|
|
2.2 Obtain the SourceThe latest release of sendmail is available via: http://www.sendmail.org/current-release.html When you download the source you must select one file from many that are listed. In addition to selecting the version you want, you must choose between two forms of compressed tar(1) distributions. Those that end in .Z are compressed with Unix compress(1); those that end in .gz are compressed with GNU gzip(1). The latter is the preferred form because the file is smaller and therefore quicker to transfer. In addition to the two forms of distribution, each release has a PGP signature file associated with it.[2] This is a signature of the uncompressed file, so you need to uncompress the tar(1) file before verifying it.
To verify V8.5 or earlier distributions, get Eric Allman's public key by sending email to pgp-public-keys@keys.pgp.net with the following subject line: Subject: MGET Allman Eric Allman's public key will be mailed back to you a few minutes later. Save that returned email to a file—for example, /tmp/eric.asc—and add that key to your public "keyring" with the command: % pgp -ka /tmp/eric.asc For V8.6 and above, you download a special signing key from www.sendmail.org, instead of Eric's key. The fingerprint for the signing key is: CA AE F2 94 3B 1D 41 3C 94 7B 72 5F AE 0B 6A 11 The fingerprint for Eric's key is: C0 28 E6 7B 13 5B 29 02 6F 7E 43 3A 48 4F 45 29 Once you have the appropriate key, execute the following command for the uncompressed source file: pgp signature-file If the uncompressed tar file is good, pgp(1) will report that the signature is valid. A few things can go wrong here, causing the verification to fail:
If your copy of the sendmail distribution fails to verify, don't use it! 2.2.1 What's Where in the SourceV8.12 sendmail unpacks by creating a directory, then unpacking into that directory. The directory name is the same as the compressed filename but with a dash instead of the first dot: % gzcat sendmail.8.12.7.tar.gz | tar xvf -
x sendmail-8.12.7/FAQ, 321 bytes, 1 tape blocks
x sendmail-8.12.7/INSTALL, 1396 bytes, 3 tape blocks
x sendmail-8.12.7/KNOWNBUGS, 8770 bytes, 18 tape blocks
... and so on
Inside the newly created directory you will find the full sendmail distribution: % cd sendmail-8.12.7 % ls Build README include makemap FAQ RELEASE_NOTES libmilter praliases INSTALL cf libsm rmail KNOWNBUGS contrib libsmdb sendmail LICENSE devtools libsmutil smrsh Makefile doc mail.local test PGPKEYS editmap mailstats vacation The README and RELEASE_NOTES files provide the most up-to-date information about changes, new features, and bug fixes. Read the documents in the doc directory. Also note that the README files in all the subdirectories contain important comments as well. The files and directories in the source directory are listed in Table 2-1, and are described in detail in the sections that follow.
2.2.1.1 The top-level Build scriptThe top-level Build script can be used to do a global build across all programs. For example, you can do this to build all the programs: % ./Build All the commands you can use with the master Build (Section 5.1) are available to this Build. 2.2.1.2 The contrib directoryThe contrib directory contains user-contributed and unsupported code. Among its contents are perl(1) scripts, shell scripts, C-language source code, and patches. The README file in this directory explains some of the policy surrounding the programs. For more complete information you will need to dig through the source files yourself. If you have software that you would like to see included in this directory, email a description of that program to sendmail@sendmail.org. 2.2.1.3 The devtools directoryThe devtools directory contains all the scripts and m4(1) source used to build sendmail and its libraries and companion programs. The README file there briefly describes the m4 macros used to configure your build process. We describe the current macros in Section 2.4. You should consult this file whenever a new release is issued because it will always have the most up-to-date information. The devtools/Site directory is the default location for your m4 build configuration files. The README in that directory describes the strategy used to locate a build configuration file. Note that the -f command-line switch (-f) for the Build command can override use of that directory. Also note that the -Q command-line switch (-Q) for the Build command modifies the way an m4 file is found. 2.2.1.4 The doc directoryThe doc directory contains only one subdirectory, op. The doc/op directory contains the sendmail "INSTALLATION AND OPERATION GUIDE." That guide is supplied in troff(1) source (op.me), and as a ready-to-print PostScript document (op.ps). This is the main document distributed with sendmail that describes that program. It is succinct, and always a good place to start for a quick but detailed overview. 2.2.1.5 The include directoryThe include directory contains four subdirectories. The include/libsmdb directory contains files that support the use of the libsmdb library of common database routines. The include/sendmail directory contains files useful for sendmail and for programs that share the sendmail definitions and declarations (for example, the mailstats program). The include/libmilter directory contains files that support use of the libmilter library of routines. The include/sm directory contains files that support use of the libsm library of routines. 2.2.1.6 The INSTALL fileThe INSTALL file contains a brief list of steps for compiling and installing sendmail. 2.2.1.7 The KNOWNBUGS fileThe KNOWNBUGS file contains a (not always up-to-date) list of the most difficult bugs to fix in the sendmail program. Presence of this file ought not suggest that sendmail is distributed with bugs. Rather, it should assure you that reported bugs are admitted to and dealt with. If you encounter behavior with sendmail that appears to be a bug in sendmail and not in another program, document that bug carefully so that it can be repeated, and send your description of it to sendmail-bugs@sendmail.org. If you encounter a security problem with sendmail, use the fingerprint and public key stored in the PGPKEYS file to encrypt a message and send that message to sendmail-security@sendmail.org. Always try to avoid sending security-related email in clear text. 2.2.1.8 The libmilter directoryThe sendmail folks have defined a mail filter API called milter. Using this API, third-party programmers (you, for example) can design programs to access mail messages as they are being processed by sendmail. Such real-time access allows email message content to be filtered and possibly rejected based on content—a potentially powerful anti-spam tool. The README file in this directory describes the steps needed to design, compile, and run such a filter. But beware. The use of this API and creation of a filter program require the use of POSIX threads. If your OS lacks POSIX thread support, you will not be able to use this API. For systems that support POSIX threads, we illustrate the creation and use of a mail filter program in Section 7.6. 2.2.1.9 The libsm directoryTo support many of the new features in sendmail, and to pave the way for more sophisticated versions in the future, the designers of sendmail decided to create a replacement for many of the routines in the standard C library. A quick glance at that directory will reveal replacements, for example, of fput(3) and ungetc(3). A library of these routines is built and used by sendmail automatically when you build that program. You need do nothing special here. In the rare event that you need to port sendmail to an entirely new operating system, you will need to study the file README in that directory, and examine (and perhaps tweak) some of the various C source files there. 2.2.1.10 The libsmdb directoryThe libsmdb directory contains source for a library that supports opening, reading, writing, searching, and closing database files. The types of database files supported are Berkeley db (versions 1, 2, and 3), btree and hash, and ndbm. This library is used by makemap, praliases, editmap, and vacation. 2.2.1.11 The libsmutil directoryThe libsmutil directory contains source for a library of routines that are useful to sendmail and its companion programs. Among the routines are support for debugging with -d (Section 16.1), the checking of safe files and directories (-d44.4), and other useful tasks. 2.2.1.12 The LICENSE fileThe LICENSE file contains the legal jargon surrounding how, when, and why you can use the source and the programs produced by that source. It also includes instructions on how to get updated license information. 2.2.1.13 The Makefile fileThe top-level Makefile file can be used to globally compile all the programs in the distribution. It uses two environment variables: CONFIG and FLAGS. These can either be put into make's environment as part of its command line, or put into your shell's environment. The first technique is used when you wish to condition one of these variables just once or so. The second is useful when a variable setting is needed over and over during a prolonged development session. The first technique looks like this: % make CONFIG="-Q Server" FLAGS="-c" Here, the CONFIG variable is used to set the location for your m4 build file, and the FLAGS variable is used to pass any other command-line switches you need to the Build program. The second technique begins by conditioning your shell's environment variables: setenv CONFIG "-Q Server" You will see the result of declaring these two environment variables when you run the make(1) program, this time without having to specify those two variables in the command line: % make all See Section 5.1 for an overview of how Build works, and what the -c and -Q switches do. 2.2.1.14 The PGPKEYS fileThe PGPKEYS file contains the keys used to validate the authenticity of the sendmail distribution. To use them, however, you first need to unpack the distribution, then run pgp on the uncompress tar file. This might give you the impression of safety, but be aware that a fake distribution can contain fake keys in a fake PGPKEYS file, and the fake PGPKEYS file will verify the fake distribution. See Section 2.2 for a description of the better way to validate your sendmail distribution. 2.2.1.15 The README fileThe README file's name should encourage you to do just what it says. Read that file whenever you download a fresh distribution. It contains lots of useful and up-to-date information. 2.2.1.16 The RELEASE_NOTES fileThe RELEASE_NOTES file contains a comprehensive and cumulative history of the sendmail program. It is organized by release date, with the most recent first, and earlier releases following in order, by age. Each section shows changes to the code, changes to the configuration files, and changes that affect compiling. This file is a must-read because it details in one place all the changes that are included in the current and prior releases. 2.2.1.17 The test directoryThe test directory contains C-language programs that help the development team at sendmail.com solve problems concerning the porting of sendmail to other architectures. They are of interest only if you intend to port sendmail to a currently unsupported platform. Each .c file is somewhat self-documenting. |
|
|
for pgp version 2.x
% pgpk -a /tmp/eric.asc