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getusershell.c revision 1.6 
      1 /*	$NetBSD: getusershell.c,v 1.6 1997/07/13 19:46:02 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 1.6 1997/07/13 19:46:02 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include <sys/param.h>
     46 #include <sys/file.h>
     47 #include <sys/stat.h>
     48 #include <stdio.h>
     49 #include <ctype.h>
     50 #include <stdlib.h>
     51 #include <unistd.h>
     52 #include <paths.h>
     53 
     54 /*
     55  * Local shells should NOT be added here.  They should be added in
     56  * /etc/shells.
     57  */
     58 
     59 static char *okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
     60 static char **curshell, **shells, *strings;
     61 static char **initshells __P((void));
     62 
     63 /*
     64  * Get a list of shells from _PATH_SHELLS, if it exists.
     65  */
     66 char *
     67 getusershell()
     68 {
     69 	char *ret;
     70 
     71 	if (curshell == NULL)
     72 		curshell = initshells();
     73 	ret = *curshell;
     74 	if (ret != NULL)
     75 		curshell++;
     76 	return (ret);
     77 }
     78 
     79 void
     80 endusershell()
     81 {
     82 
     83 	if (shells != NULL)
     84 		free(shells);
     85 	shells = NULL;
     86 	if (strings != NULL)
     87 		free(strings);
     88 	strings = NULL;
     89 	curshell = NULL;
     90 }
     91 
     92 void
     93 setusershell()
     94 {
     95 
     96 	curshell = initshells();
     97 }
     98 
     99 static char **
    100 initshells()
    101 {
    102 	register char **sp, *cp;
    103 	register FILE *fp;
    104 	struct stat statb;
    105 
    106 	if (shells != NULL)
    107 		free(shells);
    108 	shells = NULL;
    109 	if (strings != NULL)
    110 		free(strings);
    111 	strings = NULL;
    112 	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
    113 		return (okshells);
    114 	if (fstat(fileno(fp), &statb) == -1) {
    115 		(void)fclose(fp);
    116 		return (okshells);
    117 	}
    118 	if ((strings = malloc((u_int)statb.st_size)) == NULL) {
    119 		(void)fclose(fp);
    120 		return (okshells);
    121 	}
    122 	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
    123 	if (shells == NULL) {
    124 		(void)fclose(fp);
    125 		free(strings);
    126 		strings = NULL;
    127 		return (okshells);
    128 	}
    129 	sp = shells;
    130 	cp = strings;
    131 	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
    132 		while (*cp != '#' && *cp != '/' && *cp != '\0')
    133 			cp++;
    134 		if (*cp == '#' || *cp == '\0')
    135 			continue;
    136 		*sp++ = cp;
    137 		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
    138 			cp++;
    139 		*cp++ = '\0';
    140 	}
    141 	*sp = NULL;
    142 	(void)fclose(fp);
    143 	return (shells);
    144 }
    145