr(chld_out.line[i], ".ip6.arpa")) {
+                       char *temp_buffer = NULL;
                        if ((temp_buffer = strstr(chld_out.line[i], "name = 
"))) {
                                addresses[n_addresses++] = strdup(temp_buffer + 
7);
                        } else {
@@ -137,6 +140,7 @@ int main(int argc, char **argv) {
                /* bug ID: 2946553 - Older versions of bind will use all 
available dns
                                                         servers, we have to 
match the one specified */
                if (strstr(chld_out.line[i], "Server:") && 
strlen(config.dns_server) > 0) {
+                       char *temp_buffer = NULL;
                        temp_buffer = strchr(chld_out.line[i], ':');
                        temp_buffer++;
 
@@ -159,6 +163,7 @@ int main(int argc, char **argv) {
                if (strstr(chld_out.line[i], "Name:")) {
                        parse_address = true;
                } else if (parse_address && (strstr(chld_out.line[i], 
"Address:") || strstr(chld_out.line[i], "Addresses:"))) {
+                       char *temp_buffer = NULL;
                        temp_buffer = index(chld_out.line[i], ':');
                        temp_buffer++;
 
@@ -216,6 +221,8 @@ int main(int argc, char **argv) {
                for (size_t i = 0; i < n_addresses; i++) {
                        slen += strlen(addresses[i]) + 1;
                }
+
+               // Temporary pointer adrp gets moved, address stays on the 
beginning
                adrp = address = malloc(slen);
                for (size_t i = 0; i < n_addresses; i++) {
                        if (i) {
@@ -232,7 +239,7 @@ int main(int argc, char **argv) {
        /* compare to expected address */
        if (result == STATE_OK && config.expected_address_cnt > 0) {
                result = STATE_CRITICAL;
-               temp_buffer = "";
+               char *temp_buffer = "";
                unsigned long expect_match = (1 << config.expected_address_cnt) 
- 1;
                unsigned long addr_match = (1 << n_addresses) - 1;