From d79c5cfba3eb6354f5c2391e8c53aebf4c906ba2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Canna=C3=B2?= <rene.cannao@gmail.com>
Date: Wed, 14 Jun 2023 09:56:45 +0000
Subject: [PATCH] Close fd after fork() also on REST API

Closing the file descriptors also on REST API after the fork.
It excludes all the pipes.
close_all_non_term_fd() accepts a vector of FDs to exclude
---
 include/proxysql_utils.h |  5 +++++
 lib/ProxySQL_Admin.cpp   | 19 +------------------
 lib/proxysql_utils.cpp   | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/include/proxysql_utils.h b/include/proxysql_utils.h
index 2d75c4693..eb510357a 100644
--- a/include/proxysql_utils.h
+++ b/include/proxysql_utils.h
@@ -7,6 +7,9 @@
 #include <string>
 #include <vector>
 #include <sys/time.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/resource.h>
 
 #ifndef ETIME
 // ETIME is not defined on FreeBSD
@@ -205,4 +208,6 @@ std::string replace_str(const std::string& str, const std::string& match, const
 
 
 std::string generate_multi_rows_query(int rows, int params);
+
+void close_all_non_term_fd(std::vector<int> excludeFDs);
 #endif
diff --git a/lib/ProxySQL_Admin.cpp b/lib/ProxySQL_Admin.cpp
index b5a0aca9b..5e46ffc16 100644
--- a/lib/ProxySQL_Admin.cpp
+++ b/lib/ProxySQL_Admin.cpp
@@ -189,23 +189,6 @@ static char * load_file (const char *filename) {
 */
 
 
-void close_all_non_term_fd() {
-	DIR *d;
-	struct dirent *dir;
-	d = opendir("/proc/self/fd");
-	if (d) {
-		while ((dir = readdir(d)) != NULL) {
-			if (strlen(dir->d_name) && dir->d_name[0] != '.') {
-				int fd = std::stol(std::string(dir->d_name));
-				if (fd > 2) {
-					close(fd);
-				}
-			}
-		}
-		closedir(d);
-	}
-}
-
 static int round_intv_to_time_interval(int& intv) {
 	if (intv > 300) {
 		intv = 600;
@@ -13620,7 +13603,7 @@ unsigned long long ProxySQL_External_Scheduler::run_once() {
 					exit(EXIT_FAILURE);
 				}
 				if (cpid == 0) {
-					close_all_non_term_fd();
+					close_all_non_term_fd({});
 					char *newenviron[] = { NULL };
 					int rc;
 					rc=execve(sr->filename, newargs, newenviron);
diff --git a/lib/proxysql_utils.cpp b/lib/proxysql_utils.cpp
index 1207a04ef..3f1eddf5e 100644
--- a/lib/proxysql_utils.cpp
+++ b/lib/proxysql_utils.cpp
@@ -239,6 +239,9 @@ int wexecvp(
 		// Duplicate file argument to avoid manual duplication
 		_argv.insert(_argv.begin(), file.c_str());
 
+		// close all files , with the exception of the pipes
+		close_all_non_term_fd({ CHILD_READ_FD, CHILD_WRITE_FD, CHILD_WRITE_ERR, PARENT_READ_FD, PARENT_READ_ERR, PARENT_WRITE_FD});
+
 		// Copy the pipe descriptors
 		int dup_read_err = dup2(CHILD_READ_FD, STDIN_FILENO);
 		int dup_write_err = dup2(CHILD_WRITE_FD, STDOUT_FILENO);
@@ -257,6 +260,7 @@ int wexecvp(
 		close(PARENT_READ_ERR);
 		close(PARENT_WRITE_FD);
 
+
 		char** args = const_cast<char**>(_argv.data());
 		child_err = execvp(file.c_str(), args);
 
@@ -397,3 +401,32 @@ std::string generate_multi_rows_query(int rows, int params) {
 	}
 	return s;
 }
+
+void close_all_non_term_fd(std::vector<int> excludeFDs) {
+	DIR *d;
+	struct dirent *dir;
+	d = opendir("/proc/self/fd");
+	if (d) {
+		while ((dir = readdir(d)) != NULL) {
+			if (strlen(dir->d_name) && dir->d_name[0] != '.') {
+				int fd = std::stol(std::string(dir->d_name));
+				if (fd > 2) {
+					if (std::find(excludeFDs.begin(), excludeFDs.end(), fd) == excludeFDs.end()) {
+						close(fd);
+					}
+				}
+			}
+		}
+		closedir(d);
+	} else {
+		struct rlimit nlimit;
+		int rc = getrlimit(RLIMIT_NOFILE, &nlimit);
+		if (rc == 0) {
+			for (unsigned int fd = 3; fd < nlimit.rlim_cur; fd++) {
+				if (std::find(excludeFDs.begin(), excludeFDs.end(), fd) == excludeFDs.end()) {
+					close(fd);
+				}
+			}
+		}
+	}
+}