Commit 3451e888 authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

- Henrik Stoerner: found out that C-ARES does not look at the /etc/host.conf 

  file to determine the sequence in which to search /etc/hosts and DNS.  So on
  systems where this order is defined by /etc/host.conf instead of a "lookup"
  entry in /etc/resolv.conf, C-ARES will always default to looking in DNS
  first, and /etc/hosts second.

  c-ares now looks at

  1) resolv.conf (for the "lookup" line);
  2) nsswitch.fon (for the "hosts:" line);
  3) host.conf (for the "order" line).

  First match wins.
parent 12dc142a

ares/CHANGES

+14 −0
Original line number Diff line number Diff line
@@ -2,6 +2,20 @@ 


* September 26



- Henrik Stoerner: found out that C-ARES does not look at the /etc/host.conf

  file to determine the sequence in which to search /etc/hosts and DNS.  So on

  systems where this order is defined by /etc/host.conf instead of a "lookup"

  entry in /etc/resolv.conf, C-ARES will always default to looking in DNS

  first, and /etc/hosts second.



  c-ares now looks at



  1) resolv.conf (for the "lookup" line);

  2) nsswitch.fon (for the "hosts:" line);

  3) host.conf (for the "order" line).



  First match wins.



- Dominick Meglio patched: C-ares on Windows assumed that the HOSTS file is

  located in a static location. It assumed

  C:\Windows\System32\Drivers\Etc. This is a poor assumption to make. In fact,

ares/ares_init.c

+36 −8
Original line number Diff line number Diff line
@@ -55,7 +55,8 @@ static int init_by_environment(ares_channel channel); 
static int init_by_resolv_conf(ares_channel channel);

static int init_by_defaults(ares_channel channel);

static int config_domain(ares_channel channel, char *str);

static int config_lookup(ares_channel channel, const char *str);

static int config_lookup(ares_channel channel, const char *str,

                         const char *bindch, const char *filech);

static int config_nameserver(struct server_state **servers, int *nservers,

			     char *str);

static int config_sortlist(struct apattern **sortlist, int *nsort,
@@ -549,7 +550,7 @@ DhcpNameServer 
      if ((p = try_config(line, "domain")))

        status = config_domain(channel, p);

      else if ((p = try_config(line, "lookup")) && !channel->lookups)

        status = config_lookup(channel, p);

        status = config_lookup(channel, p, "bind", "file");

      else if ((p = try_config(line, "search")))

        status = set_search(channel, p);

      else if ((p = try_config(line, "nameserver")) && channel->nservers == -1)
@@ -563,9 +564,33 @@ DhcpNameServer 
      if (status != ARES_SUCCESS)

        break;

    }

    fclose(fp);



    if (!channel->lookups) {

      fp = fopen("/etc/nsswitch.conf", "r");

      if (fp) {

        while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)

        {

          if ((p = try_config(line, "hosts:")) && !channel->lookups)

            status = config_lookup(channel, p, "dns", "files");

        }

        fclose(fp);

      }

    }

    if (!channel->lookups) {

      fp = fopen("/etc/host.conf", "r");

      if (fp) {

        while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)

        {

          if ((p = try_config(line, "order")) && !channel->lookups)

            status = config_lookup(channel, p, "bind", "hosts");

        }

        fclose(fp);

      }

    }



    if(line)

      free(line);

    fclose(fp);

  }



#endif
@@ -679,7 +704,8 @@ static int config_domain(ares_channel channel, char *str) 
  return set_search(channel, str);

}



static int config_lookup(ares_channel channel, const char *str)

static int config_lookup(ares_channel channel, const char *str,

                         const char *bindch, const char *filech)

{

  char lookups[3], *l;

  const char *p;
@@ -692,11 +718,13 @@ static int config_lookup(ares_channel channel, const char *str) 
  p = str;

  while (*p)

    {

      if ((*p == 'b' || *p == 'f') && l < lookups + 2)

	*l++ = *p;

      while (*p && !isspace((unsigned char)*p))

      if ((*p == *bindch || *p == *filech) && l < lookups + 2) {

	if (*p == *bindch) *l++ = 'b';

        else *l++ = 'f';

      }

      while (*p && !isspace((unsigned char)*p) && (*p != ','))

	p++;

      while (isspace((unsigned char)*p))

      while (*p && (isspace((unsigned char)*p) || (*p == ',')))

	p++;

    }

  *l = 0;