[nmh] / uip / mhbuildsbr.c

/*
 * mhbuildsbr.c -- routines to expand/translate MIME composition files
 *
 * 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.
 */

/*
 * This code was originally part of mhn.c.  I split it into
 * a separate program (mhbuild.c) and then later split it
 * again (mhbuildsbr.c).  But the code still has some of
 * the mhn.c code in it.  This program needs additional
 * streamlining and removal of unneeded code.
 */

#include <h/mh.h>
#include <fcntl.h>
#include <h/signals.h>
#include <h/md5.h>
#include <errno.h>
#include <signal.h>
#include <h/mts.h>
#include <h/tws.h>
#include <h/mime.h>
#include <h/mhparse.h>
#include <h/utils.h>

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


extern int debugsw;
extern int verbosw;

extern int listsw;
extern int rfc934sw;
extern int contentidsw;

/* cache policies */
extern int rcachesw;    /* mhcachesbr.c */
extern int wcachesw;    /* mhcachesbr.c */

/*
 * Directory to place tmp files.  This must
 * be set before these routines are called.
 */
char *tmp;

pid_t xpid = 0;

static char prefix[] = "----- =_aaaaaaaaaa";

/*
 * Maximum size of URL token in message/external-body
 */

#define MAXURLTOKEN 40


/* mhmisc.c */
void content_error (char *, CT, char *, ...);

/* mhcachesbr.c */
int find_cache (CT, int, int *, char *, char *, int);

/* mhfree.c */
void free_ctinfo (CT);
void free_encoding (CT, int);

/*
 * prototypes
 */
CT build_mime (char *, int);

/*
 * static prototypes
 */
static int init_decoded_content (CT);
static char *fgetstr (char *, int, FILE *);
static int user_content (FILE *, char *, char *, CT *);
static void set_id (CT, int);
static int compose_content (CT);
static int scan_content (CT);
static int build_headers (CT);
static char *calculate_digest (CT, int);


static unsigned char directives_stack[32];
static unsigned int directives_index;

static int do_direct(void)
{
    return directives_stack[directives_index];
}

static void directive_onoff(int onoff)
{
    if (directives_index >= sizeof(directives_stack) - 1) {
        fprintf(stderr, "mhbuild: #on/off overflow, continuing\n");
        return;
    }
    directives_stack[++directives_index] = onoff;
}

static void directive_init(int onoff)
{
    directives_index = 0;
    directives_stack[0] = onoff;
}

static void directive_pop(void)
{
    if (directives_index > 0)
        directives_index--;
    else
        fprintf(stderr, "mhbuild: #pop underflow, continuing\n");
}

/*
 * Main routine for translating composition file
 * into valid MIME message.  It translates the draft
 * into a content structure (actually a tree of content
 * structures).  This message then can be manipulated
 * in various ways, including being output via
 * output_message().
 */

CT
build_mime (char *infile, int directives)
{
    int compnum, state;
    char buf[BUFSIZ], name[NAMESZ];
    char *cp, *np, *vp;
    struct multipart *m;
    struct part **pp;
    CT ct;
    FILE *in;
    m_getfld_state_t gstate = 0;

    directive_init(directives);

    umask (~m_gmprot ());

    /* open the composition draft */
    if ((in = fopen (infile, "r")) == NULL)
        adios (infile, "unable to open for reading");

    /*
     * Allocate space for primary (outside) content
     */
    if ((ct = (CT) calloc (1, sizeof(*ct))) == NULL)
        adios (NULL, "out of memory");

    /*
     * Allocate structure for handling decoded content
     * for this part.  We don't really need this, but
     * allocate it to remain consistent.
     */
    init_decoded_content (ct);

    /*
     * Parse some of the header fields in the composition
     * draft into the linked list of header fields for
     * the new MIME message.
     */
    m_getfld_track_filepos (&gstate, in);
    for (compnum = 1;;) {
        int bufsz = sizeof buf;
        switch (state = m_getfld (&gstate, name, buf, &bufsz, in)) {
        case FLD:
        case FLDPLUS:
            compnum++;

            /* abort if draft has Mime-Version header field */
            if (!strcasecmp (name, VRSN_FIELD))
                adios (NULL, "draft shouldn't contain %s: field", VRSN_FIELD);

            /* abort if draft has Content-Transfer-Encoding header field */
            if (!strcasecmp (name, ENCODING_FIELD))
                adios (NULL, "draft shouldn't contain %s: field", ENCODING_FIELD);

            /* ignore any Content-Type fields in the header */
            if (!strcasecmp (name, TYPE_FIELD)) {
                while (state == FLDPLUS) {
                    bufsz = sizeof buf;
                    state = m_getfld (&gstate, name, buf, &bufsz, in);
                }
                goto finish_field;
            }

            /* get copies of the buffers */
            np = add (name, NULL);
            vp = add (buf, NULL);

            /* if necessary, get rest of field */
            while (state == FLDPLUS) {
                bufsz = sizeof buf;
                state = m_getfld (&gstate, name, buf, &bufsz, in);
                vp = add (buf, vp);     /* add to previous value */
            }

            /* Now add the header data to the list */
            add_header (ct, np, vp);

finish_field:
            /* if this wasn't the last header field, then continue */
            continue;

        case FILEEOF:
            adios (NULL, "draft has empty body -- no directives!");
            /* NOTREACHED */

        case BODY:
            fseek (in, (long) (-strlen (buf)), SEEK_CUR);
            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);

    /*
     * Now add the MIME-Version header field
     * to the list of header fields.
     */
    np = add (VRSN_FIELD, NULL);
    vp = concat (" ", VRSN_VALUE, "\n", NULL);
    add_header (ct, np, vp);

    /*
     * We initally assume we will find multiple contents in the
     * draft.  So create a multipart/mixed content to hold everything.
     * We can remove this later, if it is not needed.
     */
    if (get_ctinfo ("multipart/mixed", ct, 0) == NOTOK)
        done (1);
    ct->c_type = CT_MULTIPART;
    ct->c_subtype = MULTI_MIXED;
    ct->c_file = add (infile, NULL);

    if ((m = (struct multipart *) calloc (1, sizeof(*m))) == NULL)
        adios (NULL, "out of memory");
    ct->c_ctparams = (void *) m;
    pp = &m->mp_parts;

    /*
     * read and parse the composition file
     * and the directives it contains.
     */
    while (fgetstr (buf, sizeof(buf) - 1, in)) {
        struct part *part;
        CT p;

        if (user_content (in, infile, buf, &p) == DONE) {
            admonish (NULL, "ignoring spurious #end");
            continue;
        }
        if (!p)
            continue;

        if ((part = (struct part *) calloc (1, sizeof(*part))) == NULL)
            adios (NULL, "out of memory");
        *pp = part;
        pp = &part->mp_next;
        part->mp_part = p;
    }

    /*
     * close the composition draft since
     * it's not needed any longer.
     */
    fclose (in);

    /* check if any contents were found */
    if (!m->mp_parts)
        adios (NULL, "no content directives found");

    /*
     * If only one content was found, then remove and
     * free the outer multipart content.
     */
    if (!m->mp_parts->mp_next) {
        CT p;

        p = m->mp_parts->mp_part;
        m->mp_parts->mp_part = NULL;

        /* move header fields */
        p->c_first_hf = ct->c_first_hf;
        p->c_last_hf = ct->c_last_hf;
        ct->c_first_hf = NULL;
        ct->c_last_hf = NULL;

        free_content (ct);
        ct = p;
    } else {
        set_id (ct, 1);
    }

    /*
     * Fill out, or expand directives.  Parse and execute
     * commands specified by profile composition strings.
     */
    compose_content (ct);

    if ((cp = strchr(prefix, 'a')) == NULL)
        adios (NULL, "internal error(4)");

    /*
     * Scan the contents.  Choose a transfer encoding, and
     * check if prefix for multipart boundary clashes with
     * any of the contents.
     */
    while (scan_content (ct) == NOTOK) {
        if (*cp < 'z') {
            (*cp)++;
        } else {
            if (*++cp == 0)
                adios (NULL, "giving up trying to find a unique delimiter string");
            else
                (*cp)++;
        }
    }

    /* Build the rest of the header field structures */
    build_headers (ct);

    return ct;
}


/*
 * Set up structures for placing unencoded
 * content when building parts.
 */

static int
init_decoded_content (CT ct)
{
    ct->c_ceopenfnx  = open7Bit;        /* since unencoded */
    ct->c_ceclosefnx = close_encoding;
    ct->c_cesizefnx  = NULL;            /* since unencoded */

    return OK;
}


static char *
fgetstr (char *s, int n, FILE *stream)
{
    char *cp, *ep;
    int o_n = n;

    while(1) {
        for (ep = (cp = s) + o_n; cp < ep; ) {
            int i;

            if (!fgets (cp, n, stream))
                return (cp != s ? s : NULL);

            if (cp == s && *cp != '#')
                return s;

            cp += (i = strlen (cp)) - 1;
            if (i <= 1 || *cp-- != '\n' || *cp != '\\')
                break;
            *cp = '\0';
            n -= (i - 2);
        }

        if (strcmp(s, "#on\n") == 0) {
            directive_onoff(1);
        } else if (strcmp(s, "#off\n") == 0) {
            directive_onoff(0);
        } else if (strcmp(s, "#pop\n") == 0) {
            directive_pop();
        } else {
            break;
        }
    }

    return s;
}


/*
 * Parse the composition draft for text and directives.
 * Do initial setup of Content structure.
 */

static int
user_content (FILE *in, char *file, char *buf, CT *ctp)
{
    int extrnal, vrsn;
    char *cp, **ap;
    char buffer[BUFSIZ];
    struct multipart *m;
    struct part **pp;
    struct stat st;
    struct str2init *s2i;
    CI ci;
    CT ct;
    CE ce;

    if (buf[0] == '\n' || (do_direct() && strcmp (buf, "#\n") == 0)) {
        *ctp = NULL;
        return OK;
    }

    /* allocate basic Content structure */
    if ((ct = (CT) calloc (1, sizeof(*ct))) == NULL)
        adios (NULL, "out of memory");
    *ctp = ct;

    /* allocate basic structure for handling decoded content */
    init_decoded_content (ct);
    ce = &ct->c_cefile;

    ci = &ct->c_ctinfo;
    set_id (ct, 0);

    /*
     * Handle inline text.  Check if line
     * is one of the following forms:
     *
     * 1) doesn't begin with '#'        (implicit directive)
     * 2) begins with "##"              (implicit directive)
     * 3) begins with "#<"
     */
    if (!do_direct() || buf[0] != '#' || buf[1] == '#' || buf[1] == '<') {
        int headers;
        int inlineD;
        long pos;
        char content[BUFSIZ];
        FILE *out;
        char *cp;

        cp = m_mktemp2(NULL, invo_name, NULL, &out);
        if (cp == NULL) adios("mhbuildsbr", "unable to create temporary file");

        /* use a temp file to collect the plain text lines */
        ce->ce_file = add (cp, NULL);
        ce->ce_unlink = 1;

        if (do_direct() && (buf[0] == '#' && buf[1] == '<')) {
            strncpy (content, buf + 2, sizeof(content));
            inlineD = 1;
            goto rock_and_roll;
        } else {
            inlineD = 0;
        }

        /* the directive is implicit */
        strncpy (content, "text/plain", sizeof(content));
        headers = 0;
        strncpy (buffer, (!do_direct() || buf[0] != '#') ? buf : buf + 1, sizeof(buffer));
        for (;;) {
            int i;

            if (headers >= 0 && do_direct() && uprf (buffer, DESCR_FIELD)
                && buffer[i = strlen (DESCR_FIELD)] == ':') {
                headers = 1;

again_descr:
                ct->c_descr = add (buffer + i + 1, ct->c_descr);
                if (!fgetstr (buffer, sizeof(buffer) - 1, in))
                    adios (NULL, "end-of-file after %s: field in plaintext", DESCR_FIELD);
                switch (buffer[0]) {
                case ' ':
                case '\t':
                    i = -1;
                    goto again_descr;

                case '#':
                    adios (NULL, "#-directive after %s: field in plaintext", DESCR_FIELD);
                    /* NOTREACHED */

                default:
                    break;
                }
            }

            if (headers >= 0 && do_direct() && uprf (buffer, DISPO_FIELD)
                && buffer[i = strlen (DISPO_FIELD)] == ':') {
                headers = 1;

again_dispo:
                ct->c_dispo = add (buffer + i + 1, ct->c_dispo);
                if (!fgetstr (buffer, sizeof(buffer) - 1, in))
                    adios (NULL, "end-of-file after %s: field in plaintext", DISPO_FIELD);
                switch (buffer[0]) {
                case ' ':
                case '\t':
                    i = -1;
                    goto again_dispo;

                case '#':
                    adios (NULL, "#-directive after %s: field in plaintext", DISPO_FIELD);
                    /* NOTREACHED */

                default:
                    break;
                }
            }

            if (headers != 1 || buffer[0] != '\n')
                fputs (buffer, out);

rock_and_roll:
            headers = -1;
            pos = ftell (in);
            if ((cp = fgetstr (buffer, sizeof(buffer) - 1, in)) == NULL)
                break;
            if (do_direct() && buffer[0] == '#') {
                char *bp;

                if (buffer[1] != '#')
                    break;
                for (cp = (bp = buffer) + 1; *cp; cp++)
                    *bp++ = *cp;
                *bp = '\0';
            }
        }

        if (listsw)
            ct->c_end = ftell (out);
        fclose (out);

        /* parse content type */
        if (get_ctinfo (content, ct, inlineD) == NOTOK)
            done (1);

        for (s2i = str2cts; s2i->si_key; s2i++)
            if (!strcasecmp (ci->ci_type, s2i->si_key))
                break;
        if (!s2i->si_key && !uprf (ci->ci_type, "X-"))
            s2i++;

        /*
         * check type specified (possibly implicitly)
         */
        switch (ct->c_type = s2i->si_val) {
        case CT_MESSAGE:
            if (!strcasecmp (ci->ci_subtype, "rfc822")) {
                ct->c_encoding = CE_7BIT;
                goto call_init;
            }
            /* else fall... */
        case CT_MULTIPART:
            adios (NULL, "it doesn't make sense to define an in-line %s content",
                   ct->c_type == CT_MESSAGE ? "message" : "multipart");
            /* NOTREACHED */

        default:
call_init:
            if ((ct->c_ctinitfnx = s2i->si_init))
                (*ct->c_ctinitfnx) (ct);
            break;
        }

        if (cp)
            fseek (in, pos, SEEK_SET);
        return OK;
    }

    /*
     * If we've reached this point, the next line
     * must be some type of explicit directive.
     */

    /* check if directive is external-type */
    extrnal = (buf[1] == '@');

    /* parse directive */
    if (get_ctinfo (buf + (extrnal ? 2 : 1), ct, 1) == NOTOK)
        done (1);

    /* check directive against the list of MIME types */
    for (s2i = str2cts; s2i->si_key; s2i++)
        if (!strcasecmp (ci->ci_type, s2i->si_key))
            break;

    /*
     * Check if the directive specified a valid type.
     * This will happen if it was one of the following forms:
     *
     *    #type/subtype  (or)
     *    #@type/subtype
     */
    if (s2i->si_key) {
        if (!ci->ci_subtype)
            adios (NULL, "missing subtype in \"#%s\"", ci->ci_type);

        switch (ct->c_type = s2i->si_val) {
        case CT_MULTIPART:
            adios (NULL, "use \"#begin ... #end\" instead of \"#%s/%s\"",
                   ci->ci_type, ci->ci_subtype);
            /* NOTREACHED */

        case CT_MESSAGE:
            if (!strcasecmp (ci->ci_subtype, "partial"))
                adios (NULL, "sorry, \"#%s/%s\" isn't supported",
                       ci->ci_type, ci->ci_subtype);
            if (!strcasecmp (ci->ci_subtype, "external-body"))
                adios (NULL, "use \"#@type/subtype ... [] ...\" instead of \"#%s/%s\"",
                       ci->ci_type, ci->ci_subtype);
use_forw:
            adios (NULL,
                   "use \"#forw [+folder] [msgs]\" instead of \"#%s/%s\"",
                   ci->ci_type, ci->ci_subtype);
            /* NOTREACHED */

        default:
            if ((ct->c_ctinitfnx = s2i->si_init))
                (*ct->c_ctinitfnx) (ct);
            break;
        }

        /*
         * #@type/subtype (external types directive)
         */
        if (extrnal) {
            struct exbody *e;
            CT p;

            if (!ci->ci_magic)
                adios (NULL, "need external information for \"#@%s/%s\"",
                       ci->ci_type, ci->ci_subtype);
            p = ct;

            snprintf (buffer, sizeof(buffer), "message/external-body; %s", ci->ci_magic);
            free (ci->ci_magic);
            ci->ci_magic = NULL;

            /*
             * Since we are using the current Content structure to
             * hold information about the type of the external
             * reference, we need to create another Content structure
             * for the message/external-body to wrap it in.
             */
            if ((ct = (CT) calloc (1, sizeof(*ct))) == NULL)
                adios (NULL, "out of memory");
            *ctp = ct;
            ci = &ct->c_ctinfo;
            if (get_ctinfo (buffer, ct, 0) == NOTOK)
                done (1);
            ct->c_type = CT_MESSAGE;
            ct->c_subtype = MESSAGE_EXTERNAL;

            if ((e = (struct exbody *) calloc (1, sizeof(*e))) == NULL)
                adios (NULL, "out of memory");
            ct->c_ctparams = (void *) e;

            e->eb_parent = ct;
            e->eb_content = p;
            p->c_ctexbody = e;

            if (params_external (ct, 1) == NOTOK)
                done (1);

            return OK;
        }

        /* Handle [file] argument */
        if (ci->ci_magic) {
            /* check if specifies command to execute */
            if (*ci->ci_magic == '|' || *ci->ci_magic == '!') {
                for (cp = ci->ci_magic + 1; isspace ((unsigned char) *cp); cp++)
                    continue;
                if (!*cp)
                    adios (NULL, "empty pipe command for #%s directive", ci->ci_type);
                cp = add (cp, NULL);
                free (ci->ci_magic);
                ci->ci_magic = cp;
            } else {
                /* record filename of decoded contents */
                ce->ce_file = ci->ci_magic;
                if (access (ce->ce_file, R_OK) == NOTOK)
                    adios ("reading", "unable to access %s for", ce->ce_file);
                if (listsw && stat (ce->ce_file, &st) != NOTOK)
                    ct->c_end = (long) st.st_size;
                ci->ci_magic = NULL;
            }
            return OK;
        }

        /*
         * No [file] argument, so check profile for
         * method to compose content.
         */
        snprintf (buffer, sizeof(buffer), "%s-compose-%s/%s",
                invo_name, ci->ci_type, ci->ci_subtype);
        if ((cp = context_find (buffer)) == NULL || *cp == '\0') {
            snprintf (buffer, sizeof(buffer), "%s-compose-%s", invo_name, ci->ci_type);
            if ((cp = context_find (buffer)) == NULL || *cp == '\0') {
                content_error (NULL, ct, "don't know how to compose content");
                done (1);
            }
        }
        ci->ci_magic = add (cp, NULL);
        return OK;
    }

    if (extrnal)
        adios (NULL, "external definition not allowed for \"#%s\"", ci->ci_type);

    /*
     * Message directive
     * #forw [+folder] [msgs]
     */
    if (!strcasecmp (ci->ci_type, "forw")) {
        int msgnum;
        char *folder, *arguments[MAXARGS];
        struct msgs *mp;

        if (ci->ci_magic) {
            ap = brkstring (ci->ci_magic, " ", "\n");
            copyip (ap, arguments, MAXARGS);
        } else {
            arguments[0] = "cur";
            arguments[1] = NULL;
        }
        folder = NULL;

        /* search the arguments for a folder name */
        for (ap = arguments; *ap; ap++) {
            cp = *ap;
            if (*cp == '+' || *cp == '@') {
                if (folder)
                    adios (NULL, "only one folder per #forw directive");
                else
                    folder = pluspath (cp);
            }
        }

        /* else, use the current folder */
        if (!folder)
            folder = add (getfolder (1), NULL);

        if (!(mp = folder_read (folder, 0)))
            adios (NULL, "unable to read folder %s", folder);
        for (ap = arguments; *ap; ap++) {
            cp = *ap;
            if (*cp != '+' && *cp != '@')
                if (!m_convert (mp, cp))
                    done (1);
        }
        free (folder);
        free_ctinfo (ct);

        /*
         * If there is more than one message to include, make this
         * a content of type "multipart/digest" and insert each message
         * as a subpart.  If there is only one message, then make this
         * a content of type "message/rfc822".
         */
        if (mp->numsel > 1) {
            /* we are forwarding multiple messages */
            if (get_ctinfo ("multipart/digest", ct, 0) == NOTOK)
                done (1);
            ct->c_type = CT_MULTIPART;
            ct->c_subtype = MULTI_DIGEST;

            if ((m = (struct multipart *) calloc (1, sizeof(*m))) == NULL)
                adios (NULL, "out of memory");
            ct->c_ctparams = (void *) m;
            pp = &m->mp_parts;

            for (msgnum = mp->lowsel; msgnum <= mp->hghsel; msgnum++) {
                if (is_selected(mp, msgnum)) {
                    struct part *part;
                    CT p;
                    CE pe;

                    if ((p = (CT) calloc (1, sizeof(*p))) == NULL)
                        adios (NULL, "out of memory");
                    init_decoded_content (p);
                    pe = &p->c_cefile;
                    if (get_ctinfo ("message/rfc822", p, 0) == NOTOK)
                        done (1);
                    p->c_type = CT_MESSAGE;
                    p->c_subtype = MESSAGE_RFC822;

                    snprintf (buffer, sizeof(buffer), "%s/%d", mp->foldpath, msgnum);
                    pe->ce_file = add (buffer, NULL);
                    if (listsw && stat (pe->ce_file, &st) != NOTOK)
                        p->c_end = (long) st.st_size;

                    if ((part = (struct part *) calloc (1, sizeof(*part))) == NULL)
                        adios (NULL, "out of memory");
                    *pp = part;
                    pp = &part->mp_next;
                    part->mp_part = p;
                }
            }
        } else {
            /* we are forwarding one message */
            if (get_ctinfo ("message/rfc822", ct, 0) == NOTOK)
                done (1);
            ct->c_type = CT_MESSAGE;
            ct->c_subtype = MESSAGE_RFC822;

            msgnum = mp->lowsel;
            snprintf (buffer, sizeof(buffer), "%s/%d", mp->foldpath, msgnum);
            ce->ce_file = add (buffer, NULL);
            if (listsw && stat (ce->ce_file, &st) != NOTOK)
                ct->c_end = (long) st.st_size;
        }

        folder_free (mp);       /* free folder/message structure */
        return OK;
    }

    /*
     * #end
     */
    if (!strcasecmp (ci->ci_type, "end")) {
        free_content (ct);
        *ctp = NULL;
        return DONE;
    }

    /*
     * #begin [ alternative | parallel ]
     */
    if (!strcasecmp (ci->ci_type, "begin")) {
        if (!ci->ci_magic) {
            vrsn = MULTI_MIXED;
            cp = SubMultiPart[vrsn - 1].kv_key;
        } else if (!strcasecmp (ci->ci_magic, "alternative")) {
            vrsn = MULTI_ALTERNATE;
            cp = SubMultiPart[vrsn - 1].kv_key;
        } else if (!strcasecmp (ci->ci_magic, "parallel")) {
            vrsn = MULTI_PARALLEL;
            cp = SubMultiPart[vrsn - 1].kv_key;
        } else if (uprf (ci->ci_magic, "digest")) {
            goto use_forw;
        } else {
            vrsn = MULTI_UNKNOWN;
            cp = ci->ci_magic;
        }

        free_ctinfo (ct);
        snprintf (buffer, sizeof(buffer), "multipart/%s", cp);
        if (get_ctinfo (buffer, ct, 0) == NOTOK)
            done (1);
        ct->c_type = CT_MULTIPART;
        ct->c_subtype = vrsn;

        if ((m = (struct multipart *) calloc (1, sizeof(*m))) == NULL)
            adios (NULL, "out of memory");
        ct->c_ctparams = (void *) m;

        pp = &m->mp_parts;
        while (fgetstr (buffer, sizeof(buffer) - 1, in)) {
            struct part *part;
            CT p;

            if (user_content (in, file, buffer, &p) == DONE) {
                if (!m->mp_parts)
                    adios (NULL, "empty \"#begin ... #end\" sequence");
                return OK;
            }
            if (!p)
                continue;

            if ((part = (struct part *) calloc (1, sizeof(*part))) == NULL)
                adios (NULL, "out of memory");
            *pp = part;
            pp = &part->mp_next;
            part->mp_part = p;
        }
        admonish (NULL, "premature end-of-file, missing #end");
        return OK;
    }

    /*
     * Unknown directive
     */
    adios (NULL, "unknown directive \"#%s\"", ci->ci_type);
    return NOTOK;       /* NOT REACHED */
}


static void
set_id (CT ct, int top)
{
    char contentid[BUFSIZ];
    static int partno;
    static time_t clock = 0;
    static char *msgfmt;

    if (clock == 0) {
        time (&clock);
        snprintf (contentid, sizeof(contentid), "%s\n", message_id (clock, 1));
        partno = 0;
        msgfmt = getcpy(contentid);
    }
    snprintf (contentid, sizeof(contentid), msgfmt, top ? 0 : ++partno);
    ct->c_id = getcpy (contentid);
}


/*
 * Fill out, or expand the various contents in the composition
 * draft.  Read-in any necessary files.  Parse and execute any
 * commands specified by profile composition strings.
 */

static int
compose_content (CT ct)
{
    CE ce = &ct->c_cefile;

    switch (ct->c_type) {
    case CT_MULTIPART:
    {
        int partnum;
        char *pp;
        char partnam[BUFSIZ];
        struct multipart *m = (struct multipart *) ct->c_ctparams;
        struct part *part;

        if (ct->c_partno) {
            snprintf (partnam, sizeof(partnam), "%s.", ct->c_partno);
            pp = partnam + strlen (partnam);
        } else {
            pp = partnam;
        }

        /* first, we call compose_content on all the subparts */
        for (part = m->mp_parts, partnum = 1; part; part = part->mp_next, partnum++) {
            CT p = part->mp_part;

            sprintf (pp, "%d", partnum);
            p->c_partno = add (partnam, NULL);
            if (compose_content (p) == NOTOK)
                return NOTOK;
        }

        /*
         * If the -rfc934mode switch is given, then check all
         * the subparts of a multipart/digest.  If they are all
         * message/rfc822, then mark this content and all
         * subparts with the rfc934 compatibility mode flag.
         */
        if (rfc934sw && ct->c_subtype == MULTI_DIGEST) {
            int is934 = 1;

            for (part = m->mp_parts; part; part = part->mp_next) {
                CT p = part->mp_part;

                if (p->c_subtype != MESSAGE_RFC822) {
                    is934 = 0;
                    break;
                }
            }
            ct->c_rfc934 = is934;
            for (part = m->mp_parts; part; part = part->mp_next) {
                CT p = part->mp_part;

                if ((p->c_rfc934 = is934))
                    p->c_end++;
            }
        }

        if (listsw) {
            ct->c_end = (partnum = strlen (prefix) + 2) + 2;
            if (ct->c_rfc934)
                ct->c_end += 1;

            for (part = m->mp_parts; part; part = part->mp_next)
                ct->c_end += part->mp_part->c_end + partnum;
        }
    }
    break;

    case CT_MESSAGE:
        /* Nothing to do for type message */
        break;

    /*
     * Discrete types (text/application/audio/image/video)
     */
    default:
        if (!ce->ce_file) {
            pid_t child_id;
            int i, xstdout, len, buflen;
            char *bp, **ap, *cp;
            char *vec[4], buffer[BUFSIZ];
            FILE *out;
            CI ci = &ct->c_ctinfo;
            char *tfile = NULL;

            if (!(cp = ci->ci_magic))
                adios (NULL, "internal error(5)");

            tfile = m_mktemp2(NULL, invo_name, NULL, NULL);
            if (tfile == NULL) {
                adios("mhbuildsbr", "unable to create temporary file");
            }
            ce->ce_file = add (tfile, NULL);
            ce->ce_unlink = 1;

            xstdout = 0;

            /* Get buffer ready to go */
            bp = buffer;
            bp[0] = '\0';
            buflen = sizeof(buffer);

            /*
             * Parse composition string into buffer
             */
            for ( ; *cp; cp++) {
                if (*cp == '%') {
                    switch (*++cp) {
                    case 'a':
                    {
                        /* insert parameters from directive */
                        char **ep;
                        char *s = "";

                        for (ap = ci->ci_attrs, ep = ci->ci_values; *ap; ap++, ep++) {
                            snprintf (bp, buflen, "%s%s=\"%s\"", s, *ap, *ep);
                            len = strlen (bp);
                            bp += len;
                            buflen -= len;
                            s = " ";
                        }
                    }
                    break;

                    case 'F':
                        /* %f, and stdout is not-redirected */
                        xstdout = 1;
                        /* and fall... */

                    case 'f':
                        /*
                         * insert temporary filename where
                         * content should be written
                         */
                        snprintf (bp, buflen, "%s", ce->ce_file);
                        break;

                    case 's':
                        /* insert content subtype */
                        strncpy (bp, ci->ci_subtype, buflen);
                        break;

                    case '%':
                        /* insert character % */
                        goto raw;

                    default:
                        *bp++ = *--cp;
                        *bp = '\0';
                        buflen--;
                        continue;
                    }
                    len = strlen (bp);
                    bp += len;
                    buflen -= len;
                } else {
raw:
                *bp++ = *cp;
                *bp = '\0';
                buflen--;
                }
            }

            if (verbosw)
                printf ("composing content %s/%s from command\n\t%s\n",
                        ci->ci_type, ci->ci_subtype, buffer);

            fflush (stdout);    /* not sure if need for -noverbose */

            vec[0] = "/bin/sh";
            vec[1] = "-c";
            vec[2] = buffer;
            vec[3] = NULL;

            if ((out = fopen (ce->ce_file, "w")) == NULL)
                adios (ce->ce_file, "unable to open for writing");

            for (i = 0; (child_id = fork()) == NOTOK && i > 5; i++)
                sleep (5);
            switch (child_id) {
            case NOTOK:
                adios ("fork", "unable to fork");
                /* NOTREACHED */

            case OK:
                if (!xstdout)
                    dup2 (fileno (out), 1);
                close (fileno (out));
                execvp ("/bin/sh", vec);
                fprintf (stderr, "unable to exec ");
                perror ("/bin/sh");
                _exit (-1);
                /* NOTREACHED */

            default:
                fclose (out);
                if (pidXwait(child_id, NULL))
                    done (1);
                break;
            }
        }

        /* Check size of file */
        if (listsw && ct->c_end == 0L) {
            struct stat st;

            if (stat (ce->ce_file, &st) != NOTOK)
                ct->c_end = (long) st.st_size;
        }
        break;
    }

    return OK;
}


/*
 * Scan the content.
 *
 *    1) choose a transfer encoding.
 *    2) check for clashes with multipart boundary string.
 *    3) for text content, figure out which character set is being used.
 *
 * If there is a clash with one of the contents and the multipart boundary,
 * this function will exit with NOTOK.  This will cause the scanning process
 * to be repeated with a different multipart boundary.  It is possible
 * (although highly unlikely) that this scan will be repeated multiple times.
 */

static int
scan_content (CT ct)
{
    int len;
    int check8bit = 0, contains8bit = 0;  /* check if contains 8bit data                */
    int checklinelen = 0, linelen = 0;    /* check for long lines                       */
    int checkboundary = 0, boundaryclash = 0; /* check if clashes with multipart boundary   */
    int checklinespace = 0, linespace = 0;  /* check if any line ends with space          */
    char *cp = NULL, buffer[BUFSIZ];
    struct text *t = NULL;
    FILE *in = NULL;
    CE ce = &ct->c_cefile;

    /*
     * handle multipart by scanning all subparts
     * and then checking their encoding.
     */
    if (ct->c_type == CT_MULTIPART) {
        struct multipart *m = (struct multipart *) ct->c_ctparams;
        struct part *part;

        /* initially mark the domain of enclosing multipart as 7bit */
        ct->c_encoding = CE_7BIT;

        for (part = m->mp_parts; part; part = part->mp_next) {
            CT p = part->mp_part;

            if (scan_content (p) == NOTOK)      /* choose encoding for subpart */
                return NOTOK;

            /* if necessary, enlarge encoding for enclosing multipart */
            if (p->c_encoding == CE_BINARY)
                ct->c_encoding = CE_BINARY;
            if (p->c_encoding == CE_8BIT && ct->c_encoding != CE_BINARY)
                ct->c_encoding = CE_8BIT;
        }

        return OK;
    }

    /*
     * Decide what to check while scanning this content.
     */
    switch (ct->c_type) {
    case CT_TEXT:
        check8bit = 1;
        checkboundary = 1;
        if (ct->c_subtype == TEXT_PLAIN) {
            checklinelen = 0;
            checklinespace = 0;
        } else {
            checklinelen = 1;
            checklinespace = 1;
        }
        break;

    case CT_APPLICATION:
        check8bit = 1;
        checklinelen = 1;
        checklinespace = 1;
        checkboundary = 1;
        break;

    case CT_MESSAGE:
        check8bit = 0;
        checklinelen = 0;
        checklinespace = 0;

        /* don't check anything for message/external */
        if (ct->c_subtype == MESSAGE_EXTERNAL)
            checkboundary = 0;
        else
            checkboundary = 1;
        break;

    case CT_AUDIO:
    case CT_IMAGE:
    case CT_VIDEO:
        /*
         * Don't check anything for these types,
         * since we are forcing use of base64.
         */
        check8bit = 0;
        checklinelen = 0;
        checklinespace = 0;
        checkboundary = 0;
        break;
    }

    /*
     * Scan the unencoded content
     */
    if (check8bit || checklinelen || checklinespace || checkboundary) {
        if ((in = fopen (ce->ce_file, "r")) == NULL)
            adios (ce->ce_file, "unable to open for reading");
        len = strlen (prefix);

        while (fgets (buffer, sizeof(buffer) - 1, in)) {
            /*
             * Check for 8bit data.
             */
            if (check8bit) {
                for (cp = buffer; *cp; cp++) {
                    if (!isascii ((unsigned char) *cp)) {
                        contains8bit = 1;
                        check8bit = 0;  /* no need to keep checking */
                    }
                }
            }

            /*
             * Check line length.
             */
            if (checklinelen && (strlen (buffer) > CPERLIN + 1)) {
                linelen = 1;
                checklinelen = 0;       /* no need to keep checking */
            }

            /*
             * Check if line ends with a space.
             */
            if (checklinespace && (cp = buffer + strlen (buffer) - 2) > buffer && isspace ((unsigned char) *cp)) {
                linespace = 1;
                checklinespace = 0;     /* no need to keep checking */
            }

            /*
             * Check if content contains a line that clashes
             * with our standard boundary for multipart messages.
             */
            if (checkboundary && buffer[0] == '-' && buffer[1] == '-') {
                for (cp = buffer + strlen (buffer) - 1; cp >= buffer; cp--)
                    if (!isspace ((unsigned char) *cp))
                        break;
                *++cp = '\0';
                if (!strncmp(buffer + 2, prefix, len) && isdigit((unsigned char) buffer[2 + len])) {
                    boundaryclash = 1;
                    checkboundary = 0;  /* no need to keep checking */
                }
            }
        }
        fclose (in);
    }

    /*
     * Decide which transfer encoding to use.
     */
    switch (ct->c_type) {
    case CT_TEXT:
        /*
         * If the text content didn't specify a character
         * set, we need to figure out which one was used.
         */
        t = (struct text *) ct->c_ctparams;
        if (t->tx_charset == CHARSET_UNSPECIFIED) {
            CI ci = &ct->c_ctinfo;
            char **ap, **ep;

            for (ap = ci->ci_attrs, ep = ci->ci_values; *ap; ap++, ep++)
                continue;

            if (contains8bit) {
                *ap = concat ("charset=", write_charset_8bit(), NULL);
            } else {
                *ap = add ("charset=us-ascii", NULL);
            }
            t->tx_charset = CHARSET_SPECIFIED;

            cp = strchr(*ap++, '=');
            *ap = NULL;
            *cp++ = '\0';
            *ep = cp;
        }

        if (contains8bit || linelen || linespace || checksw)
            ct->c_encoding = CE_QUOTED;
        else
            ct->c_encoding = CE_7BIT;
        break;

    case CT_APPLICATION:
        /* For application type, use base64, except when postscript */
        if (contains8bit || linelen || linespace || checksw)
            ct->c_encoding = (ct->c_subtype == APPLICATION_POSTSCRIPT)
                ? CE_QUOTED : CE_BASE64;
        else
            ct->c_encoding = CE_7BIT;
        break;

    case CT_MESSAGE:
        ct->c_encoding = CE_7BIT;
        break;

    case CT_AUDIO:
    case CT_IMAGE:
    case CT_VIDEO:
        /* For audio, image, and video contents, just use base64 */
        ct->c_encoding = CE_BASE64;
        break;
    }

    return (boundaryclash ? NOTOK : OK);
}


/*
 * Scan the content structures, and build header
 * fields that will need to be output into the
 * message.
 */

static int
build_headers (CT ct)
{
    int cc, mailbody, extbody, len;
    char **ap, **ep;
    char *np, *vp, buffer[BUFSIZ];
    CI ci = &ct->c_ctinfo;

    /*
     * If message is type multipart, then add the multipart
     * boundary to the list of attribute/value pairs.
     */
    if (ct->c_type == CT_MULTIPART) {
        char *cp;
        static int level = 0;   /* store nesting level */

        ap = ci->ci_attrs;
        ep = ci->ci_values;
        snprintf (buffer, sizeof(buffer), "boundary=%s%d", prefix, level++);
        cp = strchr(*ap++ = add (buffer, NULL), '=');
        *ap = NULL;
        *cp++ = '\0';
        *ep = cp;
    }

    /*
     * Skip the output of Content-Type, parameters, content
     * description and disposition, and Content-ID if the
     * content is of type "message" and the rfc934 compatibility
     * flag is set (which means we are inside multipart/digest
     * and the switch -rfc934mode was given).
     */
    if (ct->c_type == CT_MESSAGE && ct->c_rfc934)
        goto skip_headers;

    /*
     * output the content type and subtype
     */
    np = add (TYPE_FIELD, NULL);
    vp = concat (" ", ci->ci_type, "/", ci->ci_subtype, NULL);

    /* keep track of length of line */
    len = strlen (TYPE_FIELD) + strlen (ci->ci_type)
                + strlen (ci->ci_subtype) + 3;

    extbody = ct->c_type == CT_MESSAGE && ct->c_subtype == MESSAGE_EXTERNAL;
    mailbody = extbody && ((struct exbody *) ct->c_ctparams)->eb_body;

    /*
     * Append the attribute/value pairs to
     * the end of the Content-Type line.
     */
    for (ap = ci->ci_attrs, ep = ci->ci_values; *ap; ap++, ep++) {
        if (mailbody && !strcasecmp (*ap, "body"))
            continue;

        vp = add (";", vp);
        len++;

        /*
         * According to RFC 2017, if we have a URL longer than 40 characters
         * we have to break it across multiple lines
         */

        if (extbody && strcasecmp (*ap, "url") == 0) {
            char *value = *ep;

            /* 7 here refers to " url=\"\"" */
            if (len + 1 + (cc = (min(MAXURLTOKEN, strlen(value)) + 7)) >=
                                                                CPERLIN) {
                vp = add ("\n\t", vp);
                len = 8;
            } else {
                vp = add (" ", vp);
                len++;
            }

            vp = add ("url=\"", vp);
            len += 5;

            while (strlen(value) > MAXURLTOKEN) {
                strncpy(buffer, value, MAXURLTOKEN);
                buffer[MAXURLTOKEN] = '\0';
                vp = add (buffer, vp);
                vp = add ("\n\t", vp);
                value += MAXURLTOKEN;
                len = 8;
            }

            vp = add (value, vp);
            vp = add ("\"", vp);
            len += strlen(value) + 1;
            continue;
        }

        snprintf (buffer, sizeof(buffer), "%s=\"%s\"", *ap, *ep);
        if (len + 1 + (cc = strlen (buffer)) >= CPERLIN) {
            vp = add ("\n\t", vp);
            len = 8;
        } else {
            vp = add (" ", vp);
            len++;
        }
        vp = add (buffer, vp);
        len += cc;
    }

    /*
     * Append any RFC-822 comment to the end of
     * the Content-Type line.
     */
    if (ci->ci_comment) {
        snprintf (buffer, sizeof(buffer), "(%s)", ci->ci_comment);
        if (len + 1 + (cc = 2 + strlen (ci->ci_comment)) >= CPERLIN) {
            vp = add ("\n\t", vp);
            len = 8;
        } else {
            vp = add (" ", vp);
            len++;
        }
        vp = add (buffer, vp);
        len += cc;
    }
    vp = add ("\n", vp);
    add_header (ct, np, vp);

    /*
     * output the Content-ID, unless disabled by -nocontentid
     */
    if (contentidsw && ct->c_id) {
        np = add (ID_FIELD, NULL);
        vp = concat (" ", ct->c_id, NULL);
        add_header (ct, np, vp);
    }

    /*
     * output the Content-Description
     */
    if (ct->c_descr) {
        np = add (DESCR_FIELD, NULL);
        vp = concat (" ", ct->c_descr, NULL);
        add_header (ct, np, vp);
    }

    /*
     * output the Content-Disposition
     */
    if (ct->c_dispo) {
        np = add (DISPO_FIELD, NULL);
        vp = concat (" ", ct->c_dispo, NULL);
        add_header (ct, np, vp);
    }

skip_headers:
    /*
     * If this is the internal content structure for a
     * "message/external", then we are done with the
     * headers (since it has no body).
     */
    if (ct->c_ctexbody)
        return OK;

    /*
     * output the Content-MD5
     */
    if (checksw) {
        np = add (MD5_FIELD, NULL);
        vp = calculate_digest (ct, (ct->c_encoding == CE_QUOTED) ? 1 : 0);
        add_header (ct, np, vp);
    }

    /*
     * output the Content-Transfer-Encoding
     */
    switch (ct->c_encoding) {
    case CE_7BIT:
        /* Nothing to output */
        break;

    case CE_8BIT:
        if (ct->c_type == CT_MESSAGE)
            adios (NULL, "internal error, invalid encoding");

        np = add (ENCODING_FIELD, NULL);
        vp = concat (" ", "8bit", "\n", NULL);
        add_header (ct, np, vp);
        break;

    case CE_QUOTED:
        if (ct->c_type == CT_MESSAGE || ct->c_type == CT_MULTIPART)
            adios (NULL, "internal error, invalid encoding");

        np = add (ENCODING_FIELD, NULL);
        vp = concat (" ", "quoted-printable", "\n", NULL);
        add_header (ct, np, vp);
        break;

    case CE_BASE64:
        if (ct->c_type == CT_MESSAGE || ct->c_type == CT_MULTIPART)
            adios (NULL, "internal error, invalid encoding");

        np = add (ENCODING_FIELD, NULL);
        vp = concat (" ", "base64", "\n", NULL);
        add_header (ct, np, vp);
        break;

    case CE_BINARY:
        if (ct->c_type == CT_MESSAGE)
            adios (NULL, "internal error, invalid encoding");

        np = add (ENCODING_FIELD, NULL);
        vp = concat (" ", "binary", "\n", NULL);
        add_header (ct, np, vp);
        break;

    default:
        adios (NULL, "unknown transfer encoding in content");
        break;
    }

    /*
     * Additional content specific header processing
     */
    switch (ct->c_type) {
    case CT_MULTIPART:
    {
        struct multipart *m;
        struct part *part;

        m = (struct multipart *) ct->c_ctparams;
        for (part = m->mp_parts; part; part = part->mp_next) {
            CT p;

            p = part->mp_part;
            build_headers (p);
        }
    }
        break;

    case CT_MESSAGE:
        if (ct->c_subtype == MESSAGE_EXTERNAL) {
            struct exbody *e;

            e = (struct exbody *) ct->c_ctparams;
            build_headers (e->eb_content);
        }
        break;

    default:
        /* Nothing to do */
        break;
    }

    return OK;
}


static char nib2b64[0x40+1] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static char *
calculate_digest (CT ct, int asciiP)
{
    int cc;
    char buffer[BUFSIZ], *vp, *op;
    unsigned char *dp;
    unsigned char digest[16];
    unsigned char outbuf[25];
    MD5_CTX mdContext;
    CE ce = &ct->c_cefile;
    char *infilename = ce->ce_file ? ce->ce_file : ct->c_file;
    FILE *in;

    /* open content */
    if ((in = fopen (infilename, "r")) == NULL)
        adios (infilename, "unable to open for reading");

    /* Initialize md5 context */
    MD5Init (&mdContext);

    /* calculate md5 message digest */
    if (asciiP) {
        while (fgets (buffer, sizeof(buffer) - 1, in)) {
            char c, *cp;

            cp = buffer + strlen (buffer) - 1;
            if ((c = *cp) == '\n')
                *cp = '\0';

            MD5Update (&mdContext, (unsigned char *) buffer,
                       (unsigned int) strlen (buffer));

            if (c == '\n')
                MD5Update (&mdContext, (unsigned char *) "\r\n", 2);
        }
    } else {
        while ((cc = fread (buffer, sizeof(*buffer), sizeof(buffer), in)) > 0)
            MD5Update (&mdContext, (unsigned char *) buffer, (unsigned int) cc);
    }

    /* md5 finalization.  Write digest and zero md5 context */
    MD5Final (digest, &mdContext);

    /* close content */
    fclose (in);

    /* print debugging info */
    if (debugsw) {
        unsigned char *ep;

        fprintf (stderr, "MD5 digest=");
        for (ep = (dp = digest) + sizeof(digest) / sizeof(digest[0]);
                 dp < ep; dp++)
            fprintf (stderr, "%02x", *dp & 0xff);
        fprintf (stderr, "\n");
    }

    /* encode the digest using base64 */
    for (dp = digest, op = (char *) outbuf,
                                cc = sizeof(digest) / sizeof(digest[0]);
                cc > 0; cc -= 3, op += 4) {
        unsigned long bits;
        char *bp;

        bits = (*dp++ & 0xff) << 16;
        if (cc > 1) {
            bits |= (*dp++ & 0xff) << 8;
            if (cc > 2)
                bits |= *dp++ & 0xff;
        }

        for (bp = op + 4; bp > op; bits >>= 6)
            *--bp = nib2b64[bits & 0x3f];
        if (cc < 3) {
            *(op + 3) = '=';
            if (cc < 2)
                *(op + 2) = '=';
        }
    }

    /* null terminate string */
    outbuf[24] = '\0';

    /* now make copy and return string */
    vp = concat (" ", outbuf, "\n", NULL);
    return vp;
}