static int init_by_resolv_conf(ares_channel channel)
{
#ifndef WATT32
char *line = NULL;
#endif
int status = -1, nservers = 0, nsort = 0;
struct server_state *servers = NULL;
struct apattern *sortlist = NULL;
#ifdef WIN32
/*
NameServer info via IPHLPAPI (IP helper API):
GetNetworkParams() should be the trusted source for this.
Available in Win-98/2000 and later. If that fail, fall-back to
registry information.
NameServer Registry:
On Windows 9X, the DNS server can be found in:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP\NameServer
On Windows NT/2000/XP/2003:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\NameServer
or
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DhcpNameServer
or
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\{AdapterID}\
NameServer
or
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\{AdapterID}\
DhcpNameServer
*/
HKEY mykey;
HKEY subkey;
DWORD data_type;
DWORD bytes;
DWORD result;
char buf[512];
win_platform platform;
if (channel->nservers > -1) /* don't override ARES_OPT_SERVER */
return ARES_SUCCESS;
if (get_iphlpapi_dns_info(buf,sizeof(buf)) > 0)
{
status = config_nameserver(&servers, &nservers, buf);
if (status == ARES_SUCCESS)
goto okay;
}
platform = ares__getplatform();
if (platform == WIN_NT)
{
if (RegOpenKeyEx(
HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
KEY_READ, &mykey
) == ERROR_SUCCESS)
{
RegOpenKeyEx(mykey, "Interfaces", 0,
KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS, &subkey);
if (get_res_nt(mykey, NAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
else if (get_res_nt(mykey, DHCPNAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
/* Try the interfaces */
else if (get_res_interfaces_nt(subkey, NAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
else if (get_res_interfaces_nt(subkey, DHCPNAMESERVER, &line))
{
status = config_nameserver(&servers, &nservers, line);
free(line);
}
RegCloseKey(subkey);
RegCloseKey(mykey);
}
}
else if (platform == WIN_9X)
{
if (RegOpenKeyEx(
HKEY_LOCAL_MACHINE, WIN_NS_9X, 0,
KEY_READ, &mykey
) == ERROR_SUCCESS)
{
if ((result = RegQueryValueEx(
mykey, NAMESERVER, NULL, &data_type,
NULL, &bytes
)
) == ERROR_SUCCESS ||
result == ERROR_MORE_DATA)
{
if (bytes)
{
line = malloc(bytes+1);
if (RegQueryValueEx(mykey, NAMESERVER, NULL, &data_type,
(unsigned char *)line, &bytes) ==
ERROR_SUCCESS)
{
status = config_nameserver(&servers, &nservers, line);
}
free(line);
}
}
}
RegCloseKey(mykey);
}
if (status == ARES_SUCCESS)
status = ARES_EOF;
else
/* Catch the case when all the above checks fail (which happens when there
is no network card or the cable is unplugged) */
status = ARES_EFILE;
#elif defined(__riscos__)
/* Under RISC OS, name servers are listed in the
system variable Inet$Resolvers, space separated. */
line = getenv("Inet$Resolvers");
status = ARES_EOF;
if (line) {
char *resolvers = strdup(line), *pos, *space;
if (!resolvers)
return ARES_ENOMEM;
pos = resolvers;
do {
space = strchr(pos, ' ');
if (space)
*space = '\0';
status = config_nameserver(&servers, &nservers, pos);
if (status != ARES_SUCCESS)
break;
pos = space + 1;
} while (space);
if (status == ARES_SUCCESS)
status = ARES_EOF;
free(resolvers);
}
#elif defined(WATT32)
int i;
sock_init();
for (i = 0; def_nameservers[i]; i++)
;
if (i == 0)
return ARES_SUCCESS; /* use localhost DNS server */
nservers = i;
servers = calloc(i, sizeof(struct server_state));
if (!servers)
return ARES_ENOMEM;
for (i = 0; def_nameservers[i]; i++)
{
servers[i].addr.addrV4.s_addr = htonl(def_nameservers[i]);
servers[i].addr.family = AF_INET;
}
status = ARES_EOF;
#elif defined(ANDROID)
char value[PROP_VALUE_MAX]="";
__system_property_get("net.dns1", value);
status = config_nameserver(&servers, &nservers, value);
if (status == ARES_SUCCESS)
status = ARES_EOF;
#else
{
char *p;
FILE *fp;
size_t linesize;
int error;
/* Don't read resolv.conf and friends if we don't have to */
if (ARES_CONFIG_CHECK(channel))
return ARES_SUCCESS;
fp = fopen(PATH_RESOLV_CONF, "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
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, "bind", "file");
else if ((p = try_config(line, "search", ';')))
status = set_search(channel, p);
else if ((p = try_config(line, "nameserver", ';')) &&
channel->nservers == -1)
status = config_nameserver(&servers, &nservers, p);
else if ((p = try_config(line, "sortlist", ';')) &&
channel->nsort == -1)
status = config_sortlist(&sortlist, &nsort, p);
else if ((p = try_config(line, "options", ';')))
status = set_options(channel, p);
else
status = ARES_SUCCESS;
if (status != ARES_SUCCESS)
break;
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", PATH_RESOLV_CONF));
status = ARES_EFILE;
}
}
if ((status == ARES_EOF) && (!channel->lookups)) {
/* Many systems (Solaris, Linux, BSD's) use nsswitch.conf */
fp = fopen("/etc/nsswitch.conf", "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "hosts:", '\0')) && !channel->lookups)
/* ignore errors */
(void)config_lookup(channel, p, "dns", "files");
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", "/etc/nsswitch.conf"));
status = ARES_EFILE;
}
}
}
if ((status == ARES_EOF) && (!channel->lookups)) {
/* Linux / GNU libc 2.x and possibly others have host.conf */
fp = fopen("/etc/host.conf", "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "order", '\0')) && !channel->lookups)
/* ignore errors */
(void)config_lookup(channel, p, "bind", "hosts");
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", "/etc/host.conf"));
status = ARES_EFILE;
}
}
}
if ((status == ARES_EOF) && (!channel->lookups)) {
/* Tru64 uses /etc/svc.conf */
fp = fopen("/etc/svc.conf", "r");
if (fp) {
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "hosts=", '\0')) && !channel->lookups)
/* ignore errors */
(void)config_lookup(channel, p, "bind", "local");
}
fclose(fp);
}
else {
error = ERRNO;
switch(error) {
case ENOENT:
case ESRCH:
status = ARES_EOF;
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n", "/etc/svc.conf"));
status = ARES_EFILE;
}
}
}
if(line)
free(line);
}
#endif
/* Handle errors. */
if (status != ARES_EOF)
{
if (servers != NULL)
free(servers);
if (sortlist != NULL)
free(sortlist);
return status;
}
/* If we got any name server entries, fill them in. */
#ifdef WIN32
okay:
#endif
if (servers)
{
channel->servers = servers;
channel->nservers = nservers;
}
/* If we got any sortlist entries, fill them in. */
if (sortlist)
{
channel->sortlist = sortlist;
channel->nsort = nsort;
}
return ARES_SUCCESS;
}
static int file_lookup(const char *name, int family, struct hostent **host)
{
FILE *fp;
char **alias;
int status;
int error;
#ifdef WIN32
char PATH_HOSTS[MAX_PATH];
win_platform platform;
PATH_HOSTS[0] = '\0';
platform = ares__getplatform();
if (platform == WIN_NT) {
char tmp[MAX_PATH];
HKEY hkeyHosts;
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
&hkeyHosts) == ERROR_SUCCESS)
{
DWORD dwLength = MAX_PATH;
RegQueryValueEx(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
&dwLength);
ExpandEnvironmentStrings(tmp, PATH_HOSTS, MAX_PATH);
RegCloseKey(hkeyHosts);
}
}
else if (platform == WIN_9X)
GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
else
return ARES_ENOTFOUND;
strcat(PATH_HOSTS, WIN_PATH_HOSTS);
#elif defined(WATT32)
extern const char *_w32_GetHostsFile (void);
const char *PATH_HOSTS = _w32_GetHostsFile();
if (!PATH_HOSTS)
return ARES_ENOTFOUND;
#endif
fp = fopen(PATH_HOSTS, "r");
if (!fp)
{
error = ERRNO;
switch(error)
{
case ENOENT:
case ESRCH:
return ARES_ENOTFOUND;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n",
PATH_HOSTS));
*host = NULL;
return ARES_EFILE;
}
}
while ((status = ares__get_hostent(fp, family, host)) == ARES_SUCCESS)
{
if (strcasecmp((*host)->h_name, name) == 0)
break;
for (alias = (*host)->h_aliases; *alias; alias++)
{
if (strcasecmp(*alias, name) == 0)
break;
}
if (*alias)
break;
ares_free_hostent(*host);
}
fclose(fp);
if (status == ARES_EOF)
status = ARES_ENOTFOUND;
if (status != ARES_SUCCESS)
*host = NULL;
return status;
}
