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Diffstat (limited to 'main.c')
| -rw-r--r-- | main.c | 482 |
1 files changed, 482 insertions, 0 deletions
@@ -0,0 +1,482 @@ +/* + * A libESMTP Example Application. + * Copyright (C) 2001,2002 Brian Stafford <brian@stafford.uklinux.net> + * + * 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 + */ + +/* This program attemps to mimic the sendmail program behavior using libESMTP. + * + * Adapted from the libESMTP's mail-file example by José Fonseca. + */ +#define _XOPEN_SOURCE 500 + +#include <stdio.h> +#include <stdlib.h> +#include <ctype.h> +#include <unistd.h> +#include <getopt.h> +#include <string.h> +#include <fcntl.h> +#include <signal.h> +#include <errno.h> + +#include <auth-client.h> +#include <libesmtp.h> + +char *from = NULL; +char *host = NULL; +char *user = NULL; +char *pass = NULL; +enum starttls_option starttls = Starttls_DISABLED; +char *certificate_passphrase = NULL; + +extern void parse_rcfile(void); + +/* Callback function to read the message from a file. Since libESMTP + does not provide callbacks which translate line endings, one must + be provided by the application. + + The message is read a line at a time and the newlines converted + to \r\n. Unfortunately, RFC 822 states that bare \n and \r are + acceptable in messages and that individually they do not constitute a + line termination. This requirement cannot be reconciled with storing + messages with Unix line terminations. RFC 2822 rescues this situation + slightly by prohibiting lone \r and \n in messages. + + The following code cannot therefore work correctly in all situations. + Furthermore it is very inefficient since it must search for the \n. + */ +#define BUFLEN 8192 + +const char * +readlinefp_cb (void **buf, int *len, void *arg) +{ + int octets; + + if (*buf == NULL) + *buf = malloc (BUFLEN); + + if (len == NULL) + { + rewind ((FILE *) arg); + return NULL; + } + + if (fgets (*buf, BUFLEN - 2, (FILE *) arg) == NULL) + octets = 0; + else + { + char *p = strchr (*buf, '\0'); + + if (p[-1] == '\n' && p[-2] != '\r') + { + strcpy (p - 1, "\r\n"); + p++; + } + octets = p - (char *) *buf; + } + *len = octets; + return *buf; +} + +void +monitor_cb (const char *buf, int buflen, int writing, void *arg) +{ + FILE *fp = arg; + + if (writing == SMTP_CB_HEADERS) + { + fputs ("H: ", fp); + fwrite (buf, 1, buflen, fp); + return; + } + + fputs (writing ? "C: " : "S: ", fp); + fwrite (buf, 1, buflen, fp); + if (buf[buflen - 1] != '\n') + putc ('\n', fp); +} + +void +usage (void) +{ + fputs ("usage: esmtp [options] mailbox [mailbox ...]\n", + stderr); +} + +void +version (void) +{ + char buf[32]; + + smtp_version (buf, sizeof buf, 0); + printf ("libESMTP version %s\n", buf); +} + +/* Callback to request user/password info. Not thread safe. */ +int +authinteract (auth_client_request_t request, char **result, int fields, + void *arg) +{ + int i; + + for (i = 0; i < fields; i++) + { + if (request[i].flags & AUTH_USER && user) + result[i] = user; + else if (request[i].flags & AUTH_PASS && pass) + result[i] = pass; + else + return 0; + } + return 1; +} + +int +tlsinteract (char *buf, int buflen, int rwflag, void *arg) +{ + char *pw; + int len; + + if (certificate_passphrase) + { + pw = certificate_passphrase; + len = strlen (pw); + if (len + 1 > buflen) + return 0; + strcpy (buf, pw); + return len; + } + else + return 0; +} + +/* Callback to print the recipient status */ +void +print_recipient_status (smtp_recipient_t recipient, + const char *mailbox, void *arg) +{ + const smtp_status_t *status; + + status = smtp_recipient_status (recipient); + fprintf (stderr, "%s: %d %s\n", mailbox, status->code, status->text); +} + +int +main (int argc, char **argv) +{ + smtp_session_t session; + smtp_message_t message; + smtp_recipient_t recipient; + auth_context_t authctx; + const smtp_status_t *status; + struct sigaction sa; + int c; + int ret; + enum notify_flags notify = Notify_NOTSET; + + /* Parse the rc file. */ + parse_rcfile(); + + /* This program sends only one message at a time. Create an SMTP + session and add a message to it. */ + auth_client_init (); + session = smtp_create_session (); + message = smtp_add_message (session); + + while ((c = getopt (argc, argv, + "A:B:b:C:cd:e:F:f:Gh:IiL:M:mN:nO:o:p:q:R:r:sTtV:vX:")) != EOF) + switch (c) + { + case 'A': + /* Use alternate sendmail/submit.cf */ + break; + + case 'B': + /* Body type */ + break; + + case 'C': + /* Select configuration file */ + break; + + case 'F': + /* Set full name */ + break; + + case 'G': + /* Relay (gateway) submission */ + break; + + case 'I': + /* Initialize alias database */ + break; + + case 'L': + /* Program label */ + break; + + case 'M': + /* Define macro */ + break; + + case 'N': + /* Delivery status notifications */ + if (strcmp (optarg, "never") == 0) + notify = Notify_NEVER; + else + { + if (strstr (optarg, "failure")) + notify |= Notify_FAILURE; + if (strstr (optarg, "delay")) + notify |= Notify_DELAY; + if (strstr (optarg, "success")) + notify |= Notify_SUCCESS; + } + break; + + case 'R': + /* What to return */ + break; + + case 'T': + /* Set timeout interval */ + break; + + case 'X': + /* Traffic log file */ + break; + + case 'V': + /* Set original envelope id */ + break; + + case 'b': + /* Operations mode */ + break; + + case 'c': + /* Connect to non-local mailers */ + break; + + case 'd': + /* Debugging */ + break; + + case 'e': + /* Error message disposition */ + break; + + case 'f': + /* From address */ + case 'r': + /* Obsolete -f flag */ + from = optarg; + break; + + case 'h': + /* Hop count */ + break; + + case 'i': + /* Don't let dot stop me */ + break; + + case 'm': + /* Send to me too */ + break; + + case 'n': + /* don't alias */ + break; + + case 'o': + /* Set option */ + break; + + case 'p': + /* Set protocol */ + break; + + case 'q': + /* Run queue files at intervals */ + if (optarg[0] == '!') + { + /* Negate the meaning of pattern match */ + optarg++; + } + + switch (optarg[0]) + { + case 'G': + /* Limit by queue group name */ + break; + + case 'I': + /* Limit by ID */ + break; + + case 'R': + /* Limit by recipient */ + break; + + case 'S': + /* Limit by sender */ + break; + + case 'f': + /* Forground queue run */ + break; + + case 'p': + /* Persistent queue */ + if (optarg[1] == '\0') + break; + ++optarg; + + default: + break; + } + break; + + case 's': + /* Save From lines in headers */ + break; + + case 't': + /* Read recipients from message */ + fprintf (stderr, "Unsupported option 't'\n"); + exit (2); + break; + + case 'v': + /* Verbose */ + smtp_set_monitorcb (session, monitor_cb, stdout, 1); + break; + + default: + usage (); + exit (2); + } + + /* At least one more argument is needed. + */ + if (optind > argc - 1) + { + usage (); + exit (2); + } + + /* NB. libESMTP sets timeouts as it progresses through the protocol. + In addition the remote server might close its socket on a timeout. + Consequently libESMTP may sometimes try to write to a socket with + no reader. Ignore SIGPIPE, then the program doesn't get killed + if/when this happens. */ + sa.sa_handler = SIG_IGN; + sigemptyset (&sa.sa_mask); + sa.sa_flags = 0; + sigaction (SIGPIPE, &sa, NULL); + + /* Set the SMTP Starttls extension. */ + smtp_starttls_enable (session, starttls); + + /* Set the host running the SMTP server. LibESMTP has a default port + number of 587, however this is not widely deployed so the port + is specified as 25 along with the default MTA host. */ + smtp_set_server (session, host ? host : "localhost:25"); + + /* Do what's needed at application level to use authentication. + */ + authctx = auth_create_context (); + auth_set_mechanism_flags (authctx, AUTH_PLUGIN_PLAIN, 0); + auth_set_interact_cb (authctx, authinteract, NULL); + + /* Use our callback for X.509 certificate passwords. If STARTTLS is + not in use or disabled in configure, the following is harmless. */ + smtp_starttls_set_password_cb (tlsinteract, NULL); + + /* Now tell libESMTP it can use the SMTP AUTH extension. + */ + smtp_auth_set_context (session, authctx); + + /* Set the reverse path for the mail envelope. (NULL is ok) + */ + smtp_set_reverse_path (message, from); + + /* Open the message file and set the callback to read it. + */ +#if 0 + smtp_set_message_fp (message, stdin); +#else + smtp_set_messagecb (message, readlinefp_cb, stdin); +#endif + + /* At present it can't handle one recipient only out of many + failing. Make libESMTP require all specified recipients to + succeed before transferring a message. */ + smtp_option_require_all_recipients (session, 1); + + /* Add remaining program arguments as message recipients. + */ + while (optind < argc) + { + recipient = smtp_add_recipient (message, argv[optind++]); + + /* Recipient options set here */ + if (notify != Notify_NOTSET) + smtp_dsn_set_notify (recipient, notify); + } + + /* Initiate a connection to the SMTP server and transfer the + message. */ + if (!smtp_start_session (session)) + { + char buf[128]; + + fprintf (stderr, "SMTP server problem %s\n", + smtp_strerror (smtp_errno (), buf, sizeof buf)); + + ret = 1; + } + else + { + /* Report on the success or otherwise of the mail transfer. + */ + status = smtp_message_transfer_status (message); + if (status->code / 100 == 2) + { + ret = 0; + } + else + { + /* Report on the failure of the mail transfer. + */ + status = smtp_message_transfer_status (message); + fprintf (stderr, "%d %s\n", status->code, status->text); + smtp_enumerate_recipients (message, print_recipient_status, NULL); + + ret = 1; + } + } + + /* Free resources consumed by the program. + */ + smtp_destroy_session (session); + auth_destroy_context (authctx); + auth_client_exit (); + exit (ret); +} + |