Merge pull request #1974 from RaimoNiskanen/raimo/getifaddrs-netns/ERIERL-189/OTP-15121

Implement {netns,NS} option for inet:getifaddrs/1 and friends

3 files changed, 156 insertions, 47 deletions

diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index 7f20477363..6d1c5cf6cc 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -5178,6 +5178,71 @@ static int hwaddr_libdlpi_lookup(const char *ifnm,
 }
 #endif
 
+#ifdef HAVE_GETIFADDRS
+/* Returns 0 for success and errno() for failure */
+static int call_getifaddrs(inet_descriptor* desc_p, struct ifaddrs **ifa_pp)
+{
+    int result, save_errno;
+#ifdef HAVE_SETNS
+    int current_ns;
+
+    current_ns = 0;
+    if (desc_p->netns != NULL) {
+        int new_ns;
+	/* Temporarily change network namespace for this thread
+	 * over the getifaddrs() call
+	 */
+	current_ns = open("/proc/self/ns/net", O_RDONLY);
+	if (current_ns == INVALID_SOCKET)
+	    return sock_errno();
+	new_ns = open(desc_p->netns, O_RDONLY);
+	if (new_ns == INVALID_SOCKET) {
+	    save_errno = sock_errno();
+	    while (close(current_ns) == INVALID_SOCKET &&
+		   sock_errno() == EINTR);
+	    return save_errno;
+	}
+	if (setns(new_ns, CLONE_NEWNET) != 0) {
+	    save_errno = sock_errno();
+	    while (close(new_ns) == INVALID_SOCKET &&
+		   sock_errno() == EINTR);
+	    while (close(current_ns) == INVALID_SOCKET &&
+		   sock_errno() == EINTR);
+	    return save_errno;
+	}
+	else {
+	    while (close(new_ns) == INVALID_SOCKET &&
+		   sock_errno() == EINTR);
+	}
+    }
+#endif
+    save_errno = 0;
+    result = getifaddrs(ifa_pp);
+    if (result  < 0)
+        save_errno = sock_errno();
+#ifdef HAVE_SETNS
+    if (desc_p->netns != NULL) {
+        /* Restore network namespace */
+        if (setns(current_ns, CLONE_NEWNET) != 0) {
+            /* XXX Failed to restore network namespace.
+             * What to do? Tidy up and return an error...
+             * Note that the thread now might still be in the set namespace.
+	     * Can this even happen? Should the emulator be aborted?
+	     */
+            if (result >= 0) {
+                /* We got a result but have to waste it */
+                save_errno = sock_errno();
+                freeifaddrs(*ifa_pp);
+            }
+	}
+        while (close(current_ns) == INVALID_SOCKET &&
+               sock_errno() == EINTR);
+    }
+#endif
+    return save_errno;
+}
+#endif /* #ifdef HAVE_GETIFADDRS */
+
 /* FIXME: temporary hack */
 #ifndef IFHWADDRLEN
 #define IFHWADDRLEN 6
@@ -5255,8 +5320,8 @@ static ErlDrvSSizeT inet_ctl_ifget(inet_descriptor* desc,
 	    struct sockaddr_dl *sdlp;
 	    int found = 0;
 
-	    if (getifaddrs(&ifa) == -1)
-		goto error;
+            if (call_getifaddrs(desc, &ifa) != 0)
+                goto error;
 
 	    for (ifp = ifa; ifp; ifp = ifp->ifa_next) {
 		if ((ifp->ifa_addr->sa_family == AF_LINK) &&
@@ -5974,6 +6039,7 @@ static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
     ErlDrvSizeT buf_size;
     char *buf_p;
     char *buf_alloc_p;
+    int save_errno;
 
     buf_size = GETIFADDRS_BUFSZ;
     buf_alloc_p = ALLOC(GETIFADDRS_BUFSZ);
@@ -6008,9 +6074,9 @@ static ErlDrvSSizeT inet_ctl_getifaddrs(inet_descriptor* desc_p,
 	}                                                               \
     } while (0)
 
-    if (getifaddrs(&ifa_p) < 0) {
-	return ctl_error(sock_errno(), rbuf_pp, rsize);
-    }
+    if ((save_errno = call_getifaddrs(desc_p, &ifa_p)) != 0)
+        return ctl_error(save_errno, rbuf_pp, rsize);
+
     ifa_free_p = ifa_p;
     *buf_p++ = INET_REP_OK;
     for (;  ifa_p;  ifa_p = ifa_p->ifa_next) {
diff --git a/erts/preloaded/ebin/prim_inet.beam b/erts/preloaded/ebin/prim_inet.beam
index 4a345f8152..eebfe19a11 100644
--- a/erts/preloaded/ebin/prim_inet.beam
+++ b/erts/preloaded/ebin/prim_inet.beam
diff --git a/erts/preloaded/src/prim_inet.erl b/erts/preloaded/src/prim_inet.erl
index 8169943dde..1da852deb2 100644
--- a/erts/preloaded/src/prim_inet.erl
+++ b/erts/preloaded/src/prim_inet.erl
@@ -870,9 +870,9 @@ chgopts(S, Opts) when is_port(S), is_list(Opts) ->
 
 getifaddrs(S) when is_port(S) ->
     case ctl_cmd(S, ?INET_REQ_GETIFADDRS, []) of
-	{ok, Data} ->
-	    {ok, comp_ifaddrs(build_ifaddrs(Data), ktree_empty())};
-	{error,enotsup} ->
+        {ok, Data} ->
+            {ok, comp_ifaddrs(build_ifaddrs(Data))};
+        {error,enotsup} ->
 	    case getiflist(S) of
 		{ok, IFs} ->
 		    {ok, getifaddrs_ifget(S, IFs)};
@@ -881,30 +881,75 @@ getifaddrs(S) when is_port(S) ->
 	Err2 -> Err2
     end.
 
-%% Restructure interface properties per interface and remove duplicates
-
-comp_ifaddrs([{If,Opts}|IfOpts], T) ->
-    case ktree_is_defined(If, T) of
-	true ->
-	    OptSet = comp_ifaddrs_add(ktree_get(If, T), Opts),
-	    comp_ifaddrs(IfOpts, ktree_update(If, OptSet, T));
-	false ->
-	    OptSet = comp_ifaddrs_add(ktree_empty(), Opts),
-	    comp_ifaddrs(IfOpts, ktree_insert(If, OptSet, T))
-     end;
-comp_ifaddrs([], T) ->
-    [{If,ktree_keys(ktree_get(If, T))} || If <- ktree_keys(T)].
-
-comp_ifaddrs_add(OptSet, [Opt|Opts]) ->
-    case ktree_is_defined(Opt, OptSet) of
-	true
-	  when element(1, Opt) =:= flags;
-	       element(1, Opt) =:= hwaddr ->
-	    comp_ifaddrs_add(OptSet, Opts);
-	_ ->
-	    comp_ifaddrs_add(ktree_insert(Opt, undefined, OptSet), Opts)
+%% Restructure interface properties per interface
+
+comp_ifaddrs(IfOpts) ->
+    comp_ifaddrs(IfOpts, ktree_empty()).
+%%
+comp_ifaddrs([{If,[{flags,Flags}|Opts]}|IfOpts], IfT) ->
+    case ktree_is_defined(If, IfT) of
+        true ->
+            comp_ifaddrs(
+              IfOpts,
+              ktree_update(
+                If,
+                comp_ifaddrs_flags(Flags, Opts, ktree_get(If, IfT)),
+                IfT));
+        false ->
+            comp_ifaddrs(
+              IfOpts,
+              ktree_insert(
+                If,
+                comp_ifaddrs_flags(Flags, Opts, ktree_empty()),
+                IfT))
     end;
-comp_ifaddrs_add(OptSet, []) -> OptSet.
+comp_ifaddrs([], IfT) ->
+    comp_ifaddrs_2(ktree_keys(IfT), IfT).
+
+comp_ifaddrs_flags(Flags, Opts, FlagsT) ->
+    case ktree_is_defined(Flags, FlagsT) of
+        true ->
+            ktree_update(
+              Flags,
+              rev(Opts, ktree_get(Flags, FlagsT)),
+              FlagsT);
+        false ->
+            ktree_insert(Flags, rev(Opts), FlagsT)
+    end.
+
+comp_ifaddrs_2([If|Ifs], IfT) ->
+    FlagsT = ktree_get(If, IfT),
+    [{If,comp_ifaddrs_3(ktree_keys(FlagsT), FlagsT)}
+     | comp_ifaddrs_2(Ifs, IfT)];
+comp_ifaddrs_2([], _IfT) ->
+    [].
+%%
+comp_ifaddrs_3([Flags|FlagsL], FlagsT) ->
+    [{flags,Flags}|hwaddr_last(rev(ktree_get(Flags, FlagsT)))]
+        ++ hwaddr_last(comp_ifaddrs_3(FlagsL, FlagsT));
+comp_ifaddrs_3([], _FlagsT) ->
+    [].
+
+%% Place hwaddr last to look more like legacy emulation
+hwaddr_last(Opts) ->
+    hwaddr_last(Opts, Opts, []).
+%%
+hwaddr_last([{hwaddr,_} = Opt|Opts], L, R) ->
+    hwaddr_last(Opts, L, [Opt|R]);
+hwaddr_last([_|Opts], L, R) ->
+    hwaddr_last(Opts, L, R);
+hwaddr_last([], L, []) ->
+    L;
+hwaddr_last([], L, R) ->
+    rev(hwaddr_last(L, []), rev(R)).
+%%
+hwaddr_last([{hwaddr,_}|Opts], R) ->
+    hwaddr_last(Opts, R);
+hwaddr_last([Opt|Opts], R) ->
+    hwaddr_last(Opts, [Opt|R]);
+hwaddr_last([], R) ->
+    R.
+
 
 %% Legacy emulation of getifaddrs
 
@@ -912,21 +957,19 @@ getifaddrs_ifget(_, []) -> [];
 getifaddrs_ifget(S, [IF|IFs]) ->
     case ifget(S, IF, [flags]) of
 	{ok,[{flags,Flags}]=FlagsVals} ->
-	    BroadOpts =
-		case member(broadcast, Flags) of
-		    true ->
-			[broadaddr,hwaddr];
-		    false ->
-			[hwaddr]
-		end,
-	    P2POpts =
-		case member(pointtopoint, Flags) of
-		    true ->
-			[dstaddr|BroadOpts];
-		    false ->
-			BroadOpts
-		end,
-	    getifaddrs_ifget(S, IFs, IF, FlagsVals, [addr,netmask|P2POpts]);
+            GetOpts =
+                case member(pointtopoint, Flags) of
+                    true ->
+                        [dstaddr,hwaddr];
+                    false ->
+                        case member(broadcast, Flags) of
+                            true ->
+                                [broadaddr,hwaddr];
+                            false ->
+                                [hwaddr]
+                        end
+                end,
+	    getifaddrs_ifget(S, IFs, IF, FlagsVals, [addr,netmask|GetOpts]);
 	_ ->
 	    getifaddrs_ifget(S, IFs, IF, [], [addr,netmask,hwaddr])
     end.
@@ -2500,7 +2543,7 @@ get_addrs([F|Addrs]) ->
     [Addr|get_addrs(Rest)].
 
 get_addr(?INET_AF_LOCAL, [N|Addr]) ->
-    {A,Rest} = lists:split(N, Addr),
+    {A,Rest} = split(N, Addr),
     {{local,iolist_to_binary(A)},Rest};
 get_addr(?INET_AF_UNSPEC, Rest) ->
     {{unspec,<<>>},Rest};