[Libguestfs] [libnbd PATCH v3 08/29] lib/utils: add unit test for async-signal-safe assert()

Don't try to test async-signal-safety, only that NBD_INTERNAL_FORK_SAFE_ASSERT() works similarly to assert(): - it prints diagnostics to stderr, - it calls abort(). Some unfortunate gymnastics are necessary to avoid littering the system with unwanted core dumps. Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- configure.ac | 5 ++ lib/test-fork-safe-assert.c | 63 ++++++++++++++++++++ lib/Makefile.am | 38 ++++++++++-- lib/test-fork-safe-assert.sh | 31 ++++++++++ .gitignore | 2 + 5 files changed, 135 insertions(+), 4 deletions(-) diff --git a/configure.ac b/configure.ac index 893e82ac6fea..3549188ec5fb 100644 --- a/configure.ac +++ b/configure.ac @@ -129,11 +129,16 @@ dnl Check for various libc functions, all optional. dnl dnl posix_fadvise helps to optimise linear reads and writes. dnl +dnl When /proc/sys/kernel/core_pattern starts with a pipe (|) symbol, Linux +dnl ignores "ulimit -c" and (equivalent) setrlimit(RLIMIT_CORE) actions, for +dnl disabling core dumping. Only prctl() can be used then, for that purpose. +dnl dnl strerrordesc_np (glibc only) is preferred over sys_errlist: dnl https://lists.fedoraproject.org/archives/list/glibc@lists.fedoraproject.o... AC_CHECK_FUNCS([\ posix_fadvise \ posix_memalign \ + prctl \ strerrordesc_np \ valloc]) diff --git a/lib/test-fork-safe-assert.c b/lib/test-fork-safe-assert.c new file mode 100644 index 000000000000..131cbaa0abca --- /dev/null +++ b/lib/test-fork-safe-assert.c @@ -0,0 +1,63 @@ +/* nbd client library in userspace + * Copyright (C) 2013-2023 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#ifdef HAVE_PRCTL +#include <sys/prctl.h> +#endif +#include <sys/resource.h> + +#undef NDEBUG + +#include "internal.h" + +#define TRUE 1 +#define FALSE 0 + +int +main (void) +{ + struct rlimit rlimit; + + /* The standard approach for disabling core dumping. Has no effect on Linux if + * /proc/sys/kernel/core_pattern starts with a pipe (|) symbol. + */ + if (getrlimit (RLIMIT_CORE, &rlimit) == -1) { + perror ("getrlimit"); + return EXIT_FAILURE; + } + rlimit.rlim_cur = 0; + if (setrlimit (RLIMIT_CORE, &rlimit) == -1) { + perror ("setrlimit"); + return EXIT_FAILURE; + } + +#ifdef HAVE_PRCTL + if (prctl (PR_SET_DUMPABLE, 0, 0, 0, 0) == -1) { + perror ("prctl"); + return EXIT_FAILURE; + } +#endif + + NBD_INTERNAL_FORK_SAFE_ASSERT (TRUE); + NBD_INTERNAL_FORK_SAFE_ASSERT (FALSE); + return 0; +} diff --git a/lib/Makefile.am b/lib/Makefile.am index ece50770326e..1f6501ceb49a 100644 --- a/lib/Makefile.am +++ b/lib/Makefile.am @@ -25,15 +25,30 @@ generator_built = \ unlocked.h \ $(NULL) +CLEANFILES += \ + test-fork-safe-assert.err \ + $(NULL) + EXTRA_DIST = \ $(generator_built) \ libnbd.syms \ + test-fork-safe-assert.sh \ $(NULL) lib_LTLIBRARIES = libnbd.la BUILT_SOURCES = $(generator_built) +AM_CPPFLAGS = \ + -I$(top_srcdir)/include \ + -I$(top_srcdir)/common/include \ + -I$(top_srcdir)/common/utils \ + $(NULL) + +AM_CFLAGS = \ + $(WARNINGS_CFLAGS) \ + $(NULL) + libnbd_la_SOURCES = \ aio.c \ api.c \ @@ -60,13 +75,11 @@ libnbd_la_SOURCES = \ utils.c \ $(NULL) libnbd_la_CPPFLAGS = \ - -I$(top_srcdir)/include \ - -I$(top_srcdir)/common/include \ - -I$(top_srcdir)/common/utils \ + $(AM_CPPFLAGS) \ -Dsysconfdir=\"$(sysconfdir)\" \ $(NULL) libnbd_la_CFLAGS = \ - $(WARNINGS_CFLAGS) \ + $(AM_CFLAGS) \ $(PTHREAD_CFLAGS) \ $(GNUTLS_CFLAGS) \ $(LIBXML2_CFLAGS) \ @@ -86,3 +99,20 @@ libnbd_la_LDFLAGS = \ pkgconfigdir = $(libdir)/pkgconfig pkgconfig_DATA = libnbd.pc + +# Unit tests. + +TESTS = \ + test-fork-safe-assert.sh \ + $(NULL) + +check_PROGRAMS = \ + test-fork-safe-assert \ + $(NULL) + +test_fork_safe_assert_SOURCES = \ + $(top_srcdir)/common/utils/vector.c \ + errors.c \ + test-fork-safe-assert.c \ + utils.c \ + $(NULL) diff --git a/lib/test-fork-safe-assert.sh b/lib/test-fork-safe-assert.sh new file mode 100755 index 000000000000..88fc553b484d --- /dev/null +++ b/lib/test-fork-safe-assert.sh @@ -0,0 +1,31 @@ +#!/usr/bin/env bash +# nbd client library in userspace +# Copyright (C) 2013-2023 Red Hat Inc. +# +# This library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2 of the License, or (at your option) any later version. +# +# This library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with this library; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + +set +e + +./test-fork-safe-assert 2>test-fork-safe-assert.err +exit_status=$? + +set -e + +test $exit_status -gt 128 +signal_name=$(kill -l $exit_status) +test "x$signal_name" = xABRT || test "x$signal_name" = xSIGABRT + +ptrn="^test-fork-safe-assert\\.c:[0-9]+: main: Assertion \`FALSE' failed\\.\$" +grep -E -q -- "$ptrn" test-fork-safe-assert.err diff --git a/.gitignore b/.gitignore index f42737131d8c..cd27a4ed7557 100644 --- a/.gitignore +++ b/.gitignore @@ -124,6 +124,8 @@ Makefile.in /lib/states-run.c /lib/states.c /lib/states.h +/lib/test-fork-safe-assert +/lib/test-fork-safe-assert.err /lib/unlocked.h /libtool /ltmain.sh