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 <stdio_ext.h>
  37 #include <ctype.h>
  38 #include <string.h>
  39
  40 #ifdef USE_IN_LIBIO
  41 # define flockfile(s) _IO_flockfile (s)
  42 # define funlockfile(s) _IO_funlockfile (s)
  43 #endif
  44
  45 static char zapchar;
  46 static FILE *tf;
  47
  48 struct ttyent *
  49 getttynam(tty)
  50         const char *tty;
  51 {
  52         register struct ttyent *t;
  53
  54         setttyent();
  55         while ((t = getttyent()))
  56                 if (!strcmp(tty, t->ty_name))
  57                         break;
  58         endttyent();
  59         return (t);
  60 }
  61
  62 static char *skip (char *) __THROW internal_function;
  63 static char *value (char *) __THROW internal_function;
  64
  65 struct ttyent *
  66 getttyent()
  67 {
  68         static struct ttyent tty;
  69         register int c;
  70         register char *p;
  71 #define MAXLINELENGTH   100
  72         static char line[MAXLINELENGTH];
  73
  74         if (!tf && !setttyent())
  75                 return (NULL);
  76         flockfile (tf);
  77         for (;;) {
  78                 if (!fgets_unlocked(p = line, sizeof(line), tf)) {
  79                         funlockfile (tf);
  80                         return (NULL);
  81                 }
  82                 /* skip lines that are too big */
  83                 if (!index(p, '\n')) {
  84                         while ((c = getc_unlocked(tf)) != '\n' && c != EOF)
  85                                 ;
  86                         continue;
  87                 }
  88                 while (isspace(*p))
  89                         ++p;
  90                 if (*p && *p != '#')
  91                         break;
  92         }
  93
  94         zapchar = 0;
  95         tty.ty_name = p;
  96         p = skip(p);
  97         if (!*(tty.ty_getty = p))
  98                 tty.ty_getty = tty.ty_type = NULL;
  99         else {
 100                 p = skip(p);
 101                 if (!*(tty.ty_type = p))
 102                         tty.ty_type = NULL;
 103                 else
 104                         p = skip(p);
 105         }
 106         tty.ty_status = 0;
 107         tty.ty_window = NULL;
 108
 109 #define scmp(e) !strncmp(p, e, sizeof(e) - 1) && isspace(p[sizeof(e) - 1])
 110 #define vcmp(e) !strncmp(p, e, sizeof(e) - 1) && p[sizeof(e) - 1] == '='
 111         for (; *p; p = skip(p)) {
 112                 if (scmp(_TTYS_OFF))
 113                         tty.ty_status &= ~TTY_ON;
 114                 else if (scmp(_TTYS_ON))
 115                         tty.ty_status |= TTY_ON;
 116                 else if (scmp(_TTYS_SECURE))
 117                         tty.ty_status |= TTY_SECURE;
 118                 else if (vcmp(_TTYS_WINDOW))
 119                         tty.ty_window = value(p);
 120                 else
 121                         break;
 122         }
 123         /* We can release the lock only here since `zapchar' is global.  */
 124         funlockfile(tf);
 125
 126         if (zapchar == '#' || *p == '#')
 127                 while ((c = *++p) == ' ' || c == '\t')
 128                         ;
 129         tty.ty_comment = p;
 130         if (*p == 0)
 131                 tty.ty_comment = 0;
 132         if ((p = index(p, '\n')))
 133                 *p = '\0';
 134         return (&tty);
 135 }
 136 libc_hidden_def (getttyent)
 137
 138 #define QUOTED  1
 139
 140 /*
 141  * Skip over the current field, removing quotes, and return a pointer to
 142  * the next field.
 143  */
 144 static char *
 145 internal_function
 146 skip(p)
 147         register char *p;
 148 {
 149         register char *t;
 150         register int c, q;
 151
 152         for (q = 0, t = p; (c = *p) != '\0'; p++) {
 153                 if (c == '"') {
 154                         q ^= QUOTED;    /* obscure, but nice */
 155                         continue;
 156                 }
 157                 if (q == QUOTED && *p == '\\' && *(p+1) == '"')
 158                         p++;
 159                 *t++ = *p;
 160                 if (q == QUOTED)
 161                         continue;
 162                 if (c == '#') {
 163                         zapchar = c;
 164                         *p = 0;
 165                         break;
 166                 }
 167                 if (c == '\t' || c == ' ' || c == '\n') {
 168                         zapchar = c;
 169                         *p++ = 0;
 170                         while ((c = *p) == '\t' || c == ' ' || c == '\n')
 171                                 p++;
 172                         break;
 173                 }
 174         }
 175         *--t = '\0';
 176         return (p);
 177 }
 178
 179 static char *
 180 internal_function
 181 value(p)
 182         register char *p;
 183 {
 184
 185         return ((p = index(p, '=')) ? ++p : NULL);
 186 }
 187
 188 int
 189 setttyent()
 190 {
 191
 192         if (tf) {
 193                 (void)rewind(tf);
 194                 return (1);
 195         } else if ((tf = fopen(_PATH_TTYS, "rc"))) {
 196                 /* We do the locking ourselves.  */
 197                 __fsetlocking (tf, FSETLOCKING_BYCALLER);
 198                 return (1);
 199         }
 200         return (0);
 201 }
 202 libc_hidden_def (setttyent)
 203
 204 int
 205 endttyent()
 206 {
 207         int rval;
 208
 209         if (tf) {
 210                 rval = !(fclose(tf) == EOF);
 211                 tf = NULL;
 212                 return (rval);
 213         }
 214         return (1);
 215 }
 216 libc_hidden_def (endttyent)