From cc9efe948e97e8f6f785bdd2e37a17ba0cce672d Mon Sep 17 00:00:00 2001
From: Adam Dickmeiss <adam@indexdata.dk>
Date: Thu, 15 Oct 2015 11:44:01 +0200
Subject: [PATCH] First work on usage limit

---
 configure.ac     |    4 ++--
 src/connection.c |   17 +++++++++++++----
 src/eventl.c     |   31 +++++++++++++++++++++++++++----
 src/eventl.h     |    2 +-
 4 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/configure.ac b/configure.ac
index 85ef2db..be9d6b1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -11,7 +11,7 @@ m4_esyscmd([. ./IDMETA; echo $VERSION|tr -d '\n']),
 
 AC_CONFIG_HEADERS(src/config.h)
 
-AC_CONFIG_SRCDIR([configure.ac]) 
+AC_CONFIG_SRCDIR([configure.ac])
 AC_CONFIG_AUX_DIR([config])
 AC_CANONICAL_SYSTEM
 
@@ -48,7 +48,7 @@ if test "$checkBoth" = "1"; then
     AC_CHECK_FUNC([accept], , [LIBS=$oldLibs])
 fi
 AC_CHECK_FUNC([gethostbyname], ,[AC_CHECK_LIB(nsl, main, [LIBS="$LIBS -lnsl"])])
-AC_CHECK_FUNCS([getaddrinfo mallinfo])
+AC_CHECK_FUNCS([getaddrinfo mallinfo getrlimit])
 
 if test -d ${srcdir}/.git; then
 	sha=`git show --pretty=format:%H|head -1`
diff --git a/src/connection.c b/src/connection.c
index 98a73e0..c2c4bea 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -333,6 +333,7 @@ static int connection_connect(struct connection *con, iochan_man_t iochan_man)
     const char *sru;
     const char *sru_version = 0;
     const char *value;
+    int r = 0;
     WRBUF w;
 
     struct session_database *sdb = client_get_database(con->client);
@@ -423,12 +424,20 @@ static int connection_connect(struct connection *con, iochan_man_t iochan_man)
     con->state = Conn_Connecting;
     iochan_settimeout(con->iochan, con->operation_timeout);
     iochan_setdata(con->iochan, con);
-    iochan_add(iochan_man, con->iochan);
-
-    client_set_state(con->client, Client_Connecting);
+    if (iochan_add(iochan_man, con->iochan))
+    {
+        yaz_log(YLOG_FATAL, "Out of connections");
+        ZOOM_connection_destroy(con->link);
+        con->link = 0;
+        r = -1;
+    }
+    else
+    {
+        client_set_state(con->client, Client_Connecting);
+    }
     ZOOM_options_destroy(zoptions);
     wrbuf_destroy(w);
-    return 0;
+    return r;
 }
 
 // Ensure that client has a connection associated
diff --git a/src/eventl.c b/src/eventl.c
index 40dfeb4..da2f7f9 100644
--- a/src/eventl.c
+++ b/src/eventl.c
@@ -50,6 +50,7 @@
 #include <yaz/xmalloc.h>
 #include <yaz/mutex.h>
 #include <yaz/poll.h>
+#include <sys/resource.h>
 #include "eventl.h"
 #include "sel_thread.h"
 
@@ -103,6 +104,7 @@ struct iochan_man_s {
     int log_level;
     YAZ_MUTEX iochan_mutex;
     int size_fds;
+    int limit_fd;
     struct yaz_poll_fd *fds;
 };
 
@@ -117,6 +119,16 @@ iochan_man_t iochan_man_create(int no_threads)
     man->iochan_mutex = 0;
     man->size_fds = 0;
     man->fds = 0;
+    man->limit_fd = 0;
+#if HAVE_GETRLIMIT
+    {
+        struct rlimit limit_data;
+        getrlimit(RLIMIT_NOFILE, &limit_data);
+        yaz_log(YLOG_LOG, "getrlimit NOFILE cur=%ld max=%ld",
+                (long) limit_data.rlim_cur, (long) limit_data.rlim_max);
+        man->limit_fd = limit_data.rlim_cur - 200;
+    }
+#endif
     yaz_mutex_create(&man->iochan_mutex);
     return man;
 }
@@ -152,15 +164,26 @@ void iochan_man_destroy(iochan_man_t *mp)
     }
 }
 
-void iochan_add(iochan_man_t man, IOCHAN chan)
+int iochan_add(iochan_man_t man, IOCHAN chan)
 {
+    int r = 0, no_fds = 0;
+    IOCHAN p;
     chan->man = man;
-    yaz_mutex_enter(man->iochan_mutex);
+
     yaz_log(man->log_level, "iochan_add : chan=%p channel list=%p", chan,
             man->channel_list);
-    chan->next = man->channel_list;
-    man->channel_list = chan;
+    yaz_mutex_enter(man->iochan_mutex);
+    for (p = man->channel_list; p; p = p->next)
+        no_fds++;
+    if (man->limit_fd > 0 && no_fds >= man->limit_fd)
+        r = -1;
+    else
+    {
+        chan->next = man->channel_list;
+        man->channel_list = chan;
+    }
     yaz_mutex_leave(man->iochan_mutex);
+    return r;
 }
 
 IOCHAN iochan_create(int fd, IOC_CALLBACK cb, int flags, const char *name)
diff --git a/src/eventl.h b/src/eventl.h
index 92f9a53..392b000 100644
--- a/src/eventl.h
+++ b/src/eventl.h
@@ -52,7 +52,7 @@ typedef struct iochan
 
 
 iochan_man_t iochan_man_create(int no_threads);
-void iochan_add(iochan_man_t man, IOCHAN chan);
+int iochan_add(iochan_man_t man, IOCHAN chan);
 void iochan_man_events(iochan_man_t man);
 void iochan_man_destroy(iochan_man_t *mp);
 
-- 
1.7.10.4