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[unix-history] / usr / src / lib / libc / gen / getttyent.c

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
static char sccsid[] = "@(#)getttyent.c 5.1 (Berkeley) %G%";
#endif not lint

#include <stdio.h>
#include <strings.h>
#include <ttyent.h>

static char TTYFILE[] = "/etc/ttys";
static char EMPTY[] = "";
static FILE *tf = NULL;
#define LINE 256
static char line[LINE];
static struct ttyent tty;

setttyent()
{
       if (tf == NULL)
               tf = fopen(TTYFILE, "r");
       else
               rewind(tf);
}

endttyent()
{
       if (tf != NULL) {
               (void) fclose(tf);
               tf = NULL;
       }
}

#define QUOTED 1

/*
* Skip over the current field and 
* return a pointer to the next field.
*/
static char *
skip(p)
       register char *p;
{
       register int c;
       register int q = 0;

       for (; (c = *p) != '\0'; p++) {
               if (c == '"') {
                       q ^= QUOTED;    /* obscure, but nice */
                       continue;
               }
               if (q == QUOTED)
                       continue;
               if (c == '#') {
                       *p = '\0';
                       break;
               }
               if (c == '\t' || c == ' ' || c == '\n') {
                       *p++ = '\0';
                       while ((c = *p) == '\t' || c == ' ' || c == '\n')
                               p++;
                       break;
               }
       }
       return (p);
}

static char *
value(p)
       register char *p;
{
       if ((p = index(p,'=')) == 0)
               return(NULL);
       p++;                    /* get past the = sign */
       return(p);
}

/* get rid of quotes. */

static
qremove(p)
       register char *p;
{
       register char *t;

       for (t = p; *p; p++)
               if (*p != '"')
                       *t++ = *p;
       *t = '\0';
}

struct ttyent *
getttyent()
{
       register char *p;
       register int c;

       if (tf == NULL) {
               if ((tf = fopen(TTYFILE, "r")) == NULL)
                       return (NULL);
       }
       do {
               p = fgets(line, LINE, tf);
               if (p == NULL)
                       return (NULL);
               while ((c = *p) == '\t' || c == ' ' || c == '\n')
                       p++;
       } while (c == '\0' || c == '#');
       tty.ty_name = p;
       p = skip(p);
       tty.ty_getty = p;
       p = skip(p);
       tty.ty_type = p;
       p = skip(p);
       tty.ty_status = 0;
       tty.ty_window = EMPTY;
       for (; *p; p = skip(p)) {
               if (strncmp(p, "on", 2) == 0)
                       tty.ty_status |= TTY_ON;
               else if (strncmp(p, "off", 3) == 0)
                       tty.ty_status &= ~TTY_ON;
               else if (strncmp(p, "secure", 6) == 0)
                       tty.ty_status |= TTY_SECURE;
               else if (strncmp(p, "window", 6) == 0) {
                       if ((tty.ty_window = value(p)) == NULL)
                               tty.ty_window = EMPTY;
               } else
                       break;
       }
       tty.ty_comment = p;
       if (p = index(p, '\n'))
               *p = '\0';
       qremove(tty.ty_getty);
       qremove(tty.ty_window);
       qremove(tty.ty_comment);
       return(&tty);
}