static int init_by_resolv_conf(ares_channel channel)
{
FILE *fp;
char *line = NULL, *p;
int linesize, status, nservers = 0, nsort = 0;
struct server_state *servers = NULL;
struct apattern *sortlist = NULL;
fp = fopen(PATH_RESOLV_CONF, "r");
if (!fp)
return (errno == ENOENT) ? ARES_SUCCESS : ARES_EFILE;
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
if ((p = try_config(line, "domain")) && channel->ndomains == -1)
status = config_domain(channel, p);
else if ((p = try_config(line, "lookup")) && !channel->lookups)
status = config_lookup(channel, p);
else if ((p = try_config(line, "search")) && channel->ndomains == -1)
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;
}
free(line);
fclose(fp);
/* Handle errors. */
if (status != ARES_EOF)
{
free(servers);
free(sortlist);
return status;
}
/* If we got any name server entries, fill them in. */
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;
}
int ares__get_hostent(FILE *fp, int family, struct hostent **host)
{
char *line = NULL, *p, *q, **alias;
char *txtaddr, *txthost, *txtalias;
int status;
size_t addrlen, linesize, naliases;
struct ares_addr addr;
struct hostent *hostent = NULL;
*host = NULL; /* Assume failure */
/* Validate family */
switch (family) {
case AF_INET:
case AF_INET6:
case AF_UNSPEC:
break;
default:
return ARES_EBADFAMILY;
}
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
/* Trim line comment. */
p = line;
while (*p && (*p != '#'))
p++;
*p = '\0';
/* Trim trailing whitespace. */
q = p - 1;
while ((q >= line) && ISSPACE(*q))
q--;
*++q = '\0';
/* Skip leading whitespace. */
p = line;
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if empty. */
continue;
/* Pointer to start of IPv4 or IPv6 address part. */
txtaddr = p;
/* Advance past address part. */
while (*p && !ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if reached end of line. */
continue;
/* Null terminate address part. */
*p = '\0';
/* Advance to host name */
p++;
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if reached end of line. */
continue;
/* Pointer to start of host name. */
txthost = p;
/* Advance past host name. */
while (*p && !ISSPACE(*p))
p++;
/* Pointer to start of first alias. */
txtalias = NULL;
if (*p)
{
q = p + 1;
while (*q && ISSPACE(*q))
q++;
if (*q)
txtalias = q;
}
/* Null terminate host name. */
*p = '\0';
/* find out number of aliases. */
naliases = 0;
if (txtalias)
{
p = txtalias;
while (*p)
{
while (*p && !ISSPACE(*p))
p++;
while (*p && ISSPACE(*p))
p++;
naliases++;
}
}
/* Convert address string to network address for the requested family. */
addrlen = 0;
addr.family = AF_UNSPEC;
addr.addrV4.s_addr = INADDR_NONE;
if ((family == AF_INET) || (family == AF_UNSPEC))
{
addr.addrV4.s_addr = inet_addr(txtaddr);
if (addr.addrV4.s_addr != INADDR_NONE)
{
/* Actual network address family and length. */
addr.family = AF_INET;
addrlen = sizeof(addr.addrV4);
}
}
if ((family == AF_INET6) || ((family == AF_UNSPEC) && (!addrlen)))
{
if (ares_inet_pton(AF_INET6, txtaddr, &addr.addrV6) > 0)
{
/* Actual network address family and length. */
addr.family = AF_INET6;
addrlen = sizeof(addr.addrV6);
}
}
if (!addrlen)
/* Ignore line if invalid address string for the requested family. */
continue;
/*
** Actual address family possible values are AF_INET and AF_INET6 only.
*/
/* Allocate memory for the hostent structure. */
hostent = malloc(sizeof(struct hostent));
if (!hostent)
break;
/* Initialize fields for out of memory condition. */
hostent->h_aliases = NULL;
hostent->h_addr_list = NULL;
/* Copy official host name. */
hostent->h_name = strdup(txthost);
if (!hostent->h_name)
break;
/* Copy network address. */
hostent->h_addr_list = malloc(2 * sizeof(char *));
if (!hostent->h_addr_list)
break;
hostent->h_addr_list[1] = NULL;
hostent->h_addr_list[0] = malloc(addrlen);
if (!hostent->h_addr_list[0])
break;
if (addr.family == AF_INET)
memcpy(hostent->h_addr_list[0], &addr.addrV4, sizeof(addr.addrV4));
else
memcpy(hostent->h_addr_list[0], &addr.addrV6, sizeof(addr.addrV6));
/* Copy aliases. */
hostent->h_aliases = malloc((naliases + 1) * sizeof(char *));
if (!hostent->h_aliases)
break;
alias = hostent->h_aliases;
while (naliases)
*(alias + naliases--) = NULL;
*alias = NULL;
while (txtalias)
{
p = txtalias;
while (*p && !ISSPACE(*p))
p++;
q = p;
while (*q && ISSPACE(*q))
q++;
*p = '\0';
if ((*alias = strdup(txtalias)) == NULL)
break;
alias++;
txtalias = *q ? q : NULL;
}
if (txtalias)
/* Alias memory allocation failure. */
break;
/* Copy actual network address family and length. */
hostent->h_addrtype = addr.family;
hostent->h_length = (int)addrlen;
/* Free line buffer. */
free(line);
/* Return hostent successfully */
*host = hostent;
return ARES_SUCCESS;
}
/* If allocated, free line buffer. */
if (line)
free(line);
if (status == ARES_SUCCESS)
{
/* Memory allocation failure; clean up. */
if (hostent)
{
if (hostent->h_name)
free((char *) hostent->h_name);
if (hostent->h_aliases)
{
for (alias = hostent->h_aliases; *alias; alias++)
free(*alias);
free(hostent->h_aliases);
}
if (hostent->h_addr_list)
{
if (hostent->h_addr_list[0])
free(hostent->h_addr_list[0]);
free(hostent->h_addr_list);
}
free(hostent);
}
return ARES_ENOMEM;
}
return status;
}
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;
}
/* Determine if this name only yields one query. If it does, set *s to
* the string we should query, in an allocated buffer. If not, set *s
* to NULL.
*/
static int single_domain(ares_channel channel, const char *name, char **s)
{
size_t len = strlen(name);
const char *hostaliases;
FILE *fp;
char *line = NULL;
int linesize, status;
const char *p, *q;
/* If the name contains a trailing dot, then the single query is the name
* sans the trailing dot.
*/
if (name[len - 1] == '.')
{
*s = strdup(name);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
if (!(channel->flags & ARES_FLAG_NOALIASES) && !strchr(name, '.'))
{
/* The name might be a host alias. */
#ifdef UNDER_CE
hostaliases = NULL;
#else
hostaliases = getenv("HOSTALIASES");
#endif
if (hostaliases)
{
fp = fopen(hostaliases, "r");
if (fp)
{
while ((status = ares__read_line(fp, &line, &linesize))
== ARES_SUCCESS)
{
if (strncasecmp(line, name, len) != 0 ||
!isspace((unsigned char)line[len]))
continue;
p = line + len;
while (isspace((unsigned char)*p))
p++;
if (*p)
{
q = p + 1;
while (*q && !isspace((unsigned char)*q))
q++;
*s = malloc(q - p + 1);
if (*s)
{
memcpy(*s, p, q - p);
(*s)[q - p] = 0;
}
free(line);
fclose(fp);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
}
free(line);
fclose(fp);
if (status != ARES_SUCCESS)
return status;
}
}
}
if (channel->flags & ARES_FLAG_NOSEARCH || channel->ndomains == 0)
{
/* No domain search to do; just try the name as-is. */
*s = strdup(name);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
*s = NULL;
return ARES_SUCCESS;
}
/* Determine if this name only yields one query. If it does, set *s to
* the string we should query, in an allocated buffer. If not, set *s
* to NULL.
*/
static int single_domain(ares_channel channel, const char *name, char **s)
{
size_t len = strlen(name);
const char *hostaliases;
FILE *fp;
char *line = NULL;
int status;
size_t linesize;
const char *p, *q;
int error;
/* If the name contains a trailing dot, then the single query is the name
* sans the trailing dot.
*/
if (name[len - 1] == '.')
{
*s = strdup(name);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
if (!(channel->flags & ARES_FLAG_NOALIASES) && !strchr(name, '.'))
{
/* The name might be a host alias. */
hostaliases = getenv("HOSTALIASES");
if (hostaliases)
{
fp = fopen(hostaliases, "r");
if (fp)
{
while ((status = ares__read_line(fp, &line, &linesize))
== ARES_SUCCESS)
{
if (strncasecmp(line, name, len) != 0 ||
!ISSPACE(line[len]))
continue;
p = line + len;
while (ISSPACE(*p))
p++;
if (*p)
{
q = p + 1;
while (*q && !ISSPACE(*q))
q++;
*s = malloc(q - p + 1);
if (*s)
{
memcpy(*s, p, q - p);
(*s)[q - p] = 0;
}
free(line);
fclose(fp);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
}
free(line);
fclose(fp);
if (status != ARES_SUCCESS)
return status;
}
else
{
error = errno;
switch(error)
{
case ENOENT:
case ESRCH:
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n",
hostaliases));
*s = NULL;
return ARES_EFILE;
}
}
}
}
if (channel->flags & ARES_FLAG_NOSEARCH || channel->ndomains == 0)
{
/* No domain search to do; just try the name as-is. */
*s = strdup(name);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
*s = NULL;
return ARES_SUCCESS;
}
