details: https://hg.nginx.org/njs/rev/c947a300b96c
branches:
changeset: 1568:c947a300b96c
user: Dmitry Volyntsev <xeioex@nginx.com>
date: Wed Nov 18 18:09:11 2020 +0000
description:
HTTP: fixed promise subrequest() with error_page redirect.

Previously, promise callbacks for a subrequest were stored in a
subrequest context. This is incorrect because a subrequest content may
be destroyed (for example when error_page with redirect is enabled for a
subrequest location).

The fix is to store callbacks in the parent context.

The issue was introduced in 6fccbc9f1288 (0.3.8).

diffstat:

nginx/ngx_http_js_module.c | 83 +++++++++++++++++++++++++++++++++++++++------
1 files changed, 72 insertions(+), 11 deletions(-)

diffs (134 lines):

diff -r e97f76121196 -r c947a300b96c nginx/ngx_http_js_module.c
--- a/nginx/ngx_http_js_module.c Tue Nov 17 13:22:34 2020 +0000
+++ b/nginx/ngx_http_js_module.c Wed Nov 18 18:09:11 2020 +0000
@@ -44,12 +44,18 @@ typedef struct {
njs_opaque_value_t request;
njs_opaque_value_t request_body;
ngx_str_t redirect_uri;
- njs_opaque_value_t promise_callbacks[2];
+ ngx_array_t promise_callbacks;
} ngx_http_js_ctx_t;


typedef struct {
ngx_http_request_t *request;
+ njs_opaque_value_t callbacks[2];
+} ngx_http_js_cb_t;
+
+
+typedef struct {
+ ngx_http_request_t *request;
njs_vm_event_t vm_event;
void *unused;
ngx_int_t ident;
@@ -2276,19 +2282,52 @@ static njs_int_t
ngx_http_js_promise_trampoline(njs_vm_t *vm, njs_value_t *args,
njs_uint_t nargs, njs_index_t unused)
{
+ ngx_uint_t i;
njs_function_t *callback;
+ ngx_http_js_cb_t *cb, *cbs;
ngx_http_js_ctx_t *ctx;
ngx_http_request_t *r;

r = njs_vm_external(vm, njs_argument(args, 1));
- ctx = ngx_http_get_module_ctx(r, ngx_http_js_module);
+ ctx = ngx_http_get_module_ctx(r->parent, ngx_http_js_module);

ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
- "js subrequest promise trampoline ctx: %p", ctx);
-
- callback = njs_value_function(njs_value_arg(&ctx->promise_callbacks[0]));
+ "js subrequest promise trampoline parent ctx: %p", ctx);
+
+ if (ctx == NULL) {
+ njs_vm_error(vm, "js subrequest: failed to get the parent context");
+ return NJS_ERROR;
+ }
+
+ cbs = ctx->promise_callbacks.elts;
+
+ if (cbs == NULL) {
+ goto fail;
+ }
+
+ cb = NULL;
+
+ for (i = 0; i < ctx->promise_callbacks.nelts; i++) {
+ if (cbs[i].request == r) {
+ cb = &cbs[i];
+ cb->request = NULL;
+ break;
+ }
+ }
+
+ if (cb == NULL) {
+ goto fail;
+ }
+
+ callback = njs_value_function(njs_value_arg(&cb->callbacks[0]));

return njs_vm_call(vm, callback, njs_argument(args, 1), 1);
+
+fail:
+
+ njs_vm_error(vm, "js subrequest: promise callback not found");
+
+ return NJS_ERROR;
}


@@ -2298,9 +2337,10 @@ ngx_http_js_ext_subrequest(njs_vm_t *vm,
{
ngx_int_t rc, promise;
njs_str_t uri_arg, args_arg, method_name, body_arg;
- ngx_uint_t method, methods_max, has_body, detached;
+ ngx_uint_t i, method, methods_max, has_body, detached;
njs_value_t *value, *arg, *options;
njs_function_t *callback;
+ ngx_http_js_cb_t *cb, *cbs;
ngx_http_js_ctx_t *ctx;
njs_opaque_value_t lvalue;
ngx_http_request_t *r, *sr;
@@ -2507,15 +2547,36 @@ ngx_http_js_ext_subrequest(njs_vm_t *vm,
}

if (promise) {
- ctx = ngx_pcalloc(sr->pool, sizeof(ngx_http_js_ctx_t));
- if (ctx == NULL) {
- return NGX_ERROR;
+ cbs = ctx->promise_callbacks.elts;
+
+ if (cbs == NULL) {
+ if (ngx_array_init(&ctx->promise_callbacks, r->pool, 4,
+ sizeof(ngx_http_js_cb_t)) != NGX_OK)
+ {
+ goto memory_error;
+ }
}

- ngx_http_set_ctx(sr, ctx, ngx_http_js_module);
+ cb = NULL;
+
+ for (i = 0; i < ctx->promise_callbacks.nelts; i++) {
+ if (cbs[i].request == NULL) {
+ cb = &cbs[i];
+ break;
+ }
+ }
+
+ if (i == ctx->promise_callbacks.nelts) {
+ cb = ngx_array_push(&ctx->promise_callbacks);
+ if (cb == NULL) {
+ goto memory_error;
+ }
+ }
+
+ cb->request = sr;

return njs_vm_promise_create(vm, njs_vm_retval(vm),
- njs_value_arg(&ctx->promise_callbacks));
+ njs_value_arg(&cb->callbacks));
}

njs_value_undefined_set(njs_vm_retval(vm));
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