Hi Dmitry, > Yes, it is reliable as it mirrors > for (fd = 0; fd < 20; fd++) > piece of code in tests/test-execute-child.c file.
Ah, I had missed that. Thanks. > there could > be other external sources of inherited descriptors, so the test should > rather be robust and make sure these external sources do not affect the > test. Yes, KDE/plasma and NetBSD are such external sources of inherited descriptors. > I'd choose a simple close() rather than a bit more complex cloexec if > tests/test-execute-child.c did not contain this uncommented hunk: > for (fd = 0; fd < 20; fd++) > #ifdef __NetBSD__ > if (fd != 3) > #endif > > If for some reason __NetBSD__ is allowed to have descriptor #3 inherited, > then it shouldn't be closed in tests/test-execute-main.c either. That was just my first attempt at working around the issue. It occurred first on NetBSD. > > 4) How about other environments? I saw 'test-execute.sh' also fail in > > some recent Linux distro with KDE desktop. Apparently 'plasma' is passing > > one or two open file descriptors to all children (that is, to all processes > > running in this desktop environment). Do you think this is worth reporting? > > If it isn't documented, then I'd say it's a bug, please report it. Will do. > > If so, Gnulib should probably provide a substitute close_range(), and > > test-execute-main.c should better call this function, rather than rolling > > its own loop. > > Yes, I think it makes sense to provide this API in gnulib, although it > won't be able to address all issues the syscall is intended to address. I now read from [1] comment 23: "The close_range seems a sensible addition to added as a syscall wrapper for Linux, without any extra fallback, and returning ENOSYS on older kernel (as for copy_file_range)." So, Gnulib would have to provide a function that invokes close_range AND has fallback code. (That is general philosophy of Gnulib: provide easily usable functions, rather than very low-level bricks that require extensive manpage consultation before use.) [1] https://sourceware.org/bugzilla/show_bug.cgi?id=10353 I'm applying this fix: 2021-04-07 Bruno Haible <br...@clisp.org> execute tests: Avoid test failure in certain environments. Reported by Dmitry V. Levin <l...@altlinux.org> in <https://lists.gnu.org/archive/html/bug-gnulib/2021-04/msg00082.html>. * tests/test-execute-main.c (main): Close file descriptors 3..19. * tests/test-execute-child.c (main): Remove NetBSD workaround. * modules/execute-tests (configure.ac): Test for close_range function. diff --git a/modules/execute-tests b/modules/execute-tests index 422c1ab..c942130 100644 --- a/modules/execute-tests +++ b/modules/execute-tests @@ -18,6 +18,8 @@ stdint unistd configure.ac: +dnl Test for Linux system call close_range(), declared in <unistd.h>. +AC_CHECK_FUNCS([close_range]) Makefile.am: TESTS += test-execute.sh diff --git a/tests/test-execute-child.c b/tests/test-execute-child.c index c3a1190..dbaae1e 100644 --- a/tests/test-execute-child.c +++ b/tests/test-execute-child.c @@ -171,14 +171,11 @@ main (int argc, char *argv[]) char *p = buf; int fd; for (fd = 0; fd < 20; fd++) - #ifdef __NetBSD__ - if (fd != 3) - #endif - if (is_open (fd)) - { - sprintf (p, "%d ", fd); - p += strlen (p); - } + if (is_open (fd)) + { + sprintf (p, "%d ", fd); + p += strlen (p); + } const char *expected = (test < 16 ? "0 1 2 10 " : "0 1 2 "); if (strcmp (buf, expected) == 0) return 0; diff --git a/tests/test-execute-main.c b/tests/test-execute-main.c index 39e24af..944dcd1 100644 --- a/tests/test-execute-main.c +++ b/tests/test-execute-main.c @@ -58,6 +58,31 @@ main (int argc, char *argv[]) char *prog_path = argv[1]; const char *progname = "test-execute-child"; int test = atoi (argv[2]); + + switch (test) + { + case 14: + case 15: + case 16: + /* Close file descriptors that have been inherited from the parent + process and that would cause failures in test-execute-child.c. + Such file descriptors have been seen: + - with GNU make, when invoked as 'make -j N' with j > 1, + - in some versions of the KDE desktop environment, + - on NetBSD. + */ + #if HAVE_CLOSE_RANGE + if (close_range (3, 20 - 1, 0) < 0) + #endif + { + int fd; + for (fd = 3; fd < 20; fd++) + close (fd); + } + default: + break; + } + switch (test) { case 0:
