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simvacation.c
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simvacation.c
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/*
* Copyright (c) Regents of The University of Michigan
* See COPYING.
*/
#include <config.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sysexits.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include "simvacation.h"
#include "vdb.h"
#include "vlu.h"
#include "vutil.h"
struct headers *readheaders(const ucl_object_t *);
static yastr pretty_sender(const char *, const char *);
yastr append_header(yastr, char *, int);
int check_header(char *, const char *);
int send_message(yastr, yastr, yastr, yastr, yastr, struct headers *);
/* RFC 2822 2.1.1
* There are two limits that this standard places on the number of
* characters in a line. Each line of characters MUST be no more than
* 998 characters, and SHOULD be no more than 78 characters, excluding
* the CRLF.
*/
#define MAXLINE 1000
extern int optind, opterr;
extern char *optarg;
int
main(int argc, char **argv) {
int retval = EX_OK;
bool debug = false;
int ch, rc;
yastr from = NULL;
yastr canon_from = NULL;
yastr rcpt;
yastr vacmsg = NULL;
yastr progname;
char *p;
char *config_file = NULL;
struct vdb_backend *vdb = NULL;
VDB * vdbh = NULL;
struct vlu_backend *vlu = NULL;
VLU * vluh = NULL;
struct headers * hdrs = NULL;
progname = yaslauto(argv[ 0 ]);
if ((p = strrchr(progname, '/')) != NULL) {
yaslrange(progname, p - progname + 1, -1);
}
openlog(progname, LOG_PID, LOG_VACATION);
opterr = 0;
while ((ch = getopt(argc, argv, "c:df:")) != EOF) {
switch ((char)ch) {
case 'c':
config_file = optarg;
break;
case 'd':
debug = true;
break;
case 'f':
from = yaslauto(optarg);
break;
case '?':
default:
retval = EX_USAGE;
}
}
argc -= optind;
argv += optind;
if ((!*argv) || (retval != EX_OK)) {
fprintf(stderr,
"usage: %s [-c conf_file] [-d] [-f from_address] to_address\n",
progname);
retval = EX_USAGE;
goto done;
}
if (debug) {
openlog(progname, LOG_NOWAIT | LOG_PERROR | LOG_PID, LOG_VACATION);
}
rcpt = yaslauto(*argv);
if (read_vacation_config(config_file) != VAC_RESULT_OK) {
retval = EX_TEMPFAIL;
goto done;
}
if ((vdb = vdb_backend(ucl_object_tostring(
ucl_object_lookup_path(vac_config, "core.vdb")))) == NULL) {
retval = EX_TEMPFAIL;
goto done;
}
if ((vlu = vlu_backend(ucl_object_tostring(
ucl_object_lookup_path(vac_config, "core.vlu")))) == NULL) {
retval = EX_TEMPFAIL;
goto done;
}
if ((vluh = vlu->init()) == NULL) {
retval = EX_TEMPFAIL;
goto done;
}
rc = vlu->search(vluh, rcpt);
if (rc == VAC_RESULT_PERMFAIL) {
rc = vlu->group_search(vluh, rcpt);
}
if (rc != VAC_RESULT_OK) {
if (rc != VAC_RESULT_PERMFAIL) {
retval = EX_TEMPFAIL;
}
goto done;
}
if ((vdbh = vdb->init(rcpt)) == NULL) {
goto done;
}
if ((hdrs = readheaders(vlu->aliases(vluh, rcpt))) == NULL) {
goto done;
}
if (!hdrs->rcpt_match) {
syslog(LOG_INFO, "message does not appear to be to %s", rcpt);
goto done;
}
if ((canon_from = check_from(from)) == NULL) {
syslog(LOG_INFO, "skipping message, bad sender %s", from);
goto done;
}
if (vdb->recent(vdbh, canon_from, vlu->interval(vluh, rcpt)) ==
VDB_STATUS_RECENT) {
syslog(LOG_DEBUG, "suppressed message for %s to %s", rcpt, from);
goto done;
}
/* All the checks have passed, send the message. */
vdb->store_reply(vdbh, canon_from);
if ((vacmsg = vlu->message(vluh, rcpt)) == NULL) {
vacmsg = yaslauto(ucl_object_tostring(
ucl_object_lookup_path(vac_config, "core.default_message")));
}
retval = send_message(pretty_sender(rcpt, vlu->display_name(vluh, rcpt)),
from, canon_from, vacmsg, vlu->subject_prefix(vluh, rcpt), hdrs);
if (retval == EX_OK) {
syslog(LOG_DEBUG, "sent message for %s to %s", rcpt, from);
}
done:
if (vdb) {
vdb->close(vdbh);
}
if (vlu) {
vlu->close(vluh);
}
exit(retval);
}
struct headers *
readheaders(const ucl_object_t *names) {
struct headers * h;
char * p;
int state, stripfield = 0;
char buf[ MAXLINE ];
yastr * current_hdr = NULL;
yastr rcpt_hdrs = yaslempty();
ucl_object_iter_t i;
const ucl_object_t *obj;
h = calloc(1, sizeof(struct headers));
h->rcpt_match = false;
state = HEADER_UNKNOWN;
while (fgets(buf, sizeof(buf), stdin) && *buf != '\n') {
if (check_header(buf, "Message-ID:") == 0) {
state = HEADER_APPEND;
stripfield = 1;
current_hdr = &h->messageid;
} else if (check_header(buf, "References:") == 0) {
state = HEADER_APPEND;
stripfield = 1;
current_hdr = &h->references;
} else if (check_header(buf, "In-Reply-To:") == 0) {
state = HEADER_APPEND;
stripfield = 1;
current_hdr = &h->inreplyto;
}
/* RFC 3834 2
* Automatic responses SHOULD NOT be issued in response to any
* message which contains an Auto-Submitted header field (see below),
* where that field has any value other than "no"
*/
else if (check_header(buf, "Auto-Submitted:") == 0) {
state = HEADER_NOREPLY;
p = buf + 15;
while (*++p && isspace(*p))
;
if (!*p) {
break;
}
if (strncasecmp(p, "no", 2) != 0) {
syslog(LOG_DEBUG, "readheaders: suppressing message: %s", buf);
return NULL;
}
}
/* RFC 3834 2
* A responder MAY refuse to send a response to a subject message
* which contains any header or content which makes it appear to the
* responder that a response would not be appropriate.
*/
else if (check_header(buf, "List-") == 0) {
/* RFC 3834 2
* For similar reasons, a responder MAY ignore any subject message
* with a List-* field [RFC2369].
*/
state = HEADER_NOREPLY;
syslog(LOG_DEBUG, "readheaders: suppressing message: %s", buf);
return NULL;
} else if (check_header(buf, "Precedence") == 0) {
/* RFC 3834 2
* For instance, if the subject message contained a
* Precedence header field [RFC2076] with a value of
* "list" the responder might guess that the traffic had
* arrived from a mailing list, and would not respond if
* the response were only intended for personal messages.
* [...]
* (Because Precedence is not a standard header field, and
* its use and interpretation vary widely in the wild,
* no particular responder behavior in the presence of
* Precedence is recommended by this specification.
*/
state = HEADER_NOREPLY;
if ((buf[ 10 ] == ':' || buf[ 10 ] == ' ' || buf[ 10 ] == '\t') &&
(p = index(buf, ':'))) {
while (*++p && isspace(*p))
;
if (!*p) {
break;
}
if (strncasecmp(p, "junk", 4) == 0 ||
strncasecmp(p, "bulk", 4) == 0 ||
strncasecmp(p, "list", 4) == 0) {
syslog(LOG_DEBUG,
"readheaders: suppressing message: precedence %s",
p);
return NULL;
}
}
} else if (check_header(buf, "X-Auto-Response-Suppress:") == 0) {
/* MS-OXCMAIL 2.1.3.2.20
*
* X-Auto-Response-Suppress value | Meaning
* ----------------------------------------------------------------
* None |
* ----------------------------------------------------------------
* All |
* ----------------------------------------------------------------
* DR | Suppress delivery reports
* | from transport.
* ----------------------------------------------------------------
* NDR | Suppress non-delivery reports
* | from transport.
* ----------------------------------------------------------------
* RN | Suppress read notifications
* | from receiving client.
* ----------------------------------------------------------------
* NRN | Suppress non-read
* | notifications from receiving
* | client.
* ----------------------------------------------------------------
* OOF | Suppress Out of Office (OOF)
* | notifications.
* ----------------------------------------------------------------
* AutoReply | Suppress auto-reply messages
* | other than OOF notifications.
* ----------------------------------------------------------------
*
* The order of these values in the header is not important.
*/
state = HEADER_NOREPLY;
if (is_substring("OOF", buf, false) ||
is_substring("All", buf, false)) {
syslog(LOG_DEBUG, "readheaders: suppressing message: %s", buf);
return NULL;
}
}
/* RFC 3834 2
* Personal and Group responses whose purpose is to notify the sender
* of a message of a temporary absence of the recipient (e.g.,
* "vacation" and "out of the office" notices) SHOULD NOT be issued
* unless a valid address for the recipient is explicitly included in
* a recipient (e.g., To, Cc, Bcc, Resent-To, Resent-Cc, or Resent-
* Bcc) field of the subject message.
*/
else if (check_header(buf, "Cc:") == 0) {
state = HEADER_RECIPIENT;
} else if (check_header(buf, "To:") == 0) {
state = HEADER_RECIPIENT;
} else if (check_header(buf, "Subject:") == 0) {
state = HEADER_APPEND;
stripfield = 1;
current_hdr = &h->subject;
} else if (!isspace(*buf)) {
/* Not a continuation of the previous header line, reset flag
*
* RFC 2822 2.2.3
* Unfolding is accomplished by simply removing any CRLF
* that is immediately followed by WSP.
*/
state = HEADER_UNKNOWN;
}
switch (state) {
case HEADER_RECIPIENT:
rcpt_hdrs = yaslcat(rcpt_hdrs, buf);
rcpt_hdrs = yaslcatlen(rcpt_hdrs, " ", 1);
break;
case HEADER_APPEND:
*current_hdr = append_header(*current_hdr, buf, stripfield);
stripfield = 0;
break;
}
}
i = ucl_object_iterate_new(names);
while (!h->rcpt_match &&
(obj = ucl_object_iterate_safe(i, false)) != NULL) {
h->rcpt_match = is_substring(ucl_object_tostring(obj), rcpt_hdrs, true);
}
ucl_object_iterate_free(i);
return h;
}
int
check_header(char *line, const char *field) {
return strncasecmp(field, line, strlen(field));
}
yastr
append_header(yastr str, char *value, int stripfield) {
if (stripfield) {
value = index(value, ':');
while (value && *++value && isspace(*value))
;
}
if (str == NULL) {
str = yaslempty();
}
yastr s = yaslcat(str, value);
yasltrim(s, "\n");
return s;
}
static yastr
pretty_sender(const char *sender, const char *sender_name) {
yastr retval = yaslempty();
const char *domain = ucl_object_tostring(
ucl_object_lookup_path(vac_config, "core.domain"));
if (sender_name && (strcasecmp(sender_name, sender) != 0)) {
retval = yaslcatprintf(
retval, "\"%s\" <%s@%s>", sender_name, sender, domain);
} else {
retval = yaslcatprintf(retval, "%s@%s", sender, domain);
}
return retval;
}
int
send_message(yastr sender, yastr rcpt, yastr canon_rcpt, yastr vmsg,
yastr subject, struct headers *h) {
char hostname[ 255 ];
int splitlen;
yastr *split;
split = yaslsplitargs(ucl_object_tostring(ucl_object_lookup_path(
vac_config, "core.sendmail")),
&splitlen);
split = realloc(split, (splitlen + 1) * sizeof(yastr));
split[ splitlen ] = NULL;
/* Replace placeholder with recipient */
for (int i = 0; i < splitlen; i++) {
if ((yasllen(split[ i ]) == 2) && (memcmp(split[ i ], "$R", 2) == 0)) {
split[ i ] = rcpt;
}
}
if ((pexecv(split)) != VAC_RESULT_OK) {
syslog(LOG_ERR, "mail: pexecv of %s failed", split[ 0 ]);
return EX_TEMPFAIL;
}
/*
* Our stdout should now be hooked up to sendmail's stdin.
* Generate headers and print the vacation message.
*/
gethostname(hostname, 255);
printf("Message-ID: <%llx_%x@%s>\n", (unsigned long long)time(NULL),
getpid(), hostname);
/* RFC 3834 3.1.1
* For responses sent by Personal Responders, the From field SHOULD
* contain the name of the recipient of the subject message (i.e.,
* the user on whose behalf the response is being sent) and an
* address chosen by the recipient of the subject message to be
* recognizable to correspondents. Often this will be the same
* address that was used to send the subject message to that
* recipient.
*/
printf("From: %s\n", sender);
/* RFC 3834 3.1.3
* The To header field SHOULD indicate the recipient of the response.
* In general there SHOULD only be one recipient of any automatic
* response. This minimizes the potential for sorcerer's apprentice
* mode and denial-of-service attacks.
*/
printf("To: %s\n", canon_rcpt);
/* RFC 3834 3.1.5
* The Subject field SHOULD contain a brief indication that the message
* is an automatic response, followed by contents of the Subject field
* (or a portion thereof) from the subject message. The prefix "Auto:"
* MAY be used as such an indication. If used, this prefix SHOULD be
* followed by an ASCII SPACE character (0x20).
*/
printf("Subject: %s", subject);
if (yasllen(h->subject) > 0) {
if (check_header(h->subject, "Re:") != 0) {
printf(" (Re: %s)", h->subject);
} else {
printf(" (%s)", h->subject);
}
}
printf("\n");
/* RFC 3834 3.1.6
* The In-Reply-To and References fields SHOULD be provided in the
* header of a response message if there was a Message-ID field in the
* subject message, according to the rules in [RFC2822] section
* 3.6.4.
*/
if (yasllen(h->messageid) > 0) {
/* RFC 2822 3.6.4
* The "In-Reply-To:" field will contain the contents of the
* "Message-ID:" field of the message to which this one is a reply
* (the "parent message"). [...] If there is no "Message-ID:" field
* in any of the parent messages, then the new message will have no
* "In-Reply-To:" field.
*/
printf("In-Reply-To: %s\n", h->messageid);
}
/* RFC 2822 3.6.4
* The "References:" field will contain the contents of the
* parent's "References:" field (if any) followed by the contents
* of the parent's "Message-ID:" field (if any). If the parent
* message does not contain a "References:" field but does have an
* "In-Reply-To:" field containing a single message identifier, then
* the "References:" field will contain the contents of the parent's
* "In-Reply-To:" field followed by the contents of the parent's
* "Message-ID:" field (if any).
*/
if (yasllen(h->references) > 0) {
printf("References: %s %s\n", h->references, h->messageid);
} else if (yasllen(h->inreplyto) > 0) {
printf("References: %s %s\n", h->inreplyto, h->messageid);
} else if (yasllen(h->messageid) > 0) {
printf("References: %s\n", h->messageid);
}
/* RFC 3834 3.1.7
* The Auto-Submitted field, with a value of "auto-replied", SHOULD be
* included in the message header of any automatic response.
*/
printf("Auto-Submitted: auto-replied\n");
printf("MIME-Version: 1.0\n");
printf("Content-Type: text/plain; charset=UTF-8\n");
/* End of headers */
printf("\n");
printf("%s\n", vmsg);
return EX_OK;
}