gen/getusershell.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Copyright (c) 1985, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the above copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. All advertising materials mentioning features or use of this software
  36  *    must display the following acknowledgement:
  37  *      This product includes software developed by the University of
  38  *      California, Berkeley and its contributors.
  39  * 4. Neither the name of the University nor the names of its contributors
  40  *    may be used to endorse or promote products derived from this software
  41  *    without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  */
  55
  56
  57 #include <sys/param.h>
  58 #include <sys/file.h>
  59 #include <sys/stat.h>
  60 #include <stdio.h>
  61 #include <ctype.h>
  62 #include <stdlib.h>
  63 #include <unistd.h>
  64 #include <paths.h>
  65
  66 /*
  67  * Local shells should NOT be added here.  They should be added in
  68  * /etc/shells.
  69  */
  70
  71 static char *okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
  72 static char **curshell, **shells, *strings;
  73 static char **initshells(void);
  74
  75 /*
  76  * Get a list of shells from _PATH_SHELLS, if it exists.
  77  */
  78 char *
  79 getusershell()
  80 {
  81         char *ret;
  82
  83         if (curshell == NULL)
  84                 curshell = initshells();
  85         ret = *curshell;
  86         if (ret != NULL)
  87                 curshell++;
  88         return (ret);
  89 }
  90
  91 void
  92 endusershell()
  93 {
  94
  95         if (shells != NULL)
  96                 free(shells);
  97         shells = NULL;
  98         if (strings != NULL)
  99                 free(strings);
 100         strings = NULL;
 101         curshell = NULL;
 102 }
 103
 104 void
 105 setusershell()
 106 {
 107
 108         curshell = initshells();
 109 }
 110
 111 static char **
 112 initshells()
 113 {
 114         register char **sp, *cp;
 115         register FILE *fp;
 116         struct stat statb;
 117
 118         if (shells != NULL)
 119                 free(shells);
 120         shells = NULL;
 121         if (strings != NULL)
 122                 free(strings);
 123         strings = NULL;
 124         if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
 125                 return (okshells);
 126         if (fstat(fileno(fp), &statb) == -1) {
 127                 (void)fclose(fp);
 128                 return (okshells);
 129         }
 130         if ((strings = malloc((u_int)statb.st_size)) == NULL) {
 131                 (void)fclose(fp);
 132                 return (okshells);
 133         }
 134         shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
 135         if (shells == NULL) {
 136                 (void)fclose(fp);
 137                 free(strings);
 138                 strings = NULL;
 139                 return (okshells);
 140         }
 141         sp = shells;
 142         cp = strings;
 143         while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
 144                 while (*cp != '#' && *cp != '/' && *cp != '\0')
 145                         cp++;
 146                 if (*cp == '#' || *cp == '\0')
 147                         continue;
 148                 *sp++ = cp;
 149                 while (!isspace(*cp) && *cp != '#' && *cp != '\0')
 150                         cp++;
 151                 *cp++ = '\0';
 152         }
 153         *sp = NULL;
 154         (void)fclose(fp);
 155         return (shells);
 156 }