* Copyright (c) 1996, 1998 The NetBSD Foundation, Inc.

/*-
* Copyright (c) 1996, 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by J.T. Conklin.
*
* Mostly rewritten to be used in Alpine Linux (with musl c-library)
* by Timo Teräs.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <err.h>
#include <errno.h>
#include <values.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

struct conf_variable {
const char *name;
enum { SYSCONF, CONFSTR, PATHCONF, CONSTANT, UCONSTANT, NUM_TYPES } type;
long value;
};

static const struct conf_variable conf_table[] = {
{ "PATH", CONFSTR, _CS_PATH },

/* Utility Limit Minimum Values */
{ "POSIX2_BC_BASE_MAX", CONSTANT, _POSIX2_BC_BASE_MAX },
{ "POSIX2_BC_DIM_MAX", CONSTANT, _POSIX2_BC_DIM_MAX },
{ "POSIX2_BC_SCALE_MAX", CONSTANT, _POSIX2_BC_SCALE_MAX },
{ "POSIX2_BC_STRING_MAX", CONSTANT, _POSIX2_BC_STRING_MAX },
{ "POSIX2_COLL_WEIGHTS_MAX", CONSTANT, _POSIX2_COLL_WEIGHTS_MAX },
{ "POSIX2_EXPR_NEST_MAX", CONSTANT, _POSIX2_EXPR_NEST_MAX },
{ "POSIX2_LINE_MAX", CONSTANT, _POSIX2_LINE_MAX },
{ "POSIX2_RE_DUP_MAX", CONSTANT, _POSIX2_RE_DUP_MAX },
{ "POSIX2_VERSION", CONSTANT, _POSIX2_VERSION },

/* POSIX.1 Minimum Values */
{ "_POSIX_AIO_LISTIO_MAX", CONSTANT, _POSIX_AIO_LISTIO_MAX },
{ "_POSIX_AIO_MAX", CONSTANT, _POSIX_AIO_MAX },
{ "_POSIX_ARG_MAX", CONSTANT, _POSIX_ARG_MAX },
{ "_POSIX_CHILD_MAX", CONSTANT, _POSIX_CHILD_MAX },
{ "_POSIX_LINK_MAX", CONSTANT, _POSIX_LINK_MAX },
{ "_POSIX_MAX_CANON", CONSTANT, _POSIX_MAX_CANON },
{ "_POSIX_MAX_INPUT", CONSTANT, _POSIX_MAX_INPUT },
{ "_POSIX_MQ_OPEN_MAX", CONSTANT, _POSIX_MQ_OPEN_MAX },
{ "_POSIX_MQ_PRIO_MAX", CONSTANT, _POSIX_MQ_PRIO_MAX },
{ "_POSIX_NAME_MAX", CONSTANT, _POSIX_NAME_MAX },
{ "_POSIX_NGROUPS_MAX", CONSTANT, _POSIX_NGROUPS_MAX },
{ "_POSIX_OPEN_MAX", CONSTANT, _POSIX_OPEN_MAX },
{ "_POSIX_PATH_MAX", CONSTANT, _POSIX_PATH_MAX },
{ "_POSIX_PIPE_BUF", CONSTANT, _POSIX_PIPE_BUF },
{ "_POSIX_SSIZE_MAX", CONSTANT, _POSIX_SSIZE_MAX },
{ "_POSIX_STREAM_MAX", CONSTANT, _POSIX_STREAM_MAX },
{ "_POSIX_TZNAME_MAX", CONSTANT, _POSIX_TZNAME_MAX },

/* Symbolic Utility Limits */
{ "BC_BASE_MAX", SYSCONF, _SC_BC_BASE_MAX },
{ "BC_DIM_MAX", SYSCONF, _SC_BC_DIM_MAX },
{ "BC_SCALE_MAX", SYSCONF, _SC_BC_SCALE_MAX },
{ "BC_STRING_MAX", SYSCONF, _SC_BC_STRING_MAX },
{ "COLL_WEIGHTS_MAX", SYSCONF, _SC_COLL_WEIGHTS_MAX },
{ "EXPR_NEST_MAX", SYSCONF, _SC_EXPR_NEST_MAX },
{ "LINE_MAX", SYSCONF, _SC_LINE_MAX },
{ "RE_DUP_MAX", SYSCONF, _SC_RE_DUP_MAX },

/* Optional Facility Configuration Values */
{ "_POSIX2_C_BIND", SYSCONF, _SC_2_C_BIND },
{ "POSIX2_C_DEV", SYSCONF, _SC_2_C_DEV },
{ "POSIX2_CHAR_TERM", SYSCONF, _SC_2_CHAR_TERM },
{ "POSIX2_FORT_DEV", SYSCONF, _SC_2_FORT_DEV },
{ "POSIX2_FORT_RUN", SYSCONF, _SC_2_FORT_RUN },
{ "POSIX2_LOCALEDEF", SYSCONF, _SC_2_LOCALEDEF },
{ "POSIX2_SW_DEV", SYSCONF, _SC_2_SW_DEV },
{ "POSIX2_UPE", SYSCONF, _SC_2_UPE },

/* POSIX.1 Configurable System Variables */
{ "AIO_LISTIO_MAX", SYSCONF, _SC_AIO_LISTIO_MAX },
{ "AIO_MAX", SYSCONF, _SC_AIO_MAX },
{ "ARG_MAX", SYSCONF, _SC_ARG_MAX },
{ "CHILD_MAX", SYSCONF, _SC_CHILD_MAX },
{ "CLK_TCK", SYSCONF, _SC_CLK_TCK },
{ "MQ_OPEN_MAX", SYSCONF, _SC_MQ_OPEN_MAX },
{ "MQ_PRIO_MAX", SYSCONF, _SC_MQ_PRIO_MAX },
{ "NGROUPS_MAX", SYSCONF, _SC_NGROUPS_MAX },
{ "OPEN_MAX", SYSCONF, _SC_OPEN_MAX },
{ "STREAM_MAX", SYSCONF, _SC_STREAM_MAX },
{ "TZNAME_MAX", SYSCONF, _SC_TZNAME_MAX },
{ "_POSIX_JOB_CONTROL", SYSCONF, _SC_JOB_CONTROL },
{ "_POSIX_SAVED_IDS", SYSCONF, _SC_SAVED_IDS },
{ "_POSIX_VERSION", SYSCONF, _SC_VERSION },

{ "LINK_MAX", PATHCONF, _PC_LINK_MAX },
{ "MAX_CANON", PATHCONF, _PC_MAX_CANON },
{ "MAX_INPUT", PATHCONF, _PC_MAX_INPUT },
{ "NAME_MAX", PATHCONF, _PC_NAME_MAX },
{ "PATH_MAX", PATHCONF, _PC_PATH_MAX },
{ "PIPE_BUF", PATHCONF, _PC_PIPE_BUF },
{ "_POSIX_CHOWN_RESTRICTED", PATHCONF, _PC_CHOWN_RESTRICTED },
{ "_POSIX_NO_TRUNC", PATHCONF, _PC_NO_TRUNC },
{ "_POSIX_VDISABLE", PATHCONF, _PC_VDISABLE },

/* POSIX.1b Configurable System Variables */
{ "PAGESIZE", SYSCONF, _SC_PAGESIZE },
{ "_POSIX_ASYNCHRONOUS_IO", SYSCONF, _SC_ASYNCHRONOUS_IO },
{ "_POSIX_FSYNC", SYSCONF, _SC_FSYNC },
{ "_POSIX_MAPPED_FILES", SYSCONF, _SC_MAPPED_FILES },
{ "_POSIX_MEMLOCK", SYSCONF, _SC_MEMLOCK },
{ "_POSIX_MEMLOCK_RANGE", SYSCONF, _SC_MEMLOCK_RANGE },
{ "_POSIX_MEMORY_PROTECTION", SYSCONF, _SC_MEMORY_PROTECTION },
{ "_POSIX_MESSAGE_PASSING", SYSCONF, _SC_MESSAGE_PASSING },
{ "_POSIX_MONOTONIC_CLOCK", SYSCONF, _SC_MONOTONIC_CLOCK },
{ "_POSIX_PRIORITY_SCHEDULING", SYSCONF, _SC_PRIORITY_SCHEDULING },
{ "_POSIX_SEMAPHORES", SYSCONF, _SC_SEMAPHORES },
{ "_POSIX_SHARED_MEMORY_OBJECTS", SYSCONF, _SC_SHARED_MEMORY_OBJECTS },
{ "_POSIX_SYNCHRONIZED_IO", SYSCONF, _SC_SYNCHRONIZED_IO },
{ "_POSIX_TIMERS", SYSCONF, _SC_TIMERS },

{ "_POSIX_SYNC_IO", PATHCONF, _PC_SYNC_IO },

/* POSIX.1c Configurable System Variables */
{ "LOGIN_NAME_MAX", SYSCONF, _SC_LOGIN_NAME_MAX },
{ "_POSIX_THREADS", SYSCONF, _SC_THREADS },

/* POSIX.1j Configurable System Variables */
{ "_POSIX_BARRIERS", SYSCONF, _SC_BARRIERS },
{ "_POSIX_READER_WRITER_LOCKS", SYSCONF, _SC_READER_WRITER_LOCKS },
{ "_POSIX_SPIN_LOCKS", SYSCONF, _SC_SPIN_LOCKS },

/* XPG4.2 Configurable System Variables */
{ "IOV_MAX", SYSCONF, _SC_IOV_MAX },
{ "PAGE_SIZE", SYSCONF, _SC_PAGE_SIZE },
{ "_XOPEN_SHM", SYSCONF, _SC_XOPEN_SHM },

/* X/Open CAE Spec. Issue 5 Version 2 Configurable System Variables */
{ "FILESIZEBITS", PATHCONF, _PC_FILESIZEBITS },

/* POSIX.1-2001 XSI Option Group Configurable System Variables */
{ "ATEXIT_MAX", SYSCONF, _SC_ATEXIT_MAX },

/* POSIX.1-2001 TSF Configurable System Variables */
{ "GETGR_R_SIZE_MAX", SYSCONF, _SC_GETGR_R_SIZE_MAX },
{ "GETPW_R_SIZE_MAX", SYSCONF, _SC_GETPW_R_SIZE_MAX },

/* Commonly provided extensions */
{ "_PHYS_PAGES", SYSCONF, _SC_PHYS_PAGES },
{ "_AVPHYS_PAGES", SYSCONF, _SC_AVPHYS_PAGES },
{ "_NPROCESSORS_CONF", SYSCONF, _SC_NPROCESSORS_CONF },
{ "_NPROCESSORS_ONLN", SYSCONF, _SC_NPROCESSORS_ONLN },

/* Data type related extensions */
{ "CHAR_BIT", CONSTANT, CHAR_BIT },
{ "CHAR_MAX", CONSTANT, CHAR_MAX },
{ "CHAR_MIN", CONSTANT, CHAR_MIN },
{ "INT_MAX", CONSTANT, INT_MAX },
{ "INT_MIN", CONSTANT, INT_MIN },
{ "LONG_BIT", CONSTANT, LONG_BIT },
{ "LONG_MAX", CONSTANT, LONG_MAX },
{ "LONG_MIN", CONSTANT, LONG_MIN },
{ "SCHAR_MAX", CONSTANT, SCHAR_MAX },
{ "SCHAR_MIN", CONSTANT, SCHAR_MIN },
{ "SHRT_MAX", CONSTANT, SHRT_MAX },
{ "SHRT_MIN", CONSTANT, SHRT_MIN },
{ "SSIZE_MAX", CONSTANT, SSIZE_MAX },
{ "UCHAR_MAX", UCONSTANT, (long) UCHAR_MAX },
{ "UINT_MAX", UCONSTANT, (long) UINT_MAX },
{ "ULONG_MAX", UCONSTANT, (long) ULONG_MAX },
{ "USHRT_MAX", UCONSTANT, (long) USHRT_MAX },
{ "WORD_BIT", CONSTANT, WORD_BIT },

{ NULL, CONSTANT, 0L }
};

static int all = 0;

static void usage(const char *p)
{
(void)fprintf(stderr, "Usage: %s system_var\n\t%s -a\n"
"\t%s path_var pathname\n\t%s -a pathname\n", p, p, p, p);
exit(EXIT_FAILURE);
}

static void print_long(const char *name, long val)
{
if (all) printf("%s = %ld\n", name, val);
else printf("%ld\n", val);
}

static void print_ulong(const char *name, unsigned long val)
{
if (all) printf("%s = %lu\n", name, val);
else printf("%lu\n", val);
}

static void print_string(const char *name, const char *val)
{
if (all) printf("%s = %s\n", name, val);
else printf("%s\n", val);
}

static int print_constant(const struct conf_variable *cp, const char *pathname)
{
print_long(cp->name, cp->value);
return 0;
}

static int print_uconstant(const struct conf_variable *cp, const char *pathname)
{
print_ulong(cp->name, (unsigned long) cp->value);
return 0;
}

static int print_sysconf(const struct conf_variable *cp, const char *pathname)
{
long val;

errno = 0;
if ((val = sysconf((int)cp->value)) == -1) {
if (errno != 0) err(EXIT_FAILURE, "sysconf(%ld)", cp->value);
return -1;
}
print_long(cp->name, val);
return 0;
}

static int print_confstr(const struct conf_variable *cp, const char *pathname)
{
size_t len;
char *val;

errno = 0;
if ((len = confstr((int)cp->value, NULL, 0)) == 0) goto error;
if ((val = malloc(len)) == NULL) err(EXIT_FAILURE, "Can't allocate %zu bytes", len);
errno = 0;
if (confstr((int)cp->value, val, len) == 0) goto error;
print_string(cp->name, val);
free(val);
return 0;
error:
if (errno != EINVAL) err(EXIT_FAILURE, "confstr(%ld)", cp->value);
return -1;
}

static int print_pathconf(const struct conf_variable *cp, const char *pathname)
{
long val;

errno = 0;
if ((val = pathconf(pathname, (int)cp->value)) == -1) {
if (all && errno == EINVAL) return 0;
if (errno != 0) err(EXIT_FAILURE, "pathconf(%s, %ld)", pathname, cp->value);
return -1;
}
print_long(cp->name, val);
return 0;
}

typedef int (*handler_t)(const struct conf_variable *cp, const char *pathname);
static const handler_t type_handlers[NUM_TYPES] = {
[SYSCONF] = print_sysconf,
[CONFSTR] = print_confstr,
[PATHCONF] = print_pathconf,
[CONSTANT] = print_constant,
[UCONSTANT] = print_uconstant,
};

int main(int argc, char **argv)
{
const char *progname = argv[0];
const struct conf_variable *cp;
const char *varname, *pathname;
int ch, found = 0;

(void)setlocale(LC_ALL, "");
while ((ch = getopt(argc, argv, "a")) != -1) {
switch (ch) {
case 'a':
all = 1;
break;
case '?':
default:
usage(progname);
}
}
argc -= optind;
argv += optind;

if (!all) {
if (argc == 0)
usage(progname);
varname = argv[0];
argc--;
argv++;
} else
varname = NULL;

if (argc > 1)
usage(progname);
pathname = argv[0]; /* may be NULL */

for (cp = conf_table; cp->name != NULL; cp++) {
if (!all && strcmp(varname, cp->name) != 0) continue;
if ((cp->type == PATHCONF) == (pathname != NULL)) {
if (type_handlers[cp->type](cp, pathname) < 0)
print_string(cp->name, "undefined");
found = 1;
} else if (!all)
errx(EXIT_FAILURE, "%s: invalid variable type", cp->name);
}
if (!all && !found) errx(EXIT_FAILURE, "%s: unknown variable", varname);
(void)fflush(stdout);
return ferror(stdout) ? EXIT_FAILURE : EXIT_SUCCESS;
}