Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_sub_filter_module.c @ 6699:9cf2dce316e5
Fixed log levels of configuration parsing errors.
All the errors that prevent loading configuration must be printed on the "emerg"
log level. Previously, nginx might silently fail to load configuration in some
cases as the default log level is "error".
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Tue, 20 Sep 2016 15:07:16 +0300 |
parents | f379b32e4733 |
children | f18c285c2e59 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_http_complex_value_t match; ngx_http_complex_value_t value; } ngx_http_sub_pair_t; typedef struct { ngx_str_t match; ngx_http_complex_value_t *value; } ngx_http_sub_match_t; typedef struct { ngx_uint_t min_match_len; ngx_uint_t max_match_len; u_char index[257]; u_char shift[256]; } ngx_http_sub_tables_t; typedef struct { ngx_uint_t dynamic; /* unsigned dynamic:1; */ ngx_array_t *pairs; ngx_http_sub_tables_t *tables; ngx_hash_t types; ngx_flag_t once; ngx_flag_t last_modified; ngx_array_t *types_keys; ngx_array_t *matches; } ngx_http_sub_loc_conf_t; typedef struct { ngx_str_t saved; ngx_str_t looked; ngx_uint_t once; /* unsigned once:1 */ ngx_buf_t *buf; u_char *pos; u_char *copy_start; u_char *copy_end; ngx_chain_t *in; ngx_chain_t *out; ngx_chain_t **last_out; ngx_chain_t *busy; ngx_chain_t *free; ngx_str_t *sub; ngx_uint_t applied; ngx_int_t offset; ngx_uint_t index; ngx_http_sub_tables_t *tables; ngx_array_t *matches; } ngx_http_sub_ctx_t; static ngx_uint_t ngx_http_sub_cmp_index; static ngx_int_t ngx_http_sub_output(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx); static ngx_int_t ngx_http_sub_parse(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx, ngx_uint_t flush); static ngx_int_t ngx_http_sub_match(ngx_http_sub_ctx_t *ctx, ngx_int_t start, ngx_str_t *m); static char * ngx_http_sub_filter(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static void *ngx_http_sub_create_conf(ngx_conf_t *cf); static char *ngx_http_sub_merge_conf(ngx_conf_t *cf, void *parent, void *child); static void ngx_http_sub_init_tables(ngx_http_sub_tables_t *tables, ngx_http_sub_match_t *match, ngx_uint_t n); static ngx_int_t ngx_http_sub_cmp_matches(const void *one, const void *two); static ngx_int_t ngx_http_sub_filter_init(ngx_conf_t *cf); static ngx_command_t ngx_http_sub_filter_commands[] = { { ngx_string("sub_filter"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_http_sub_filter, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("sub_filter_types"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE, ngx_http_types_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_sub_loc_conf_t, types_keys), &ngx_http_html_default_types[0] }, { ngx_string("sub_filter_once"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_sub_loc_conf_t, once), NULL }, { ngx_string("sub_filter_last_modified"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_sub_loc_conf_t, last_modified), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_sub_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_sub_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_sub_create_conf, /* create location configuration */ ngx_http_sub_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_sub_filter_module = { NGX_MODULE_V1, &ngx_http_sub_filter_module_ctx, /* module context */ ngx_http_sub_filter_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_http_output_header_filter_pt ngx_http_next_header_filter; static ngx_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_sub_header_filter(ngx_http_request_t *r) { ngx_str_t *m; ngx_uint_t i, j, n; ngx_http_sub_ctx_t *ctx; ngx_http_sub_pair_t *pairs; ngx_http_sub_match_t *matches; ngx_http_sub_loc_conf_t *slcf; slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module); if (slcf->pairs == NULL || r->headers_out.content_length_n == 0 || ngx_http_test_content_type(r, &slcf->types) == NULL) { return ngx_http_next_header_filter(r); } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_sub_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } if (slcf->dynamic == 0) { ctx->tables = slcf->tables; ctx->matches = slcf->matches; } else { pairs = slcf->pairs->elts; n = slcf->pairs->nelts; matches = ngx_pcalloc(r->pool, sizeof(ngx_http_sub_match_t) * n); if (matches == NULL) { return NGX_ERROR; } j = 0; for (i = 0; i < n; i++) { matches[j].value = &pairs[i].value; if (pairs[i].match.lengths == NULL) { matches[j].match = pairs[i].match.value; j++; continue; } m = &matches[j].match; if (ngx_http_complex_value(r, &pairs[i].match, m) != NGX_OK) { return NGX_ERROR; } if (m->len == 0) { continue; } ngx_strlow(m->data, m->data, m->len); j++; } if (j == 0) { return ngx_http_next_header_filter(r); } ctx->matches = ngx_palloc(r->pool, sizeof(ngx_array_t)); if (ctx->matches == NULL) { return NGX_ERROR; } ctx->matches->elts = matches; ctx->matches->nelts = j; ctx->tables = ngx_palloc(r->pool, sizeof(ngx_http_sub_tables_t)); if (ctx->tables == NULL) { return NGX_ERROR; } ngx_http_sub_init_tables(ctx->tables, ctx->matches->elts, ctx->matches->nelts); } ngx_http_set_ctx(r, ctx, ngx_http_sub_filter_module); ctx->saved.data = ngx_pnalloc(r->pool, ctx->tables->max_match_len - 1); if (ctx->saved.data == NULL) { return NGX_ERROR; } ctx->looked.data = ngx_pnalloc(r->pool, ctx->tables->max_match_len - 1); if (ctx->looked.data == NULL) { return NGX_ERROR; } ctx->offset = ctx->tables->min_match_len - 1; ctx->last_out = &ctx->out; r->filter_need_in_memory = 1; if (r == r->main) { ngx_http_clear_content_length(r); if (!slcf->last_modified) { ngx_http_clear_last_modified(r); ngx_http_clear_etag(r); } else { ngx_http_weak_etag(r); } } return ngx_http_next_header_filter(r); } static ngx_int_t ngx_http_sub_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_buf_t *b; ngx_str_t *sub; ngx_uint_t flush, last; ngx_chain_t *cl; ngx_http_sub_ctx_t *ctx; ngx_http_sub_match_t *match; ngx_http_sub_loc_conf_t *slcf; ctx = ngx_http_get_module_ctx(r, ngx_http_sub_filter_module); if (ctx == NULL) { return ngx_http_next_body_filter(r, in); } if ((in == NULL && ctx->buf == NULL && ctx->in == NULL && ctx->busy == NULL)) { return ngx_http_next_body_filter(r, in); } if (ctx->once && (ctx->buf == NULL || ctx->in == NULL)) { if (ctx->busy) { if (ngx_http_sub_output(r, ctx) == NGX_ERROR) { return NGX_ERROR; } } return ngx_http_next_body_filter(r, in); } /* add the incoming chain to the chain ctx->in */ if (in) { if (ngx_chain_add_copy(r->pool, &ctx->in, in) != NGX_OK) { return NGX_ERROR; } } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http sub filter \"%V\"", &r->uri); flush = 0; last = 0; while (ctx->in || ctx->buf) { if (ctx->buf == NULL) { ctx->buf = ctx->in->buf; ctx->in = ctx->in->next; ctx->pos = ctx->buf->pos; } if (ctx->buf->flush || ctx->buf->recycled) { flush = 1; } if (ctx->in == NULL) { last = flush; } b = NULL; while (ctx->pos < ctx->buf->last) { rc = ngx_http_sub_parse(r, ctx, last); ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "parse: %i, looked: \"%V\" %p-%p", rc, &ctx->looked, ctx->copy_start, ctx->copy_end); if (rc == NGX_ERROR) { return rc; } if (ctx->saved.len) { ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "saved: \"%V\"", &ctx->saved); cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); b->pos = ngx_pnalloc(r->pool, ctx->saved.len); if (b->pos == NULL) { return NGX_ERROR; } ngx_memcpy(b->pos, ctx->saved.data, ctx->saved.len); b->last = b->pos + ctx->saved.len; b->memory = 1; *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->saved.len = 0; } if (ctx->copy_start != ctx->copy_end) { cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memcpy(b, ctx->buf, sizeof(ngx_buf_t)); b->pos = ctx->copy_start; b->last = ctx->copy_end; b->shadow = NULL; b->last_buf = 0; b->last_in_chain = 0; b->recycled = 0; if (b->in_file) { b->file_last = b->file_pos + (b->last - ctx->buf->pos); b->file_pos += b->pos - ctx->buf->pos; } *ctx->last_out = cl; ctx->last_out = &cl->next; } if (rc == NGX_AGAIN) { continue; } /* rc == NGX_OK */ cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module); if (ctx->sub == NULL) { ctx->sub = ngx_pcalloc(r->pool, sizeof(ngx_str_t) * ctx->matches->nelts); if (ctx->sub == NULL) { return NGX_ERROR; } } sub = &ctx->sub[ctx->index]; if (sub->data == NULL) { match = ctx->matches->elts; if (ngx_http_complex_value(r, match[ctx->index].value, sub) != NGX_OK) { return NGX_ERROR; } } if (sub->len) { b->memory = 1; b->pos = sub->data; b->last = sub->data + sub->len; } else { b->sync = 1; } *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->index = 0; ctx->once = slcf->once && (++ctx->applied == ctx->matches->nelts); continue; } if (ctx->looked.len && (ctx->buf->last_buf || ctx->buf->last_in_chain)) { cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); b->pos = ctx->looked.data; b->last = b->pos + ctx->looked.len; b->memory = 1; *ctx->last_out = cl; ctx->last_out = &cl->next; ctx->looked.len = 0; } if (ctx->buf->last_buf || ctx->buf->flush || ctx->buf->sync || ngx_buf_in_memory(ctx->buf)) { if (b == NULL) { cl = ngx_chain_get_free_buf(r->pool, &ctx->free); if (cl == NULL) { return NGX_ERROR; } b = cl->buf; ngx_memzero(b, sizeof(ngx_buf_t)); b->sync = 1; *ctx->last_out = cl; ctx->last_out = &cl->next; } b->last_buf = ctx->buf->last_buf; b->last_in_chain = ctx->buf->last_in_chain; b->flush = ctx->buf->flush; b->shadow = ctx->buf; b->recycled = ctx->buf->recycled; } ctx->buf = NULL; } if (ctx->out == NULL && ctx->busy == NULL) { return NGX_OK; } return ngx_http_sub_output(r, ctx); } static ngx_int_t ngx_http_sub_output(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx) { ngx_int_t rc; ngx_buf_t *b; ngx_chain_t *cl; #if 1 b = NULL; for (cl = ctx->out; cl; cl = cl->next) { ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "sub out: %p %p", cl->buf, cl->buf->pos); if (cl->buf == b) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "the same buf was used in sub"); ngx_debug_point(); return NGX_ERROR; } b = cl->buf; } #endif rc = ngx_http_next_body_filter(r, ctx->out); if (ctx->busy == NULL) { ctx->busy = ctx->out; } else { for (cl = ctx->busy; cl->next; cl = cl->next) { /* void */ } cl->next = ctx->out; } ctx->out = NULL; ctx->last_out = &ctx->out; while (ctx->busy) { cl = ctx->busy; b = cl->buf; if (ngx_buf_size(b) != 0) { break; } if (b->shadow) { b->shadow->pos = b->shadow->last; } ctx->busy = cl->next; if (ngx_buf_in_memory(b) || b->in_file) { /* add data bufs only to the free buf chain */ cl->next = ctx->free; ctx->free = cl; } } if (ctx->in || ctx->buf) { r->buffered |= NGX_HTTP_SUB_BUFFERED; } else { r->buffered &= ~NGX_HTTP_SUB_BUFFERED; } return rc; } static ngx_int_t ngx_http_sub_parse(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx, ngx_uint_t flush) { u_char *p, c; ngx_str_t *m; ngx_int_t offset, start, next, end, len, rc; ngx_uint_t shift, i, j; ngx_http_sub_match_t *match; ngx_http_sub_tables_t *tables; ngx_http_sub_loc_conf_t *slcf; slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module); tables = ctx->tables; match = ctx->matches->elts; offset = ctx->offset; end = ctx->buf->last - ctx->pos; if (ctx->once) { /* sets start and next to end */ offset = end + (ngx_int_t) tables->min_match_len - 1; goto again; } while (offset < end) { c = offset < 0 ? ctx->looked.data[ctx->looked.len + offset] : ctx->pos[offset]; c = ngx_tolower(c); shift = tables->shift[c]; if (shift > 0) { offset += shift; continue; } /* a potential match */ start = offset - (ngx_int_t) tables->min_match_len + 1; i = ngx_max(tables->index[c], ctx->index); j = tables->index[c + 1]; while (i != j) { if (slcf->once && ctx->sub && ctx->sub[i].data) { goto next; } m = &match[i].match; rc = ngx_http_sub_match(ctx, start, m); if (rc == NGX_DECLINED) { goto next; } ctx->index = i; if (rc == NGX_AGAIN) { goto again; } ctx->offset = offset + (ngx_int_t) m->len; next = start + (ngx_int_t) m->len; end = ngx_max(next, 0); rc = NGX_OK; goto done; next: i++; } offset++; ctx->index = 0; } if (flush) { for ( ;; ) { start = offset - (ngx_int_t) tables->min_match_len + 1; if (start >= end) { break; } for (i = 0; i < ctx->matches->nelts; i++) { m = &match[i].match; if (ngx_http_sub_match(ctx, start, m) == NGX_AGAIN) { goto again; } } offset++; } } again: ctx->offset = offset; start = offset - (ngx_int_t) tables->min_match_len + 1; next = start; rc = NGX_AGAIN; done: /* send [ - looked.len, start ] to client */ ctx->saved.len = ctx->looked.len + ngx_min(start, 0); ngx_memcpy(ctx->saved.data, ctx->looked.data, ctx->saved.len); ctx->copy_start = ctx->pos; ctx->copy_end = ctx->pos + ngx_max(start, 0); /* save [ next, end ] in looked */ len = ngx_min(next, 0); p = ctx->looked.data; p = ngx_movemem(p, p + ctx->looked.len + len, - len); len = ngx_max(next, 0); p = ngx_cpymem(p, ctx->pos + len, end - len); ctx->looked.len = p - ctx->looked.data; /* update position */ ctx->pos += end; ctx->offset -= end; return rc; } static ngx_int_t ngx_http_sub_match(ngx_http_sub_ctx_t *ctx, ngx_int_t start, ngx_str_t *m) { u_char *p, *last, *pat, *pat_end; pat = m->data; pat_end = m->data + m->len; if (start >= 0) { p = ctx->pos + start; } else { last = ctx->looked.data + ctx->looked.len; p = last + start; while (p < last && pat < pat_end) { if (ngx_tolower(*p) != *pat) { return NGX_DECLINED; } p++; pat++; } p = ctx->pos; } while (p < ctx->buf->last && pat < pat_end) { if (ngx_tolower(*p) != *pat) { return NGX_DECLINED; } p++; pat++; } if (pat != pat_end) { /* partial match */ return NGX_AGAIN; } return NGX_OK; } static char * ngx_http_sub_filter(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_sub_loc_conf_t *slcf = conf; ngx_str_t *value; ngx_http_sub_pair_t *pair; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; if (value[1].len == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "empty search pattern"); return NGX_CONF_ERROR; } if (slcf->pairs == NULL) { slcf->pairs = ngx_array_create(cf->pool, 1, sizeof(ngx_http_sub_pair_t)); if (slcf->pairs == NULL) { return NGX_CONF_ERROR; } } if (slcf->pairs->nelts == 255) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "number of search patterns exceeds 255"); return NGX_CONF_ERROR; } ngx_strlow(value[1].data, value[1].data, value[1].len); pair = ngx_array_push(slcf->pairs); if (pair == NULL) { return NGX_CONF_ERROR; } ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &pair->match; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } if (ccv.complex_value->lengths != NULL) { slcf->dynamic = 1; } else { ngx_strlow(pair->match.value.data, pair->match.value.data, pair->match.value.len); } ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[2]; ccv.complex_value = &pair->value; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; } static void * ngx_http_sub_create_conf(ngx_conf_t *cf) { ngx_http_sub_loc_conf_t *slcf; slcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_sub_loc_conf_t)); if (slcf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->dynamic = 0; * conf->pairs = NULL; * conf->tables = NULL; * conf->types = { NULL }; * conf->types_keys = NULL; * conf->matches = NULL; */ slcf->once = NGX_CONF_UNSET; slcf->last_modified = NGX_CONF_UNSET; return slcf; } static char * ngx_http_sub_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_uint_t i, n; ngx_http_sub_pair_t *pairs; ngx_http_sub_match_t *matches; ngx_http_sub_loc_conf_t *prev = parent; ngx_http_sub_loc_conf_t *conf = child; ngx_conf_merge_value(conf->once, prev->once, 1); ngx_conf_merge_value(conf->last_modified, prev->last_modified, 0); if (ngx_http_merge_types(cf, &conf->types_keys, &conf->types, &prev->types_keys, &prev->types, ngx_http_html_default_types) != NGX_OK) { return NGX_CONF_ERROR; } if (conf->pairs == NULL) { conf->dynamic = prev->dynamic; conf->pairs = prev->pairs; conf->matches = prev->matches; conf->tables = prev->tables; } if (conf->pairs && conf->dynamic == 0 && conf->tables == NULL) { pairs = conf->pairs->elts; n = conf->pairs->nelts; matches = ngx_palloc(cf->pool, sizeof(ngx_http_sub_match_t) * n); if (matches == NULL) { return NGX_CONF_ERROR; } for (i = 0; i < n; i++) { matches[i].match = pairs[i].match.value; matches[i].value = &pairs[i].value; } conf->matches = ngx_palloc(cf->pool, sizeof(ngx_array_t)); if (conf->matches == NULL) { return NGX_CONF_ERROR; } conf->matches->elts = matches; conf->matches->nelts = n; conf->tables = ngx_palloc(cf->pool, sizeof(ngx_http_sub_tables_t)); if (conf->tables == NULL) { return NGX_CONF_ERROR; } ngx_http_sub_init_tables(conf->tables, conf->matches->elts, conf->matches->nelts); } return NGX_CONF_OK; } static void ngx_http_sub_init_tables(ngx_http_sub_tables_t *tables, ngx_http_sub_match_t *match, ngx_uint_t n) { u_char c; ngx_uint_t i, j, min, max, ch; min = match[0].match.len; max = match[0].match.len; for (i = 1; i < n; i++) { min = ngx_min(min, match[i].match.len); max = ngx_max(max, match[i].match.len); } tables->min_match_len = min; tables->max_match_len = max; ngx_http_sub_cmp_index = tables->min_match_len - 1; ngx_sort(match, n, sizeof(ngx_http_sub_match_t), ngx_http_sub_cmp_matches); min = ngx_min(min, 255); ngx_memset(tables->shift, min, 256); ch = 0; for (i = 0; i < n; i++) { for (j = 0; j < min; j++) { c = match[i].match.data[tables->min_match_len - 1 - j]; tables->shift[c] = ngx_min(tables->shift[c], (u_char) j); } c = match[i].match.data[tables->min_match_len - 1]; while (ch <= c) { tables->index[ch++] = (u_char) i; } } while (ch < 257) { tables->index[ch++] = (u_char) n; } } static ngx_int_t ngx_http_sub_cmp_matches(const void *one, const void *two) { ngx_int_t c1, c2; ngx_http_sub_match_t *first, *second; first = (ngx_http_sub_match_t *) one; second = (ngx_http_sub_match_t *) two; c1 = first->match.data[ngx_http_sub_cmp_index]; c2 = second->match.data[ngx_http_sub_cmp_index]; return c1 - c2; } static ngx_int_t ngx_http_sub_filter_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_sub_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_sub_body_filter; return NGX_OK; }