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