/*      $OpenBSD: lex.c,v 1.43 2023/03/08 04:43:11 guenther Exp $       */
/*      $NetBSD: lex.c,v 1.10 1997/05/17 19:55:13 pk Exp $      */

/*
 * 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.
 */

char    *prompt = "& ";

const struct cmd *com;  /* command we are running */

/*
 * 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.
 */
int
setfile(char *name)
{
        FILE *ibuf;
        int i, fd;
        struct stat stb;
        char isedit = *name != '%';
        const char *who = name[1] ? name + 1 : myname;
        char tempname[PATHSIZE];
        static int shudclob;

        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) == -1) {
                warn("fstat");
                (void)Fclose(ibuf);
                return(-1);
        }

        switch (stb.st_mode & S_IFMT) {
        case S_IFDIR:
                (void)Fclose(ibuf);
                warnc(EISDIR, "%s", name);
                return(-1);

        case S_IFREG:
                break;

        default:
                (void)Fclose(ibuf);
                warnc(EINVAL, "%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, O_WRONLY)) == -1)
                readonly++;
        else
                (void)close(i);
        if (shudclob) {
                (void)fclose(itf);
                (void)fclose(otf);
        }
        shudclob = 1;
        edit = isedit;
        strlcpy(prevfile, mailname, PATHSIZE);
        if (name != mailname)
                strlcpy(mailname, name, sizeof(mailname));
        mailsize = fsize(ibuf);
        (void)snprintf(tempname, sizeof(tempname),
            "%s/mail.RxXXXXXXXXXX", tmpdir);
        if ((fd = mkostemp(tempname, O_CLOEXEC)) == -1 ||
            (otf = fdopen(fd, "w")) == NULL)
                err(1, "%s", tempname);
        if ((itf = fopen(tempname, "re")) == NULL)
                err(1, "%s", tempname);
        (void)rm(tempname);
        setptr(ibuf, (off_t)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 = ftell(ibuf);
        (void)Fclose(ibuf);
        relsesigs();
        sawcom = 0;
        if (!edit && msgCount == 0) {
nomail:
                fprintf(stderr, "No mail for %s\n", who);
                return(-1);
        }
        return(0);
}

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

        ibuf = Fopen(mailname, "r");
        if (ibuf == NULL)
                return(-1);
        holdsigs();
        if (!spool_lock()) {
                (void)Fclose(ibuf);
                relsesigs();
                return(-1);
        }
        newsize = fsize(ibuf);
        /* make sure mail box has grown and is non-empty */
        if (newsize == 0 || newsize <= mailsize) {
                (void)Fclose(ibuf);
                spool_unlock();
                relsesigs();
                return(newsize == mailsize ? 0 : -1);
        }
        setptr(ibuf, mailsize);
        setmsize(msgCount);
        mailsize = ftell(ibuf);
        (void)Fclose(ibuf);
        spool_unlock();
        relsesigs();
        return(msgCount - omsgCount);
}


int     *msgvec;
int     reset_on_stop;                  /* reset prompt if stopped */

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

        prompt:
        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))
                                puts("New mail has arrived.");
                        reset_on_stop = 1;
                        printf("%s", prompt);
                }
                fflush(stdout);
                sreset();
                /*
                 * Read a line of commands from the current input
                 * and handle end of file specially.
                 */
                n = 0;
                sig = 0;
                sigp = sourcing ? NULL : &sig;
                for (;;) {
                        if (readline(input, &linebuf[n], LINESIZE - n, sigp) < 0) {
                                if (sig) {
                                        if (sig == SIGINT)
                                                dointr();
                                        else if (sig == SIGHUP)
                                                /* nothing to do? */
                                                exit(1);
                                        else {
                                                /* Stopped by job control */
                                                (void)kill(0, sig);
                                                if (reset_on_stop)
                                                        reset_on_stop = 0;
                                        }
                                        goto prompt;
                                }
                                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) {
                                puts("Use \"quit\" to quit.");
                                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];
        char *cp, *cp2;
        int c, muvec[2];
        int e = 1;

        com = NULL;

        /*
         * 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) {
                        puts("Can't \"!\" while sourcing");
                        goto out;
                }
                shell(cp+1);
                return(0);
        }
        cp2 = word;
        while (*cp &&
                strchr(" \t0123456789$^.:/-+*'\"", (unsigned char)*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|STRLIST:
                /*
                 * A message list defaulting to nearest forward
                 * legal message.
                 */
                if (msgvec == 0) {
                        puts("Illegal use of \"message list\"");
                        break;
                }
                /*
                 * remove leading blanks.
                 */
                while (isspace((unsigned char)*cp))
                        cp++;

                if (isdigit((unsigned char)*cp) || *cp == ':') {
                        if ((c = getmsglist(cp, msgvec, com->c_msgflag)) < 0)
                                break;
                        /* position to next space - past the message list */
                        while (!isspace((unsigned char)*cp))
                                cp++;
                        /* position to next non-space */
                        while (isspace((unsigned char)*cp))
                                cp++;
                } else {
                        c = 0; /* no message list */
                }

                if (c  == 0) {
                        *msgvec = first(com->c_msgflag,
                                com->c_msgmask);
                        msgvec[1] = 0;
                }
                if (*msgvec == 0) {
                        puts("No applicable messages");
                        break;
                }
                /*
                 * Just the straight string, with
                 * leading blanks removed.
                 */
                while (isspace((unsigned char)*cp))
                        cp++;

                e = (*com->c_func2)(msgvec, cp);
                break;

        case MSGLIST:
                /*
                 * A message list defaulting to nearest forward
                 * legal message.
                 */
                if (msgvec == NULL) {
                        puts("Illegal use of \"message list\"");
                        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) {
                        puts("No applicable messages");
                        break;
                }
                e = (*com->c_func)(msgvec);
                break;

        case NDMLIST:
                /*
                 * A message list with no defaults, but no error
                 * if none exist.
                 */
                if (msgvec == 0) {
                        puts("Illegal use of \"message list\"");
                        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 n)
{
        int *msgvec2;
        size_t msize;

        msize = (n + 1) * sizeof(*msgvec);
        if ((msgvec2 = realloc(msgvec, msize)) == NULL)
                err(1, "realloc");
        msgvec = msgvec2;
        memset(msgvec, 0, msize);
}

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

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

        if (word[0] == '#')
                word = "#";
        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(char *as1, char *as2)
{
        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.
 */
int     inithdr;                        /* am printing startup headers */

void
dointr(void)
{

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

        close_all_files();

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

/*
 * 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], zname[PATHSIZE], *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)) >= 0) {
                strlcat(fname, "/", sizeof(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)
                fputs("1 message", stdout);
        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)
                fputs(" [Read only]", stdout);
        putchar('\n');
        return(mdot);
}

/*
 * Print the current version number.
 */
int
pversion(void *v)
{
        extern const char version[];

        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);
}