/*      $NetBSD: fio.c,v 1.46 2026/06/25 22:27:52 kre 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[] = "@(#)fio.c       8.2 (Berkeley) 4/20/95";
#else
__RCSID("$NetBSD: fio.c,v 1.46 2026/06/25 22:27:52 kre Exp $");
#endif
#endif /* not lint */

#include "rcv.h"
#include "extern.h"
#include "thread.h"
#include "sig.h"
#include <wordexp.h>

/*
 * Mail -- a mail program
 *
 * File I/O.
 */

#ifndef THREAD_SUPPORT
/************************************************************************/
/*
 * If we have threading support, these routines live in thread.c.
 */
static struct message *message;         /* message structure array */
static int msgCount;                    /* Count of messages read in */

PUBLIC struct message *
next_message(struct message *mp)
{
        if (mp + 1 < message || mp + 1 >= message + msgCount)
                return NULL;

        return mp + 1;
}

PUBLIC struct message *
prev_message(struct message *mp)
{
        if (mp - 1 < message || mp - 1 >= message + msgCount)
                return NULL;

        return mp - 1;
}

PUBLIC struct message *
get_message(int msgnum)
{
        if (msgnum < 1 || msgnum > msgCount)
                return NULL;

        return message + msgnum - 1;
}

PUBLIC int
get_msgnum(struct message *mp)
{
        if (mp < message || mp >= message + msgCount)
                return 0;

        return mp - message + 1;
}

PUBLIC int
get_msgCount(void)
{
        return msgCount;
}
#endif /* THREAD_SUPPORT */
/************************************************************************/

/*
 * Initialize a message structure.
 */
static void
message_init(struct message *mp, off_t offset, short flags)
{
        /* use memset so new fields are always zeroed */
        (void)memset(mp, 0, sizeof(*mp));
        mp->m_flag = flags;
        mp->m_block = blockof(offset);
        mp->m_offset = blkoffsetof(offset);
}

/*
 * Take the data out of the passed ghost file and toss it into
 * a dynamically allocated message structure.
 */
static void
makemessage(FILE *f, int omsgCount, int nmsgCount)
{
        ssize_t size;
        struct message *omessage;       /* old message structure array */
        struct message *nmessage;
        ptrdiff_t off;

#ifndef min
#define min(a, b) ((a) < (b) ? (a) : (b))       /* caution, args eval'd twice */
#endif

        omessage = get_abs_message(1);

        size = (nmsgCount + 1) * sizeof(*nmessage);

        if (omsgCount == 0 || omessage == NULL)
                off = 0;
        else
                off = dot - omessage;
        thread_save_old_links(omessage, omsgCount);
        nmessage = realloc(omessage, size);
        if (nmessage == NULL)
                err(EXIT_FAILURE,
                    "Insufficient memory for %d messages", nmsgCount);
        dot = nmessage + off;

        thread_fix_old_links(nmessage, min(omsgCount, nmsgCount));

#ifndef THREAD_SUPPORT
        message = nmessage;
#endif
        size -= (omsgCount + 1) * sizeof(*nmessage);
        if (size >= 0) {
                (void)fflush(f);
                (void)lseek(fileno(f), (off_t)sizeof(*nmessage), SEEK_SET);
                if (read(fileno(f), &nmessage[omsgCount], (size_t)size) != size)
                        errx(EXIT_FAILURE, "Message temporary file corrupted");
        }

        message_init(&nmessage[nmsgCount], (off_t)0, 0); /* append a dummy */

        thread_fix_new_links(nmessage, omsgCount, nmsgCount);

        (void)Fclose(f);
}

/*
 * Append the passed message descriptor onto the temp file.
 * If the write fails, return 1, else 0
 */
static int
append(struct message *mp, FILE *f)
{
        return fwrite(mp, sizeof(*mp), 1, f) != 1;
}

/*
 * Set up the input pointers while copying the mail file into /tmp.
 */
PUBLIC void
setptr(FILE *ibuf, off_t offset)
{
        int c;
        size_t len;
        char *cp;
        const char *cp2;
        struct message this;
        FILE *mestmp;
        int maybe, inhead;
        char linebuf[LINESIZE];
        int omsgCount;
#ifdef THREAD_SUPPORT
        int nmsgCount;
#else
# define nmsgCount      msgCount
#endif

        /* Get temporary file. */
        (void)snprintf(linebuf, LINESIZE, "%s/mail.XXXXXX", tmpdir);
        if ((c = mkstemp(linebuf)) == -1 ||
            (mestmp = Fdopen(c, "ref+")) == NULL) {
                (void)fprintf(stderr, "mail: can't open %s\n", linebuf);
                exit(1);
        }
        (void)unlink(linebuf);

        nmsgCount = get_abs_msgCount();
        if (offset == 0) {
                nmsgCount = 0;
        } else {
                /* Seek into the file to get to the new messages */
                (void)fseeko(ibuf, offset, 0);
                /*
                 * We need to make "offset" a pointer to the end of
                 * the temp file that has the copy of the mail file.
                 * If any messages have been edited, this will be
                 * different from the offset into the mail file.
                 */
                (void)fseek(otf, 0L, SEEK_END);
                offset = ftell(otf);
        }
        omsgCount = nmsgCount;
        maybe = 1;
        inhead = 0;
        message_init(&this, (off_t)0, MUSED|MNEW);

        for (;;) {
                if (fgets(linebuf, LINESIZE, ibuf) == NULL) {
                        if (append(&this, mestmp))
                                err(EXIT_FAILURE, "temporary file");
                        makemessage(mestmp, omsgCount, nmsgCount);
                        return;
                }
                len = strlen(linebuf);
                /*
                 * Transforms lines ending in <CR><LF> to just <LF>.
                 * This allows mail to be able to read Eudora mailboxes
                 * that reside on a DOS partition.
                 */
                if (len >= 2 && linebuf[len - 1] == '\n' &&
                    linebuf[len - 2] == '\r') {
                        linebuf[len - 2] = '\n';
                        len--;
                }
                (void)fwrite(linebuf, sizeof(*linebuf), len, otf);
                if (ferror(otf))
                        err(EXIT_FAILURE, "/tmp");
                if (len)
                        linebuf[len - 1] = 0;
                if (maybe && linebuf[0] == 'F' && ishead(linebuf)) {
                        nmsgCount++;
                        if (append(&this, mestmp))
                                err(EXIT_FAILURE, "temporary file");
                        message_init(&this, offset, MUSED|MNEW);
                        inhead = 1;
                } else if (linebuf[0] == 0) {
                        inhead = 0;
                } else if (inhead) {
                        for (cp = linebuf, cp2 = "status";; cp++) {
                                if ((c = *cp2++) == 0) {
                                        while (isspace((unsigned char)*cp++))
                                                continue;
                                        if (cp[-1] != ':')
                                                break;
                                        while ((c = *cp++) != '\0')
                                                if (c == 'R')
                                                        this.m_flag |= MREAD;
                                                else if (c == 'O')
                                                        this.m_flag &= ~MNEW;
                                        inhead = 0;
                                        break;
                                }
                                if (*cp != c && *cp != toupper(c))
                                        break;
                        }
                }
                offset += len;
                this.m_size += len;
                this.m_lines++;
                if (!inhead) {
                        int lines_plus_wraps = 1;
                        int linelen = (int)strlen(linebuf);

                        if (screenwidth && (int)linelen > screenwidth) {
                                lines_plus_wraps = linelen / screenwidth;
                                if (linelen % screenwidth != 0)
                                        ++lines_plus_wraps;
                        }
                        this.m_blines += lines_plus_wraps;
                }
                maybe = linebuf[0] == 0;
        }
}

/*
 * Drop the passed line onto the passed output buffer.
 * If a write error occurs, return -1, else the count of
 * characters written, including the newline if requested.
 */
PUBLIC int
putline(FILE *obuf, const char *linebuf, int outlf)
{
        size_t c;

        c = strlen(linebuf);
        (void)fwrite(linebuf, sizeof(*linebuf), c, obuf);
        if (outlf) {
                (void)putc('\n', obuf);
                c++;
        }
        if (ferror(obuf))
                return -1;
        return (int)c;
}

/*
 * Read up a line from the specified input into the line
 * buffer.  Return the number of characters read.  Do not
 * include the newline at the end.
 */
PUBLIC int
readline(FILE *ibuf, char *linebuf, int linesize, int no_restart)
{
        struct sigaction osa_sigtstp;
        struct sigaction osa_sigttin;
        struct sigaction osa_sigttou;
        int n;

        clearerr(ibuf);

        sig_check();
        if (no_restart) {
                (void)sig_setflags(SIGTSTP, 0, &osa_sigtstp);
                (void)sig_setflags(SIGTTIN, 0, &osa_sigttin);
                (void)sig_setflags(SIGTTOU, 0, &osa_sigttou);
        }
        if (fgets(linebuf, linesize, ibuf) == NULL)
                n = -1;
        else {
                n = (int)strlen(linebuf);
                if (n > 0 && linebuf[n - 1] == '\n')
                        linebuf[--n] = '\0';
        }
        if (no_restart) {
                (void)sigaction(SIGTSTP, &osa_sigtstp, NULL);
                (void)sigaction(SIGTTIN, &osa_sigttin, NULL);
                (void)sigaction(SIGTTOU, &osa_sigttou, NULL);
        }
        sig_check();
        return n;
}

/*
 * Return a file buffer all ready to read up the
 * passed message pointer.
 */
PUBLIC FILE *
setinput(const struct message *mp)
{

        (void)fflush(otf);
        if (fseek(itf, (long)positionof(mp->m_block, mp->m_offset), SEEK_SET) < 0)
                err(EXIT_FAILURE, "fseek");
        return itf;
}

/*
 * Delete a file, but only if the file is a plain file.
 */
PUBLIC int
rm(char *name)
{
        struct stat sb;

        if (stat(name, &sb) < 0)
                return -1;
        if (!S_ISREG(sb.st_mode)) {
                errno = EISDIR;
                return -1;
        }
        return unlink(name);
}

/*
 * Determine the size of the file possessed by
 * the passed buffer.
 */
PUBLIC off_t
fsize(FILE *iob)
{
        struct stat sbuf;

        if (fstat(fileno(iob), &sbuf) < 0)
                return 0;
        return sbuf.st_size;
}

/*
 * Determine the current folder directory name.
 */
PUBLIC int
getfold(char *name, size_t namesize)
{
        char unres[PATHSIZE], res[PATHSIZE];
        char *folder;

        if ((folder = value(ENAME_FOLDER)) == NULL)
                return -1;
        if (*folder != '/') {
                (void)snprintf(unres, sizeof(unres), "%s/%s", homedir, folder);
                folder = unres;
        }
        if (realpath(folder, res) == NULL)
                warn("Can't canonicalize folder `%s'", folder);
        else
                folder = res;
        (void)strlcpy(name, folder, namesize);
        return 0;
}

/*
 * Evaluate the string given as a new mailbox name.
 * Supported meta characters:
 *      %       for my system mail box
 *      %user   for user's system mail box
 *      #       for previous file
 *      &       invoker's mbox file
 *      +file   file in folder directory
 *      any shell meta character
 * Return the file name as a dynamic string.
 */
PUBLIC const char *
expand(const char *name)
{
        char xname[PATHSIZE];
        char cmdbuf[PATHSIZE];
        int e;
        wordexp_t we; 
        sigset_t nset, oset;

        /*
         * The order of evaluation is "%" and "#" expand into constants.
         * "&" can expand into "+".  "+" can expand into shell meta characters.
         * Shell meta characters expand into constants.
         * This way, we make no recursive expansion.
         */
        switch (*name) {
        case '%':
                findmail(name[1] ? name + 1 : myname, xname, sizeof(xname));
                return savestr(xname);
        case '#':
                if (name[1] != 0)
                        break;
                if (prevfile[0] == 0) {
                        warnx("No previous file");
                        return NULL;
                }
                return savestr(prevfile);
        case '&':
                if (name[1] == 0 && (name = value(ENAME_MBOX)) == NULL)
                        name = "~/mbox";
                /* fall through */
        }
        if (name[0] == '+' && getfold(cmdbuf, sizeof(cmdbuf)) >= 0) {
                (void)snprintf(xname, sizeof(xname), "%s/%s", cmdbuf, name + 1);
                name = savestr(xname);
        }
        /* catch the most common shell meta character */
        if (name[0] == '~' && (name[1] == '/' || name[1] == '\0')) {
                (void)snprintf(xname, sizeof(xname), "%s%s", homedir, name + 1);
                name = savestr(xname);
        }
        if (strpbrk(name, "~{[*?$`'\"\\") == NULL)
                return name;

        *xname = '\0';

        sigemptyset(&nset);
        sigaddset(&nset, SIGCHLD);
        sigprocmask(SIG_BLOCK, &nset, &oset);
        e = wordexp(name, &we, WRDE_NOCMD);
        sigprocmask(SIG_SETMASK, &oset, NULL);

        switch (e) {
        case 0: /* OK */
                break;
        case WRDE_NOSPACE:
                warnx("Out of memory expanding `%s'", name);
                return NULL;
        case WRDE_BADVAL:
        case WRDE_BADCHAR:
        case WRDE_SYNTAX:
                warnx("Syntax error expanding `%s'", name);
                return NULL;
        case WRDE_CMDSUB:
                warnx("Command substitution not allowed expanding `%s'",
                    name);
                return NULL;
        default:
                warnx("Unknown expansion error %d expanding `%s'", e, name);
                return NULL;
        }

        switch (we.we_wordc) {
        case 0:
                warnx("No match for `%s'", name);
                break;
        case 1:
                if (strlen(we.we_wordv[0]) >= PATHSIZE)
                        warnx("Expansion too long for `%s'", name);
                strlcpy(xname, we.we_wordv[0], PATHSIZE);
                break;
        default:
                warnx("Ambiguous expansion for `%s'", name);
                break;
        }

        wordfree(&we);
        if (!*xname)
                return NULL;
        else
                return savestr(xname);
}

/*
 * Return the name of the dead.letter file.
 */
PUBLIC const char *
getdeadletter(void)
{
        const char *cp;

        if ((cp = value(ENAME_DEAD)) == NULL || (cp = expand(cp)) == NULL)
                cp = expand("~/dead.letter");
        else if (*cp != '/') {
                char buf[PATHSIZE];
                (void)snprintf(buf, sizeof(buf), "~/%s", cp);
                cp = expand(buf);
        }
        return cp;
}