/*-
 * 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 <signal.h>
#include <unistd.h>
#include <stdlib.h>

#include "shell.h"
#define DEFINE_OPTIONS
#include "options.h"
#undef DEFINE_OPTIONS
#include "nodes.h"      /* for other header files */
#include "eval.h"
#include "jobs.h"
#include "input.h"
#include "output.h"
#include "trap.h"
#include "var.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "builtins.h"
#ifndef NO_HISTORY
#include "myhistedit.h"
#endif

char *arg0;                     /* value of $0 */
struct shparam shellparam;      /* current positional parameters */
char **argptr;                  /* argument list for builtin commands */
char *shoptarg;                 /* set by nextopt (like getopt) */
char *nextopt_optptr;           /* used by nextopt */

char *minusc;                   /* argument to -c option */


static int options(int);
static void minus_o(char *, int);
static void setoption(int, int);
static void setoptionbyindex(int, int);
static void setparam(int, char **);
static int getopts(char *, char *, char **, char ***, char **);


/*
 * Process the shell command line arguments.
 */

int
procargs(int argc, char **argv)
{
        int i, login;
        char *scriptname;

        argptr = argv;
        login = argptr[0] != NULL && argptr[0][0] == '-';
        if (argc > 0)
                argptr++;
        for (i = 0; i < NOPTS; i++)
                optval[i] = 2;
        privileged = (getuid() != geteuid() || getgid() != getegid());
        login |= options(1);
        if (*argptr == NULL && minusc == NULL)
                sflag = 1;
        if (iflag != 0 && sflag == 1 && isatty(0) && isatty(1)) {
                iflag = 1;
                if (Eflag == 2)
                        Eflag = 1;
        }
        if (mflag == 2)
                mflag = iflag;
        for (i = 0; i < NOPTS; i++)
                if (optval[i] == 2)
                        optval[i] = 0;
        arg0 = argv[0];
        if (sflag == 0 && minusc == NULL) {
                scriptname = *argptr++;
                setinputfile(scriptname, 0, -1 /* verify */);
                commandname = arg0 = scriptname;
        }
        /* POSIX 1003.2: first arg after -c cmd is $0, remainder $1... */
        if (argptr && minusc && *argptr)
                arg0 = *argptr++;

        shellparam.p = argptr;
        shellparam.reset = 1;
        /* assert(shellparam.malloc == 0 && shellparam.nparam == 0); */
        while (*argptr) {
                shellparam.nparam++;
                argptr++;
        }
        optschanged();

        return (login);
}


void
optschanged(void)
{
        setinteractive();
#ifndef NO_HISTORY
        histedit();
#endif
        setjobctl(mflag);
}

/*
 * Process shell options.  The global variable argptr contains a pointer
 * to the argument list; we advance it past the options.
 * If cmdline is true, process the shell's argv; otherwise, process arguments
 * to the set special builtin.
 */

static int
options(int cmdline)
{
        char *kp, *p;
        int val;
        int c;
        int login = 0;

        if (cmdline)
                minusc = NULL;
        while ((p = *argptr) != NULL) {
                argptr++;
                if ((c = *p++) == '-') {
                        val = 1;
                        /* A "-" or  "--" terminates options */
                        if (p[0] == '\0')
                                goto end_options1;
                        if (p[0] == '-' && p[1] == '\0')
                                goto end_options2;
                        /**
                         * For the benefit of `#!' lines in shell scripts,
                         * treat a string of '-- *#.*' the same as '--'.
                         * This is needed so that a script starting with:
                         *      #!/bin/sh -- # -*- perl -*-
                         * will continue to work after a change is made to
                         * kern/imgact_shell.c to NOT token-ize the options
                         * specified on a '#!' line.  A bit of a kludge,
                         * but that trick is recommended in documentation
                         * for some scripting languages, and we might as
                         * well continue to support it.
                         */
                        if (p[0] == '-') {
                                kp = p + 1;
                                while (*kp == ' ' || *kp == '\t')
                                        kp++;
                                if (*kp == '#' || *kp == '\0')
                                        goto end_options2;
                        }
                } else if (c == '+') {
                        val = 0;
                } else {
                        argptr--;
                        break;
                }
                while ((c = *p++) != '\0') {
                        if (c == 'c' && cmdline) {
                                char *q;

                                q = *argptr++;
                                if (q == NULL || minusc != NULL)
                                        error("Bad -c option");
                                minusc = q;
                        } else if (c == 'l' && cmdline) {
                                login = 1;
                        } else if (c == 'o') {
                                minus_o(*argptr, val);
                                if (*argptr)
                                        argptr++;
                        } else
                                setoption(c, val);
                }
        }
        return (login);

        /* When processing `set', a single "-" means turn off -x and -v */
end_options1:
        if (!cmdline) {
                xflag = vflag = 0;
                return (login);
        }

        /*
         * When processing `set', a "--" means the remaining arguments
         * replace the positional parameters in the active shell.  If
         * there are no remaining options, then all the positional
         * parameters are cleared (equivalent to doing ``shift $#'').
         */
end_options2:
        if (!cmdline) {
                if (*argptr == NULL)
                        setparam(0, argptr);
                return (login);
        }

        /*
         * At this point we are processing options given to 'sh' on a command
         * line.  If an end-of-options marker ("-" or "--") is followed by an
         * arg of "#", then skip over all remaining arguments.  Some scripting
         * languages (e.g.: perl) document that /bin/sh will implement this
         * behavior, and they recommend that users take advantage of it to
         * solve certain issues that can come up when writing a perl script.
         * Yes, this feature is in /bin/sh to help users write perl scripts.
         */
        p = *argptr;
        if (p != NULL && p[0] == '#' && p[1] == '\0') {
                while (*argptr != NULL)
                        argptr++;
                /* We need to keep the final argument */
                argptr--;
        }

        return (login);
}

static void
minus_o(char *name, int val)
{
        int i;
        const unsigned char *on;
        size_t len;

        if (name == NULL) {
                if (val) {
                        /* "Pretty" output. */
                        out1str("Current option settings\n");
                        for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
                                out1fmt("%-16.*s%s\n", *on, on + 1,
                                        optval[i] ? "on" : "off");
                } else {
                        /* Output suitable for re-input to shell. */
                        for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
                                out1fmt("%s %co %.*s%s",
                                    i % 6 == 0 ? "set" : "",
                                    optval[i] ? '-' : '+',
                                    *on, on + 1,
                                    i % 6 == 5 || i == NOPTS - 1 ? "\n" : "");
                }
        } else {
                len = strlen(name);
                for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
                        if (*on == len && memcmp(on + 1, name, len) == 0) {
                                setoptionbyindex(i, val);
                                return;
                        }
                error("Illegal option -o %s", name);
        }
}


static void
setoptionbyindex(int idx, int val)
{
        if (&optval[idx] == &privileged && !val && privileged) {
                if (setgid(getgid()) == -1)
                        error("setgid");
                if (setuid(getuid()) == -1)
                        error("setuid");
        }
        optval[idx] = val;
        if (val) {
                /* #%$ hack for ksh semantics */
                if (&optval[idx] == &Vflag)
                        Eflag = 0;
                else if (&optval[idx] == &Eflag)
                        Vflag = 0;
        }
}

static void
setoption(int flag, int val)
{
        int i;

        for (i = 0; i < NSHORTOPTS; i++)
                if (optletter[i] == flag) {
                        setoptionbyindex(i, val);
                        return;
                }
        error("Illegal option -%c", flag);
}


/*
 * Set the shell parameters.
 */

static void
setparam(int argc, char **argv)
{
        char **newparam;
        char **ap;

        ap = newparam = ckmalloc((argc + 1) * sizeof *ap);
        while (*argv) {
                *ap++ = savestr(*argv++);
        }
        *ap = NULL;
        freeparam(&shellparam);
        shellparam.malloc = 1;
        shellparam.nparam = argc;
        shellparam.p = newparam;
        shellparam.optp = NULL;
        shellparam.reset = 1;
        shellparam.optnext = NULL;
}


/*
 * Free the list of positional parameters.
 */

void
freeparam(struct shparam *param)
{
        char **ap;

        if (param->malloc) {
                for (ap = param->p ; *ap ; ap++)
                        ckfree(*ap);
                ckfree(param->p);
        }
        if (param->optp) {
                for (ap = param->optp ; *ap ; ap++)
                        ckfree(*ap);
                ckfree(param->optp);
        }
}



/*
 * The shift builtin command.
 */

int
shiftcmd(int argc, char **argv)
{
        int i, n;

        n = 1;
        if (argc > 1)
                n = number(argv[1]);
        if (n > shellparam.nparam)
                return 1;
        INTOFF;
        shellparam.nparam -= n;
        if (shellparam.malloc)
                for (i = 0; i < n; i++)
                        ckfree(shellparam.p[i]);
        memmove(shellparam.p, shellparam.p + n,
            (shellparam.nparam + 1) * sizeof(shellparam.p[0]));
        shellparam.reset = 1;
        INTON;
        return 0;
}



/*
 * The set builtin command.
 */

int
setcmd(int argc, char **argv)
{
        if (argc == 1)
                return showvarscmd(argc, argv);
        INTOFF;
        options(0);
        optschanged();
        if (*argptr != NULL) {
                setparam(argc - (argptr - argv), argptr);
        }
        INTON;
        return 0;
}


void
getoptsreset(const char *value)
{
        while (*value == '0')
                value++;
        if (strcmp(value, "1") == 0)
                shellparam.reset = 1;
}

/*
 * The getopts builtin.  Shellparam.optnext points to the next argument
 * to be processed.  Shellparam.optptr points to the next character to
 * be processed in the current argument.  If shellparam.optnext is NULL,
 * then it's the first time getopts has been called.
 */

int
getoptscmd(int argc, char **argv)
{
        char **optbase = NULL, **ap;
        int i;

        if (argc < 3)
                error("usage: getopts optstring var [arg]");

        if (shellparam.reset == 1) {
                INTOFF;
                if (shellparam.optp) {
                        for (ap = shellparam.optp ; *ap ; ap++)
                                ckfree(*ap);
                        ckfree(shellparam.optp);
                        shellparam.optp = NULL;
                }
                if (argc > 3) {
                        shellparam.optp = ckmalloc((argc - 2) * sizeof *ap);
                        memset(shellparam.optp, '\0', (argc - 2) * sizeof *ap);
                        for (i = 0; i < argc - 3; i++)
                                shellparam.optp[i] = savestr(argv[i + 3]);
                }
                INTON;
                optbase = argc == 3 ? shellparam.p : shellparam.optp;
                shellparam.optnext = optbase;
                shellparam.optptr = NULL;
                shellparam.reset = 0;
        } else
                optbase = shellparam.optp ? shellparam.optp : shellparam.p;

        return getopts(argv[1], argv[2], optbase, &shellparam.optnext,
                       &shellparam.optptr);
}

static int
getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
    char **optptr)
{
        char *p, *q;
        char c = '?';
        int done = 0;
        int ind = 0;
        int err = 0;
        char s[10];
        const char *newoptarg = NULL;

        if ((p = *optptr) == NULL || *p == '\0') {
                /* Current word is done, advance */
                if (*optnext == NULL)
                        return 1;
                p = **optnext;
                if (p == NULL || *p != '-' || *++p == '\0') {
atend:
                        ind = *optnext - optfirst + 1;
                        *optnext = NULL;
                        p = NULL;
                        done = 1;
                        goto out;
                }
                (*optnext)++;
                if (p[0] == '-' && p[1] == '\0')        /* check for "--" */
                        goto atend;
        }

        c = *p++;
        for (q = optstr; *q != c; ) {
                if (*q == '\0') {
                        if (optstr[0] == ':') {
                                s[0] = c;
                                s[1] = '\0';
                                newoptarg = s;
                        }
                        else
                                out2fmt_flush("Illegal option -%c\n", c);
                        c = '?';
                        goto out;
                }
                if (*++q == ':')
                        q++;
        }

        if (*++q == ':') {
                if (*p == '\0' && (p = **optnext) == NULL) {
                        if (optstr[0] == ':') {
                                s[0] = c;
                                s[1] = '\0';
                                newoptarg = s;
                                c = ':';
                        }
                        else {
                                out2fmt_flush("No arg for -%c option\n", c);
                                c = '?';
                        }
                        goto out;
                }

                if (p == **optnext)
                        (*optnext)++;
                newoptarg = p;
                p = NULL;
        }

out:
        if (*optnext != NULL)
                ind = *optnext - optfirst + 1;
        *optptr = p;
        if (newoptarg != NULL)
                err |= setvarsafe("OPTARG", newoptarg, 0);
        else {
                INTOFF;
                err |= unsetvar("OPTARG");
                INTON;
        }
        fmtstr(s, sizeof(s), "%d", ind);
        err |= setvarsafe("OPTIND", s, VNOFUNC);
        s[0] = c;
        s[1] = '\0';
        err |= setvarsafe(optvar, s, 0);
        if (err) {
                *optnext = NULL;
                *optptr = NULL;
                flushall();
                exraise(EXERROR);
        }
        return done;
}

/*
 * Standard option processing (a la getopt) for builtin routines.  The
 * only argument that is passed to nextopt is the option string; the
 * other arguments are unnecessary.  It returns the option, or '\0' on
 * end of input.
 */

int
nextopt(const char *optstring)
{
        char *p;
        const char *q;
        char c;

        if ((p = nextopt_optptr) == NULL || *p == '\0') {
                p = *argptr;
                if (p == NULL || *p != '-' || *++p == '\0')
                        return '\0';
                argptr++;
                if (p[0] == '-' && p[1] == '\0')        /* check for "--" */
                        return '\0';
        }
        c = *p++;
        for (q = optstring ; *q != c ; ) {
                if (*q == '\0')
                        error("Illegal option -%c", c);
                if (*++q == ':')
                        q++;
        }
        if (*++q == ':') {
                if (*p == '\0' && (p = *argptr++) == NULL)
                        error("No arg for -%c option", c);
                shoptarg = p;
                p = NULL;
        }
        if (p != NULL && *p != '\0')
                nextopt_optptr = p;
        else
                nextopt_optptr = NULL;
        return c;
}