foo.diff

diff --git a/server/config.c b/server/config.c
index 7c7a1e0033..754152b86b 100644
--- a/server/config.c
+++ b/server/config.c
@@ -45,37 +45,42 @@
 #include "http_protocol.h"
 #include "http_core.h"
 #include "http_log.h"      /* for errors in parse_htaccess */
 #include "http_request.h"  /* for default_handler (see invoke_handler) */
 #include "http_main.h"
 #include "http_vhost.h"
 #include "util_cfgtree.h"
 #include "util_varbuf.h"
 #include "mpm_common.h"
 
+#include "setjmp.h"
+#include "apr_signal.h"
+
 #define APLOG_UNSET   (APLOG_NO_MODULE - 1)
 /* we know core's module_index is 0 */
 #undef APLOG_MODULE_INDEX
 #define APLOG_MODULE_INDEX AP_CORE_MODULE_INDEX
 
 AP_DECLARE_DATA const char *ap_server_argv0 = NULL;
 AP_DECLARE_DATA const char *ap_server_root = NULL;
 AP_DECLARE_DATA const char *ap_runtime_dir = NULL;
 AP_DECLARE_DATA server_rec *ap_server_conf = NULL;
 AP_DECLARE_DATA apr_pool_t *ap_pglobal = NULL;
 
 AP_DECLARE_DATA apr_array_header_t *ap_server_pre_read_config = NULL;
 AP_DECLARE_DATA apr_array_header_t *ap_server_post_read_config = NULL;
 AP_DECLARE_DATA apr_array_header_t *ap_server_config_defines = NULL;
 
 AP_DECLARE_DATA ap_directive_t *ap_conftree = NULL;
 
+AP_DECLARE_DATA sigjmp_buf ap_invoke_handler_jmpenv;
+
 APR_HOOK_STRUCT(
            APR_HOOK_LINK(header_parser)
            APR_HOOK_LINK(pre_config)
            APR_HOOK_LINK(check_config)
            APR_HOOK_LINK(post_config)
            APR_HOOK_LINK(open_logs)
            APR_HOOK_LINK(child_init)
            APR_HOOK_LINK(handler)
            APR_HOOK_LINK(quick_handler)
            APR_HOOK_LINK(optional_fn_retrieve)
@@ -370,20 +375,25 @@ static int invoke_filter_init(request_rec *r, ap_filter_t *filters)
             int result = filters->frec->filter_init_func(filters);
             if (result != OK) {
                 return result;
             }
         }
         filters = filters->next;
     }
     return OK;
 }
 
+static void ap_invoke_handler_timeout(int sig)
+{
+    siglongjmp(ap_invoke_handler_jmpenv, 1);
+}
+
 AP_CORE_DECLARE(int) ap_invoke_handler(request_rec *r)
 {
     const char *handler;
     const char *p;
     int result;
     const char *old_handler = r->handler;
     const char *ignore;
 
     /*
      * The new insert_filter stage makes the most sense here.  We only use
@@ -424,22 +434,44 @@ AP_CORE_DECLARE(int) ap_invoke_handler(request_rec *r)
                 *p2='\0';
             }
         }
         else {
             handler = AP_DEFAULT_HANDLER_NAME;
         }
 
         r->handler = handler;
     }
 
-    result = ap_run_handler(r);
+    struct itimerval ntimer;
+    struct sigaction sigact;
+    int jmpv;
 
+    jmpv = sigsetjmp(ap_invoke_handler_jmpenv, 1);
+    if (jmpv == 0) {
+        // Timeout after 50ms
+        ntimer.it_interval.tv_sec = 0;
+        ntimer.it_interval.tv_usec = 0;
+        ntimer.it_value.tv_sec = 0;
+        ntimer.it_value.tv_usec = 50 * 1000;
+        setitimer(ITIMER_REAL, &ntimer, NULL);
+
+        // Install signal handler
+        apr_signal(SIGALRM, ap_invoke_handler_timeout);
+
+        // Run handler
+        result = ap_run_handler(r);
+        apr_signal(SIGALRM, SIG_IGN);
+    } else {
+        // Timed out; clear signal handler
+        apr_signal(SIGALRM, SIG_IGN);
+        result = HTTP_GATEWAY_TIME_OUT;
+    }
     r->handler = old_handler;
 
     if (result == DECLINED && r->handler && r->filename) {
         ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, APLOGNO(00523)
             "handler \"%s\" not found for: %s", r->handler, r->filename);
     }
     if ((result != OK) && (result != DONE) && (result != DECLINED) && (result != SUSPENDED)
         && (result != AP_FILTER_ERROR) /* ap_die() knows about this specifically */
         && !ap_is_HTTP_VALID_RESPONSE(result)) {
         /* If a module is deliberately returning something else

Shitty proof of concept. Works with mpm=prefork only. Might be able to generalize for mpm=event etc using timerfd* or signalfd*.