Use provided buffer in dns_resource_key_to_string

When the buffer is allocated on the stack we do not have to check for
failure everywhere. This is especially useful in debug statements, because
we can put dns_resource_key_to_string() call in the debug statement, and
we do not need a seperate if (log_level >= LOG_DEBUG) for the conversion.

dns_resource_key_to_string() is changed not to provide any whitespace
padding. Most callers were stripping the whitespace with strstrip(),
and it did not look to well anyway. systemd-resolve output is not column
aligned anymore.

The result of the conversion is not stored in DnsTransaction object
anymore. It is used only for debugging, so it seems fine to generate it
when needed.

Various debug statements are extended to provide more information.

1 files changed, 10 insertions, 21 deletions

diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 4e2dd46155..d0a86ef206 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -324,31 +324,22 @@ const struct hash_ops dns_resource_key_hash_ops = {
         .compare = dns_resource_key_compare_func
 };
 
-int dns_resource_key_to_string(const DnsResourceKey *key, char **ret) {
-        char cbuf[strlen("CLASS") + DECIMAL_STR_MAX(uint16_t)], tbuf[strlen("TYPE") + DECIMAL_STR_MAX(uint16_t)];
+char* dns_resource_key_to_string(const DnsResourceKey *key, char *buf, size_t buf_size) {
         const char *c, *t;
-        char *s;
+        char *ans = buf;
 
         /* If we cannot convert the CLASS/TYPE into a known string,
            use the format recommended by RFC 3597, Section 5. */
 
         c = dns_class_to_string(key->class);
-        if (!c) {
-                sprintf(cbuf, "CLASS%u", key->class);
-                c = cbuf;
-        }
-
         t = dns_type_to_string(key->type);
-        if (!t){
-                sprintf(tbuf, "TYPE%u", key->type);
-                t = tbuf;
-        }
 
-        if (asprintf(&s, "%s %s %-5s", dns_resource_key_name(key), c, t) < 0)
-                return -ENOMEM;
+        snprintf(buf, buf_size, "%s %s%s%.0u %s%s%.0u",
+                 dns_resource_key_name(key),
+                 c ?: "", c ? "" : "CLASS", c ? 0 : key->class,
+                 t ?: "", t ? "" : "TYPE", t ? 0 : key->class);
 
-        *ret = s;
-        return 0;
+        return ans;
 }
 
 bool dns_resource_key_reduce(DnsResourceKey **a, DnsResourceKey **b) {
@@ -846,8 +837,8 @@ static char *format_txt(DnsTxtItem *first) {
 }
 
 const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
-        _cleanup_free_ char *k = NULL, *t = NULL;
-        char *s;
+        _cleanup_free_ char *t = NULL;
+        char *s, k[DNS_RESOURCE_KEY_STRING_MAX];
         int r;
 
         assert(rr);
@@ -855,9 +846,7 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
         if (rr->to_string)
                 return rr->to_string;
 
-        r = dns_resource_key_to_string(rr->key, &k);
-        if (r < 0)
-                return NULL;
+        dns_resource_key_to_string(rr->key, k, sizeof(k));
 
         switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {