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getusershell.c revision 1.4.4.1 
      1 /*
      2  * Copyright (c) 1985 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 /*static char *sccsid = "from: @(#)getusershell.c	5.7 (Berkeley) 2/23/91";*/
     36 static char *rcsid = "$Id: getusershell.c,v 1.4.4.1 1995/05/02 19:34:50 jtc Exp $";
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 #include "namespace.h"
     40 #include <sys/param.h>
     41 #include <sys/file.h>
     42 #include <sys/stat.h>
     43 #include <ctype.h>
     44 #include <stdio.h>
     45 #include <stdlib.h>
     46 #include <unistd.h>
     47 
     48 #define SHELLS "/etc/shells"
     49 
     50 /*
     51  * Do not add local shells here.  They should be added in /etc/shells
     52  */
     53 static char *okshells[] =
     54     { "/bin/sh", "/bin/csh", 0 };
     55 
     56 static char **shells, *strings;
     57 static char **curshell = NULL;
     58 static char **initshells();
     59 
     60 /*
     61  * Get a list of shells from SHELLS, if it exists.
     62  */
     63 char *
     64 getusershell()
     65 {
     66 	char *ret;
     67 
     68 	if (curshell == NULL)
     69 		curshell = initshells();
     70 	ret = *curshell;
     71 	if (ret != NULL)
     72 		curshell++;
     73 	return (ret);
     74 }
     75 
     76 void
     77 endusershell()
     78 {
     79 
     80 	if (shells != NULL)
     81 		free((char *)shells);
     82 	shells = NULL;
     83 	if (strings != NULL)
     84 		free(strings);
     85 	strings = NULL;
     86 	curshell = NULL;
     87 }
     88 
     89 void
     90 setusershell()
     91 {
     92 
     93 	curshell = initshells();
     94 }
     95 
     96 static char **
     97 initshells()
     98 {
     99 	register char **sp, *cp;
    100 	register FILE *fp;
    101 	struct stat statb;
    102 
    103 	if (shells != NULL)
    104 		free((char *)shells);
    105 	shells = NULL;
    106 	if (strings != NULL)
    107 		free(strings);
    108 	strings = NULL;
    109 	if ((fp = fopen(SHELLS, "r")) == (FILE *)0)
    110 		return(okshells);
    111 	if (fstat(fileno(fp), &statb) == -1) {
    112 		(void)fclose(fp);
    113 		return(okshells);
    114 	}
    115 	if ((strings = malloc((unsigned)statb.st_size)) == NULL) {
    116 		(void)fclose(fp);
    117 		return(okshells);
    118 	}
    119 	shells = (char **)calloc((unsigned)statb.st_size / 3, sizeof (char *));
    120 	if (shells == NULL) {
    121 		(void)fclose(fp);
    122 		free(strings);
    123 		strings = NULL;
    124 		return(okshells);
    125 	}
    126 	sp = shells;
    127 	cp = strings;
    128 	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
    129 		while (*cp != '#' && *cp != '/' && *cp != '\0')
    130 			cp++;
    131 		if (*cp == '#' || *cp == '\0')
    132 			continue;
    133 		*sp++ = cp;
    134 		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
    135 			cp++;
    136 		*cp++ = '\0';
    137 	}
    138 	*sp = (char *)0;
    139 	(void)fclose(fp);
    140 	return (shells);
    141 }
    142