1 /* getusershell.c -- Return names of valid user shells.
3 Copyright (C) 1991, 1997, 2000, 2001, 2003, 2004 Free Software
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software Foundation,
18 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> */
28 /* File containing a list of nonrestricted shells, one per line. */
29 # define SHELLS_FILE "/etc/shells"
31 /* This is a horrible kludge. Isn't there a better way? */
32 # define SHELLS_FILE "/dev/env/DJDIR/etc/shells"
43 # include "unlocked-io.h"
46 #if defined (STDC_HEADERS) || (!defined (isascii) && !defined (HAVE_ISASCII))
47 # define IN_CTYPE_DOMAIN(c) 1
49 # define IN_CTYPE_DOMAIN(c) isascii(c)
52 #define ISSPACE(c) (IN_CTYPE_DOMAIN (c) && isspace (c))
54 static size_t readname (char **, size_t *, FILE *);
56 #if ! defined ADDITIONAL_DEFAULT_SHELLS && defined __MSDOS__
57 # define ADDITIONAL_DEFAULT_SHELLS \
58 "c:/dos/command.com", "c:/windows/command.com", "c:/command.com",
60 # define ADDITIONAL_DEFAULT_SHELLS /* empty */
63 /* List of shells to use if the shells file is missing. */
64 static char const* const default_shells[] =
66 ADDITIONAL_DEFAULT_SHELLS
67 "/bin/sh", "/bin/csh", "/usr/bin/sh", "/usr/bin/csh", NULL
70 /* Index of the next shell in `default_shells' to return.
71 0 means we are not using `default_shells'. */
72 static size_t default_index = 0;
74 /* Input stream from the shells file. */
75 static FILE *shellstream = NULL;
77 /* Line of input from the shells file. */
78 static char *line = NULL;
80 /* Number of bytes allocated for `line'. */
81 static size_t line_size = 0;
83 /* Return an entry from the shells file, ignoring comment lines.
84 If the file doesn't exist, use the list in DEFAULT_SHELLS (above).
85 In any case, the returned string is in memory allocated through malloc.
86 Return NULL if there are no more entries. */
91 if (default_index > 0)
93 if (default_shells[default_index])
94 /* Not at the end of the list yet. */
95 return xstrdup (default_shells[default_index++]);
99 if (shellstream == NULL)
101 shellstream = fopen (SHELLS_FILE, "r");
102 if (shellstream == NULL)
104 /* No shells file. Use the default list. */
106 return xstrdup (default_shells[0]);
110 while (readname (&line, &line_size, shellstream))
115 return NULL; /* End of file. */
118 /* Rewind the shells file. */
125 rewind (shellstream);
128 /* Close the shells file. */
135 fclose (shellstream);
140 /* Read a line from STREAM, removing any newline at the end.
141 Place the result in *NAME, which is malloc'd
142 and/or realloc'd as necessary and can start out NULL,
143 and whose size is passed and returned in *SIZE.
145 Return the number of bytes placed in *NAME
146 if some nonempty sequence was found, otherwise 0. */
149 readname (char **name, size_t *size, FILE *stream)
152 size_t name_index = 0;
154 /* Skip blank space. */
155 while ((c = getc (stream)) != EOF && ISSPACE (c))
160 if (*size <= name_index)
161 *name = x2nrealloc (*name, size, sizeof **name);
162 if (c == EOF || ISSPACE (c))
164 (*name)[name_index++] = c;
167 (*name)[name_index] = '\0';
177 while (s = getusershell ())