/*      $NetBSD: lex.c,v 1.47 2024/08/17 19:18:10 andvar 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 <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)lex.c       8.2 (Berkeley) 4/20/95";
#else
__RCSID("$NetBSD: lex.c,v 1.47 2024/08/17 19:18:10 andvar Exp $");
#endif
#endif /* not lint */

#include <assert.h>
#include <util.h>

#include "rcv.h"
#include "extern.h"
#ifdef USE_EDITLINE
#include "complete.h"
#endif
#include "format.h"
#include "sig.h"
#include "thread.h"

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

static const char *prompt = DEFAULT_PROMPT;
static int      *msgvec;
static int      inithdr;                /* Am printing startup headers. */
static jmp_buf  jmpbuf;                 /* The reset jmpbuf */
static int      reset_on_stop;          /* To do job control longjmp. */

#ifdef DEBUG_FILE_LEAK
struct glue {
        struct  glue *next;
        int     niobs;
        FILE    *iobs;
};
extern struct glue __sglue;

static int open_fd_cnt;
static int open_fp_cnt;

static int
file_count(void)
{
        struct glue *gp;
        FILE *fp;
        int n;
        int cnt;

        cnt = 0;
        for (gp = &__sglue; gp; gp = gp->next) {
                for (fp = gp->iobs, n = gp->niobs; --n >= 0; fp++)
                        if (fp->_flags)
                                cnt++;
        }
        return cnt;
}

static int
fds_count(void)
{
        int maxfd;
        int cnt;
        int fd;

        maxfd = fcntl(0, F_MAXFD);
        if (maxfd == -1) {
                warn("fcntl");
                return -1;
        }

        cnt = 0;
        for (fd = 0; fd <= maxfd; fd++) {
                struct stat sb;

                if (fstat(fd, &sb) != -1)
                        cnt++;
                else if (errno != EBADF
#ifdef BROKEN_CLONE_STAT /* see PRs 37878 and 37550 */
                    && errno != EOPNOTSUPP
#endif
                        )
                        warn("fstat(%d): errno=%d", fd, errno);
        }
        return cnt;
}

static void
file_leak_init(void)
{
        open_fd_cnt = fds_count();
        open_fp_cnt = file_count();
}

static void
file_leak_check(void)
{
        if (open_fp_cnt != file_count() ||
            open_fd_cnt != fds_count()) {
                (void)printf("FILE LEAK WARNING: "
                    "fp-count: %d (%d)  "
                    "fd-count: %d (%d)  max-fd: %d\n",
                    file_count(), open_fp_cnt,
                    fds_count(), open_fd_cnt,
                    fcntl(0, F_MAXFD));
        }
}
#endif /* DEBUG_FILE_LEAK */

static void
update_mailname(const char *name)
{
        char tbuf[PATHSIZE];
        size_t l;

        /* Don't realpath(3) if it's only an update request */
        if (name != NULL && realpath(name, mailname) == NULL) {
                warn("Can't canonicalize `%s'", name);
                return;
        }

        if (getfold(tbuf, sizeof(tbuf)) >= 0) {
                l = strlen(tbuf);
                if (l < sizeof(tbuf) - 1)
                        tbuf[l++] = '/';
                if (strncmp(tbuf, mailname, l) == 0) {
                        char const *sep = "", *cp = mailname + l;

                        l = strlen(cp);
                        if (l >= sizeof(displayname)) {
                                cp += l;
                                cp -= sizeof(displayname) - 5;
                                sep = "...";
                        }
                        (void)snprintf(displayname, sizeof(displayname),
                            "+%s%.*s", sep,
                            (int)(sizeof(displayname) - 1 - strlen(sep)), cp);
                        return;
                }
        }

        l = strlen(mailname);
        if (l < sizeof(displayname))
                strcpy(displayname, mailname);
        else {
                l -= sizeof(displayname) - 4 - sizeof(displayname) / 3;
                (void)snprintf(displayname, sizeof(displayname), "%.*s...%s",
                        (int)sizeof(displayname) / 3, mailname, mailname + l);
        }
}

/*
 * Set the size of the message vector used to construct argument
 * lists to message list functions.
 */
static void
setmsize(int sz)
{
        if (msgvec != 0)
                free(msgvec);
        msgvec = ecalloc((size_t) (sz + 1), sizeof(*msgvec));
}

/*
 * 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
 * significance for mbox and so forth.
 */
PUBLIC int
setfile(const char *name)
{
        FILE *ibuf;
        int i, fd;
        struct stat stb;
        char isedit = *name != '%' || getuserid(myname) != (int)getuid();
        const char *who = name[1] ? name + 1 : myname;
        static int shudclob;
        char tempname[PATHSIZE];

        if ((name = expand(name)) == NULL)
                return -1;

        if ((ibuf = Fopen(name, "ref")) == NULL) {
                if (!isedit && errno == ENOENT)
                        goto nomail;
                warn("Can't open `%s'", name);
                return -1;
        }

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

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

        case S_IFREG:
                break;

        default:
                (void)Fclose(ibuf);
                errno = 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.
         */

        sig_check();
        sig_hold();
        if (shudclob)
                quit(jmpbuf);

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

        readonly = 0;
        if ((i = open(name, O_WRONLY)) < 0)
                readonly++;
        else
                (void)close(i);
        if (shudclob) {
                (void)fclose(itf);
                (void)fclose(otf);
        }
        shudclob = 1;
        edit = isedit;
        (void)strcpy(prevfile, mailname);
        update_mailname(name != mailname ? name : NULL);
        mailsize = fsize(ibuf);
        (void)snprintf(tempname, sizeof(tempname),
            "%s/mail.RxXXXXXXXXXX", tmpdir);
        if ((fd = mkstemp(tempname)) == -1 ||
            (otf = fdopen(fd, "wef")) == NULL)
                err(EXIT_FAILURE, "Can't create tmp file `%s'", tempname);
        if ((itf = fopen(tempname, "ref")) == NULL)
                err(EXIT_FAILURE, "Can't create tmp file `%s'", tempname);
        (void)rm(tempname);
        setptr(ibuf, (off_t)0);
        setmsize(get_abs_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);
        sig_release();
        sig_check();
        sawcom = 0;
        if (!edit && get_abs_msgCount() == 0) {
nomail:
                (void)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.
 */
PUBLIC int
incfile(void)
{
        off_t newsize;
        int omsgCount;
        FILE *ibuf;
        int rval;

        omsgCount = get_abs_msgCount();

        ibuf = Fopen(mailname, "ref");
        if (ibuf == NULL)
                return -1;
        sig_check();
        sig_hold();
        newsize = fsize(ibuf);
        if (newsize == 0 ||             /* mail box is now empty??? */
            newsize < mailsize) {       /* mail box has shrunk??? */
                rval = -1;
                goto done;
        }
        if (newsize == mailsize) {
                rval = 0;               /* no new mail */
                goto done;
        }
        setptr(ibuf, mailsize);         /* read in new mail */
        setmsize(get_abs_msgCount());   /* get the new message count */
        mailsize = ftell(ibuf);
        rval = get_abs_msgCount() - omsgCount;
 done:
        (void)Fclose(ibuf);
        sig_release();
        sig_check();
        return rval;
}

/*
 * Return a pointer to the comment character, respecting quoting as
 * done in getrawlist().  The comment character is ignored inside
 * quotes.
 */
static char *
comment_char(char *line)
{
        char *p;
        char quotec;
        quotec = '\0';
        for (p = line; *p; p++) {
                if (quotec != '\0') {
                        if (*p == quotec)
                                quotec = '\0';
                }
                else if (*p == '"' || *p == '\'')
                        quotec = *p;
                else if (*p == COMMENT_CHAR)
                        return p;
        }
        return NULL;
}

/*
 * Signal handler is hooked by setup_piping().
 * Respond to a broken pipe signal --
 * probably caused by quitting more.
 */
static jmp_buf  pipestop;

/*ARGSUSED*/
__dead static void
lex_brokpipe(int signo)
{

        longjmp(pipestop, signo);
}

/*
 * Check the command line for any requested piping or redirection,
 * depending on the value of 'c'.  If "enable-pipes" is set, search
 * the command line (cp) for the first occurrence of the character 'c'
 * that is not in a quote or (parenthese) group.
 */
PUBLIC char *
shellpr(char *cp)
{
        int quotec;
        int level;

        if (cp == NULL || value(ENAME_ENABLE_PIPES) == NULL)
                return NULL;

        level = 0;
        quotec = 0;
        for (/*EMPTY*/; *cp != '\0'; cp++) {
                if (quotec) {
                        if (*cp == quotec)
                                quotec = 0;
                        if (*cp == '\\' &&
                            (cp[1] == quotec || cp[1] == '\\'))
                                cp++;
                }
                else {
                        switch (*cp) {
                        case '|':
                        case '>':
                                if (level == 0)
                                        return cp;
                                break;
                        case '(':
                                level++;
                                break;
                        case ')':
                                level--;
                                break;
                        case '"':
                        case '\'':
                                quotec = *cp;
                                break;
                        default:
                                break;
                        }
                }
        }
        return NULL;
}

static int
do_paging(const char *cmd, int c_pipe)
{
        char *cp, *p;

        if (value(ENAME_PAGER_OFF) != NULL)
                return 0;

        if (c_pipe & C_PIPE_PAGER)
                return 1;

        if (c_pipe & C_PIPE_CRT && value(ENAME_CRT) != NULL)
                return 1;

        if ((cp = value(ENAME_PAGE_ALSO)) == NULL)
                return 0;

        if ((p = strcasestr(cp, cmd)) == NULL)
                return 0;

        if (p != cp && p[-1] != ',' && !is_WSP(p[-1]))
                return 0;

        p += strlen(cmd);

        return (*p == '\0' || *p == ',' || is_WSP(*p));
}

/*
 * Setup any pipe or redirection that the command line indicates.
 * If none, then setup the pager unless "pager-off" is defined.
 */
static FILE *fp_stop = NULL;
static int oldfd1 = -1;
static sig_t old_sigpipe;

static int
setup_piping(const char *cmd, char *cmdline, int c_pipe)
{
        FILE *fout;
        FILE *last_file;
        char *cp;

        sig_check();

        last_file = last_registered_file(0);

        fout = NULL;
        if ((cp = shellpr(cmdline)) != NULL) {
                char c;
                c = *cp;
                *cp = '\0';
                cp++;

                if (c == '|') {
                        if ((fout = Popen(cp, "we")) == NULL) {
                                warn("Popen: %s", cp);
                                return -1;
                        }
                }
                else {
                        const char *mode;
                        assert(c == '>');
                        mode = *cp == '>' ? "ae" : "we";
                        if (*cp == '>')
                                cp++;

                        cp = skip_WSP(cp);
                        if ((fout = Fopen(cp, mode)) == NULL) {
                                warn("Fopen: %s", cp);
                                return -1;
                        }
                }

        }
        else if (do_paging(cmd, c_pipe)) {
                const char *pager;
                pager = value(ENAME_PAGER);
                if (pager == NULL || *pager == '\0')
                        pager = _PATH_MORE;

                if ((fout = Popen(pager, "we")) == NULL) {
                        warn("Popen: %s", pager);
                        return -1;
                }
        }

        if (fout) {
                old_sigpipe = sig_signal(SIGPIPE, lex_brokpipe);
                (void)fflush(stdout);
                if ((oldfd1 = dup(STDOUT_FILENO)) == -1)
                        err(EXIT_FAILURE, "dup failed");
                if (dup2(fileno(fout), STDOUT_FILENO) == -1)
                        err(EXIT_FAILURE, "dup2 failed");
                fp_stop = last_file;
        }
        return 0;
}

/*
 * This will close any piping started by setup_piping().
 */
static void
close_piping(void)
{
        sigset_t oset;
        struct sigaction osa;

        if (oldfd1 != -1) {
                (void)fflush(stdout);
                if (fileno(stdout) != oldfd1 &&
                    dup2(oldfd1, STDOUT_FILENO) == -1)
                        err(EXIT_FAILURE, "dup2 failed");

                (void)sig_ignore(SIGPIPE, &osa, &oset);

                close_top_files(fp_stop);
                fp_stop = NULL;
                (void)close(oldfd1);
                oldfd1 = -1;

                (void)sig_signal(SIGPIPE, old_sigpipe);
                (void)sig_restore(SIGPIPE, &osa, &oset);
        }
        sig_check();
}

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

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

/*
 * Find the correct command in the command table corresponding
 * to the passed command "word"
 */
PUBLIC const struct cmd *
lex(char word[])
{
        const struct cmd *cp;

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

PUBLIC char *
get_cmdname(char *buf)
{
        char *cp;
        char *cmd;
        size_t len;

        for (cp = buf; *cp; cp++)
                if (strchr(" \t0123456789$^.:/-+*'\">|", *cp) != NULL)
                        break;
        /* XXX - Don't miss the pipe command! */
        if (cp == buf && *cp == '|')
                cp++;
        len = cp - buf + 1;
        cmd = salloc(len);
        (void)strlcpy(cmd, buf, len);
        return cmd;
}

/*
 * 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.
 * execute_contxt_e is in extern.h.
 */
PUBLIC int
execute(char linebuf[], enum execute_contxt_e contxt)
{
        char *word;
        char *arglist[MAXARGC];
        const struct cmd * volatile com = NULL;
        char *volatile cp;
        int retval;
        int c;
        volatile 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.
         */

        cp = skip_space(linebuf);
        if (*cp == '!') {
                if (sourcing) {
                        (void)printf("Can't \"!\" while sourcing\n");
                        goto out;
                }
                (void)shell(cp + 1);
                return 0;
        }

        word = get_cmdname(cp);
        cp += strlen(word);

        /*
         * 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) {
                (void)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 && (cond & CSKIP))
                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 (mailmode == mm_sending && (com->c_argtype & M) == 0) {
                (void)printf("May not execute \"%s\" while sending\n",
                    com->c_name);
                goto out;
        }
        if (sourcing && com->c_argtype & I) {
                (void)printf("May not execute \"%s\" while sourcing\n",
                    com->c_name);
                goto out;
        }
        if (readonly && com->c_argtype & W) {
                (void)printf("May not execute \"%s\" -- message file is read only\n",
                   com->c_name);
                goto out;
        }
        if (contxt == ec_composing && com->c_argtype & R) {
                (void)printf("Cannot recursively invoke \"%s\"\n", com->c_name);
                goto out;
        }

        if (!sourcing && com->c_pipe && value(ENAME_INTERACTIVE) != NULL) {

                sig_check();
                if (setjmp(pipestop))
                        goto out;

                if (setup_piping(com->c_name, cp, com->c_pipe) == -1)
                        goto out;
        }
        switch (com->c_argtype & ARGTYPE_MASK) {
        case MSGLIST:
                /*
                 * A message list defaulting to nearest forward
                 * legal message.
                 */
                if (msgvec == 0) {
                        (void)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) {
                        (void)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) {
                        (void)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.
                 */
                cp = skip_space(cp);
                e = (*com->c_func)(cp);
                break;

        case RAWLIST:
                /*
                 * A vector of strings, in shell style.
                 */
                if ((c = getrawlist(cp, arglist, (int)__arraycount(arglist))) < 0)
                        break;
                if (c < com->c_minargs) {
                        (void)printf("%s requires at least %d arg(s)\n",
                                com->c_name, com->c_minargs);
                        break;
                }
                if (c > com->c_maxargs) {
                        (void)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(EXIT_FAILURE, "Unknown argtype");
        }

out:
        close_piping();

        /*
         * Exit the current source file on
         * error.
         */
        retval = 0;
        if (e) {
                if (e < 0)
                        retval = 1;
                else if (loading)
                        retval = 1;
                else if (sourcing)
                        (void)unstack();
        }
        else if (com != NULL) {
                if (contxt != ec_autoprint && com->c_argtype & P &&
                    value(ENAME_AUTOPRINT) != NULL &&
                    (dot->m_flag & MDELETED) == 0)
                        (void)execute(__UNCONST("print ."), ec_autoprint);
                if (!sourcing && (com->c_argtype & T) == 0)
                        sawcom = 1;
        }
        sig_check();
        return retval;
}

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

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

        close_piping();
        close_all_files();

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

/*
 * Branch here on hangup signal and simulate "exit".
 */
/*ARGSUSED*/
__dead static void
lex_hangup(int s __unused)
{

        /* nothing to do? */
        exit(EXIT_FAILURE);
}

/*
 * When we wake up after ^Z, reprint the prompt.
 *
 * NOTE: EditLine deals with the prompt and job control, so with it
 * this does nothing, i.e., reset_on_stop == 0.
 */
static void
lex_stop(int signo)
{

        if (reset_on_stop) {
                reset_on_stop = 0;
                longjmp(jmpbuf, signo);
        }
}

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

#ifdef DEBUG_FILE_LEAK
        file_leak_init();
#endif

        if (!sourcing) {
                sig_check();

                sig_hold();
                (void)sig_signal(SIGINT,  lex_intr);
                (void)sig_signal(SIGHUP,  lex_hangup);
                (void)sig_signal(SIGTSTP, lex_stop);
                (void)sig_signal(SIGTTOU, lex_stop);
                (void)sig_signal(SIGTTIN, lex_stop);
                sig_release();
        }

        (void)setjmp(jmpbuf);   /* "reset" location if we got an interrupt */

        eofloop = 0;    /* initialize this after a possible longjmp */
        for (;;) {
                sig_check();
                (void)fflush(stdout);
                sreset();
                /*
                 * Print the prompt, if needed.  Clear out
                 * string space, and flush the output.
                 */
                if (!sourcing && value(ENAME_INTERACTIVE) != NULL) {
                        if ((prompt = value(ENAME_PROMPT)) == NULL)
                                prompt = DEFAULT_PROMPT;
                        prompt = smsgprintf(prompt, dot);
                        if ((value(ENAME_AUTOINC) != NULL) && (incfile() > 0))
                                (void)printf("New mail has arrived.\n");

#ifndef USE_EDITLINE
                        reset_on_stop = 1;      /* enable job control longjmp */
                        (void)printf("%s", prompt);
#endif
                }
#ifdef DEBUG_FILE_LEAK
                file_leak_check();
#endif
                /*
                 * Read a line of commands from the current input
                 * and handle end of file specially.
                 */
                n = 0;
                for (;;) {
                        sig_check();
#ifdef USE_EDITLINE
                        if (!sourcing) {
                                char *line;

                                line = my_gets(&elm.command, prompt, NULL);
                                if (line == NULL) {
                                        if (n == 0)
                                                n = -1;
                                        break;
                                }
                                (void)strlcpy(linebuf, line, sizeof(linebuf));
                        }
                        else {
                                if (readline(input, &linebuf[n], LINESIZE - n, 0) < 0) {
                                        if (n == 0)
                                                n = -1;
                                        break;
                                }
                        }
#else /* USE_EDITLINE */
                        if (readline(input, &linebuf[n], LINESIZE - n, reset_on_stop) < 0) {
                                if (n == 0)
                                        n = -1;
                                break;
                        }
#endif /* USE_EDITLINE */
                        if (!sourcing)
                                setscreensize(); /* so we can resize window */

                        if (sourcing) {  /* allow comments in source files */
                                char *ptr;
                                if ((ptr = comment_char(linebuf)) != NULL)
                                        *ptr = '\0';
                        }
                        if ((n = (int)strlen(linebuf)) == 0)
                                break;
                        n--;
                        if (linebuf[n] != '\\')
                                break;
                        linebuf[n++] = ' ';
                }
#ifndef USE_EDITLINE
                sig_check();
                reset_on_stop = 0;      /* disable job control longjmp */
#endif
                if (n < 0) {
                        char *p;

                        /* eof */
                        if (loading)
                                break;
                        if (sourcing) {
                                (void)unstack();
                                continue;
                        }
                        if (value(ENAME_INTERACTIVE) != NULL &&
                            (p = value(ENAME_IGNOREEOF)) != NULL &&
                            ++eofloop < (*p == '\0' ? 25 : atoi(p))) {
                                (void)printf("Use \"quit\" to quit.\n");
                                continue;
                        }
                        break;
                }
                eofloop = 0;
                if (execute(linebuf, ec_normal))
                        break;
        }
}

/*
 * Announce information about the file we are editing.
 * Return a likely place to set dot.
 */
PUBLIC int
newfileinfo(int omsgCount)
{
        struct message *mp;
        int d, n, s, t, u, mdot;

        /*
         * Figure out where to set the 'dot'.  Use the first new or
         * unread message.
         */
        for (mp = get_abs_message(omsgCount + 1); mp;
             mp = next_abs_message(mp))
                if (mp->m_flag & MNEW)
                        break;

        if (mp == NULL)
                for (mp = get_abs_message(omsgCount + 1); mp;
                     mp = next_abs_message(mp))
                        if ((mp->m_flag & MREAD) == 0)
                                break;
        if (mp != NULL)
                mdot = get_msgnum(mp);
        else
                mdot = omsgCount + 1;
#ifdef THREAD_SUPPORT
        /*
         * See if the message is in the current thread.
         */
        if (mp != NULL && get_message(1) != NULL && get_message(mdot) != mp)
                mdot = 0;
#endif
        /*
         * Scan the message array counting the new, unread, deleted,
         * and saved messages.
         */
        d = n = s = t = u = 0;
        for (mp = get_abs_message(1); mp; mp = next_abs_message(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++;
                if (mp->m_flag & MTAGGED)
                        t++;
        }
        /*
         * Display the statistics.
         */
        update_mailname(NULL);
        (void)printf("\"%s\": ", displayname);
        {
                int cnt = get_abs_msgCount();
                (void)printf("%d message%s", cnt, cnt == 1 ? "" : "s");
        }
        if (n > 0)
                (void)printf(" %d new", n);
        if (u-n > 0)
                (void)printf(" %d unread", u);
        if (t > 0)
                (void)printf(" %d tagged", t);
        if (d > 0)
                (void)printf(" %d deleted", d);
        if (s > 0)
                (void)printf(" %d saved", s);
        if (readonly)
                (void)printf(" [Read only]");
        (void)printf("\n");

        return mdot;
}

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

        mdot = newfileinfo(0);
        vec[0] = mdot;
        vec[1] = 0;
        if ((dot = get_message(mdot)) == NULL)
                dot = get_abs_message(1); /* make sure we get something! */
        if (get_abs_msgCount() > 0 && value(ENAME_NOHEADER) == NULL) {
                inithdr++;
                (void)headers(vec);
                inithdr = 0;
        }
}

/*
 * Print the current version number.
 */

/*ARGSUSED*/
PUBLIC int
pversion(void *v __unused)
{
        (void)printf("Version %s\n", version);
        return 0;
}

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

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