add mailutils/*

1 files changed, 388 insertions, 0 deletions

diff --git a/mailutils/sendmail.c b/mailutils/sendmail.c
new file mode 100644
index 000000000..55555c326
--- /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;
+}