From f7da39acea864b6402a1ccf91b2e214d3b3328a0 Mon Sep 17 00:00:00 2001
From: hippoz <10706925-hippoz@users.noreply.gitlab.com>
Date: Tue, 3 Jan 2023 17:20:02 +0200
Subject: [PATCH] better handle errors and noreply flag

---
 main.c   |  4 ++++
 server.c | 47 ++++++++++++++++++++++++++++++++++-------------
 wire.c   |  4 ++--
 3 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/main.c b/main.c
index 7083319..8bbe17a 100644
--- a/main.c
+++ b/main.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
+#include <signal.h>
 #include "match.h"
 #include "server.h"
 
@@ -23,6 +24,9 @@ int main(int argc, char *argv[])
     const char *socket_path = arg_shift(&argc, &argv);
     socket_path = socket_path == NULL ? "/tmp/jitterbug-unix0" : socket_path;
 
+    /* we handle send() errors directly in the code */
+    signal(SIGPIPE, SIG_IGN);
+
     struct jb_server *srv = jb_server_create(socket_path);
     if (srv == NULL) {
         fprintf(stderr, "server_create failed\n");
diff --git a/server.c b/server.c
index 0eb4d0b..5a7ed43 100644
--- a/server.c
+++ b/server.c
@@ -249,26 +249,47 @@ int jb_server_broadcast_message(struct jb_server *s, wire_message_t *msg, wire_c
     return 0;
 }
 
+int jb_server_unicast_message(struct jb_server *s, wire_message_t *msg, wire_context_t *ctx, char *target_name, char *sender_unique_name)
+{
+    struct jb_client *target = jb_server_name_find_client(s, target_name);
+    if (!target) {
+        return -1;
+    }
+
+    uint8_t reply_data[4096];
+    memset(reply_data, 0, 4096);
+    wire_context_t reply_ctx = {
+        .byte_cursor = 0,
+        .data = reply_data,
+        .data_len = 4096,
+    };
+
+    TRYST(wire_compose_unicast_reply(&reply_ctx, ctx, msg, sender_unique_name));
+    TRYST(send(target->fd, reply_data, reply_ctx.byte_cursor, 0));
+
+    return 0;
+}
+
 #define _reply_begin(M_sig) \
-    do { \
+    if (!(msg.flags & DBUS_FLAG_NO_REPLY_EXPECTED)) { \
         TRYST(wire_compose_reply(&reply_ctx, &msg, (M_sig), &body_length)); \
         body_start = reply_ctx.byte_cursor; \
-    } while(0); \
 
 #define _reply_end() \
-    do { \
         *body_length = reply_ctx.byte_cursor - body_start; \
         if (send(s->fds[i].fd, reply_data, reply_ctx.byte_cursor, 0) != reply_ctx.byte_cursor) { \
             return -1; \
         } \
         printf("send: sent %d bytes!\n", reply_ctx.byte_cursor); \
-    } while(0); \
+    } /* if (!(msg.flags & DBUS_FLAG_NO_REPLY_EXPECTED)) */
 
 #define _reply_error(message) \
     do { \
-        TRYST(wire_compose_error(&reply_ctx, &msg, (message))); \
-        if (send(s->fds[i].fd, reply_data, reply_ctx.byte_cursor, 0) != reply_ctx.byte_cursor) { \
-            return -1; \
+        if (!(msg.flags & DBUS_FLAG_NO_REPLY_EXPECTED)) { \
+            TRYST(wire_compose_error(&reply_ctx, &msg, (message))); \
+            if (send(s->fds[i].fd, reply_data, reply_ctx.byte_cursor, 0) != reply_ctx.byte_cursor) { \
+                return -1; \
+            } \
         } \
     } while(0) \
 
@@ -536,16 +557,16 @@ int jb_server_client_process_message(struct jb_server *s, int i, uint8_t *data,
         }
         if (destination_field->present) {
             /* unicast */
-            struct jb_client *target = jb_server_name_find_client(s, destination_field->t.str);
-            if (!target) {
-                _reply_error("org.freedesktop.DBus.Error.NameHasNoOwner");
+            if (jb_server_unicast_message(s, &msg, &ctx, destination_field->t.str, s->names[client->unique_name_index].name) < 0) {
+                _reply_error("xyz.hippoz.jitterbug.UnicastFailed");
                 return 0;
             }
-            TRYST(wire_compose_unicast_reply(&reply_ctx, &ctx, &msg, s->names[client->unique_name_index].name));
-            TRYST(send(target->fd, reply_data, reply_ctx.byte_cursor, 0));
         } else {
             /* broadcast */
-            TRYST(jb_server_broadcast_message(s, &msg, &ctx, s->names[client->unique_name_index].name));
+            if (jb_server_broadcast_message(s, &msg, &ctx, s->names[client->unique_name_index].name) < 0) {
+                _reply_error("xyz.hippoz.jitterbug.BroadcastFailed");
+                return 0;
+            }
         }
     }
 
diff --git a/wire.c b/wire.c
index 382db6a..c0df1d5 100644
--- a/wire.c
+++ b/wire.c
@@ -172,7 +172,7 @@ int wire_compose_reply(wire_context_t *c, wire_message_t *msg, const char *signa
     
     TRYPTR(wire_set_u8(c, msg->endianness)); /* endianness */
     TRYPTR(wire_set_u8(c, DBUS_MESSAGE_METHOD_RETURN)); /* type */
-    TRYPTR(wire_set_u8(c, 0)); /* flags */
+    TRYPTR(wire_set_u8(c, 0 | DBUS_FLAG_NO_REPLY_EXPECTED)); /* flags */
     TRYPTR(wire_set_u8(c, DBUS_PROTOCOL_VERSION)); /* protocol_version */
     uint32_t *body_length = TRYPTR(wire_set_u32(c, 0)); /* body length */
     TRYPTR(wire_set_u32(c, msg->serial+1)); /* serial */
@@ -273,7 +273,7 @@ int wire_compose_unicast_reply(wire_context_t *c, wire_context_t *msg_c, wire_me
 {
     TRYPTR(wire_set_u8(c, msg->endianness)); /* endianness */
     TRYPTR(wire_set_u8(c, msg->type)); /* type */
-    TRYPTR(wire_set_u8(c, 0)); /* flags */
+    TRYPTR(wire_set_u8(c, msg->flags)); /* flags */
     TRYPTR(wire_set_u8(c, DBUS_PROTOCOL_VERSION)); /* protocol_version */
     TRYPTR(wire_set_u32(c, msg->body_length)); /* body length */
     TRYPTR(wire_set_u32(c, msg->serial)); /* serial */