Introducing src_pid for mmap header for accurate buf completion.

This allows to use shared memory to communicate with main process.

This patch changes shared memory segment format and breaks compatibility
with older modules.

1 files changed, 25 insertions, 13 deletions

diff --git a/src/nxt_port_memory.c b/src/nxt_port_memory.c
index 677421e3..997ce383 100644
--- a/src/nxt_port_memory.c
+++ b/src/nxt_port_memory.c
@@ -107,6 +107,13 @@ nxt_port_mmap_buf_completion(nxt_task_t *task, void *obj, void *data)
 
     hdr = data;
 
+    if (nxt_slow_path(hdr->src_pid != nxt_pid && hdr->dst_pid != nxt_pid)) {
+        nxt_debug(task, "mmap buf completion: mmap for other process pair "
+                  "%PI->%PI", hdr->src_pid, hdr->dst_pid);
+
+        goto release_buf;
+    }
+
     if (b->is_port_mmap_sent && b->mem.pos > b->mem.start) {
         /*
          * Chunks until b->mem.pos has been sent to other side,
@@ -123,9 +130,9 @@ nxt_port_mmap_buf_completion(nxt_task_t *task, void *obj, void *data)
 
     nxt_port_mmap_free_junk(p, b->mem.end - p);
 
-    nxt_debug(task, "mmap buf completion: %p [%p,%d] (sent=%d), %PI,%d,%d", b,
-              b->mem.start, b->mem.end - b->mem.start, b->is_port_mmap_sent,
-              hdr->pid, hdr->id, c);
+    nxt_debug(task, "mmap buf completion: %p [%p,%d] (sent=%d), "
+              "%PI->%PI,%d,%d", b, b->mem.start, b->mem.end - b->mem.start,
+              b->is_port_mmap_sent, hdr->src_pid, hdr->dst_pid, hdr->id, c);
 
     while (p < b->mem.end) {
         nxt_port_mmap_set_chunk_free(hdr, c);
@@ -134,6 +141,8 @@ nxt_port_mmap_buf_completion(nxt_task_t *task, void *obj, void *data)
         c++;
     }
 
+release_buf:
+
     nxt_mp_release(mp, b);
 }
 
@@ -198,6 +207,9 @@ nxt_port_incoming_port_mmap(nxt_task_t *task, nxt_process_t *process,
         nxt_abort();
     }
 
+    nxt_assert(hdr->src_pid == process->pid);
+    nxt_assert(hdr->dst_pid == nxt_pid);
+
     hdr->sent_over = 0xFFFFu;
 
 fail:
@@ -298,7 +310,8 @@ nxt_port_new_port_mmap(nxt_task_t *task, nxt_process_t *process,
     nxt_memset(hdr->free_map, 0xFFU, sizeof(hdr->free_map));
 
     hdr->id = process->outgoing->nelts - 1;
-    hdr->pid = process->pid;
+    hdr->src_pid = nxt_pid;
+    hdr->dst_pid = process->pid;
     hdr->sent_over = port->id;
 
     /* Mark first chunk as busy */
@@ -307,8 +320,7 @@ nxt_port_new_port_mmap(nxt_task_t *task, nxt_process_t *process,
     /* Mark as busy chunk followed the last available chunk. */
     nxt_port_mmap_set_chunk_busy(hdr, PORT_MMAP_CHUNK_COUNT);
 
-    nxt_debug(task, "send mmap fd %FD to process %PI", fd,
-              port->pid);
+    nxt_debug(task, "send mmap fd %FD to process %PI", fd, port->pid);
 
     /* TODO handle error */
     (void) nxt_port_socket_write(task, port, NXT_PORT_MSG_MMAP, fd, 0, 0, NULL);
@@ -452,9 +464,9 @@ nxt_port_mmap_get_buf(nxt_task_t *task, nxt_port_t *port, size_t size)
         nchunks++;
     }
 
-    nxt_debug(task, "outgoing mmap buf allocation: %p [%p,%d] %PI,%d,%d", b,
-              b->mem.start, b->mem.end - b->mem.start,
-              hdr->pid, hdr->id, c);
+    nxt_debug(task, "outgoing mmap buf allocation: %p [%p,%d] %PI->%PI,%d,%d",
+              b, b->mem.start, b->mem.end - b->mem.start,
+              hdr->src_pid, hdr->dst_pid, hdr->id, c);
 
     c++;
     nchunks--;
@@ -576,9 +588,9 @@ nxt_port_mmap_get_incoming_buf(nxt_task_t *task, nxt_port_t *port,
 
     b->parent = hdr;
 
-    nxt_debug(task, "incoming mmap buf allocation: %p [%p,%d] %PI,%d,%d",
+    nxt_debug(task, "incoming mmap buf allocation: %p [%p,%d] %PI->%PI,%d,%d",
               b, b->mem.start, b->mem.end - b->mem.start,
-              hdr->pid, hdr->id, mmap_msg->chunk_id);
+              hdr->src_pid, hdr->dst_pid, hdr->id, mmap_msg->chunk_id);
 
     return b;
 }
@@ -699,10 +711,10 @@ nxt_port_mmap_get_method(nxt_task_t *task, nxt_port_t *port, nxt_buf_t *b)
                 break;
             }
 
-            if (port->pid != hdr->pid) {
+            if (port->pid != hdr->dst_pid) {
                 nxt_log_error(NXT_LOG_ERR, task->log,
                               "send mmap buffer for %PI to %PI, "
-                              "using plain mode", hdr->pid, port->pid);
+                              "using plain mode", hdr->dst_pid, port->pid);
 
                 m = NXT_PORT_METHOD_PLAIN;