/*      $NetBSD: support.c,v 1.27 2023/09/08 20:46:45 shm 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[] = "@(#)aux.c       8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: support.c,v 1.27 2023/09/08 20:46:45 shm Exp $");
#endif
#endif /* not lint */

#include <stdarg.h>
#include <util.h>

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

/*
 * Mail -- a mail program
 *
 * Auxiliary functions.
 */


/*
 * Return a pointer to a dynamic copy of the argument.
 */
PUBLIC char *
savestr(const char *str)
{
        char *new;
        size_t size = strlen(str) + 1;

        if ((new = salloc(size)) != NULL)
                (void)memmove(new, str, size);
        return new;
}

/*
 * Make a copy of new argument incorporating old one.
 */
static char *
save2str(char *str, char *old)
{
        char *new;
        size_t newsize = strlen(str) + 1;
        size_t oldsize = old ? strlen(old) + 1 : 0;

        if ((new = salloc(newsize + oldsize)) != NULL) {
                if (oldsize) {
                        (void)memmove(new, old, oldsize);
                        new[oldsize - 1] = ' ';
                }
                (void)memmove(new + oldsize, str, newsize);
        }
        return new;
}

/*
 * Like asprintf(), but with result salloc-ed rather than malloc-ed.
 */
PUBLIC int
sasprintf(char **ret, const char *format, ...)
{
        int rval;
        char *p;
        va_list args;

        va_start(args, format);
        rval = evasprintf(&p, format, args);
        *ret = savestr(p);
        free(p);
        va_end(args);
        return rval;
}

struct set_m_flag_args_s {
        int and_bits;
        int xor_bits;
};
static int
set_m_flag_core(struct message *mp, void *v)
{
        struct set_m_flag_args_s *args;
        args = v;
        mp->m_flag &= args->and_bits;
        mp->m_flag ^= args->xor_bits;
        return 0;
}

PUBLIC struct message *
set_m_flag(int msgnum, int and_bits, int xor_bits)
{
        struct message *mp;
        struct set_m_flag_args_s args;
        mp = get_message(msgnum);
        args.and_bits = and_bits;
        args.xor_bits = xor_bits;
        (void)thread_recursion(mp, set_m_flag_core, &args);
        return mp;
}

/*
 * Touch the named message by setting its MTOUCH flag.
 * Touched messages have the effect of not being sent
 * back to the system mailbox on exit.
 */
PUBLIC void
touch(struct message *mp)
{

        mp->m_flag |= MTOUCH;
        if ((mp->m_flag & MREAD) == 0)
                mp->m_flag |= MREAD|MSTATUS;
}

/*
 * Test to see if the passed file name is a directory.
 * Return true if it is.
 */
PUBLIC int
isdir(const char name[])
{
        struct stat sbuf;

        if (stat(name, &sbuf) < 0)
                return 0;
        return S_ISDIR(sbuf.st_mode);
}

/*
 * Count the number of arguments in the given string raw list.
 */
PUBLIC int
argcount(char **argv)
{
        char **ap;

        for (ap = argv; *ap++ != NULL; /*EMPTY*/)
                continue;
        return (int)(ap - argv - 1);
}

/*
 * Check whether the passed line is a header line of
 * the desired breed.  Return the field body, or NULL.
 */
static char*
ishfield(const char linebuf[], char *colon, const char field[])
{
        char *cp = colon;

        *cp = 0;
        if (strcasecmp(linebuf, field) != 0) {
                *cp = ':';
                return NULL;
        }
        *cp = ':';
        for (cp++; is_WSP(*cp); cp++)
                continue;
        return cp;
}

/*
 * Return the next header field found in the given message.
 * Return >= 0 if something found, < 0 elsewise.
 * "colon" is set to point to the colon in the header.
 * Must deal with \ continuations & other such fraud.
 *
 * WARNING - do not call this outside hfield() or decoding will not
 *           get done.
 */
static int
gethfield(FILE *f, char linebuf[], int rem, char **colon)
{
        char line2[LINESIZE];
        char *cp, *cp2;
        int c;

        for (;;) {
                if (--rem < 0)
                        return -1;
                if ((c = readline(f, linebuf, LINESIZE, 0)) <= 0)
                        return -1;
                for (cp = linebuf;
                     isprint((unsigned char)*cp) && *cp != ' ' && *cp != ':';
                     cp++)
                        continue;
                if (*cp != ':' || cp == linebuf)
                        continue;
                /*
                 * I guess we got a headline.
                 * Handle wraparounding
                 */
                *colon = cp;
                cp = linebuf + c;
                for (;;) {
                        while (--cp >= linebuf && is_WSP(*cp))
                                continue;
                        cp++;
                        if (rem <= 0)
                                break;
                        (void)ungetc(c = getc(f), f);
                        if (!is_WSP(c))
                                break;
                        if ((c = readline(f, line2, LINESIZE, 0)) < 0)
                                break;
                        rem--;
                        cp2 = skip_WSP(line2);
                        c -= (int)(cp2 - line2);
                        if (cp + c >= linebuf + LINESIZE - 2)
                                break;
                        *cp++ = ' ';
                        (void)memmove(cp, cp2, (size_t)c);
                        cp += c;
                }
                *cp = 0;
                return rem;
        }
        /* NOTREACHED */
}

/*
 * Return the desired header line from the passed message
 * pointer (or NULL if the desired header field is not available).
 */
PUBLIC char *
hfield(const char field[], const struct message *mp)
{
        FILE *ibuf;
        char linebuf[LINESIZE];
        int lc;
        char *headerfield;
        char *colon, *oldhfield = NULL;
#ifdef MIME_SUPPORT
        int decode;

        decode = value(ENAME_MIME_DECODE_MSG) &&
            value(ENAME_MIME_DECODE_HDR);
#endif

        ibuf = setinput(mp);
        if ((lc = (int)(mp->m_lines - 1)) < 0)
                return NULL;
        if (readline(ibuf, linebuf, LINESIZE, 0) < 0)
                return NULL;
        while (lc > 0) {
                if ((lc = gethfield(ibuf, linebuf, lc, &colon)) < 0)
                        return oldhfield;
#ifdef MIME_SUPPORT
                if ((headerfield = ishfield(linebuf, colon, field)) != NULL) {
                        char linebuf2[LINESIZE];
                        if (decode)
                                headerfield = mime_decode_hfield(linebuf2,
                                    sizeof(linebuf2), linebuf, headerfield);
                        oldhfield = save2str(headerfield, oldhfield);
                }
#else
                if ((headerfield = ishfield(linebuf, colon, field)) != NULL)
                        oldhfield = save2str(headerfield, oldhfield);
#endif
        }
        return oldhfield;
}

/*
 * Copy a string, lowercasing it as we go.
 */
PUBLIC void
istrcpy(char *dest, const char *src)
{

        do {
                *dest++ = tolower((unsigned char)*src);
        } while (*src++ != 0);
}

/*
 * The following code deals with input stacking to do source
 * commands.  All but the current file pointer are saved on
 * the stack.
 */

static  int     ssp;                    /* Top of file stack */
static struct sstack {
        FILE    *s_file;                /* File we were in. */
        int     s_cond;                 /* Saved state of conditionals */
#ifdef NEW_CONDITIONAL
        struct cond_stack_s *s_cond_stack; /* Saved conditional stack */
#endif
        int     s_loading;              /* Loading .mailrc, etc. */
} sstack[NOFILE];

/*
 * Pushdown current input file and switch to a new one.
 * Set the global flag "sourcing" so that others will realize
 * that they are no longer reading from a tty (in all probability).
 */
PUBLIC int
source(void *v)
{
        char **arglist = v;
        FILE *fi;
        const char *cp;

        if ((cp = expand(*arglist)) == NULL)
                return 1;
        if ((fi = Fopen(cp, "ref")) == NULL) {
                warn("%s", cp);
                return 1;
        }
        if (ssp >= NOFILE - 1) {
                (void)printf("Too much \"sourcing\" going on.\n");
                (void)Fclose(fi);
                return 1;
        }
        sstack[ssp].s_file = input;
        sstack[ssp].s_cond = cond;
#ifdef NEW_CONDITIONAL
        sstack[ssp].s_cond_stack = cond_stack;
#endif
        sstack[ssp].s_loading = loading;
        ssp++;
        loading = 0;
        cond = CNONE;
        input = fi;
        sourcing++;
        return 0;
}

/*
 * Pop the current input back to the previous level.
 * Update the "sourcing" flag as appropriate.
 */
PUBLIC int
unstack(void)
{
        if (ssp <= 0) {
                (void)printf("\"Source\" stack over-pop.\n");
                sourcing = 0;
                return 1;
        }
        (void)Fclose(input);
        if (cond != CNONE || cond_stack != NULL)
                (void)printf("Unmatched \"if\"\n");
        ssp--;
        input = sstack[ssp].s_file;
        cond = sstack[ssp].s_cond;
#ifdef NEW_CONDITIONAL
        cond_stack = sstack[ssp].s_cond_stack;
#endif
        loading = sstack[ssp].s_loading;
        if (ssp == 0)
                sourcing = loading;
        return 0;
}

/*
 * Touch the indicated file.
 * This is nifty for the shell.
 */
PUBLIC void
alter(char *name)
{
        struct stat sb;
        struct timeval tv[2];

        if (stat(name, &sb))
                return;
        (void)gettimeofday(&tv[0], NULL);
        tv[0].tv_sec++;
        TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec);
        (void)utimes(name, tv);
}

/*
 * Examine the passed line buffer and
 * return true if it is all blanks and tabs.
 */
PUBLIC int
blankline(char linebuf[])
{
        char *cp;

        for (cp = linebuf; *cp; cp++)
                if (!is_WSP(*cp))
                        return 0;
        return 1;
}

/*
 * Start of a "comment".
 * Ignore it.
 */
static char *
skip_comment(char *cp)
{
        int nesting = 1;

        for (/*EMPTY*/; nesting > 0 && *cp; cp++) {
                switch (*cp) {
                case '\\':
                        if (cp[1])
                                cp++;
                        break;
                case '(':
                        nesting++;
                        break;
                case ')':
                        nesting--;
                        break;
                }
        }
        return cp;
}

/*
 * Skin an arpa net address according to the RFC 822 interpretation
 * of "host-phrase."
 */
PUBLIC char *
skin(char *name)
{
        int c;
        char *cp, *cp2;
        char *bufend;
        int gotlt, lastsp;
        char *nbuf, *ret;

        if (name == NULL)
                return NULL;
        if (strchr(name, '(') == NULL && strchr(name, '<') == NULL
            && strchr(name, ' ') == NULL)
                return name;

        nbuf = emalloc(strlen(name) + 1); 
        gotlt = 0;
        lastsp = 0;
        bufend = nbuf;
        for (cp = name, cp2 = bufend; (c = *cp++) != '\0'; /*EMPTY*/) {
                switch (c) {
                case '(':
                        cp = skip_comment(cp);
                        lastsp = 0;
                        break;

                case '"':
                        /*
                         * Start of a "quoted-string".
                         * Copy it in its entirety.
                         */
                        while ((c = *cp) != '\0') {
                                cp++;
                                if (c == '"')
                                        break;
                                if (c != '\\')
                                        *cp2++ = c;
                                else if ((c = *cp) != '\0') {
                                        *cp2++ = c;
                                        cp++;
                                }
                        }
                        lastsp = 0;
                        break;

                case ' ':
                        if (cp[0] == 'a' && cp[1] == 't' && cp[2] == ' ')
                                cp += 3, *cp2++ = '@';
                        else
                        if (cp[0] == '@' && cp[1] == ' ')
                                cp += 2, *cp2++ = '@';
                        else
                                lastsp = 1;
                        break;

                case '<':
                        cp2 = bufend;
                        gotlt++;
                        lastsp = 0;
                        break;

                case '>':
                        if (gotlt) {
                                gotlt = 0;
                                while ((c = *cp) && c != ',') {
                                        cp++;
                                        if (c == '(')
                                                cp = skip_comment(cp);
                                        else if (c == '"')
                                                while ((c = *cp) != '\0') {
                                                        cp++;
                                                        if (c == '"')
                                                                break;
                                                        if (c == '\\' && *cp)
                                                                cp++;
                                                }
                                }
                                lastsp = 0;
                                break;
                        }
                        /* FALLTHROUGH */

                default:
                        if (lastsp) {
                                lastsp = 0;
                                *cp2++ = ' ';
                        }
                        *cp2++ = c;
                        if (c == ',' && *cp == ' ' && !gotlt) {
                                *cp2++ = ' ';
                                for (/*EMPTY*/; *cp == ' '; cp++)
                                        continue;
                                lastsp = 0;
                                bufend = cp2;
                        }
                }
        }
        *cp2 = 0;
        
        ret = savestr(nbuf);
        free(nbuf);

        return ret;
}

/*
 * Fetch the sender's name from the passed message.
 * Reptype can be
 *      0 -- get sender's name for display purposes
 *      1 -- get sender's name for reply
 *      2 -- get sender's name for Reply
 */
static char *
name1(struct message *mp, int reptype)
{
        char namebuf[LINESIZE];
        char linebuf[LINESIZE];
        char *cp, *cp2;
        FILE *ibuf;
        int firstrun = 1;

        if ((cp = hfield("from", mp)) != NULL)
                return cp;
        if (reptype == 0 && (cp = hfield("sender", mp)) != NULL)
                return cp;
        ibuf = setinput(mp);
        namebuf[0] = '\0';
        if (readline(ibuf, linebuf, LINESIZE, 0) < 0)
                return savestr(namebuf);
 newname:
        for (cp = linebuf; *cp && *cp != ' '; cp++)
                continue;
        cp = skip_WSP(cp);
        for (cp2 = &namebuf[strlen(namebuf)];
             *cp && !is_WSP(*cp) && cp2 < namebuf + LINESIZE - 1;
             /*EMPTY*/)
                *cp2++ = *cp++;
        *cp2 = '\0';
        if (readline(ibuf, linebuf, LINESIZE, 0) < 0)
                return savestr(namebuf);
        if ((cp = strchr(linebuf, 'F')) == NULL)
                return savestr(namebuf);
        if (strncmp(cp, "From", 4) != 0)
                return savestr(namebuf);
        while ((cp = strchr(cp, 'r')) != NULL) {
                if (strncmp(cp, "remote", 6) == 0) {
                        if ((cp = strchr(cp, 'f')) == NULL)
                                break;
                        if (strncmp(cp, "from", 4) != 0)
                                break;
                        if ((cp = strchr(cp, ' ')) == NULL)
                                break;
                        cp++;
                        if (firstrun) {
                                cp2 = namebuf;
                                firstrun = 0;
                        } else
                                cp2 = strrchr(namebuf, '!') + 1;
                        while (*cp && cp2 < namebuf + LINESIZE - 1)
                                *cp2++ = *cp++;
                        if (cp2 < namebuf + LINESIZE - 1)
                                *cp2++ = '!';
                        *cp2 = '\0';
                        if (cp2 < namebuf + LINESIZE - 1)
                                goto newname;
                        else
                                break;
                }
                cp++;
        }
        return savestr(namebuf);
}

/*
 * Count the occurrences of c in str
 */
static int
charcount(char *str, int c)
{
        char *cp;
        int i;

        for (i = 0, cp = str; *cp; cp++)
                if (*cp == c)
                        i++;
        return i;
}

/*
 * Get sender's name from this message.  If the message has
 * a bunch of arpanet stuff in it, we may have to skin the name
 * before returning it.
 */
PUBLIC char *
nameof(struct message *mp, int reptype)
{
        char *cp, *cp2;

        cp = skin(name1(mp, reptype));
        if (reptype != 0 || charcount(cp, '!') < 2)
                return cp;
        cp2 = strrchr(cp, '!');
        cp2--;
        while (cp2 > cp && *cp2 != '!')
                cp2--;
        if (*cp2 == '!')
                return cp2 + 1;
        return cp;
}

/*
 * Copy s1 to s2, return pointer to null in s2.
 */
PUBLIC char *
copy(char *s1, char *s2)
{

        while ((*s2++ = *s1++) != '\0')
                continue;
        return s2 - 1;
}

/*
 * The core routine to check the ignore table for a field.
 * Note: realfield should be lower-cased!
 */
PUBLIC int
member(char *realfield, struct ignoretab *table)
{
        struct ignore *igp;

        for (igp = table->i_head[hash(realfield)]; igp != 0; igp = igp->i_link)
                if (*igp->i_field == *realfield &&
                    equal(igp->i_field, realfield))
                        return 1;
        return 0;
}

/*
 * See if the given header field is supposed to be ignored.
 */
PUBLIC int
isign(const char *field, struct ignoretab ignoretabs[2])
{
        char realfld[LINESIZE];

        if (ignoretabs == ignoreall)
                return 1;
        /*
         * Lower-case the string, so that "Status" and "status"
         * will hash to the same place.
         */
        istrcpy(realfld, field);
        if (ignoretabs[1].i_count > 0)
                return !member(realfld, ignoretabs + 1);
        else
                return member(realfld, ignoretabs);
}

PUBLIC void
add_ignore(const char *name, struct ignoretab *tab)
{
        char field[LINESIZE];
        int h;
        struct ignore *igp;

        istrcpy(field, name);
        if (member(field, tab))
                return;
        h = hash(field);
        igp = ecalloc(1, sizeof(struct ignore));
        igp->i_field = ecalloc(strlen(field) + 1, sizeof(char));
        (void)strcpy(igp->i_field, field);
        igp->i_link = tab->i_head[h];
        tab->i_head[h] = igp;
        tab->i_count++;
}

/*
 * Write a file to stdout, skipping comment lines.
 */
PUBLIC void
cathelp(const char *fname)
{
        char *line;
        FILE *f;
        size_t len;

        if ((f = Fopen(fname, "ref")) == NULL) {
                warn("%s", fname);
                return;
        }
        while ((line = fgetln(f, &len)) != NULL) {
                if (*line == '#')
                        continue;
                if (fwrite(line, 1, len, stdout) != len)
                        break;
        }
        (void)Fclose(f);
        return;
}