Mercurial > hg > octave-kai > gnulib-hg
annotate lib/getusershell.c @ 790:8f31f8f77f98
remove trailing blanks
| author | Jim Meyering <jim@meyering.net> |
|---|---|
| date | Sun, 24 Nov 1996 03:04:12 +0000 |
| parents | b63f146fd963 |
| children | 2ca05983490f |
| 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 | |
|
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15 along with this program; if not, write to the Free Software Foundation, |
|
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update FSF address in copyright
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16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 9 | 17 |
| 18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> */ | |
| 19 | |
| 125 | 20 #ifdef HAVE_CONFIG_H |
| 653 | 21 # include <config.h> |
| 125 | 22 #endif |
| 23 | |
| 9 | 24 #ifndef SHELLS_FILE |
| 25 /* File containing a list of nonrestricted shells, one per line. */ | |
| 653 | 26 # define SHELLS_FILE "/etc/shells" |
| 9 | 27 #endif |
| 28 | |
| 29 #include <stdio.h> | |
| 30 #include <ctype.h> | |
| 31 | |
| 32 #ifdef STDC_HEADERS | |
| 653 | 33 # include <stdlib.h> |
| 9 | 34 #else |
| 35 char *malloc (); | |
| 36 char *realloc (); | |
| 37 #endif | |
| 38 | |
| 167 | 39 char *xstrdup (); |
| 40 | |
| 9 | 41 static int readname (); |
| 42 | |
| 43 /* List of shells to use if the shells file is missing. */ | |
|
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44 static char const* const default_shells[] = |
| 9 | 45 { |
| 46 "/bin/sh", "/bin/csh", "/usr/bin/sh", "/usr/bin/csh", NULL | |
| 47 }; | |
| 48 | |
| 49 /* Index of the next shell in `default_shells' to return. | |
| 50 0 means we are not using `default_shells'. */ | |
| 51 static int default_index = 0; | |
| 52 | |
| 53 /* Input stream from the shells file. */ | |
| 54 static FILE *shellstream = NULL; | |
| 55 | |
| 56 /* Line of input from the shells file. */ | |
| 57 static char *line = NULL; | |
| 58 | |
| 59 /* Number of bytes allocated for `line'. */ | |
| 60 static int line_size = 0; | |
| 61 | |
| 62 /* Return an entry from the shells file, ignoring comment lines. | |
| 167 | 63 If the file doesn't exist, use the list in DEFAULT_SHELLS (above). |
| 64 In any case, the returned string is in memory allocated through malloc. | |
| 9 | 65 Return NULL if there are no more entries. */ |
| 66 | |
| 67 char * | |
| 68 getusershell () | |
| 69 { | |
| 70 if (default_index > 0) | |
| 71 { | |
| 72 if (default_shells[default_index]) | |
| 73 /* Not at the end of the list yet. */ | |
| 167 | 74 return xstrdup (default_shells[default_index++]); |
| 9 | 75 return NULL; |
| 76 } | |
| 77 | |
| 78 if (shellstream == NULL) | |
| 79 { | |
| 80 shellstream = fopen (SHELLS_FILE, "r"); | |
| 81 if (shellstream == NULL) | |
| 82 { | |
| 83 /* No shells file. Use the default list. */ | |
| 84 default_index = 1; | |
| 167 | 85 return xstrdup (default_shells[0]); |
| 9 | 86 } |
| 87 } | |
| 88 | |
| 89 while (readname (&line, &line_size, shellstream)) | |
| 90 { | |
| 91 if (*line != '#') | |
| 92 return line; | |
| 93 } | |
| 94 return NULL; /* End of file. */ | |
| 95 } | |
| 96 | |
| 97 /* Rewind the shells file. */ | |
| 98 | |
| 99 void | |
| 100 setusershell () | |
| 101 { | |
| 102 default_index = 0; | |
| 103 if (shellstream == NULL) | |
| 104 shellstream = fopen (SHELLS_FILE, "r"); | |
| 105 else | |
| 106 fseek (shellstream, 0L, 0); | |
| 107 } | |
| 108 | |
| 109 /* Close the shells file. */ | |
| 110 | |
| 111 void | |
| 112 endusershell () | |
| 113 { | |
| 114 if (shellstream) | |
| 115 { | |
| 116 fclose (shellstream); | |
| 117 shellstream = NULL; | |
| 118 } | |
| 119 } | |
| 120 | |
| 121 /* Allocate N bytes of memory dynamically, with error checking. */ | |
| 122 | |
| 123 static char * | |
| 124 xmalloc (n) | |
| 125 unsigned n; | |
| 126 { | |
| 127 char *p; | |
| 128 | |
| 129 p = malloc (n); | |
| 130 if (p == 0) | |
| 131 { | |
| 132 fprintf (stderr, "virtual memory exhausted\n"); | |
| 133 exit (1); | |
| 134 } | |
| 135 return p; | |
| 136 } | |
| 137 | |
| 138 /* Reallocate space P to size N, with error checking. */ | |
| 139 | |
| 140 static char * | |
| 141 xrealloc (p, n) | |
| 142 char *p; | |
| 143 unsigned n; | |
| 144 { | |
| 145 p = realloc (p, n); | |
| 146 if (p == 0) | |
| 147 { | |
| 148 fprintf (stderr, "virtual memory exhausted\n"); | |
| 149 exit (1); | |
| 150 } | |
| 151 return p; | |
| 152 } | |
| 153 | |
| 154 /* Read a line from STREAM, removing any newline at the end. | |
| 155 Place the result in *NAME, which is malloc'd | |
| 156 and/or realloc'd as necessary and can start out NULL, | |
| 157 and whose size is passed and returned in *SIZE. | |
| 158 | |
| 159 Return the number of characters placed in *NAME | |
| 160 if some nonempty sequence was found, otherwise 0. */ | |
| 161 | |
| 162 static int | |
| 163 readname (name, size, stream) | |
| 164 char **name; | |
| 165 int *size; | |
| 166 FILE *stream; | |
| 167 { | |
| 168 int c; | |
| 169 int name_index = 0; | |
| 170 | |
| 171 if (*name == NULL) | |
| 172 { | |
| 173 *size = 10; | |
| 174 *name = (char *) xmalloc (*size); | |
| 175 } | |
| 176 | |
| 177 /* Skip blank space. */ | |
| 178 while ((c = getc (stream)) != EOF && isspace (c)) | |
| 179 /* Do nothing. */ ; | |
| 790 | 180 |
| 9 | 181 while (c != EOF && !isspace (c)) |
| 182 { | |
| 183 (*name)[name_index++] = c; | |
| 184 while (name_index >= *size) | |
| 185 { | |
| 186 *size *= 2; | |
| 187 *name = (char *) xrealloc (*name, *size); | |
| 188 } | |
| 189 c = getc (stream); | |
| 190 } | |
| 191 (*name)[name_index] = '\0'; | |
| 192 return name_index; | |
| 193 } | |
| 194 | |
| 195 #ifdef TEST | |
| 196 main () | |
| 197 { | |
| 198 char *s; | |
| 199 | |
| 200 while (s = getusershell ()) | |
| 201 puts (s); | |
| 202 exit (0); | |
| 203 } | |
| 204 #endif |