/*      $NetBSD: list.c,v 1.29 2021/12/07 21:37:37 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[] = "@(#)list.c      8.4 (Berkeley) 5/1/95";
#else
__RCSID("$NetBSD: list.c,v 1.29 2021/12/07 21:37:37 andvar Exp $");
#endif
#endif /* not lint */

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

#include "rcv.h"
#include "extern.h"
#include "format.h"
#include "thread.h"
#include "mime.h"

/*
 * Mail -- a mail program
 *
 * Message list handling.
 */

/*
 * Token values returned by the scanner used for argument lists.
 * Also, sizes of scanner-related things.
 */
enum token_e {
        TEOL,                   /* End of the command line */
        TNUMBER,                /* A message number or range of numbers */
        TDASH,                  /* A simple dash */
        TSTRING,                /* A string (possibly containing '-') */
        TDOT,                   /* A "." */
        TUP,                    /* An "^" */
        TDOLLAR,                /* A "$" */
        TSTAR,                  /* A "*" */
        TOPEN,                  /* An '(' */
        TCLOSE,                 /* A ')' */
        TPLUS,                  /* A '+' */
        TAND,                   /* A '&' */
        TOR,                    /* A '|' */
        TXOR,                   /* A logical '^' */
        TNOT,                   /* A '!' */
        TERROR                  /* A lexical error */
};

#define REGDEP          2               /* Maximum regret depth. */
#define STRINGLEN       1024            /* Maximum length of string token */

static int      lexnumber;              /* Number of TNUMBER from scan() */
static char     lexstring[STRINGLEN];   /* String from TSTRING, scan() */
static int      regretp;                /* Pointer to TOS of regret tokens */
static int      regretstack[REGDEP];    /* Stack of regretted tokens */
static char     *string_stack[REGDEP];  /* Stack of regretted strings */
static int      numberstack[REGDEP];    /* Stack of regretted numbers */

/*
 * Scan out the list of string arguments, shell style
 * for a RAWLIST.
 */
PUBLIC int
getrawlist(const char line[], char **argv, int argc)
{
        char c, *cp2, quotec;
        const char *cp;
        int argn;
        char linebuf[LINESIZE];

        argn = 0;
        cp = line;
        for (;;) {
                cp = skip_WSP(cp);
                if (*cp == '\0')
                        break;
                if (argn >= argc - 1) {
                        (void)printf(
                        "Too many elements in the list; excess discarded.\n");
                        break;
                }
                cp2 = linebuf;
                quotec = '\0';
                while ((c = *cp) != '\0') {
                        cp++;
                        if (quotec != '\0') {
                                if (c == quotec)
                                        quotec = '\0';
                                else if (quotec != '\'' && c == '\\')
                                        switch (c = *cp++) {
                                        case '\0':
                                                *cp2++ = '\\';
                                                cp--;
                                                break;
                                        case '0': case '1': case '2': case '3':
                                        case '4': case '5': case '6': case '7':
                                                c -= '0';
                                                if (*cp >= '0' && *cp <= '7')
                                                        c = c * 8 + *cp++ - '0';
                                                if (*cp >= '0' && *cp <= '7')
                                                        c = c * 8 + *cp++ - '0';
                                                *cp2++ = c;
                                                break;
                                        case 'b':
                                                *cp2++ = '\b';
                                                break;
                                        case 'f':
                                                *cp2++ = '\f';
                                                break;
                                        case 'n':
                                                *cp2++ = '\n';
                                                break;
                                        case 'r':
                                                *cp2++ = '\r';
                                                break;
                                        case 't':
                                                *cp2++ = '\t';
                                                break;
                                        case 'v':
                                                *cp2++ = '\v';
                                                break;
                                        default:
                                                *cp2++ = c;
                                        }
                                else if (c == '^') {
                                        c = *cp++;
                                        if (c == '?')
                                                *cp2++ = '\177';
                                        /* null doesn't show up anyway */
                                        else if ((c >= 'A' && c <= '_') ||
                                                 (c >= 'a' && c <= 'z'))
                                                *cp2++ = c & 037;
                                        else {
                                                *cp2++ = '^';
                                                cp--;
                                        }
                                } else
                                        *cp2++ = c;
                        } else if (c == '"' || c == '\'')
                                quotec = c;
                        else if (is_WSP(c))
                                break;
                        else
                                *cp2++ = c;
                }
                *cp2 = '\0';
                argv[argn++] = savestr(linebuf);
        }
        argv[argn] = NULL;
        return argn;
}

/*
 * Mark all messages that the user wanted from the command
 * line in the message structure.  Return 0 on success, -1
 * on error.
 */

/*
 * Bit values for colon modifiers.
 */
#define CMBOX           0x001           /* Unread messages */
#define CMDELETED       0x002           /* Deleted messages */
#define CMMODIFY        0x004           /* Unread messages */
#define CMNEW           0x008           /* New messages */
#define CMOLD           0x010           /* Old messages */
#define CMPRESERVE      0x020           /* Unread messages */
#define CMREAD          0x040           /* Read messages */
#define CMSAVED         0x080           /* Saved messages */
#define CMTAGGED        0x100           /* Tagged messages */
#define CMUNREAD        0x200           /* Unread messages */
#define CMNEGATE        0x400           /* Negate the match */
#define CMMASK          0x7ff           /* Mask the valid bits */

/*
 * The following table describes the letters which can follow
 * the colon and gives the corresponding modifier bit.
 */

static const struct coltab {
        char    co_char;                /* What to find past : */
        int     co_bit;                 /* Associated modifier bit */
        int     co_mask;                /* m_status bits to mask */
        int     co_equal;               /* ... must equal this */
} coltab[] = {
        { '!',          CMNEGATE,       0,              0 },
        { 'd',          CMDELETED,      MDELETED,       MDELETED },
        { 'e',          CMMODIFY,       MMODIFY,        MMODIFY },
        { 'm',          CMBOX,          MBOX,           MBOX },
        { 'n',          CMNEW,          MNEW,           MNEW },
        { 'o',          CMOLD,          MNEW,           0 },
        { 'p',          CMPRESERVE,     MPRESERVE,      MPRESERVE },
        { 'r',          CMREAD,         MREAD,          MREAD },
        { 's',          CMSAVED,        MSAVED,         MSAVED },
        { 't',          CMTAGGED,       MTAGGED,        MTAGGED },
        { 'u',          CMUNREAD,       MREAD|MNEW,     0 },
        { 0,            0,              0,              0 }
};

static  int     lastcolmod;

static int
ignore_message(int m_flag, int colmod)
{
        int ignore_msg;
        const struct coltab *colp;

        ignore_msg = !(colmod & CMNEGATE);
        colmod &= (~CMNEGATE & CMMASK);

        for (colp = &coltab[0]; colp->co_char; colp++)
                if (colp->co_bit & colmod &&
                    (m_flag & colp->co_mask) == colp->co_equal)
                                return !ignore_msg;
        return ignore_msg;
}

/*
 * Turn the character after a colon modifier into a bit
 * value.
 */
static int
evalcol(int col)
{
        const struct coltab *colp;

        if (col == 0)
                return lastcolmod;
        for (colp = &coltab[0]; colp->co_char; colp++)
                if (colp->co_char == col)
                        return colp->co_bit;
        return 0;
}

static int
get_colmod(int colmod, char *cp)
{
        if ((cp[0] == '\0') ||
            (cp[0] == '!' && cp[1] == '\0'))
                colmod |= lastcolmod;

        for (/*EMPTY*/; *cp; cp++) {
                int colresult;
                if ((colresult = evalcol(*cp)) == 0) {
                        (void)printf("Unknown colon modifier \"%s\"\n", lexstring);
                        return -1;
                }
                if (colresult == CMNEGATE)
                        colmod ^= CMNEGATE;
                else
                        colmod |= colresult;
        }
        return colmod;
}

static int
syntax_error(const char *msg)
{
        (void)printf("Syntax error: %s\n", msg);
        return -1;
}

/*
 * scan out a single lexical item and return its token number,
 * updating the string pointer passed **p.  Also, store the value
 * of the number or string scanned in lexnumber or lexstring as
 * appropriate.  In any event, store the scanned `thing' in lexstring.
 */
static enum token_e
scan(char **sp)
{
        static const struct lex {
                char    l_char;
                enum token_e l_token;
        } singles[] = {
                { '$',  TDOLLAR },
                { '.',  TDOT },
                { '^',  TUP },
                { '*',  TSTAR },
                { '-',  TDASH },
                { '+',  TPLUS },
                { '(',  TOPEN },
                { ')',  TCLOSE },
                { '&',  TAND },
                { '|',  TOR },
                { '!',  TNOT },
                { 0,    0 }
        };
        const struct lex *lp;
        char *cp, *cp2;
        int c;
        int quotec;

        if (regretp >= 0) {
                (void)strcpy(lexstring, string_stack[regretp]);
                lexnumber = numberstack[regretp];
                return regretstack[regretp--];
        }
        cp = *sp;
        cp2 = lexstring;
        lexstring[0] = '\0';

        /*
         * strip away leading white space.
         */
        cp = skip_WSP(cp);

        /*
         * If no characters remain, we are at end of line,
         * so report that.
         */
        if (*cp == '\0') {
                *sp = cp;
                return TEOL;
        }

        /*
         * If the leading character is a digit, scan
         * the number and convert it on the fly.
         * Return TNUMBER when done.
         */
        c = (unsigned char)*cp++;
        if (isdigit(c)) {
                lexnumber = 0;
                while (isdigit(c)) {
                        lexnumber = lexnumber * 10 + c - '0';
                        *cp2++ = c;
                        c = (unsigned char)*cp++;
                }
                *cp2 = '\0';
                *sp = --cp;
                return TNUMBER;
        }

        /*
         * Check for single character tokens; return such
         * if found.
         */
        for (lp = &singles[0]; lp->l_char != 0; lp++)
                if (c == lp->l_char) {
                        lexstring[0] = c;
                        lexstring[1] = '\0';
                        *sp = cp;
                        return lp->l_token;
                }

        /*
         * We've got a string!  Copy all the characters
         * of the string into lexstring, until we see
         * a null, space, or tab.
         * Respect quoting and quoted pairs.
         */
        quotec = 0;
        while (c != '\0') {
                if (c == quotec) {
                        quotec = 0;
                        c = *cp++;
                        continue;
                }
                if (quotec) {
                        if (c == '\\' && (*cp == quotec || *cp == '\\'))
                                c = *cp++;
                }
                else {
                        switch (c) {
                        case '\'':
                        case '"':
                                quotec = c;
                                c = *cp++;
                                continue;
                        case ' ':
                        case '\t':
                                c = '\0';       /* end of token! */
                                continue;
                        default:
                                break;
                        }
                }
                if (cp2 - lexstring < STRINGLEN - 1)
                        *cp2++ = c;
                c = *cp++;
        }
        if (quotec && c == 0) {
                (void)fprintf(stderr, "Missing %c\n", quotec);
                return TERROR;
        }
        *sp = --cp;
        *cp2 = '\0';
        return TSTRING;
}

/*
 * Unscan the named token by pushing it onto the regret stack.
 */
static void
regret(int token)
{
        if (++regretp >= REGDEP)
                errx(EXIT_FAILURE, "Too many regrets");
        regretstack[regretp] = token;
        lexstring[sizeof(lexstring) - 1] = '\0';
        string_stack[regretp] = savestr(lexstring);
        numberstack[regretp] = lexnumber;
}

/*
 * Reset all the scanner global variables.
 */
static void
scaninit(void)
{
        regretp = -1;
}

#define DELIM " \t,"  /* list of string delimiters */
static int
is_substr(const char *big, const char *little)
{
        const char *cp;
        if ((cp = strstr(big, little)) == NULL)
                return 0;

        return strchr(DELIM, cp[strlen(little)]) != 0 &&
            (cp == big || strchr(DELIM, cp[-1]) != 0);
}
#undef DELIM


/*
 * Look for (compiled regex) pattern in a line.
 * Returns:
 *      1 if match found.
 *      0 if no match found.
 *      -1 on error
 */
static int
regexcmp(void *pattern, char *line, size_t len)
{
        regmatch_t pmatch[1];
        regmatch_t *pmp;
        int eflags;
        int rval;
        regex_t *preg;

        preg = pattern;

        if (line == NULL)
                return 0;

        if (len == 0) {
                pmp = NULL;
                eflags = 0;
        }
        else {
                pmatch[0].rm_so = 0;
                pmatch[0].rm_eo = line[len - 1] == '\n' ? len - 1 : len;
                pmp = pmatch;
                eflags = REG_STARTEND;
        }

        switch ((rval = regexec(preg, line, 0, pmp, eflags))) {
        case 0:
        case REG_NOMATCH:
                return rval == 0;

        default: {
                char errbuf[LINESIZE];
                (void)regerror(rval, preg, errbuf, sizeof(errbuf));
                (void)printf("regexec failed: '%s': %s\n", line, errbuf);
                return -1;
        }}
}

/*
 * Look for (string) pattern in line.
 * Return 1 if match found.
 */
static int
substrcmp(void *pattern, char *line, size_t len)
{
        char *substr;
        substr = pattern;

        if (line == NULL)
                return 0;

        if (len) {
                if (line[len - 1] == '\n') {
                        line[len - 1] = '\0';
                }
                else {
                        char *cp;
                        cp = salloc(len + 1);
                        (void)strlcpy(cp, line, len + 1);
                        line = cp;
                }
        }
        return strcasestr(line, substr) != NULL;
}

/*
 * Look for NULL line.  Used to find non-existent fields.
 * Return 1 if match found.
 */
static int
hasfieldcmp(void *pattern __unused, char *line, size_t len __unused)
{
#ifdef __lint__
        pattern = pattern;
        len = len;
#endif
        return line != NULL;
}

static regex_t preg;
/*
 * Determine the compare function and its argument based on the
 * "regex-search" variable.
 */
static int (*
get_cmpfn(void **pattern, char *str)
)(void *, char *, size_t)
{
        char *val;
        int cflags;
        int e;

        if (*str == 0) {
                *pattern = NULL;
                return hasfieldcmp;
        }

        if ((val = value(ENAME_REGEX_SEARCH)) != NULL) {
                cflags = REG_NOSUB;
                val = skip_WSP(val);
                if (*val) {
                        if (is_substr(val, "icase"))
                                cflags |= REG_ICASE;
                        if (is_substr(val, "extended"))
                                cflags |= REG_EXTENDED;
                        /*
                         * NOTE: regcomp() will fail if "nospec" and
                         * "extended" are used together.
                         */
                        if (is_substr(val, "nospec"))
                                cflags |= REG_NOSPEC;
                }
                if ((e = regcomp(&preg, str, cflags)) != 0) {
                        char errbuf[LINESIZE];
                        (void)regerror(e, &preg, errbuf, sizeof(errbuf));
                        (void)printf("regcomp failed: '%s': %s\n", str, errbuf);
                        return NULL;
                }
                *pattern = &preg;
                return regexcmp;
        }

        *pattern = str;
        return substrcmp;
}

/*
 * Free any memory allocated by get_cmpfn()
 */
static void
free_cmparg(void *pattern)
{
        if (pattern == &preg)
                regfree(&preg);
}

/*
 * Check the message body for the pattern.
 */
static int
matchbody(int (*cmpfn)(void *, char *, size_t),
    void *pattern, struct message *mp, char const *fieldname __unused)
{
        FILE *fp;
        char *line;
        size_t len;
        int gotmatch;

#ifdef __lint__
        fieldname = fieldname;
#endif
        /*
         * Get a temporary file.
         */
        {
                char *tempname;
                int fd;

                (void)sasprintf(&tempname, "%s/mail.RbXXXXXXXXXX", tmpdir);
                fp = NULL;
                if ((fd = mkstemp(tempname)) != -1) {
                        (void)unlink(tempname);
                        if ((fp = Fdopen(fd, "wef+")) == NULL)
                                (void)close(fd);
                }
                if (fp == NULL) {
                        warn("%s", tempname);
                        return -1;
                }
        }

        /*
         * Pump the (decoded) message body into the temp file.
         */
        {
#ifdef MIME_SUPPORT
                struct mime_info *mip;
                int retval;

                mip = value(ENAME_MIME_DECODE_MSG) ? mime_decode_open(mp)
                    : NULL;

                retval = mime_sendmessage(mp, fp, ignoreall, NULL, mip);
                mime_decode_close(mip);
                if (retval == -1)
#else
                if (sendmessage(mp, fp, ignoreall, NULL, NULL) == -1)
#endif
                {
                        warn("matchbody: mesg=%d", get_msgnum(mp));
                        return -1;
                }
        }
        /*
         * XXX - should we read the entire body into a buffer so we
         * can search across lines?
         */
        rewind(fp);
        gotmatch = 0;
        while ((line = fgetln(fp, &len)) != NULL && len > 0) {
                gotmatch = cmpfn(pattern, line, len);
                if (gotmatch)
                        break;
        }
        (void)Fclose(fp);

        return gotmatch;
}

/*
 * Check the "To:", "Cc:", and "Bcc" fields for the pattern.
 */
static int
matchto(int (*cmpfn)(void *, char *, size_t),
    void *pattern, struct message *mp, char const *fieldname __unused)
{
        static const char *to_fields[] = { "to", "cc", "bcc", 0 };
        const char **to;
        int gotmatch;

#ifdef __lint__
        fieldname = fieldname;
#endif
        gotmatch = 0;
        for (to = to_fields; *to; to++) {
                char *field;
                field = hfield(*to, mp);
                gotmatch = cmpfn(pattern, field, 0);
                if (gotmatch)
                        break;
        }
        return gotmatch;
}

/*
 * Check a field for the pattern.
 */
static int
matchfield(int (*cmpfn)(void *, char *, size_t),
    void *pattern, struct message *mp, char const *fieldname)
{
        char *field;

#ifdef __lint__
        fieldname = fieldname;
#endif
        field = hfield(fieldname, mp);
        return cmpfn(pattern, field, 0);
}

/*
 * Check the headline for the pattern.
 */
static int
matchfrom(int (*cmpfn)(void *, char *, size_t),
    void *pattern, struct message *mp, char const *fieldname __unused)
{
        char headline[LINESIZE];
        char *field;

#ifdef __lint__
        fieldname = fieldname;
#endif
        (void)readline(setinput(mp), headline, (int)sizeof(headline), 0);
        field = savestr(headline);
        if (strncmp(field, "From ", 5) != 0)
                return 1;

        return cmpfn(pattern, field + 5, 0);
}

/*
 * Check the sender for the pattern.
 */
static int
matchsender(int (*cmpfn)(void *, char *, size_t),
    void *pattern, struct message *mp, char const *fieldname __unused)
{
        char *field;

#ifdef __lint__
        fieldname = fieldname;
#endif
        field = nameof(mp, 0);
        return cmpfn(pattern, field, 0);
}

/*
 * Interpret 'str' and check each message (1 thru 'msgCount') for a match.
 * The 'str' has the format: [/[[x]:]y with the following meanings:
 *
 * y     pattern 'y' is compared against the senders address.
 * /y    pattern 'y' is compared with the subject field.  If 'y' is empty,
 *       the last search 'str' is used.
 * /:y   pattern 'y' is compared with the subject field.
 * /x:y  pattern 'y' is compared with the specified header field 'x' or
 *       the message body if 'x' == "body".
 *
 * The last two forms require "searchheaders" to be defined.
 */
static int
match_string(int *markarray, char *str, int msgCount)
{
        int i;
        int rval;
        int (*matchfn)(int (*)(void *, char *, size_t),
            void *, struct message *, char const *);
        int (*cmpfn)(void *, char *, size_t);
        void *cmparg;
        char const *fieldname;

        if (*str != '/') {
                matchfn = matchsender;
                fieldname = NULL;
        }
        else {
                static char lastscan[STRINGLEN];
                char *cp;

                str++;
                if (*str == '\0')
                        str = lastscan;
                else
                        (void)strlcpy(lastscan, str, sizeof(lastscan));

                if (value(ENAME_SEARCHHEADERS) == NULL ||
                    (cp = strchr(str, ':')) == NULL) {
                        matchfn = matchfield;
                        fieldname = "subject";
                /*      str = str; */
                }
                else {
                        static const struct matchtbl_s {
                                char const *key;
                                size_t len;
                                char const *fieldname;
                                int (*matchfn)(int (*)(void *, char *, size_t),
                                    void *, struct message *, char const *);
                        } matchtbl[] = {
                                #define X(a)    a,      sizeof(a) - 1
                                #define X_NULL  NULL,   0
                                { X(":"),       "subject",      matchfield },
                                { X("body:"),   NULL,           matchbody },
                                { X("from:"),   NULL,           matchfrom },
                                { X("to:"),     NULL,           matchto },
                                { X_NULL,       NULL,           matchfield }
                                #undef X_NULL
                                #undef X
                        };
                        const struct matchtbl_s *mtp;
                        size_t len;
                        /*
                         * Check for special cases!
                         * These checks are case sensitive so the true fields
                         * can be grabbed as mentioned in the manpage.
                         */
                        cp++;
                        len = cp - str;
                        for (mtp = matchtbl; mtp->key; mtp++) {
                                if (len == mtp->len &&
                                    strncmp(str, mtp->key, len) == 0)
                                        break;
                        }
                        matchfn = mtp->matchfn;
                        if (mtp->key)
                                fieldname = mtp->fieldname;
                        else {
                                char *p;
                                p = salloc(len);
                                (void)strlcpy(p, str, len);
                                fieldname = p;
                        }
                        str = cp;
                }
        }

        cmpfn = get_cmpfn(&cmparg, str);
        if (cmpfn == NULL)
                return -1;

        rval = 0;
        for (i = 1; i <= msgCount; i++) {
                struct message *mp;
                mp = get_message(i);
                rval = matchfn(cmpfn, cmparg, mp, fieldname);
                if (rval == -1)
                        break;
                if (rval)
                        markarray[i - 1] = 1;
                rval = 0;
        }

        free_cmparg(cmparg);    /* free any memory allocated by get_cmpfn() */

        return rval;
}


/*
 * Return the message number corresponding to the passed meta character.
 */
static int
metamess(int meta, int f)
{
        int c, m;
        struct message *mp;

        c = meta;
        switch (c) {
        case '^':
                /*
                 * First 'good' message left.
                 */
                for (mp = get_message(1); mp; mp = next_message(mp))
                        if ((mp->m_flag & MDELETED) == f)
                                return get_msgnum(mp);
                (void)printf("No applicable messages\n");
                return -1;

        case '$':
                /*
                 * Last 'good message left.
                 */
                for (mp = get_message(get_msgCount()); mp; mp = prev_message(mp))
                        if ((mp->m_flag & MDELETED) == f)
                                return get_msgnum(mp);
                (void)printf("No applicable messages\n");
                return -1;

        case '.':
                /*
                 * Current message.
                 */
                if (dot == NULL) {
                        (void)printf("No applicable messages\n");
                        return -1;
                }
                m = get_msgnum(dot);
                if ((dot->m_flag & MDELETED) != f) {
                        (void)printf("%d: Inappropriate message\n", m);
                        return -1;
                }
                return m;

        default:
                (void)printf("Unknown metachar (%c)\n", c);
                return -1;
        }
}

/*
 * Check the passed message number for legality and proper flags.
 * If f is MDELETED, then either kind will do.  Otherwise, the message
 * has to be undeleted.
 */
static int
check(int mesg, int f)
{
        struct message *mp;

        if ((mp = get_message(mesg)) == NULL) {
                (void)printf("%d: Invalid message number\n", mesg);
                return -1;
        }
        if (f != MDELETED && (mp->m_flag & MDELETED) != 0) {
                (void)printf("%d: Inappropriate message\n", mesg);
                return -1;
        }
        return 0;
}


static int
markall_core(int *markarray, char **bufp, int f, int level)
{
        enum token_e tok;
        enum logic_op_e {
                LOP_AND,
                LOP_OR,
                LOP_XOR
        } logic_op;             /* binary logic operation */
        int logic_invert;       /* invert the result */
        int *tmparray;  /* temporary array with result */
        int msgCount;   /* tmparray length and message count */
        int beg;        /* first value of a range */
        int colmod;     /* the colon-modifier for this group */
        int got_not;    /* for syntax checking of '!' */
        int got_one;    /* we have a message spec, valid or not */
        int got_bin;    /* we have a pending binary operation */
        int i;

        logic_op = LOP_OR;
        logic_invert = 0;
        colmod = 0;

        msgCount = get_msgCount();
        tmparray = csalloc((size_t)msgCount, sizeof(*tmparray));

        beg = 0;
        got_one = 0;
        got_not = 0;
        got_bin = 0;

        while ((tok = scan(bufp)) != TEOL) {
                if (tok == TERROR)
                        return -1;

                /*
                 * Do some syntax checking.
                 */
                switch (tok) {
                case TDASH:
                case TPLUS:
                case TDOLLAR:
                case TUP:
                case TDOT:
                case TNUMBER:
                        break;

                case TAND:
                case TOR:
                case TXOR:
                        if (!got_one)
                                return syntax_error("missing left operand");
                        /*FALLTHROUGH*/
                default:
                        if (beg)
                                return syntax_error("end of range missing");
                        break;
                }

                /*
                 * The main tok switch.
                 */
                switch (tok) {
                        struct message *mp;

                case TERROR:    /* trapped above */
                case TEOL:
                        assert(/*CONSTCOND*/0);
                        break;

                case TUP:
                        if (got_one) {  /* a possible logical xor */
                                enum token_e t;
                                t = scan(bufp); /* peek ahead */
                                regret(t);
                                lexstring[0] = '^';  /* restore lexstring */
                                lexstring[1] = '\0';
                                if (t != TDASH && t != TEOL && t != TCLOSE) {
                                        /* convert tok to TXOR and put
                                         * it back on the stack so we
                                         * can handle it consistently */
                                        tok = TXOR;
                                        regret(tok);
                                        continue;
                                }
                        }
                        /* FALLTHROUGH */
                case TDOLLAR:
                case TDOT:
                        lexnumber = metamess(lexstring[0], f);
                        if (lexnumber == -1)
                                return -1;
                        /* FALLTHROUGH */
                case TNUMBER:
                        if (check(lexnumber, f))
                                return -1;
        number:
                        got_one = 1;
                        if (beg != 0) {
                                if (lexnumber < beg) {
                                        (void)printf("invalid range: %d-%d\n", beg, lexnumber);
                                        return -1;
                                }
                                for (i = beg; i <= lexnumber; i++)
                                        tmparray[i - 1] = 1;

                                beg = 0;
                                break;
                        }
                        beg = lexnumber;        /* start of a range */
                        tok = scan(bufp);
                        if (tok == TDASH) {
                                continue;
                        }
                        else {
                                regret(tok);
                                tmparray[beg - 1] = 1;
                                beg = 0;
                        }
                        break;

                case TDASH:
                        for (mp = prev_message(dot); mp; mp = prev_message(mp)) {
                                if ((mp->m_flag & MDELETED) == 0)
                                        break;
                        }
                        if (mp == NULL) {
                                (void)printf("Referencing before 1\n");
                                return -1;
                        }
                        lexnumber = get_msgnum(mp);
                        goto number;

                case TPLUS:
                        for (mp = next_message(dot); mp; mp = next_message(mp)) {
                                if ((mp->m_flag & MDELETED) == 0)
                                        break;
                        }
                        if (mp == NULL) {
                                (void)printf("Referencing beyond EOF\n");
                                return -1;
                        }
                        lexnumber = get_msgnum(mp);
                        goto number;

                case TSTRING:
                        if (lexstring[0] == ':') { /* colon modifier! */
                                colmod = get_colmod(colmod, lexstring + 1);
                                if (colmod == -1)
                                        return -1;
                                continue;
                        }
                        got_one = 1;
                        if (match_string(tmparray, lexstring, msgCount) == -1)
                                return -1;
                        break;

                case TSTAR:
                        got_one = 1;
                        for (i = 1; i <= msgCount; i++)
                                tmparray[i - 1] = 1;
                        break;


                        /**************
                         * Parentheses.
                         */
                case TOPEN:
                        if (markall_core(tmparray, bufp, f, level + 1) == -1)
                                return -1;
                        break;

                case TCLOSE:
                        if (level == 0)
                                return syntax_error("extra ')'");
                        goto done;


                        /*********************
                         * Logical operations.
                         */
                case TNOT:
                        got_not = 1;
                        logic_invert = ! logic_invert;
                        continue;

                        /*
                         * Binary operations.
                         */
                case TAND:
                        if (got_not)
                                return syntax_error("'!' precedes '&'");
                        got_bin = 1;
                        logic_op = LOP_AND;
                        continue;

                case TOR:
                        if (got_not)
                                return syntax_error("'!' precedes '|'");
                        got_bin = 1;
                        logic_op = LOP_OR;
                        continue;

                case TXOR:
                        if (got_not)
                                return syntax_error("'!' precedes logical '^'");
                        got_bin = 1;
                        logic_op = LOP_XOR;
                        continue;
                }

                /*
                 * Do the logic operations.
                 */
                if (logic_invert)
                        for (i = 0; i < msgCount; i++)
                                tmparray[i] = ! tmparray[i];

                switch (logic_op) {
                case LOP_AND:
                        for (i = 0; i < msgCount; i++)
                                markarray[i] &= tmparray[i];
                        break;

                case LOP_OR:
                        for (i = 0; i < msgCount; i++)
                                markarray[i] |= tmparray[i];
                        break;

                case LOP_XOR:
                        for (i = 0; i < msgCount; i++)
                                markarray[i] ^= tmparray[i];
                        break;
                }

                /*
                 * Clear the temporary array and reset the logic
                 * operations.
                 */
                for (i = 0; i < msgCount; i++)
                        tmparray[i] = 0;

                logic_op = LOP_OR;
                logic_invert = 0;
                got_not = 0;
                got_bin = 0;
        }

        if (beg)
                return syntax_error("end of range missing");

        if (level)
                return syntax_error("missing ')'");

 done:
        if (got_not)
                return syntax_error("trailing '!'");

        if (got_bin)
                return syntax_error("missing right operand");

        if (colmod != 0) {
                /*
                 * If we have colon-modifiers but no messages
                 * specifiec, then assume '*' was given.
                 */
                if (got_one == 0)
                        for (i = 1; i <= msgCount; i++)
                                markarray[i - 1] = 1;

                for (i = 1; i <= msgCount; i++) {
                        struct message *mp;
                        if ((mp = get_message(i)) != NULL &&
                            ignore_message(mp->m_flag, colmod))
                                markarray[i - 1] = 0;
                }
        }
        return 0;
}

static int
markall(char buf[], int f)
{
        int i;
        int mc;
        int *markarray;
        int msgCount;
        struct message *mp;

        msgCount = get_msgCount();

        /*
         * Clear all the previous message marks.
         */
        for (i = 1; i <= msgCount; i++)
                if ((mp = get_message(i)) != NULL)
                        mp->m_flag &= ~MMARK;

        buf = skip_WSP(buf);
        if (*buf == '\0')
                return 0;

        scaninit();
        markarray = csalloc((size_t)msgCount, sizeof(*markarray));
        if (markall_core(markarray, &buf, f, 0) == -1)
                return -1;

        /*
         * Transfer the markarray values to the messages.
         */
        mc = 0;
        for (i = 1; i <= msgCount; i++) {
                if (markarray[i - 1] &&
                    (mp = get_message(i)) != NULL &&
                    (f == MDELETED || (mp->m_flag & MDELETED) == 0)) {
                        mp->m_flag |= MMARK;
                        mc++;
                }
        }

        if (mc == 0) {
                (void)printf("No applicable messages.\n");
                return -1;
        }
        return 0;
}

/*
 * Convert the user string of message numbers and
 * store the numbers into vector.
 *
 * Returns the count of messages picked up or -1 on error.
 */
PUBLIC int
getmsglist(char *buf, int *vector, int flags)
{
        int *ip;
        struct message *mp;

        if (get_msgCount() == 0) {
                *vector = 0;
                return 0;
        }
        if (markall(buf, flags) < 0)
                return -1;
        ip = vector;
        for (mp = get_message(1); mp; mp = next_message(mp))
                if (mp->m_flag & MMARK)
                        *ip++ = get_msgnum(mp);
        *ip = 0;
        return (int)(ip - vector);
}

/*
 * Find the first message whose flags & m == f  and return
 * its message number.
 */
PUBLIC int
first(int f, int m)
{
        struct message *mp;

        if (get_msgCount() == 0)
                return 0;
        f &= MDELETED;
        m &= MDELETED;
        for (mp = dot; mp; mp = next_message(mp))
                if ((mp->m_flag & m) == f)
                        return get_msgnum(mp);
        for (mp = prev_message(dot); mp; mp = prev_message(mp))
                if ((mp->m_flag & m) == f)
                        return get_msgnum(mp);
        return 0;
}

/*
 * Show all headers without paging.  (-H flag)
 */
__dead
PUBLIC int
show_headers_and_exit(int flags)
{
        struct message *mp;

        /* We are exiting anyway, so use the default signal handler. */
        if (signal(SIGINT, SIG_DFL) == SIG_IGN)
                (void)signal(SIGINT, SIG_IGN);

        flags &= CMMASK;
        for (mp = get_message(1); mp; mp = next_message(mp))
                if (flags == 0 || !ignore_message(mp->m_flag, flags))
                        printhead(get_msgnum(mp));

        exit(0);
        /* NOTREACHED */
}

/*
 * A hack so -H can have an optional modifier as -H[:flags].
 *
 * This depends a bit on the internals of getopt().  In particular,
 * for flags expecting an argument, argv[optind-1] must contain the
 * optarg and optarg must point to a substring of argv[optind-1] not a
 * copy of it.
 */
PUBLIC int
get_Hflag(char **argv)
{
        int flags;

        flags = ~CMMASK;

        if (optarg == NULL)  /* We had an error, just get the flags. */
                return flags;

        if (*optarg != ':' || optarg == argv[optind - 1]) {
                optind--;
                optreset = 1;
                if (optarg != argv[optind]) {
                        static char temparg[LINESIZE];
                        size_t optlen;
                        size_t arglen;
                        char *p;

                        optlen = strlen(optarg);
                        arglen = strlen(argv[optind]);
                        p = argv[optind] + arglen - optlen;
                        optlen = MIN(optlen, sizeof(temparg) - 1);
                        temparg[0] = '-';
                        (void)memmove(temparg + 1, p, optlen + 1);
                        argv[optind] = temparg;
                }
        }
        else {
                flags = get_colmod(flags, optarg + 1);
        }
        return flags;
}