Mercurial > hg > octave-kai > gnulib-hg
annotate lib/getusershell.c @ 16:01c6d40adf9d
Make tables static and const when possible.
getdate.c (getdate_yyerr, getdate_yylex): Declare these functions static.
| author | Jim Meyering <jim@meyering.net> |
|---|---|
| date | Thu, 12 Nov 1992 04:13:46 +0000 (1992-11-12) |
| parents | f8dce34b5ab0 |
| children | 21add36c3efa |
| 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 | |
| 20 #ifndef SHELLS_FILE | |
| 21 /* File containing a list of nonrestricted shells, one per line. */ | |
| 22 #define SHELLS_FILE "/etc/shells" | |
| 23 #endif | |
| 24 | |
| 25 #include <stdio.h> | |
| 26 #include <ctype.h> | |
| 27 | |
| 28 #ifdef STDC_HEADERS | |
| 29 #include <stdlib.h> | |
| 30 #else | |
| 31 char *malloc (); | |
| 32 char *realloc (); | |
| 33 #endif | |
| 34 | |
| 35 static int readname (); | |
| 36 | |
| 37 /* 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
|
38 static char const* const default_shells[] = |
| 9 | 39 { |
| 40 "/bin/sh", "/bin/csh", "/usr/bin/sh", "/usr/bin/csh", NULL | |
| 41 }; | |
| 42 | |
| 43 /* Index of the next shell in `default_shells' to return. | |
| 44 0 means we are not using `default_shells'. */ | |
| 45 static int default_index = 0; | |
| 46 | |
| 47 /* Input stream from the shells file. */ | |
| 48 static FILE *shellstream = NULL; | |
| 49 | |
| 50 /* Line of input from the shells file. */ | |
| 51 static char *line = NULL; | |
| 52 | |
| 53 /* Number of bytes allocated for `line'. */ | |
| 54 static int line_size = 0; | |
| 55 | |
| 56 /* Return an entry from the shells file, ignoring comment lines. | |
| 57 Return NULL if there are no more entries. */ | |
| 58 | |
| 59 char * | |
| 60 getusershell () | |
| 61 { | |
| 62 if (default_index > 0) | |
| 63 { | |
| 64 if (default_shells[default_index]) | |
| 65 /* Not at the end of the list yet. */ | |
| 66 return default_shells[default_index++]; | |
| 67 return NULL; | |
| 68 } | |
| 69 | |
| 70 if (shellstream == NULL) | |
| 71 { | |
| 72 shellstream = fopen (SHELLS_FILE, "r"); | |
| 73 if (shellstream == NULL) | |
| 74 { | |
| 75 /* No shells file. Use the default list. */ | |
| 76 default_index = 1; | |
| 77 return default_shells[0]; | |
| 78 } | |
| 79 } | |
| 80 | |
| 81 while (readname (&line, &line_size, shellstream)) | |
| 82 { | |
| 83 if (*line != '#') | |
| 84 return line; | |
| 85 } | |
| 86 return NULL; /* End of file. */ | |
| 87 } | |
| 88 | |
| 89 /* Rewind the shells file. */ | |
| 90 | |
| 91 void | |
| 92 setusershell () | |
| 93 { | |
| 94 default_index = 0; | |
| 95 if (shellstream == NULL) | |
| 96 shellstream = fopen (SHELLS_FILE, "r"); | |
| 97 else | |
| 98 fseek (shellstream, 0L, 0); | |
| 99 } | |
| 100 | |
| 101 /* Close the shells file. */ | |
| 102 | |
| 103 void | |
| 104 endusershell () | |
| 105 { | |
| 106 if (shellstream) | |
| 107 { | |
| 108 fclose (shellstream); | |
| 109 shellstream = NULL; | |
| 110 } | |
| 111 } | |
| 112 | |
| 113 /* Allocate N bytes of memory dynamically, with error checking. */ | |
| 114 | |
| 115 static char * | |
| 116 xmalloc (n) | |
| 117 unsigned n; | |
| 118 { | |
| 119 char *p; | |
| 120 | |
| 121 p = malloc (n); | |
| 122 if (p == 0) | |
| 123 { | |
| 124 fprintf (stderr, "virtual memory exhausted\n"); | |
| 125 exit (1); | |
| 126 } | |
| 127 return p; | |
| 128 } | |
| 129 | |
| 130 /* Reallocate space P to size N, with error checking. */ | |
| 131 | |
| 132 static char * | |
| 133 xrealloc (p, n) | |
| 134 char *p; | |
| 135 unsigned n; | |
| 136 { | |
| 137 p = realloc (p, n); | |
| 138 if (p == 0) | |
| 139 { | |
| 140 fprintf (stderr, "virtual memory exhausted\n"); | |
| 141 exit (1); | |
| 142 } | |
| 143 return p; | |
| 144 } | |
| 145 | |
| 146 /* Read a line from STREAM, removing any newline at the end. | |
| 147 Place the result in *NAME, which is malloc'd | |
| 148 and/or realloc'd as necessary and can start out NULL, | |
| 149 and whose size is passed and returned in *SIZE. | |
| 150 | |
| 151 Return the number of characters placed in *NAME | |
| 152 if some nonempty sequence was found, otherwise 0. */ | |
| 153 | |
| 154 static int | |
| 155 readname (name, size, stream) | |
| 156 char **name; | |
| 157 int *size; | |
| 158 FILE *stream; | |
| 159 { | |
| 160 int c; | |
| 161 int name_index = 0; | |
| 162 | |
| 163 if (*name == NULL) | |
| 164 { | |
| 165 *size = 10; | |
| 166 *name = (char *) xmalloc (*size); | |
| 167 } | |
| 168 | |
| 169 /* Skip blank space. */ | |
| 170 while ((c = getc (stream)) != EOF && isspace (c)) | |
| 171 /* Do nothing. */ ; | |
| 172 | |
| 173 while (c != EOF && !isspace (c)) | |
| 174 { | |
| 175 (*name)[name_index++] = c; | |
| 176 while (name_index >= *size) | |
| 177 { | |
| 178 *size *= 2; | |
| 179 *name = (char *) xrealloc (*name, *size); | |
| 180 } | |
| 181 c = getc (stream); | |
| 182 } | |
| 183 (*name)[name_index] = '\0'; | |
| 184 return name_index; | |
| 185 } | |
| 186 | |
| 187 #ifdef TEST | |
| 188 main () | |
| 189 { | |
| 190 char *s; | |
| 191 | |
| 192 while (s = getusershell ()) | |
| 193 puts (s); | |
| 194 exit (0); | |
| 195 } | |
| 196 #endif |