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Date:	Mon, 18 Oct 2010 13:38:28 -0700
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Subject:	makewhatis bug (man-1.6f-1)
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From:	Kevin Goodsell <kevin-dated-1295209163 DOT 43e24a AT omegacrash DOT net>
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makewhatis from man-1.6f-1 produces incorrectly formated output. Here's
an example comparing the badly-formatted results to correctly formatted
results:

$ man -k ssh
git []               (1)  - shell - Restricted login shell for GIT-only SSH access
ssh []               (1)  - add - adds RSA or DSA identities to the authentication agent
ssh []               (1)  - agent - authentication agent
ssh []               (1)  - copy-id - install your public key in a remote machine's authorized_keys
ssh []               (1)  - keygen - authentication key generation, management and conversion
ssh []               (1)  - keyscan - gather ssh public keys
ssh []               (1)  - OpenSSH SSH client (remote login program)
ssh []               (8)  - keysign - ssh helper program for host - based authentication
ssh []               (8)  - pkcs11-helper - ssh - agent helper program for PKCS#11 support
ssh_config []        (5)  - OpenSSH SSH client configuration files
sshd []              (8)  - OpenSSH SSH daemon
sshd_config []       (5)  - OpenSSH SSH daemon configuration file
XAllocClassHint []   (3)  - allocate class hints structure and set or read a window's WM_CLASS property
XClassHint []        (3)  - allocate class hints structure and set or read a window's WM_CLASS property
XGetClassHint []     (3)  - allocate class hints structure and set or read a window's WM_CLASS property
XSetClassHint []     (3)  - allocate class hints structure and set or read a window's WM_CLASS property

Using previous version:

$ man -k ssh
git-shell            (1)  - Restricted login shell for GIT-only SSH access
ssh                  (1)  - OpenSSH SSH client (remote login program)
ssh_config           (5)  - OpenSSH SSH client configuration files
ssh-add              (1)  - adds RSA or DSA identities to the authentication agent
ssh-agent            (1)  - authentication agent
ssh-copy-id          (1)  - install your public key in a remote machine's authorized_keys
sshd                 (8)  - OpenSSH SSH daemon
sshd_config          (5)  - OpenSSH SSH daemon configuration file
ssh-keygen           (1)  - authentication key generation, management and conversion
ssh-keyscan          (1)  - gather ssh public keys
ssh-keysign          (8)  - ssh helper program for host-based authentication
ssh-pkcs11-helper    (8)  - ssh-agent helper program for PKCS#11 support
XAllocClassHint      (3)  - allocate class hints structure and set or read a window's WM_CLASS property
XClassHint [XAllocClassHint] (3)  - allocate class hints structure and set or read a window's WM_CLASS property
XGetClassHint [XAllocClassHint] (3)  - allocate class hints structure and set or read a window's WM_CLASS property
XSetClassHint [XAllocClassHint] (3)  - allocate class hints structure and set or read a window's WM_CLASS property

The problem is in the whatis database itself, and is caused by a bug in
makewhatis in the upstream distribution. From the function do_one in the
section of awk code:

   use_zcat = match(filename,"\\.Z$") ||
              match(filename,"\\.z$") || match(filename,"\\.gz$");
   if (!use_zcat)
     use_bzcat = match(filename,"\\.bz2");
   if(!use_bzcat)
     use_lzcat = match(filename,"\\.lzma");
   if (use_zcat || use_bzcat || use_lzcat ) {
     filename_no_gz = substr(filename, 0, RSTART - 1);
   } else {
     filename_no_gz = filename;
   }

When filname ends in .z, .Z, or .gz, use_zcat gets set, and match() sets
the variable RSTART. The check for a .bz2 file is careful not to call
match() if the file was already determined to be .gz (etc.), but the
newer .lzma-checking code fails to check for all earlier possibilities,
and invokes match() again. This trashes RSTART, causing the later
substr() call to give an unexpected result. How exactly this produces
the weird output above is left as an exercise to the reader, but fixing
the second 'if' fixes the problem.

A simple patch follows. It doesn't attempt to address the underlying
problem (that the decompression handling needs to be generalized), it's
just a quick fix. Interestingly there are other patches floating around
that add support for .xz files and repeat the .lzma mistake, making the
bug even worse.

-Kevin

--- makewhatis	2010-10-07 13:47:42.578125000 -0700
+++ makewhatis.fixed	2010-10-09 10:06:44.234375000 -0700
@@ -268,7 +268,7 @@
  			 match(filename,"\\.z$") || match(filename,"\\.gz$");
  	      if (!use_zcat)
  		use_bzcat = match(filename,"\\.bz2");
-              if(!use_bzcat)
+              if(!use_zcat && !use_bzcat)
                  use_lzcat = match(filename,"\\.lzma");
                if (use_zcat || use_bzcat || use_lzcat ) {
  		filename_no_gz = substr(filename, 0, RSTART - 1);

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