csh.c

早期freebsd实现

/*-
 * Copyright (c) 1980, 1991, 1993
 *	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
static char copyright[] =
"@(#) Copyright (c) 1980, 1991, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)csh.c	8.2 (Berkeley) 10/12/93";
#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>
#include <vis.h>
#if __STDC__
# include <stdarg.h>
#else
# include <varargs.h>
#endif

#include "csh.h"
#include "proc.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, STRtildothist, 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	readf __P((void *, char *, int));
static fpos_t	seekf __P((void *, fpos_t, int));
static int	writef __P((void *, const char *, int));
static int	closef __P((void *));
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;

    cshin = stdin;
    cshout = stdout;
    csherr = stderr;

    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();
    euid = geteuid();
    egid = getegid();
    /*
     * 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++;)
	    continue;
	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++)
	    continue;
	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();
    /*
     * XXX: This is to keep programs that use stdio happy.
     *	    what we really want is freunopen() ....
     *	    Closing cshin cshout and csherr (which are really stdin stdout
     *	    and stderr at this point and then reopening them in the same order
     *	    gives us again stdin == cshin stdout == cshout and stderr == csherr.
     *	    If that was not the case builtins like printf that use stdio
     *	    would break. But in any case we could fix that with memcpy and
     *	    a bit of pointer manipulation...
     *	    Fortunately this is not needed under the current implementation
     *	    of stdio.
     */
    (void) fclose(cshin);
    (void) fclose(cshout);
    (void) fclose(csherr);
    if (!(cshin  = funopen((void *) &SHIN,  readf, writef, seekf, closef)))
	exit(1);
    if (!(cshout = funopen((void *) &SHOUT, readf, writef, seekf, closef)))
	exit(1);
    if (!(csherr = funopen((void *) &SHERR, readf, writef, seekf, closef)))
	exit(1);
    (void) setvbuf(cshin,  NULL, _IOLBF, 0);
    (void) setvbuf(cshout, NULL, _IOLBF, 0);
    (void) setvbuf(csherr, NULL, _IOLBF, 0);

    /*
     * 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 = FSHERR;
		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 != euid || gid != egid)) {
	    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);