unix,win: make uv_interface_addresses() consistent

This commit does a few things to make the function more
consistent across platforms:

- Initialize the output parameters before everything else.
- Return early if there are no interfaces instead of performing
  zero-sized allocations.
- Add a missing memory deallocation.

Refs: https://github.com/libuv/libuv/pull/2035
PR-URL: https://github.com/libuv/libuv/pull/2039
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

src/unix/aix-common.c

@@ -175,6 +175,7 @@ int uv_interface_addresses(uv_interface_address_t** addresses,
   struct sockaddr_dl* sa_addr;
 
   *count = 0;
+  *addresses = NULL;
 
   if (0 > (sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP))) {
     return UV__ERR(errno);
@@ -217,6 +218,11 @@ int uv_interface_addresses(uv_interface_address_t** addresses,
     (*count)++;
   }
 
+  if (*count == 0) {
+    uv__close(sockfd);
+    return 0;
+  }
+
   /* Alloc the return interface structs */
   *addresses = uv__malloc(*count * sizeof(uv_interface_address_t));
   if (!(*addresses)) {
@@ -289,4 +295,4 @@ void uv_free_interface_addresses(uv_interface_address_t* addresses,
   }
 
   uv__free(addresses);
-}
+}

src/unix/bsd-ifaddrs.c

@@ -69,11 +69,12 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
   uv_interface_address_t* address;
   int i;
 
+  *count = 0;
+  *addresses = NULL;
+
   if (getifaddrs(&addrs) != 0)
     return UV__ERR(errno);
 
-  *count = 0;
-
   /* Count the number of interfaces */
   for (ent = addrs; ent != NULL; ent = ent->ifa_next) {
     if (uv__ifaddr_exclude(ent, UV__EXCLUDE_IFADDR))
@@ -81,6 +82,11 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
     (*count)++;
   }
 
+  if (*count == 0) {
+    freeifaddrs(addrs);
+    return 0;
+  }
+
   *addresses = uv__malloc(*count * sizeof(**addresses));
 
   if (*addresses == NULL) {

src/unix/linux-core.c

@@ -829,6 +829,8 @@ static int uv__ifaddr_exclude(struct ifaddrs *ent, int exclude_type) {
 int uv_interface_addresses(uv_interface_address_t** addresses,
   int* count) {
 #ifndef HAVE_IFADDRS_H
+  *count = 0;
+  *addresses = NULL;
   return UV_ENOSYS;
 #else
   struct ifaddrs *addrs, *ent;
@@ -836,12 +838,12 @@ int uv_interface_addresses(uv_interface_address_t** addresses,
   int i;
   struct sockaddr_ll *sll;
 
-  if (getifaddrs(&addrs))
-    return UV__ERR(errno);
-
   *count = 0;
   *addresses = NULL;
 
+  if (getifaddrs(&addrs))
+    return UV__ERR(errno);
+
   /* Count the number of interfaces */
   for (ent = addrs; ent != NULL; ent = ent->ifa_next) {
     if (uv__ifaddr_exclude(ent, UV__EXCLUDE_IFADDR))
@@ -850,8 +852,10 @@ int uv_interface_addresses(uv_interface_address_t** addresses,
     (*count)++;
   }
 
-  if (*count == 0)
+  if (*count == 0) {
+    freeifaddrs(addrs);
     return 0;
+  }
 
   *addresses = uv__malloc(*count * sizeof(**addresses));
   if (!(*addresses)) {

src/unix/os390.c

@@ -529,12 +529,14 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
   struct ifreq* p;
   int count_v6;
 
+  *count = 0;
+  *addresses = NULL;
+
   /* get the ipv6 addresses first */
   uv_interface_address_t* addresses_v6;
   uv__interface_addresses_v6(&addresses_v6, &count_v6);
 
   /* now get the ipv4 addresses */
-  *count = 0;
 
   /* Assume maximum buffer size allowable */
   maxsize = 16384;
@@ -576,6 +578,11 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
     (*count)++;
   }
 
+  if (*count == 0) {
+    uv__close(sockfd);
+    return 0;
+  }
+
   /* Alloc the return interface structs */
   *addresses = uv__malloc((*count + count_v6) *
                           sizeof(uv_interface_address_t));
@@ -750,7 +757,7 @@ int uv_fs_event_stop(uv_fs_event_t* handle) {
   memcpy(reg_struct.__rfis_rftok, handle->rfis_rftok,
          sizeof(handle->rfis_rftok));
 
-  /* 
+  /*
    * This call will take "/" as the path argument in case we
    * don't care to supply the correct path. The system will simply
    * ignore it.
@@ -986,7 +993,7 @@ void uv__set_process_title(const char* title) {
 }
 
 int uv__io_fork(uv_loop_t* loop) {
-  /* 
+  /*
     Nullify the msg queue but don't close it because
     it is still being used by the parent.
   */

src/unix/sunos.c

@@ -692,6 +692,8 @@ void uv_free_cpu_info(uv_cpu_info_t* cpu_infos, int count) {
 
 #ifdef SUNOS_NO_IFADDRS
 int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
+  *count = 0;
+  *addresses = NULL;
   return UV_ENOSYS;
 }
 #else  /* SUNOS_NO_IFADDRS */
@@ -758,11 +760,12 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
   struct ifaddrs* addrs;
   struct ifaddrs* ent;
 
+  *count = 0;
+  *addresses = NULL;
+
   if (getifaddrs(&addrs))
     return UV__ERR(errno);
 
-  *count = 0;
-
   /* Count the number of interfaces */
   for (ent = addrs; ent != NULL; ent = ent->ifa_next) {
     if (uv__ifaddr_exclude(ent))
@@ -770,6 +773,11 @@ int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
     (*count)++;
   }
 
+  if (*count == 0) {
+    freeifaddrs(addrs);
+    return 0;
+  }
+
   *addresses = uv__malloc(*count * sizeof(**addresses));
   if (!(*addresses)) {
     freeifaddrs(addrs);

src/win/util.c

@@ -816,6 +816,9 @@ int uv_interface_addresses(uv_interface_address_t** addresses_ptr,
   int is_vista_or_greater;
   ULONG flags;
 
+  *addresses_ptr = NULL;
+  *count_ptr = 0;
+
   is_vista_or_greater = is_windows_version_or_greater(6, 0, 0, 0);
   if (is_vista_or_greater) {
     flags = GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST |