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      1 /*	$NetBSD: getconf.c,v 1.38 2024/07/22 21:03:17 rillig Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1996, 1998 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by J.T. Conklin.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: getconf.c,v 1.38 2024/07/22 21:03:17 rillig Exp $");
     34 
     35 #include <err.h>
     36 #include <errno.h>
     37 #include <limits.h>
     38 #include <locale.h>
     39 #include <stdio.h>
     40 #include <stdlib.h>
     41 #include <unistd.h>
     42 #include <string.h>
     43 
     44 struct conf_variable
     45 {
     46   const char *name;
     47   enum { SYSCONF, CONFSTR, PATHCONF, CONSTANT } type;
     48   long value;
     49 };
     50 
     51 static void print_longvar(const char *, long);
     52 static void print_strvar(const char *, const char *);
     53 static void printvar(const struct conf_variable *, const char *);
     54 static void usage(void) __dead;
     55 
     56 static const struct conf_variable conf_table[] =
     57 {
     58   { "PATH",			CONFSTR,	_CS_PATH		},
     59 
     60   /* Utility Limit Minimum Values */
     61   { "POSIX2_BC_BASE_MAX",	CONSTANT,	_POSIX2_BC_BASE_MAX	},
     62   { "POSIX2_BC_DIM_MAX",	CONSTANT,	_POSIX2_BC_DIM_MAX	},
     63   { "POSIX2_BC_SCALE_MAX",	CONSTANT,	_POSIX2_BC_SCALE_MAX	},
     64   { "POSIX2_BC_STRING_MAX",	CONSTANT,	_POSIX2_BC_STRING_MAX	},
     65   { "POSIX2_COLL_WEIGHTS_MAX",	CONSTANT,	_POSIX2_COLL_WEIGHTS_MAX },
     66   { "POSIX2_EXPR_NEST_MAX",	CONSTANT,	_POSIX2_EXPR_NEST_MAX	},
     67   { "POSIX2_LINE_MAX",		CONSTANT,	_POSIX2_LINE_MAX	},
     68   { "POSIX2_RE_DUP_MAX",	CONSTANT,	_POSIX2_RE_DUP_MAX	},
     69   { "POSIX2_VERSION",		CONSTANT,	_POSIX2_VERSION		},
     70 
     71   /* POSIX.1 Minimum Values */
     72   { "_POSIX_AIO_LISTIO_MAX",	CONSTANT,	_POSIX_AIO_LISTIO_MAX	},
     73   { "_POSIX_AIO_MAX",		CONSTANT,       _POSIX_AIO_MAX		},
     74   { "_POSIX_ARG_MAX",		CONSTANT,	_POSIX_ARG_MAX		},
     75   { "_POSIX_CHILD_MAX",		CONSTANT,	_POSIX_CHILD_MAX	},
     76   { "_POSIX_LINK_MAX",		CONSTANT,	_POSIX_LINK_MAX		},
     77   { "_POSIX_MAX_CANON",		CONSTANT,	_POSIX_MAX_CANON	},
     78   { "_POSIX_MAX_INPUT",		CONSTANT,	_POSIX_MAX_INPUT	},
     79   { "_POSIX_MQ_OPEN_MAX",	CONSTANT,	_POSIX_MQ_OPEN_MAX	},
     80   { "_POSIX_MQ_PRIO_MAX",	CONSTANT,	_POSIX_MQ_PRIO_MAX	},
     81   { "_POSIX_NAME_MAX",		CONSTANT,	_POSIX_NAME_MAX		},
     82   { "_POSIX_NGROUPS_MAX",	CONSTANT,	_POSIX_NGROUPS_MAX	},
     83   { "_POSIX_OPEN_MAX",		CONSTANT,	_POSIX_OPEN_MAX		},
     84   { "_POSIX_PATH_MAX",		CONSTANT,	_POSIX_PATH_MAX		},
     85   { "_POSIX_PIPE_BUF",		CONSTANT,	_POSIX_PIPE_BUF		},
     86   { "_POSIX_SSIZE_MAX",		CONSTANT,	_POSIX_SSIZE_MAX	},
     87   { "_POSIX_STREAM_MAX",	CONSTANT,	_POSIX_STREAM_MAX	},
     88   { "_POSIX_TZNAME_MAX",	CONSTANT,	_POSIX_TZNAME_MAX	},
     89 
     90   /* Symbolic Utility Limits */
     91   { "BC_BASE_MAX",		SYSCONF,	_SC_BC_BASE_MAX		},
     92   { "BC_DIM_MAX",		SYSCONF,	_SC_BC_DIM_MAX		},
     93   { "BC_SCALE_MAX",		SYSCONF,	_SC_BC_SCALE_MAX	},
     94   { "BC_STRING_MAX",		SYSCONF,	_SC_BC_STRING_MAX	},
     95   { "COLL_WEIGHTS_MAX",		SYSCONF,	_SC_COLL_WEIGHTS_MAX	},
     96   { "EXPR_NEST_MAX",		SYSCONF,	_SC_EXPR_NEST_MAX	},
     97   { "LINE_MAX",			SYSCONF,	_SC_LINE_MAX		},
     98   { "RE_DUP_MAX",		SYSCONF,	_SC_RE_DUP_MAX		},
     99 
    100   /* Optional Facility Configuration Values */
    101   { "_POSIX2_C_BIND",		SYSCONF,	_SC_2_C_BIND		},
    102   { "POSIX2_C_DEV",		SYSCONF,	_SC_2_C_DEV		},
    103   { "POSIX2_CHAR_TERM",		SYSCONF,	_SC_2_CHAR_TERM		},
    104   { "POSIX2_FORT_DEV",		SYSCONF,	_SC_2_FORT_DEV		},
    105   { "POSIX2_FORT_RUN",		SYSCONF,	_SC_2_FORT_RUN		},
    106   { "POSIX2_LOCALEDEF",		SYSCONF,	_SC_2_LOCALEDEF		},
    107   { "POSIX2_SW_DEV",		SYSCONF,	_SC_2_SW_DEV		},
    108   { "POSIX2_UPE",		SYSCONF,	_SC_2_UPE		},
    109 
    110   /* POSIX.1 Configurable System Variables */
    111   { "AIO_LISTIO_MAX",		SYSCONF,	_SC_AIO_LISTIO_MAX	},
    112   { "AIO_MAX",			SYSCONF,	_SC_AIO_MAX		},
    113   { "ARG_MAX",			SYSCONF,	_SC_ARG_MAX 		},
    114   { "CHILD_MAX",		SYSCONF,	_SC_CHILD_MAX		},
    115   { "CLK_TCK",			SYSCONF,	_SC_CLK_TCK		},
    116   { "MQ_OPEN_MAX",		SYSCONF,	_SC_MQ_OPEN_MAX		},
    117   { "MQ_PRIO_MAX",		SYSCONF,	_SC_MQ_PRIO_MAX		},
    118   { "NGROUPS_MAX",		SYSCONF,	_SC_NGROUPS_MAX		},
    119   { "OPEN_MAX",			SYSCONF,	_SC_OPEN_MAX		},
    120   { "STREAM_MAX",		SYSCONF,	_SC_STREAM_MAX		},
    121   { "TZNAME_MAX",		SYSCONF,	_SC_TZNAME_MAX		},
    122   { "_POSIX_JOB_CONTROL",	SYSCONF,	_SC_JOB_CONTROL 	},
    123   { "_POSIX_SAVED_IDS",		SYSCONF,	_SC_SAVED_IDS		},
    124   { "_POSIX_VERSION",		SYSCONF,	_SC_VERSION		},
    125 
    126   { "LINK_MAX",			PATHCONF,	_PC_LINK_MAX		},
    127   { "MAX_CANON",		PATHCONF,	_PC_MAX_CANON		},
    128   { "MAX_INPUT",		PATHCONF,	_PC_MAX_INPUT		},
    129   { "NAME_MAX",			PATHCONF,	_PC_NAME_MAX		},
    130   { "PATH_MAX",			PATHCONF,	_PC_PATH_MAX		},
    131   { "PIPE_BUF",			PATHCONF,	_PC_PIPE_BUF		},
    132   { "_POSIX_CHOWN_RESTRICTED",	PATHCONF,	_PC_CHOWN_RESTRICTED	},
    133   { "_POSIX_NO_TRUNC",		PATHCONF,	_PC_NO_TRUNC		},
    134   { "_POSIX_VDISABLE",		PATHCONF,	_PC_VDISABLE		},
    135 
    136   /* POSIX.1b Configurable System Variables */
    137   { "PAGESIZE",			SYSCONF,	_SC_PAGESIZE		},
    138   { "_POSIX_ASYNCHRONOUS_IO",	SYSCONF,	_SC_ASYNCHRONOUS_IO	},
    139   { "_POSIX_FSYNC",		SYSCONF,	_SC_FSYNC		},
    140   { "_POSIX_MAPPED_FILES",	SYSCONF,	_SC_MAPPED_FILES	},
    141   { "_POSIX_MEMLOCK",		SYSCONF,	_SC_MEMLOCK		},
    142   { "_POSIX_MEMLOCK_RANGE",	SYSCONF,	_SC_MEMLOCK_RANGE	},
    143   { "_POSIX_MEMORY_PROTECTION",	SYSCONF,	_SC_MEMORY_PROTECTION	},
    144   { "_POSIX_MESSAGE_PASSING",	SYSCONF,	_SC_MESSAGE_PASSING	},
    145   { "_POSIX_MONOTONIC_CLOCK",	SYSCONF,	_SC_MONOTONIC_CLOCK	},
    146   { "_POSIX_PRIORITY_SCHEDULING", SYSCONF,	_SC_PRIORITY_SCHEDULING },
    147   { "_POSIX_SEMAPHORES",	SYSCONF,	_SC_SEMAPHORES		},
    148   { "_POSIX_SHARED_MEMORY_OBJECTS", SYSCONF,	_SC_SHARED_MEMORY_OBJECTS },
    149   { "_POSIX_SYNCHRONIZED_IO",	SYSCONF,	_SC_SYNCHRONIZED_IO	},
    150   { "_POSIX_TIMERS",		SYSCONF,	_SC_TIMERS		},
    151 
    152   { "_POSIX_SYNC_IO",		PATHCONF,	_PC_SYNC_IO		},
    153 
    154   /* POSIX.1c Configurable System Variables */
    155   { "LOGIN_NAME_MAX",		SYSCONF,	_SC_LOGIN_NAME_MAX	},
    156   { "_POSIX_THREADS",		SYSCONF,	_SC_THREADS		},
    157 
    158   /* POSIX.1j Configurable System Variables */
    159   { "_POSIX_BARRIERS",		SYSCONF,	_SC_BARRIERS		},
    160   { "_POSIX_READER_WRITER_LOCKS", SYSCONF,	_SC_READER_WRITER_LOCKS	},
    161   { "_POSIX_SPIN_LOCKS",	SYSCONF,	_SC_SPIN_LOCKS		},
    162 
    163   /* XPG4.2 Configurable System Variables */
    164   { "IOV_MAX",			SYSCONF,	_SC_IOV_MAX		},
    165   { "PAGE_SIZE",		SYSCONF,	_SC_PAGE_SIZE		},
    166   { "_XOPEN_SHM",		SYSCONF,	_SC_XOPEN_SHM		},
    167 
    168   /* X/Open CAE Spec. Issue 5 Version 2 Configurable System Variables */
    169   { "FILESIZEBITS",		PATHCONF,	_PC_FILESIZEBITS	},
    170 
    171   /* POSIX.1-2001 XSI Option Group Configurable System Variables */
    172   { "ATEXIT_MAX",		SYSCONF,	_SC_ATEXIT_MAX		},
    173 
    174   /* POSIX.1-2001 TSF Configurable System Variables */
    175   { "GETGR_R_SIZE_MAX",		SYSCONF,	_SC_GETGR_R_SIZE_MAX	},
    176   { "GETPW_R_SIZE_MAX",		SYSCONF,	_SC_GETPW_R_SIZE_MAX	},
    177 
    178   /* Extensions found in Solaris and Linux. */
    179   { "SC_PHYS_PAGES",		SYSCONF,	_SC_PHYS_PAGES		},
    180   { "SC_AVPHYS_PAGES",		SYSCONF,	_SC_AVPHYS_PAGES	},
    181 
    182 #ifdef _NETBSD_SOURCE
    183   /* Commonly provided extensions */
    184   { "NPROCESSORS_CONF",		SYSCONF,	_SC_NPROCESSORS_CONF	},
    185   { "NPROCESSORS_ONLN",		SYSCONF,	_SC_NPROCESSORS_ONLN	},
    186 #endif	/* _NETBSD_SOURCE */
    187 
    188   { NULL, CONSTANT, 0L }
    189 };
    190 
    191 static int a_flag = 0;		/* list all variables */
    192 
    193 int
    194 main(int argc, char **argv)
    195 {
    196 	int ch;
    197 	const struct conf_variable *cp;
    198 	const char *varname, *pathname, *vn;
    199 	int found;
    200 
    201 	setprogname(argv[0]);
    202 	(void)setlocale(LC_ALL, "");
    203 
    204 	while ((ch = getopt(argc, argv, "a")) != -1) {
    205 		switch (ch) {
    206 		case 'a':
    207 			a_flag = 1;
    208 			break;
    209 		case '?':
    210 		default:
    211 			usage();
    212 		}
    213 	}
    214 	argc -= optind;
    215 	argv += optind;
    216 
    217 	if (!a_flag) {
    218 		if (argc == 0)
    219 			usage();
    220 		varname = argv[0];
    221 		argc--;
    222 		argv++;
    223 	} else
    224 		varname = NULL;
    225 
    226 	if (argc > 1)
    227 		usage();
    228 	pathname = argv[0];	/* may be NULL */
    229 
    230 	found = 0;
    231 	vn = varname;
    232 again:
    233 	for (cp = conf_table; cp->name != NULL; cp++) {
    234 		if (a_flag || strcmp(vn, cp->name) == 0) {
    235 			if ((cp->type == PATHCONF) == (pathname != NULL)) {
    236 				printvar(cp, pathname);
    237 				found = 1;
    238 			} else if (!a_flag)
    239 				errx(EXIT_FAILURE,
    240 				    "%s: invalid variable type", cp->name);
    241 		}
    242 	}
    243 
    244 	if (!a_flag && !found) {
    245 		if (*vn++ == '_')
    246 			goto again;
    247 		errx(EXIT_FAILURE, "%s: unknown variable", varname);
    248 	}
    249 
    250 	(void)fflush(stdout);
    251 	return ferror(stdout) ? EXIT_FAILURE : EXIT_SUCCESS;
    252 }
    253 
    254 static void
    255 print_longvar(const char *name, long value)
    256 {
    257 	if (a_flag)
    258 		(void)printf("%s = %ld\n", name, value);
    259 	else
    260 		(void)printf("%ld\n", value);
    261 }
    262 
    263 static void
    264 print_strvar(const char *name, const char *sval)
    265 {
    266 	if (a_flag)
    267 		(void)printf("%s = %s\n", name, sval);
    268 	else
    269 		(void)printf("%s\n", sval);
    270 }
    271 
    272 static void
    273 printvar(const struct conf_variable *cp, const char *pathname)
    274 {
    275 	size_t slen;
    276 	char *sval;
    277 	long val;
    278 
    279 	switch (cp->type) {
    280 	case CONSTANT:
    281 		print_longvar(cp->name, cp->value);
    282 		break;
    283 
    284 	case CONFSTR:
    285 		errno = 0;
    286 		slen = confstr((int)cp->value, NULL, 0);
    287 		if (slen == 0) {
    288 			if (errno != 0)
    289 
    290 out:			 	err(EXIT_FAILURE, "confstr(%ld)", cp->value);
    291 			else
    292 				print_strvar(cp->name, "undefined");
    293 		}
    294 
    295 		if ((sval = malloc(slen)) == NULL)
    296 			err(EXIT_FAILURE, "Can't allocate %zu bytes", slen);
    297 
    298 		errno = 0;
    299 		if (confstr((int)cp->value, sval, slen) == 0) {
    300 			if (errno != 0)
    301 				goto out;
    302 			else
    303 				print_strvar(cp->name, "undefined");
    304 		} else
    305 			print_strvar(cp->name, sval);
    306 
    307 		free(sval);
    308 		break;
    309 
    310 	case SYSCONF:
    311 		errno = 0;
    312 		if ((val = sysconf((int)cp->value)) == -1) {
    313 			if (errno != 0)
    314 				err(EXIT_FAILURE, "sysconf(%ld)", cp->value);
    315 			print_strvar(cp->name, "undefined");
    316 		} else
    317 			print_longvar(cp->name, val);
    318 		break;
    319 
    320 	case PATHCONF:
    321 		errno = 0;
    322 		if ((val = pathconf(pathname, (int)cp->value)) == -1) {
    323 			if (errno != 0) {
    324 				if (a_flag && errno == EINVAL) {
    325 					/* Just skip invalid variables */
    326 					return;
    327 				}
    328 				err(EXIT_FAILURE, "pathconf(%s, %ld)",
    329 				    pathname, cp->value);
    330 				/* NOTREACHED */
    331 			}
    332 
    333 			print_strvar(cp->name, "undefined");
    334 		} else
    335 			print_longvar(cp->name, val);
    336 		break;
    337 	}
    338 }
    339 
    340 
    341 static void
    342 usage(void)
    343 {
    344 	const char *p = getprogname();
    345 	(void)fprintf(stderr, "Usage: %s system_var\n\t%s -a\n"
    346 	    "\t%s path_var pathname\n\t%s -a pathname\n", p, p, p, p);
    347 	exit(EXIT_FAILURE);
    348 }
    349