- 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.
This commit is contained in:
Daniel Stenberg 2004-09-26 22:35:18 +00:00
parent 12dc142a28
commit 3451e888b9
2 changed files with 50 additions and 8 deletions

View File

@ -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,

View File

@ -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;