# Copyright (c) 1983 Eric P. Allman
# Copyright (c) 1988 The Regents of the University of California.
# %sccs.include.redist.sh%
# @(#)READ_ME 8.19 (Berkeley) %G%
This directory contains the source files for sendmail.
For detailed instructions, please read the document ../doc/op.me:
eqn ../doc/op.me | pic | ditroff -me
The Makefile is for the new (4.4BSD) Berkeley make, available from
ftp.uu.net in the directory /systems/unix/bsd-sources/usr.bin/make.
It has assumptions about the 4.4 file system layout built in. There
is also a Makefile.dist which is much less clever, but works on the
old traditional make. You can use this using:
There are a bunch of other Makefiles for other systems -- these are
the ones that I use, they have "Berkeley quirks" in them, and I don't
guarantee that they will work unmodified in your environment. However,
they are all designed for the old make and can be used to help you get
started. They have names like "Makefile.HPUX". Many of them include
-I/usr/sww/include/db and -L/usr/sww/lib -- this is Berkeley's
location for the new database libraries, described below.
There is also a shell script (makesendmail) that tries to be clever
about using object subdirectories. It's pretty straightforward, and
may help if you share a source tree among different architectures.
There are several database formats that can be used for the alias files
and for general maps. When used for alias files they interact in an
attempt to be back compatible.
The three options are NEWDB (the new Berkeley DB package), NDBM (the
older DBM implementation -- the very old V7 implementation is no
longer supported), and NIS (Network Information Services). Used alone
these just include the support they indicate.
If NEWDB and NDBM are defined (but not NIS), then sendmail will read
NDBM format alias files, but the next time a newaliases is run the
format will be converted to NEWDB; that format will be used forever
more. This is intended as a transition feature. [Note however that
the NEWDB library also catches and maps NDBM calls; you will have to
back out this feature to get this to work. See ``Quirks'' section
If all three are defined, sendmail operates as described above, and also
looks for the file /var/yp/Makefile. If it exists, newaliases will
build BOTH the NEWDB and NDBM format alias files. However, it will
only use the NEWDB file; the NDBM format file is used only by the
If NDBM and NIS are defined (regardless of the definition of NEWDB
or the existance of /var/yp/Makefile), sendmail adds the special
tokens "YP_LAST_MODIFIED" and "YP_MASTER_NAME", both of which are
required if the NDBM file is to be used as an NIS map.
All of -DNEWDB, -DNDBM, and -DNIS are normally defined in the DBMDEF
Whereever possible, I try to make sendmail pull in the correct
compilation options needed to compile on various environments based on
automatically defined symbols. Some machines don't seem to have useful
symbols availble, requiring the following compilation flags in the
SOLARIS Define this if you are running Solaris 2.0 or higher.
NeXT Define this if you are on a NeXT box. (This one may
be pre-defined for you.) There are other hacks you
have to make -- see below.
_AIX3 Define this if you are IBM AIX 3.x.
RISCOS Define this if you are running RISC/os from MIPS.
If you are a system that sendmail has already been ported to, you
probably won't have to touch these. But if you are porting, you may
have to tweak the following compilation flags in conf.h in order to
get it to compile and link properly:
SYSTEM5 Adjust for System V.
SYS5SIGNALS Use System V signal semantics -- the signal handler
is automatically dropped when the signal is caught.
If this is not set, use POSIX/BSD semantics, where the
signal handler stays in force until an exec or an
explicit delete. Implied by SYSTEM5.
HASFLOCK Set this if you prefer to use the flock(2) system call
rather than using fcntl-based locking. Fcntl locking
has some semantic gotchas, but many vendor systems
also interface it to lockd(8) to do NFS-style locking.
For this reason, this should not be set unless you
don't have an alternative.
HASUNAME Set if you have the "uname" system call. Implied by
HASUNSETENV Define this if your system library has the "unsetenv"
HASSTATFS Define this if you have the statfs(2) system call. It's
not a disaster to get this wrong -- but you do lose the
HASUSTAT Define this if you have the ustat(2) system call. It's
not a disaster to get this wrong -- but you do lose the
HASSETSID Define this if you have the setsid(2) system call. This
is implied if your system appears to be POSIX compliant.
HASINITGROUPS Define this if you have the initgroups(3) routine.
HASSETVBUF Define this if you have the setvbuf(3) library call.
If you don't, setlinebuf will be used instead. This
defaults on if your compiler defines __STDC__.
HASSETREUID Define this if you have setreuid(2) ***AND*** root can
use setreuid to change to an arbitrary user. This second
condition is not satisfied on AIX 3.x. You may find that
your system has setresuid(2), (for example, on HP-UX) in
which case you will also have to #define setreuid(r, e)
to be the appropriate call. Some systems (such as Solaris)
have a compatibility routine that doesn't work properly.
The important thing is that you have a call that will set
the effective uid independently of the real or saved uid.
Setting this improves the security somewhat, since
sendmail doesn't have to read .forward and :include: files
GIDSET_T The type of entries in a gidset passed as the second
argument to getgroups(2). Historically this has been an
int, so this is the default, but some systems (such as
IRIX) pass it as a gid_t, which is an unsigned short.
This will make a difference, so it is important to get
this right! However, it is only an issue if you have
SLEEP_T The type returned by the system sleep() function.
Defaults to "unsigned int". Don't worry about this
if you don't have compilation problems.
ARBPTR_T The type of an arbitrary pointer -- defaults to "void *".
If you are an very old compiler you may need to define
LA_TYPE The type of load average your kernel supports. These
can be LA_SUBR (4) if you have the getloadavg(3) routine,
LA_FLOAT (3) if you read kmem and interpret the value
as a floating point number, LA_INT (2) to interpret as
an integer. These last two have several other parameters
that they try to divine: the name of your kernel, the name
of the variable in the kernel to examine, the number of
bits of precision in a fixed point load average, and so
forth. In desparation, use LA_ZERO -- it always returns
the load average as "zero" (and does so on all architectures).
The actual code is in conf.c -- it can be tweaked if you
If set, assumes that some header file defines sys_errlist.
This may be needed if you get type conflicts on this
variable -- otherwise don't worry about it.
+-----------------------+
| COMPILE-TIME FEATURES |
+-----------------------+
There are a bunch of features that you can decide to compile in, such
as selecting various database packages and special protocol support.
Several are assumed based on other compilation flags -- if you want to
"un-assume" something, you probably need to edit conf.h. Compilation
flags that add support for special features include:
NDBM Include support for "new" DBM library for aliases and maps.
Normally defined in the Makefile.
NEWDB Include support for Berkeley "db" package (hash & btree)
for aliases and maps. Normally defined in the Makefile.
NIS Define this to get NIS (YP) support for aliases and maps.
Normally defined in the Makefile.
USERDB Include support for the User Information Database. Implied
IDENTPROTO Define this to get IDENT (RFC 1413) protocol support.
This is assumed unless you are running on Ultrix or
HP-UX, both of which have a problem in the UDP
MIME Include support for MIME-encapsulated error messages.
LOG Set this to get syslog(3) support. Defined by default
in conf.h. You want this if at all possible.
NETINET Set this to get TCP/IP support. Defined by default
in conf.h. You probably want this.
NETISO Define this to get ISO networking support.
SMTP Define this to get the SMTP code. Implied by NETINET
NAMED_BIND Define this to get DNS (name daemon) support, including
MX support. The specs you must use this if you run
SMTP. Defined by default in conf.h.
QUEUE Define this to get queueing code. Implied by NETINET
or NETISO; required by SMTP. This gives you other good
stuff -- it should be on.
DAEMON Define this to get general network support. Implied by
NETINET or NETISO. Defined by default in conf.h. You
almost certainly want it on.
MATCHGECOS Permit fuzzy matching of user names against the full
name (GECOS) field in the /etc/passwd file. This should
probably be on, since you can disable it from the config
file if you want to. Defined by default in conf.h.
SETPROCTITLE Try to set the string printed by "ps" to something
informative about what sendmail is doing. Defined by
+-------------------------------------+
| OPERATING SYSTEM AND COMPILE QUIRKS |
+-------------------------------------+
You may have to use -lresolv on SunOS.
in /etc/nsswitch.conf and /etc/hosts has to have the fully
qualified host name. I think "files" has to be before "dns"
in /etc/nsswitch.conf during bootup.
If you are compiling on OSF/1 (DEC Alpha), you must use -lmld.
If you are compiling on NeXT, you will have to create an empty
file "unistd.h" and create a file "dirent.h" containing:
(The Makefile.NeXT should try to do both of these for you.)
Apparently, there is a bug in getservbyname on Nextstep 3.0
that causes it to fail under some circumstances with the
message "SYSERR: service "smtp" unknown" logged. You should
be able to work around this by including the line:
I have reports that the "m4" from BSDI won't handle the config
files properly. I haven't had a chance to test this myself.
If you are running a "virgin" version of 4.3BSD, you'll have
a very old resolver and be missing some header files. The
header files are simple -- create empty versions and everything
will work fine. For the resolver you should really port a new
version (4.8.3 or later) of the resolver; 4.9 is available on
gatekeeper.DEC.COM in pub/BSD/bind/4.9. If you are really
determined to continue to use your old, buggy version (or as
a shortcut to get sendmail working -- I'm sure you have the
best intentions to port a modern version of BIND), you can
copy ../contrib/oldbind.compat.c into src and add
oldbind.compat.o to OBJADD in the Makefile.
If you use both -DNDBM and -DNEWDB, you must delete the module
ndbm.o from libdb.a and delete the file "ndbm.h" from the files
that get installed (that is, use the OLD ndbm.h, not the new
ndbm.h). This compatibility module maps ndbm calls into DB
calls, and breaks things rather badly.
+-----------------------------+
| DESCRIPTION OF SOURCE FILES |
+-----------------------------+
The following list describes the files in this directory:
Makefile The makefile used here; this version only works with
Makefile.dist A trimmed down version of the makefile that works with
TRACEFLAGS My own personal list of the trace flags -- not guaranteed
to be particularly up to date.
alias.c Does name aliasing in all forms.
arpadate.c A subroutine which creates ARPANET standard dates.
clock.c Routines to implement real-time oriented functions
in sendmail -- e.g., timeouts.
collect.c The routine that actually reads the mail into a temp
file. It also does a certain amount of parsing of
conf.c The configuration file. This contains information
that is presumed to be quite static and non-
controversial, or code compiled in for efficiency
reasons. Most of the configuration is in sendmail.cf.
conf.h Configuration that must be known everywhere.
convtime.c A routine to sanely process times.
daemon.c Routines to implement daemon mode. This version is
specifically for Berkeley 4.1 IPC.
deliver.c Routines to deliver mail.
domain.c Routines that interface with DNS (the Domain Name
err.c Routines to print error messages.
envelope.c Routines to manipulate the envelope structure.
headers.c Routines to process message headers.
macro.c The macro expander. This is used internally to
insert information from the configuration file.
main.c The main routine to sendmail. This file also
contains some miscellaneous routines.
map.c Support for database maps.
mci.c Routines that handle mail connection information caching.
parseaddr.c The routines which do address parsing.
queue.c Routines to implement message queueing.
readcf.c The routine that reads the configuration file and
translates it to internal form.
recipient.c Routines that manipulate the recipient list.
savemail.c Routines which save the letter on processing errors.
sendmail.h Main header file for sendmail.
srvrsmtp.c Routines to implement server SMTP.
stab.c Routines to manage the symbol table.
stats.c Routines to collect and post the statistics.
sysexits.c List of error messages associated with error codes
trace.c The trace package. These routines allow setting and
testing of trace flags with a high granularity.
udb.c The user database interface module.
usersmtp.c Routines to implement user SMTP.
util.c Some general purpose routines used by sendmail.
version.c The version number and information about this
version of sendmail. Theoretically, this gets
modified on every change.
(Version 8.19, last update %G% 11:22:15)
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