From: Yann Droneaud <ydroneaud@opteya.com>
Date: Tue, 16 Jul 2013 21:59:52 +0000 (+0200)
Subject: [librdmacm,8/8] Open files with "close on exec" flag
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=1cde6c1b67cd2750ee47f01325271b4188c3d166;p=~shefty%2Flibrdmacm.git

[librdmacm,8/8] Open files with "close on exec" flag

File opened by librdmacm are not supposed to be inherited across
exec*(), most of the files are of no use for another program, and
others cannot be used without the associated memory mapping.

This patch changes fopen() open() and socket() to always set
close on exec flag.

This patch also add checks to configure to guess if fopen() supports
"e" flag. If O_CLOEXEC and SOCK_CLOEXEC are supported, fopen() should
support "e". If not supported, its discarded according to POSIX. Many
operating systems have support for fopen("e").

You might find more information about close on exec in the following articles:

- "Excuse me son, but your code is leaking !!!" by Dan Walsh
  http://danwalsh.livejournal.com/53603.html

- "Secure File Descriptor Handling" by Ulrich Drepper
  http://udrepper.livejournal.com/20407.html

Note: this patch won't set close on exec flag on file descriptors
created by the kernel for completion channel and such.
This is addressed by another kernel patch.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
---

diff --git a/configure.ac b/configure.ac
index 9fd9e9e6..6163f564 100644
--- a/configure.ac
+++ b/configure.ac
@@ -75,6 +75,30 @@ AC_CHECK_HEADER(infiniband/acm.h,
 		AC_DEFINE(DEFINE_ACM_MSG, 1, [adding ACM message definition]),
 			[#include <infiniband/acm.h>]), [])
 
+dnl Checks close on exec support
+AC_CHECK_HEADERS([fcntl.h sys/socket.h])
+
+AC_CHECK_DECLS([O_CLOEXEC],,[AC_DEFINE([O_CLOEXEC],[0], [Defined to 0 if not provided])],
+[[
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+]])
+AC_CHECK_DECLS([SOCK_CLOEXEC],,[AC_DEFINE([SOCK_CLOEXEC],[0],[Defined to 0 if not provided])],
+[[
+#ifdef HAVE_SYS_SOCKET_H
+# include <sys/socket.h>
+#endif
+]])
+
+AC_CACHE_CHECK(for close on exec modifier for fopen(), ac_cv_feature_stream_cloexec_flag,
+   [if test $ac_cv_have_decl_O_CLOEXEC = yes ; then
+        if test $ac_cv_have_decl_SOCK_CLOEXEC = yes ; then
+            ac_cv_feature_stream_cloexec_flag="e"
+        fi
+    fi])
+AC_DEFINE_UNQUOTED([STREAM_CLOEXEC], "$ac_cv_feature_stream_cloexec_flag", [fopen() modifier for setting close on exec flag])
+
 AC_CACHE_CHECK(whether ld accepts --version-script, ac_cv_version_script,
     if test -n "`$LD --help < /dev/null 2>/dev/null | grep version-script`"; then
         ac_cv_version_script=yes
diff --git a/src/acm.c b/src/acm.c
index c423bb72..dfc49599 100755
--- a/src/acm.c
+++ b/src/acm.c
@@ -79,7 +79,7 @@ static int ucma_set_server_port(void)
 {
 	FILE *f;
 
-	if ((f = fopen("/var/run/ibacm.port", "r"))) {
+	if ((f = fopen("/var/run/ibacm.port", "r" STREAM_CLOEXEC))) {
 		fscanf(f, "%hu", (unsigned short *) &server_port);
 		fclose(f);
 	}
@@ -99,7 +99,7 @@ void ucma_ib_init(void)
 	if (!ucma_set_server_port())
 		goto out;
 
-	sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	sock = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
 	if (sock < 0)
 		goto out;
 
diff --git a/src/cma.c b/src/cma.c
index 2fb9913a..baebecdd 100755
--- a/src/cma.c
+++ b/src/cma.c
@@ -328,7 +328,7 @@ struct rdma_event_channel *rdma_create_event_channel(void)
 	if (!channel)
 		return NULL;
 
-	channel->fd = open("/dev/infiniband/rdma_cm", O_RDWR);
+	channel->fd = open("/dev/infiniband/rdma_cm", O_RDWR | O_CLOEXEC);
 	if (channel->fd < 0) {
 		fprintf(stderr, PFX "Fatal: unable to open /dev/infiniband/rdma_cm\n");
 		goto err;