Revert "dns cache per interface iteration 2"

This reverts commit f1464ff95670e6dcc0e12bf9fbbeb4c0346434c9

Change-Id: I3496b9a8cb54614fe3eea016d1391c8a89f3db38
diff --git a/libc/netbsd/resolv/res_cache.c b/libc/netbsd/resolv/res_cache.c
index 23f5c24..afc9a36 100644
--- a/libc/netbsd/resolv/res_cache.c
+++ b/libc/netbsd/resolv/res_cache.c
@@ -43,7 +43,6 @@
 #include <arpa/inet.h>
 #include "resolv_private.h"
 #include "resolv_iface.h"
-#include "res_private.h"
 
 /* This code implements a small and *simple* DNS resolver cache.
  *
@@ -1250,16 +1249,9 @@
     struct resolv_cache_info*   next;
     char*                       nameservers[MAXNS +1];
     struct addrinfo*            nsaddrinfo[MAXNS + 1];
-    char                        defdname[256];
-    int                         dnsrch_offset[MAXDNSRCH+1];  // offsets into defdname
+    char*                       domains;
 } CacheInfo;
 
-typedef struct resolv_pidiface_info {
-    int                             pid;
-    char                            ifname[IF_NAMESIZE + 1];
-    struct resolv_pidiface_info*    next;
-} PidIfaceInfo;
-
 #define  HTABLE_VALID(x)  ((x) != NULL && (x) != HTABLE_DELETED)
 
 static void
@@ -1312,7 +1304,6 @@
             }
         } else {
             struct timespec ts = {0,0};
-            XLOG("Waiting for previous request");
             ts.tv_sec = _time_now() + PENDING_REQUEST_TIMEOUT;
             pthread_cond_timedwait(&ri->cond, &cache->lock, &ts);
         }
@@ -1408,8 +1399,9 @@
     if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
         // Don't use the cache in local mode.  This is used by the
         // proxy itself.
-        XLOG("setup cache for non-cache process. size=0, %s", cache_mode);
-        return 0;
+        // TODO - change this to 0 when all dns stuff uses proxy (5918973)
+        XLOG("setup cache for non-cache process. size=1");
+        return 1;
     }
 
     if (__system_property_get(DNS_CACHE_SIZE_PROP_NAME, cache_size) > 0) {
@@ -1548,7 +1540,7 @@
 
         pnode = &node->hlink;
     }
-    return pnode;
+    return pnode; 
 }
 
 /* Add a new entry to the hash table. 'lookup' must be the
@@ -1789,28 +1781,20 @@
 /****************************************************************************/
 /****************************************************************************/
 
-static pthread_once_t        _res_cache_once = PTHREAD_ONCE_INIT;
+static pthread_once_t        _res_cache_once;
 
 // Head of the list of caches.  Protected by _res_cache_list_lock.
 static struct resolv_cache_info _res_cache_list;
 
-// List of pid iface pairs
-static struct resolv_pidiface_info _res_pidiface_list;
-
 // name of the current default inteface
 static char            _res_default_ifname[IF_NAMESIZE + 1];
 
 // lock protecting everything in the _resolve_cache_info structs (next ptr, etc)
 static pthread_mutex_t _res_cache_list_lock;
 
-// lock protecting the _res_pid_iface_list
-static pthread_mutex_t _res_pidiface_list_lock;
 
 /* lookup the default interface name */
 static char *_get_default_iface_locked();
-/* find the first cache that has an associated interface and return the name of the interface */
-static char* _find_any_iface_name_locked( void );
-
 /* insert resolv_cache_info into the list of resolv_cache_infos */
 static void _insert_cache_info_locked(struct resolv_cache_info* cache_info);
 /* creates a resolv_cache_info */
@@ -1831,14 +1815,8 @@
 static struct addrinfo* _get_nameserver_addr_locked(const char* ifname, int n);
 /* lookup the inteface's address */
 static struct in_addr* _get_addr_locked(const char * ifname);
-/* return 1 if the provided list of name servers differs from the list of name servers
- * currently attached to the provided cache_info */
-static int _resolv_is_nameservers_equal_locked(struct resolv_cache_info* cache_info,
-        char** servers, int numservers);
-/* remove a resolv_pidiface_info structure from _res_pidiface_list */
-static void _remove_pidiface_info_locked(int pid);
-/* get a resolv_pidiface_info structure from _res_pidiface_list with a certain pid */
-static struct resolv_pidiface_info* _get_pid_iface_info_locked(int pid);
+
+
 
 static void
 _res_cache_init(void)
@@ -1852,36 +1830,37 @@
 
     memset(&_res_default_ifname, 0, sizeof(_res_default_ifname));
     memset(&_res_cache_list, 0, sizeof(_res_cache_list));
-    memset(&_res_pidiface_list, 0, sizeof(_res_pidiface_list));
     pthread_mutex_init(&_res_cache_list_lock, NULL);
-    pthread_mutex_init(&_res_pidiface_list_lock, NULL);
 }
 
 struct resolv_cache*
-__get_res_cache(const char* ifname)
+__get_res_cache(void)
 {
     struct resolv_cache *cache;
 
     pthread_once(&_res_cache_once, _res_cache_init);
+
     pthread_mutex_lock(&_res_cache_list_lock);
 
-    char* iface;
-    if (ifname == NULL || ifname[0] == '\0') {
-        iface = _get_default_iface_locked();
-        if (iface[0] == '\0') {
-            char* tmp = _find_any_iface_name_locked();
-            if (tmp) {
-                iface = tmp;
-            }
-        }
-    } else {
-        iface = (char *) ifname;
-    }
+    char* ifname = _get_default_iface_locked();
 
-    cache = _get_res_cache_for_iface_locked(iface);
+    // if default interface not set then use the first cache
+    // associated with an interface as the default one.
+    if (ifname[0] == '\0') {
+        struct resolv_cache_info* cache_info = _res_cache_list.next;
+        while (cache_info) {
+            if (cache_info->ifname[0] != '\0') {
+                ifname = cache_info->ifname;
+                break;
+            }
+
+            cache_info = cache_info->next;
+        }
+    }
+    cache = _get_res_cache_for_iface_locked(ifname);
 
     pthread_mutex_unlock(&_res_cache_list_lock);
-    XLOG("_get_res_cache: iface = %s, cache=%p\n", iface, cache);
+    XLOG("_get_res_cache. default_ifname = %s\n", ifname);
     return cache;
 }
 
@@ -2037,29 +2016,11 @@
 static char*
 _get_default_iface_locked(void)
 {
-
     char* iface = _res_default_ifname;
 
     return iface;
 }
 
-static char*
-_find_any_iface_name_locked( void ) {
-    char* ifname = NULL;
-
-    struct resolv_cache_info* cache_info = _res_cache_list.next;
-    while (cache_info) {
-        if (cache_info->ifname[0] != '\0') {
-            ifname = cache_info->ifname;
-            break;
-        }
-
-        cache_info = cache_info->next;
-    }
-
-    return ifname;
-}
-
 void
 _resolv_set_default_iface(const char* ifname)
 {
@@ -2083,19 +2044,16 @@
     int i, rt, index;
     struct addrinfo hints;
     char sbuf[NI_MAXSERV];
-    register char *cp;
-    int *offset;
 
     pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_cache_list_lock);
 
+    pthread_mutex_lock(&_res_cache_list_lock);
     // creates the cache if not created
     _get_res_cache_for_iface_locked(ifname);
 
     struct resolv_cache_info* cache_info = _find_cache_info_locked(ifname);
 
-    if (cache_info != NULL &&
-            !_resolv_is_nameservers_equal_locked(cache_info, servers, numservers)) {
+    if (cache_info != NULL) {
         // free current before adding new
         _free_nameservers_locked(cache_info);
 
@@ -2111,68 +2069,15 @@
             if (rt == 0) {
                 cache_info->nameservers[index] = strdup(servers[i]);
                 index++;
-                XLOG("_resolv_set_nameservers_for_iface: iface = %s, addr = %s\n",
-                        ifname, servers[i]);
             } else {
                 cache_info->nsaddrinfo[index] = NULL;
             }
         }
-
-        // code moved from res_init.c, load_domain_search_list
-        strlcpy(cache_info->defdname, domains, sizeof(cache_info->defdname));
-        if ((cp = strchr(cache_info->defdname, '\n')) != NULL)
-            *cp = '\0';
-        cp = cache_info->defdname;
-        offset = cache_info->dnsrch_offset;
-        while (offset < cache_info->dnsrch_offset + MAXDNSRCH) {
-            while (*cp == ' ' || *cp == '\t') /* skip leading white space */
-                cp++;
-            if (*cp == '\0') /* stop if nothing more to do */
-                break;
-            *offset++ = cp - cache_info->defdname; /* record this search domain */
-            while (*cp) { /* zero-terminate it */
-                if (*cp == ' '|| *cp == '\t') {
-                    *cp++ = '\0';
-                    break;
-                }
-                cp++;
-            }
-        }
-        *offset = -1; /* cache_info->dnsrch_offset has MAXDNSRCH+1 items */
-
-        // flush cache since new settings
-        _flush_cache_for_iface_locked(ifname);
-
+        cache_info->domains = strdup(domains);
     }
-
     pthread_mutex_unlock(&_res_cache_list_lock);
 }
 
-static int
-_resolv_is_nameservers_equal_locked(struct resolv_cache_info* cache_info,
-        char** servers, int numservers)
-{
-    int i;
-    char** ns;
-    int equal = 1;
-
-    // compare each name server against current name servers
-    if (numservers > MAXNS) numservers = MAXNS;
-    for (i = 0; i < numservers && equal; i++) {
-        ns = cache_info->nameservers;
-        equal = 0;
-        while(*ns) {
-            if (strcmp(*ns, servers[i]) == 0) {
-                equal = 1;
-                break;
-            }
-            ns++;
-        }
-    }
-
-    return equal;
-}
-
 static void
 _free_nameservers_locked(struct resolv_cache_info* cache_info)
 {
@@ -2315,192 +2220,3 @@
     }
     return NULL;
 }
-
-static void
-_remove_pidiface_info_locked(int pid) {
-    struct resolv_pidiface_info* result = &_res_pidiface_list;
-    struct resolv_pidiface_info* prev = NULL;
-
-    while (result != NULL && result->pid != pid) {
-        prev = result;
-        result = result->next;
-    }
-    if (prev != NULL && result != NULL) {
-        prev->next = result->next;
-        free(result);
-    }
-}
-
-static struct resolv_pidiface_info*
-_get_pid_iface_info_locked(int pid)
-{
-    struct resolv_pidiface_info* result = &_res_pidiface_list;
-    while (result != NULL && result->pid != pid) {
-        result = result->next;
-    }
-
-    return result;
-}
-
-void
-_resolv_set_iface_for_pid(const char* ifname, int pid)
-{
-    // make sure the pid iface list is created
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_pidiface_list_lock);
-
-    struct resolv_pidiface_info* pidiface_info = _get_pid_iface_info_locked(pid);
-    if (!pidiface_info) {
-        pidiface_info = calloc(sizeof(*pidiface_info), 1);
-        if (pidiface_info) {
-            pidiface_info->pid = pid;
-            int len = sizeof(pidiface_info->ifname);
-            strncpy(pidiface_info->ifname, ifname, len - 1);
-            pidiface_info->ifname[len - 1] = '\0';
-
-            pidiface_info->next = _res_pidiface_list.next;
-            _res_pidiface_list.next = pidiface_info;
-
-            XLOG("_resolv_set_iface_for_pid: pid %d , iface %s\n", pid, ifname);
-        } else {
-            XLOG("_resolv_set_iface_for_pid failing calloc");
-        }
-    }
-
-    pthread_mutex_unlock(&_res_pidiface_list_lock);
-}
-
-void
-_resolv_clear_iface_for_pid(int pid)
-{
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_pidiface_list_lock);
-
-    _remove_pidiface_info_locked(pid);
-
-    XLOG("_resolv_clear_iface_for_pid: pid %d\n", pid);
-
-    pthread_mutex_unlock(&_res_pidiface_list_lock);
-}
-
-int
-_resolv_get_pids_associated_interface(int pid, char* buff, int buffLen)
-{
-    int len = 0;
-
-    if (!buff) {
-        return -1;
-    }
-
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_pidiface_list_lock);
-
-    struct resolv_pidiface_info* pidiface_info = _get_pid_iface_info_locked(pid);
-    buff[0] = '\0';
-    if (pidiface_info) {
-        len = strlen(pidiface_info->ifname);
-        if (len < buffLen) {
-            strncpy(buff, pidiface_info->ifname, len);
-            buff[len] = '\0';
-        }
-    }
-
-    XLOG("_resolv_get_pids_associated_interface buff: %s\n", buff);
-
-    pthread_mutex_unlock(&_res_pidiface_list_lock);
-
-    return len;
-}
-
-int
-_resolv_get_default_iface(char* buff, int buffLen)
-{
-    char* ifname;
-    int len = 0;
-
-    if (!buff || buffLen == 0) {
-        return -1;
-    }
-
-    pthread_once(&_res_cache_once, _res_cache_init);
-    pthread_mutex_lock(&_res_cache_list_lock);
-
-    ifname = _get_default_iface_locked();
-
-    // if default interface not set. Get first cache with an interface
-    if (ifname[0] == '\0') {
-        ifname = _find_any_iface_name_locked();
-    }
-
-    if (ifname) {
-        len = strlen(ifname);
-        if (len < buffLen) {
-            strncpy(buff, ifname, len);
-            buff[len] = '\0';
-        }
-    } else {
-        buff[0] = '\0';
-    }
-
-    pthread_mutex_unlock(&_res_cache_list_lock);
-
-    return len;
-}
-
-int
-_resolv_populate_res_for_iface(res_state statp)
-{
-    int nserv;
-    struct resolv_cache_info* info = NULL;
-
-    if (statp) {
-        struct addrinfo* ai;
-
-        if (statp->iface[0] == '\0') { // no interface set assign default
-            _resolv_get_default_iface(statp->iface, sizeof(statp->iface));
-        }
-
-        pthread_once(&_res_cache_once, _res_cache_init);
-        pthread_mutex_lock(&_res_cache_list_lock);
-        info = _find_cache_info_locked(statp->iface);
-
-        if (info == NULL) return 0;
-
-        XLOG("_resolv_populate_res_for_iface: %s\n", statp->iface);
-        for (nserv = 0; nserv < MAXNS; nserv++) {
-            ai = info->nsaddrinfo[nserv];
-            if (ai == NULL) {
-                break;
-            }
-
-            if ((size_t) ai->ai_addrlen <= sizeof(statp->_u._ext.ext->nsaddrs[0])) {
-                if (statp->_u._ext.ext != NULL) {
-                    memcpy(&statp->_u._ext.ext->nsaddrs[nserv], ai->ai_addr, ai->ai_addrlen);
-                    statp->nsaddr_list[nserv].sin_family = AF_UNSPEC;
-                } else {
-                    if ((size_t) ai->ai_addrlen
-                            <= sizeof(statp->nsaddr_list[0])) {
-                        memcpy(&statp->nsaddr_list[nserv], ai->ai_addr,
-                                ai->ai_addrlen);
-                    } else {
-                        statp->nsaddr_list[nserv].sin_family = AF_UNSPEC;
-                    }
-                }
-            } else {
-                XLOG("_resolv_populate_res_for_iface found too long addrlen");
-            }
-        }
-        statp->nscount = nserv;
-        // now do search domains.  Note that we cache the offsets as this code runs alot
-        // but the setting/offset-computer only runs when set/changed
-        strlcpy(statp->defdname, info->defdname, sizeof(statp->defdname));
-        register char **pp = statp->dnsrch;
-        register int *p = info->dnsrch_offset;
-        while (pp < statp->dnsrch + MAXDNSRCH && *p != -1) {
-            *pp++ = &statp->defdname + *p++;
-        }
-
-        pthread_mutex_unlock(&_res_cache_list_lock);
-    }
-    return nserv;
-}