Fixed ngx_open_cached_file() error handling.

If of.err is 0, it means that there was a memory allocation error
and no further logging and/or processing is needed.  The of.failed
string can be only accessed if of.err is not 0.

src/http/modules/ngx_http_index_module.c

diff --git a/src/http/modules/ngx_http_index_module.c b/src/http/modules/ngx_http_index_module.c
index d3544db..c144b31 100644
--- a/src/http/modules/ngx_http_index_module.c
+++ b/src/http/modules/ngx_http_index_module.c
@@ -217,13 +217,13 @@
         if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool)
             != NGX_OK)
         {
-            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, of.err,
-                           "%s \"%s\" failed", of.failed, path.data);
-
             if (of.err == 0) {
                 return NGX_HTTP_INTERNAL_SERVER_ERROR;
             }
 
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, of.err,
+                           "%s \"%s\" failed", of.failed, path.data);
+
 #if (NGX_HAVE_OPENAT)
             if (of.err == NGX_EMLINK
                 || of.err == NGX_ELOOP)

src/http/modules/ngx_http_log_module.c

diff --git a/src/http/modules/ngx_http_log_module.c b/src/http/modules/ngx_http_log_module.c
index 330dc7e..917ed55 100644
--- a/src/http/modules/ngx_http_log_module.c
+++ b/src/http/modules/ngx_http_log_module.c
@@ -552,6 +552,11 @@
     if (ngx_open_cached_file(llcf->open_file_cache, &log, &of, r->pool)
         != NGX_OK)
     {
+        if (of.err == 0) {
+            /* simulate successful logging */
+            return len;
+        }
+
         ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
                       "%s \"%s\" failed", of.failed, log.data);
         /* simulate successful logging */

src/http/ngx_http_core_module.c

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index c3957ba..292671d 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -1314,6 +1314,11 @@
         if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool)
             != NGX_OK)
         {
+            if (of.err == 0) {
+                ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
+                return NGX_OK;
+            }
+
             if (of.err != NGX_ENOENT
                 && of.err != NGX_ENOTDIR
                 && of.err != NGX_ENAMETOOLONG)

src/http/ngx_http_script.c

diff --git a/src/http/ngx_http_script.c b/src/http/ngx_http_script.c
index cc4d679..96f3ec6 100644
--- a/src/http/ngx_http_script.c
+++ b/src/http/ngx_http_script.c
@@ -1513,6 +1513,12 @@
     if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool)
         != NGX_OK)
     {
+        if (of.err == 0) {
+            e->ip = ngx_http_script_exit;
+            e->status = NGX_HTTP_INTERNAL_SERVER_ERROR;
+            return;
+        }
+
         if (of.err != NGX_ENOENT
             && of.err != NGX_ENOTDIR
             && of.err != NGX_ENAMETOOLONG)

src/stream/ngx_stream_log_module.c

diff --git a/src/stream/ngx_stream_log_module.c b/src/stream/ngx_stream_log_module.c
index 6b29340..466bdda 100644
--- a/src/stream/ngx_stream_log_module.c
+++ b/src/stream/ngx_stream_log_module.c
@@ -443,6 +443,11 @@
                              s->connection->pool)
         != NGX_OK)
     {
+        if (of.err == 0) {
+            /* simulate successful logging */
+            return len;
+        }
+
         ngx_log_error(NGX_LOG_CRIT, s->connection->log, ngx_errno,
                       "%s \"%s\" failed", of.failed, log.data);
         /* simulate successful logging */