Conf monitor, Adding inotify non-blocking config file monitoring -n option

include/monitor_conf.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2015 Benoit Masson (yahoo@perenite.com) 
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#ifndef MONITORCONF_H_
+#define MONITORCONF_H_
+
+#include "stdbool.h"
+
+unsigned int monitorConf_init(const char *config_file);
+void monitorConf_close(void);
+bool monitorConf_hasChanged(void);
+
+#endif /* JSON_H_ */

src/Makefile.am

@@ -18,6 +18,7 @@ automatic_SOURCES = \
    $(top_srcdir)/src/file.c           \
    $(top_srcdir)/src/json.c           \
    $(top_srcdir)/src/list.c           \
+   $(top_srcdir)/src/monitor_conf.c   \
    $(top_srcdir)/src/output.c         \
    $(top_srcdir)/src/filters.c        \
    $(top_srcdir)/src/prowl.c          \
@@ -42,6 +43,7 @@ noinst_HEADERS =    \
    $(top_srcdir)/include/file.h           \
    $(top_srcdir)/include/json.h           \
    $(top_srcdir)/include/list.h           \
+   $(top_srcdir)/include/monitor_conf.h   \
    $(top_srcdir)/include/output.h         \
    $(top_srcdir)/include/filters.h        \
    $(top_srcdir)/include/prowl.h          \

src/automatic.c

@@ -60,6 +60,7 @@
 #include "version.h"
 #include "web.h"
 #include "xml_parser.h"
+#include "monitor_conf.h"
 
 PRIVATE char AutoConfigFile[MAXPATHLEN + 1];
 PRIVATE void session_free(auto_handle *as);
@@ -69,17 +70,19 @@ PRIVATE bool closing = false;
 PRIVATE bool nofork  = AM_DEFAULT_NOFORK;
 PRIVATE bool isRunning = false;
 PRIVATE bool seenHUP = false;
+PRIVATE bool monitorConf = false;
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 PRIVATE void usage(void) {
-  printf("usage: automatic [-fh] [-v level] [-l logfile] [-c file]\n"
+  printf("usage: automatic [-fhn] [-v level] [-l logfile] [-c file]\n"
     "\n"
     "Automatic %s\n"
     "\n"
     "  -f --nodeamon             Run in the foreground and log to stderr\n"
     "  -h --help                 Display this message\n"
+    "  -n --config-monitor       Monitor config file changes\n"
     "  -v --verbose <level>      Set output level to <level> (default=1)\n"
     "  -c --configfile <path>    Path to configuration file\n"
     "  -o --once                 Quit Automatic after first check of RSS feeds\n"
@@ -92,20 +95,21 @@ PRIVATE void usage(void) {
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
-PRIVATE void readargs(int argc, char ** argv, char **c_file, char** logfile, char **xmlfile,
+PRIVATE void readargs(int argc, char ** argv, char **c_file, bool * monitorConf, char** logfile, char **xmlfile,
                       bool * nofork, uint8_t * verbose, uint8_t * once, uint8_t * append_log,
                       uint8_t * match_only) {
-  char optstr[] = "afhv:c:l:ox:m";
+  char optstr[] = "anfhv:c:l:ox:m";
   struct option longopts[] = {
-    { "verbose",    required_argument, NULL, 'v' },
-    { "nodaemon",   no_argument,       NULL, 'f' },
-    { "help",       no_argument,       NULL, 'h' },
-    { "configfile", required_argument, NULL, 'c' },
-    { "once",       no_argument,       NULL, 'o' },
-    { "logfile",    required_argument, NULL, 'l' },
-    { "append-log", no_argument,       NULL, 'a' },
-    { "xml",        required_argument, NULL, 'x' },
-    { "match-only", no_argument,       NULL, 'm' },
+    { "verbose",        required_argument, NULL, 'v' },
+    { "nodaemon",       no_argument,       NULL, 'f' },
+    { "help",           no_argument,       NULL, 'h' },
+    { "config-monitor", no_argument,       NULL, 'n' }, 
+    { "configfile",     required_argument, NULL, 'c' },
+    { "once",           no_argument,       NULL, 'o' },
+    { "logfile",        required_argument, NULL, 'l' },
+    { "append-log",     no_argument,       NULL, 'a' },
+    { "xml",            required_argument, NULL, 'x' },
+    { "match-only",     no_argument,       NULL, 'm' },
     { NULL, 0, NULL, 0 } };
   int opt;
 
@@ -120,6 +124,9 @@ PRIVATE void readargs(int argc, char ** argv, char **c_file, char** logfile, cha
       case 'f':
         *nofork = true;
         break;
+      case 'n':
+        *monitorConf = true;
+        break;
       case 'c':
         *c_file = optarg;
         break;
@@ -154,6 +161,7 @@ PRIVATE void shutdown_daemon(auto_handle *as) {
   }
   session_free(as);
   SessionID_free();
+  monitorConf_close();
   log_close();
   exit(EXIT_SUCCESS);
 }
@@ -728,7 +736,7 @@ int main(int argc, char **argv) {
   */
   log_init(NULL, verbose, 0);
 
-  readargs(argc, argv, &config_file, &logfile, &xmlfile, &nofork, &verbose, &once, &append_log, &match_only);
+  readargs(argc, argv, &config_file, &monitorConf, &logfile, &xmlfile, &nofork, &verbose, &once, &append_log, &match_only);
 
   /* reinitialize the logging with the values from the command line */
   log_init(logfile, verbose, append_log);
@@ -770,6 +778,12 @@ int main(int argc, char **argv) {
     dbg_printft( P_MSG, "Daemon started");
   }
 
+  if (monitorConf) {
+    if (monitorConf_init(config_file) != 0) {
+      monitorConf = false; /* avoid testing inotify if not able to initialize */
+    }
+  }
+
   dbg_printf(P_INFO, "verbose level: %d", verbose);
   dbg_printf(P_INFO, "foreground mode: %s", nofork == true ? "yes" : "no");
 
@@ -800,6 +814,11 @@ int main(int argc, char **argv) {
 
     isRunning = false;
 
+    if (monitorConf && monitorConf_hasChanged()) {
+      /* consider a config file change is a SIGHUP signal */
+      seenHUP = true;
+    }
+
     if(seenHUP) {
       signal_handler(SIGHUP);
     }

src/monitor_conf.c

@@ -0,0 +1,125 @@
+/* $Id$
+ * $Name$
+ * $ProjectName$
+ */
+
+/**
+ * @file monitor_conf.c
+ *
+ * Provides output functionality.
+ */
+
+/* Copyright (C) 2015 Benoit Masson (yahoo@perenite.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/inotify.h>
+#include <fcntl.h>
+
+#include "utils.h"
+#include "output.h"
+#include "monitor_conf.h"
+
+#define MAX_EVENTS 1024 /*Max. number of events to process at one go*/
+#define LEN_NAME 16 /*Assuming that the length of the filename won't exceed 16 bytes*/
+#define EVENT_SIZE  ( sizeof (struct inotify_event) ) /*size of one event*/
+#define BUF_LEN     ( MAX_EVENTS * ( EVENT_SIZE + LEN_NAME )) /*buffer to store the data of events*/
+
+PRIVATE int fd = 0;
+PRIVATE int wd = 0;
+PRIVATE char *buffer;
+
+unsigned int monitorConf_init(const char *config_file) {
+
+  /* check fd, wd are null if not close them */
+  if (fd || wd ) {
+    monitorConf_close();
+  }
+
+  dbg_printf(P_DBG, "Monitor Conf init");
+
+  fd = inotify_init();
+  if ( fd < 0 ) {
+    dbg_printf(P_ERROR, "Couldn't initialize inotify");
+    return 1;
+  }
+
+  /* non blocking inotify */
+  if (fcntl (fd, F_SETFL, fcntl (fd, F_GETFL) | O_NONBLOCK) <0 ) {
+    dbg_printf(P_ERROR, "Couldn't initialize non blocking IO inotify");
+    monitorConf_close();
+    return 1;
+  }
+
+  /* add watch to config directory */
+  wd = inotify_add_watch(fd, config_file, IN_CREATE | IN_MODIFY | IN_DELETE);
+
+  if (wd == -1) {
+    dbg_printf(P_ERROR, "Couldn't add watch to %s\n",config_file);
+  } else {
+    dbg_printf(P_MSG, "Watching: %s\n",config_file);
+  }
+
+  /* inititialize buffer for inotify read events */
+  buffer = (char *) malloc(BUF_LEN);
+
+  return 0;
+}
+
+void monitorConf_close(void) {
+  dbg_printf(P_DBG, "Monitor Conf close");
+  if (fd || wd) {
+    inotify_rm_watch(fd, wd);
+  }
+  free(buffer);
+}
+
+bool monitorConf_hasChanged(void) {
+  bool changed = false;
+  struct inotify_event *event = NULL;
+  int length = 0;
+  int i = 0;
+
+  dbg_printf(P_DBG, "Monitor file conf check haschanged");
+
+  if ( fd ) {
+    dbg_printf(P_DBG, "Monitor file conf fd > 0");
+
+    dbg_printf(P_DBG, "Monitor file conf before read");
+    length = read( fd, buffer, BUF_LEN );
+    dbg_printf(P_DBG, "Monitor file conf after read, length:%d", length);
+
+    if (length >0) { /* >0 include both no data & EAGAIN error for non-blocking */
+      while ( i < length ) {
+        event = ( struct inotify_event * ) &buffer[ i ];
+        dbg_printf(P_DBG, "Monitor file conf event->len:%d , event->mask:%d", event->len, event->mask);
+        if ( event->mask & IN_MODIFY) {
+          dbg_printf(P_INFO2, "Monitor file conf MODIFY event detected");
+          changed = true;
+        }
+        i += EVENT_SIZE + event->len;
+      }
+    }
+  }
+
+  dbg_printf(P_DBG, "Monitor file conf check haschanged end"); 
+  return changed;
+}