Simplified m_strn() per Ralph's suggestions.

[nmh] / uip / inc.c

/* inc.c -- incorporate messages from a maildrop into a folder
 *
 * This code is Copyright (c) 2002, by the authors of nmh.  See the
 * COPYRIGHT file in the root directory of the nmh distribution for
 * complete copyright information.
 */

#ifdef MAILGROUP
/*
 * Thu Feb 12 21:00 CST 2015            Marcin Cieslak <saper@saper.info>
 *    Replaced setgid() calls with setegid() so that it works with dot
 *    locking on FreeBSD.  setegid() should be supported on modern POSIX
 *    systems.
 *
 * Revised: Sat Apr 14 17:08:17 PDT 1990 (marvit@hplabs)
 *    Added hpux hacks to set and reset gid to be "mail" as needed. The reset
 *    is necessary so inc'ed mail is the group of the inc'er, rather than
 *    "mail". We setgid to egid only when [un]locking the mail file. This
 *    is also a major security precaution which will not be explained here.
 *
 * Fri Feb  7 16:04:57 PST 1992         John Romine <bug-mh@ics.uci.edu>
 *   NB: I'm not 100% sure that this setgid stuff is secure even now.
 *
 * See the *GROUPPRIVS() macros later. I'm reasonably happy with the setgid
 * attribute. Running setuid root is probably not a terribly good idea, though.
 *       -- Peter Maydell <pmaydell@chiark.greenend.org.uk>, 04/1998
 *
 * Peter Maydell's patch slightly modified for nmh 0.28-pre2.
 * Ruud de Rooij <ruud@debian.org>  Wed, 22 Jul 1998 13:24:22 +0200
 */
#endif

#include <h/mh.h>
#include <h/utils.h>
#include <fcntl.h>
#include <h/dropsbr.h>
#include <h/popsbr.h>
#include <h/fmt_scan.h>
#include <h/scansbr.h>
#include <h/signals.h>
#include <h/tws.h>
#include <h/mts.h>
#include "../sbr/lock_file.h"
#include "../sbr/m_maildir.h"
#include "../sbr/m_mktemp.h"

#ifndef TLS_SUPPORT
# define TLSminc(a) (a)
#else
# define TLSminc(a)  0
#endif

#define INC_SWITCHES \
    X("audit audit-file", 0, AUDSW) \
    X("noaudit", 0, NAUDSW) \
    X("changecur", 0, CHGSW) \
    X("nochangecur", 0, NCHGSW) \
    X("file name", 0, FILESW) \
    X("form formatfile", 0, FORMSW) \
    X("format string", 5, FMTSW) \
    X("host hostname", 0, HOSTSW) \
    X("user username", 0, USERSW) \
    X("port name/number", 0, PORTSW) \
    X("silent", 0, SILSW) \
    X("nosilent", 0, NSILSW) \
    X("truncate", 0, TRNCSW) \
    X("notruncate", 0, NTRNCSW) \
    X("width columns", 0, WIDTHSW) \
    X("version", 0, VERSIONSW) \
    X("help", 0, HELPSW) \
    X("snoop", 0, SNOOPSW) \
    X("sasl", 0, SASLSW) \
    X("nosasl", 0, NOSASLSW) \
    X("saslmech", 0, SASLMECHSW) \
    X("initialtls", TLSminc(-10), INITTLSSW) \
    X("notls", TLSminc(-5), NOTLSSW) \
    X("certverify", TLSminc(-10), CERTVERSW) \
    X("nocertverify", TLSminc(-12), NOCERTVERSW) \
    X("authservice", 0, AUTHSERVICESW) \
    X("proxy command", 0, PROXYSW) \

#define X(sw, minchars, id) id,
DEFINE_SWITCH_ENUM(INC);
#undef X

#define X(sw, minchars, id) { sw, minchars, id },
DEFINE_SWITCH_ARRAY(INC, switches);
#undef X

/*
 * flags for the mail source
 */
#define INC_FILE  0
#define INC_POP   1

static int inc_type;
static struct Maildir_entry {
        char *filename;
        time_t mtime;
} *Maildir = NULL;
static int num_maildir_entries = 0;
static int snoop = 0;

extern char response[];

static long start;
static long stop;

static FILE *pf = NULL;

/* This is an attempt to simplify things by putting all the
 * privilege ops into macros.
 * *GROUPPRIVS() is related to handling the setgid MAIL property,
 * and only applies if MAILGROUP is defined.
 * Basically, SAVEGROUPPRIVS() is called right at the top of main()
 * to initialise things, and then DROPGROUPPRIVS() and GETGROUPPRIVS()
 * do the obvious thing.
 *
 * There's probably a better implementation if we're allowed to use
 * BSD-style setreuid() rather than using POSIX saved-ids.
 * Anyway, if you're euid root it's a bit pointless to drop the group
 * permissions...
 *
 * I'm pretty happy that the security is good provided we aren't setuid root.
 * The only things we trust with group=mail privilege are lkfopen()
 * and lkfclose().
 */

/*
 * For setting and returning to "mail" gid
 */
#ifdef MAILGROUP
static gid_t return_gid;
#define TRYDROPGROUPPRIVS() DROPGROUPPRIVS()
#define DROPGROUPPRIVS() \
    if (setegid(getgid()) != 0) { \
        adios ("setegid", "unable to restore group to %ld", (long) getgid()); \
    }
#define GETGROUPPRIVS() \
    if (setegid(return_gid) != 0) { \
        adios ("setegid", "unable to set group to %ld", (long) return_gid); \
    }
#define SAVEGROUPPRIVS() return_gid = getegid()
#else
/* define *GROUPPRIVS() as null; this avoids having lots of "#ifdef MAILGROUP"s */
#define TRYDROPGROUPPRIVS()
#define DROPGROUPPRIVS()
#define GETGROUPPRIVS()
#define SAVEGROUPPRIVS()
#endif /* not MAILGROUP */

/* these variables have to be globals so that done() can correctly clean up the lockfile */
static int locked = 0;
static char *newmail;
static FILE *in;

/*
 * prototypes
 */
static void inc_done(int) NORETURN;
static int pop_action(char *);

int
maildir_srt(const void *va, const void *vb)
{
    const struct Maildir_entry *a = va, *b = vb;
    if (a->mtime > b->mtime)
      return 1;
    if (a->mtime < b->mtime)
      return -1;
    return 0;
}

int
main (int argc, char **argv)
{
    bool chgflag;
    int trnflag = 1;
    bool noisy;
    int width = -1;
    int hghnum = 0, msgnum = 0;
    bool sasl, tls, noverify;
    int incerr = 0; /* <0 if inc hits an error which means it should not truncate mailspool */
    char *cp, *maildir = NULL, *folder = NULL;
    char *format = NULL, *form = NULL;
    char *host = NULL, *port = NULL, *user = NULL, *proxy = NULL;
    char *audfile = NULL, *from = NULL, *saslmech = NULL, *auth_svc = NULL;
    char buf[BUFSIZ], **argp, *nfs, **arguments;
    struct msgs *mp = NULL;
    struct stat st, s1;
    FILE *aud = NULL;
    char b[PATH_MAX + 1];
    char *maildir_copy = NULL;  /* copy of mail directory because the static gets overwritten */

    int nmsgs, nbytes;
    char *MAILHOST_env_variable;
    done=inc_done;

/* absolutely the first thing we do is save our privileges,
 * and drop them if we can.
 */
    SAVEGROUPPRIVS();
    TRYDROPGROUPPRIVS();

    if (nmh_init(argv[0], 1)) { return 1; }

    mts_init ();
    arguments = getarguments (invo_name, argc, argv, 1);
    argp = arguments;

    /*
     * Scheme is:
     *        use MAILHOST environment variable if present,
     *  else try Hesiod.
     *  If that fails, use the default (if any)
     *  provided by mts.conf in mts_init()
     */
    if ((MAILHOST_env_variable = getenv("MAILHOST")) != NULL)
        pophost = MAILHOST_env_variable;
    /*
     * If there is a valid "pophost" entry in mts.conf,
     * then use it as the default host.
     */
    if (pophost && *pophost)
        host = pophost;

    sasl = tls = false;
    chgflag = noisy = noverify = true;
    while ((cp = *argp++)) {
        if (*cp == '-') {
            switch (smatch (++cp, switches)) {
            case AMBIGSW:
                ambigsw (cp, switches);
                done (1);
            case UNKWNSW:
                adios (NULL, "-%s unknown", cp);

            case HELPSW:
                snprintf (buf, sizeof(buf), "%s [+folder] [switches]", invo_name);
                print_help (buf, switches, 1);
                done (0);
            case VERSIONSW:
                print_version(invo_name);
                done (0);

            case AUDSW:
                if (!(cp = *argp++) || *cp == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                audfile = getcpy (m_maildir (cp));
                continue;
            case NAUDSW:
                audfile = NULL;
                continue;

            case CHGSW:
                chgflag = true;
                continue;
            case NCHGSW:
                chgflag = false;
                continue;

            /*
             * The flag `trnflag' has the value:
             *
             * 2 if -truncate is given
             * 1 by default (truncating is default)
             * 0 if -notruncate is given
             */
            case TRNCSW:
                trnflag = 2;
                continue;
            case NTRNCSW:
                trnflag = 0;
                continue;

            case FILESW:
                if (!(cp = *argp++) || *cp == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                from = path (cp, TFILE);

                /*
                 * If the truncate file is in default state,
                 * change to not truncate.
                 */
                if (trnflag == 1)
                    trnflag = 0;
                continue;

            case SILSW:
                noisy = false;
                continue;
            case NSILSW:
                noisy = true;
                continue;

            case FORMSW:
                if (!(form = *argp++) || *form == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                format = NULL;
                continue;
            case FMTSW:
                if (!(format = *argp++) || *format == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                form = NULL;
                continue;

            case WIDTHSW:
                if (!(cp = *argp++) || *cp == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                width = atoi (cp);
                continue;

            case HOSTSW:
                if (!(host = *argp++) || *host == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                continue;

            case PORTSW:
                if (!(port = *argp++) || *port == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                continue;

            case USERSW:
                if (!(user = *argp++) || *user == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                continue;

            case SNOOPSW:
                snoop++;
                continue;
        
            case SASLSW:
                sasl = true;
                continue;
            case NOSASLSW:
                sasl = false;
                continue;
        
            case SASLMECHSW:
                if (!(saslmech = *argp++) || *saslmech == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                continue;

            case INITTLSSW:
                tls = true;
                continue;

            case NOTLSSW:
                tls = false;
                continue;

            case CERTVERSW:
                noverify = false;
                continue;

            case NOCERTVERSW:
                noverify = true;
                continue;

            case AUTHSERVICESW:
#ifdef OAUTH_SUPPORT
                if (!(auth_svc = *argp++) || *auth_svc == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
#else
                adios (NULL, "not built with OAuth support");
#endif
                continue;

            case PROXYSW:
                if (!(proxy = *argp++) || *proxy == '-')
                    adios (NULL, "missing argument to %s", argp[-2]);
                continue;
            }
        }
        if (*cp == '+' || *cp == '@') {
            if (folder)
                adios (NULL, "only one folder at a time!");
            else
                folder = pluspath (cp);
        } else {
            adios (NULL, "usage: %s [+folder] [switches]", invo_name);
        }
    }

    /* NOTE: above this point you should use TRYDROPGROUPPRIVS(),
     * not DROPGROUPPRIVS().
     */
    if (host && !*host)
        host = NULL;

    /* guarantee dropping group privileges; we might not have done so earlier */
    DROPGROUPPRIVS();

    /*
     * Where are we getting the new mail?
     */
    if (from)
        inc_type = INC_FILE;
    else if (host)
        inc_type = INC_POP;
    else
        inc_type = INC_FILE;

    /*
     * Are we getting the mail from
     * a POP server?
     */
    if (inc_type == INC_POP) {
        int tlsflag = 0;

        if (auth_svc == NULL) {
            if (saslmech  &&  ! strcasecmp(saslmech, "xoauth2")) {
                adios (NULL, "must specify -authservice with -saslmech xoauth2");
            }
        } else {
            if (user == NULL) {
                adios (NULL, "must specify -user with -saslmech xoauth2");
            }
        }

        if (tls)
            tlsflag |= P_INITTLS;

        if (noverify)
            tlsflag |= P_NOVERIFY;

        /*
         * initialize POP connection
         */
        if (pop_init (host, port, user, proxy, snoop, sasl, saslmech,
                      tlsflag, auth_svc) == NOTOK)
            adios (NULL, "%s", response);

        /* Check if there are any messages */
        if (pop_stat (&nmsgs, &nbytes) == NOTOK)
            adios (NULL, "%s", response);

        if (nmsgs == 0) {
            pop_quit();
            adios (NULL, "no mail to incorporate");
        }
    }

    /*
     * We will get the mail from a file
     * (typically the standard maildrop)
     */

    if (inc_type == INC_FILE) {
        if (from)
            newmail = from;
        else if ((newmail = getenv ("MAILDROP")) && *newmail)
            newmail = m_mailpath (newmail);
        else if ((newmail = context_find ("maildrop")) && *newmail)
            newmail = m_mailpath (newmail);
        else {
            newmail = concat (MAILDIR, "/", MAILFIL, NULL);
        }
        if (stat (newmail, &s1) == NOTOK || s1.st_size == 0)
            adios (NULL, "no mail to incorporate");
        if (s1.st_mode & S_IFDIR) {
            DIR *md;
            struct dirent *de;
            struct stat ms;
            int i;
            i = 0;
            cp = concat (newmail, "/new", NULL);
            if ((md = opendir(cp)) == NULL)
                adios (NULL, "unable to open %s", cp);
            while ((de = readdir (md)) != NULL) {
                if (de->d_name[0] == '.')
                    continue;
                if (i >= num_maildir_entries) {
                    if ((Maildir = realloc(Maildir, sizeof(*Maildir) * (2*i+16))) == NULL)
                        adios(NULL, "not enough memory for %d messages", 2*i+16);
                    num_maildir_entries = 2*i+16;
                }
                Maildir[i].filename = concat (cp, "/", de->d_name, NULL);
                if (stat(Maildir[i].filename, &ms) != 0)
                   adios (Maildir[i].filename, "couldn't get delivery time");
                Maildir[i].mtime = ms.st_mtime;
                i++;
            }
            free (cp);
            closedir (md);
            cp = concat (newmail, "/cur", NULL);
            if ((md = opendir(cp)) == NULL)
                adios (NULL, "unable to open %s", cp);
            while ((de = readdir (md)) != NULL) {
                if (de->d_name[0] == '.')
                    continue;
                if (i >= num_maildir_entries) {
                    if ((Maildir = realloc(Maildir, sizeof(*Maildir) * (2*i+16))) == NULL)
                        adios(NULL, "not enough memory for %d messages", 2*i+16);
                    num_maildir_entries = 2*i+16;
                }
                Maildir[i].filename = concat (cp, "/", de->d_name, NULL);
                if (stat(Maildir[i].filename, &ms) != 0)
                   adios (Maildir[i].filename, "couldn't get delivery time");
                Maildir[i].mtime = ms.st_mtime;
                i++;
            }
            free (cp);
            closedir (md);
            if (i == 0)
                adios (NULL, "no mail to incorporate");
            num_maildir_entries = i;
            qsort (Maildir, num_maildir_entries, sizeof(*Maildir), maildir_srt);
        }

        cp = mh_xstrdup(newmail);
        newmail = cp;
    }

    if (!context_find ("path"))
        free (path ("./", TFOLDER));
    if (!folder)
        folder = getfolder (0);
    maildir = m_maildir (folder);
    maildir_copy = mh_xstrdup(maildir);

    if (!folder_exists(maildir)) {
        /* If the folder doesn't exist, and we're given the -silent flag,
         * just fail.
         */
        if (noisy)
            create_folder(maildir, 0, done);
        else
            done (1);
    }

    if (chdir (maildir) == NOTOK)
        adios (maildir, "unable to change directory to");

    /* read folder and create message structure */
    if (!(mp = folder_read (folder, 0)))
        adios (NULL, "unable to read folder %s", folder);

    if (inc_type == INC_FILE && Maildir == NULL) {
        if (access (newmail, W_OK) != NOTOK) {
            locked++;
            if (trnflag) {
                SIGNAL (SIGHUP, SIG_IGN);
                SIGNAL (SIGINT, SIG_IGN);
                SIGNAL (SIGQUIT, SIG_IGN);
                SIGNAL (SIGTERM, SIG_IGN);
            }

            GETGROUPPRIVS();       /* Reset gid to lock mail file */
            in = lkfopenspool (newmail, "r");
            DROPGROUPPRIVS();
            if (in == NULL)
                adios (NULL, "unable to lock and fopen %s", newmail);
            fstat (fileno(in), &s1);
        } else {
            trnflag = 0;
            if ((in = fopen (newmail, "r")) == NULL)
                adios (newmail, "unable to read");
        }
    }

    /* This shouldn't be necessary but it can't hurt. */
    DROPGROUPPRIVS();

    if (audfile) {
        int i;
        if ((i = stat (audfile, &st)) == NOTOK)
            inform("Creating Receive-Audit: %s", audfile);
        if ((aud = fopen (audfile, "a")) == NULL)
            adios (audfile, "unable to append to");
        else if (i == NOTOK)
            chmod (audfile, m_gmprot ());

        if (from)
            fprintf (aud, "<<inc>> %s -ms %s\n", dtimenow(0), from);
        else {
            if (host)
                fprintf (aud, "<<inc>> %s -host %s -user %s\n", dtimenow(0),
                         host, user);
            else
                fprintf (aud, "<<inc>> %s\n", dtimenow (0));
        }
    }

    /* Get new format string */
    nfs = new_fs (form, format, FORMAT);

    if (noisy) {
        printf ("Incorporating new mail into %s...\n\n", folder);
        fflush (stdout);
    }


    /*
     * Get the mail from a POP server
     */
    if (inc_type == INC_POP) {
        int i;

        hghnum = msgnum = mp->hghmsg;
        for (i = 1; i <= nmsgs; i++) {
            charstring_t scanl = NULL;

            msgnum++;
            cp = mh_xstrdup(m_name (msgnum));
            if ((pf = fopen (cp, "w+")) == NULL)
                adios (cp, "unable to write");
            chmod (cp, m_gmprot ());
            start = stop = 0L;

            if (pop_retr (i, pop_action) == NOTOK)
                adios (NULL, "%s", response);

            if (fflush (pf))
                adios (cp, "write error on");
            fseek (pf, 0L, SEEK_SET);
            switch (incerr = scan (pf, msgnum, 0, nfs, width,
                              msgnum == mp->hghmsg + 1 && chgflag,
                              1, NULL, stop - start, noisy, &scanl)) {
            case SCNEOF:
                printf ("%*d  empty\n", DMAXFOLDER, msgnum);
                break;

            case SCNFAT:
                trnflag = 0;
                noisy = true;
                /* advise (cp, "unable to read"); already advised */
                break;

            case SCNERR:
            case SCNNUM:
                break;

            case SCNMSG:
            case SCNENC:
            default:
                if (aud)
                    fputs (charstring_buffer (scanl), aud);
                if (noisy)
                    fflush (stdout);
                break;
            }
            charstring_free (scanl);

            if (ferror(pf) || fclose (pf)) {
                int e = errno;
                (void) m_unlink (cp);
                pop_quit ();
                errno = e;
                adios (cp, "write error on");
            }
            free (cp);

            if (trnflag && pop_dele (i) == NOTOK)
                adios (NULL, "%s", response);

            scan_finished();
        }

        if (pop_quit () == NOTOK)
            adios (NULL, "%s", response);
    }

    /*
     * Get the mail from file (usually mail spool)
     */
    if (inc_type == INC_FILE && Maildir == NULL) {
        scan_detect_mbox_style (in);            /* the MAGIC invocation... */
        hghnum = msgnum = mp->hghmsg;
        for (;;) {
            charstring_t scanl = NULL;

            /* create scanline for new message */
            switch (incerr = scan (in, msgnum + 1, msgnum + 1, nfs, width,
                              msgnum == hghnum && chgflag, 1, NULL, 0L, noisy,
                              &scanl)) {
            case SCNFAT:
            case SCNEOF:
                break;

            case SCNERR:
                if (aud)
                    fputs ("inc aborted!\n", aud);
                inform("aborted!");     /* doesn't clean up locks! */
                break;

            case SCNNUM:
                inform("BUG in %s, number out of range", invo_name);
                break;

            default:
                inform("BUG in %s, scan() botch (%d)", invo_name, incerr);
                break;

            case SCNMSG:
            case SCNENC:
                /*
                 *  Run the external program hook on the message.
                 */

                (void)snprintf(b, sizeof (b), "%s/%d", maildir_copy, msgnum + 1);
                (void)ext_hook("add-hook", b, NULL);

                if (aud)
                    fputs (charstring_buffer (scanl), aud);
                if (noisy)
                    fflush (stdout);

                msgnum++;
                continue;
            }
            charstring_free (scanl);

            /* If we get here there was some sort of error from scan(),
             * so stop processing anything more from the spool.
             */
            break;
        }
    } else if (inc_type == INC_FILE) { /* Maildir inbox to process */
        char *sp;
        FILE *sf;
        int i;

        hghnum = msgnum = mp->hghmsg;
        for (i = 0; i < num_maildir_entries; i++) {
            charstring_t scanl = NULL;

            msgnum++;

            sp = Maildir[i].filename;
            cp = mh_xstrdup(m_name (msgnum));
            pf = NULL;
            if (!trnflag || link(sp, cp) == -1) {
                static char buf[65536];
                size_t nrd;

                if ((sf = fopen (sp, "r")) == NULL)
                    adios (sp, "unable to read for copy");
                if ((pf = fopen (cp, "w+")) == NULL)
                    adios (cp, "unable to write for copy");
                while ((nrd = fread(buf, 1, sizeof(buf), sf)) > 0)
                    if (fwrite(buf, 1, nrd, pf) != nrd)
                        break;
                if (ferror(sf) || fflush(pf) || ferror(pf)) {
                        int e = errno;
                        fclose(pf); fclose(sf); (void) m_unlink(cp);
                        errno = e;
                        adios(cp, "copy error %s -> %s", sp, cp);
                }
                fclose (sf);
                sf = NULL;
            }
            if (pf == NULL && (pf = fopen (cp, "r")) == NULL)
                adios (cp, "not available");
            chmod (cp, m_gmprot ());

            fseek (pf, 0L, SEEK_SET);
            switch (incerr = scan (pf, msgnum, 0, nfs, width,
                              msgnum == mp->hghmsg + 1 && chgflag,
                              1, NULL, stop - start, noisy, &scanl)) {
            case SCNEOF:
                printf ("%*d  empty\n", DMAXFOLDER, msgnum);
                break;

            case SCNFAT:
                trnflag = 0;
                noisy = true;
                /* advise (cp, "unable to read"); already advised */
                break;

            case SCNERR:
            case SCNNUM:
                break;

            case SCNMSG:
            case SCNENC:
            default:
                /*
                 *  Run the external program hook on the message.
                 */

                (void)snprintf(b, sizeof (b), "%s/%d", maildir_copy, msgnum + 1);
                (void)ext_hook("add-hook", b, NULL);

                if (aud)
                    fputs (charstring_buffer (scanl), aud);
                if (noisy)
                    fflush (stdout);
                break;
            }
            charstring_free (scanl);

            if (ferror(pf) || fclose (pf)) {
                int e = errno;
                (void) m_unlink (cp);
                errno = e;
                adios (cp, "write error on");
            }
            pf = NULL;
            free (cp);

            if (trnflag && m_unlink (sp) == NOTOK)
                adios (sp, "couldn't unlink");
            free (sp); /* Free Maildir[i]->filename */

            scan_finished();
        }
        free (Maildir); /* From now on Maildir is just a flag - don't dref! */
    }

    scan_finished ();

    if (incerr < 0) {           /* error */
        if (locked) {
            GETGROUPPRIVS();      /* Be sure we can unlock mail file */
            (void) lkfclosespool (in, newmail); in = NULL;
            DROPGROUPPRIVS();    /* And then return us to normal privileges */
        } else {
            fclose (in); in = NULL;
        }
        adios (NULL, "failed");
    }

    if (aud)
        fclose (aud);

    if (noisy)
        fflush (stdout);

    /*
     * truncate file we are incorporating from
     */
    if (inc_type == INC_FILE && Maildir == NULL) {
        if (trnflag) {
            if (stat (newmail, &st) != NOTOK && s1.st_mtime != st.st_mtime)
                inform("new messages have arrived!\007");
            else {
                int newfd;
                if ((newfd = creat (newmail, 0600)) != NOTOK)
                    close (newfd);
                else
                    admonish (newmail, "error zero'ing");
            }
        } else {
            if (noisy)
                printf ("%s not zero'd\n", newmail);
        }
    }

    if (msgnum == hghnum) {
        inform("no messages incorporated, continuing...");
    } else {
        /*
         * Lock the sequence file now, and loop to set the right flags
         * in the folder structure
         */

        struct msgs *mp2;
        int i;

        context_replace (pfolder, folder);      /* update current folder */

        if ((mp2 = folder_read(folder, 1)) == NULL) {
            inform("Unable to reread folder %s, continuing...", folder);
            goto skip;
        }

        /*
         * Shouldn't happen, but just in case ...
         */

        if (msgnum >= mp2->hghoff
                && !(mp2 = folder_realloc (mp2, mp2->lowoff, msgnum + 1))) {
            inform("unable to reallocate folder storage");
            goto skip;
        }

        if (chgflag)
            mp2->curmsg = hghnum + 1;
        mp2->hghmsg = msgnum;

        if (mp2->lowmsg == 0)
            mp2->lowmsg = 1;
        if (chgflag)            /* sigh... */
            seq_setcur (mp2, mp2->curmsg);

        for (i = hghnum + 1; i <= msgnum; i++) {
            clear_msg_flags (mp2, i);
            set_exists (mp2, i);
            set_unseen (mp2, i);
        }
        mp2->msgflags |= SEQMOD;
        seq_setunseen(mp2, 0);  /* Set the Unseen-Sequence */
        seq_save(mp2);          /* Save the sequence file */
        folder_free(mp2);
    }
skip:

    /*
     * unlock the mail spool
     */
    if (inc_type == INC_FILE && Maildir == NULL) {
        if (locked) {
           GETGROUPPRIVS();        /* Be sure we can unlock mail file */
           (void) lkfclosespool (in, newmail); in = NULL;
           DROPGROUPPRIVS();       /* And then return us to normal privileges */
        } else {
            fclose (in); in = NULL;
        }
    }

    context_save ();            /* save the context file   */
    done (0);
    return 1;
}


static void NORETURN
inc_done (int status)
{
    done = exit;
    if (locked)
    {
        GETGROUPPRIVS();
        lkfclosespool(in, newmail);
        DROPGROUPPRIVS();
    }
    exit (status);
}

static int
pop_action (char *s)
{
    fprintf (pf, "%s\n", s);
    stop += strlen (s) + 1;
    return 0;  /* Is return value used?  This was missing before 1999-07-15. */
}