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getusershell.c revision 1.11 
      1 /*	$NetBSD: getusershell.c,v 1.11 1998/11/13 10:26:19 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1985, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)getusershell.c	8.1 (Berkeley) 6/4/93";
     40 #else
     41 __RCSID("$NetBSD: getusershell.c,v 1.11 1998/11/13 10:26:19 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/param.h>
     47 #include <sys/file.h>
     48 #include <sys/stat.h>
     49 #include <stdio.h>
     50 #include <ctype.h>
     51 #include <stdlib.h>
     52 #include <unistd.h>
     53 #include <paths.h>
     54 
     55 #ifdef __weak_alias
     56 __weak_alias(endusershell,_endusershell);
     57 __weak_alias(getusershell,_getusershell);
     58 __weak_alias(setusershell,_setusershell);
     59 #endif
     60 
     61 /*
     62  * Local shells should NOT be added here.  They should be added in
     63  * /etc/shells.
     64  */
     65 
     66 static const char *const okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
     67 static const char *const *curshell, **shells;
     68 static char *strings;
     69 static const char *const *initshells __P((void));
     70 
     71 /*
     72  * Get a list of shells from _PATH_SHELLS, if it exists.
     73  */
     74 __aconst char *
     75 getusershell()
     76 {
     77 	__aconst char *ret;
     78 
     79 	if (curshell == NULL)
     80 		curshell = initshells();
     81 	/* LINTED (auditing puproses only */
     82 	ret = (__aconst char *)*curshell;
     83 	if (ret != NULL)
     84 		curshell++;
     85 	return (ret);
     86 }
     87 
     88 void
     89 endusershell()
     90 {
     91 
     92 	if (shells != NULL)
     93 		free(shells);
     94 	shells = NULL;
     95 	if (strings != NULL)
     96 		free(strings);
     97 	strings = NULL;
     98 	curshell = NULL;
     99 }
    100 
    101 void
    102 setusershell()
    103 {
    104 
    105 	curshell = initshells();
    106 }
    107 
    108 static const char *const *
    109 initshells()
    110 {
    111 	const char **sp;
    112 	char *cp;
    113 	FILE *fp;
    114 	struct stat statb;
    115 
    116 	if (shells != NULL)
    117 		free(shells);
    118 	shells = NULL;
    119 	if (strings != NULL)
    120 		free(strings);
    121 	strings = NULL;
    122 	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
    123 		return (okshells);
    124 	if (fstat(fileno(fp), &statb) == -1) {
    125 		(void)fclose(fp);
    126 		return (okshells);
    127 	}
    128 	if ((cp = malloc((u_int)statb.st_size)) == NULL) {
    129 		(void)fclose(fp);
    130 		return (okshells);
    131 	}
    132 	sp = calloc((unsigned)statb.st_size / 3, sizeof (char *));
    133 	if (sp == NULL) {
    134 		(void)fclose(fp);
    135 		free(cp);
    136 		strings = NULL;
    137 		return (okshells);
    138 	}
    139 	shells = sp;
    140 	strings = cp;
    141 	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
    142 		while (*cp != '#' && *cp != '/' && *cp != '\0')
    143 			cp++;
    144 		if (*cp == '#' || *cp == '\0')
    145 			continue;
    146 		*sp++ = cp;
    147 		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
    148 			cp++;
    149 		*cp++ = '\0';
    150 	}
    151 	*sp = NULL;
    152 	(void)fclose(fp);
    153 	return (shells);
    154 }
    155