[PATCH v2] posix: Fix getconf symbolic constants defined in limits.h (BZ# 29147)
Yury Khrustalev
yury.khrustalev@arm.com
Mon Dec 8 15:44:07 GMT 2025
* Adhemerval
On Wed, Dec 03, 2025 at 01:37:27PM -0300, Adhemerval Zanella wrote:
> From: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
>
> POSIX-1.2018 defines that getconf utility shall print symbolic constant
> listed under the heading Maximum value and Minimum Values [1], however
> current behaviour is to print the values using pathconf or sysconf,
> which represents the specific implementation values instead of the
> system agnostics ones.
>
> Another issue is for such the symbolic constants, getconf handles them
> as a path_var which requires an additional pathname (which does not
> make sense for constants values).
>
> The patch fixes it adding a new internal type, LIMITS_H, which only
> prints the constant symbolic without requiring an additional path.
> Only the values define in glibc provided limits.h plust the GNU
> extensions are handled.
>
> Checked on x86_64-linux-gnu.
>
> [1] https://pubs.opengroup.org/onlinepubs/9699919799/utilities/getconf.html)
> ---
> posix/Makefile | 15 ++++++-
> posix/getconf.c | 86 +++++++++++++++++++++++++++++--------
> posix/tst-getconf-limits.py | 72 +++++++++++++++++++++++++++++++
> 3 files changed, 155 insertions(+), 18 deletions(-)
> create mode 100755 posix/tst-getconf-limits.py
>
> diff --git a/posix/Makefile b/posix/Makefile
> index f6421e5379..490e89f7b8 100644
> --- a/posix/Makefile
> +++ b/posix/Makefile
> @@ -476,7 +476,10 @@ endif
> # XXX Please note that for now we ignore the result of this test.
> tests-special += $(objpfx)annexc.out
> ifeq ($(run-built-tests),yes)
> -tests-special += $(objpfx)tst-getconf.out
> +tests-special += \
> + $(objpfx)tst-getconf.out \
> + $(objpfx)tst-getconf-limits.out \
This upsets lint-makefiles, it seems that it expect order
$(objpfx)tst-getconf-limits.out \
$(objpfx)tst-getconf.out \
Otherwise tests pass on AArch64.
> + # tests-special
> ifeq (yes,$(build-shared))
> ifneq ($(PERL),no)
> tests-special += \
> @@ -729,6 +732,16 @@ $(objpfx)tst-getconf.out: tst-getconf.sh $(objpfx)getconf
> $(SHELL) $< $(common-objpfx) '$(built-program-cmd)'; \
> $(evaluate-test)
>
> +$(objpfx)tst-getconf-limits.out: tst-getconf-limits.py $(objpfx)getconf
> + PYTHONPATH=../scripts \
> + $(PYTHON) tst-getconf-limits.py \
> + --cc="$(CC) $(patsubst -DMODULE_NAME=%, \
> + -DMODULE_NAME=testsuite, \
> + $(CPPFLAGS)) -D_ISOMAC" \
> + '$(built-program-cmd)' \
> + < /dev/null > $@ 2>&1; $(evaluate-test)
> +
> +
> $(objpfx)bug-ga2-mem.out: $(objpfx)bug-ga2.out
> { test -r $(objpfx)bug-ga2.mtrace \
> || ( echo "bug-ga2.mtrace does not exist"; exit 77; ) \
> diff --git a/posix/getconf.c b/posix/getconf.c
> index 4ba9c0dee8..9bee1badf3 100644
> --- a/posix/getconf.c
> +++ b/posix/getconf.c
> @@ -49,24 +49,18 @@
> struct conf
> {
> const char *name;
> - const int call_name;
> - const enum { SYSCONF, CONFSTR, PATHCONF } call;
> + const long int call_name;
> + const enum { SYSCONF, CONFSTR, PATHCONF, LIMITS_H } call;
> };
>
> static const struct conf vars[] =
> {
> { "LINK_MAX", _PC_LINK_MAX, PATHCONF },
> - { "_POSIX_LINK_MAX", _PC_LINK_MAX, PATHCONF },
> { "MAX_CANON", _PC_MAX_CANON, PATHCONF },
> - { "_POSIX_MAX_CANON", _PC_MAX_CANON, PATHCONF },
> { "MAX_INPUT", _PC_MAX_INPUT, PATHCONF },
> - { "_POSIX_MAX_INPUT", _PC_MAX_INPUT, PATHCONF },
> { "NAME_MAX", _PC_NAME_MAX, PATHCONF },
> - { "_POSIX_NAME_MAX", _PC_NAME_MAX, PATHCONF },
> { "PATH_MAX", _PC_PATH_MAX, PATHCONF },
> - { "_POSIX_PATH_MAX", _PC_PATH_MAX, PATHCONF },
> { "PIPE_BUF", _PC_PIPE_BUF, PATHCONF },
> - { "_POSIX_PIPE_BUF", _PC_PIPE_BUF, PATHCONF },
> { "SOCK_MAXBUF", _PC_SOCK_MAXBUF, PATHCONF },
> { "_POSIX_ASYNC_IO", _PC_ASYNC_IO, PATHCONF },
> { "_POSIX_CHOWN_RESTRICTED", _PC_CHOWN_RESTRICTED, PATHCONF },
> @@ -125,9 +119,7 @@ static const struct conf vars[] =
> { "_NPROCESSORS_ONLN", _SC_NPROCESSORS_ONLN, SYSCONF },
> { "NPROCESSORS_ONLN", _SC_NPROCESSORS_ONLN, SYSCONF },
> { "_PHYS_PAGES", _SC_PHYS_PAGES, SYSCONF },
> - { "_POSIX_ARG_MAX", _SC_ARG_MAX, SYSCONF },
> { "_POSIX_ASYNCHRONOUS_IO", _SC_ASYNCHRONOUS_IO, SYSCONF },
> - { "_POSIX_CHILD_MAX", _SC_CHILD_MAX, SYSCONF },
> { "_POSIX_FSYNC", _SC_FSYNC, SYSCONF },
> { "_POSIX_JOB_CONTROL", _SC_JOB_CONTROL, SYSCONF },
> { "_POSIX_MAPPED_FILES", _SC_MAPPED_FILES, SYSCONF },
> @@ -135,8 +127,6 @@ static const struct conf vars[] =
> { "_POSIX_MEMLOCK_RANGE", _SC_MEMLOCK_RANGE, SYSCONF },
> { "_POSIX_MEMORY_PROTECTION", _SC_MEMORY_PROTECTION, SYSCONF },
> { "_POSIX_MESSAGE_PASSING", _SC_MESSAGE_PASSING, SYSCONF },
> - { "_POSIX_NGROUPS_MAX", _SC_NGROUPS_MAX, SYSCONF },
> - { "_POSIX_OPEN_MAX", _SC_OPEN_MAX, SYSCONF },
> { "_POSIX_PII", _SC_PII, SYSCONF },
> { "_POSIX_PII_INTERNET", _SC_PII_INTERNET, SYSCONF },
> { "_POSIX_PII_INTERNET_DGRAM", _SC_PII_INTERNET_DGRAM, SYSCONF },
> @@ -155,8 +145,6 @@ static const struct conf vars[] =
> { "_POSIX_SELECT", _SC_SELECT, SYSCONF },
> { "_POSIX_SEMAPHORES", _SC_SEMAPHORES, SYSCONF },
> { "_POSIX_SHARED_MEMORY_OBJECTS", _SC_SHARED_MEMORY_OBJECTS, SYSCONF },
> - { "_POSIX_SSIZE_MAX", _SC_SSIZE_MAX, SYSCONF },
> - { "_POSIX_STREAM_MAX", _SC_STREAM_MAX, SYSCONF },
> { "_POSIX_SYNCHRONIZED_IO", _SC_SYNCHRONIZED_IO, SYSCONF },
> { "_POSIX_THREADS", _SC_THREADS, SYSCONF },
> { "_POSIX_THREAD_ATTR_STACKADDR", _SC_THREAD_ATTR_STACKADDR, SYSCONF },
> @@ -172,7 +160,6 @@ static const struct conf vars[] =
> { "_POSIX_THREAD_SAFE_FUNCTIONS", _SC_THREAD_SAFE_FUNCTIONS, SYSCONF },
> { "_POSIX_TIMERS", _SC_TIMERS, SYSCONF },
> { "TIMER_MAX", _SC_TIMER_MAX, SYSCONF },
> - { "_POSIX_TZNAME_MAX", _SC_TZNAME_MAX, SYSCONF },
> { "_POSIX_VERSION", _SC_VERSION, SYSCONF },
> { "_T_IOV_MAX", _SC_T_IOV_MAX, SYSCONF },
> { "_XOPEN_CRYPT", _SC_XOPEN_CRYPT, SYSCONF },
> @@ -209,7 +196,6 @@ static const struct conf vars[] =
> { "POSIX2_EXPR_NEST_MAX", _SC_EXPR_NEST_MAX, SYSCONF },
> { "POSIX2_FORT_DEV", _SC_2_FORT_DEV, SYSCONF },
> { "POSIX2_FORT_RUN", _SC_2_FORT_RUN, SYSCONF },
> - { "_POSIX2_LINE_MAX", _SC_LINE_MAX, SYSCONF },
> { "POSIX2_LINE_MAX", _SC_LINE_MAX, SYSCONF },
> { "POSIX2_LOCALEDEF", _SC_2_LOCALEDEF, SYSCONF },
> { "POSIX2_RE_DUP_MAX", _SC_RE_DUP_MAX, SYSCONF },
> @@ -405,6 +391,63 @@ static const struct conf vars[] =
> { "_POSIX_IPV6", _SC_IPV6, SYSCONF },
> { "_POSIX_RAW_SOCKETS", _SC_RAW_SOCKETS, SYSCONF },
OK
> + /* limits.h symbolic constants. */
> +#define DEF_LIMIT_H(name) { #name, name, LIMITS_H }
> + /* Maximum Values. */
> + DEF_LIMIT_H (_POSIX_CLOCKRES_MIN),
> +
> + /* Minimum Values. */
> + DEF_LIMIT_H (_POSIX_AIO_LISTIO_MAX),
> + DEF_LIMIT_H (_POSIX_AIO_MAX),
> + DEF_LIMIT_H (_POSIX_ARG_MAX),
> + DEF_LIMIT_H (_POSIX_CHILD_MAX),
> + DEF_LIMIT_H (_POSIX_DELAYTIMER_MAX),
> + DEF_LIMIT_H (_POSIX_HOST_NAME_MAX),
> + DEF_LIMIT_H (_POSIX_LINK_MAX),
> + DEF_LIMIT_H (_POSIX_LOGIN_NAME_MAX),
> + DEF_LIMIT_H (_POSIX_MAX_CANON),
> + DEF_LIMIT_H (_POSIX_MAX_INPUT),
> + DEF_LIMIT_H (_POSIX_MQ_OPEN_MAX),
> + DEF_LIMIT_H (_POSIX_MQ_PRIO_MAX),
> + DEF_LIMIT_H (_POSIX_NAME_MAX),
> + DEF_LIMIT_H (_POSIX_NGROUPS_MAX),
> + DEF_LIMIT_H (_POSIX_OPEN_MAX),
> + DEF_LIMIT_H (_POSIX_PATH_MAX),
> + DEF_LIMIT_H (_POSIX_PIPE_BUF),
> + DEF_LIMIT_H (_POSIX_RE_DUP_MAX),
> + DEF_LIMIT_H (_POSIX_RTSIG_MAX),
> + DEF_LIMIT_H (_POSIX_SEM_NSEMS_MAX),
> + DEF_LIMIT_H (_POSIX_SEM_VALUE_MAX),
> + DEF_LIMIT_H (_POSIX_SIGQUEUE_MAX),
> + DEF_LIMIT_H (_POSIX_SSIZE_MAX),
> + DEF_LIMIT_H (_POSIX_STREAM_MAX),
> + DEF_LIMIT_H (_POSIX_SYMLINK_MAX),
> + DEF_LIMIT_H (_POSIX_SYMLOOP_MAX),
> + DEF_LIMIT_H (_POSIX_THREAD_DESTRUCTOR_ITERATIONS),
> + DEF_LIMIT_H (_POSIX_THREAD_KEYS_MAX),
> + DEF_LIMIT_H (_POSIX_THREAD_THREADS_MAX),
> + DEF_LIMIT_H (_POSIX_TIMER_MAX),
> + DEF_LIMIT_H (_POSIX_TTY_NAME_MAX),
> + DEF_LIMIT_H (_POSIX_TZNAME_MAX),
> +
> + DEF_LIMIT_H (_POSIX2_BC_BASE_MAX),
> + DEF_LIMIT_H (_POSIX2_BC_DIM_MAX),
> + DEF_LIMIT_H (_POSIX2_BC_SCALE_MAX),
> + DEF_LIMIT_H (_POSIX2_BC_STRING_MAX),
> + DEF_LIMIT_H (_POSIX2_CHARCLASS_NAME_MAX),
> + DEF_LIMIT_H (_POSIX2_COLL_WEIGHTS_MAX),
> + DEF_LIMIT_H (_POSIX2_EXPR_NEST_MAX),
> + DEF_LIMIT_H (_POSIX2_LINE_MAX),
> + DEF_LIMIT_H (_POSIX2_RE_DUP_MAX),
> +
> + DEF_LIMIT_H (_XOPEN_IOV_MAX),
> +
> + /* GNU extensions. */
> + DEF_LIMIT_H (_POSIX_FD_SETSIZE),
> + DEF_LIMIT_H (_POSIX_HIWAT),
> + DEF_LIMIT_H (_POSIX_QLIMIT),
> + DEF_LIMIT_H (_POSIX_UIO_MAXIOV),
> +
OK
> { NULL, 0, SYSCONF }
> };
>
> @@ -432,7 +475,7 @@ print_all (const char *path)
> long int value;
> char *cvalue;
> for (c = vars; c->name != NULL; ++c) {
> - printf("%-35s", c->name);
> + printf("%-36s", c->name);
I suppose there are no formatting requirements so we can widen the
column here?
> switch (c->call) {
> case PATHCONF:
> value = pathconf (path, c->call_name);
> @@ -463,6 +506,9 @@ print_all (const char *path)
> printf ("%.*s\n", (int) clen, cvalue);
> free (cvalue);
> break;
> + case LIMITS_H:
> + printf ("%ld\n", c->call_name);
> + break;
> }
> }
> exit (0);
> @@ -703,6 +749,12 @@ environment SPEC.\n\n"));
>
> printf ("%.*s\n", (int) clen, cvalue);
> exit (0);
> +
> + case LIMITS_H:
> + if (argc - ai > 1)
> + usage ();
Requesting a value from limits.h with a path is now an error. This was
discussed in the BZ [1]. Is it OK if an existing script using getconf
with a path on the command line start failing?
> + printf ("%ld\n", c->call_name);
> + exit (0);
> }
> }
>
> diff --git a/posix/tst-getconf-limits.py b/posix/tst-getconf-limits.py
> new file mode 100755
> index 0000000000..e0db1619e1
> --- /dev/null
> +++ b/posix/tst-getconf-limits.py
> @@ -0,0 +1,72 @@
> +#!/usr/bin/python3
> +#
> +# Test if getconf returns the symbolic constants defined in limits.h.
> +# Copyright (C) 2025 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
> +# <https://www.gnu.org/licenses/>.
> +
> +import argparse
> +import glibcextract
> +import re
Nit: the re module is unused.
> +import subprocess
> +import sys
> +
> +
> +def parse_getconf(cmd):
> + getconf_out = subprocess.run(cmd + ['-a'], stdout=subprocess.PIPE,
> + check=True, universal_newlines=True).stdout
> + getconf_set = {}
> + for line in getconf_out.splitlines():
> + fields = line.split()
> + if len(fields) == 2:
> + getconf_set[fields[0]] = fields[1]
> + return getconf_set
> +
> +
> +def main():
> + """The main entry point."""
> + parser = argparse.ArgumentParser(
> + description='Test if getconf returns the symbolic constants defined '
> + 'in limits.h.')
> + parser.add_argument('--cc', metavar='CC',
> + help='C compiler (including options) to use')
> + parser.add_argument('cmd',
> + help='How to run getconf')
> + args = parser.parse_args()
> +
> + ctes = glibcextract.compute_macro_consts(
> + source_text='#include <limits.h>\n',
> + cc=args.cc,
> + macro_re='_POSIX.*',
> + exclude_re='_POSIX_C_SOURCE|_POSIX_SOURCE')
> +
> + getconf_ctes = parse_getconf (args.cmd.split())
> +
> + ret = 0
> + for cte,value in ctes.items():
> + if cte in getconf_ctes:
> + if getconf_ctes[cte] != value:
> + print('Symbol {} is defined as {} on limits.h but getconf shows {}'
> + .format(cte, value, getconf_ctes[cte]))
> + ret = 1;
Nit: unnecessary semi-colon
> + else:
> + print('Symbol {} not presented in getconf'.format(cte))
> + ret = 1;
Nit: same as above
> + sys.exit(ret)
> +
> +
> +if __name__ == '__main__':
> + main()
> --
> 2.43.0
>
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