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getusershell.c revision 1.1.1.2 
      1 /*
      2  * Copyright (c) 1985, 1993
      3  *	The Regents of the University of California.  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[] = "@(#)getusershell.c	8.1 (Berkeley) 6/4/93";
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 #include <sys/param.h>
     39 #include <sys/file.h>
     40 #include <sys/stat.h>
     41 #include <stdio.h>
     42 #include <ctype.h>
     43 #include <stdlib.h>
     44 #include <unistd.h>
     45 #include <paths.h>
     46 
     47 /*
     48  * Local shells should NOT be added here.  They should be added in
     49  * /etc/shells.
     50  */
     51 
     52 static char *okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
     53 static char **curshell, **shells, *strings;
     54 static char **initshells __P((void));
     55 
     56 /*
     57  * Get a list of shells from _PATH_SHELLS, if it exists.
     58  */
     59 char *
     60 getusershell()
     61 {
     62 	char *ret;
     63 
     64 	if (curshell == NULL)
     65 		curshell = initshells();
     66 	ret = *curshell;
     67 	if (ret != NULL)
     68 		curshell++;
     69 	return (ret);
     70 }
     71 
     72 void
     73 endusershell()
     74 {
     75 
     76 	if (shells != NULL)
     77 		free(shells);
     78 	shells = NULL;
     79 	if (strings != NULL)
     80 		free(strings);
     81 	strings = NULL;
     82 	curshell = NULL;
     83 }
     84 
     85 void
     86 setusershell()
     87 {
     88 
     89 	curshell = initshells();
     90 }
     91 
     92 static char **
     93 initshells()
     94 {
     95 	register char **sp, *cp;
     96 	register FILE *fp;
     97 	struct stat statb;
     98 
     99 	if (shells != NULL)
    100 		free(shells);
    101 	shells = NULL;
    102 	if (strings != NULL)
    103 		free(strings);
    104 	strings = NULL;
    105 	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
    106 		return (okshells);
    107 	if (fstat(fileno(fp), &statb) == -1) {
    108 		(void)fclose(fp);
    109 		return (okshells);
    110 	}
    111 	if ((strings = malloc((u_int)statb.st_size)) == NULL) {
    112 		(void)fclose(fp);
    113 		return (okshells);
    114 	}
    115 	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
    116 	if (shells == NULL) {
    117 		(void)fclose(fp);
    118 		free(strings);
    119 		strings = NULL;
    120 		return (okshells);
    121 	}
    122 	sp = shells;
    123 	cp = strings;
    124 	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
    125 		while (*cp != '#' && *cp != '/' && *cp != '\0')
    126 			cp++;
    127 		if (*cp == '#' || *cp == '\0')
    128 			continue;
    129 		*sp++ = cp;
    130 		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
    131 			cp++;
    132 		*cp++ = '\0';
    133 	}
    134 	*sp = NULL;
    135 	(void)fclose(fp);
    136 	return (shells);
    137 }
    138