source: trunk/athena/bin/lpr/printcap.c @ 7990

/*
 * 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[] = "@(#)printcap.c  5.1 (Berkeley) 6/6/85";
#endif not lint

#define MAXHOP  32      /* max number of tc= indirections */

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#ifdef HESIOD
#include <hesiod.h>
#include "lp.local.h"
#endif
#ifndef BUFSIZ
#define BUFSIZ  1024
#endif

/*
 * termcap - routines for dealing with the terminal capability data base
 *
 * BUG:         Should use a "last" pointer in tbuf, so that searching
 *              for capabilities alphabetically would not be a n**2/2
 *              process when large numbers of capabilities are given.
 * Note:        If we add a last pointer now we will screw up the
 *              tc capability. We really should compile termcap.
 *
 * Essentially all the work here is scanning and decoding escapes
 * in string capabilities.  We don't use stdio because the editor
 * doesn't, and because living w/o it is not hard.
 *
 * 4/13/87      Modified to use Hesiod name server iff HESIOD
 * SDyer        is defined.  If no printer capability is found in the
 * Athena       /etc/printcap file, Hesiod is queried for an alias for
 *              the given printer name and its capability.  In looking
 *              up the alias, Hesiod may also be queried for the host's
 *              cluster name.
 */

#define PRINTCAP

#ifdef PRINTCAP
#define tgetent pgetent
#define tskip   pskip
#define tgetstr pgetstr
#define tdecode pdecode
#define tgetnum pgetnum
#define tgetflag pgetflag
#define tdecode pdecode
#define tnchktc pnchktc
#define tnamatch pnamatch
#ifdef E_TERMCAP
#undef E_TERMCAP
#endif
#define E_TERMCAP "/etc/printcap"
#define V6
#endif

static  FILE *pfp = NULL;       /* printcap data base file pointer */
static  char *tbuf;
static  int hopcount;           /* detect infinite loops in termcap, init 0 */
char    *tskip();
char    *tgetstr();
char    *tdecode();
char    *getenv();

#ifdef HESIOD
/* Ask Hesiod if printer name is an alias.  If so,
 * put new name in "name" and return 1.  If not, return 0.
 * format:  -Pprinter[.cluster]
 */

int pralias(buf, name)
        char buf[];             /* buffer to put printer alias in */
        char *name;             /* name of printer to look up */
{
        char *e, temp[BUFSIZ/2];
#ifdef OLD_DEFAULT_ALIAS
        char **hv;
#endif
        char *getclus();
        
        strcpy(temp, name);
        /* If printer name == "default" then lookup based on LPR cluster info*/
        if(!strcmp(name, DEFLP)) {
            if ((e = getclus()) != NULL) {
                strcpy(buf, e);
                return(1);
            }
        }

#ifdef OLD_DEFAULT_ALIAS
        /* if not in "printer.cluster" format, look up cluster and append */
        if (strchr(name, '.') == NULL)
                if ((e = getenv("LPR")) != NULL) {
                        strcat(temp, ".");
                        strcat(temp, e);
                } else if ((e = getclus()) != NULL) {
                        strcat(temp, ".");
                        strcat(temp, e);
                }
        if ((hv = hes_resolve(temp, "lpralias")) != NULL &&
            strlen(*hv) < BUFSIZ/2) {
                strcpy(buf, *hv);
                return(1);
        }
#endif
        return (0);
}

/* Find this host's cluster name */
char *
getclus()
{
        static char cluster[BUFSIZ/2];
        char host[32];
        char **hv;
        int len = 4;  /* length of string "lpr " */

        gethostname(host, sizeof (host));
        if ((hv = hes_resolve(host, "cluster")) == NULL)
                return NULL;
        while (*hv) {
                if (strncmp(*hv, "lpr ", len) == 0) {
                        strcpy(cluster, *hv + len);
                        return cluster;
                        }
                ++hv;
        }
        return NULL;
}
        
/* 
 * Look for printer capability in Hesiod.
 * If eventually found, copy into "line" and return 1, otherwise
 * return 0.
 */

hpgetent(line, print)
        char *line;
        char *print;
{
        register char **hv;
        char **hes_resolve();

        tbuf = line;
        if ( (hv = hes_resolve(print, "pcap")) != NULL) {
                strcpy(line, *hv);
                return(tnchktc());
        }
        return 0;
}

#endif HESIOD

/*
 * Similar to tgetent except it returns the next entry instead of
 * doing a lookup.
 */
getprent(bp)
        register char *bp;
{
        register int c, skip = 0;

        if (pfp == NULL && (pfp = fopen(E_TERMCAP, "r")) == NULL)
                return(-1);
        tbuf = bp;
        for (;;) {
                switch (c = getc(pfp)) {
                case EOF:
                        fclose(pfp);
                        pfp = NULL;
                        return(0);
                case '\n':
                        if (bp == tbuf) {
                                skip = 0;
                                continue;
                        }
                        if (bp[-1] == '\\') {
                                bp--;
                                continue;
                        }
                        *bp = '\0';
                        return(1);
                case '#':
                        if (bp == tbuf)
                                skip++;
                default:
                        if (skip)
                                continue;
                        if (bp >= tbuf+BUFSIZ) {
                                write(2, "Termcap entry too long\n", 23);
                                *bp = '\0';
                                return(1);
                        }
                        *bp++ = c;
                }
        }
}

/*
 * Why do we close() before fclose()?
 *
 * endprent is called only by forked children, and with forked
 * children calling it under POSIX semantics there is a problem.
 *
 * When the forked child calls fclose(), fclose() (under POSIX) seeks
 * the file (and it's sharing the file descriptor with the parent) to
 * the byte after the last one read (as recorded in the FILE
 * structure) before close()ing. At the time of fork(), that pointer
 * is set to X. After the fork happens, the parent may get to run for
 * a while before the child does, and so it merrily continues reading
 * through the file, getting the pointer set to X+delta. But then the
 * child gets its turn, and seeks the pointer back to X. So the
 * parent's loop pointer has just been decremented, and may read
 * through the file potentially forever.
 *
 * Clearly we do not want the seek. So we close() the descriptor so
 * that fclose() (or exit() calling fclose()) can't muck with it. We
 * then do the fclose() anyway in the hope that it will free the memory
 * it was using.
 *
 * See Solaris stdio(3S) and fclose(3S) more details.
 */
endprent()
{
        if (pfp != NULL) {
                close(fileno(pfp));
                fclose(pfp);
        }
        pfp = NULL;
}

/*
 * Get an entry for terminal name in buffer bp,
 * from the termcap file.  Parse is very rudimentary;
 * we just notice escaped newlines.
 */

tgetent(bp, name)
        char *bp, *name;
{
        register char *cp;
        register int c;
        register int i = 0, cnt = 0;
        char ibuf[BUFSIZ];
#ifndef V6
        char *cp2;
#endif
        int tf;

        tbuf = bp;
        tf = 0;
#ifndef V6
        cp = getenv("TERMCAP");
        /*
         * TERMCAP can have one of two things in it. It can be the
         * name of a file to use instead of /etc/termcap. In this
         * case it better start with a "/". Or it can be an entry to
         * use so we don't have to read the file. In this case it
         * has to already have the newlines crunched out.
         */
        if (cp && *cp) {
                if (*cp!='/') {
                        cp2 = getenv("TERM");
                        if (cp2==(char *) 0 || strcmp(name,cp2)==0) {
                                strcpy(bp,cp);
                                return(tnchktc());
                        } else {
                                tf = open(E_TERMCAP, 0);
                        }
                } else
                        tf = open(cp, 0);
        }
        if (tf==0)
                tf = open(E_TERMCAP, 0);
#else
        tf = open(E_TERMCAP, 0);
#endif
        if (tf < 0)
                return (-1);
        for (;;) {
                cp = bp;
                for (;;) {
                        if (i == cnt) {
                                cnt = read(tf, ibuf, BUFSIZ);
                                if (cnt <= 0) {
                                        close(tf);
                                        return (0);
                                }
                                i = 0;
                        }
                        c = ibuf[i++];
                        if (c == '\n') {
                                if (cp > bp && cp[-1] == '\\'){
                                        cp--;
                                        continue;
                                }
                                break;
                        }
                        if (cp >= bp+BUFSIZ) {
                                write(2,"Termcap entry too long\n", 23);
                                break;
                        } else
                                *cp++ = c;
                }
                *cp = 0;

                /*
                 * The real work for the match.
                 */
                if (tnamatch(name)) {
                        close(tf);
                        return(tnchktc());
                }
        }
}

/*
 * tnchktc: check the last entry, see if it's tc=xxx. If so,
 * recursively find xxx and append that entry (minus the names)
 * to take the place of the tc=xxx entry. This allows termcap
 * entries to say "like an HP2621 but doesn't turn on the labels".
 * Note that this works because of the left to right scan.
 */
tnchktc()
{
        register char *p, *q;
        char tcname[16];        /* name of similar terminal */
        char tcbuf[BUFSIZ];
        char *holdtbuf = tbuf;
        int l;

        p = tbuf + strlen(tbuf) - 2;    /* before the last colon */
        while (*--p != ':')
                if (p<tbuf) {
                        write(2, "Bad termcap entry\n", 18);
                        return (0);
                }
        p++;
        /* p now points to beginning of last field */
        if (p[0] != 't' || p[1] != 'c')
                return(1);
        strcpy(tcname,p+3);
        q = tcname;
        while (*q && *q != ':')/* was while (q && ... *//* SPD Athena 4/15/87 */
                q++;
        *q = 0;
        if (++hopcount > MAXHOP) {
                write(2, "Infinite tc= loop\n", 18);
                return (0);
        }
#ifdef HESIOD
        if (hpgetent(tcbuf, tcname) != 1)
#else
        if (tgetent(tcbuf, tcname) != 1)
#endif
                return(0);
        for (q=tcbuf; *q != ':'; q++)
                ;
        l = p - holdtbuf + strlen(q);
        if (l > BUFSIZ) {
                write(2, "Termcap entry too long\n", 23);
                q[BUFSIZ - (p-tbuf)] = 0;
        }
        strcpy(p, q+1);
        tbuf = holdtbuf;
        return(1);
}

/*
 * Tnamatch deals with name matching.  The first field of the termcap
 * entry is a sequence of names separated by |'s, so we compare
 * against each such name.  The normal : terminator after the last
 * name (before the first field) stops us.
 */
tnamatch(np)
        char *np;
{
        register char *Np, *Bp;

        Bp = tbuf;
        if (*Bp == '#')
                return(0);
        for (;;) {
                for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
                        continue;
                if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
                        return (1);
                while (*Bp && *Bp != ':' && *Bp != '|')
                        Bp++;
                if (*Bp == 0 || *Bp == ':')
                        return (0);
                Bp++;
        }
}

/*
 * Skip to the next field.  Notice that this is very dumb, not
 * knowing about \: escapes or any such.  If necessary, :'s can be put
 * into the termcap file in octal.
 */
static char *
tskip(bp)
        register char *bp;
{

        while (*bp && *bp != ':')
                bp++;
        if (*bp == ':')
                bp++;
        return (bp);
}

/*
 * Return the (numeric) option id.
 * Numeric options look like
 *      li#80
 * i.e. the option string is separated from the numeric value by
 * a # character.  If the option is not found we return -1.
 * Note that we handle octal numbers beginning with 0.
 */
tgetnum(id)
        char *id;
{
        register int i, base;
        register char *bp = tbuf;

        for (;;) {
                bp = tskip(bp);
                if (*bp == 0)
                        return (-1);
                if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
                        continue;
                if (*bp == '@')
                        return(-1);
                if (*bp != '#')
                        continue;
                bp++;
                base = 10;
                if (*bp == '0')
                        base = 8;
                i = 0;
                while (isdigit(*bp))
                        i *= base, i += *bp++ - '0';
                return (i);
        }
}

/*
 * Handle a flag option.
 * Flag options are given "naked", i.e. followed by a : or the end
 * of the buffer.  Return 1 if we find the option, or 0 if it is
 * not given.
 */
tgetflag(id)
        char *id;
{
        register char *bp = tbuf;

        for (;;) {
                bp = tskip(bp);
                if (!*bp)
                        return (0);
                if (*bp++ == id[0] && *bp != 0 && *bp++ == id[1]) {
                        if (!*bp || *bp == ':')
                                return (1);
                        else if (*bp == '@')
                                return(0);
                }
        }
}

/*
 * Get a string valued option.
 * These are given as
 *      cl=^Z
 * Much decoding is done on the strings, and the strings are
 * placed in area, which is a ref parameter which is updated.
 * No checking on area overflow.
 */
char *
tgetstr(id, area)
        char *id, **area;
{
        register char *bp = tbuf;
        
        for (;;) {
                bp = tskip(bp);
                if (!*bp)
                        return (0);
                if (*bp++ != id[0] || *bp == 0 || *bp++ != id[1])
                        continue;
                if (*bp == '@')
                        return(0);
                if (*bp != '=')
                        continue;
                bp++;
                return (tdecode(bp, area));
        }
}

/*
 * Tdecode does the grung work to decode the
 * string capability escapes.
 */
static char *
tdecode(str, area)
        register char *str;
        char **area;
{
        register char *cp;
        register int c;
        register char *dp;
        int i;

        cp = *area;
        while ((c = *str++) && c != ':') {
                switch (c) {

                case '^':
                        c = *str++ & 037;
                        break;

                case '\\':
                        dp = "E\033^^\\\\::n\nr\rt\tb\bf\f";
                        c = *str++;
nextc:
                        if (*dp++ == c) {
                                c = *dp++;
                                break;
                        }
                        dp++;
                        if (*dp)
                                goto nextc;
                        if (isdigit(c)) {
                                c -= '0', i = 2;
                                do
                                        c <<= 3, c |= *str++ - '0';
                                while (--i && isdigit(*str));
                        }
                        break;
                }
                *cp++ = c;
        }
        *cp++ = 0;
        str = *area;
        *area = cp;
        return (str);
}