BSD 4_3_Net_2 release

[unix-history] / usr / src / bin / csh / csh.c

/*-
* Copyright (c) 1980, 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1991 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)csh.c       5.26 (Berkeley) 6/8/91";
#endif /* not lint */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <locale.h>
#include <unistd.h>
#if __STDC__
# include <stdarg.h>
#else
# include <varargs.h>
#endif

#include "csh.h"
#include "extern.h"
#include "pathnames.h"

extern bool MapsAreInited;
extern bool NLSMapsAreInited;

/*
* C Shell
*
* Bill Joy, UC Berkeley, California, USA
* October 1978, May 1980
*
* Jim Kulp, IIASA, Laxenburg, Austria
* April 1980
*
* Christos Zoulas, Cornell University
* June, 1991
*/

Char   *dumphist[] = {STRhistory, STRmh, 0, 0};
Char   *loadhist[] = {STRsource, STRmh, STRhistfile, 0};

int     nofile = 0;
bool    reenter = 0;
bool    nverbose = 0;
bool    nexececho = 0;
bool    quitit = 0;
bool    fast = 0;
bool    batch = 0;
bool    mflag = 0;
bool    prompt = 1;
bool    enterhist = 0;
bool    tellwhat = 0;

extern char **environ;

static int      srccat __P((Char *, Char *));
static int      srcfile __P((char *, bool, bool));
static void     phup __P((int));
static void     srcunit __P((int, bool, bool));
static void     mailchk __P((void));
static Char   **defaultpath __P((void));

int
main(argc, argv)
   int     argc;
   char  **argv;
{
   register Char *cp;
   register char *tcp;
   register int f;
   register char **tempv;
   struct sigvec osv;


   settimes();                 /* Immed. estab. timing base */

   /*
    * Initialize non constant strings
    */
#ifdef _PATH_BSHELL
   STR_BSHELL = SAVE(_PATH_BSHELL);
#endif
#ifdef _PATH_CSHELL
   STR_SHELLPATH = SAVE(_PATH_CSHELL);
#endif
   STR_environ = blk2short(environ);
   environ = short2blk(STR_environ);   /* So that we can free it */
   STR_WORD_CHARS = SAVE(WORD_CHARS);

   HIST = '!';
   HISTSUB = '^';
   word_chars = STR_WORD_CHARS;

   tempv = argv;
   if (eq(str2short(tempv[0]), STRaout))       /* A.out's are quittable */
       quitit = 1;
   uid = getuid();
   gid = getgid();
   /*
    * We are a login shell if: 1. we were invoked as -<something> and we had
    * no arguments 2. or we were invoked only with the -l flag
    */
   loginsh = (**tempv == '-' && argc == 1) ||
       (argc == 2 && tempv[1][0] == '-' && tempv[1][1] == 'l' &&
        tempv[1][2] == '\0');

   if (loginsh && **tempv != '-') {
       /*
        * Mangle the argv space
        */
       tempv[1][0] = '\0';
       tempv[1][1] = '\0';
       tempv[1] = NULL;
       for (tcp = *tempv; *tcp++;);
       for (tcp--; tcp >= *tempv; tcp--)
           tcp[1] = tcp[0];
       *++tcp = '-';
       argc--;
   }
   if (loginsh)
       (void) time(&chktim);

   AsciiOnly = 1;
#ifdef NLS
   (void) setlocale(LC_ALL, "");
   {
       int     k;

       for (k = 0200; k <= 0377 && !Isprint(k); k++);
       AsciiOnly = k > 0377;
   }
#else
   AsciiOnly = getenv("LANG") == NULL && getenv("LC_CTYPE") == NULL;
#endif                          /* NLS */

   /*
    * Move the descriptors to safe places. The variable didfds is 0 while we
    * have only FSH* to work with. When didfds is true, we have 0,1,2 and
    * prefer to use these.
    */
   initdesc();

   /*
    * Initialize the shell variables. ARGV and PROMPT are initialized later.
    * STATUS is also munged in several places. CHILD is munged when
    * forking/waiting
    */
   set(STRstatus, Strsave(STR0));

   if ((tcp = getenv("HOME")) != NULL)
       cp = SAVE(tcp);
   else
       cp = NULL;

   if (cp == NULL)
       fast = 1;               /* No home -> can't read scripts */
   else
       set(STRhome, cp);
   dinit(cp);                  /* dinit thinks that HOME == cwd in a login
                                * shell */
   /*
    * Grab other useful things from the environment. Should we grab
    * everything??
    */
   if ((tcp = getenv("LOGNAME")) != NULL ||
       (tcp = getenv("USER")) != NULL)
       set(STRuser, SAVE(tcp));
   if ((tcp = getenv("TERM")) != NULL)
       set(STRterm, SAVE(tcp));

   /*
    * Re-initialize path if set in environment
    */
   if ((tcp = getenv("PATH")) == NULL)
       set1(STRpath, defaultpath(), &shvhed);
   else
       importpath(SAVE(tcp));

   set(STRshell, Strsave(STR_SHELLPATH));

   doldol = putn((int) getpid());      /* For $$ */
   shtemp = Strspl(STRtmpsh, doldol);  /* For << */

   /*
    * Record the interrupt states from the parent process. If the parent is
    * non-interruptible our hand must be forced or we (and our children) won't
    * be either. Our children inherit termination from our parent. We catch it
    * only if we are the login shell.
    */
   /* parents interruptibility */
   (void) sigvec(SIGINT, NULL, &osv);
   parintr = (void (*) ()) osv.sv_handler;
   (void) sigvec(SIGTERM, NULL, &osv);
   parterm = (void (*) ()) osv.sv_handler;

   if (loginsh) {
       (void) signal(SIGHUP, phup);    /* exit processing on HUP */
       (void) signal(SIGXCPU, phup);   /* ...and on XCPU */
       (void) signal(SIGXFSZ, phup);   /* ...and on XFSZ */
   }

   /*
    * Process the arguments.
    * 
    * Note that processing of -v/-x is actually delayed till after script
    * processing.
    * 
    * We set the first character of our name to be '-' if we are a shell running
    * interruptible commands.  Many programs which examine ps'es use this to
    * filter such shells out.
    */
   argc--, tempv++;
   while (argc > 0 && (tcp = tempv[0])[0] == '-' && *++tcp != '\0' && !batch) {
       do
           switch (*tcp++) {

           case 0:             /* -    Interruptible, no prompt */
               prompt = 0;
               setintr = 1;
               nofile = 1;
               break;

           case 'b':           /* -b   Next arg is input file */
               batch = 1;
               break;

           case 'c':           /* -c   Command input from arg */
               if (argc == 1)
                   xexit(0);
               argc--, tempv++;
               arginp = SAVE(tempv[0]);
               prompt = 0;
               nofile = 1;
               break;

           case 'e':           /* -e   Exit on any error */
               exiterr = 1;
               break;

           case 'f':           /* -f   Fast start */
               fast = 1;
               break;

           case 'i':           /* -i   Interactive, even if !intty */
               intact = 1;
               nofile = 1;
               break;

           case 'm':           /* -m   read .cshrc (from su) */
               mflag = 1;
               break;

           case 'n':           /* -n   Don't execute */
               noexec = 1;
               break;

           case 'q':           /* -q   (Undoc'd) ... die on quit */
               quitit = 1;
               break;

           case 's':           /* -s   Read from std input */
               nofile = 1;
               break;

           case 't':           /* -t   Read one line from input */
               onelflg = 2;
               prompt = 0;
               nofile = 1;
               break;

           case 'v':           /* -v   Echo hist expanded input */
               nverbose = 1;   /* ... later */
               break;

           case 'x':           /* -x   Echo just before execution */
               nexececho = 1;  /* ... later */
               break;

           case 'V':           /* -V   Echo hist expanded input */
               setNS(STRverbose);      /* NOW! */
               break;

           case 'X':           /* -X   Echo just before execution */
               setNS(STRecho); /* NOW! */
               break;

       } while (*tcp);
       tempv++, argc--;
   }

   if (quitit)                 /* With all due haste, for debugging */
       (void) signal(SIGQUIT, SIG_DFL);

   /*
    * Unless prevented by -, -c, -i, -s, or -t, if there are remaining
    * arguments the first of them is the name of a shell file from which to
    * read commands.
    */
   if (nofile == 0 && argc > 0) {
       nofile = open(tempv[0], O_RDONLY);
       if (nofile < 0) {
           child = 1;          /* So this doesn't return */
           stderror(ERR_SYSTEM, tempv[0], strerror(errno));
       }
       ffile = SAVE(tempv[0]);
       /* 
        * Replace FSHIN. Handle /dev/std{in,out,err} specially
        * since once they are closed we cannot open them again.
        * In that case we use our own saved descriptors
        */
       if ((SHIN = dmove(nofile, FSHIN)) < 0) 
           switch(nofile) {
           case 0:
               SHIN = FSHIN;
               break;
           case 1:
               SHIN = FSHOUT;
               break;
           case 2:
               SHIN = FSHDIAG;
               break;
           default:
               stderror(ERR_SYSTEM, tempv[0], strerror(errno));
               break;
           }
       (void) ioctl(SHIN, FIOCLEX, NULL);
       prompt = 0;
        /* argc not used any more */ tempv++;
   }
   intty = isatty(SHIN);
   intty |= intact;
   if (intty || (intact && isatty(SHOUT))) {
       if (!batch && (uid != geteuid() || gid != getegid())) {
           errno = EACCES;
           child = 1;          /* So this doesn't return */
           stderror(ERR_SYSTEM, "csh", strerror(errno));
       }
   }
   /*
    * Decide whether we should play with signals or not. If we are explicitly
    * told (via -i, or -) or we are a login shell (arg0 starts with -) or the
    * input and output are both the ttys("csh", or "csh</dev/ttyx>/dev/ttyx")
    * Note that in only the login shell is it likely that parent may have set
    * signals to be ignored
    */
   if (loginsh || intact || intty && isatty(SHOUT))
       setintr = 1;
   settell();
   /*
    * Save the remaining arguments in argv.
    */
   setq(STRargv, blk2short(tempv), &shvhed);

   /*
    * Set up the prompt.
    */
   if (prompt) {
       set(STRprompt, Strsave(uid == 0 ? STRsymhash : STRsymcent));
       /* that's a meta-questionmark */
       set(STRprompt2, Strsave(STRmquestion));
   }

   /*
    * If we are an interactive shell, then start fiddling with the signals;
    * this is a tricky game.
    */
   shpgrp = getpgrp();
   opgrp = tpgrp = -1;
   if (setintr) {
       **argv = '-';
       if (!quitit)            /* Wary! */
           (void) signal(SIGQUIT, SIG_IGN);
       (void) signal(SIGINT, pintr);
       (void) sigblock(sigmask(SIGINT));
       (void) signal(SIGTERM, SIG_IGN);
       if (quitit == 0 && arginp == 0) {
           (void) signal(SIGTSTP, SIG_IGN);
           (void) signal(SIGTTIN, SIG_IGN);
           (void) signal(SIGTTOU, SIG_IGN);
           /*
            * Wait till in foreground, in case someone stupidly runs csh &
            * dont want to try to grab away the tty.
            */
           if (isatty(FSHDIAG))
               f = FSHDIAG;
           else if (isatty(FSHOUT))
               f = FSHOUT;
           else if (isatty(OLDSTD))
               f = OLDSTD;
           else
               f = -1;
   retry:
           if ((tpgrp = tcgetpgrp(f)) != -1) {
               if (tpgrp != shpgrp) {
                   sig_t old = signal(SIGTTIN, SIG_DFL);
                   (void) kill(0, SIGTTIN);
                   (void) signal(SIGTTIN, old);
                   goto retry;
               }
               opgrp = shpgrp;
               shpgrp = getpid();
               tpgrp = shpgrp;
               /*
                * Setpgid will fail if we are a session leader and 
                * mypid == mypgrp (POSIX 4.3.3)
                */
               if (opgrp != shpgrp)
                   if (setpgid(0, shpgrp) == -1)
                       goto notty;
               /*
                * We do that after we set our process group, to make sure
                * that the process group belongs to a process in the same
                * session as the tty (our process and our group) (POSIX 7.2.4)
                */
               if (tcsetpgrp(f, shpgrp) == -1)
                   goto notty;
               (void) ioctl(dcopy(f, FSHTTY), FIOCLEX, NULL);
           }
           if (tpgrp == -1) {
notty:
               xprintf("Warning: no access to tty (%s).\n", strerror(errno));
               xprintf("Thus no job control in this shell.\n");
           }
       }
   }
   if ((setintr == 0) && (parintr == SIG_DFL))
       setintr = 1;
   (void) signal(SIGCHLD, pchild);     /* while signals not ready */

   /*
    * Set an exit here in case of an interrupt or error reading the shell
    * start-up scripts.
    */
   reenter = setexit();        /* PWP */
   haderr = 0;                 /* In case second time through */
   if (!fast && reenter == 0) {
       /* Will have value(STRhome) here because set fast if don't */
       {
           int     osetintr = setintr;
           sigset_t omask = sigblock(sigmask(SIGINT));

           setintr = 0;
#ifdef _PATH_DOTCSHRC
           (void) srcfile(_PATH_DOTCSHRC, 0, 0);
#endif
           if (!fast && !arginp && !onelflg)
               dohash();
#ifdef _PATH_DOTLOGIN
           if (loginsh)
               (void) srcfile(_PATH_DOTLOGIN, 0, 0);
#endif
           (void) sigsetmask(omask);
           setintr = osetintr;
       }
       (void) srccat(value(STRhome), STRsldotcshrc);

       if (!fast && !arginp && !onelflg && !havhash)
           dohash();
       if (loginsh)
             (void) srccat(value(STRhome), STRsldotlogin);
       dosource(loadhist);
   }

   /*
    * Now are ready for the -v and -x flags
    */
   if (nverbose)
       setNS(STRverbose);
   if (nexececho)
       setNS(STRecho);

   /*
    * All the rest of the world is inside this call. The argument to process
    * indicates whether it should catch "error unwinds".  Thus if we are a
    * interactive shell our call here will never return by being blown past on
    * an error.
    */
   process(setintr);

   /*
    * Mop-up.
    */
   if (intty) {
       if (loginsh) {
           xprintf("logout\n");
           (void) close(SHIN);
           child = 1;
           goodbye();
       }
       else {
           xprintf("exit\n");
       }
   }
   rechist();
   exitstat();
   return (0);
}

void
untty()
{
   if (tpgrp > 0) {
       (void) setpgid(0, opgrp);
       (void) tcsetpgrp(FSHTTY, opgrp);
   }
}

void
importpath(cp)
   Char   *cp;
{
   register int i = 0;
   register Char *dp;
   register Char **pv;
   int     c;

   for (dp = cp; *dp; dp++)
       if (*dp == ':')
           i++;
   /*
    * i+2 where i is the number of colons in the path. There are i+1
    * directories in the path plus we need room for a zero terminator.
    */
   pv = (Char **) xcalloc((size_t) (i + 2), sizeof(Char **));
   dp = cp;
   i = 0;
   if (*dp)
       for (;;) {
           if ((c = *dp) == ':' || c == 0) {
               *dp = 0;
               pv[i++] = Strsave(*cp ? cp : STRdot);
               if (c) {
                   cp = dp + 1;
                   *dp = ':';
               }
               else
                   break;
           }
           dp++;
       }
   pv[i] = 0;
   set1(STRpath, pv, &shvhed);
}

/*
* Source to the file which is the catenation of the argument names.
*/
static int
srccat(cp, dp)
   Char   *cp, *dp;
{
   register Char *ep = Strspl(cp, dp);
   char   *ptr = short2str(ep);

   xfree((ptr_t) ep);
   return srcfile(ptr, mflag ? 0 : 1, 0);
}

/*
* Source to a file putting the file descriptor in a safe place (> 2).
*/
static int
srcfile(f, onlyown, flag)
   char   *f;
   bool    onlyown, flag;
{
   register int unit;

   if ((unit = open(f, O_RDONLY)) == -1)
       return 0;
   unit = dmove(unit, -1);

   (void) ioctl(unit, FIOCLEX, NULL);
   srcunit(unit, onlyown, flag);
   return 1;
}

/*
* Source to a unit.  If onlyown it must be our file or our group or
* we don't chance it.  This occurs on ".cshrc"s and the like.
*/
int     insource;
static void
srcunit(unit, onlyown, hflg)
   register int unit;
   bool    onlyown, hflg;
{
   /* We have to push down a lot of state here */
   /* All this could go into a structure */
   int     oSHIN = -1, oldintty = intty, oinsource = insource;
   struct whyle *oldwhyl = whyles;
   Char   *ogointr = gointr, *oarginp = arginp;
   Char   *oevalp = evalp, **oevalvec = evalvec;
   int     oonelflg = onelflg;
   bool    oenterhist = enterhist;
   char    OHIST = HIST;
   bool    otell = cantell;

   struct Bin saveB;
   sigset_t omask;
   jmp_buf oldexit;

   /* The (few) real local variables */
   int     my_reenter;

   if (unit < 0)
       return;
   if (didfds)
       donefds();
   if (onlyown) {
       struct stat stb;

       if (fstat(unit, &stb) < 0) {
           (void) close(unit);
           return;
       }
   }

   /*
    * There is a critical section here while we are pushing down the input
    * stream since we have stuff in different structures. If we weren't
    * careful an interrupt could corrupt SHIN's Bin structure and kill the
    * shell.
    * 
    * We could avoid the critical region by grouping all the stuff in a single
    * structure and pointing at it to move it all at once.  This is less
    * efficient globally on many variable references however.
    */
   insource = 1;
   getexit(oldexit);
   omask = 0;

   if (setintr)
       omask = sigblock(sigmask(SIGINT));
   /* Setup the new values of the state stuff saved above */
   bcopy((char *) &B, (char *) &(saveB), sizeof(B));
   fbuf = NULL;
   fseekp = feobp = fblocks = 0;
   oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
   intty = isatty(SHIN), whyles = 0, gointr = 0;
   evalvec = 0;
   evalp = 0;
   enterhist = hflg;
   if (enterhist)
       HIST = '\0';

   /*
    * Now if we are allowing commands to be interrupted, we let ourselves be
    * interrupted.
    */
   if (setintr)
       (void) sigsetmask(omask);
   settell();

   if ((my_reenter = setexit()) == 0)
       process(0);             /* 0 -> blow away on errors */

   if (setintr)
       (void) sigsetmask(omask);
   if (oSHIN >= 0) {
       register int i;

       /* We made it to the new state... free up its storage */
       /* This code could get run twice but xfree doesn't care */
       for (i = 0; i < fblocks; i++)
           xfree((ptr_t) fbuf[i]);
       xfree((ptr_t) fbuf);

       /* Reset input arena */
       bcopy((char *) &(saveB), (char *) &B, sizeof(B));

       (void) close(SHIN), SHIN = oSHIN;
       arginp = oarginp, onelflg = oonelflg;
       evalp = oevalp, evalvec = oevalvec;
       intty = oldintty, whyles = oldwhyl, gointr = ogointr;
       if (enterhist)
           HIST = OHIST;
       enterhist = oenterhist;
       cantell = otell;
   }

   resexit(oldexit);
   /*
    * If process reset() (effectively an unwind) then we must also unwind.
    */
   if (my_reenter)
       stderror(ERR_SILENT);
   insource = oinsource;
}

void
rechist()
{
   Char    buf[BUFSIZ];
   int     fp, ftmp, oldidfds;

   if (!fast) {
       if (value(STRsavehist)[0] == '\0')
           return;
       (void) Strcpy(buf, value(STRhome));
       (void) Strcat(buf, STRsldthist);
       fp = creat(short2str(buf), 0600);
       if (fp == -1)
           return;
       oldidfds = didfds;
       didfds = 0;
       ftmp = SHOUT;
       SHOUT = fp;
       (void) Strcpy(buf, value(STRsavehist));
       dumphist[2] = buf;
       dohist(dumphist);
       (void) close(fp);
       SHOUT = ftmp;
       didfds = oldidfds;
   }
}

void
goodbye()
{
   rechist();

   if (loginsh) {
       (void) signal(SIGQUIT, SIG_IGN);
       (void) signal(SIGINT, SIG_IGN);
       (void) signal(SIGTERM, SIG_IGN);
       setintr = 0;            /* No interrupts after "logout" */
       if (!(adrof(STRlogout)))
           set(STRlogout, STRnormal);
#ifdef _PATH_DOTLOGOUT
       (void) srcfile(_PATH_DOTLOGOUT, 0, 0);
#endif
       if (adrof(STRhome))
           (void) srccat(value(STRhome), STRsldtlogout);
   }
   exitstat();
}

void
exitstat()
{

#ifdef PROF
   monitor(0);
#endif
   /*
    * Note that if STATUS is corrupted (i.e. getn bombs) then error will exit
    * directly because we poke child here. Otherwise we might continue
    * unwarrantedly (sic).
    */
   child = 1;
   xexit(getn(value(STRstatus)));
}

/*
* in the event of a HUP we want to save the history
*/
static void
phup(sig)
int sig;
{
   rechist();
   xexit(sig);
}

Char   *jobargv[2] = {STRjobs, 0};

/*
* Catch an interrupt, e.g. during lexical input.
* If we are an interactive shell, we reset the interrupt catch
* immediately.  In any case we drain the shell output,
* and finally go through the normal error mechanism, which
* gets a chance to make the shell go away.
*/
/* ARGSUSED */
void
pintr(notused)
       int notused;
{
   pintr1(1);
}

void
pintr1(wantnl)
   bool    wantnl;
{
   register Char **v;
   sigset_t omask;

   omask = sigblock((sigset_t) 0);
   if (setintr) {
       (void) sigsetmask(omask & ~sigmask(SIGINT));
       if (pjobs) {
           pjobs = 0;
           xprintf("\n");
           dojobs(jobargv);
           stderror(ERR_NAME | ERR_INTR);
       }
   }
   (void) sigsetmask(omask & ~sigmask(SIGCHLD));
   draino();
   (void) endpwent();

   /*
    * If we have an active "onintr" then we search for the label. Note that if
    * one does "onintr -" then we shan't be interruptible so we needn't worry
    * about that here.
    */
   if (gointr) {
       search(T_GOTO, 0, gointr);
       timflg = 0;
       if (v = pargv)
           pargv = 0, blkfree(v);
       if (v = gargv)
           gargv = 0, blkfree(v);
       reset();
   }
   else if (intty && wantnl) {
       (void) putraw('\r');
       (void) putraw('\n');
   }
   stderror(ERR_SILENT);
}

/*
* Process is the main driving routine for the shell.
* It runs all command processing, except for those within { ... }
* in expressions (which is run by a routine evalav in sh.exp.c which
* is a stripped down process), and `...` evaluation which is run
* also by a subset of this code in sh.glob.c in the routine backeval.
*
* The code here is a little strange because part of it is interruptible
* and hence freeing of structures appears to occur when none is necessary
* if this is ignored.
*
* Note that if catch is not set then we will unwind on any error.
* If an end-of-file occurs, we return.
*/
void
process(catch)
   bool    catch;
{
   jmp_buf osetexit;
   struct command *t;

   getexit(osetexit);
   for (;;) {
       pendjob();
       paraml.next = paraml.prev = &paraml;
       paraml.word = STRNULL;
       t = 0;
       (void) setexit();
       justpr = enterhist;     /* execute if not entering history */

       /*
        * Interruptible during interactive reads
        */
       if (setintr)
           (void) sigsetmask(sigblock((sigset_t) 0) & ~sigmask(SIGINT));

       /*
        * For the sake of reset()
        */
       freelex(&paraml);
       freesyn(t);
       t = 0;

       if (haderr) {
           if (!catch) {
               /* unwind */
               doneinp = 0;
               resexit(osetexit);
               reset();
           }
           haderr = 0;
           /*
            * Every error is eventually caught here or the shell dies.  It is
            * at this point that we clean up any left-over open files, by
            * closing all but a fixed number of pre-defined files.  Thus
            * routines don't have to worry about leaving files open due to
            * deeper errors... they will get closed here.
            */
           closem();
           continue;
       }
       if (doneinp) {
           doneinp = 0;
           break;
       }
       if (chkstop)
           chkstop--;
       if (neednote)
           pnote();
       if (intty && prompt && evalvec == 0) {
           mailchk();
           /*
            * If we are at the end of the input buffer then we are going to
            * read fresh stuff. Otherwise, we are rereading input and don't
            * need or want to prompt.
            */
           if (fseekp == feobp)
               printprompt();
           flush();
       }
       if (seterr) {
           xfree((ptr_t) seterr);
           seterr = NULL;
       }

       /*
        * Echo not only on VERBOSE, but also with history expansion. If there
        * is a lexical error then we forego history echo.
        */
       if (lex(&paraml) && !seterr && intty || adrof(STRverbose)) {
           haderr = 1;
           prlex(&paraml);
           haderr = 0;
       }

       /*
        * The parser may lose space if interrupted.
        */
       if (setintr)
           (void) sigblock(sigmask(SIGINT));

       /*
        * Save input text on the history list if reading in old history, or it
        * is from the terminal at the top level and not in a loop.
        * 
        * PWP: entry of items in the history list while in a while loop is done
        * elsewhere...
        */
       if (enterhist || catch && intty && !whyles)
           savehist(&paraml);

       /*
        * Print lexical error messages, except when sourcing history lists.
        */
       if (!enterhist && seterr)
           stderror(ERR_OLD);

       /*
        * If had a history command :p modifier then this is as far as we
        * should go
        */
       if (justpr)
           reset();

       alias(&paraml);

       /*
        * Parse the words of the input into a parse tree.
        */
       t = syntax(paraml.next, &paraml, 0);
       if (seterr)
           stderror(ERR_OLD);

       execute(t, (tpgrp > 0 ? tpgrp : -1), NULL, NULL);

       /*
        * Made it!
        */
       freelex(&paraml);
       freesyn(t);
   }
   resexit(osetexit);
}

void
dosource(t)
   register Char **t;
{
   register Char *f;
   bool    hflg = 0;
   Char    buf[BUFSIZ];

   t++;
   if (*t && eq(*t, STRmh)) {
       if (*++t == NULL)
           stderror(ERR_NAME | ERR_HFLAG);
       hflg++;
   }
   (void) Strcpy(buf, *t);
   f = globone(buf, G_ERROR);
   (void) strcpy((char *) buf, short2str(f));
   xfree((ptr_t) f);
   if (!srcfile((char *) buf, 0, hflg) && !hflg)
       stderror(ERR_SYSTEM, (char *) buf, strerror(errno));
}

/*
* Check for mail.
* If we are a login shell, then we don't want to tell
* about any mail file unless its been modified
* after the time we started.
* This prevents us from telling the user things he already
* knows, since the login program insists on saying
* "You have mail."
*/
static void
mailchk()
{
   register struct varent *v;
   register Char **vp;
   time_t  t;
   int     intvl, cnt;
   struct stat stb;
   bool    new;

   v = adrof(STRmail);
   if (v == 0)
       return;
   (void) time(&t);
   vp = v->vec;
   cnt = blklen(vp);
   intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
   if (intvl < 1)
       intvl = 1;
   if (chktim + intvl > t)
       return;
   for (; *vp; vp++) {
       if (stat(short2str(*vp), &stb) < 0)
           continue;
       new = stb.st_mtime > time0.tv_sec;
       if (stb.st_size == 0 || stb.st_atime > stb.st_mtime ||
           (stb.st_atime < chktim && stb.st_mtime < chktim) ||
           loginsh && !new)
           continue;
       if (cnt == 1)
           xprintf("You have %smail.\n", new ? "new " : "");
       else
           xprintf("%s in %s.\n", new ? "New mail" : "Mail", short2str(*vp));
   }
   chktim = t;
}

/*
* Extract a home directory from the password file
* The argument points to a buffer where the name of the
* user whose home directory is sought is currently.
* We write the home directory of the user back there.
*/
int
gethdir(home)
   Char   *home;
{
   Char   *h;
   struct passwd *pw;

   /*
    * Is it us?
    */
   if (*home == '\0') {
       if (h = value(STRhome)) {
           (void) Strcpy(home, h);
           return 0;
       }
       else
           return 1;
   }

   if (pw = getpwnam(short2str(home))) {
       (void) Strcpy(home, str2short(pw->pw_dir));
       return 0;
   }
   else
       return 1;
}

/*
* Move the initial descriptors to their eventual
* resting places, closin all other units.
*/
void
initdesc()
{

   didfds = 0;                 /* 0, 1, 2 aren't set up */
   (void) ioctl(SHIN = dcopy(0, FSHIN), FIOCLEX, NULL);
   (void) ioctl(SHOUT = dcopy(1, FSHOUT), FIOCLEX, NULL);
   (void) ioctl(SHDIAG = dcopy(2, FSHDIAG), FIOCLEX, NULL);
   (void) ioctl(OLDSTD = dcopy(SHIN, FOLDSTD), FIOCLEX, NULL);
   closem();
}


void
#ifdef PROF
done(i)
#else
xexit(i)
#endif
   int     i;
{
   untty();
   _exit(i);
}

static Char **
defaultpath()
{
   char   *ptr;
   Char  **blk, **blkp;
   struct stat stb;

   blkp = blk = (Char **) xmalloc((size_t) sizeof(Char *) * 10);

#define DIRAPPEND(a)  \
       if (stat(ptr = a, &stb) == 0 && (stb.st_mode & S_IFMT) == S_IFDIR) \
               *blkp++ = SAVE(ptr)

   DIRAPPEND(_PATH_BIN);
   DIRAPPEND(_PATH_USRBIN);

#undef DIRAPPEND

   *blkp++ = Strsave(STRdot);
   *blkp = NULL;
   return (blk);
}

void
printprompt()
{
   register Char *cp;

   if (!whyles) {
       for (cp = value(STRprompt); *cp; cp++)
           if (*cp == HIST)
               xprintf("%d", eventno + 1);
           else {
               if (*cp == '\\' && cp[1] == HIST)
                   cp++;
               xputchar(*cp | QUOTE);
           }
   }
   else
       /*
        * Prompt for forward reading loop body content.
        */
       xprintf("? ");
   flush();
}