Events: avoid evaluating intermediates for unneeded events

[exim.git] / src / src / dns.c

diff --git a/src/src/dns.c b/src/src/dns.c
index 297b8b88da7f253be56807459cb5d9e38c4c14e2..6ef6b7784b03343bff3a2b3fae635577d8300d37 100644 (file)
--- a/src/src/dns.c
+++ b/src/src/dns.c
@@ -240,8 +240,7 @@ uschar *pp = buffer;
 if (Ustrchr(string, ':') == NULL)
 #endif
   {
 if (Ustrchr(string, ':') == NULL)
 #endif
   {

-  int i;
-  for (i = 0; i < 4; i++)
+  for (int i = 0; i < 4; i++)

     {
     const uschar *ppp = p;
     while (ppp > string && ppp[-1] != '.') ppp--;
     {
     const uschar *ppp = p;
     while (ppp > string && ppp[-1] != '.') ppp--;


@@ -259,7 +258,6 @@ abbreviation in the textual form. */
 #if HAVE_IPV6
 else
   {
 #if HAVE_IPV6
 else
   {

-  int i;

   int v6[4];
   (void)host_aton(string, v6);
 
   int v6[4];
   (void)host_aton(string, v6);
 


@@ -267,12 +265,9 @@ else
   nibble, and look in the ip6.int domain. The domain was subsequently
   changed to ip6.arpa. */
 
   nibble, and look in the ip6.int domain. The domain was subsequently
   changed to ip6.arpa. */
 

-  for (i = 3; i >= 0; i--)
-    {
-    int j;
-    for (j = 0; j < 32; j += 4)
+  for (int i = 3; i >= 0; i--)
+    for (int j = 0; j < 32; j += 4)

       pp += sprintf(CS pp, "%x.", (v6[i] >> j) & 15);
       pp += sprintf(CS pp, "%x.", (v6[i] >> j) & 15);

-    }

   Ustrcpy(pp, "ip6.arpa.");
 
   /* Another way of doing IPv6 reverse lookups was proposed in conjunction
   Ustrcpy(pp, "ip6.arpa.");
 
   /* Another way of doing IPv6 reverse lookups was proposed in conjunction


@@ -287,7 +282,7 @@ else
   Ustrcpy(pp, "\\[x");
   pp += 3;
 
   Ustrcpy(pp, "\\[x");
   pp += 3;
 

-  for (i = 0; i < 4; i++)
+  for (int i = 0; i < 4; i++)

     {
     sprintf(pp, "%08X", v6[i]);
     pp += 8;
     {
     sprintf(pp, "%08X", v6[i]);
     pp += 8;


@@ -467,11 +462,10 @@ static const uschar *
 dns_extract_auth_name(const dns_answer * dnsa) /* FIXME: const dns_answer */
 {
 dns_scan dnss;
 dns_extract_auth_name(const dns_answer * dnsa) /* FIXME: const dns_answer */
 {
 dns_scan dnss;

-dns_record * rr;

 const HEADER * h = (const HEADER *) dnsa->answer;
 
 if (h->nscount && h->aa)
 const HEADER * h = (const HEADER *) dnsa->answer;
 
 if (h->nscount && h->aa)

-  for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
+  for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);

        rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == (h->ancount ? T_NS : T_SOA))
       return string_copy(rr->name);
        rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == (h->ancount ? T_NS : T_SOA))
       return string_copy(rr->name);


@@ -639,6 +633,10 @@ up nameservers that produce this error continually, so there is the option of
 providing a list of domains for which this is treated as a non-existent
 host.
 
 providing a list of domains for which this is treated as a non-existent
 host.
 

+The dns_answer structure is pretty big; enough to hold a max-sized DNS message
+- so best allocated from fast-release memory.  As of writing, all our callers
+use a stack-auto variable.
+

 Arguments:
   dnsa      pointer to dns_answer structure
   name      name to look up
 Arguments:
   dnsa      pointer to dns_answer structure
   name      name to look up


@@ -712,7 +710,11 @@ lookup, which constructs the names itself, so they should be OK. Besides,
 bitstring labels don't conform to normal name syntax. (But the aren't used any
 more.)
 
 bitstring labels don't conform to normal name syntax. (But the aren't used any
 more.)
 

-For SRV records, we omit the initial _smtp._tcp. components at the start. */
+For SRV records, we omit the initial _smtp._tcp. components at the start.
+The check has been seen to bite on the destination of a SRV lookup that
+initiall hit a CNAME, for which the next name had only two components.
+RFC2782 makes no mention of the possibiility of CNAMES, but the Wikipedia
+article on SRV says they are not a valid configuration. */

 
 #ifndef STAND_ALONE   /* Omit this for stand-alone tests */
 
 
 #ifndef STAND_ALONE   /* Omit this for stand-alone tests */
 


@@ -728,8 +730,8 @@ if (check_dns_names_pattern[0] != 0 && type != T_PTR && type != T_TXT)
 
   if (type == T_SRV || type == T_TLSA)
     {
 
   if (type == T_SRV || type == T_TLSA)
     {

-    while (*checkname++ != '.');
-    while (*checkname++ != '.');
+    while (*checkname && *checkname++ != '.') ;
+    while (*checkname && *checkname++ != '.') ;

     }
 
   if (pcre_exec(regex_check_dns_names, NULL, CCS checkname, Ustrlen(checkname),
     }
 
   if (pcre_exec(regex_check_dns_names, NULL, CCS checkname, Ustrlen(checkname),


@@ -869,7 +871,6 @@ int
 dns_lookup(dns_answer *dnsa, const uschar *name, int type,
   const uschar **fully_qualified_name)
 {
 dns_lookup(dns_answer *dnsa, const uschar *name, int type,
   const uschar **fully_qualified_name)
 {

-int i;

 const uschar *orig_name = name;
 BOOL secure_so_far = TRUE;
 
 const uschar *orig_name = name;
 BOOL secure_so_far = TRUE;
 


@@ -880,10 +881,10 @@ resolvers hiding behind a config variable. Loop to follow CNAME chains so far,
 but no further...  The testsuite tests the latter case, mostly assuming that the
 former will work. */
 
 but no further...  The testsuite tests the latter case, mostly assuming that the
 former will work. */
 

-for (i = 0; i <= dns_cname_loops; i++)
+for (int i = 0; i <= dns_cname_loops; i++)

   {
   uschar * data;
   {
   uschar * data;

-  dns_record *rr, cname_rr, type_rr;
+  dns_record cname_rr, type_rr;

   dns_scan dnss;
   int rc;
 
   dns_scan dnss;
   int rc;
 


@@ -899,7 +900,7 @@ for (i = 0; i <= dns_cname_loops; i++)
   area in the dnsa block. */
 
   cname_rr.data = type_rr.data = NULL;
   area in the dnsa block. */
 
   cname_rr.data = type_rr.data = NULL;

-  for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
+  for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);

        rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == type)
       {
        rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
     if (rr->type == type)
       {


@@ -1101,7 +1102,7 @@ switch (type)
          && (h->rcode == NOERROR || h->rcode == NXDOMAIN)
          && ntohs(h->qdcount) == 1 && ntohs(h->ancount) == 0
          && ntohs(h->nscount) >= 1)
          && (h->rcode == NOERROR || h->rcode == NXDOMAIN)
          && ntohs(h->qdcount) == 1 && ntohs(h->ancount) == 0
          && ntohs(h->nscount) >= 1)

-           dnsa->answerlen = MAXPACKET;
+           dnsa->answerlen = sizeof(dnsa->answer);

 
       for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
           rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)
 
       for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
           rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)


@@ -1213,8 +1214,7 @@ else
   if (rr->data + 16 <= dnsa_lim)
     {
     struct in6_addr in6;
   if (rr->data + 16 <= dnsa_lim)
     {
     struct in6_addr in6;

-    int i;
-    for (i = 0; i < 16; i++) in6.s6_addr[i] = rr->data[i];
+    for (int i = 0; i < 16; i++) in6.s6_addr[i] = rr->data[i];

     yield = store_get(sizeof(dns_address) + 50);
     inet_ntop(AF_INET6, &in6, CS yield->address, 50);
     yield->next = NULL;
     yield = store_get(sizeof(dns_address) + 50);
     inet_ntop(AF_INET6, &in6, CS yield->address, 50);
     yield->next = NULL;