/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 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. 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 "rcv.h"
#include <errno.h>
#include <fcntl.h>
#include "extern.h"

/*
 * Mail -- a mail program
 *
 * Lexical processing of commands.
 */

static const char       *prompt = "& ";

extern const struct cmd cmdtab[];
extern const char *version;     

/*
 * Set up editing on the given file name.
 * If the first character of name is %, we are considered to be
 * editing the file, otherwise we are reading our mail which has
 * signficance for mbox and so forth.
 *
 * If the -e option is being passed to mail, this function has a
 * tri-state return code: -1 on error, 0 on no mail, 1 if there is
 * mail.
 */
int
setfile(char *name)
{
        FILE *ibuf;
        int checkmode, i, fd;
        struct stat stb;
        char isedit = *name != '%' || getuserid(myname) != getuid();
        char *who = name[1] ? name + 1 : myname;
        char tempname[PATHSIZE];
        static int shudclob;

        checkmode = value("checkmode") != NULL;
        if ((name = expand(name)) == NULL)
                return (-1);

        if ((ibuf = Fopen(name, "r")) == NULL) {
                if (!isedit && errno == ENOENT)
                        goto nomail;
                warn("%s", name);
                return (-1);
        }

        if (fstat(fileno(ibuf), &stb) < 0) {
                warn("fstat");
                (void)Fclose(ibuf);
                return (-1);
        }

        if (S_ISDIR(stb.st_mode) || !S_ISREG(stb.st_mode)) {
                (void)Fclose(ibuf);
                errno = S_ISDIR(stb.st_mode) ? EISDIR : EINVAL;
                warn("%s", name);
                return (-1);
        }

        /*
         * Looks like all will be well.  We must now relinquish our
         * hold on the current set of stuff.  Must hold signals
         * while we are reading the new file, else we will ruin
         * the message[] data structure.
         */

        holdsigs();
        if (shudclob)
                quit();

        /*
         * Copy the messages into /tmp
         * and set pointers.
         */

        readonly = 0;
        if ((i = open(name, 1)) < 0)
                readonly++;
        else
                (void)close(i);
        if (shudclob) {
                (void)fclose(itf);
                (void)fclose(otf);
        }
        shudclob = 1;
        edit = isedit;
        strlcpy(prevfile, mailname, sizeof(prevfile));
        if (name != mailname)
                strlcpy(mailname, name, sizeof(mailname));
        mailsize = fsize(ibuf);
        (void)snprintf(tempname, sizeof(tempname),
            "%s/mail.RxXXXXXXXXXX", tmpdir);
        if ((fd = mkstemp(tempname)) == -1 || (otf = fdopen(fd, "w")) == NULL)
                err(1, "%s", tempname);
        (void)fcntl(fileno(otf), F_SETFD, 1);
        if ((itf = fopen(tempname, "r")) == NULL)
                err(1, "%s", tempname);
        (void)fcntl(fileno(itf), F_SETFD, 1);
        (void)rm(tempname);
        setptr(ibuf, 0);
        setmsize(msgCount);
        /*
         * New mail may have arrived while we were reading
         * the mail file, so reset mailsize to be where
         * we really are in the file...
         */
        mailsize = ftello(ibuf);
        (void)Fclose(ibuf);
        relsesigs();
        sawcom = 0;

        if ((checkmode || !edit) && msgCount == 0) {
nomail:
                if (!checkmode) {
                        fprintf(stderr, "No mail for %s\n", who);
                        return (-1);
                } else
                        return (0);
        }
        return (checkmode ? 1 : 0);
}

/*
 * Incorporate any new mail that has arrived since we first
 * started reading mail.
 */
int
incfile(void)
{
        off_t newsize;
        int omsgCount = msgCount;
        FILE *ibuf;

        ibuf = Fopen(mailname, "r");
        if (ibuf == NULL)
                return (-1);
        holdsigs();
        newsize = fsize(ibuf);
        if (newsize == 0)
                return (-1);            /* mail box is now empty??? */
        if (newsize < mailsize)
                return (-1);            /* mail box has shrunk??? */
        if (newsize == mailsize)
                return (0);             /* no new mail */
        setptr(ibuf, mailsize);
        setmsize(msgCount);
        mailsize = ftello(ibuf);
        (void)Fclose(ibuf);
        relsesigs();
        return (msgCount - omsgCount);
}

static int      *msgvec;
static int      reset_on_stop;          /* do a reset() if stopped */

/*
 * Interpret user commands one by one.  If standard input is not a tty,
 * print no prompt.
 */
void
commands(void)
{
        int n, eofloop = 0;
        char linebuf[LINESIZE];

        if (!sourcing) {
                if (signal(SIGINT, SIG_IGN) != SIG_IGN)
                        (void)signal(SIGINT, intr);
                (void)signal(SIGTSTP, stop);
                (void)signal(SIGTTOU, stop);
                (void)signal(SIGTTIN, stop);
        }
        setexit();
        for (;;) {
                /*
                 * Print the prompt, if needed.  Clear out
                 * string space, and flush the output.
                 */
                if (!sourcing && value("interactive") != NULL) {
                        if ((value("autoinc") != NULL) && (incfile() > 0))
                                printf("New mail has arrived.\n");
                        reset_on_stop = 1;
                        printf("%s", prompt);
                }
                (void)fflush(stdout);
                sreset();
                /*
                 * Read a line of commands from the current input
                 * and handle end of file specially.
                 */
                n = 0;
                for (;;) {
                        if (readline(input, &linebuf[n],
                            sizeof(linebuf) - n) < 0) {
                                if (n == 0)
                                        n = -1;
                                break;
                        }
                        if ((n = strlen(linebuf)) == 0)
                                break;
                        n--;
                        if (linebuf[n] != '\\')
                                break;
                        linebuf[n++] = ' ';
                }
                reset_on_stop = 0;
                if (n < 0) {
                                /* eof */
                        if (loading)
                                break;
                        if (sourcing) {
                                unstack();
                                continue;
                        }
                        if (value("interactive") != NULL &&
                            value("ignoreeof") != NULL &&
                            ++eofloop < 25) {
                                printf("Use \"quit\" to quit.\n");
                                continue;
                        }
                        break;
                }
                eofloop = 0;
                if (execute(linebuf, 0))
                        break;
        }
}

/*
 * Execute a single command.
 * Command functions return 0 for success, 1 for error, and -1
 * for abort.  A 1 or -1 aborts a load or source.  A -1 aborts
 * the interactive command loop.
 * Contxt is non-zero if called while composing mail.
 */
int
execute(char linebuf[], int contxt)
{
        char word[LINESIZE];
        char *arglist[MAXARGC];
        const struct cmd *com;
        char *cp, *cp2;
        int c, muvec[2];
        int e = 1;

        /*
         * Strip the white space away from the beginning
         * of the command, then scan out a word, which
         * consists of anything except digits and white space.
         *
         * Handle ! escapes differently to get the correct
         * lexical conventions.
         */

        for (cp = linebuf; isspace((unsigned char)*cp); cp++)
                ;
        if (*cp == '!') {
                if (sourcing) {
                        printf("Can't \"!\" while sourcing\n");
                        goto out;
                }
                shell(cp+1);
                return (0);
        }
        cp2 = word;
        while (*cp != '\0' && strchr(" \t0123456789$^.:/-+*'\"", *cp) == NULL)
                *cp2++ = *cp++;
        *cp2 = '\0';

        /*
         * Look up the command; if not found, bitch.
         * Normally, a blank command would map to the
         * first command in the table; while sourcing,
         * however, we ignore blank lines to eliminate
         * confusion.
         */

        if (sourcing && *word == '\0')
                return (0);
        com = lex(word);
        if (com == NULL) {
                printf("Unknown command: \"%s\"\n", word);
                goto out;
        }

        /*
         * See if we should execute the command -- if a conditional
         * we always execute it, otherwise, check the state of cond.
         */

        if ((com->c_argtype & F) == 0)
                if ((cond == CRCV && !rcvmode) || (cond == CSEND && rcvmode))
                        return (0);

        /*
         * Process the arguments to the command, depending
         * on the type he expects.  Default to an error.
         * If we are sourcing an interactive command, it's
         * an error.
         */

        if (!rcvmode && (com->c_argtype & M) == 0) {
                printf("May not execute \"%s\" while sending\n",
                    com->c_name);
                goto out;
        }
        if (sourcing && com->c_argtype & I) {
                printf("May not execute \"%s\" while sourcing\n",
                    com->c_name);
                goto out;
        }
        if (readonly && com->c_argtype & W) {
                printf("May not execute \"%s\" -- message file is read only\n",
                   com->c_name);
                goto out;
        }
        if (contxt && com->c_argtype & R) {
                printf("Cannot recursively invoke \"%s\"\n", com->c_name);
                goto out;
        }
        switch (com->c_argtype & ~(F|P|I|M|T|W|R)) {
        case MSGLIST:
                /*
                 * A message list defaulting to nearest forward
                 * legal message.
                 */
                if (msgvec == 0) {
                        printf("Illegal use of \"message list\"\n");
                        break;
                }
                if ((c = getmsglist(cp, msgvec, com->c_msgflag)) < 0)
                        break;
                if (c  == 0) {
                        *msgvec = first(com->c_msgflag, com->c_msgmask);
                        msgvec[1] = 0;
                }
                if (*msgvec == 0) {
                        printf("No applicable messages\n");
                        break;
                }
                e = (*com->c_func)(msgvec);
                break;

        case NDMLIST:
                /*
                 * A message list with no defaults, but no error
                 * if none exist.
                 */
                if (msgvec == 0) {
                        printf("Illegal use of \"message list\"\n");
                        break;
                }
                if (getmsglist(cp, msgvec, com->c_msgflag) < 0)
                        break;
                e = (*com->c_func)(msgvec);
                break;

        case STRLIST:
                /*
                 * Just the straight string, with
                 * leading blanks removed.
                 */
                while (isspace((unsigned char)*cp))
                        cp++;
                e = (*com->c_func)(cp);
                break;

        case RAWLIST:
                /*
                 * A vector of strings, in shell style.
                 */
                if ((c = getrawlist(cp, arglist,
                    sizeof(arglist) / sizeof(*arglist))) < 0)
                        break;
                if (c < com->c_minargs) {
                        printf("%s requires at least %d arg(s)\n",
                            com->c_name, com->c_minargs);
                        break;
                }
                if (c > com->c_maxargs) {
                        printf("%s takes no more than %d arg(s)\n",
                            com->c_name, com->c_maxargs);
                        break;
                }
                e = (*com->c_func)(arglist);
                break;

        case NOLIST:
                /*
                 * Just the constant zero, for exiting,
                 * eg.
                 */
                e = (*com->c_func)(0);
                break;

        default:
                errx(1, "Unknown argtype");
        }

out:
        /*
         * Exit the current source file on
         * error.
         */
        if (e) {
                if (e < 0)
                        return (1);
                if (loading)
                        return (1);
                if (sourcing)
                        unstack();
                return (0);
        }
        if (com == NULL)
                return (0);
        if (value("autoprint") != NULL && com->c_argtype & P)
                if ((dot->m_flag & MDELETED) == 0) {
                        muvec[0] = dot - &message[0] + 1;
                        muvec[1] = 0;
                        type(muvec);
                }
        if (!sourcing && (com->c_argtype & T) == 0)
                sawcom = 1;
        return (0);
}

/*
 * Set the size of the message vector used to construct argument
 * lists to message list functions.
 */
void
setmsize(int sz)
{

        if (msgvec != NULL)
                (void)free(msgvec);
        msgvec = calloc((unsigned)(sz + 1), sizeof(*msgvec));
}

/*
 * Find the correct command in the command table corresponding
 * to the passed command "word"
 */

const struct cmd *
lex(char word[])
{
        const struct cmd *cp;

        /*
         * ignore trailing chars after `#'
         *
         * lines with beginning `#' are comments
         * spaces before `#' are ignored in execute()
         */

        if (*word == '#')
            *(word+1) = '\0';


        for (cp = &cmdtab[0]; cp->c_name != NULL; cp++)
                if (isprefix(word, cp->c_name))
                        return (cp);
        return (NULL);
}

/*
 * Determine if as1 is a valid prefix of as2.
 * Return true if yep.
 */
int
isprefix(const char *as1, const char *as2)
{
        const char *s1, *s2;

        s1 = as1;
        s2 = as2;
        while (*s1++ == *s2)
                if (*s2++ == '\0')
                        return (1);
        return (*--s1 == '\0');
}

/*
 * The following gets called on receipt of an interrupt.  This is
 * to abort printout of a command, mainly.
 * Dispatching here when command() is inactive crashes rcv.
 * Close all open files except 0, 1, 2, and the temporary.
 * Also, unstack all source files.
 */

static int      inithdr;                /* am printing startup headers */

void
intr(int s __unused)
{

        noreset = 0;
        if (!inithdr)
                sawcom++;
        inithdr = 0;
        while (sourcing)
                unstack();

        close_all_files();

        if (image >= 0) {
                (void)close(image);
                image = -1;
        }
        fprintf(stderr, "Interrupt\n");
        reset(0);
}

/*
 * When we wake up after ^Z, reprint the prompt.
 */
void
stop(int s)
{
        sig_t old_action = signal(s, SIG_DFL);
        sigset_t nset;

        (void)sigemptyset(&nset);
        (void)sigaddset(&nset, s);
        (void)sigprocmask(SIG_UNBLOCK, &nset, NULL);
        (void)kill(0, s);
        (void)sigprocmask(SIG_BLOCK, &nset, NULL);
        (void)signal(s, old_action);
        if (reset_on_stop) {
                reset_on_stop = 0;
                reset(0);
        }
}

/*
 * Announce the presence of the current Mail version,
 * give the message count, and print a header listing.
 */
void
announce(void)
{
        int vec[2], mdot;

        mdot = newfileinfo(0);
        vec[0] = mdot;
        vec[1] = 0;
        dot = &message[mdot - 1];
        if (msgCount > 0 && value("noheader") == NULL) {
                inithdr++;
                headers(vec);
                inithdr = 0;
        }
}

/*
 * Announce information about the file we are editing.
 * Return a likely place to set dot.
 */
int
newfileinfo(int omsgCount)
{
        struct message *mp;
        int u, n, mdot, d, s;
        char fname[PATHSIZE+1], zname[PATHSIZE+1], *ename;

        for (mp = &message[omsgCount]; mp < &message[msgCount]; mp++)
                if (mp->m_flag & MNEW)
                        break;
        if (mp >= &message[msgCount])
                for (mp = &message[omsgCount]; mp < &message[msgCount]; mp++)
                        if ((mp->m_flag & MREAD) == 0)
                                break;
        if (mp < &message[msgCount])
                mdot = mp - &message[0] + 1;
        else
                mdot = omsgCount + 1;
        s = d = 0;
        for (mp = &message[0], n = 0, u = 0; mp < &message[msgCount]; mp++) {
                if (mp->m_flag & MNEW)
                        n++;
                if ((mp->m_flag & MREAD) == 0)
                        u++;
                if (mp->m_flag & MDELETED)
                        d++;
                if (mp->m_flag & MSAVED)
                        s++;
        }
        ename = mailname;
        if (getfold(fname, sizeof(fname) - 1) >= 0) {
                strcat(fname, "/");
                if (strncmp(fname, mailname, strlen(fname)) == 0) {
                        (void)snprintf(zname, sizeof(zname), "+%s",
                            mailname + strlen(fname));
                        ename = zname;
                }
        }
        printf("\"%s\": ", ename);
        if (msgCount == 1)
                printf("1 message");
        else
                printf("%d messages", msgCount);
        if (n > 0)
                printf(" %d new", n);
        if (u-n > 0)
                printf(" %d unread", u);
        if (d > 0)
                printf(" %d deleted", d);
        if (s > 0)
                printf(" %d saved", s);
        if (readonly)
                printf(" [Read only]");
        printf("\n");
        return (mdot);
}

/*
 * Print the current version number.
 */

int
pversion(void *arg __unused)
{

        printf("Version %s\n", version);
        return (0);
}

/*
 * Load a file of user definitions.
 */
void
load(char *name)
{
        FILE *in, *oldin;

        if ((in = Fopen(name, "r")) == NULL)
                return;
        oldin = input;
        input = in;
        loading = 1;
        sourcing = 1;
        commands();
        loading = 0;
        sourcing = 0;
        input = oldin;
        (void)Fclose(in);
}