[bug#75810,v5,01/14] daemon: Use ‘close_range’ where available.
Commit Message
* nix/libutil/util.cc (closeMostFDs) [HAVE_CLOSE_RANGE]: Use
‘close_range’ when ‘exceptions’ is empty.
* config-daemon.ac: Check for <linux/close_range.h> and the
‘close_range’ symbol.
Change-Id: I12fa3bde58b003fcce5ea5a1fee1dcf9a92c0359
---
config-daemon.ac | 5 +++--
nix/libutil/util.cc | 23 +++++++++++++++++------
2 files changed, 20 insertions(+), 8 deletions(-)
@@ -78,7 +78,8 @@ if test "x$guix_build_daemon" = "xyes"; then
dnl Chroot support.
AC_CHECK_FUNCS([chroot unshare])
- AC_CHECK_HEADERS([sched.h sys/param.h sys/mount.h sys/syscall.h])
+ AC_CHECK_HEADERS([sched.h sys/param.h sys/mount.h sys/syscall.h \
+ linux/close_range.h])
if test "x$ac_cv_func_chroot" != "xyes"; then
AC_MSG_ERROR(['chroot' function missing, bailing out])
@@ -95,7 +96,7 @@ if test "x$guix_build_daemon" = "xyes"; then
dnl strsignal: for error reporting.
dnl statx: fine-grain 'stat' call, new in glibc 2.28.
AC_CHECK_FUNCS([lutimes lchown posix_fallocate sched_setaffinity \
- statvfs nanosleep strsignal statx])
+ statvfs nanosleep strsignal statx close_range])
dnl Check for <locale>.
AC_LANG_PUSH(C++)
@@ -23,6 +23,10 @@
#include <sys/prctl.h>
#endif
+#ifdef HAVE_LINUX_CLOSE_RANGE_H
+# include <linux/close_range.h>
+#endif
+
extern char * * environ;
@@ -1087,12 +1091,19 @@ string runProgram(Path program, bool searchPath, const Strings & args)
void closeMostFDs(const set<int> & exceptions)
{
- int maxFD = 0;
- maxFD = sysconf(_SC_OPEN_MAX);
- for (int fd = 0; fd < maxFD; ++fd)
- if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO
- && exceptions.find(fd) == exceptions.end())
- close(fd); /* ignore result */
+#ifdef HAVE_CLOSE_RANGE
+ if (exceptions.empty())
+ close_range(3, ~0U, 0);
+ else
+#endif
+ {
+ int maxFD = 0;
+ maxFD = sysconf(_SC_OPEN_MAX);
+ for (int fd = 0; fd < maxFD; ++fd)
+ if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO
+ && exceptions.find(fd) == exceptions.end())
+ close(fd); /* ignore result */
+ }
}