/src/src/exim.c

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/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) University of Cambridge 1995 - 2014 */
/* See the file NOTICE for conditions of use and distribution. */


/* The main function: entry point, initialization, and high-level control.
Also a few functions that don't naturally fit elsewhere. */


#include "exim.h"

#ifdef USE_GNUTLS
# include <gnutls/gnutls.h>
# if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP)
#  define DISABLE_OCSP
# endif
#endif

extern void init_lookup_list(void);



/*************************************************
*      Function interface to store functions     *
*************************************************/

/* We need some real functions to pass to the PCRE regular expression library
for store allocation via Exim's store manager. The normal calls are actually
macros that pass over location information to make tracing easier. These
functions just interface to the standard macro calls. A good compiler will
optimize out the tail recursion and so not make them too expensive. There
are two sets of functions; one for use when we want to retain the compiled
regular expression for a long time; the other for short-term use. */

static void *
function_store_get(size_t size)
{
return store_get((int)size);
}

static void
function_dummy_free(void *block) { block = block; }

static void *
function_store_malloc(size_t size)
{
return store_malloc((int)size);
}

static void
function_store_free(void *block)
{
store_free(block);
}




/*************************************************
*         Enums for cmdline interface            *
*************************************************/

enum commandline_info { CMDINFO_NONE=0,
  CMDINFO_HELP, CMDINFO_SIEVE, CMDINFO_DSCP };




/*************************************************
*  Compile regular expression and panic on fail  *
*************************************************/

/* This function is called when failure to compile a regular expression leads
to a panic exit. In other cases, pcre_compile() is called directly. In many
cases where this function is used, the results of the compilation are to be
placed in long-lived store, so we temporarily reset the store management
functions that PCRE uses if the use_malloc flag is set.

Argument:
  pattern     the pattern to compile
  caseless    TRUE if caseless matching is required
  use_malloc  TRUE if compile into malloc store

Returns:      pointer to the compiled pattern
*/

const pcre *
regex_must_compile(const uschar *pattern, BOOL caseless, BOOL use_malloc)
{
int offset;
int options = PCRE_COPT;
const pcre *yield;
const uschar *error;
if (use_malloc)
  {
  pcre_malloc = function_store_malloc;
  pcre_free = function_store_free;
  }
if (caseless) options |= PCRE_CASELESS;
yield = pcre_compile(CCS pattern, options, (const char **)&error, &offset, NULL);
pcre_malloc = function_store_get;
pcre_free = function_dummy_free;
if (yield == NULL)
  log_write(0, LOG_MAIN|LOG_PANIC_DIE, "regular expression error: "
    "%s at offset %d while compiling %s", error, offset, pattern);
return yield;
}




/*************************************************
*   Execute regular expression and set strings   *
*************************************************/

/* This function runs a regular expression match, and sets up the pointers to
the matched substrings.

Arguments:
  re          the compiled expression
  subject     the subject string
  options     additional PCRE options
  setup       if < 0 do full setup
              if >= 0 setup from setup+1 onwards,
                excluding the full matched string

Returns:      TRUE or FALSE
*/

BOOL
regex_match_and_setup(const pcre *re, const uschar *subject, int options, int setup)
{
int ovector[3*(EXPAND_MAXN+1)];
uschar * s = string_copy(subject);	/* de-constifying */
int n = pcre_exec(re, NULL, CS s, Ustrlen(s), 0,
  PCRE_EOPT | options, ovector, sizeof(ovector)/sizeof(int));
BOOL yield = n >= 0;
if (n == 0) n = EXPAND_MAXN + 1;
if (yield)
  {
  int nn;
  expand_nmax = (setup < 0)? 0 : setup + 1;
  for (nn = (setup < 0)? 0 : 2; nn < n*2; nn += 2)
    {
    expand_nstring[expand_nmax] = s + ovector[nn];
    expand_nlength[expand_nmax++] = ovector[nn+1] - ovector[nn];
    }
  expand_nmax--;
  }
return yield;
}




/*************************************************
*            Set up processing details           *
*************************************************/

/* Save a text string for dumping when SIGUSR1 is received.
Do checks for overruns.

Arguments: format and arguments, as for printf()
Returns:   nothing
*/

void
set_process_info(const char *format, ...)
{
int len;
va_list ap;
sprintf(CS process_info, "%5d ", (int)getpid());
len = Ustrlen(process_info);
va_start(ap, format);
if (!string_vformat(process_info + len, PROCESS_INFO_SIZE - len - 2, format, ap))
  Ustrcpy(process_info + len, "**** string overflowed buffer ****");
len = Ustrlen(process_info);
process_info[len+0] = '\n';
process_info[len+1] = '\0';
process_info_len = len + 1;
DEBUG(D_process_info) debug_printf("set_process_info: %s", process_info);
va_end(ap);
}




/*************************************************
*             Handler for SIGUSR1                *
*************************************************/

/* SIGUSR1 causes any exim process to write to the process log details of
what it is currently doing. It will only be used if the OS is capable of
setting up a handler that causes automatic restarting of any system call
that is in progress at the time.

This function takes care to be signal-safe.

Argument: the signal number (SIGUSR1)
Returns:  nothing
*/

static void
usr1_handler(int sig)
{
int fd;

os_restarting_signal(sig, usr1_handler);

fd = Uopen(process_log_path, O_APPEND|O_WRONLY, LOG_MODE);
if (fd < 0)
  {
  /* If we are already running as the Exim user, try to create it in the
  current process (assuming spool_directory exists). Otherwise, if we are
  root, do the creation in an exim:exim subprocess. */

  int euid = geteuid();
  if (euid == exim_uid)
    fd = Uopen(process_log_path, O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
  else if (euid == root_uid)
    fd = log_create_as_exim(process_log_path);
  }

/* If we are neither exim nor root, or if we failed to create the log file,
give up. There is not much useful we can do with errors, since we don't want
to disrupt whatever is going on outside the signal handler. */

if (fd < 0) return;

{int dummy = write(fd, process_info, process_info_len); dummy = dummy; }
(void)close(fd);
}



/*************************************************
*             Timeout handler                    *
*************************************************/

/* This handler is enabled most of the time that Exim is running. The handler
doesn't actually get used unless alarm() has been called to set a timer, to
place a time limit on a system call of some kind. When the handler is run, it
re-enables itself.

There are some other SIGALRM handlers that are used in special cases when more
than just a flag setting is required; for example, when reading a message's
input. These are normally set up in the code module that uses them, and the
SIGALRM handler is reset to this one afterwards.

Argument: the signal value (SIGALRM)
Returns:  nothing
*/

void
sigalrm_handler(int sig)
{
sig = sig;      /* Keep picky compilers happy */
sigalrm_seen = TRUE;
os_non_restarting_signal(SIGALRM, sigalrm_handler);
}



/*************************************************
*      Sleep for a fractional time interval      *
*************************************************/

/* This function is called by millisleep() and exim_wait_tick() to wait for a
period of time that may include a fraction of a second. The coding is somewhat
tedious. We do not expect setitimer() ever to fail, but if it does, the process
will wait for ever, so we panic in this instance. (There was a case of this
when a bug in a function that calls milliwait() caused it to pass invalid data.
That's when I added the check. :-)

We assume it to be not worth sleeping for under 100us; this value will
require revisiting as hardware advances.  This avoids the issue of
a zero-valued timer setting meaning "never fire".

Argument:  an itimerval structure containing the interval
Returns:   nothing
*/

static void
milliwait(struct itimerval *itval)
{
sigset_t sigmask;
sigset_t old_sigmask;

if (itval->it_value.tv_usec < 100 && itval->it_value.tv_sec == 0)
  return;
(void)sigemptyset(&sigmask);                           /* Empty mask */
(void)sigaddset(&sigmask, SIGALRM);                    /* Add SIGALRM */
(void)sigprocmask(SIG_BLOCK, &sigmask, &old_sigmask);  /* Block SIGALRM */
if (setitimer(ITIMER_REAL, itval, NULL) < 0)           /* Start timer */
  log_write(0, LOG_MAIN|LOG_PANIC_DIE,
    "setitimer() failed: %s", strerror(errno));
(void)sigfillset(&sigmask);                            /* All signals */
(void)sigdelset(&sigmask, SIGALRM);                    /* Remove SIGALRM */
(void)sigsuspend(&sigmask);                            /* Until SIGALRM */
(void)sigprocmask(SIG_SETMASK, &old_sigmask, NULL);    /* Restore mask */
}




/*************************************************
*         Millisecond sleep function             *
*************************************************/

/* The basic sleep() function has a granularity of 1 second, which is too rough
in some cases - for example, when using an increasing delay to slow down
spammers.

Argument:    number of millseconds
Returns:     nothing
*/

void
millisleep(int msec)
{
struct itimerval itval;
itval.it_interval.tv_sec = 0;
itval.it_interval.tv_usec = 0;
itval.it_value.tv_sec = msec/1000;
itval.it_value.tv_usec = (msec % 1000) * 1000;
milliwait(&itval);
}



/*************************************************
*         Compare microsecond times              *
*************************************************/

/*
Arguments:
  tv1         the first time
  tv2         the second time

Returns:      -1, 0, or +1
*/

int
exim_tvcmp(struct timeval *t1, struct timeval *t2)
{
if (t1->tv_sec > t2->tv_sec) return +1;
if (t1->tv_sec < t2->tv_sec) return -1;
if (t1->tv_usec > t2->tv_usec) return +1;
if (t1->tv_usec < t2->tv_usec) return -1;
return 0;
}




/*************************************************
*          Clock tick wait function              *
*************************************************/

/* Exim uses a time + a pid to generate a unique identifier in two places: its
message IDs, and in file names for maildir deliveries. Because some OS now
re-use pids within the same second, sub-second times are now being used.
However, for absolute certaintly, we must ensure the clock has ticked before
allowing the relevant process to complete. At the time of implementation of
this code (February 2003), the speed of processors is such that the clock will
invariably have ticked already by the time a process has done its job. This
function prepares for the time when things are faster - and it also copes with
clocks that go backwards.

Arguments:
  then_tv      A timeval which was used to create uniqueness; its usec field
                 has been rounded down to the value of the resolution.
                 We want to be sure the current time is greater than this.
  resolution   The resolution that was used to divide the microseconds
                 (1 for maildir, larger for message ids)

Returns:       nothing
*/

void
exim_wait_tick(struct timeval *then_tv, int resolution)
{
struct timeval now_tv;
long int now_true_usec;

(void)gettimeofday(&now_tv, NULL);
now_true_usec = now_tv.tv_usec;
now_tv.tv_usec = (now_true_usec/resolution) * resolution;

if (exim_tvcmp(&now_tv, then_tv) <= 0)
  {
  struct itimerval itval;
  itval.it_interval.tv_sec = 0;
  itval.it_interval.tv_usec = 0;
  itval.it_value.tv_sec = then_tv->tv_sec - now_tv.tv_sec;
  itval.it_value.tv_usec = then_tv->tv_usec + resolution - now_true_usec;

  /* We know that, overall, "now" is less than or equal to "then". Therefore, a
  negative value for the microseconds is possible only in the case when "now"
  is more than a second less than "then". That means that itval.it_value.tv_sec
  is greater than zero. The following correction is therefore safe. */

  if (itval.it_value.tv_usec < 0)
    {
    itval.it_value.tv_usec += 1000000;
    itval.it_value.tv_sec -= 1;
    }

  DEBUG(D_transport|D_receive)
    {
    if (!running_in_test_harness)
      {
      debug_printf("tick check: " TIME_T_FMT ".%06lu " TIME_T_FMT ".%06lu\n",
        then_tv->tv_sec, (long) then_tv->tv_usec,
       	now_tv.tv_sec, (long) now_tv.tv_usec);
      debug_printf("waiting " TIME_T_FMT ".%06lu\n",
        itval.it_value.tv_sec, (long) itval.it_value.tv_usec);
      }
    }

  milliwait(&itval);
  }
}




/*************************************************
*   Call fopen() with umask 777 and adjust mode  *
*************************************************/

/* Exim runs with umask(0) so that files created with open() have the mode that
is specified in the open() call. However, there are some files, typically in
the spool directory, that are created with fopen(). They end up world-writeable
if no precautions are taken. Although the spool directory is not accessible to
the world, this is an untidiness. So this is a wrapper function for fopen()
that sorts out the mode of the created file.

Arguments:
   filename       the file name
   options        the fopen() options
   mode           the required mode

Returns:          the fopened FILE or NULL
*/

FILE *
modefopen(const uschar *filename, const char *options, mode_t mode)
{
mode_t saved_umask = umask(0777);
FILE *f = Ufopen(filename, options);
(void)umask(saved_umask);
if (f != NULL) (void)fchmod(fileno(f), mode);
return f;
}




/*************************************************
*   Ensure stdin, stdout, and stderr exist       *
*************************************************/

/* Some operating systems grumble if an exec() happens without a standard
input, output, and error (fds 0, 1, 2) being defined. The worry is that some
file will be opened and will use these fd values, and then some other bit of
code will assume, for example, that it can write error messages to stderr.
This function ensures that fds 0, 1, and 2 are open if they do not already
exist, by connecting them to /dev/null.

This function is also used to ensure that std{in,out,err} exist at all times,
so that if any library that Exim calls tries to use them, it doesn't crash.

Arguments:  None
Returns:    Nothing
*/

void
exim_nullstd(void)
{
int i;
int devnull = -1;
struct stat statbuf;
for (i = 0; i <= 2; i++)
  {
  if (fstat(i, &statbuf) < 0 && errno == EBADF)
    {
    if (devnull < 0) devnull = open("/dev/null", O_RDWR);
    if (devnull < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
      string_open_failed(errno, "/dev/null"));
    if (devnull != i) (void)dup2(devnull, i);
    }
  }
if (devnull > 2) (void)close(devnull);
}




/*************************************************
*   Close unwanted file descriptors for delivery *
*************************************************/

/* This function is called from a new process that has been forked to deliver
an incoming message, either directly, or using exec.

We want any smtp input streams to be closed in this new process. However, it
has been observed that using fclose() here causes trouble. When reading in -bS
input, duplicate copies of messages have been seen. The files will be sharing a
file pointer with the parent process, and it seems that fclose() (at least on
some systems - I saw this on Solaris 2.5.1) messes with that file pointer, at
least sometimes. Hence we go for closing the underlying file descriptors.

If TLS is active, we want to shut down the TLS library, but without molesting
the parent's SSL connection.

For delivery of a non-SMTP message, we want to close stdin and stdout (and
stderr unless debugging) because the calling process might have set them up as
pipes and be waiting for them to close before it waits for the submission
process to terminate. If they aren't closed, they hold up the calling process
until the initial delivery process finishes, which is not what we want.

Exception: We do want it for synchronous delivery!

And notwithstanding all the above, if D_resolver is set, implying resolver
debugging, leave stdout open, because that's where the resolver writes its
debugging output.

When we close stderr (which implies we've also closed stdout), we also get rid
of any controlling terminal.

Arguments:   None
Returns:     Nothing
*/

static void
close_unwanted(void)
{
if (smtp_input)
  {
  #ifdef SUPPORT_TLS
  tls_close(TRUE, FALSE);      /* Shut down the TLS library */
  #endif
  (void)close(fileno(smtp_in));
  (void)close(fileno(smtp_out));
  smtp_in = NULL;
  }
else
  {
  (void)close(0);                                          /* stdin */
  if ((debug_selector & D_resolver) == 0) (void)close(1);  /* stdout */
  if (debug_selector == 0)                                 /* stderr */
    {
    if (!synchronous_delivery)
      {
      (void)close(2);
      log_stderr = NULL;
      }
    (void)setsid();
    }
  }
}




/*************************************************
*          Set uid and gid                       *
*************************************************/

/* This function sets a new uid and gid permanently, optionally calling
initgroups() to set auxiliary groups. There are some special cases when running
Exim in unprivileged modes. In these situations the effective uid will not be
root; if we already have the right effective uid/gid, and don't need to
initialize any groups, leave things as they are.

Arguments:
  uid        the uid
  gid        the gid
  igflag     TRUE if initgroups() wanted
  msg        text to use in debugging output and failure log

Returns:     nothing; bombs out on failure
*/

void
exim_setugid(uid_t uid, gid_t gid, BOOL igflag, uschar *msg)
{
uid_t euid = geteuid();
gid_t egid = getegid();

if (euid == root_uid || euid != uid || egid != gid || igflag)
  {
  /* At least one OS returns +1 for initgroups failure, so just check for
  non-zero. */

  if (igflag)
    {
    struct passwd *pw = getpwuid(uid);
    if (pw != NULL)
      {
      if (initgroups(pw->pw_name, gid) != 0)
        log_write(0,LOG_MAIN|LOG_PANIC_DIE,"initgroups failed for uid=%ld: %s",
          (long int)uid, strerror(errno));
      }
    else log_write(0, LOG_MAIN|LOG_PANIC_DIE, "cannot run initgroups(): "
      "no passwd entry for uid=%ld", (long int)uid);
    }

  if (setgid(gid) < 0 || setuid(uid) < 0)
    {
    log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to set gid=%ld or uid=%ld "
      "(euid=%ld): %s", (long int)gid, (long int)uid, (long int)euid, msg);
    }
  }

/* Debugging output included uid/gid and all groups */

DEBUG(D_uid)
  {
  int group_count, save_errno;
  gid_t group_list[NGROUPS_MAX];
  debug_printf("changed uid/gid: %s\n  uid=%ld gid=%ld pid=%ld\n", msg,
    (long int)geteuid(), (long int)getegid(), (long int)getpid());
  group_count = getgroups(NGROUPS_MAX, group_list);
  save_errno = errno;
  debug_printf("  auxiliary group list:");
  if (group_count > 0)
    {
    int i;
    for (i = 0; i < group_count; i++) debug_printf(" %d", (int)group_list[i]);
    }
  else if (group_count < 0)
    debug_printf(" <error: %s>", strerror(save_errno));
  else debug_printf(" <none>");
  debug_printf("\n");
  }
}




/*************************************************
*               Exit point                       *
*************************************************/

/* Exim exits via this function so that it always clears up any open
databases.

Arguments:
  rc         return code

Returns:     does not return
*/

void
exim_exit(int rc)
{
search_tidyup();
DEBUG(D_any)
  debug_printf(">>>>>>>>>>>>>>>> Exim pid=%d terminating with rc=%d "
    ">>>>>>>>>>>>>>>>\n", (int)getpid(), rc);
exit(rc);
}




/*************************************************
*         Extract port from host address         *
*************************************************/

/* Called to extract the port from the values given to -oMa and -oMi.
It also checks the syntax of the address, and terminates it before the
port data when a port is extracted.

Argument:
  address   the address, with possible port on the end

Returns:    the port, or zero if there isn't one
            bombs out on a syntax error
*/

static int
check_port(uschar *address)
{
int port = host_address_extract_port(address);
if (string_is_ip_address(address, NULL) == 0)
  {
  fprintf(stderr, "exim abandoned: \"%s\" is not an IP address\n", address);
  exit(EXIT_FAILURE);
  }
return port;
}



/*************************************************
*              Test/verify an address            *
*************************************************/

/* This function is called by the -bv and -bt code. It extracts a working
address from a full RFC 822 address. This isn't really necessary per se, but it
has the effect of collapsing source routes.

Arguments:
  s            the address string
  flags        flag bits for verify_address()
  exit_value   to be set for failures

Returns:       nothing
*/

static void
test_address(uschar *s, int flags, int *exit_value)
{
int start, end, domain;
uschar *parse_error = NULL;
uschar *address = parse_extract_address(s, &parse_error, &start, &end, &domain,
  FALSE);
if (address == NULL)
  {
  fprintf(stdout, "syntax error: %s\n", parse_error);
  *exit_value = 2;
  }
else
  {
  int rc = verify_address(deliver_make_addr(address,TRUE), stdout, flags, -1,
    -1, -1, NULL, NULL, NULL);
  if (rc == FAIL) *exit_value = 2;
    else if (rc == DEFER && *exit_value == 0) *exit_value = 1;
  }
}



/*************************************************
*          Show supported features               *
*************************************************/

/* This function is called for -bV/--version and for -d to output the optional
features of the current Exim binary.

Arguments:  a FILE for printing
Returns:    nothing
*/

static void
show_whats_supported(FILE *f)
{
  auth_info *authi;

#ifdef DB_VERSION_STRING
fprintf(f, "Berkeley DB: %s\n", DB_VERSION_STRING);
#elif defined(BTREEVERSION) && defined(HASHVERSION)
  #ifdef USE_DB
  fprintf(f, "Probably Berkeley DB version 1.8x (native mode)\n");
  #else
  fprintf(f, "Probably Berkeley DB version 1.8x (compatibility mode)\n");
  #endif
#elif defined(_DBM_RDONLY) || defined(dbm_dirfno)
fprintf(f, "Probably ndbm\n");
#elif defined(USE_TDB)
fprintf(f, "Using tdb\n");
#else
  #ifdef USE_GDBM
  fprintf(f, "Probably GDBM (native mode)\n");
  #else
  fprintf(f, "Probably GDBM (compatibility mode)\n");
  #endif
#endif

fprintf(f, "Support for:");
#ifdef SUPPORT_CRYPTEQ
  fprintf(f, " crypteq");
#endif
#if HAVE_ICONV
  fprintf(f, " iconv()");
#endif
#if HAVE_IPV6
  fprintf(f, " IPv6");
#endif
#ifdef HAVE_SETCLASSRESOURCES
  fprintf(f, " use_setclassresources");
#endif
#ifdef SUPPORT_PAM
  fprintf(f, " PAM");
#endif
#ifdef EXIM_PERL
  fprintf(f, " Perl");
#endif
#ifdef EXPAND_DLFUNC
  fprintf(f, " Expand_dlfunc");
#endif
#ifdef USE_TCP_WRAPPERS
  fprintf(f, " TCPwrappers");
#endif
#ifdef SUPPORT_TLS
  #ifdef USE_GNUTLS
  fprintf(f, " GnuTLS");
  #else
  fprintf(f, " OpenSSL");
  #endif
#endif
#ifdef SUPPORT_TRANSLATE_IP_ADDRESS
  fprintf(f, " translate_ip_address");
#endif
#ifdef SUPPORT_MOVE_FROZEN_MESSAGES
  fprintf(f, " move_frozen_messages");
#endif
#ifdef WITH_CONTENT_SCAN
  fprintf(f, " Content_Scanning");
#endif
#ifndef DISABLE_DKIM
  fprintf(f, " DKIM");
#endif
#ifdef WITH_OLD_DEMIME
  fprintf(f, " Old_Demime");
#endif
#ifndef DISABLE_DNSSEC
  fprintf(f, " DNSSEC");
#endif
#ifndef DISABLE_PRDR
  fprintf(f, " PRDR");
#endif
#ifndef DISABLE_OCSP
  fprintf(f, " OCSP");
#endif
#ifdef EXPERIMENTAL_SPF
  fprintf(f, " Experimental_SPF");
#endif
#ifdef EXPERIMENTAL_SRS
  fprintf(f, " Experimental_SRS");
#endif
#ifdef EXPERIMENTAL_BRIGHTMAIL
  fprintf(f, " Experimental_Brightmail");
#endif
#ifdef EXPERIMENTAL_DANE
  fprintf(f, " Experimental_DANE");
#endif
#ifdef EXPERIMENTAL_DCC
  fprintf(f, " Experimental_DCC");
#endif
#ifdef EXPERIMENTAL_DMARC
  fprintf(f, " Experimental_DMARC");
#endif
#ifdef EXPERIMENTAL_PROXY
  fprintf(f, " Experimental_Proxy");
#endif
#ifdef EXPERIMENTAL_EVENT
  fprintf(f, " Experimental_Event");
#endif
#ifdef EXPERIMENTAL_REDIS
  fprintf(f, " Experimental_Redis");
#endif
#ifdef EXPERIMENTAL_SOCKS
  fprintf(f, " Experimental_SOCKS");
#endif
#ifdef EXPERIMENTAL_INTERNATIONAL
  fprintf(f, " Experimental_International");
#endif
fprintf(f, "\n");

fprintf(f, "Lookups (built-in):");
#if defined(LOOKUP_LSEARCH) && LOOKUP_LSEARCH!=2
  fprintf(f, " lsearch wildlsearch nwildlsearch iplsearch");
#endif
#if defined(LOOKUP_CDB) && LOOKUP_CDB!=2
  fprintf(f, " cdb");
#endif
#if defined(LOOKUP_DBM) && LOOKUP_DBM!=2
  fprintf(f, " dbm dbmjz dbmnz");
#endif
#if defined(LOOKUP_DNSDB) && LOOKUP_DNSDB!=2
  fprintf(f, " dnsdb");
#endif
#if defined(LOOKUP_DSEARCH) && LOOKUP_DSEARCH!=2
  fprintf(f, " dsearch");
#endif
#if defined(LOOKUP_IBASE) && LOOKUP_IBASE!=2
  fprintf(f, " ibase");
#endif
#if defined(LOOKUP_LDAP) && LOOKUP_LDAP!=2
  fprintf(f, " ldap ldapdn ldapm");
#endif
#if defined(LOOKUP_MYSQL) && LOOKUP_MYSQL!=2
  fprintf(f, " mysql");
#endif
#if defined(LOOKUP_NIS) && LOOKUP_NIS!=2
  fprintf(f, " nis nis0");
#endif
#if defined(LOOKUP_NISPLUS) && LOOKUP_NISPLUS!=2
  fprintf(f, " nisplus");
#endif
#if defined(LOOKUP_ORACLE) && LOOKUP_ORACLE!=2
  fprintf(f, " oracle");
#endif
#if defined(LOOKUP_PASSWD) && LOOKUP_PASSWD!=2
  fprintf(f, " passwd");
#endif
#if defined(LOOKUP_PGSQL) && LOOKUP_PGSQL!=2
  fprintf(f, " pgsql");
#endif
#if defined(LOOKUP_SQLITE) && LOOKUP_SQLITE!=2
  fprintf(f, " sqlite");
#endif
#if defined(LOOKUP_TESTDB) && LOOKUP_TESTDB!=2
  fprintf(f, " testdb");
#endif
#if defined(LOOKUP_WHOSON) && LOOKUP_WHOSON!=2
  fprintf(f, " whoson");
#endif
fprintf(f, "\n");

fprintf(f, "Authenticators:");
#ifdef AUTH_CRAM_MD5
  fprintf(f, " cram_md5");
#endif
#ifdef AUTH_CYRUS_SASL
  fprintf(f, " cyrus_sasl");
#endif
#ifdef AUTH_DOVECOT
  fprintf(f, " dovecot");
#endif
#ifdef AUTH_GSASL
  fprintf(f, " gsasl");
#endif
#ifdef AUTH_HEIMDAL_GSSAPI
  fprintf(f, " heimdal_gssapi");
#endif
#ifdef AUTH_PLAINTEXT
  fprintf(f, " plaintext");
#endif
#ifdef AUTH_SPA
  fprintf(f, " spa");
#endif
fprintf(f, "\n");

fprintf(f, "Routers:");
#ifdef ROUTER_ACCEPT
  fprintf(f, " accept");
#endif
#ifdef ROUTER_DNSLOOKUP
  fprintf(f, " dnslookup");
#endif
#ifdef ROUTER_IPLITERAL
  fprintf(f, " ipliteral");
#endif
#ifdef ROUTER_IPLOOKUP
  fprintf(f, " iplookup");
#endif
#ifdef ROUTER_MANUALROUTE
  fprintf(f, " manualroute");
#endif
#ifdef ROUTER_QUERYPROGRAM
  fprintf(f, " queryprogram");
#endif
#ifdef ROUTER_REDIRECT
  fprintf(f, " redirect");
#endif
fprintf(f, "\n");

fprintf(f, "Transports:");
#ifdef TRANSPORT_APPENDFILE
  fprintf(f, " appendfile");
  #ifdef SUPPORT_MAILDIR
    fprintf(f, "/maildir");
  #endif
  #ifdef SUPPORT_MAILSTORE
    fprintf(f, "/mailstore");
  #endif
  #ifdef SUPPORT_MBX
    fprintf(f, "/mbx");
  #endif
#endif
#ifdef TRANSPORT_AUTOREPLY
  fprintf(f, " autoreply");
#endif
#ifdef TRANSPORT_LMTP
  fprintf(f, " lmtp");
#endif
#ifdef TRANSPORT_PIPE
  fprintf(f, " pipe");
#endif
#ifdef TRANSPORT_SMTP
  fprintf(f, " smtp");
#endif
fprintf(f, "\n");

if (fixed_never_users[0] > 0)
  {
  int i;
  fprintf(f, "Fixed never_users: ");
  for (i = 1; i <= (int)fixed_never_users[0] - 1; i++)
    fprintf(f, "%d:", (unsigned int)fixed_never_users[i]);
  fprintf(f, "%d\n", (unsigned int)fixed_never_users[i]);
  }

fprintf(f, "Size of off_t: " SIZE_T_FMT "\n", sizeof(off_t));

/* Everything else is details which are only worth reporting when debugging.
Perhaps the tls_version_report should move into this too. */
DEBUG(D_any) do {

  int i;

/* clang defines __GNUC__ (at least, for me) so test for it first */
#if defined(__clang__)
  fprintf(f, "Compiler: CLang [%s]\n", __clang_version__);
#elif defined(__GNUC__)
  fprintf(f, "Compiler: GCC [%s]\n",
# ifdef __VERSION__
      __VERSION__
# else
      "? unknown version ?"
# endif
      );
#else
  fprintf(f, "Compiler: <unknown>\n");
#endif

#ifdef SUPPORT_TLS
  tls_version_report(f);
#endif
#ifdef EXPERIMENTAL_INTERNATIONAL
  utf8_version_report(f);
#endif

  for (authi = auths_available; *authi->driver_name != '\0'; ++authi)
    if (authi->version_report)
      (*authi->version_report)(f);

  /* PCRE_PRERELEASE is either defined and empty or a bare sequence of
  characters; unless it's an ancient version of PCRE in which case it
  is not defined. */
#ifndef PCRE_PRERELEASE
#define PCRE_PRERELEASE
#endif
#define QUOTE(X) #X
#define EXPAND_AND_QUOTE(X) QUOTE(X)
  fprintf(f, "Library version: PCRE: Compile: %d.%d%s\n"
             "                       Runtime: %s\n",
          PCRE_MAJOR, PCRE_MINOR,
          EXPAND_AND_QUOTE(PCRE_PRERELEASE) "",
          pcre_version());
#undef QUOTE
#undef EXPAND_AND_QUOTE

  init_lookup_list();
  for (i = 0; i < lookup_list_count; i++)
    if (lookup_list[i]->version_report)
      lookup_list[i]->version_report(f);

#ifdef WHITELIST_D_MACROS
  fprintf(f, "WHITELIST_D_MACROS: \"%s\"\n", WHITELIST_D_MACROS);
#else
  fprintf(f, "WHITELIST_D_MACROS unset\n");
#endif
#ifdef TRUSTED_CONFIG_LIST
  fprintf(f, "TRUSTED_CONFIG_LIST: \"%s\"\n", TRUSTED_CONFIG_LIST);
#else
  fprintf(f, "TRUSTED_CONFIG_LIST unset\n");
#endif

} while (0);
}


/*************************************************
*     Show auxiliary information about Exim      *
*************************************************/

static void
show_exim_information(enum commandline_info request, FILE *stream)
{
const uschar **pp;

switch(request)
  {
  case CMDINFO_NONE:
    fprintf(stream, "Oops, something went wrong.\n");
    return;
  case CMDINFO_HELP:
    fprintf(stream,
"The -bI: flag takes a string indicating which information to provide.\n"
"If the string is not recognised, you'll get this help (on stderr).\n"
"\n"
"  exim -bI:help    this information\n"
"  exim -bI:dscp    dscp value keywords known\n"
"  exim -bI:sieve   list of supported sieve extensions, one per line.\n"
);
    return;
  case CMDINFO_SIEVE:
    for (pp = exim_sieve_extension_list; *pp; ++pp)
      fprintf(stream, "%s\n", *pp);
    return;
  case CMDINFO_DSCP:
    dscp_list_to_stream(stream);
    return;
  }
}


/*************************************************
*               Quote a local part               *
*************************************************/

/* This function is used when a sender address or a From: or Sender: header
line is being created from the caller's login, or from an authenticated_id. It
applies appropriate quoting rules for a local part.

Argument:    the local part
Returns:     the local part, quoted if necessary
*/

uschar *
local_part_quote(uschar *lpart)
{
BOOL needs_quote = FALSE;
int size, ptr;
uschar *yield;
uschar *t;

for (t = lpart; !needs_quote && *t != 0; t++)
  {
  needs_quote = !isalnum(*t) && strchr("!#$%&'*+-/=?^_`{|}~", *t) == NULL &&
    (*t != '.' || t == lpart || t[1] == 0);
  }

if (!needs_quote) return lpart;

size = ptr = 0;
yield = string_cat(NULL, &size, &ptr, US"\"", 1);

for (;;)
  {
  uschar *nq = US Ustrpbrk(lpart, "\\\"");
  if (nq == NULL)
    {
    yield = string_cat(yield, &size, &ptr, lpart, Ustrlen(lpart));
    break;
    }
  yield = string_cat(yield, &size, &ptr, lpart, nq - lpart);
  yield = string_cat(yield, &size, &ptr, US"\\", 1);
  yield = string_cat(yield, &size, &ptr, nq, 1);
  lpart = nq + 1;
  }

yield = string_cat(yield, &size, &ptr, US"\"", 1);
yield[ptr] = 0;
return yield;
}



#ifdef USE_READLINE
/*************************************************
*         Load readline() functions              *
*************************************************/

/* This function is called from testing executions that read data from stdin,
but only when running as the calling user. Currently, only -be does this. The
function loads the readline() function library and passes back the functions.
On some systems, it needs the curses library, so load that too, but try without
it if loading fails. All this functionality has to be requested at build time.

Arguments:
  fn_readline_ptr   pointer to where to put the readline pointer
  fn_addhist_ptr    pointer to where to put the addhistory function

Returns:            the dlopen handle or NULL on failure
*/

static void *
set_readline(char * (**fn_readline_ptr)(const char *),
             void   (**fn_addhist_ptr)(const char *))
{
void *dlhandle;
void *dlhandle_curses = dlopen("libcurses." DYNLIB_FN_EXT, RTLD_GLOBAL|RTLD_LAZY);

dlhandle = dlopen("libreadline." DYNLIB_FN_EXT, RTLD_GLOBAL|RTLD_NOW);
if (dlhandle_curses != NULL) dlclose(dlhandle_curses);

if (dlhandle != NULL)
  {
  /* Checked manual pages; at least in GNU Readline 6.1, the prototypes are:
   *   char * readline (const char *prompt);
   *   void add_history (const char *string);
   */
  *fn_readline_ptr = (char *(*)(const char*))dlsym(dlhandle, "readline");
  *fn_addhist_ptr = (void(*)(const char*))dlsym(dlhandle, "add_history");
  }
else
  {
  DEBUG(D_any) debug_printf("failed to load readline: %s\n", dlerror());
  }

return dlhandle;
}
#endif



/*************************************************
*    Get a line from stdin for testing things    *
*************************************************/

/* This function is called when running tests that can take a number of lines
of input (for example, -be and -bt). It handles continuations and trailing
spaces. And prompting and a blank line output on eof. If readline() is in use,
the arguments are non-NULL and provide the relevant functions.

Arguments:
  fn_readline   readline function or NULL
  fn_addhist    addhist function or NULL

Returns:        pointer to dynamic memory, or NULL at end of file
*/

static uschar *
get_stdinput(char *(*fn_readline)(const char *), void(*fn_addhist)(const char *))
{
int i;
int size = 0;
int ptr = 0;
uschar *yield = NULL;

if (fn_readline == NULL) { printf("> "); fflush(stdout); }

for (i = 0;; i++)
  {
  uschar buffer[1024];
  uschar *p, *ss;

  #ifdef USE_READLINE
  char *readline_line = NULL;
  if (fn_readline != NULL)
    {
    if ((readline_line = fn_readline((i > 0)? "":"> ")) == NULL) break;
    if (*readline_line != 0 && fn_addhist != NULL) fn_addhist(readline_line);
    p = US readline_line;
    }
  else
  #endif

  /* readline() not in use */

    {
    if (Ufgets(buffer, sizeof(buffer), stdin) == NULL) break;
    p = buffer;
    }

  /* Handle the line */

  ss = p + (int)Ustrlen(p);
  while (ss > p && isspace(ss[-1])) ss--;

  if (i > 0)
    {
    while (p < ss && isspace(*p)) p++;   /* leading space after cont */
    }

  yield = string_cat(yield, &size, &ptr, p, ss - p);

  #ifdef USE_READLINE
  if (fn_readline != NULL) free(readline_line);
  #endif

  if (ss == p || yield[ptr-1] != '\\')
    {
    yield[ptr] = 0;
    break;
    }
  yield[--ptr] = 0;
  }

if (yield == NULL) printf("\n");
return yield;
}



/*************************************************
*    Output usage information for the program    *
*************************************************/

/* This function is called when there are no recipients
   or a specific --help argument was added.

Arguments:
  progname      information on what name we were called by

Returns:        DOES NOT RETURN
*/

static void
exim_usage(uschar *progname)
{

/* Handle specific program invocation varients */
if (Ustrcmp(progname, US"-mailq") == 0)
  {
  fprintf(stderr,
    "mailq - list the contents of the mail queue\n\n"
    "For a list of options, see the Exim documentation.\n");
  exit(EXIT_FAILURE);
  }

/* Generic usage - we output this whatever happens */
fprintf(stderr,
  "Exim is a Mail Transfer Agent. It is normally called by Mail User Agents,\n"
  "not directly from a shell command line. Options and/or arguments control\n"
  "what it does when called. For a list of options, see the Exim documentation.\n");

exit(EXIT_FAILURE);
}



/*************************************************
*    Validate that the macros given are okay     *
*************************************************/

/* Typically, Exim will drop privileges if macros are supplied.  In some
cases, we want to not do so.

Arguments:    none (macros is a global)
Returns:      true if trusted, false otherwise
*/

static BOOL
macros_trusted(void)
{
#ifdef WHITELIST_D_MACROS
macro_item *m;
uschar *whitelisted, *end, *p, **whites, **w;
int white_count, i, n;
size_t len;
BOOL prev_char_item, found;
#endif

if (macros == NULL)
  return TRUE;
#ifndef WHITELIST_D_MACROS
return FALSE;
#else

/* We only trust -D overrides for some invoking users:
root, the exim run-time user, the optional config owner user.
I don't know why config-owner would be needed, but since they can own the
config files anyway, there's no security risk to letting them override -D. */
if ( ! ((real_uid == root_uid)
     || (real_uid == exim_uid)
#ifdef CONFIGURE_OWNER
     || (real_uid == config_uid)
#endif
   ))
  {
  debug_printf("macros_trusted rejecting macros for uid %d\n", (int) real_uid);
  return FALSE;
  }

/* Get a list of macros which are whitelisted */
whitelisted = string_copy_malloc(US WHITELIST_D_MACROS);
prev_char_item = FALSE;
white_count = 0;
for (p = whitelisted; *p != '\0'; ++p)
  {
  if (*p == ':' || isspace(*p))
    {
    *p = '\0';
    if (prev_char_item)
      ++white_count;
    prev_char_item = FALSE;
    continue;
    }
  if (!prev_char_item)
    prev_char_item = TRUE;
  }
end = p;
if (prev_char_item)
  ++white_count;
if (!white_count)
  return FALSE;
whites = store_malloc(sizeof(uschar *) * (white_count+1));
for (p = whitelisted, i = 0; (p != end) && (i < white_count); ++p)
  {
  if (*p != '\0')
    {
    whites[i++] = p;
    if (i == white_count)
      break;
    while (*p != '\0' && p < end)
      ++p;
    }
  }
whites[i] = NULL;

/* The list of macros should be very short.  Accept the N*M complexity. */
for (m = macros; m != NULL; m = m->next)
  {
  found = FALSE;
  for (w = whites; *w; ++w)
    if (Ustrcmp(*w, m->name) == 0)
      {
      found = TRUE;
      break;
      }
  if (!found)
    return FALSE;
  if (m->replacement == NULL)
    continue;
  len = Ustrlen(m->replacement);
  if (len == 0)
    continue;
  n = pcre_exec(regex_whitelisted_macro, NULL, CS m->replacement, len,
   0, PCRE_EOPT, NULL, 0);
  if (n < 0)
    {
    if (n != PCRE_ERROR_NOMATCH)
      debug_printf("macros_trusted checking %s returned %d\n", m->name, n);
    return FALSE;
    }
  }
DEBUG(D_any) debug_printf("macros_trusted overridden to true by whitelisting\n");
return TRUE;
#endif
}


/*************************************************
*          Entry point and high-level code       *
*************************************************/

/* Entry point for the Exim mailer. Analyse the arguments and arrange to take
the appropriate action. All the necessary functions are present in the one
binary. I originally thought one should split it up, but it turns out that so
much of the apparatus is needed in each chunk that one might as well just have
it all available all the time, which then makes the coding easier as well.

Arguments:
  argc      count of entries in argv
  argv      argument strings, with argv[0] being the program name

Returns:    EXIT_SUCCESS if terminated successfully
            EXIT_FAILURE otherwise, except when a message has been sent
              to the sender, and -oee was given
*/

int
main(int argc, char **cargv)
{
uschar **argv = USS cargv;
int  arg_receive_timeout = -1;
int  arg_smtp_receive_timeout = -1;
int  arg_error_handling = error_handling;
int  filter_sfd = -1;
int  filter_ufd = -1;
int  group_count;
int  i, rv;
int  list_queue_option = 0;
int  msg_action = 0;
int  msg_action_arg = -1;
int  namelen = (argv[0] == NULL)? 0 : Ustrlen(argv[0]);
int  queue_only_reason = 0;
#ifdef EXIM_PERL
int  perl_start_option = 0;
#endif
int  recipients_arg = argc;
int  sender_address_domain = 0;
int  test_retry_arg = -1;
int  test_rewrite_arg = -1;
BOOL arg_queue_only = FALSE;
BOOL bi_option = FALSE;
BOOL checking = FALSE;
BOOL count_queue = FALSE;
BOOL expansion_test = FALSE;
BOOL extract_recipients = FALSE;
BOOL flag_G = FALSE;
BOOL flag_n = FALSE;
BOOL forced_delivery = FALSE;
BOOL f_end_dot = FALSE;
BOOL deliver_give_up = FALSE;
BOOL list_queue = FALSE;
BOOL list_options = FALSE;
BOOL local_queue_only;
BOOL more = TRUE;
BOOL one_msg_action = FALSE;
BOOL queue_only_set = FALSE;
BOOL receiving_message = TRUE;
BOOL sender_ident_set = FALSE;
BOOL session_local_queue_only;
BOOL unprivileged;
BOOL removed_privilege = FALSE;
BOOL usage_wanted = FALSE;
BOOL verify_address_mode = FALSE;
BOOL verify_as_sender = FALSE;
BOOL version_printed = FALSE;
uschar *alias_arg = NULL;
uschar *called_as = US"";
uschar *cmdline_syslog_name = NULL;
uschar *start_queue_run_id = NULL;
uschar *stop_queue_run_id = NULL;
uschar *expansion_test_message = NULL;
uschar *ftest_domain = NULL;
uschar *ftest_localpart = NULL;
uschar *ftest_prefix = NULL;
uschar *ftest_suffix = NULL;
uschar *log_oneline = NULL;
uschar *malware_test_file = NULL;
uschar *real_sender_address;
uschar *originator_home = US"/";
size_t sz;
void *reset_point;

struct passwd *pw;
struct stat statbuf;
pid_t passed_qr_pid = (pid_t)0;
int passed_qr_pipe = -1;
gid_t group_list[NGROUPS_MAX];

/* For the -bI: flag */
enum commandline_info info_flag = CMDINFO_NONE;
BOOL info_stdout = FALSE;

/* Possible options for -R and -S */

static uschar *rsopts[] = { US"f", US"ff", US"r", US"rf", US"rff" };

/* Need to define this in case we need to change the environment in order
to get rid of a bogus time zone. We have to make it char rather than uschar
because some OS define it in /usr/include/unistd.h. */

extern char **environ;

/* If the Exim user and/or group and/or the configuration file owner/group were
defined by ref:name at build time, we must now find the actual uid/gid values.
This is a feature to make the lives of binary distributors easier. */

#ifdef EXIM_USERNAME
if (route_finduser(US EXIM_USERNAME, &pw, &exim_uid))
  {
  if (exim_uid == 0)
    {
    fprintf(stderr, "exim: refusing to run with uid 0 for \"%s\"\n",
      EXIM_USERNAME);
    exit(EXIT_FAILURE);
    }
  /* If ref:name uses a number as the name, route_finduser() returns
  TRUE with exim_uid set and pw coerced to NULL. */
  if (pw)
    exim_gid = pw->pw_gid;
#ifndef EXIM_GROUPNAME
  else
    {
    fprintf(stderr,
        "exim: ref:name should specify a usercode, not a group.\n"
        "exim: can't let you get away with it unless you also specify a group.\n");
    exit(EXIT_FAILURE);
    }
#endif
  }
else
  {
  fprintf(stderr, "exim: failed to find uid for user name \"%s\"\n",
    EXIM_USERNAME);
  exit(EXIT_FAILURE);
  }
#endif

#ifdef EXIM_GROUPNAME
if (!route_findgroup(US EXIM_GROUPNAME, &exim_gid))
  {
  fprintf(stderr, "exim: failed to find gid for group name \"%s\"\n",
    EXIM_GROUPNAME);
  exit(EXIT_FAILURE);
  }
#endif

#ifdef CONFIGURE_OWNERNAME
if (!route_finduser(US CONFIGURE_OWNERNAME, NULL, &config_uid))
  {
  fprintf(stderr, "exim: failed to find uid for user name \"%s\"\n",
    CONFIGURE_OWNERNAME);
  exit(EXIT_FAILURE);
  }
#endif

/* We default the system_filter_user to be the Exim run-time user, as a
sane non-root value. */
system_filter_uid = exim_uid;

#ifdef CONFIGURE_GROUPNAME
if (!route_findgroup(US CONFIGURE_GROUPNAME, &config_gid))
  {
  fprintf(stderr, "exim: failed to find gid for group name \"%s\"\n",
    CONFIGURE_GROUPNAME);
  exit(EXIT_FAILURE);
  }
#endif

/* In the Cygwin environment, some initialization needs doing. It is fudged
in by means of this macro. */

#ifdef OS_INIT
OS_INIT
#endif

/* Check a field which is patched when we are running Exim within its
testing harness; do a fast initial check, and then the whole thing. */

running_in_test_harness =
  *running_status == '<' && Ustrcmp(running_status, "<<<testing>>>") == 0;

/* The C standard says that the equivalent of setlocale(LC_ALL, "C") is obeyed
at the start of a program; however, it seems that some environments do not
follow this. A "strange" locale can affect the formatting of timestamps, so we
make quite sure. */

setlocale(LC_ALL, "C");

/* Set up the default handler for timing using alarm(). */

os_non_restarting_signal(SIGALRM, sigalrm_handler);

/* Ensure we have a buffer for constructing log entries. Use malloc directly,
because store_malloc writes a log entry on failure. */

log_buffer = (uschar *)malloc(LOG_BUFFER_SIZE);
if (log_buffer == NULL)
  {
  fprintf(stderr, "exim: failed to get store for log buffer\n");
  exit(EXIT_FAILURE);
  }

/* Set log_stderr to stderr, provided that stderr exists. This gets reset to
NULL when the daemon is run and the file is closed. We have to use this
indirection, because some systems don't allow writing to the variable "stderr".
*/

if (fstat(fileno(stderr), &statbuf) >= 0) log_stderr = stderr;

/* Arrange for the PCRE regex library to use our store functions. Note that
the normal calls are actually macros that add additional arguments for
debugging purposes so we have to assign specially constructed functions here.
The default is to use store in the stacking pool, but this is overridden in the
regex_must_compile() function. */

pcre_malloc = function_store_get;
pcre_free = function_dummy_free;

/* Ensure there is a big buffer for temporary use in several places. It is put
in malloc store so that it can be freed for enlargement if necessary. */

big_buffer = store_malloc(big_buffer_size);

/* Set up the handler for the data request signal, and set the initial
descriptive text. */

set_process_info("initializing");
os_restarting_signal(SIGUSR1, usr1_handler);

/* SIGHUP is used to get the daemon to reconfigure. It gets set as appropriate
in the daemon code. For the rest of Exim's uses, we ignore it. */

signal(SIGHUP, SIG_IGN);

/* We don't want to die on pipe errors as the code is written to handle
the write error instead. */

signal(SIGPIPE, SIG_IGN);

/* Under some circumstance on some OS, Exim can get called with SIGCHLD
set to SIG_IGN. This causes subprocesses that complete before the parent
process waits for them not to hang around, so when Exim calls wait(), nothing
is there. The wait() code has been made robust against this, but let's ensure
that SIGCHLD is set to SIG_DFL, because it's tidier to wait and get a process
ending status. We use sigaction rather than plain signal() on those OS where
SA_NOCLDWAIT exists, because we want to be sure it is turned off. (There was a
problem on AIX with this.) */

#ifdef SA_NOCLDWAIT
  {
  struct sigaction act;
  act.sa_handler = SIG_DFL;
  sigemptyset(&(act.sa_mask));
  act.sa_flags = 0;
  sigaction(SIGCHLD, &act, NULL);
  }
#else
signal(SIGCHLD, SIG_DFL);
#endif

/* Save the arguments for use if we re-exec exim as a daemon after receiving
SIGHUP. */

sighup_argv = argv;

/* Set up the version number. Set up the leading 'E' for the external form of
message ids, set the pointer to the internal form, and initialize it to
indicate no message being processed. */

version_init();
message_id_option[0] = '-';
message_id_external = message_id_option + 1;
message_id_external[0] = 'E';
message_id = message_id_external + 1;
message_id[0] = 0;

/* Set the umask to zero so that any files Exim creates using open() are
created with the modes that it specifies. NOTE: Files created with fopen() have
a problem, which was not recognized till rather late (February 2006). With this
umask, such files will be world writeable. (They are all content scanning files
in the spool directory, which isn't world-accessible, so this is not a
disaster, but it's untidy.) I don't want to change this overall setting,
however, because it will interact badly with the open() calls. Instead, there's
now a function called modefopen() that fiddles with the umask while calling
fopen(). */

(void)umask(0);

/* Precompile the regular expression for matching a message id. Keep this in
step with the code that generates ids in the accept.c module. We need to do
this here, because the -M options check their arguments for syntactic validity
using mac_ismsgid, which uses this. */

regex_ismsgid =
  regex_must_compile(US"^(?:[^\\W_]{6}-){2}[^\\W_]{2}$", FALSE, TRUE);

/* Precompile the regular expression that is used for matching an SMTP error
code, possibly extended, at the start of an error message. Note that the
terminating whitespace character is included. */

regex_smtp_code =
  regex_must_compile(US"^\\d\\d\\d\\s(?:\\d\\.\\d\\d?\\d?\\.\\d\\d?\\d?\\s)?",
    FALSE, TRUE);

#ifdef WHITELIST_D_MACROS
/* Precompile the regular expression used to filter the content of macros
given to -D for permissibility. */

regex_whitelisted_macro =
  regex_must_compile(US"^[A-Za-z0-9_/.-]*$", FALSE, TRUE);
#endif


/* If the program is called as "mailq" treat it as equivalent to "exim -bp";
this seems to be a generally accepted convention, since one finds symbolic
links called "mailq" in standard OS configurations. */

if ((namelen == 5 && Ustrcmp(argv[0], "mailq") == 0) ||
    (namelen  > 5 && Ustrncmp(argv[0] + namelen - 6, "/mailq", 6) == 0))
  {
  list_queue = TRUE;
  receiving_message = FALSE;
  called_as = US"-mailq";
  }

/* If the program is called as "rmail" treat it as equivalent to
"exim -i -oee", thus allowing UUCP messages to be input using non-SMTP mode,
i.e. preventing a single dot on a line from terminating the message, and
returning with zero return code, even in cases of error (provided an error
message has been sent). */

if ((namelen == 5 && Ustrcmp(argv[0], "rmail") == 0) ||
    (namelen  > 5 && Ustrncmp(argv[0] + namelen - 6, "/rmail", 6) == 0))
  {
  dot_ends = FALSE;
  called_as = US"-rmail";
  errors_sender_rc = EXIT_SUCCESS;
  }

/* If the program is called as "rsmtp" treat it as equivalent to "exim -bS";
this is a smail convention. */

if ((namelen == 5 && Ustrcmp(argv[0], "rsmtp") == 0) ||
    (namelen  > …