refine the max connections, compare the system ulimit max open files, error when exeed limit

@@ -2,6 +2,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
 }
 

@@ -2,6 +2,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 daemon              off;
 srs_log_tank        console;
 http_api {

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              19350;
+max_connections     1000;
 daemon              on;
 srs_log_tank        file;
 srs_log_file        ./objs/srs.demo.19350.log;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 daemon              on;
 srs_log_tank        file;
 srs_log_file        ./objs/srs.demo.log;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     dvr {
         enabled      on;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     dvr {
         enabled      on;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 pid                 objs/edge.pid;
 srs_log_file        ./objs/edge.log;
 vhost __defaultVhost__ {

@@ -2,7 +2,8 @@
 # @see https://github.com/winlinvip/simple-rtmp-server/wiki/DRM
 # @see full.conf for detail config.
 
-listen              1935;
+listen              1935
+max_connections     1000;
 vhost __defaultVhost__ {
     mode            remote;
     origin          127.0.0.1:19350;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     transcode {
         enabled     on;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 pid                 ./objs/srs.master.pid;
 srs_log_tank        file;
 srs_log_file        ./objs/srs.master.log;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              19350;
+max_connections     1000;
 pid                 ./objs/srs.slave.pid;
 srs_log_tank        file;
 srs_log_file        ./objs/srs.slave.log;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     hls {
         enabled         on;

 # the config for srs http heartbeat, report its info to api-server
 # @see full.conf for detail config.
 
-listen              1935;
+listen              1935
+max_connections     1000;
 heartbeat {
     enabled         on;
     interval        9.3;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 http_stream {
     enabled         on;
     listen          8080;

@@ -2,6 +2,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 srs_log_tank        file;
 srs_log_file        ./objs/srs.log;
 vhost __defaultVhost__ {

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     ingest livestream {
         enabled      on;

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              19350;
+max_connections     1000;
 pid                 objs/origin.pid;
 srs_log_file        ./objs/origin.log;
 vhost __defaultVhost__ {

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     gop_cache       off;
     queue_length    10;

@@ -3,5 +3,6 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
 }

@@ -2,6 +2,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 srs_log_tank        file;
 srs_log_file        ./objs/srs.log;
 http_api {

@@ -3,6 +3,7 @@
 # @see full.conf for detail config.
 
 listen              1935;
+max_connections     1000;
 vhost __defaultVhost__ {
     hls {
         enabled         on;

@@ -23,6 +23,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <srs_app_config.hpp>
 
+#include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>
@@ -1405,6 +1406,18 @@ int SrsConfig::check_config()
         return ret;
     }
     
+    // check max connections of system limits
+    if (true) {
+        int max_open_files = sysconf(_SC_OPEN_MAX);
+        if (get_max_connections() > max_open_files) {
+            ret = ERROR_SYSTEM_CONFIG_INVALID;
+            srs_error("invalid max_connections=%d, system limit to %d, ret=%d. "
+                "you can login as root and set the limit: ulimit -HSn %d", get_max_connections(), max_open_files,
+                ret, get_max_connections());
+            return ret;
+        }
+    }
+    
     ////////////////////////////////////////////////////////////////////////
     // check heartbeat
     ////////////////////////////////////////////////////////////////////////

@@ -197,7 +197,9 @@ void SrsFastLog::error(const char* tag, int context_id, const char* fmt, ...)
     va_end(ap);
 
     // add strerror() to error msg.
-    size += snprintf(log_data + size, LOG_MAX_SIZE - size, "(%s)", strerror(errno));
+    if (errno != 0) {
+        size += snprintf(log_data + size, LOG_MAX_SIZE - size, "(%s)", strerror(errno));
+    }
 
     write_log(fd, log_data, size, SrsLogLevel::Error);
 }

@@ -1787,11 +1787,13 @@ VOID TEST(ConfigMainTest, ParseEmpty)
 VOID TEST(ConfigMainTest, ParseMinConf)
 {
     MockSrsConfig conf;
-    EXPECT_TRUE(ERROR_SUCCESS == conf.parse("listen 1935;"));
+    EXPECT_TRUE(ERROR_SUCCESS == conf.parse("listen 1935; max_connections 1000;"));
     
     vector<string> listens = conf.get_listen();
     EXPECT_EQ(1, (int)listens.size());
     EXPECT_STREQ("1935", listens.at(0).c_str());
+    
+    EXPECT_EQ(1000, conf.get_max_connections());
 }
 
 VOID TEST(ConfigMainTest, ParseInvalidDirective)
@@ -4364,3 +4366,94 @@ VOID TEST(ConfigMainTest, CheckConf_listen)
         EXPECT_TRUE(ERROR_SUCCESS != conf.parse("listen -1935;"));
     }
 }
+
+VOID TEST(ConfigMainTest, CheckConf_pid)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("pids ./objs/srs.pid;"));
+    }
+}
+
+VOID TEST(ConfigMainTest, CheckConf_chunk_size)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_sizes 60000;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_size 0;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_size 1;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_size 127;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_size -1;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_size -4096;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("chunk_size 65536;"));
+    }
+}
+
+VOID TEST(ConfigMainTest, CheckConf_ff_log_dir)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("ff_log_dirs ./objs;"));
+    }
+}
+
+VOID TEST(ConfigMainTest, CheckConf_srs_log_level)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("srs_log_levels trace;"));
+    }
+}
+
+VOID TEST(ConfigMainTest, CheckConf_srs_log_file)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("srs_log_files ./objs/srs.log;"));
+    }
+}
+
+VOID TEST(ConfigMainTest, CheckConf_max_connections)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("max_connectionss 1000;"));
+    }
+    
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("max_connections 0;"));
+    }
+}
+
+VOID TEST(ConfigMainTest, CheckConf_)
+{
+    if (true) {
+        MockSrsConfig conf;
+        EXPECT_TRUE(ERROR_SUCCESS != conf.parse("listens 1935;"));
+    }
+}