gen/common/getttyent.c

/*
 * Copyright (c) 1985 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"


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

static char *TTYFILE = "/etc/ttytab";
#define LINE 256
static struct _ttyentjunk {
    char    zapchar;
    FILE    *tf;
    char    line[LINE];
    struct  ttyent tty;
} *__ttyentjunk, *_ttyentjunk(void);

static struct _ttyentjunk *
_ttyentjunk(void)
{

    if (__ttyentjunk == 0)
        __ttyentjunk = (struct _ttyentjunk *)calloc(1, sizeof (struct _ttyentjunk));
    return (__ttyentjunk);
}

void
setttyent(void)
{
    struct _ttyentjunk *t = _ttyentjunk();

    if (t == 0)
        return;
    if (t->tf == NULL)
        t->tf = fopen(TTYFILE, "r");
    else
        rewind(t->tf);
}

void
endttyent(void)
{
    struct _ttyentjunk *t = _ttyentjunk();

    if (t == 0)
        return;
    if (t->tf != NULL) {
        (void) fclose(t->tf);
        t->tf = NULL;
    }
}

#define QUOTED  1

/*
 * Skip over the current field, removing quotes,
 * and return a pointer to the next field.
 */
static char *
skip(char *p)
{
    struct _ttyentjunk *t = _ttyentjunk();
    char *cp = p;
    int c;
    int q = 0;

    if (t == 0)
        return (0);
    for (; (c = *p) != '\0'; p++) {
        if (c == '"') {
            q ^= QUOTED;    /* obscure, but nice */
            continue;
        }
        if (q == QUOTED && *p == '\\' && *(p+1) == '"')
            p++;
        *cp++ = *p;
        if (q == QUOTED)
            continue;
        if (c == '#') {
            t->zapchar = c;
            *p = 0;
            break;
        }
        if (c == '\t' || c == ' ' || c == '\n') {
            t->zapchar = c;
            *p++ = 0;
            while ((c = *p) == '\t' || c == ' ' || c == '\n')
                p++;
            break;
        }
    }
    *--cp = '\0';
    return (p);
}

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

struct ttyent *
getttyent(void)
{
    struct _ttyentjunk *t = _ttyentjunk();
    char *p;
    int c;

    if (t == 0)
        return (NULL);
    if (t->tf == NULL) {
        if ((t->tf = fopen(TTYFILE, "r")) == NULL)
            return (NULL);
    }
    do {
        p = fgets(t->line, LINE, t->tf);
        if (p == NULL)
            return (NULL);
        while ((c = *p) == '\t' || c == ' ' || c == '\n')
            p++;
    } while (c == '\0' || c == '#');
    t->zapchar = 0;
    t->tty.ty_name = p;
    p = skip(p);
    t->tty.ty_getty = p;
    p = skip(p);
    t->tty.ty_type = p;
    p = skip(p);
    t->tty.ty_status = 0;
    t->tty.ty_window = NULL;
    for (; *p; p = skip(p)) {
#define space(x) ((c = p[x]) == ' ' || c == '\t' || c == '\n')
        if (strncmp(p, "on", 2) == 0 && space(2))
            t->tty.ty_status |= TTY_ON;
        else if (strncmp(p, "off", 3) == 0 && space(3))
            t->tty.ty_status &= ~TTY_ON;
        else if (strncmp(p, "secure", 6) == 0 && space(6))
            t->tty.ty_status |= TTY_SECURE;
        else if (strncmp(p, "local", 5) == 0 && space(5))
            t->tty.ty_status |= TTY_LOCAL;
        else if (strncmp(p, "window=", 7) == 0)
            t->tty.ty_window = value(p);
        else
            break;
    }
    if (t->zapchar == '#' || *p == '#')
        while ((c = *++p) == ' ' || c == '\t')
            ;
    t->tty.ty_comment = p;
    if (*p == 0)
        t->tty.ty_comment = 0;
    if (p = index(p, '\n'))
        *p = '\0';
    return (&t->tty);
}