misc/getttyent.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)getttyent.c 8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33
  34 #include <ttyent.h>
  35 #include <stdio.h>
  36 #include <ctype.h>
  37 #include <string.h>
  38
  39 #ifdef USE_IN_LIBIO
  40 # define flockfile(s) _IO_flockfile (s)
  41 # define funlockfile(s) _IO_funlockfile (s)
  42 #endif
  43
  44 static char zapchar;
  45 static FILE *tf;
  46
  47 struct ttyent *
  48 getttynam(tty)
  49         const char *tty;
  50 {
  51         register struct ttyent *t;
  52
  53         setttyent();
  54         while ((t = getttyent()))
  55                 if (!strcmp(tty, t->ty_name))
  56                         break;
  57         endttyent();
  58         return (t);
  59 }
  60
  61 static char *skip __P((char *)) internal_function;
  62 static char *value __P((char *)) internal_function;
  63
  64 struct ttyent *
  65 getttyent()
  66 {
  67         static struct ttyent tty;
  68         register int c;
  69         register char *p;
  70 #define MAXLINELENGTH   100
  71         static char line[MAXLINELENGTH];
  72
  73         if (!tf && !setttyent())
  74                 return (NULL);
  75         flockfile (tf);
  76         for (;;) {
  77                 if (!fgets_unlocked(p = line, sizeof(line), tf)) {
  78                         funlockfile (tf);
  79                         return (NULL);
  80                 }
  81                 /* skip lines that are too big */
  82                 if (!index(p, '\n')) {
  83                         while ((c = getc_unlocked(tf)) != '\n' && c != EOF)
  84                                 ;
  85                         continue;
  86                 }
  87                 while (isspace(*p))
  88                         ++p;
  89                 if (*p && *p != '#')
  90                         break;
  91         }
  92
  93         zapchar = 0;
  94         tty.ty_name = p;
  95         p = skip(p);
  96         if (!*(tty.ty_getty = p))
  97                 tty.ty_getty = tty.ty_type = NULL;
  98         else {
  99                 p = skip(p);
 100                 if (!*(tty.ty_type = p))
 101                         tty.ty_type = NULL;
 102                 else
 103                         p = skip(p);
 104         }
 105         tty.ty_status = 0;
 106         tty.ty_window = NULL;
 107
 108 #define scmp(e) !strncmp(p, e, sizeof(e) - 1) && isspace(p[sizeof(e) - 1])
 109 #define vcmp(e) !strncmp(p, e, sizeof(e) - 1) && p[sizeof(e) - 1] == '='
 110         for (; *p; p = skip(p)) {
 111                 if (scmp(_TTYS_OFF))
 112                         tty.ty_status &= ~TTY_ON;
 113                 else if (scmp(_TTYS_ON))
 114                         tty.ty_status |= TTY_ON;
 115                 else if (scmp(_TTYS_SECURE))
 116                         tty.ty_status |= TTY_SECURE;
 117                 else if (vcmp(_TTYS_WINDOW))
 118                         tty.ty_window = value(p);
 119                 else
 120                         break;
 121         }
 122         /* We can release the lock only here since `zapchar' is global.  */
 123         funlockfile(tf);
 124
 125         if (zapchar == '#' || *p == '#')
 126                 while ((c = *++p) == ' ' || c == '\t')
 127                         ;
 128         tty.ty_comment = p;
 129         if (*p == 0)
 130                 tty.ty_comment = 0;
 131         if ((p = index(p, '\n')))
 132                 *p = '\0';
 133         return (&tty);
 134 }
 135
 136 #define QUOTED  1
 137
 138 /*
 139  * Skip over the current field, removing quotes, and return a pointer to
 140  * the next field.
 141  */
 142 static char *
 143 internal_function
 144 skip(p)
 145         register char *p;
 146 {
 147         register char *t;
 148         register int c, q;
 149
 150         for (q = 0, t = p; (c = *p) != '\0'; p++) {
 151                 if (c == '"') {
 152                         q ^= QUOTED;    /* obscure, but nice */
 153                         continue;
 154                 }
 155                 if (q == QUOTED && *p == '\\' && *(p+1) == '"')
 156                         p++;
 157                 *t++ = *p;
 158                 if (q == QUOTED)
 159                         continue;
 160                 if (c == '#') {
 161                         zapchar = c;
 162                         *p = 0;
 163                         break;
 164                 }
 165                 if (c == '\t' || c == ' ' || c == '\n') {
 166                         zapchar = c;
 167                         *p++ = 0;
 168                         while ((c = *p) == '\t' || c == ' ' || c == '\n')
 169                                 p++;
 170                         break;
 171                 }
 172         }
 173         *--t = '\0';
 174         return (p);
 175 }
 176
 177 static char *
 178 internal_function
 179 value(p)
 180         register char *p;
 181 {
 182
 183         return ((p = index(p, '=')) ? ++p : NULL);
 184 }
 185
 186 int
 187 setttyent()
 188 {
 189
 190         if (tf) {
 191                 (void)rewind(tf);
 192                 return (1);
 193         } else if ((tf = fopen(_PATH_TTYS, "r")))
 194                 return (1);
 195         return (0);
 196 }
 197
 198 int
 199 endttyent()
 200 {
 201         int rval;
 202
 203         if (tf) {
 204                 rval = !(fclose(tf) == EOF);
 205                 tf = NULL;
 206                 return (rval);
 207         }
 208         return (1);
 209 }