[nmh] / uip / sendsbr.c

/* sendsbr.c -- routines to help WhatNow/Send along
 *
 * 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.
 */

#include <h/mh.h>
#include <h/fmt_scan.h>
#include <h/fmt_compile.h>
#include <h/signals.h>
#include <setjmp.h>
#include <fcntl.h>
#include <h/mime.h>
#include <h/tws.h>
#include <h/utils.h>
#include <h/mts.h>

#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <time.h>

#ifdef OAUTH_SUPPORT
#include <h/oauth.h>
#endif
#include "../sbr/m_mktemp.h"

#ifdef OAUTH_SUPPORT
static int setup_oauth_params(char *[], int *, const char *, const char **);
#endif /* OAUTH_SUPPORT */

int debugsw = 0;                /* global */
int forwsw  = 1;
int inplace = 1;
int pushsw  = 0;
int splitsw = -1;
int unique  = 0;
int verbsw  = 0;

char *altmsg   = NULL;          /*  .. */
char *annotext = NULL;
char *distfile = NULL;

static jmp_buf env;

/*
 * static prototypes
 */
static void alert (char *, int);
static int tmp_fd (void);
static void anno (int, struct stat *);
static void annoaux (int);
static int splitmsg (char **, int, char *, char *, struct stat *, int);
static int sendaux (char **, int, char *, char *, struct stat *);
static void handle_sendfrom(char **, int *, char *, const char *);
static int get_from_header_info(const char *, const char **, const char **, const char **);
static const char *get_message_header_info(FILE *, char *);
static void merge_profile_entry(const char *, const char *, char *[], int *);
static void armed_done (int) NORETURN;

/*
 * Entry point into (back-end) routines to send message.
 */

int
sendsbr (char **vec, int vecp, char *program, char *draft, struct stat *st,
         int rename_drft, const char *auth_svc)
{
    int status, i;
    pid_t child;
    char buffer[BUFSIZ], file[BUFSIZ];
    struct stat sts;
    char **buildvec, *buildprogram;
    char *volatile drft = draft;
    /* nvecs is volatile to prevent warning from gcc about possible clobbering
       by longjmp. */
    volatile int nvecs = vecp;
    int *nvecsp = (int *) &nvecs;

    /*
     * Run the mimebuildproc (which is by default mhbuild) on the message
     * with the addition of the "-auto" flag
     */

    switch (child = fork()) {
    case NOTOK:
        adios("fork", "unable to");
        break;

    case OK:
        buildvec = argsplit(buildmimeproc, &buildprogram, &i);
        buildvec[i++] = "-auto";
        if (distfile)
            buildvec[i++] = "-dist";
        buildvec[i++] = (char *) drft;
        buildvec[i] = NULL;
        execvp(buildprogram, buildvec);
        fprintf(stderr, "unable to exec ");
        perror(buildmimeproc);
        _exit(-1);
        break;

    default:
        if (pidXwait(child, buildmimeproc))
            return NOTOK;
        break;
    }

    done=armed_done;
    switch (setjmp (env)) {
    case OK:
        /*
         * If given -push and -unique (which is undocumented), then
         * rename the draft file.  I'm not quite sure why.
         */
        if (pushsw && unique) {
            char *cp = m_mktemp2(drft, invo_name, NULL, NULL);
            if (cp == NULL) {
                adios(NULL, "unable to create temporary file in %s",
                      get_temp_dir());
            }
            if (rename (drft, strncpy(file, cp, sizeof(file))) == NOTOK)
                adios (file, "unable to rename %s to", drft);
            drft = file;
        }

        /*
         * Add in any necessary profile entries for xoauth
         */

        if (auth_svc) {
#ifdef OAUTH_SUPPORT
                const char *errmsg;
                if (setup_oauth_params(vec, nvecsp, auth_svc, &errmsg) != OK) {
                        adios(NULL, errmsg);
                }
#else
                adios(NULL, "send built without OAUTH_SUPPORT, "
                      "so auth_svc %s is not supported", auth_svc);
#endif /* OAUTH_SUPPORT */
        }

        /*
         * Rework the vec based on From: header in draft, as specified
         * by sendfrom-address entries in profile.
         */
        if (context_find_prefix("sendfrom-")) {
            handle_sendfrom(vec, nvecsp, draft, auth_svc);
        }

        /*
         * Check if we need to split the message into
         * multiple messages of type "message/partial".
         */
        if (splitsw >= 0 && !distfile && stat ((char *) drft, &sts) != NOTOK
                && sts.st_size >= CPERMSG) {
            status = splitmsg (vec, nvecs, program, drft,
                               st, splitsw) ? NOTOK : OK;
        } else {
            status = sendaux (vec, nvecs, program, drft, st) ? NOTOK : OK;
        }

        /* rename the original draft */
        if (rename_drft && status == OK &&
                rename (drft, strncpy (buffer, m_backup (drft),
                                 sizeof(buffer))) == NOTOK)
            advise (buffer, "unable to rename %s to", drft);
        break;

    default:
        status = DONE;
        break;
    }

    done=exit;
    if (distfile)
        (void) m_unlink (distfile);

    return status;
}

/*
 * Split large message into several messages of
 * type "message/partial" and send them.
 */

static int
splitmsg (char **vec, int vecp, char *program, char *drft,
          struct stat *st, int delay)
{
    int compnum, nparts, partno, state, status;
    long pos, start;
    time_t clock;
    char *cp, *dp, buffer[NMH_BUFSIZ], msgid[BUFSIZ];
    char subject[BUFSIZ];
    char name[NAMESZ], partnum[BUFSIZ];
    FILE *in;
    m_getfld_state_t gstate = 0;

    if ((in = fopen (drft, "r")) == NULL)
        adios (drft, "unable to open for reading");

    cp = dp = NULL;
    start = 0L;

    /*
     * Scan through the message and examine the various header fields,
     * as well as locate the beginning of the message body.
     */
    m_getfld_track_filepos (&gstate, in);
    for (compnum = 1;;) {
        int bufsz = sizeof buffer;
        switch (state = m_getfld (&gstate, name, buffer, &bufsz, in)) {
            case FLD:
            case FLDPLUS:
                compnum++;

                /*
                 * This header field is discarded.
                 */
                if (!strcasecmp (name, "Message-ID")) {
                    while (state == FLDPLUS) {
                        bufsz = sizeof buffer;
                        state = m_getfld (&gstate, name, buffer, &bufsz, in);
                    }
                } else if (uprf (name, XXX_FIELD_PRF)
                        || !strcasecmp (name, VRSN_FIELD)
                        || !strcasecmp (name, "Subject")
                        || !strcasecmp (name, "Encrypted")) {
                    /*
                     * These header fields are copied to the enclosed
                     * header of the first message in the collection
                     * of message/partials.  For the "Subject" header
                     * field, we also record it, so that a modified
                     * version of it, can be copied to the header
                     * of each message/partial in the collection.
                     */
                    if (!strcasecmp (name, "Subject")) {
                        size_t sublen;

                        strncpy (subject, buffer, BUFSIZ);
                        sublen = strlen (subject);
                        if (sublen > 0 && subject[sublen - 1] == '\n')
                            subject[sublen - 1] = '\0';
                    }

                    dp = add (concat (name, ":", buffer, NULL), dp);
                    while (state == FLDPLUS) {
                        bufsz = sizeof buffer;
                        state = m_getfld (&gstate, name, buffer, &bufsz, in);
                        dp = add (buffer, dp);
                    }
                } else {
                    /*
                     * These header fields are copied to the header of
                     * each message/partial in the collection.
                     */
                    cp = add (concat (name, ":", buffer, NULL), cp);
                    while (state == FLDPLUS) {
                        bufsz = sizeof buffer;
                        state = m_getfld (&gstate, name, buffer, &bufsz, in);
                        cp = add (buffer, cp);
                    }
                }

                start = ftell (in) + 1;
                continue;

           case BODY:
           case FILEEOF:
                break;

           case LENERR:
           case FMTERR:
                adios (NULL, "message format error in component #%d", compnum);

           default:
                adios (NULL, "getfld () returned %d", state);
        }

        break;
    }
    m_getfld_state_destroy (&gstate);
    if (cp == NULL)
        adios (NULL, "headers missing from draft");

    nparts = 1;
    pos = start;
    while (fgets (buffer, sizeof buffer, in)) {
        long len;

        if ((pos += (len = strlen (buffer))) > CPERMSG) {
            nparts++;
            pos = len;
        }
    }

    /* Only one part, nothing to split */
    if (nparts == 1) {
        free (cp);
        mh_xfree(dp);

        fclose (in);
        return sendaux (vec, vecp, program, drft, st);
    }

    if (!pushsw) {
        printf ("Sending as %d Partial Messages\n", nparts);
        fflush (stdout);
    }
    status = OK;

    vec[vecp++] = "-partno";
    vec[vecp++] = partnum;
    if (delay == 0)
        vec[vecp++] = "-queued";

    time (&clock);
    snprintf (msgid, sizeof(msgid), "%s", message_id (clock, 0));

    fseek (in, start, SEEK_SET);
    for (partno = 1; partno <= nparts; partno++) {
        char tmpdrf[BUFSIZ];
        FILE *out;

        char *cp = m_mktemp2(drft, invo_name, NULL, &out);
        if (cp == NULL) {
            adios(NULL, "unable to create temporary file in %s",
                  get_temp_dir());
        }
        strncpy(tmpdrf, cp, sizeof(tmpdrf));

        /*
         * Output the header fields
         */
        fputs (cp, out);
        fprintf (out, "Subject: %s (part %d of %d)\n", subject, partno, nparts);
        fprintf (out, "%s: %s\n", VRSN_FIELD, VRSN_VALUE);
        fprintf (out, "%s: message/partial; id=\"%s\";\n", TYPE_FIELD, msgid);
        fprintf (out, "\tnumber=%d; total=%d\n", partno, nparts);
        fprintf (out, "%s: part %d of %d\n\n", DESCR_FIELD, partno, nparts);

        /*
         * If this is the first in the collection, output the
         * header fields we are encapsulating at the beginning
         * of the body of the first message.
         */
        if (partno == 1) {
            if (dp)
                fputs (dp, out);
            fprintf (out, "Message-ID: %s\n", msgid);
            fprintf (out, "\n");
        }

        pos = 0;
        for (;;) {
            long len;

            if (!fgets (buffer, sizeof buffer, in)) {
                if (partno == nparts)
                    break;
                adios (NULL, "premature eof");
            }

            if ((pos += (len = strlen (buffer))) > CPERMSG) {
                fseek (in, -len, SEEK_CUR);
                break;
            }

            fputs (buffer, out);
        }

        if (fflush (out))
            adios (tmpdrf, "error writing to");

        fclose (out);

        if (!pushsw && verbsw) {
            putchar('\n');
            fflush (stdout);
        }

        /* Pause here, if a delay is specified */
        if (delay > 0 && 1 < partno && partno <= nparts) {
            if (!pushsw) {
                printf ("pausing %d seconds before sending part %d...\n",
                        delay, partno);
                fflush (stdout);
            }
            sleep ((unsigned int) delay);
        }

        snprintf (partnum, sizeof(partnum), "%d", partno);
        status = sendaux (vec, vecp, program, tmpdrf, st);
        (void) m_unlink (tmpdrf);
        if (status != OK)
            break;

        /*
         * This is so sendaux will only annotate
         * the altmsg the first time it is called.
         */
        annotext = NULL;
    }

    free (cp);
    mh_xfree(dp);

    fclose (in);        /* close the draft */
    return status;
}


/*
 * Annotate original message, and
 * call `postproc' (which is passed down in "program") to send message.
 */

static int
sendaux (char **vec, int vecp, char *program, char *drft, struct stat *st)
{
    pid_t child_id;
    int i, status, fd, fd2;
    char backup[BUFSIZ], buf[BUFSIZ];

    fd = pushsw ? tmp_fd () : NOTOK;
    fd2 = NOTOK;

    if (annotext) {
        if ((fd2 = tmp_fd ()) != NOTOK) {
            vec[vecp++] = "-idanno";
            snprintf (buf, sizeof(buf), "%d", fd2);
            vec[vecp++] = buf;
        } else {
            inform("unable to create temporary file in %s for "
                "annotation list, continuing...", get_temp_dir());
        }
    }
    vec[vecp++] = drft;
    if (distfile && distout (drft, distfile, backup) == NOTOK)
        done (1);
    vec[vecp] = NULL;

    for (i = 0; (child_id = fork()) == NOTOK && i < 5; i++)
        sleep (5);

    switch (child_id) {
    case -1:
        /* oops -- fork error */
        adios ("fork", "unable to");
        break;  /* NOT REACHED */

    case 0:
        /*
         * child process -- send it
         *
         * If fd is OK, then we are pushing and fd points to temp
         * file, so capture anything on stdout and stderr there.
         */
        if (fd != NOTOK) {
            dup2 (fd, fileno (stdout));
            dup2 (fd, fileno (stderr));
            close (fd);
        }
        execvp (program, vec);
        fprintf (stderr, "unable to exec ");
        perror (postproc);
        _exit (-1);

    default:
        /*
         * parent process -- wait for it
         */
        if ((status = pidwait(child_id, NOTOK)) == OK) {
            if (annotext && fd2 != NOTOK)
                anno (fd2, st);
        } else {
            /*
             * If postproc failed, and we have good fd (which means
             * we pushed), then mail error message (and possibly the
             * draft) back to the user.
             */
            if (fd != NOTOK) {
                alert (drft, fd);
                close (fd);
            } else {
                inform("message not delivered to anyone");
            }
            if (annotext && fd2 != NOTOK)
                close (fd2);
            if (distfile) {
                (void) m_unlink (drft);
                if (rename (backup, drft) == NOTOK)
                    advise (drft, "unable to rename %s to", backup);
            }
        }
        break;
    }

    return status;
}


/*
 * Mail error notification (and possibly a copy of the
 * message) back to the user, using the mailproc
 */

static void
alert (char *file, int out)
{
    pid_t child_id;
    int i, in, argp;
    char buf[BUFSIZ];
    char *program;
    char **arglist;

    for (i = 0; (child_id = fork()) == NOTOK && i < 5; i++)
        sleep (5);

    switch (child_id) {
        case NOTOK:
            /* oops -- fork error */
            advise ("fork", "unable to");
            /* FALLTHRU */

        case OK:
            /* child process -- send it */
            SIGNAL (SIGHUP, SIG_IGN);
            SIGNAL (SIGINT, SIG_IGN);
            SIGNAL (SIGQUIT, SIG_IGN);
            SIGNAL (SIGTERM, SIG_IGN);
            if (forwsw) {
                if ((in = open (file, O_RDONLY)) == NOTOK) {
                    admonish (file, "unable to re-open");
                } else {
                    lseek (out, (off_t) 0, SEEK_END);
                    strncpy (buf, "\nMessage not delivered to anyone.\n", sizeof(buf));
                    if (write (out, buf, strlen (buf)) < 0) {
                        advise (file, "write");
                    }
                    strncpy (buf, "\n------- Unsent Draft\n\n", sizeof(buf));
                    if (write (out, buf, strlen (buf)) < 0) {
                        advise (file, "write");
                    }
                    cpydgst (in, out, file, "temporary file");
                    close (in);
                    strncpy (buf, "\n------- End of Unsent Draft\n", sizeof(buf));
                    if (write (out, buf, strlen (buf)) < 0) {
                        advise (file, "write");
                    }
                    if (rename (file, strncpy (buf, m_backup (file), sizeof(buf))) == NOTOK)
                        admonish (buf, "unable to rename %s to", file);
                }
            }
            lseek (out, (off_t) 0, SEEK_SET);
            dup2 (out, fileno (stdin));
            close (out);
            /* create subject for error notification */
            snprintf (buf, sizeof(buf), "send failed on %s",
                        forwsw ? "enclosed draft" : file);

            arglist = argsplit(mailproc, &program, &argp);

            arglist[argp++] = getusername();
            arglist[argp++] = "-subject";
            arglist[argp++] = buf;
            arglist[argp] = NULL;

            execvp (program, arglist);
            fprintf (stderr, "unable to exec ");
            perror (mailproc);
            _exit (-1);

        default:                /* no waiting... */
            break;
    }
}


static int
tmp_fd (void)
{
    int fd;
    char *tfile;

    if ((tfile = m_mktemp2(NULL, invo_name, &fd, NULL)) == NULL) return NOTOK;

    if (debugsw)
        inform("temporary file %s selected", tfile);
    else
        if (m_unlink (tfile) == NOTOK)
            advise (tfile, "unable to remove");

    return fd;
}


static void
anno (int fd, struct stat *st)
{
    pid_t child_id;
    sigset_t set, oset;
    static char *cwd = NULL;
    struct stat st2;

    if (altmsg &&
            (stat (altmsg, &st2) == NOTOK
                || st->st_mtime != st2.st_mtime
                || st->st_dev != st2.st_dev
                || st->st_ino != st2.st_ino)) {
        if (debugsw)
            inform("$mhaltmsg mismatch, continuing...");
        return;
    }

    child_id = debugsw ? NOTOK : fork ();
    switch (child_id) {
        case NOTOK:             /* oops */
            if (!debugsw)
                inform("unable to fork, so doing annotations by hand...");
            if (cwd == NULL)
                cwd = mh_xstrdup(pwd ());
            /* FALLTHRU */

        case OK:
            /* block a few signals */
            sigemptyset (&set);
            sigaddset (&set, SIGHUP);
            sigaddset (&set, SIGINT);
            sigaddset (&set, SIGQUIT);
            sigaddset (&set, SIGTERM);
            sigprocmask (SIG_BLOCK, &set, &oset);

            unregister_for_removal(0);

            annoaux (fd);
            if (child_id == OK)
                _exit (0);

            /* reset the signal mask */
            sigprocmask (SIG_SETMASK, &oset, &set);

            if (chdir (cwd) < 0) {
                advise (cwd, "chdir");
            }
            break;

        default:                /* no waiting... */
            close (fd);
            break;
    }
}


static void
annoaux (int fd)
{
    int fd2, fd3, msgnum;
    char *cp, *folder, *maildir;
    char buffer[BUFSIZ], **ap;
    FILE *fp;
    struct msgs *mp;

    if ((folder = getenv ("mhfolder")) == NULL || *folder == 0) {
        if (debugsw)
            inform("$mhfolder not set, continuing...");
        return;
    }
    maildir = m_maildir (folder);
    if (chdir (maildir) == NOTOK) {
        if (debugsw)
            admonish (maildir, "unable to change directory to");
        return;
    }
    if (!(mp = folder_read (folder, 0))) {
        if (debugsw)
            inform("unable to read folder %s, continuing...", folder);
        return;
    }

    /* check for empty folder */
    if (mp->nummsg == 0) {
        if (debugsw)
            inform("no messages in %s, continuing...", folder);
        goto oops;
    }

    if ((cp = getenv ("mhmessages")) == NULL || *cp == 0) {
        if (debugsw)
            inform("$mhmessages not set, continuing...");
        goto oops;
    }
    if (!debugsw                        /* MOBY HACK... */
            && pushsw
            && (fd3 = open ("/dev/null", O_RDWR)) != NOTOK
            && (fd2 = dup (fileno (stderr))) != NOTOK) {
        dup2 (fd3, fileno (stderr));
        close (fd3);
    }
    else
        fd2 = NOTOK;
    for (ap = brkstring (cp = mh_xstrdup(cp), " ", NULL); *ap; ap++)
        m_convert (mp, *ap);
    free (cp);
    if (fd2 != NOTOK)
        dup2 (fd2, fileno (stderr));
    if (mp->numsel == 0) {
        if (debugsw)
            inform("no messages to annotate, continuing...");
        goto oops;
    }

    lseek (fd, (off_t) 0, SEEK_SET);
    if ((fp = fdopen (fd, "r")) == NULL) {
        if (debugsw)
            inform("unable to fdopen annotation list, continuing...");
        goto oops;
    }
    cp = NULL;
    while (fgets (buffer, sizeof(buffer), fp) != NULL)
        cp = add (buffer, cp);
    fclose (fp);

    if (debugsw)
        inform("annotate%s with %s: \"%s\"",
                inplace ? " inplace" : "", annotext, cp);
    for (msgnum = mp->lowsel; msgnum <= mp->hghsel; msgnum++) {
        if (is_selected(mp, msgnum)) {
            if (debugsw)
                inform("annotate message %d", msgnum);
            annotate (m_name (msgnum), annotext, cp, inplace, 1, -2, 0);
        }
    }

    free (cp);

oops:
    folder_free (mp);   /* free folder/message structure */
}


static
void
handle_sendfrom(char **vec, int *vecp, char *draft, const char *auth_svc) {
    const char *addr, *host;
    const char *message;

    /* Extract address and host from From: header line in draft. */
    if (get_from_header_info(draft, &addr, &host, &message) != OK) {
        adios(draft, message);
    }

    /* Merge in any address or host specific switches to post(1) from profile. */
    merge_profile_entry(addr, host, vec, vecp);
    free((void *) host);
    free((void *) addr);

    vec[*vecp] = NULL;

    {
        char **vp;

        for (vp = vec; *vp; ++vp) {
            if (strcmp(*vp, "xoauth2") == 0) {
#ifdef OAUTH_SUPPORT
                if (setup_oauth_params(vec, vecp, auth_svc, &message) != OK) {
                    adios(NULL, message);
                }
                break;
#else
                NMH_UNUSED(auth_svc);
                adios(NULL, "send built without OAUTH_SUPPORT, "
                      "so -saslmech xoauth2 is not supported");
#endif /* OAUTH_SUPPORT */
            }
        }
    }
}


#ifdef OAUTH_SUPPORT
/*
 * For XOAUTH2, append profile entries so post can do the heavy lifting
 */
static int
setup_oauth_params(char *vec[], int *vecp, const char *auth_svc,
                   const char **message) {
    const char *saslmech = NULL, *user = NULL;
    mh_oauth_service_info svc;
    char errbuf[256];
    int i;

    /* Make sure we have all the information we need. */
    for (i = 1; i < *vecp; ++i) {
        /* Don't support abbreviated switches, to avoid collisions in the
           future if new ones are added. */
        if (! strcmp(vec[i-1], "-saslmech")) {
            saslmech = vec[i];
        } else if (! strcmp(vec[i-1], "-user")) {
            user = vec[i];
        } else if (! strcmp(vec[i-1], "-authservice")) {
            auth_svc = vec[i];
        }
    }

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

        if (saslmech  &&  ! strcasecmp(saslmech, "xoauth2")) {
            if (! mh_oauth_get_service_info(auth_svc, &svc, errbuf,
                                            sizeof(errbuf)))
                adios(NULL, "Unable to retrieve oauth profile entries: %s",
                      errbuf);

            vec[(*vecp)++] = mh_xstrdup("-authservice");
            vec[(*vecp)++] = mh_xstrdup(auth_svc);
            vec[(*vecp)++] = mh_xstrdup("-oauthcredfile");
            vec[(*vecp)++] = mh_xstrdup(mh_oauth_cred_fn(auth_svc));
            vec[(*vecp)++] = mh_xstrdup("-oauthclientid");
            vec[(*vecp)++] = getcpy(svc.client_id);
            vec[(*vecp)++] = mh_xstrdup("-oauthclientsecret");
            vec[(*vecp)++] = getcpy(svc.client_secret);
            vec[(*vecp)++] = mh_xstrdup("-oauthauthendpoint");
            vec[(*vecp)++] = getcpy(svc.auth_endpoint);
            vec[(*vecp)++] = mh_xstrdup("-oauthredirect");
            vec[(*vecp)++] = getcpy(svc.redirect_uri);
            vec[(*vecp)++] = mh_xstrdup("-oauthtokenendpoint");
            vec[(*vecp)++] = getcpy(svc.token_endpoint);
            vec[(*vecp)++] = mh_xstrdup("-oauthscope");
            vec[(*vecp)++] = getcpy(svc.scope);
        }
    }

    return 0;
}
#endif /* OAUTH_SUPPORT */


/*
 * Extract user and domain from From: header line in draft.
 */
static
int
get_from_header_info(const char *filename, const char **addr, const char **host, const char **message) {
    struct stat st;
    FILE *in;

    if (stat (filename, &st) == NOTOK) {
        *message = "unable to stat draft file";
        return NOTOK;
    }

    if ((in = fopen (filename, "r")) != NULL) {
        /* There must be a non-blank Envelope-From or {Resent-}Sender or
           {Resent-}From header. */
        char *addrformat = "%(addr{Envelope-From})";
        char *hostformat = "%(host{Envelope-From})";

        if ((*addr = get_message_header_info (in, addrformat)) == NULL  ||
            !**addr) {
            addrformat = distfile == NULL  ?  "%(addr{Sender})"  :  "%(addr{Resent-Sender})";
            hostformat = distfile == NULL  ?  "%(host{Sender})"  :  "%(host{Resent-Sender})";

            if ((*addr = get_message_header_info (in, addrformat)) == NULL) {
                addrformat = distfile == NULL  ?  "%(addr{From})"  :  "%(addr{Resent-From})";
                hostformat = distfile == NULL  ?  "%(host{From})"  :  "%(host{Resent-From})";

                if ((*addr = get_message_header_info (in, addrformat)) == NULL) {
                    *message = "unable to find sender address in";
                    fclose(in);
                    return NOTOK;
                }
            }
        }

        /* Use the hostformat that corresponds to the successful addrformat. */
        if ((*host = get_message_header_info(in, hostformat)) == NULL) {
            fclose(in);
            *message = "unable to find sender host in";
            fclose(in);
            return NOTOK;
        }
        fclose(in);

        return OK;
    }

    *message = "unable to open";
    return NOTOK;
}


/*
 * Get formatted information from header of a message.
 * Adapted from process_single_file() in uip/fmttest.c.
 */
static
const char *
get_message_header_info(FILE *in, char *format) {
    int dat[5];
    struct format *fmt;
    struct stat st;
    int parsing_header;
    m_getfld_state_t gstate = 0;
    charstring_t buffer = charstring_create(0);
    char *retval;

    dat[0] = dat[1] = dat[4] = 0;
    dat[2] = fstat(fileno(in), &st) == 0  ?  st.st_size  :  0;
    dat[3] = INT_MAX;

    (void) fmt_compile(new_fs(NULL, NULL, format), &fmt, 1);
    free_fs();

    /*
     * Read in the message and process the header.
     */
    rewind (in);
    parsing_header = 1;
    do {
        char name[NAMESZ], rbuf[NMH_BUFSIZ];
        int bufsz = sizeof rbuf;
        int state = m_getfld(&gstate, name, rbuf, &bufsz, in);

        switch (state) {
        case FLD:
        case FLDPLUS: {
            int bucket = fmt_addcomptext(name, rbuf);

            if (bucket != -1) {
                while (state == FLDPLUS) {
                    bufsz = sizeof rbuf;
                    state = m_getfld(&gstate, name, rbuf, &bufsz, in);
                    fmt_appendcomp(bucket, name, rbuf);
                }
            }

            while (state == FLDPLUS) {
                bufsz = sizeof rbuf;
                state = m_getfld(&gstate, name, rbuf, &bufsz, in);
            }
            break;
        }
        default:
            parsing_header = 0;
        }
    } while (parsing_header);
    m_getfld_state_destroy(&gstate);

    fmt_scan(fmt, buffer, INT_MAX, dat, NULL);
    fmt_free(fmt, 1);

    /* Trim trailing newline, if any. */
    retval = rtrim(charstring_buffer_copy((buffer)));
    charstring_free(buffer);
    if (*retval)
        return retval;

    free(retval);
    return NULL;
}


/*
 * Look in profile for entry corresponding to addr or host, and add its contents to vec.
 *
 * Could do some of this automatically, by looking for:
 * 1) access-$(mbox{from}) in oauth-svc file using mh_oauth_cred_load(), which isn't
 *    static and doesn't have side effects; free the result with mh_oauth_cred_free())
 * 2) machine $(mbox{from}) in creds
 * If no -server passed in from profile or commandline, could use smtp.<svc>.com for gmail,
 * but that might not generalize for other svcs.
 */
static
void
merge_profile_entry(const char *addr, const char *host, char *vec[], int *vecp) {
    char *addr_entry = concat("sendfrom-", addr, NULL);
    char *profile_entry = context_find(addr_entry);

    free(addr_entry);
    if (profile_entry == NULL) {
        /* No entry for the user.  Look for one for the host. */
        char *host_entry = concat("sendfrom-", host, NULL);

        profile_entry = context_find(host_entry);
        free(host_entry);
    }

    /* Use argsplit() to do the real work of splitting the args in the profile entry. */
    if (profile_entry && *profile_entry) {
        int profile_vecp;
        char *file;
        char **profile_vec = argsplit(profile_entry, &file, &profile_vecp);
        int i;

        for (i = 0; i < profile_vecp; ++i) {
            vec[(*vecp)++] = getcpy(profile_vec[i]);
        }

        arglist_free(file, profile_vec);
    }
}


static void NORETURN
armed_done (int status)
{
    longjmp (env, status ? status : NOTOK);
}