[nginx] Request body: introduced rb->last_saved flag.

[Maxim Dounin]

details:   https://hg.nginx.org/nginx/rev/185c86b830ef
branches:  
changeset: 7913:185c86b830ef
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Sun Aug 29 22:21:03 2021 +0300
description:
Request body: introduced rb->last_saved flag.

It indicates that the last buffer was received by the save filter,
and can be used to check this at higher levels.  To be used in the
following changes.

diffstat:

 src/http/ngx_http_request.h      |   1 +
 src/http/ngx_http_request_body.c |  72 ++++++++++++++++++++++++++++++---------
 2 files changed, 56 insertions(+), 17 deletions(-)

diffs (152 lines):

diff -r 96e09beaa2cf -r 185c86b830ef src/http/ngx_http_request.h
--- a/src/http/ngx_http_request.h	Sun Aug 29 22:20:54 2021 +0300
+++ b/src/http/ngx_http_request.h	Sun Aug 29 22:21:03 2021 +0300
@@ -302,6 +302,7 @@ typedef struct {
     ngx_chain_t                      *busy;
     ngx_http_chunked_t               *chunked;
     ngx_http_client_body_handler_pt   post_handler;
+    unsigned                          last_saved:1;
 } ngx_http_request_body_t;
 
 
diff -r 96e09beaa2cf -r 185c86b830ef src/http/ngx_http_request_body.c
--- a/src/http/ngx_http_request_body.c	Sun Aug 29 22:20:54 2021 +0300
+++ b/src/http/ngx_http_request_body.c	Sun Aug 29 22:21:03 2021 +0300
@@ -69,6 +69,7 @@ ngx_http_read_client_request_body(ngx_ht
      *     rb->busy = NULL;
      *     rb->chunked = NULL;
      *     rb->received = 0;
+     *     rb->last_saved = 0;
      */
 
     rb->rest = -1;
@@ -941,15 +942,32 @@ ngx_http_request_body_length_filter(ngx_
 
     rb = r->request_body;
 
+    out = NULL;
+    ll = &out;
+
     if (rb->rest == -1) {
         ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                        "http request body content length filter");
 
         rb->rest = r->headers_in.content_length_n;
-    }
+
+        if (rb->rest == 0) {
+
+            tl = ngx_chain_get_free_buf(r->pool, &rb->free);
+            if (tl == NULL) {
+                return NGX_HTTP_INTERNAL_SERVER_ERROR;
+            }
 
-    out = NULL;
-    ll = &out;
+            b = tl->buf;
+
+            ngx_memzero(b, sizeof(ngx_buf_t));
+
+            b->last_buf = 1;
+
+            *ll = tl;
+            ll = &tl->next;
+        }
+    }
 
     for (cl = in; cl; cl = cl->next) {
 
@@ -1013,6 +1031,9 @@ ngx_http_request_body_chunked_filter(ngx
 
     rb = r->request_body;
 
+    out = NULL;
+    ll = &out;
+
     if (rb->rest == -1) {
 
         ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
@@ -1029,9 +1050,6 @@ ngx_http_request_body_chunked_filter(ngx
         rb->rest = cscf->large_client_header_buffers.size;
     }
 
-    out = NULL;
-    ll = &out;
-
     for (cl = in; cl; cl = cl->next) {
 
         b = NULL;
@@ -1188,15 +1206,16 @@ ngx_int_t
 ngx_http_request_body_save_filter(ngx_http_request_t *r, ngx_chain_t *in)
 {
     ngx_buf_t                 *b;
-    ngx_chain_t               *cl;
+    ngx_chain_t               *cl, *tl, **ll;
     ngx_http_request_body_t   *rb;
 
     rb = r->request_body;
 
-#if (NGX_DEBUG)
+    ll = &rb->bufs;
+
+    for (cl = rb->bufs; cl; cl = cl->next) {
 
 #if 0
-    for (cl = rb->bufs; cl; cl = cl->next) {
         ngx_log_debug7(NGX_LOG_DEBUG_EVENT, r->connection->log, 0,
                        "http body old buf t:%d f:%d %p, pos %p, size: %z "
                        "file: %O, size: %O",
@@ -1205,10 +1224,13 @@ ngx_http_request_body_save_filter(ngx_ht
                        cl->buf->last - cl->buf->pos,
                        cl->buf->file_pos,
                        cl->buf->file_last - cl->buf->file_pos);
-    }
 #endif
 
+        ll = &cl->next;
+    }
+
     for (cl = in; cl; cl = cl->next) {
+
         ngx_log_debug7(NGX_LOG_DEBUG_EVENT, r->connection->log, 0,
                        "http body new buf t:%d f:%d %p, pos %p, size: %z "
                        "file: %O, size: %O",
@@ -1217,15 +1239,31 @@ ngx_http_request_body_save_filter(ngx_ht
                        cl->buf->last - cl->buf->pos,
                        cl->buf->file_pos,
                        cl->buf->file_last - cl->buf->file_pos);
+
+        if (cl->buf->last_buf) {
+
+            if (rb->last_saved) {
+                ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                              "duplicate last buf in save filter");
+                *ll = NULL;
+                return NGX_HTTP_INTERNAL_SERVER_ERROR;
+            }
+
+            rb->last_saved = 1;
+        }
+
+        tl = ngx_alloc_chain_link(r->pool);
+        if (tl == NULL) {
+            *ll = NULL;
+            return NGX_HTTP_INTERNAL_SERVER_ERROR;
+        }
+
+        tl->buf = cl->buf;
+        *ll = tl;
+        ll = &tl->next;
     }
 
-#endif
-
-    /* TODO: coalesce neighbouring buffers */
-
-    if (ngx_chain_add_copy(r->pool, &rb->bufs, in) != NGX_OK) {
-        return NGX_HTTP_INTERNAL_SERVER_ERROR;
-    }
+    *ll = NULL;
 
     if (r->request_body_no_buffering) {
         return NGX_OK;