2 files changed, 55 insertions, 0 deletions
diff --git a/src/util/os_file.c b/src/util/os_file.c
index f02d74afd2c..c5970ddb243 100644
--- a/src/util/os_file.c
+++ b/src/util/os_file.c
@@ -18,6 +18,11 @@
 #define O_CREAT _O_CREAT
 #define O_EXCL _O_EXCL
 #define O_WRONLY _O_WRONLY
+#else
+#include <unistd.h>
+#ifndef F_DUPFD_CLOEXEC
+#define F_DUPFD_CLOEXEC 1030
+#endif
 #endif
 
 
@@ -31,6 +36,50 @@ os_file_create_unique(const char *filename, int filemode)
 }
 
 
+#if DETECT_OS_WINDOWS
+int
+os_dupfd_cloexec(int fd)
+{
+   /*
+    * On Windows child processes don't inherit handles by default:
+    * https://devblogs.microsoft.com/oldnewthing/20111216-00/?p=8873
+    */
+   return dup(fd);
+}
+#else
+int
+os_dupfd_cloexec(int fd)
+{
+   int minfd = 3;
+   int newfd = fcntl(fd, F_DUPFD_CLOEXEC, minfd);
+
+   if (newfd >= 0)
+      return newfd;
+
+   if (errno != EINVAL)
+      return -1;
+
+   newfd = fcntl(fd, F_DUPFD, minfd);
+
+   if (newfd < 0)
+      return -1;
+
+   long flags = fcntl(newfd, F_GETFD);
+   if (flags == -1) {
+      close(newfd);
+      return -1;
+   }
+
+   if (fcntl(newfd, F_SETFD, flags | FD_CLOEXEC) == -1) {
+      close(newfd);
+      return -1;
+   }
+
+   return newfd;
+}
+#endif
+
+
 #if DETECT_OS_LINUX
 
 #include <fcntl.h>
diff --git a/src/util/os_file.h b/src/util/os_file.h
index 36f367ea358..cf0dc207595 100644
--- a/src/util/os_file.h
+++ b/src/util/os_file.h
@@ -25,6 +25,12 @@ FILE *
 os_file_create_unique(const char *filename, int filemode);
 
 /*
+ * Duplicate a file descriptor, making sure not to keep it open after an exec*()
+ */
+int
+os_dupfd_cloexec(int fd);
+
+/*
  * Read a file.
  * Returns a char* that the caller must free(), or NULL and sets errno.
  * If size is not null and no error occured it's set to the size of the