Mercurial > hg > octave-kai > gnulib-hg
annotate lib/getusershell.c @ 125:539738c0b6c2
merge with 1.8.1d
| author | Jim Meyering <jim@meyering.net> |
|---|---|
| date | Tue, 12 Oct 1993 14:49:15 +0000 (1993-10-12) |
| parents | 01c6d40adf9d |
| children | 585326d9a995 |
| rev | line source |
|---|---|
| 9 | 1 /* getusershell.c -- Return names of valid user shells. |
| 2 Copyright (C) 1991 Free Software Foundation, Inc. | |
| 3 | |
| 4 This program is free software; you can redistribute it and/or modify | |
| 5 it under the terms of the GNU General Public License as published by | |
| 6 the Free Software Foundation; either version 2, or (at your option) | |
| 7 any later version. | |
| 8 | |
| 9 This program is distributed in the hope that it will be useful, | |
| 10 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 12 GNU General Public License for more details. | |
| 13 | |
| 14 You should have received a copy of the GNU General Public License | |
| 15 along with this program; if not, write to the Free Software | |
| 16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
| 17 | |
| 18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> */ | |
| 19 | |
| 125 | 20 #ifdef HAVE_CONFIG_H |
| 21 #if defined (CONFIG_BROKETS) | |
| 22 /* We use <config.h> instead of "config.h" so that a compilation | |
| 23 using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h | |
| 24 (which it would do because it found this file in $srcdir). */ | |
| 25 #include <config.h> | |
| 26 #else | |
| 27 #include "config.h" | |
| 28 #endif | |
| 29 #endif | |
| 30 | |
| 9 | 31 #ifndef SHELLS_FILE |
| 32 /* File containing a list of nonrestricted shells, one per line. */ | |
| 33 #define SHELLS_FILE "/etc/shells" | |
| 34 #endif | |
| 35 | |
| 36 #include <stdio.h> | |
| 37 #include <ctype.h> | |
| 38 | |
| 39 #ifdef STDC_HEADERS | |
| 40 #include <stdlib.h> | |
| 41 #else | |
| 42 char *malloc (); | |
| 43 char *realloc (); | |
| 44 #endif | |
| 45 | |
| 46 static int readname (); | |
| 47 | |
| 48 /* List of shells to use if the shells file is missing. */ | |
|
16
01c6d40adf9d
Make tables static and const when possible.
Jim Meyering <jim@meyering.net>
parents:
9
diff
changeset
|
49 static char const* const default_shells[] = |
| 9 | 50 { |
| 51 "/bin/sh", "/bin/csh", "/usr/bin/sh", "/usr/bin/csh", NULL | |
| 52 }; | |
| 53 | |
| 54 /* Index of the next shell in `default_shells' to return. | |
| 55 0 means we are not using `default_shells'. */ | |
| 56 static int default_index = 0; | |
| 57 | |
| 58 /* Input stream from the shells file. */ | |
| 59 static FILE *shellstream = NULL; | |
| 60 | |
| 61 /* Line of input from the shells file. */ | |
| 62 static char *line = NULL; | |
| 63 | |
| 64 /* Number of bytes allocated for `line'. */ | |
| 65 static int line_size = 0; | |
| 66 | |
| 67 /* Return an entry from the shells file, ignoring comment lines. | |
| 68 Return NULL if there are no more entries. */ | |
| 69 | |
| 70 char * | |
| 71 getusershell () | |
| 72 { | |
| 73 if (default_index > 0) | |
| 74 { | |
| 75 if (default_shells[default_index]) | |
| 76 /* Not at the end of the list yet. */ | |
| 77 return default_shells[default_index++]; | |
| 78 return NULL; | |
| 79 } | |
| 80 | |
| 81 if (shellstream == NULL) | |
| 82 { | |
| 83 shellstream = fopen (SHELLS_FILE, "r"); | |
| 84 if (shellstream == NULL) | |
| 85 { | |
| 86 /* No shells file. Use the default list. */ | |
| 87 default_index = 1; | |
| 88 return default_shells[0]; | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 while (readname (&line, &line_size, shellstream)) | |
| 93 { | |
| 94 if (*line != '#') | |
| 95 return line; | |
| 96 } | |
| 97 return NULL; /* End of file. */ | |
| 98 } | |
| 99 | |
| 100 /* Rewind the shells file. */ | |
| 101 | |
| 102 void | |
| 103 setusershell () | |
| 104 { | |
| 105 default_index = 0; | |
| 106 if (shellstream == NULL) | |
| 107 shellstream = fopen (SHELLS_FILE, "r"); | |
| 108 else | |
| 109 fseek (shellstream, 0L, 0); | |
| 110 } | |
| 111 | |
| 112 /* Close the shells file. */ | |
| 113 | |
| 114 void | |
| 115 endusershell () | |
| 116 { | |
| 117 if (shellstream) | |
| 118 { | |
| 119 fclose (shellstream); | |
| 120 shellstream = NULL; | |
| 121 } | |
| 122 } | |
| 123 | |
| 124 /* Allocate N bytes of memory dynamically, with error checking. */ | |
| 125 | |
| 126 static char * | |
| 127 xmalloc (n) | |
| 128 unsigned n; | |
| 129 { | |
| 130 char *p; | |
| 131 | |
| 132 p = malloc (n); | |
| 133 if (p == 0) | |
| 134 { | |
| 135 fprintf (stderr, "virtual memory exhausted\n"); | |
| 136 exit (1); | |
| 137 } | |
| 138 return p; | |
| 139 } | |
| 140 | |
| 141 /* Reallocate space P to size N, with error checking. */ | |
| 142 | |
| 143 static char * | |
| 144 xrealloc (p, n) | |
| 145 char *p; | |
| 146 unsigned n; | |
| 147 { | |
| 148 p = realloc (p, n); | |
| 149 if (p == 0) | |
| 150 { | |
| 151 fprintf (stderr, "virtual memory exhausted\n"); | |
| 152 exit (1); | |
| 153 } | |
| 154 return p; | |
| 155 } | |
| 156 | |
| 157 /* Read a line from STREAM, removing any newline at the end. | |
| 158 Place the result in *NAME, which is malloc'd | |
| 159 and/or realloc'd as necessary and can start out NULL, | |
| 160 and whose size is passed and returned in *SIZE. | |
| 161 | |
| 162 Return the number of characters placed in *NAME | |
| 163 if some nonempty sequence was found, otherwise 0. */ | |
| 164 | |
| 165 static int | |
| 166 readname (name, size, stream) | |
| 167 char **name; | |
| 168 int *size; | |
| 169 FILE *stream; | |
| 170 { | |
| 171 int c; | |
| 172 int name_index = 0; | |
| 173 | |
| 174 if (*name == NULL) | |
| 175 { | |
| 176 *size = 10; | |
| 177 *name = (char *) xmalloc (*size); | |
| 178 } | |
| 179 | |
| 180 /* Skip blank space. */ | |
| 181 while ((c = getc (stream)) != EOF && isspace (c)) | |
| 182 /* Do nothing. */ ; | |
| 183 | |
| 184 while (c != EOF && !isspace (c)) | |
| 185 { | |
| 186 (*name)[name_index++] = c; | |
| 187 while (name_index >= *size) | |
| 188 { | |
| 189 *size *= 2; | |
| 190 *name = (char *) xrealloc (*name, *size); | |
| 191 } | |
| 192 c = getc (stream); | |
| 193 } | |
| 194 (*name)[name_index] = '\0'; | |
| 195 return name_index; | |
| 196 } | |
| 197 | |
| 198 #ifdef TEST | |
| 199 main () | |
| 200 { | |
| 201 char *s; | |
| 202 | |
| 203 while (s = getusershell ()) | |
| 204 puts (s); | |
| 205 exit (0); | |
| 206 } | |
| 207 #endif |