mailutils/sendmail.c - busybox - Git at Google

 /* vi: set sw=4 ts=4: */
 /*
  * bare bones sendmail
  *
  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
  *
  * Licensed under GPLv2, see file LICENSE in this tarball for details.
  */
 #include "libbb.h"
 #include "mail.h"

 static int smtp_checkp(const char *fmt, const char *param, int code)
 {
 	char *answer;
 	const char *msg = command(fmt, param);
 	// read stdin
 	// if the string has a form \d\d\d- -- read next string. E.g. EHLO response
 	// parse first bytes to a number
 	// if code = -1 then just return this number
 	// if code != -1 then checks whether the number equals the code
 	// if not equal -> die saying msg
 	while ((answer = xmalloc_fgetline(stdin)) != NULL)
 		if (strlen(answer) <= 3 || '-' != answer[3])
 			break;
 	if (answer) {
 		int n = atoi(answer);
 		if (timeout)
 			alarm(0);
 		free(answer);
 		if (-1 == code || n == code)
 			return n;
 	}
 	bb_error_msg_and_die("%s failed", msg);
 }

 static int smtp_check(const char *fmt, int code)
 {
 	return smtp_checkp(fmt, NULL, code);
 }

 // strip argument of bad chars
 static char *sane_address(char *str)
 {
 	char *s = str;
 	char *p = s;
 	while (*s) {
 		if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) {
 			*p++ = *s;
 		}
 		s++;
 	}
 	*p = '\0';
 	return str;
 }

 static void rcptto(const char *s)
 {
 	smtp_checkp("RCPT TO:<%s>", s, 250);
 }

 int sendmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int sendmail_main(int argc UNUSED_PARAM, char **argv)
 {
 #if ENABLE_FEATURE_SENDMAIL_MAILX
 	llist_t *opt_attachments = NULL;
 	const char *opt_subject;
 #if ENABLE_FEATURE_SENDMAIL_MAILXX
 	llist_t *opt_carboncopies = NULL;
 	char *opt_errors_to;
 #endif
 #endif
 	char *opt_connect = opt_connect;
 	char *opt_from, *opt_fullname;
 	char *boundary;
 	llist_t *l;
 	llist_t *headers = NULL;
 	char *domain = sane_address(safe_getdomainname());
 	int code;

 	enum {
 		OPT_w = 1 << 0,         // network timeout
 		OPT_t = 1 << 1,         // read message for recipients
 		OPT_N = 1 << 2,         // request notification
 		OPT_f = 1 << 3,         // sender address
 		OPT_F = 1 << 4,         // sender name, overrides $NAME
 		OPT_s = 1 << 5,         // subject
 		OPT_j = 1 << 6,         // assumed charset
 		OPT_a = 1 << 7,         // attachment(s)
 		OPT_H = 1 << 8,         // use external connection helper
 		OPT_S = 1 << 9,         // specify connection string
 		OPT_c = 1 << 10,        // carbon copy
 		OPT_e = 1 << 11,        // errors-to address
 	};

 	// init global variables
 	INIT_G();

 	// save initial stdin since body is piped!
 	xdup2(STDIN_FILENO, 3);
 	G.fp0 = fdopen(3, "r");

 	// parse options
 	opt_complementary = "w+" USE_FEATURE_SENDMAIL_MAILX(":a::H--S:S--H") USE_FEATURE_SENDMAIL_MAILXX(":c::");
 	opts = getopt32(argv,
 		"w:t" "N:f:F:" USE_FEATURE_SENDMAIL_MAILX("s:j:a:H:S:") USE_FEATURE_SENDMAIL_MAILXX("c:e:")
 		"X:V:vq:R:O:o:nmL:Iih:GC:B:b:A:" // postfix compat only, ignored
 		// r:Q:p:M:Dd are candidates from another man page. TODO?
 		"46E", // ssmtp introduces another quirks. TODO?: -a[upm] (user, pass, method) to be supported
 		&timeout /* -w */, NULL, &opt_from, &opt_fullname,
 		USE_FEATURE_SENDMAIL_MAILX(&opt_subject, &G.opt_charset, &opt_attachments, &opt_connect, &opt_connect,)
 		USE_FEATURE_SENDMAIL_MAILXX(&opt_carboncopies, &opt_errors_to,)
 		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
 	);
 	//argc -= optind;
 	argv += optind;

 	// connect to server

 #if ENABLE_FEATURE_SENDMAIL_MAILX
 	// N.B. -H and -S are mutually exclusive so they do not spoil opt_connect
 	// connection helper ordered? ->
 	if (opts & OPT_H) {
 		const char *args[] = { "sh", "-c", opt_connect, NULL };
 		// plug it in
 		launch_helper(args);
 	// vanilla connection
 	} else
 #endif
 	{
 		int fd;
 		// host[:port] not explicitly specified ? -> use $SMTPHOST
 		// no $SMTPHOST ? -> use localhost
 		if (!(opts & OPT_S)) {
 			opt_connect = getenv("SMTPHOST");
 			if (!opt_connect)
 				opt_connect = (char *)"127.0.0.1";
 		}
 		// do connect
 		fd = create_and_connect_stream_or_die(opt_connect, 25);
 		// and make ourselves a simple IO filter
 		xmove_fd(fd, STDIN_FILENO);
 		xdup2(STDIN_FILENO, STDOUT_FILENO);
 	}
 	// N.B. from now we know nothing about network :)

 	// wait for initial server OK
 	// N.B. if we used openssl the initial 220 answer is already swallowed during openssl TLS init procedure
 	// so we need to push the server to see whether we are ok
 	code = smtp_check("NOOP", -1);
 	// 220 on plain connection, 250 on openssl-helped TLS session
 	if (220 == code)
 		smtp_check(NULL, 250); // reread the code to stay in sync
 	else if (250 != code)
 		bb_error_msg_and_die("INIT failed");

 	// we should start with modern EHLO
 	if (250 != smtp_checkp("EHLO %s", domain, -1)) {
 		smtp_checkp("HELO %s", domain, 250);
 	}

 	// set sender
 	// N.B. we have here a very loosely defined algotythm
 	// since sendmail historically offers no means to specify secrets on cmdline.
 	// 1) server can require no authentication ->
 	//	we must just provide a (possibly fake) reply address.
 	// 2) server can require AUTH ->
 	//	we must provide valid username and password along with a (possibly fake) reply address.
 	//	For the sake of security username and password are to be read either from console or from a secured file.
 	//	Since reading from console may defeat usability, the solution is either to read from a predefined
 	//	file descriptor (e.g. 4), or again from a secured file.

 	// got no sender address? -> use system username as a resort
 	if (!(opts & OPT_f)) {
 		// N.B. IMHO getenv("USER") can be way easily spoofed!
 		G.user = bb_getpwuid(NULL, -1, getuid());
 		opt_from = xasprintf("%s@%s", G.user, domain);
 	}
 	if (ENABLE_FEATURE_CLEAN_UP)
 		free(domain);

 	code = -1; // first try softly without authentication
 	while (250 != smtp_checkp("MAIL FROM:<%s>", opt_from, code)) {
 		// MAIL FROM failed -> authentication needed
 		if (334 == smtp_check("AUTH LOGIN", -1)) {
 			// we must read credentials
 			get_cred_or_die(4);
 			encode_base64(NULL, G.user, NULL);
 			smtp_check("", 334);
 			encode_base64(NULL, G.pass, NULL);
 			smtp_check("", 235);
 		}
 		// authenticated OK? -> retry to set sender
 		// but this time die on failure!
 		code = 250;
 	}

 	// recipients specified as arguments
 	while (*argv) {
 		char *s = sane_address(*argv);
 		// loose test on email address validity
 //		if (strchr(s, '@')) {
 			rcptto(s);
 			llist_add_to_end(&headers, xasprintf("To: %s", s));
 //		}
 		argv++;
 	}

 #if ENABLE_FEATURE_SENDMAIL_MAILXX
 	// carbon copies recipients specified as -c options
 	for (l = opt_carboncopies; l; l = l->link) {
 		char *s = sane_address(l->data);
 		// loose test on email address validity
 //		if (strchr(s, '@')) {
 			rcptto(s);
 			// TODO: do we ever need to mangle the message?
 			//llist_add_to_end(&headers, xasprintf("Cc: %s", s));
 //		}
 	}
 #endif

 	// if -t specified or no recipients specified -> read recipients from message
 	// i.e. scan stdin for To:, Cc:, Bcc: lines ...
 	// ... and then use the rest of stdin as message body
 	// N.B. subject read from body can be further overrided with one specified on command line.
 	// recipients are merged. Bcc: lines are deleted
 	// N.B. other headers are collected and will be dumped verbatim
 	if (opts & OPT_t || !headers) {
 		// fetch recipients and (optionally) subject
 		char *s;
 		while ((s = xmalloc_fgetline(G.fp0)) != NULL) {
 			if (0 == strncasecmp("To: ", s, 4) || 0 == strncasecmp("Cc: ", s, 4)) {
 				rcptto(sane_address(s+4));
 				llist_add_to_end(&headers, s);
 			} else if (0 == strncasecmp("Bcc: ", s, 5)) {
 				rcptto(sane_address(s+5));
 				free(s);
 				// N.B. Bcc vanishes from headers!
 			} else if (0 == strncmp("Subject: ", s, 9)) {
 				// we read subject -> use it verbatim unless it is specified
 				// on command line
 				if (!(opts & OPT_s))
 					llist_add_to_end(&headers, s);
 				else
 					free(s);
 			} else if (s[0]) {
 				// misc header
 				llist_add_to_end(&headers, s);
 			} else {
 				free(s);
 				break; // stop on the first empty line
 			}
 		}
 	}

 	// enter "put message" mode
 	smtp_check("DATA", 354);

 	// put headers we could have preread with -t
 	for (l = headers; l; l = l->link) {
 		printf("%s\r\n", l->data);
 		if (ENABLE_FEATURE_CLEAN_UP)
 			free(l->data);
 	}

 	// put (possibly encoded) subject
 #if ENABLE_FEATURE_SENDMAIL_MAILX
 	if (opts & OPT_s) {
 		printf("Subject: ");
 		if (opts & OPT_j) {
 			printf("=?%s?B?", G.opt_charset);
 			encode_base64(NULL, opt_subject, NULL);
 			printf("?=");
 		} else {
 			printf("%s", opt_subject);
 		}
 		printf("\r\n");
 	}
 #endif

 	// put sender name, $NAME is the default
 	if (!(opts & OPT_F))
 		opt_fullname = getenv("NAME");
 	if (opt_fullname)
 		printf("From: \"%s\" <%s>\r\n", opt_fullname, opt_from);

 	// put notification
 	if (opts & OPT_N)
 		printf("Disposition-Notification-To: %s\r\n", opt_from);

 #if ENABLE_FEATURE_SENDMAIL_MAILXX
 	// put errors recipient
 	if (opts & OPT_e)
 		printf("Errors-To: %s\r\n", opt_errors_to);
 #endif

 	// make a random string -- it will delimit message parts
 	srand(monotonic_us());
 	boundary = xasprintf("%d=_%d-%d", rand(), rand(), rand());

 	// put common headers
 	// TODO: do we really need this?
 //	printf("Message-ID: <%s>\r\n", boundary);

 #if ENABLE_FEATURE_SENDMAIL_MAILX
 	// have attachments? -> compose multipart MIME
 	if (opt_attachments) {
 		const char *fmt;
 		const char *p;
 		char *q;

 		printf(
 			"Mime-Version: 1.0\r\n"
 			"%smultipart/mixed; boundary=\"%s\"\r\n"
 			, "Content-Type: "
 			, boundary
 		);

 		// body is pseudo attachment read from stdin in first turn
 		llist_add_to(&opt_attachments, (char *)"-");

 		// put body + attachment(s)
 		// N.B. all these weird things just to be tiny
 		// by reusing string patterns!
 		fmt =
 			"\r\n--%s\r\n"
 			"%stext/plain; charset=%s\r\n"
 			"%s%s\r\n"
 			"%s"
 		;
 		p = G.opt_charset;
 		q = (char *)"";
 		l = opt_attachments;
 		while (l) {
 			printf(
 				fmt
 				, boundary
 				, "Content-Type: "
 				, p
 				, "Content-Disposition: inline"
 				, q
 				, "Content-Transfer-Encoding: base64\r\n"
 			);
 			p = "";
 			fmt =
 				"\r\n--%s\r\n"
 				"%sapplication/octet-stream%s\r\n"
 				"%s; filename=\"%s\"\r\n"
 				"%s"
 			;
 			encode_base64(l->data, (const char *)G.fp0, "\r");
 			l = l->link;
 			if (l)
 				q = bb_get_last_path_component_strip(l->data);
 		}

 		// put message terminator
 		printf("\r\n--%s--\r\n" "\r\n", boundary);

 	// no attachments? -> just dump message
 	} else
 #endif
 	{
 		char *s;
 		// terminate headers
 		printf("\r\n");
 		// put plain text respecting leading dots
 		while ((s = xmalloc_fgetline(G.fp0)) != NULL) {
 			// escape leading dots
 			// N.B. this feature is implied even if no -i (-oi) switch given
 			// N.B. we need to escape the leading dot regardless of
 			// whether it is single or not character on the line
 			if ('.' == s[0] /*&& '\0' == s[1] */)
 				printf(".");
 			// dump read line
 			printf("%s\r\n", s);
 		}
 	}

 	// leave "put message" mode
 	smtp_check(".", 250);
 	// ... and say goodbye
 	smtp_check("QUIT", 221);
 	// cleanup
 	if (ENABLE_FEATURE_CLEAN_UP)
 		fclose(G.fp0);

 	return EXIT_SUCCESS;
 }
	/* vi: set sw=4 ts=4: */
	/*
	* bare bones sendmail
	*
	* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
	*
	* Licensed under GPLv2, see file LICENSE in this tarball for details.
	*/
	#include "libbb.h"
	#include "mail.h"

	static int smtp_checkp(const char fmt, const char param, int code)
	{
	char *answer;
	const char *msg = command(fmt, param);
	// read stdin
	// if the string has a form \d\d\d- -- read next string. E.g. EHLO response
	// parse first bytes to a number
	// if code = -1 then just return this number
	// if code != -1 then checks whether the number equals the code
	// if not equal -> die saying msg
	while ((answer = xmalloc_fgetline(stdin)) != NULL)
	if (strlen(answer) <= 3 \|\| '-' != answer[3])
	break;
	if (answer) {
	int n = atoi(answer);
	if (timeout)
	alarm(0);
	free(answer);
	if (-1 == code \|\| n == code)
	return n;
	}
	bb_error_msg_and_die("%s failed", msg);
	}

	static int smtp_check(const char *fmt, int code)
	{
	return smtp_checkp(fmt, NULL, code);
	}

	// strip argument of bad chars
	static char sane_address(char str)
	{
	char *s = str;
	char *p = s;
	while (*s) {
	if (isalnum(s) \|\| '_' == s \|\| '-' == s \|\| '.' == s \|\| '@' == *s) {
	p++ = s;
	}
	s++;
	}
	*p = '\0';
	return str;
	}

	static void rcptto(const char *s)
	{
	smtp_checkp("RCPT TO:<%s>", s, 250);
	}

	int sendmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int sendmail_main(int argc UNUSED_PARAM, char **argv)
	{
	#if ENABLE_FEATURE_SENDMAIL_MAILX
	llist_t *opt_attachments = NULL;
	const char *opt_subject;
	#if ENABLE_FEATURE_SENDMAIL_MAILXX
	llist_t *opt_carboncopies = NULL;
	char *opt_errors_to;
	#endif
	#endif
	char *opt_connect = opt_connect;
	char opt_from, opt_fullname;
	char *boundary;
	llist_t *l;
	llist_t *headers = NULL;
	char *domain = sane_address(safe_getdomainname());
	int code;

	enum {
	OPT_w = 1 << 0, // network timeout
	OPT_t = 1 << 1, // read message for recipients
	OPT_N = 1 << 2, // request notification
	OPT_f = 1 << 3, // sender address
	OPT_F = 1 << 4, // sender name, overrides $NAME
	OPT_s = 1 << 5, // subject
	OPT_j = 1 << 6, // assumed charset
	OPT_a = 1 << 7, // attachment(s)
	OPT_H = 1 << 8, // use external connection helper
	OPT_S = 1 << 9, // specify connection string
	OPT_c = 1 << 10, // carbon copy
	OPT_e = 1 << 11, // errors-to address
	};

	// init global variables
	INIT_G();

	// save initial stdin since body is piped!
	xdup2(STDIN_FILENO, 3);
	G.fp0 = fdopen(3, "r");

	// parse options
	opt_complementary = "w+" USE_FEATURE_SENDMAIL_MAILX(":a::H--S:S--H") USE_FEATURE_SENDMAIL_MAILXX(":c::");
	opts = getopt32(argv,
	"w:t" "N:f:F:" USE_FEATURE_SENDMAIL_MAILX("s:j:a:H:S:") USE_FEATURE_SENDMAIL_MAILXX("c:e:")
	"X:V:vq:R:O:o:nmL:Iih:GC:B:b:A:" // postfix compat only, ignored
	// r:Q:p:M:Dd are candidates from another man page. TODO?
	"46E", // ssmtp introduces another quirks. TODO?: -a[upm] (user, pass, method) to be supported
	&timeout /* -w */, NULL, &opt_from, &opt_fullname,
	USE_FEATURE_SENDMAIL_MAILX(&opt_subject, &G.opt_charset, &opt_attachments, &opt_connect, &opt_connect,)
	USE_FEATURE_SENDMAIL_MAILXX(&opt_carboncopies, &opt_errors_to,)
	NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
	);
	//argc -= optind;
	argv += optind;

	// connect to server

	#if ENABLE_FEATURE_SENDMAIL_MAILX
	// N.B. -H and -S are mutually exclusive so they do not spoil opt_connect
	// connection helper ordered? ->
	if (opts & OPT_H) {
	const char *args[] = { "sh", "-c", opt_connect, NULL };
	// plug it in
	launch_helper(args);
	// vanilla connection
	} else
	#endif
	{
	int fd;
	// host[:port] not explicitly specified ? -> use $SMTPHOST
	// no $SMTPHOST ? -> use localhost
	if (!(opts & OPT_S)) {
	opt_connect = getenv("SMTPHOST");
	if (!opt_connect)
	opt_connect = (char *)"127.0.0.1";
	}
	// do connect
	fd = create_and_connect_stream_or_die(opt_connect, 25);
	// and make ourselves a simple IO filter
	xmove_fd(fd, STDIN_FILENO);
	xdup2(STDIN_FILENO, STDOUT_FILENO);
	}
	// N.B. from now we know nothing about network :)

	// wait for initial server OK
	// N.B. if we used openssl the initial 220 answer is already swallowed during openssl TLS init procedure
	// so we need to push the server to see whether we are ok
	code = smtp_check("NOOP", -1);
	// 220 on plain connection, 250 on openssl-helped TLS session
	if (220 == code)
	smtp_check(NULL, 250); // reread the code to stay in sync
	else if (250 != code)
	bb_error_msg_and_die("INIT failed");

	// we should start with modern EHLO
	if (250 != smtp_checkp("EHLO %s", domain, -1)) {
	smtp_checkp("HELO %s", domain, 250);
	}

	// set sender
	// N.B. we have here a very loosely defined algotythm
	// since sendmail historically offers no means to specify secrets on cmdline.
	// 1) server can require no authentication ->
	// we must just provide a (possibly fake) reply address.
	// 2) server can require AUTH ->
	// we must provide valid username and password along with a (possibly fake) reply address.
	// For the sake of security username and password are to be read either from console or from a secured file.
	// Since reading from console may defeat usability, the solution is either to read from a predefined
	// file descriptor (e.g. 4), or again from a secured file.

	// got no sender address? -> use system username as a resort
	if (!(opts & OPT_f)) {
	// N.B. IMHO getenv("USER") can be way easily spoofed!
	G.user = bb_getpwuid(NULL, -1, getuid());
	opt_from = xasprintf("%s@%s", G.user, domain);
	}
	if (ENABLE_FEATURE_CLEAN_UP)
	free(domain);

	code = -1; // first try softly without authentication
	while (250 != smtp_checkp("MAIL FROM:<%s>", opt_from, code)) {
	// MAIL FROM failed -> authentication needed
	if (334 == smtp_check("AUTH LOGIN", -1)) {
	// we must read credentials
	get_cred_or_die(4);
	encode_base64(NULL, G.user, NULL);
	smtp_check("", 334);
	encode_base64(NULL, G.pass, NULL);
	smtp_check("", 235);
	}
	// authenticated OK? -> retry to set sender
	// but this time die on failure!
	code = 250;
	}

	// recipients specified as arguments
	while (*argv) {
	char s = sane_address(argv);
	// loose test on email address validity
	// if (strchr(s, '@')) {
	rcptto(s);
	llist_add_to_end(&headers, xasprintf("To: %s", s));
	// }
	argv++;
	}

	#if ENABLE_FEATURE_SENDMAIL_MAILXX
	// carbon copies recipients specified as -c options
	for (l = opt_carboncopies; l; l = l->link) {
	char *s = sane_address(l->data);
	// loose test on email address validity
	// if (strchr(s, '@')) {
	rcptto(s);
	// TODO: do we ever need to mangle the message?
	//llist_add_to_end(&headers, xasprintf("Cc: %s", s));
	// }
	}
	#endif

	// if -t specified or no recipients specified -> read recipients from message
	// i.e. scan stdin for To:, Cc:, Bcc: lines ...
	// ... and then use the rest of stdin as message body
	// N.B. subject read from body can be further overrided with one specified on command line.
	// recipients are merged. Bcc: lines are deleted
	// N.B. other headers are collected and will be dumped verbatim
	if (opts & OPT_t \|\| !headers) {
	// fetch recipients and (optionally) subject
	char *s;
	while ((s = xmalloc_fgetline(G.fp0)) != NULL) {
	if (0 == strncasecmp("To: ", s, 4) \|\| 0 == strncasecmp("Cc: ", s, 4)) {
	rcptto(sane_address(s+4));
	llist_add_to_end(&headers, s);
	} else if (0 == strncasecmp("Bcc: ", s, 5)) {
	rcptto(sane_address(s+5));
	free(s);
	// N.B. Bcc vanishes from headers!
	} else if (0 == strncmp("Subject: ", s, 9)) {
	// we read subject -> use it verbatim unless it is specified
	// on command line
	if (!(opts & OPT_s))
	llist_add_to_end(&headers, s);
	else
	free(s);
	} else if (s[0]) {
	// misc header
	llist_add_to_end(&headers, s);
	} else {
	free(s);
	break; // stop on the first empty line
	}
	}
	}

	// enter "put message" mode
	smtp_check("DATA", 354);

	// put headers we could have preread with -t
	for (l = headers; l; l = l->link) {
	printf("%s\r\n", l->data);
	if (ENABLE_FEATURE_CLEAN_UP)
	free(l->data);
	}

	// put (possibly encoded) subject
	#if ENABLE_FEATURE_SENDMAIL_MAILX
	if (opts & OPT_s) {
	printf("Subject: ");
	if (opts & OPT_j) {
	printf("=?%s?B?", G.opt_charset);
	encode_base64(NULL, opt_subject, NULL);
	printf("?=");
	} else {
	printf("%s", opt_subject);
	}
	printf("\r\n");
	}
	#endif

	// put sender name, $NAME is the default
	if (!(opts & OPT_F))
	opt_fullname = getenv("NAME");
	if (opt_fullname)
	printf("From: \"%s\" <%s>\r\n", opt_fullname, opt_from);

	// put notification
	if (opts & OPT_N)
	printf("Disposition-Notification-To: %s\r\n", opt_from);

	#if ENABLE_FEATURE_SENDMAIL_MAILXX
	// put errors recipient
	if (opts & OPT_e)
	printf("Errors-To: %s\r\n", opt_errors_to);
	#endif

	// make a random string -- it will delimit message parts
	srand(monotonic_us());
	boundary = xasprintf("%d=_%d-%d", rand(), rand(), rand());

	// put common headers
	// TODO: do we really need this?
	// printf("Message-ID: <%s>\r\n", boundary);

	#if ENABLE_FEATURE_SENDMAIL_MAILX
	// have attachments? -> compose multipart MIME
	if (opt_attachments) {
	const char *fmt;
	const char *p;
	char *q;

	printf(
	"Mime-Version: 1.0\r\n"
	"%smultipart/mixed; boundary=\"%s\"\r\n"
	, "Content-Type: "
	, boundary
	);

	// body is pseudo attachment read from stdin in first turn
	llist_add_to(&opt_attachments, (char *)"-");

	// put body + attachment(s)
	// N.B. all these weird things just to be tiny
	// by reusing string patterns!
	fmt =
	"\r\n--%s\r\n"
	"%stext/plain; charset=%s\r\n"
	"%s%s\r\n"
	"%s"
	;
	p = G.opt_charset;
	q = (char *)"";
	l = opt_attachments;
	while (l) {
	printf(
	fmt
	, boundary
	, "Content-Type: "
	, p
	, "Content-Disposition: inline"
	, q
	, "Content-Transfer-Encoding: base64\r\n"
	);
	p = "";
	fmt =
	"\r\n--%s\r\n"
	"%sapplication/octet-stream%s\r\n"
	"%s; filename=\"%s\"\r\n"
	"%s"
	;
	encode_base64(l->data, (const char *)G.fp0, "\r");
	l = l->link;
	if (l)
	q = bb_get_last_path_component_strip(l->data);
	}

	// put message terminator
	printf("\r\n--%s--\r\n" "\r\n", boundary);

	// no attachments? -> just dump message
	} else
	#endif
	{
	char *s;
	// terminate headers
	printf("\r\n");
	// put plain text respecting leading dots
	while ((s = xmalloc_fgetline(G.fp0)) != NULL) {
	// escape leading dots
	// N.B. this feature is implied even if no -i (-oi) switch given
	// N.B. we need to escape the leading dot regardless of
	// whether it is single or not character on the line
	if ('.' == s[0] /&& '\0' == s[1] /)
	printf(".");
	// dump read line
	printf("%s\r\n", s);
	}
	}

	// leave "put message" mode
	smtp_check(".", 250);
	// ... and say goodbye
	smtp_check("QUIT", 221);
	// cleanup
	if (ENABLE_FEATURE_CLEAN_UP)
	fclose(G.fp0);

	return EXIT_SUCCESS;
	}