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getusershell.c revision 1.10 
      1 /*	$NetBSD: getusershell.c,v 1.10 1998/07/27 09:47:45 mycroft 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 1.10 1998/07/27 09:47:45 mycroft 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 	ret = (__aconst char *)*curshell;
     82 	if (ret != NULL)
     83 		curshell++;
     84 	return (ret);
     85 }
     86 
     87 void
     88 endusershell()
     89 {
     90 
     91 	if (shells != NULL)
     92 		free(shells);
     93 	shells = NULL;
     94 	if (strings != NULL)
     95 		free(strings);
     96 	strings = NULL;
     97 	curshell = NULL;
     98 }
     99 
    100 void
    101 setusershell()
    102 {
    103 
    104 	curshell = initshells();
    105 }
    106 
    107 static const char *const *
    108 initshells()
    109 {
    110 	const char **sp;
    111 	char *cp;
    112 	FILE *fp;
    113 	struct stat statb;
    114 
    115 	if (shells != NULL)
    116 		free(shells);
    117 	shells = NULL;
    118 	if (strings != NULL)
    119 		free(strings);
    120 	strings = NULL;
    121 	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
    122 		return (okshells);
    123 	if (fstat(fileno(fp), &statb) == -1) {
    124 		(void)fclose(fp);
    125 		return (okshells);
    126 	}
    127 	if ((cp = malloc((u_int)statb.st_size)) == NULL) {
    128 		(void)fclose(fp);
    129 		return (okshells);
    130 	}
    131 	sp = calloc((unsigned)statb.st_size / 3, sizeof (char *));
    132 	if (sp == NULL) {
    133 		(void)fclose(fp);
    134 		free(cp);
    135 		strings = NULL;
    136 		return (okshells);
    137 	}
    138 	shells = sp;
    139 	strings = cp;
    140 	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
    141 		while (*cp != '#' && *cp != '/' && *cp != '\0')
    142 			cp++;
    143 		if (*cp == '#' || *cp == '\0')
    144 			continue;
    145 		*sp++ = cp;
    146 		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
    147 			cp++;
    148 		*cp++ = '\0';
    149 	}
    150 	*sp = NULL;
    151 	(void)fclose(fp);
    152 	return (shells);
    153 }
    154