Merge r1599012, r1601559, r1818624, r1819969, r1819970 from trunk:

mod_proxy_html: skip documents < 4 bytes
PR 56286
Micha Lenk


follow up r1599012:
C99 fix


Fix some style


mod_proxy_html: follow up to r1599012.

To determine whether or not HTML data are lower than 4 bytes, use a retain
buffer rather than assuming that all should be contained in a single bucket
with the next one being EOS (if any).


mod_proxy_html: don't depend on NUL terminated bucket data.

ap_regexec() wants NUL terminated strings, so use ap_regexec_len() instead.


Submitted by: niq, takashi, jailletc36, ylavic, ylavic
Reviewed by: jim, ylavic, icing


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1821073 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 60 insertions, 12 deletions

diff --git a/modules/filters/mod_proxy_html.c b/modules/filters/mod_proxy_html.c
index 1ea005bf28..78ebdab34e 100644
--- a/modules/filters/mod_proxy_html.c
+++ b/modules/filters/mod_proxy_html.c
@@ -108,6 +108,9 @@ typedef struct {
     size_t avail;
     const char *encoding;
     urlmap *map;
+    char rbuf[4];
+    apr_size_t rlen;
+    apr_size_t rmin;
 } saxctxt;
 
 
@@ -638,7 +641,7 @@ static void pstartElement(void *ctxt, const xmlChar *uname,
     }
 }
 
-static meta *metafix(request_rec *r, const char *buf)
+static meta *metafix(request_rec *r, const char *buf, apr_size_t len)
 {
     meta *ret = NULL;
     size_t offs = 0;
@@ -649,7 +652,8 @@ static meta *metafix(request_rec *r, const char *buf)
     ap_regmatch_t pmatch[2];
     char delim;
 
-    while (!ap_regexec(seek_meta, buf+offs, 2, pmatch, 0)) {
+    while (offs < len &&
+           !ap_regexec_len(seek_meta, buf + offs, len - offs, 2, pmatch, 0)) {
         header = NULL;
         content = NULL;
         p = buf+offs+pmatch[1].rm_eo;
@@ -844,6 +848,17 @@ static saxctxt *check_filter_init (ap_filter_t *f)
     return f->ctx;
 }
 
+static void prepend_rbuf(saxctxt *ctxt, apr_bucket_brigade *bb)
+{
+    if (ctxt->rlen) {
+        apr_bucket *b = apr_bucket_transient_create(ctxt->rbuf,
+                                                    ctxt->rlen,
+                                                    bb->bucket_alloc);
+        APR_BRIGADE_INSERT_HEAD(bb, b);
+        ctxt->rlen = 0;
+    }
+}
+
 static apr_status_t proxy_html_filter(ap_filter_t *f, apr_bucket_brigade *bb)
 {
     apr_bucket* b;
@@ -865,11 +880,15 @@ static apr_status_t proxy_html_filter(ap_filter_t *f, apr_bucket_brigade *bb)
         if (APR_BUCKET_IS_METADATA(b)) {
             if (APR_BUCKET_IS_EOS(b)) {
                 if (ctxt->parser != NULL) {
-                    consume_buffer(ctxt, buf, 0, 1);
+                    consume_buffer(ctxt, "", 0, 1);
+                }
+                else {
+                    prepend_rbuf(ctxt, ctxt->bb);
                 }
                 APR_BRIGADE_INSERT_TAIL(ctxt->bb,
-                apr_bucket_eos_create(ctxt->bb->bucket_alloc));
+                    apr_bucket_eos_create(ctxt->bb->bucket_alloc));
                 ap_pass_brigade(ctxt->f->next, ctxt->bb);
+                apr_brigade_cleanup(ctxt->bb);
             }
             else if (APR_BUCKET_IS_FLUSH(b)) {
                 /* pass on flush, except at start where it would cause
@@ -884,11 +903,30 @@ static apr_status_t proxy_html_filter(ap_filter_t *f, apr_bucket_brigade *bb)
                  == APR_SUCCESS) {
             if (ctxt->parser == NULL) {
                 const char *cenc;
+
+                /* For documents smaller than four bytes, there is no reason to do
+                 * HTML rewriting. The URL schema (i.e. 'http') needs four bytes alone.
+                 * And the HTML parser needs at least four bytes to initialise correctly.
+                 */
+                ctxt->rmin += bytes;
+                if (ctxt->rmin < sizeof(ctxt->rbuf)) {
+                    memcpy(ctxt->rbuf + ctxt->rlen, buf, bytes);
+                    ctxt->rlen += bytes;
+                    continue;
+                }
+                if (ctxt->rlen && ctxt->rlen < sizeof(ctxt->rbuf)) {
+                    apr_size_t rem = sizeof(ctxt->rbuf) - ctxt->rlen;
+                    memcpy(ctxt->rbuf + ctxt->rlen, buf, rem);
+                    ctxt->rlen += rem;
+                    buf += rem;
+                    bytes -= rem;
+                }
+
                 if (!xml2enc_charset ||
                     (xml2enc_charset(f->r, &enc, &cenc) != APR_SUCCESS)) {
                     if (!xml2enc_charset)
                         ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, f->r, APLOGNO(01422)
-                     "No i18n support found.  Install mod_xml2enc if required");
+                                      "No i18n support found.  Install mod_xml2enc if required");
                     enc = XML_CHAR_ENCODING_NONE;
                     ap_set_content_type(f->r, "text/html;charset=utf-8");
                 }
@@ -910,15 +948,25 @@ static apr_status_t proxy_html_filter(ap_filter_t *f, apr_bucket_brigade *bb)
                 }
 
                 ap_fputs(f->next, ctxt->bb, ctxt->cfg->doctype);
-                ctxt->parser = htmlCreatePushParserCtxt(&sax, ctxt, buf,
-                                                        4, 0, enc);
-                buf += 4;
-                bytes -= 4;
+
+                if (ctxt->rlen) {
+                    ctxt->parser = htmlCreatePushParserCtxt(&sax, ctxt,
+                                                            ctxt->rbuf,
+                                                            ctxt->rlen,
+                                                            NULL, enc);
+                }
+                else {
+                    ctxt->parser = htmlCreatePushParserCtxt(&sax, ctxt, buf, 4,
+                                                            NULL, enc);
+                    buf += 4;
+                    bytes -= 4;
+                }
                 if (ctxt->parser == NULL) {
-                    apr_status_t rv = ap_pass_brigade(f->next, bb);
+                    prepend_rbuf(ctxt, bb);
                     ap_remove_output_filter(f);
-                    return rv;
+                    return ap_pass_brigade(f->next, bb);
                 }
+                ctxt->rlen = 0;
                 apr_pool_cleanup_register(f->r->pool, ctxt->parser,
                                           (int(*)(void*))htmlFreeParserCtxt,
                                           apr_pool_cleanup_null);
@@ -928,7 +976,7 @@ static apr_status_t proxy_html_filter(ap_filter_t *f, apr_bucket_brigade *bb)
                                   "Unsupported parser opts %x", xmlopts);
 #endif
                 if (ctxt->cfg->metafix)
-                    m = metafix(f->r, buf);
+                    m = metafix(f->r, buf, bytes);
                 if (m) {
                     consume_buffer(ctxt, buf, m->start, 0);
                     consume_buffer(ctxt, buf+m->end, bytes-m->end, 0);