From b553ed2c9ca63a2ef834026cfe5469aa874dca89 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Thu, 17 Sep 2015 03:43:08 +0200
Subject: implemented children policies

---
 src/dropnroll.c   | 24 ++++++++++++------------
 src/sig_handler.c |  2 --
 src/sysexec.c     | 17 +++++++++++++++--
 src/sysexec.h     |  1 +
 4 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/src/dropnroll.c b/src/dropnroll.c
index 210a416..b70bbc5 100644
--- a/src/dropnroll.c
+++ b/src/dropnroll.c
@@ -113,18 +113,18 @@ int process_watch(int inotify_fd, read_buffer_t* buffer, watch_list_t* watch_lst
 
             char* const argv[] = { opt->script_, path, event->len > 0 ? event->name : "", buf, NULL };
             char* const evp[] = { NULL };
-            rh_exec(opt->script_, argv, evp, child_lst, opt);
-
-            snprintf(buf, 100, "new file in '%s', name='%s'", path, event->len > 0 ? event->name : "");
-            log_printf(NOTICE, "%s, executing script %s", buf, opt->script_);
-            client_t* client;
-            int listener_cnt = 0;
-            for(client = client_lst; client; client = client->next)
-              if(client->status_listener) {
-                send_response(client->fd, buf);
-                listener_cnt++;
-              }
-            log_printf(DEBUG, "sent status to %d additional listeners", listener_cnt);
+            if(!rh_exec(opt->script_, argv, evp, child_lst, opt)) {
+              snprintf(buf, 100, "new file in '%s', name='%s'", path, event->len > 0 ? event->name : "");
+              log_printf(NOTICE, "%s, executing script %s", buf, opt->script_);
+              client_t* client;
+              int listener_cnt = 0;
+              for(client = client_lst; client; client = client->next)
+                if(client->status_listener) {
+                  send_response(client->fd, buf);
+                  listener_cnt++;
+                }
+              log_printf(DEBUG, "sent status to %d additional listeners", listener_cnt);
+            }
           }
 
           if(buffer->offset > len) {
diff --git a/src/sig_handler.c b/src/sig_handler.c
index 9e9e3e7..7287320 100644
--- a/src/sig_handler.c
+++ b/src/sig_handler.c
@@ -83,7 +83,6 @@ int signal_init()
      (sigaction(SIGHUP, &act, NULL) < 0) ||
      (sigaction(SIGUSR1, &act, NULL) < 0) ||
      (sigaction(SIGUSR2, &act, NULL) < 0) ||
-     (sigaction(SIGCHLD, &ign, NULL) < 0) ||
      (sigaction(SIGPIPE, &ign, NULL) < 0)) {
 
     log_printf(ERROR, "signal handling init failed (sigaction error: %s)", strerror(errno));
@@ -145,7 +144,6 @@ void signal_stop()
   sigaction(SIGHUP, &act, NULL);
   sigaction(SIGUSR1, &act, NULL);
   sigaction(SIGUSR2, &act, NULL);
-  sigaction(SIGCHLD, &act, NULL);
   sigaction(SIGPIPE, &act, NULL);
 
   close(sig_pipe_fds[0]);
diff --git a/src/sysexec.c b/src/sysexec.c
index abfd6f8..ae9a40c 100644
--- a/src/sysexec.c
+++ b/src/sysexec.c
@@ -23,6 +23,7 @@
 
 #include <unistd.h>
 #include <sys/types.h>
+#include <sys/signal.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <errno.h>
@@ -252,6 +253,14 @@ int child_list_num_running(child_list_t* list)
   return num;
 }
 
+void child_list_kill_oldest(child_list_t* list)
+{
+  if(!list || !list->first_)
+    return;
+
+  kill(list->first_->pid_, SIGKILL);
+}
+
 int rh_exec(const char* script, char* const argv[], char* const evp[], child_list_t* child_lst, options_t* opt)
 {
   if(!script)
@@ -262,8 +271,12 @@ int rh_exec(const char* script, char* const argv[], char* const evp[], child_lis
     return -2;
 
   if(child_list_num_running(child_lst) >= opt->max_children_) {
-    log_printf(INFO, "deferring script execution '%s'", script);
-    return 0;
+    switch(opt->children_policy_) {
+      case DEFER: log_printf(INFO, "children limit reached: deferring script execution '%s'", script); break;
+      case DROP: log_printf(INFO, "children limit reached: not calling '%s'", script); child_list_rm(child_lst, child); break;
+      case KILL_OLDEST: log_printf(INFO, "children limit reached: killing oldest child"); child_list_kill_oldest(child_lst); break;
+    }
+    return -3;
   }
 
   int ret = rh_exec_child(child);
diff --git a/src/sysexec.h b/src/sysexec.h
index 67dbda2..560a70f 100644
--- a/src/sysexec.h
+++ b/src/sysexec.h
@@ -49,6 +49,7 @@ void child_list_rm(child_list_t* list, child_list_element_t* child);
 void child_list_rm_pid(child_list_t* list, pid_t pid);
 child_list_element_t* child_list_find(child_list_t* list, pid_t pid);
 int child_list_num_running(child_list_t* list);
+void child_list_kill_oldest(child_list_t* list);
 
 int rh_exec(const char* script, char* const argv[], char* const evp[], child_list_t* child_lst, options_t* opt);
 int rh_exec_child(child_list_element_t* child);
-- 
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