add mailutils/*

1 files changed, 388 insertions, 0 deletions

diff --git a/mailutils/sendmail.c b/mailutils/sendmail.c
new file mode 100644
index 0000000..55555c3
--- /dev/null
+++ b/mailutils/sendmail.c
@@ -0,0 +1,388 @@
+/* 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;
+}