/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * 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. 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.
 */

#include <stdio.h>
#include <signal.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <locale.h>
#include <errno.h>

#include "shell.h"
#include "main.h"
#include "mail.h"
#include "options.h"
#include "output.h"
#include "parser.h"
#include "nodes.h"
#include "expand.h"
#include "eval.h"
#include "jobs.h"
#include "input.h"
#include "trap.h"
#include "var.h"
#include "show.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "exec.h"
#include "cd.h"
#include "redir.h"
#include "builtins.h"
#ifndef NO_HISTORY
#include "myhistedit.h"
#endif

int rootpid;
int rootshell;
struct jmploc main_handler;
int localeisutf8, initial_localeisutf8;

static void reset(void);
static void cmdloop(int);
static void read_profile(const char *);
static char *find_dot_file(char *);

/*
 * Main routine.  We initialize things, parse the arguments, execute
 * profiles if we're a login shell, and then call cmdloop to execute
 * commands.  The setjmp call sets up the location to jump to when an
 * exception occurs.  When an exception occurs the variable "state"
 * is used to figure out how far we had gotten.
 */

int
main(int argc, char *argv[])
{
        /*
         * As smark is accessed after a longjmp, it cannot be a local in main().
         * The C standard specifies that the values of non-volatile local
         * variables are unspecified after a jump if modified between the
         * setjmp and longjmp.
         */
        static struct stackmark smark, smark2;
        volatile int state;
        char *shinit;
        int login;

        (void) setlocale(LC_ALL, "");
        initcharset();
        state = 0;
        if (setjmp(main_handler.loc)) {
                if (state == 0 || iflag == 0 || ! rootshell ||
                    exception == EXEXIT)
                        exitshell(exitstatus);
                reset();
                if (exception == EXINT)
                        out2fmt_flush("\n");
                popstackmark(&smark);
                FORCEINTON;                             /* enable interrupts */
                if (state == 1)
                        goto state1;
                else if (state == 2)
                        goto state2;
                else if (state == 3)
                        goto state3;
                else
                        goto state4;
        }
        handler = &main_handler;
#ifdef DEBUG
        opentrace();
        trputs("Shell args:  ");  trargs(argv);
#endif
        rootpid = getpid();
        rootshell = 1;
        INTOFF;
        initvar();
        setstackmark(&smark);
        setstackmark(&smark2);
        login = procargs(argc, argv);
        trap_init();
        pwd_init(iflag);
        INTON;
        if (iflag)
                chkmail(1);
        if (login) {
                state = 1;
                read_profile("/etc/profile");
state1:
                state = 2;
                if (privileged == 0)
                        read_profile("${HOME-}/.profile");
                else
                        read_profile("/etc/suid_profile");
        }
state2:
        state = 3;
        if (!privileged && iflag) {
                if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
                        state = 3;
                        read_profile(shinit);
                }
        }
#ifndef NO_HISTORY
        if (iflag)
                histload();
#endif
state3:
        state = 4;
        popstackmark(&smark2);
        if (minusc) {
                evalstring(minusc, sflag ? 0 : EV_EXIT);
        }
state4:
        if (sflag || minusc == NULL) {
                cmdloop(1);
        }
        exitshell(exitstatus);
        /*NOTREACHED*/
        return 0;
}

static void
reset(void)
{
        reseteval();
        resetinput();
}

/*
 * Read and execute commands.  "Top" is nonzero for the top level command
 * loop; it turns on prompting if the shell is interactive.
 */

static void
cmdloop(int top)
{
        union node *n;
        struct stackmark smark;
        int inter;
        int numeof = 0;

        TRACE(("cmdloop(%d) called\n", top));
        setstackmark(&smark);
        for (;;) {
                if (pendingsig)
                        dotrap();
                inter = 0;
                if (iflag && top) {
                        inter++;
                        showjobs(1, SHOWJOBS_DEFAULT);
                        chkmail(0);
                        flushout(&output);
                }
                n = parsecmd(inter);
                /* showtree(n); DEBUG */
                if (n == NEOF) {
                        if (!top || numeof >= 50)
                                break;
                        if (!stoppedjobs()) {
                                if (!Iflag)
                                        break;
                                out2fmt_flush("\nUse \"exit\" to leave shell.\n");
                        }
                        numeof++;
                } else if (n != NULL && nflag == 0) {
                        job_warning = (job_warning == 2) ? 1 : 0;
                        numeof = 0;
                        evaltree(n, 0);
                }
                popstackmark(&smark);
                setstackmark(&smark);
                if (evalskip != 0) {
                        if (evalskip == SKIPRETURN)
                                evalskip = 0;
                        break;
                }
        }
        popstackmark(&smark);
        if (top && iflag) {
                out2c('\n');
                flushout(out2);
        }
}



/*
 * Read /etc/profile or .profile.  Return on error.
 */

static void
read_profile(const char *name)
{
        int fd;
        const char *expandedname;
        int oflags = O_RDONLY | O_CLOEXEC;

        if (verifyflag)
                oflags |= O_VERIFY;

        expandedname = expandstr(name);
        if (expandedname == NULL)
                return;
        INTOFF;
        if ((fd = open(expandedname, oflags)) >= 0)
                setinputfd(fd, 1);
        INTON;
        if (fd < 0)
                return;
        cmdloop(0);
        popfile();
}



/*
 * Read a file containing shell functions.
 */

void
readcmdfile(const char *name, int verify)
{
        setinputfile(name, 1, verify);
        cmdloop(0);
        popfile();
}



/*
 * Take commands from a file.  To be compatible we should do a path
 * search for the file, which is necessary to find sub-commands.
 */


static char *
find_dot_file(char *basename)
{
        char *fullname;
        const char *opt;
        const char *path = pathval();
        struct stat statb;

        /* don't try this for absolute or relative paths */
        if( strchr(basename, '/'))
                return basename;

        while ((fullname = padvance(&path, &opt, basename)) != NULL) {
                if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
                        /*
                         * Don't bother freeing here, since it will
                         * be freed by the caller.
                         */
                        return fullname;
                }
                stunalloc(fullname);
        }
        return basename;
}

int
dotcmd(int argc, char **argv)
{
        char *filename, *fullname;

        if (argc < 2)
                error("missing filename");

        exitstatus = 0;

        /*
         * Because we have historically not supported any options,
         * only treat "--" specially.
         */
        filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];

        fullname = find_dot_file(filename);
        setinputfile(fullname, 1, -1 /* verify */);
        commandname = fullname;
        cmdloop(0);
        popfile();
        return exitstatus;
}


int
exitcmd(int argc, char **argv)
{
        if (stoppedjobs())
                return 0;
        if (argc > 1)
                exitshell(number(argv[1]));
        else
                exitshell_savedstatus();
}