feat: add InitLimit (#346)

* add InitLimit

src/pikiwidb.cc

@@ -11,6 +11,7 @@
 #include "pikiwidb.h"
 
 #include <sys/fcntl.h>
+#include <sys/resource.h>
 #include <sys/wait.h>
 #include <unistd.h>
 #include <iostream>
@@ -216,6 +217,29 @@ static void InitLogs() {
 #endif
 }
 
+static int InitLimit() {
+  rlimit limit;
+  rlim_t maxfiles = g_config.max_clients;
+  if (getrlimit(RLIMIT_NOFILE, &limit) == -1) {
+    WARN("getrlimit error: {}", strerror(errno));
+  } else if (limit.rlim_cur < maxfiles) {
+    rlim_t old_limit = limit.rlim_cur;
+    limit.rlim_cur = maxfiles;
+    limit.rlim_max = maxfiles;
+    if (setrlimit(RLIMIT_NOFILE, &limit) != -1) {
+      WARN("your 'limit -n ' of {} is not enough for PikiwiDB to start. PikiwiDB have successfully reconfig it to ",
+           old_limit, limit.rlim_cur);
+    } else {
+      ERROR(
+          "your 'limit -n ' of {} is not enough for PikiwiDB to start."
+          " PikiwiDB can not reconfig it({}), do it by yourself",
+          old_limit, strerror(errno));
+      return -1;
+    }
+  }
+  return 0;
+}
+
 static void daemonize() {
   if (fork()) {
     exit(0); /* parent exits */
@@ -258,6 +282,7 @@ int main(int ac, char* av[]) {
     daemonize();
   }
 
+  InitLimit();
   pstd::InitRandom();
   SignalSetup();
   InitLogs();