From 1ff6c67a252e59488a26e3c8f6690b29ef56e369 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 4 Jul 2017 16:12:46 +0200 Subject: sysconf: Use conservative default for _SC_NPROCESSORS_ONLN [BZ #21542] --- ChangeLog | 8 +++ posix/Makefile | 3 +- posix/tst-sysconf-empty-chroot.c | 95 +++++++++++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/getsysstats.c | 5 +- 4 files changed, 109 insertions(+), 2 deletions(-) create mode 100644 posix/tst-sysconf-empty-chroot.c diff --git a/ChangeLog b/ChangeLog index e8af883..314c69f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,13 @@ 2017-07-04 Florian Weimer + [BZ #21542] + * sysdeps/unix/sysv/linux/getsysstats.c (__get_nprocs): Default to + two if no accurate information is available. + * posix/tst-sysconf-empty-chroot.c: New file. + * posix/Makefile (tests): Add it. + +2017-07-04 Florian Weimer + * resolv/resolv_conf.c (resolv_conf_matches): Tighten check for name server and sort list counts. Fix improper check for empty search path (completely missing domain name) leading to assertion failure diff --git a/posix/Makefile b/posix/Makefile index 1c328b8..33abcae 100644 --- a/posix/Makefile +++ b/posix/Makefile @@ -92,7 +92,8 @@ tests := test-errno tstgetopt testfnm runtests runptests \ tst-pathconf tst-getaddrinfo4 tst-rxspencer-no-utf8 \ tst-fnmatch3 bug-regex36 tst-getaddrinfo5 \ tst-posix_spawn-fd tst-posix_spawn-setsid \ - tst-posix_fadvise tst-posix_fadvise64 + tst-posix_fadvise tst-posix_fadvise64 \ + tst-sysconf-empty-chroot tests-internal := bug-regex5 bug-regex20 bug-regex33 \ tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3 xtests := bug-ga2 diff --git a/posix/tst-sysconf-empty-chroot.c b/posix/tst-sysconf-empty-chroot.c new file mode 100644 index 0000000..dd3b94b --- /dev/null +++ b/posix/tst-sysconf-empty-chroot.c @@ -0,0 +1,95 @@ +/* Test sysconf with an empty chroot. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C 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 2.1 of the License, or (at your option) any later version. + + The GNU C 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 the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Check for an SMP system in a forked process, so that the parent + process does not cache the value. */ +static void +is_smp_callback (void *closure) +{ + bool *result = closure; + + long cpus = sysconf (_SC_NPROCESSORS_ONLN); + TEST_VERIFY_EXIT (cpus > 0); + *result = cpus != 1; +} + +static bool +is_smp (void) +{ + bool *result = support_shared_allocate (sizeof (*result)); + support_isolate_in_subprocess (is_smp_callback, result); + bool result_copy = *result; + support_shared_free (result); + return result_copy; +} + +static char *path_chroot; + +/* Prepare an empty directory, to be used as a chroot. */ +static void +prepare (int argc, char **argv) +{ + path_chroot = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir); + if (mkdtemp (path_chroot) == NULL) + FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", path_chroot); + add_temp_file (path_chroot); +} + +/* The actual test. Run it in a subprocess, so that the test harness + can remove the temporary directory in --direct mode. */ +static void +chroot_callback (void *closure) +{ + xchroot (path_chroot); + long cpus = sysconf (_SC_NPROCESSORS_ONLN); + printf ("info: sysconf (_SC_NPROCESSORS_ONLN) in chroot: %ld\n", cpus); + TEST_VERIFY (cpus > 0); + TEST_VERIFY (cpus != 1); + _exit (0); +} + +static int +do_test (void) +{ + if (!is_smp ()) + { + printf ("warning: test not supported on uniprocessor system\n"); + return EXIT_UNSUPPORTED; + } + + support_become_root (); + if (!support_can_chroot ()) + return EXIT_UNSUPPORTED; + + support_isolate_in_subprocess (chroot_callback, NULL); + + return 0; +} + +#define PREPARE prepare +#include diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c index 63e4110..a0dd6eb 100644 --- a/sysdeps/unix/sysv/linux/getsysstats.c +++ b/sysdeps/unix/sysv/linux/getsysstats.c @@ -188,7 +188,10 @@ __get_nprocs (void) cp = buffer_end; re = buffer_end; - result = 1; + + /* Default to an SMP system in case we cannot obtain an accurate + number. */ + result = 2; /* The /proc/stat format is more uniform, use it by default. */ fd = open_not_cancel_2 ("/proc/stat", flags); -- cgit v1.1