Initial import of Sylpheed (GTK2 version).

git-svn-id: svn://sylpheed.sraoss.jp/sylpheed/trunk@1 ee746299-78ed-0310-b773-934348b2243d

1 files changed, 1395 insertions, 0 deletions

diff --git a/src/rfc2015.c b/src/rfc2015.c
new file mode 100644
index 00000000..9ef38a24
--- /dev/null
+++ b/src/rfc2015.c
@@ -0,0 +1,1395 @@
+/*
+ * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
+ * Copyright (C) 2001 Werner Koch (dd9jn)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#if USE_GPGME
+
+#include "defs.h"
+
+#include <glib.h>
+#include <stdio.h>
+#include <string.h>
+#include <locale.h>
+#include <ctype.h>
+
+#include <gpgme.h>
+
+#include "intl.h"
+#include "procmime.h"
+#include "procheader.h"
+#include "base64.h"
+#include "uuencode.h"
+#include "unmime.h"
+#include "codeconv.h"
+#include "utils.h"
+#include "prefs_common.h"
+#include "passphrase.h"
+#include "select-keys.h"
+#include "sigstatus.h"
+#include "rfc2015.h"
+
+#define DIM(v)     (sizeof(v)/sizeof((v)[0]))
+
+static char *content_names[] = {
+    "Content-Type",
+    "Content-Disposition",
+    "Content-Transfer-Encoding",
+    NULL
+};
+
+static char *mime_version_name[] = {
+    "Mime-Version",
+    NULL
+};
+
+#if 0
+static void dump_mimeinfo (const char *text, MimeInfo *x)
+{
+    debug_print ("MimeInfo[%s] %p  level=%d\n",
+               text, x, x? x->level:0 );
+    if (!x)
+        return;
+
+    debug_print ("      enc=`%s' enc_type=%d mime_type=%d\n",
+               x->encoding, x->encoding_type, x->mime_type );
+    debug_print ("      cont_type=`%s' cs=`%s' name=`%s' bnd=`%s'\n",
+               x->content_type, x->charset, x->name, x->boundary );
+    debug_print ("      cont_disp=`%s' fname=`%s' fpos=%ld size=%u, lvl=%d\n",
+               x->content_disposition, x->filename, x->fpos, x->size,
+               x->level );
+    dump_mimeinfo (".main", x->main );
+    dump_mimeinfo (".sub", x->sub );
+    dump_mimeinfo (".next", x->next );
+    debug_print ("MimeInfo[.parent] %p\n", x ); 
+    dump_mimeinfo (".children", x->children );
+    dump_mimeinfo (".plaintext", x->plaintext );
+}
+
+static void dump_part ( MimeInfo *mimeinfo, FILE *fp )
+{
+    unsigned int size = mimeinfo->size;
+    int c;
+
+    if (fseek (fp, mimeinfo->fpos, SEEK_SET)) {
+        debug_print ("dump_part: fseek error\n");
+        return;
+    }
+
+    debug_print ("--- begin dump_part ----\n");
+    while (size-- && (c = getc (fp)) != EOF) 
+        putc (c, stderr);
+    if (ferror (fp))
+        debug_print ("dump_part: read error\n");
+    debug_print ("--- end dump_part ----\n");
+}
+#endif
+
+void
+rfc2015_disable_all (void)
+{
+    /* FIXME: set a flag, so that we don't bother the user with failed
+     * gpgme messages */
+}
+
+
+void
+rfc2015_secure_remove (const char *fname)
+{
+    if (!fname)
+        return;
+    /* fixme: overwrite the file first */
+    remove (fname);
+}
+
+
+static const gchar *
+sig_status_to_string (GpgmeSigStat status)
+{
+    const gchar *result;
+
+    switch (status) {
+      case GPGME_SIG_STAT_NONE:
+        result = _("Oops: Signature not verified");
+        break;
+      case GPGME_SIG_STAT_NOSIG:
+        result = _("No signature found");
+        break;
+      case GPGME_SIG_STAT_GOOD:
+        result = _("Good signature");
+        break;
+      case GPGME_SIG_STAT_BAD:
+        result = _("BAD signature");
+        break;
+      case GPGME_SIG_STAT_NOKEY:
+        result = _("No public key to verify the signature");
+        break;
+      case GPGME_SIG_STAT_ERROR:
+        result = _("Error verifying the signature");
+        break;
+      case GPGME_SIG_STAT_DIFF:
+        result = _("Different results for signatures");
+        break;
+      default:
+	result = _("Error: Unknown status");
+	break;
+    }
+
+    return result;
+}
+
+static const gchar *
+sig_status_with_name (GpgmeSigStat status)
+{
+    const gchar *result;
+
+    switch (status) {
+      case GPGME_SIG_STAT_NONE:
+        result = _("Oops: Signature not verified");
+        break;
+      case GPGME_SIG_STAT_NOSIG:
+        result = _("No signature found");
+        break;
+      case GPGME_SIG_STAT_GOOD:
+        result = _("Good signature from \"%s\"");
+        break;
+      case GPGME_SIG_STAT_BAD:
+        result = _("BAD signature from \"%s\"");
+        break;
+      case GPGME_SIG_STAT_NOKEY:
+        result = _("No public key to verify the signature");
+        break;
+      case GPGME_SIG_STAT_ERROR:
+        result = _("Error verifying the signature");
+        break;
+      case GPGME_SIG_STAT_DIFF:
+        result = _("Different results for signatures");
+        break;
+      default:
+	result = _("Error: Unknown status");
+	break;
+    }
+
+    return result;
+}
+
+static void
+sig_status_for_key(GString *str, GpgmeCtx ctx, GpgmeSigStat status, 
+		   GpgmeKey key, const gchar *fpr)
+{
+	gint idx = 0;
+	const char *uid;
+
+	uid = gpgme_key_get_string_attr (key, GPGME_ATTR_USERID, NULL, idx);
+	if (uid == NULL) {
+		g_string_sprintfa (str, "%s\n",
+				   sig_status_to_string (status));
+		if ((fpr != NULL) && (*fpr != '\0'))
+			g_string_sprintfa (str, "Key fingerprint: %s\n", fpr);
+		g_string_append (str, _("Cannot find user ID for this key."));
+		return;
+	}
+	g_string_sprintfa (str, sig_status_with_name (status), uid);
+	g_string_append (str, "\n");
+
+	while (1) {
+		uid = gpgme_key_get_string_attr (key, GPGME_ATTR_USERID,
+						 NULL, ++idx);
+		if (uid == NULL)
+			break;
+		g_string_sprintfa (str, _("                aka \"%s\"\n"),
+				   uid);
+	}
+}
+
+static gchar *
+sig_status_full (GpgmeCtx ctx)
+{
+	GString *str;
+	gint sig_idx = 0;
+	GpgmeError err;
+	GpgmeSigStat status;
+	GpgmeKey key;
+	const char *fpr;
+	time_t created;
+	struct tm *ctime_val;
+	char ctime_str[80];
+	gchar *retval;
+
+	str = g_string_new ("");
+
+	fpr = gpgme_get_sig_status (ctx, sig_idx, &status, &created);
+	while (fpr != NULL) {
+		if (created != 0) {
+			ctime_val = localtime (&created);
+			strftime (ctime_str, sizeof (ctime_str), "%c", 
+				  ctime_val);
+			g_string_sprintfa (str,
+					   _("Signature made at %s\n"),
+					   ctime_str);
+		}
+		err = gpgme_get_sig_key (ctx, sig_idx, &key);
+		if (err != 0) {
+			g_string_sprintfa (str, "%s\n",
+					   sig_status_to_string (status));
+			if ((fpr != NULL) && (*fpr != '\0'))
+				g_string_sprintfa (str, 
+						   _("Key fingerprint: %s\n"),
+						   fpr);
+		} else {
+			sig_status_for_key (str, ctx, status, key, fpr);
+			gpgme_key_unref (key);
+		}
+		g_string_append (str, "\n\n");
+
+		fpr = gpgme_get_sig_status (ctx, ++sig_idx, &status, &created);
+	}
+
+	retval = str->str;
+	g_string_free (str, FALSE);
+	return retval;
+}
+
+static void check_signature (MimeInfo *mimeinfo, MimeInfo *partinfo, FILE *fp)
+{
+    GpgmeCtx ctx = NULL;
+    GpgmeError err;
+    GpgmeData sig = NULL, text = NULL;
+    GpgmeSigStat status = GPGME_SIG_STAT_NONE;
+    GpgmegtkSigStatus statuswindow = NULL;
+    const char *result = NULL;
+    gchar *tmp_file;
+    gint n_exclude_chars = 0;
+
+    if (prefs_common.gpg_signature_popup)
+	statuswindow = gpgmegtk_sig_status_create ();
+
+    err = gpgme_new (&ctx);
+    if (err) {
+	debug_print ("gpgme_new failed: %s\n", gpgme_strerror (err));
+	goto leave;
+    }
+
+    /* don't include the last empty line.
+       It does not belong to the signed text */
+    if (mimeinfo->children->size > 0) {
+	if (fseek(fp, mimeinfo->children->fpos + mimeinfo->children->size - 1,
+		  SEEK_SET) < 0) {
+	    perror("fseek");
+	    goto leave;
+	}
+	if (fgetc(fp) == '\n') {
+	    n_exclude_chars++;
+	    if (mimeinfo->children->size > 1) {
+		if (fseek(fp, mimeinfo->children->fpos + mimeinfo->children->size - 2,
+			  SEEK_SET) < 0) {
+		    perror("fseek");
+		    goto leave;
+		}
+		if (fgetc(fp) == '\r')
+		    n_exclude_chars++;
+	    }
+	}
+    }
+
+    /* canonicalize the file part. */
+    tmp_file = get_tmp_file();
+    if (copy_file_part(fp, mimeinfo->children->fpos,
+		       mimeinfo->children->size - n_exclude_chars,
+		       tmp_file) < 0) {
+	g_free(tmp_file);
+	goto leave;
+    }
+    if (canonicalize_file_replace(tmp_file) < 0) {
+	unlink(tmp_file);
+	g_free(tmp_file);
+	goto leave;
+    }
+
+    err = gpgme_data_new_from_file(&text, tmp_file, 1);
+
+    unlink(tmp_file);
+    g_free(tmp_file);
+
+    if (!err)
+	err = gpgme_data_new_from_filepart (&sig, NULL, fp,
+					    partinfo->fpos, partinfo->size);
+    if (err) {
+        debug_print ("gpgme_data_new_from_filepart failed: %s\n",
+		   gpgme_strerror (err));
+        goto leave;
+    }
+
+    err = gpgme_op_verify (ctx, sig, text, &status);
+    if (err)  {
+        debug_print ("gpgme_op_verify failed: %s\n", gpgme_strerror (err));
+        goto leave;
+    }
+
+    /* FIXME: check what the heck this sig_status_full stuff is.
+     * it should better go into sigstatus.c */
+    g_free (partinfo->sigstatus_full);
+    partinfo->sigstatus_full = sig_status_full (ctx);
+
+leave:
+    result = gpgmegtk_sig_status_to_string(status);
+    debug_print("verification status: %s\n", result);
+    if (prefs_common.gpg_signature_popup)
+	gpgmegtk_sig_status_update (statuswindow, ctx);
+
+    g_free (partinfo->sigstatus);
+    partinfo->sigstatus = g_strdup (result);
+
+    gpgme_data_release (sig);
+    gpgme_data_release (text);
+    gpgme_release (ctx);
+    if (prefs_common.gpg_signature_popup)
+	gpgmegtk_sig_status_destroy (statuswindow);
+}
+
+/*
+ * Copy a gpgme data object to a temporary file and
+ * return this filename 
+ */
+#if 0
+static char *
+copy_gpgmedata_to_temp (GpgmeData data, guint *length)
+{
+    static int id;
+    char *tmp;
+    FILE *fp;
+    char buf[100];
+    size_t nread;
+    GpgmeError err;
+    
+    tmp = g_strdup_printf("%s%cgpgtmp.%08x",
+                          get_mime_tmp_dir(), G_DIR_SEPARATOR, ++id );
+
+    if ((fp = fopen(tmp, "wb")) == NULL) {
+        FILE_OP_ERROR(tmp, "fopen");
+        g_free(tmp);
+        return NULL;
+    }
+
+    err = gpgme_data_rewind ( data );
+    if (err)
+        debug_print ("gpgme_data_rewind failed: %s\n", gpgme_strerror (err));
+
+    while (!(err = gpgme_data_read (data, buf, 100, &nread))) {
+        fwrite ( buf, nread, 1, fp );
+    }
+
+    if (err != GPGME_EOF)
+        debug_print ("gpgme_data_read failed: %s\n", gpgme_strerror (err));
+
+    fclose (fp);
+    *length = nread;
+
+    return tmp;
+}
+#endif
+
+static GpgmeData
+pgp_decrypt (MimeInfo *partinfo, FILE *fp)
+{
+    GpgmeCtx ctx = NULL;
+    GpgmeError err;
+    GpgmeData cipher = NULL, plain = NULL;
+    struct passphrase_cb_info_s info;
+
+    memset (&info, 0, sizeof info);
+
+    err = gpgme_new (&ctx);
+    if (err) {
+        debug_print ("gpgme_new failed: %s\n", gpgme_strerror (err));
+        goto leave;
+    }
+
+    err = gpgme_data_new_from_filepart (&cipher, NULL, fp,
+					partinfo->fpos, partinfo->size);
+    if (err) {
+        debug_print ("gpgme_data_new_from_filepart failed: %s\n",
+                     gpgme_strerror (err));
+        goto leave;
+    }
+
+    err = gpgme_data_new (&plain);
+    if (err) {
+        debug_print ("gpgme_new failed: %s\n", gpgme_strerror (err));
+        goto leave;
+    }
+
+    if (!getenv("GPG_AGENT_INFO")) {
+        info.c = ctx;
+        gpgme_set_passphrase_cb (ctx, gpgmegtk_passphrase_cb, &info);
+    } 
+
+    err = gpgme_op_decrypt (ctx, cipher, plain);
+
+leave:
+    gpgme_data_release (cipher);
+    if (err) {
+        gpgmegtk_free_passphrase();
+        debug_print ("decryption failed: %s\n", gpgme_strerror (err));
+        gpgme_data_release (plain);
+        plain = NULL;
+    }
+    else
+        debug_print ("** decryption succeeded\n");
+
+    gpgme_release (ctx);
+    return plain;
+}
+
+MimeInfo * rfc2015_find_signature (MimeInfo *mimeinfo)
+{
+    MimeInfo *partinfo;
+    int n = 0;
+
+    if (!mimeinfo)
+        return NULL;
+    if (g_strcasecmp (mimeinfo->content_type, "multipart/signed"))
+        return NULL;
+
+    debug_print ("** multipart/signed encountered\n");
+
+    /* check that we have at least 2 parts of the correct type */
+    for (partinfo = mimeinfo->children;
+         partinfo != NULL; partinfo = partinfo->next) {
+        if (++n > 1  && !g_strcasecmp (partinfo->content_type,
+				       "application/pgp-signature"))
+            break;
+    }
+
+    return partinfo;
+}
+
+gboolean rfc2015_has_signature (MimeInfo *mimeinfo)
+{
+    return rfc2015_find_signature (mimeinfo) != NULL;
+}
+
+void rfc2015_check_signature (MimeInfo *mimeinfo, FILE *fp)
+{
+    MimeInfo *partinfo;
+
+    partinfo = rfc2015_find_signature (mimeinfo);
+    if (!partinfo)
+        return;
+
+#if 0
+    g_message ("** yep, it is a pgp signature");
+    dump_mimeinfo ("gpg-signature", partinfo );
+    dump_part (partinfo, fp );
+    dump_mimeinfo ("signed text", mimeinfo->children );
+    dump_part (mimeinfo->children, fp);
+#endif
+
+    check_signature (mimeinfo, partinfo, fp);
+}
+
+int rfc2015_is_encrypted (MimeInfo *mimeinfo)
+{
+    if (!mimeinfo || mimeinfo->mime_type != MIME_MULTIPART)
+        return 0;
+    if (g_strcasecmp (mimeinfo->content_type, "multipart/encrypted"))
+        return 0;
+    /* fixme: we should check the protocol parameter */
+    return 1;
+}
+
+gboolean rfc2015_msg_is_encrypted (const gchar *file)
+{
+	FILE *fp;
+	MimeInfo *mimeinfo;
+	int ret;
+
+	if ((fp = fopen(file, "rb")) == NULL)
+		return FALSE;
+
+	mimeinfo = procmime_scan_mime_header(fp);
+	if(!mimeinfo) {
+		fclose(fp);
+		return FALSE;
+	}
+
+	ret = rfc2015_is_encrypted(mimeinfo);
+	procmime_mimeinfo_free_all(mimeinfo);
+	return ret != 0 ? TRUE : FALSE;
+}
+
+static int
+name_cmp(const char *a, const char *b)
+{
+    for( ; *a && *b; a++, b++) {
+        if(*a != *b
+           && toupper(*(unsigned char *)a) != toupper(*(unsigned char *)b))
+            return 1;
+    }
+
+    return *a != *b;
+}
+
+static int
+headerp(char *p, char **names)
+{
+    int i, c;
+    char *p2;
+
+    p2 = strchr(p, ':');
+    if(!p2 || p == p2) {
+        return 0;
+    }
+    if(p2[-1] == ' ' || p2[-1] == '\t') {
+        return 0;
+    }
+
+    if(!names[0])
+        return 1;  
+
+    c = *p2;
+    *p2 = 0;
+    for(i = 0 ; names[i] != NULL; i++) {
+        if(!name_cmp (names[i], p))
+            break;
+    }
+    *p2 = c;
+
+    return names[i] != NULL;
+}
+
+
+#define DECRYPTION_ABORT() \
+{ \
+    procmime_mimeinfo_free_all(tmpinfo); \
+    msginfo->decryption_failed = 1; \
+    return; \
+}
+
+void rfc2015_decrypt_message (MsgInfo *msginfo, MimeInfo *mimeinfo, FILE *fp)
+{
+    static int id;
+    MimeInfo *tmpinfo, *partinfo;
+    int ver_ok = 0;
+    char *fname;
+    GpgmeData plain;
+    FILE *dstfp;
+    size_t nread;
+    char buf[BUFFSIZE];
+    int in_cline;
+    GpgmeError err;
+
+    g_return_if_fail (msginfo != NULL);
+    g_return_if_fail (mimeinfo != NULL);
+    g_return_if_fail (fp != NULL);
+    g_return_if_fail (mimeinfo->mime_type == MIME_MULTIPART);
+
+    debug_print ("** decrypting multipart/encrypted message\n");
+
+    /* skip headers */
+    if (fseek(fp, mimeinfo->fpos, SEEK_SET) < 0)
+        perror("fseek");
+    tmpinfo = procmime_scan_mime_header(fp);
+    if (!tmpinfo || tmpinfo->mime_type != MIME_MULTIPART) {
+        DECRYPTION_ABORT();
+    }
+
+    procmime_scan_multipart_message(tmpinfo, fp);
+
+    /* check that we have the 2 parts */
+    partinfo = tmpinfo->children;
+    if (!partinfo || !partinfo->next) {
+        DECRYPTION_ABORT();
+    }
+    if (!g_strcasecmp (partinfo->content_type, "application/pgp-encrypted")) {
+        /* Fixme: check that the version is 1 */
+        ver_ok = 1;
+    }
+    partinfo = partinfo->next;
+    if (ver_ok &&
+        !g_strcasecmp (partinfo->content_type, "application/octet-stream")) {
+        if (partinfo->next)
+            g_warning ("oops: pgp_encrypted with more than 2 parts");
+    }
+    else {
+        DECRYPTION_ABORT();
+    }
+
+    debug_print ("** yep, it is pgp encrypted\n");
+
+    plain = pgp_decrypt (partinfo, fp);
+    if (!plain) {
+        DECRYPTION_ABORT();
+    }
+
+    fname = g_strdup_printf("%s%cplaintext.%08x",
+			    get_mime_tmp_dir(), G_DIR_SEPARATOR, ++id);
+
+    if ((dstfp = fopen(fname, "wb")) == NULL) {
+        FILE_OP_ERROR(fname, "fopen");
+        g_free(fname);
+        DECRYPTION_ABORT();
+    }
+
+    /* write the orginal header to the new file */
+    if (fseek(fp, tmpinfo->fpos, SEEK_SET) < 0)
+        perror("fseek");
+
+    in_cline = 0;
+    while (fgets(buf, sizeof(buf), fp)) {
+        if (headerp (buf, content_names)) {
+            in_cline = 1;
+            continue;
+        }
+        if (in_cline) {
+            if (buf[0] == ' ' || buf[0] == '\t')
+                continue;
+            in_cline = 0;
+        }
+        if (buf[0] == '\r' || buf[0] == '\n')
+            break;
+        fputs (buf, dstfp);
+    }
+
+    err = gpgme_data_rewind (plain);
+    if (err)
+        debug_print ("gpgme_data_rewind failed: %s\n", gpgme_strerror (err));
+
+    while (!(err = gpgme_data_read (plain, buf, sizeof(buf), &nread))) {
+        fwrite (buf, nread, 1, dstfp);
+    }
+
+    if (err != GPGME_EOF) {
+        debug_print ("gpgme_data_read failed: %s\n", gpgme_strerror (err));
+    }
+
+    fclose (dstfp);
+    procmime_mimeinfo_free_all(tmpinfo);
+
+    msginfo->plaintext_file = fname;
+    msginfo->decryption_failed = 0;
+}
+
+#undef DECRYPTION_ABORT
+
+
+/*
+ * plain contains an entire mime object.
+ * Encrypt it and return an GpgmeData object with the encrypted version of
+ * the file or NULL in case of error.
+ */
+static GpgmeData
+pgp_encrypt ( GpgmeData plain, GpgmeRecipients rset )
+{
+    GpgmeCtx ctx = NULL;
+    GpgmeError err;
+    GpgmeData cipher = NULL;
+
+    err = gpgme_new (&ctx);
+    if (!err)
+	err = gpgme_data_new (&cipher);
+    if (!err) {
+        gpgme_set_armor (ctx, 1);
+	err = gpgme_op_encrypt (ctx, rset, plain, cipher);
+    }
+
+    if (err) {
+        debug_print ("encryption failed: %s\n", gpgme_strerror (err));
+        gpgme_data_release (cipher);
+        cipher = NULL;
+    }
+    else {
+        debug_print ("** encryption succeeded\n");
+    }
+
+    gpgme_release (ctx);
+    return cipher;
+}
+
+/*
+ * Create and return a list of keys matching a key id
+ */
+
+GSList *rfc2015_create_signers_list (const char *keyid)
+{
+	GSList *key_list = NULL;
+	GpgmeCtx list_ctx = NULL;
+	GSList *p;
+	GpgmeError err;
+	GpgmeKey key;
+
+	err = gpgme_new (&list_ctx);
+	if (err)
+		goto leave;
+	err = gpgme_op_keylist_start (list_ctx, keyid, 1);
+	if (err)
+		goto leave;
+	while ( !(err = gpgme_op_keylist_next (list_ctx, &key)) ) {
+		key_list = g_slist_append (key_list, key);
+	}
+	if (err != GPGME_EOF)
+		goto leave;
+	err = 0;
+	if (key_list == NULL) {
+		debug_print ("no keys found for keyid \"%s\"\n", keyid);
+	}
+
+leave:
+	if (err) {
+		debug_print ("rfc2015_create_signers_list failed: %s\n", gpgme_strerror (err));
+		for (p = key_list; p != NULL; p = p->next)
+			gpgme_key_unref ((GpgmeKey) p->data);
+		g_slist_free (key_list);
+	}
+	if (list_ctx)
+		gpgme_release (list_ctx);
+	return err ? NULL : key_list;
+}
+
+/*
+ * Encrypt the file by extracting all recipients and finding the
+ * encryption keys for all of them.  The file content is then replaced
+ * by the encrypted one.  */
+int
+rfc2015_encrypt (const char *file, GSList *recp_list, gboolean ascii_armored)
+{
+    FILE *fp = NULL;
+    char buf[BUFFSIZE];
+    int i, clineidx, saved_last;
+    char *clines[3] = {NULL};
+    GpgmeError err;
+    GpgmeData header = NULL;
+    GpgmeData plain = NULL;
+    GpgmeData cipher = NULL;
+    GpgmeRecipients rset = NULL;
+    size_t nread;
+    int mime_version_seen = 0;
+    char *boundary;
+
+    boundary = generate_mime_boundary ("Encrypt");
+
+    /* Create the list of recipients */
+    rset = gpgmegtk_recipient_selection (recp_list);
+    if (!rset) {
+        debug_print ("error creating recipient list\n" );
+        goto failure;
+    }
+
+    /* Open the source file */
+    if ((fp = fopen(file, "rb")) == NULL) {
+        FILE_OP_ERROR(file, "fopen");
+        goto failure;
+    }
+
+    err = gpgme_data_new (&header);
+    if (!err)
+	err = gpgme_data_new (&plain);
+    if (err) {
+        debug_print ("gpgme_data_new failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    /* get the content header lines from the source */
+    clineidx = 0;
+    saved_last = 0;
+    while (!err && fgets(buf, sizeof(buf), fp)) {
+        /* fixme: check for overlong lines */
+        if (headerp (buf, content_names)) {
+            if (clineidx >= DIM (clines)) {
+                debug_print ("rfc2015_encrypt: too many content lines\n");
+                goto failure;
+            }
+            clines[clineidx++] = g_strdup (buf);
+            saved_last = 1;
+            continue;
+        }
+        if (saved_last) {
+            if (*buf == ' ' || *buf == '\t') {
+                char *last = clines[clineidx - 1];
+                clines[clineidx - 1] = g_strconcat (last, buf, NULL);
+                g_free (last);
+                continue;
+            }
+            saved_last = 0;
+        }
+
+        if (headerp (buf, mime_version_name)) 
+            mime_version_seen = 1;
+
+        if (buf[0] == '\r' || buf[0] == '\n')
+            break;
+        err = gpgme_data_write (header, buf, strlen (buf));
+    }
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fgets");
+        goto failure;
+    }
+
+    /* write them to the temp data and add the rest of the message */
+    for (i = 0; !err && i < clineidx; i++) {
+        debug_print ("%% %s:%d: cline=`%s'", __FILE__ ,__LINE__, clines[i]);
+        err = gpgme_data_write (plain, clines[i], strlen (clines[i]));
+    }
+    if (!err)
+        err = gpgme_data_write (plain, "\r\n", 2);
+    while (!err && fgets(buf, sizeof(buf), fp)) {
+        err = gpgme_data_write (plain, buf, strlen (buf));
+    }
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fgets");
+        goto failure;
+    }
+    if (err) {
+        debug_print ("gpgme_data_write failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    cipher = pgp_encrypt (plain, rset);
+    gpgme_data_release (plain); plain = NULL;
+    gpgme_recipients_release (rset); rset = NULL;
+    if (!cipher)
+        goto failure;
+
+    /* we have the encrypted message available in cipher and now we
+     * are going to rewrite the source file. To be sure that file has
+     * been truncated we use an approach which should work everywhere:
+     * close the file and then reopen it for writing. It is important
+     * that this works, otherwise it may happen that parts of the
+     * plaintext are still in the file (The encrypted stuff is, due to
+     * compression, usually shorter than the plaintext). 
+     * 
+     * Yes, there is a race condition here, but everyone, who is so
+     * stupid to store the temp file with the plaintext in a public
+     * directory has to live with this anyway. */
+    if (fclose (fp)) {
+        FILE_OP_ERROR(file, "fclose");
+        goto failure;
+    }
+    if ((fp = fopen(file, "wb")) == NULL) {
+        FILE_OP_ERROR(file, "fopen");
+        goto failure;
+    }
+
+    /* Write the header, append new content lines, part 1 and part 2 header */
+    err = gpgme_data_rewind (header);
+    if (err) {
+        debug_print ("gpgme_data_rewind failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+    while (!(err = gpgme_data_read (header, buf, BUFFSIZE, &nread))) {
+        fwrite (buf, nread, 1, fp);
+    }
+    if (err != GPGME_EOF) {
+        debug_print ("gpgme_data_read failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fwrite");
+        goto failure;
+    }
+    gpgme_data_release (header); header = NULL;
+    
+    if (!mime_version_seen) 
+        fputs ("MIME-Version: 1\r\n", fp);
+
+    if (ascii_armored) {
+        fprintf(fp, 
+            "Content-Type: text/plain; charset=US-ASCII\r\n"
+            "Content-Transfer-Encoding: 7bit\r\n"  
+            "\r\n");
+    } else {
+        fprintf (fp,
+	        "Content-Type: multipart/encrypted;"
+	        " protocol=\"application/pgp-encrypted\";\r\n"
+	        " boundary=\"%s\"\r\n"
+	        "\r\n"
+	        "--%s\r\n"
+	        "Content-Type: application/pgp-encrypted\r\n"
+	        "\r\n"
+	        "Version: 1\r\n"
+	        "\r\n"
+	        "--%s\r\n"
+	        "Content-Type: application/octet-stream\r\n"
+	        "\r\n",
+	        boundary, boundary, boundary);
+    }
+
+    /* append the encrypted stuff */
+    err = gpgme_data_rewind (cipher);
+    if (err) {
+        debug_print ("** gpgme_data_rewind on cipher failed: %s\n",
+                   gpgme_strerror (err));
+        goto failure;
+    }
+
+    while (!(err = gpgme_data_read (cipher, buf, BUFFSIZE, &nread))) {
+        fwrite (buf, nread, 1, fp);
+    }
+    if (err != GPGME_EOF) {
+        debug_print ("** gpgme_data_read failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    /* and the final boundary */
+    if (!ascii_armored) {
+        fprintf (fp,
+		 "\r\n"
+		 "--%s--\r\n",
+	         boundary);
+    }
+    fflush (fp);
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fwrite");
+        goto failure;
+    }
+    fclose (fp);
+    gpgme_data_release (cipher);
+    return 0;
+
+failure:
+    if (fp) 
+        fclose (fp);
+    gpgme_data_release (header);
+    gpgme_data_release (plain);
+    gpgme_data_release (cipher);
+    gpgme_recipients_release (rset);
+    g_free (boundary);
+    return -1; /* error */
+}
+
+/* 
+ * plain contains an entire mime object.  Sign it and return an
+ * GpgmeData object with the signature of it or NULL in case of error.
+ * r_siginfo returns an XML object with information about the signature.
+ */
+static GpgmeData
+pgp_sign (GpgmeData plain, GSList *key_list, gboolean clearsign,
+	  char **r_siginfo)
+{
+    GSList *p;
+    GpgmeCtx ctx = NULL;
+    GpgmeError err;
+    GpgmeData sig = NULL;
+    struct passphrase_cb_info_s info;
+
+    *r_siginfo = NULL;
+    memset (&info, 0, sizeof info);
+
+    err = gpgme_new (&ctx);
+    if (err)
+        goto leave;
+    err = gpgme_data_new (&sig);
+    if (err)
+        goto leave;
+
+    if (!getenv("GPG_AGENT_INFO")) {
+        info.c = ctx;
+        gpgme_set_passphrase_cb (ctx, gpgmegtk_passphrase_cb, &info);
+    }
+    gpgme_set_textmode (ctx, 1);
+    gpgme_set_armor (ctx, 1);
+    gpgme_signers_clear (ctx);
+    for (p = key_list; p != NULL; p = p->next) {
+	err = gpgme_signers_add (ctx, (GpgmeKey) p->data);
+	if (err)
+	    goto leave;
+    }
+    for (p = key_list; p != NULL; p = p->next)
+	gpgme_key_unref ((GpgmeKey) p->data);
+    g_slist_free (key_list);
+
+    if (err)
+	goto leave;
+    err = gpgme_op_sign
+	(ctx, plain, sig,
+	 clearsign ? GPGME_SIG_MODE_CLEAR : GPGME_SIG_MODE_DETACH);
+    if (!err)
+        *r_siginfo = gpgme_get_op_info (ctx, 0);
+
+leave:
+    if (err) {
+        gpgmegtk_free_passphrase();
+        debug_print ("signing failed: %s\n", gpgme_strerror (err));
+        gpgme_data_release (sig);
+        sig = NULL;
+    }
+    else {
+        debug_print ("signing succeeded\n");
+    }
+
+    gpgme_release (ctx);
+    return sig;
+}
+
+/*
+ * Find TAG in XML and return a pointer into xml set just behind the
+ * closing angle.  Return NULL if not found. 
+ */
+static const char *
+find_xml_tag (const char *xml, const char *tag)
+{
+    int taglen = strlen (tag);
+    const char *s = xml;
+ 
+    while ( (s = strchr (s, '<')) ) {
+        s++;
+        if (!strncmp (s, tag, taglen)) {
+            const char *s2 = s + taglen;
+            if (*s2 == '>' || isspace (*(const unsigned char*)s2) ) {
+                /* found */
+                while (*s2 && *s2 != '>') /* skip attributes */
+                    s2++;
+                /* fixme: do need to handle angles inside attribute vallues? */
+                return *s2? (s2+1):NULL;
+            }
+        }
+        while (*s && *s != '>') /* skip to end of tag */
+            s++;
+    }
+    return NULL;
+}
+
+
+/*
+ * Extract the micalg from an GnupgOperationInfo XML container.
+ */
+static char *
+extract_micalg (char *xml)
+{
+    const char *s;
+
+    s = find_xml_tag (xml, "GnupgOperationInfo");
+    if (s) {
+        const char *s_end = find_xml_tag (s, "/GnupgOperationInfo");
+        s = find_xml_tag (s, "signature");
+        if (s && s_end && s < s_end) {
+            const char *s_end2 = find_xml_tag (s, "/signature");
+            if (s_end2 && s_end2 < s_end) {
+                s = find_xml_tag (s, "micalg");
+                if (s && s < s_end2) {
+                    s_end = strchr (s, '<');
+                    if (s_end) {
+                        char *p = g_malloc (s_end - s + 1);
+                        memcpy (p, s, s_end - s);
+                        p[s_end-s] = 0;
+                        return p;
+                    }
+                }
+            }
+        }
+    }
+    return NULL;
+}
+
+
+/*
+ * Sign the file and replace its content with the signed one.
+ */
+int
+rfc2015_sign (const char *file, GSList *key_list)
+{
+    FILE *fp = NULL;
+    char buf[BUFFSIZE];
+    int i, clineidx, saved_last;
+    char *clines[3] = {NULL};
+    GpgmeError err;
+    GpgmeData header = NULL;
+    GpgmeData plain = NULL;
+    GpgmeData sigdata = NULL;
+    size_t nread;
+    int mime_version_seen = 0;
+    char *boundary;
+    char *micalg = NULL;
+    char *siginfo;
+
+    boundary = generate_mime_boundary ("Signature");
+
+    /* Open the source file */
+    if ((fp = fopen(file, "rb")) == NULL) {
+        FILE_OP_ERROR(file, "fopen");
+        goto failure;
+    }
+
+    err = gpgme_data_new (&header);
+    if (!err)
+        err = gpgme_data_new (&plain);
+    if (err) {
+        debug_print ("gpgme_data_new failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    /* get the content header lines from the source */
+    clineidx = 0;
+    saved_last = 0;
+    while (!err && fgets(buf, sizeof(buf), fp)) {
+        /* fixme: check for overlong lines */
+        if (headerp (buf, content_names)) {
+            if (clineidx >= DIM (clines)) {
+                debug_print ("rfc2015_sign: too many content lines\n");
+                goto failure;
+            }
+            clines[clineidx++] = g_strdup (buf);
+            saved_last = 1;
+            continue;
+        }
+        if (saved_last) {
+            if (*buf == ' ' || *buf == '\t') {
+                char *last = clines[clineidx - 1];
+                clines[clineidx - 1] = g_strconcat (last, buf, NULL);
+                g_free (last);
+                continue;
+            }
+            saved_last = 0;
+        }
+
+        if (headerp (buf, mime_version_name)) 
+            mime_version_seen = 1;
+
+        if (buf[0] == '\r' || buf[0] == '\n')
+            break;
+        err = gpgme_data_write (header, buf, strlen (buf));
+    }
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fgets");
+        goto failure;
+    }
+
+    /* write them to the temp data and add the rest of the message */
+    for (i = 0; !err && i < clineidx; i++) {
+        err = gpgme_data_write (plain, clines[i], strlen (clines[i]));
+    }
+    if (!err)
+        err = gpgme_data_write (plain, "\r\n", 2 );
+    while (!err && fgets(buf, sizeof(buf), fp)) {
+        err = gpgme_data_write (plain, buf, strlen (buf));
+    }
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fgets");
+        goto failure;
+    }
+    if (err) {
+        debug_print ("gpgme_data_write failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    sigdata = pgp_sign (plain, key_list, FALSE, &siginfo); 
+    if (siginfo) {
+	micalg = extract_micalg (siginfo);
+	free (siginfo);
+    }
+    if (!sigdata) 
+        goto failure;
+
+    /* we have the signed message available in sigdata and now we are
+     * going to rewrite the original file. To be sure that file has
+     * been truncated we use an approach which should work everywhere:
+     * close the file and then reopen it for writing. */
+    if (fclose (fp)) {
+        FILE_OP_ERROR(file, "fclose");
+        goto failure;
+    }
+    if ((fp = fopen(file, "wb")) == NULL) {
+        FILE_OP_ERROR(file, "fopen");
+        goto failure;
+    }
+
+    /* Write the rfc822 header and add new content lines */
+    err = gpgme_data_rewind (header);
+    if (err)
+        debug_print ("gpgme_data_rewind failed: %s\n", gpgme_strerror (err));
+    while (!(err = gpgme_data_read (header, buf, BUFFSIZE, &nread))) {
+        fwrite (buf, nread, 1, fp);
+    }
+    if (err != GPGME_EOF) {
+        debug_print ("gpgme_data_read failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fwrite");
+        goto failure;
+    }
+    gpgme_data_release (header);
+    header = NULL;
+
+    if (!mime_version_seen) 
+        fputs ("MIME-Version: 1.0\r\n", fp);
+    fprintf (fp, "Content-Type: multipart/signed; "
+             "protocol=\"application/pgp-signature\";\r\n");
+    if (micalg)
+        fprintf (fp, " micalg=\"%s\";\r\n", micalg);
+    fprintf (fp, " boundary=\"%s\"\r\n", boundary);
+
+    /* Part 1: signed material */
+    fprintf (fp, "\r\n"
+                 "--%s\r\n",
+                 boundary);
+    err = gpgme_data_rewind (plain);
+    if (err) {
+        debug_print ("gpgme_data_rewind on plain failed: %s\n",
+                   gpgme_strerror (err));
+        goto failure;
+    }
+    while (!(err = gpgme_data_read (plain, buf, BUFFSIZE, &nread))) {
+        fwrite (buf, nread, 1, fp);   
+    }
+    if (err != GPGME_EOF) {
+        debug_print ("gpgme_data_read failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    /* Part 2: signature */
+    fprintf (fp, "\r\n"
+                 "--%s\r\n",
+                 boundary);
+    fputs ("Content-Type: application/pgp-signature\r\n"
+	   "\r\n", fp);
+
+    err = gpgme_data_rewind (sigdata);
+    if (err) {
+        debug_print ("gpgme_data_rewind on sigdata failed: %s\n",
+                   gpgme_strerror (err));
+        goto failure;
+    }
+
+    while (!(err = gpgme_data_read (sigdata, buf, BUFFSIZE, &nread))) {
+        fwrite (buf, nread, 1, fp);
+    }
+    if (err != GPGME_EOF) {
+        debug_print ("gpgme_data_read failed: %s\n", gpgme_strerror (err));
+        goto failure;
+    }
+
+    /* Final boundary */
+    fprintf (fp, "\r\n"
+                 "--%s--\r\n",
+                 boundary);
+    fflush (fp);
+    if (ferror (fp)) {
+        FILE_OP_ERROR (file, "fwrite");
+        goto failure;
+    }
+    fclose (fp);
+    gpgme_data_release (header);
+    gpgme_data_release (plain);
+    gpgme_data_release (sigdata);
+    g_free (boundary);
+    g_free (micalg);
+    return 0;
+
+failure:
+    if (fp) 
+        fclose (fp);
+    gpgme_data_release (header);
+    gpgme_data_release (plain);
+    gpgme_data_release (sigdata);
+    g_free (boundary);
+    g_free (micalg);
+    return -1; /* error */
+}
+
+
+/*
+ * Sign the file with clear text and replace its content with the signed one.
+ */
+gint
+rfc2015_clearsign (const gchar *file, GSList *key_list)
+{
+    FILE *fp;
+    gchar buf[BUFFSIZE];
+    GpgmeError err;
+    GpgmeData text = NULL;
+    GpgmeData sigdata = NULL;
+    size_t nread;
+    gchar *siginfo;
+
+    if ((fp = fopen(file, "rb")) == NULL) {
+	FILE_OP_ERROR(file, "fopen");
+	goto failure;
+    }
+
+    err = gpgme_data_new(&text);
+    if (err) {
+	debug_print("gpgme_data_new failed: %s\n", gpgme_strerror(err));
+	goto failure;
+    }
+
+    while (!err && fgets(buf, sizeof(buf), fp)) {
+	err = gpgme_data_write(text, buf, strlen(buf));
+    }
+    if (ferror(fp)) {
+	FILE_OP_ERROR(file, "fgets");
+	goto failure;
+    }
+    if (err) {
+	debug_print("gpgme_data_write failed: %s\n", gpgme_strerror(err));
+	goto failure;
+    }
+
+    sigdata = pgp_sign(text, key_list, TRUE, &siginfo);
+    if (siginfo) {
+	g_free(siginfo);
+    }
+    if (!sigdata)
+	goto failure;
+
+    if (fclose(fp) == EOF) {
+	FILE_OP_ERROR(file, "fclose");
+	fp = NULL;
+	goto failure;
+    }
+    if ((fp = fopen(file, "wb")) == NULL) {
+	FILE_OP_ERROR(file, "fopen");
+	goto failure;
+    }
+
+    err = gpgme_data_rewind(sigdata);
+    if (err) {
+	debug_print("gpgme_data_rewind on sigdata failed: %s\n",
+		    gpgme_strerror(err));
+	goto failure;
+    }
+
+    while (!(err = gpgme_data_read(sigdata, buf, sizeof(buf), &nread))) {
+	fwrite(buf, nread, 1, fp);
+    }
+    if (err != GPGME_EOF) {
+	debug_print("gpgme_data_read failed: %s\n", gpgme_strerror(err));
+	goto failure;
+    }
+
+    if (fclose(fp) == EOF) {
+	FILE_OP_ERROR(file, "fclose");
+	fp = NULL;
+	goto failure;
+    }
+    gpgme_data_release(text);
+    gpgme_data_release(sigdata);
+    return 0;
+
+failure:
+    if (fp)
+	fclose(fp);
+    gpgme_data_release(text);
+    gpgme_data_release(sigdata);
+    return -1;
+}
+
+#endif /* USE_GPGME */