[PATCH 07 of 20] All non-unique input headers are now linked lists

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1650492324 -10800
#      Thu Apr 21 01:05:24 2022 +0300
# Node ID 238d1f5f438735432822689605fa37b1b0e01517
# Parent  50fe52f516ff9c148aa9e7dfcc1c31cc6a4929ae
All non-unique input headers are now linked lists.

The ngx_http_process_multi_header_lines() function is removed, as it is
exactly equivalent to ngx_http_process_header_line().  Similarly,
ngx_http_variable_header() is used instead of ngx_http_variable_headers().

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -22,8 +22,6 @@ static ngx_int_t ngx_http_process_header
     ngx_table_elt_t *h, ngx_uint_t offset);
 static ngx_int_t ngx_http_process_unique_header_line(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset);
-static ngx_int_t ngx_http_process_multi_header_lines(ngx_http_request_t *r,
-    ngx_table_elt_t *h, ngx_uint_t offset);
 static ngx_int_t ngx_http_process_host(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset);
 static ngx_int_t ngx_http_process_connection(ngx_http_request_t *r,
@@ -164,7 +162,7 @@ ngx_http_header_t  ngx_http_headers_in[]
 #if (NGX_HTTP_X_FORWARDED_FOR)
     { ngx_string("X-Forwarded-For"),
                  offsetof(ngx_http_headers_in_t, x_forwarded_for),
-                 ngx_http_process_multi_header_lines },
+                 ngx_http_process_header_line },
 #endif
 
 #if (NGX_HTTP_REALIP)
@@ -197,7 +195,7 @@ ngx_http_header_t  ngx_http_headers_in[]
 #endif
 
     { ngx_string("Cookie"), offsetof(ngx_http_headers_in_t, cookie),
-                 ngx_http_process_multi_header_lines },
+                 ngx_http_process_header_line },
 
     { ngx_null_string, 0, NULL }
 };
@@ -1742,10 +1740,10 @@ ngx_http_process_header_line(ngx_http_re
 
     ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
 
-    if (*ph == NULL) {
-        *ph = h;
-        h->next = NULL;
-    }
+    while (*ph) { ph = &(*ph)->next; }
+
+    *ph = h;
+    h->next = NULL;
 
     return NGX_OK;
 }
@@ -1851,13 +1849,10 @@ ngx_http_process_user_agent(ngx_http_req
 {
     u_char  *user_agent, *msie;
 
-    if (r->headers_in.user_agent) {
-        return NGX_OK;
+    if (ngx_http_process_header_line(r, h, offset) != NGX_OK) {
+        return NGX_ERROR;
     }
 
-    r->headers_in.user_agent = h;
-    h->next = NULL;
-
     /* check some widespread browsers while the header is in CPU cache */
 
     user_agent = h->value.data;
@@ -1919,23 +1914,6 @@ ngx_http_process_user_agent(ngx_http_req
 }
 
 
-static ngx_int_t
-ngx_http_process_multi_header_lines(ngx_http_request_t *r, ngx_table_elt_t *h,
-    ngx_uint_t offset)
-{
-    ngx_table_elt_t  **ph;
-
-    ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
-
-    while (*ph) { ph = &(*ph)->next; }
-
-    *ph = h;
-    h->next = NULL;
-
-    return NGX_OK;
-}
-
-
 ngx_int_t
 ngx_http_process_request_header(ngx_http_request_t *r)
 {
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -27,8 +27,6 @@ static ngx_int_t ngx_http_variable_heade
 
 static ngx_int_t ngx_http_variable_cookies(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
-static ngx_int_t ngx_http_variable_headers(ngx_http_request_t *r,
-    ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_headers_internal(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data, u_char sep);
 
@@ -178,7 +176,7 @@ static ngx_http_variable_t  ngx_http_cor
 #endif
 
 #if (NGX_HTTP_X_FORWARDED_FOR)
-    { ngx_string("http_x_forwarded_for"), NULL, ngx_http_variable_headers,
+    { ngx_string("http_x_forwarded_for"), NULL, ngx_http_variable_header,
       offsetof(ngx_http_request_t, headers_in.x_forwarded_for), 0, 0 },
 #endif
 
@@ -327,10 +325,10 @@ static ngx_http_variable_t  ngx_http_cor
     { ngx_string("sent_http_transfer_encoding"), NULL,
       ngx_http_variable_sent_transfer_encoding, 0, 0, 0 },
 
-    { ngx_string("sent_http_cache_control"), NULL, ngx_http_variable_headers,
+    { ngx_string("sent_http_cache_control"), NULL, ngx_http_variable_header,
       offsetof(ngx_http_request_t, headers_out.cache_control), 0, 0 },
 
-    { ngx_string("sent_http_link"), NULL, ngx_http_variable_headers,
+    { ngx_string("sent_http_link"), NULL, ngx_http_variable_header,
       offsetof(ngx_http_request_t, headers_out.link), 0, 0 },
 
     { ngx_string("limit_rate"), ngx_http_variable_set_limit_rate,
@@ -807,22 +805,7 @@ static ngx_int_t
 ngx_http_variable_header(ngx_http_request_t *r, ngx_http_variable_value_t *v,
     uintptr_t data)
 {
-    ngx_table_elt_t  *h;
-
-    h = *(ngx_table_elt_t **) ((char *) r + data);
-
-    if (h) {
-        v->len = h->value.len;
-        v->valid = 1;
-        v->no_cacheable = 0;
-        v->not_found = 0;
-        v->data = h->value.data;
-
-    } else {
-        v->not_found = 1;
-    }
-
-    return NGX_OK;
+    return ngx_http_variable_headers_internal(r, v, data, ',');
 }
 
 
@@ -835,14 +818,6 @@ ngx_http_variable_cookies(ngx_http_reque
 
 
 static ngx_int_t
-ngx_http_variable_headers(ngx_http_request_t *r,
-    ngx_http_variable_value_t *v, uintptr_t data)
-{
-    return ngx_http_variable_headers_internal(r, v, data, ',');
-}
-
-
-static ngx_int_t
 ngx_http_variable_headers_internal(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data, u_char sep)
 {