From 71a1c8a68f31206cf725563e07c225fed8e5727a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= <remi@remlab.net>
Date: Sun, 7 Feb 2010 15:51:35 +0200
Subject: [PATCH] vlc_dup: dup with close-on-exec
---
configure.ac | 2 +-
include/vlc_fs.h | 2 ++
src/libvlccore.sym | 1 +
src/text/filesystem.c | 29 +++++++++++++++++++++++++++++
4 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/configure.ac b/configure.ac
index f3221bc591c7..9c9d9a4e9113 100644
--- a/configure.ac
+++ b/configure.ac
@@ -530,7 +530,7 @@ AC_CHECK_FUNCS(fdatasync,,
])
dnl Check for non-standard system calls
-AC_CHECK_FUNCS([accept4 eventfd fstatfs vmsplice])
+AC_CHECK_FUNCS([accept4 dup3 eventfd fstatfs vmsplice])
AH_BOTTOM([#include <vlc_fixups.h>])
diff --git a/include/vlc_fs.h b/include/vlc_fs.h
index 9f03b1b1ac73..51bfd60c8e44 100644
--- a/include/vlc_fs.h
+++ b/include/vlc_fs.h
@@ -53,4 +53,6 @@ VLC_EXPORT( int, utf8_lstat, ( const char *filename, struct stat *buf ) );
VLC_EXPORT( int, vlc_mkstemp, ( char * ) );
+VLC_EXPORT( int, vlc_dup, ( int ) );
+
#endif
diff --git a/src/libvlccore.sym b/src/libvlccore.sym
index 64466791b7f1..d608ab34dea0 100644
--- a/src/libvlccore.sym
+++ b/src/libvlccore.sym
@@ -440,6 +440,7 @@ vlc_readdir
vlc_scandir
vlc_stat
vlc_unlink
+vlc_dup
utf8_vfprintf
var_AddCallback
var_Change
diff --git a/src/text/filesystem.c b/src/text/filesystem.c
index fdb25fb4f275..6ebfc39a138c 100644
--- a/src/text/filesystem.c
+++ b/src/text/filesystem.c
@@ -535,3 +535,32 @@ int vlc_mkstemp( char *template )
return -1;
}
+/**
+ * Duplicates a file descriptor. The new file descriptor has the close-on-exec
+ * descriptor flag set.
+ * @return a new file descriptor or -1
+ */
+int vlc_dup (int oldfd)
+{
+ int newfd;
+
+#ifdef HAVE_DUP3
+ /* Unfortunately, dup3() works like dup2(), not like plain dup(). So we
+ * need such contortion to find the new file descriptor while preserving
+ * thread safety of the file descriptor table. */
+ newfd = vlc_open ("/dev/null", O_RDONLY);
+ if (likely(newfd != -1))
+ {
+ if (likely(dup3 (oldfd, newfd, O_CLOEXEC) == newfd))
+ return newfd;
+ close (newfd);
+ }
+#endif
+
+ newfd = dup (oldfd);
+#ifdef HAVE_FCNTL
+ if (likely(newfd != -1))
+ fcntl (newfd, F_SETFD, FD_CLOEXEC);
+#endif
+ return newfd;
+}
--
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