/*
**
** wlmback.c    Willus.com backup program
**
** Originally written 9-23-99
**
** Version history
**
** v2.06        7-21-09
**             *Allows semicolons at beginning of lines in -xf/-if files
**              as comment chars.
**             *Compiled w/new wlm lib which does more robust directory
**              removal in Windows, but this works best if the user
**              has administrator rights.
**
** v2.05        6-18-09
**             *Compiled w/new wlm lib version which correctly parses
**              date from unzip 6.0 (official release) -v output.
**
** v2.04        6-16-09
**             *Fixed wlmback_forceful_remove() call in 
**              incremental_backup() function (wrong arg).
**             *Added wlmback_forceful_remove() to force removal of
**              .wlmback_old_files folder.  This is a kludge.  I'd prefer
**              to figure out why the recursive removal isn't working in
**              WIN32.
**             *Modified eprintf() to avoid segmentation fault in ubuntu.
**
** v2.03        11-7-08
**             *Changed formula for when to do a new full backup vs.
**              a "fullinc" backup.  The formula minimizes how much
**              backup data is written over the long term assuming
**              that the data size increases linearly over time:
**                  if (0.5*inc_size*days_since_last_full/days_per_cycle 
**                              >= last_full_size) then do a new full.
**              (The 0.5 wasn't there before.--do search on "suminc".)
**              See my backsim.c program.
**
** v2.02        7-23-08
**             *Added -mss option for minimum set size to avoid the
**              backup program creating a huge incremental backup of
**              "old" files when a volume isn't mounted.  This defaults to 1.
**
** v2.01        5-20-08
**             *Was aborting because it couldn't create the wlmback_old_files
**              folder, so I have it check if it exists first and try to
**              remove it first.
**
** v2.00        2-26-08, Major Rev
**             *Added restore capability!  See -rx and -rj options.
**              Only tested w/zip archives so far.
**             *Went to a "fullinc" system where instead of doing
**              a full backup every week or every designated number of
**              days, an new single incremental is done to the full
**              backup (the "fullinc" file).  This goes on until the
**              fullinc file gets big enough that it doesn't make sense
**              any more.  This should greatly reduce disk i/o and network
**              traffic involved with the backup files.  This new method
**              can be disabled with the -nfi flag.
**             *Instead of incrementals having an "old" and "new" dir,
**              they only have a ".wlmback_old_files" dir.  New files
**              are not put into a special folder.
**             *Compiled w/new wlm library that fixes daylight savings
**              time date issue with FAT volumes.
**             *Zip listings and extractions are case insensitive on Win32.
**             *unzip extracts w/-X flag for restore.
**
** v1.35        2-14-08
**             *Includes directories in the archive so that they will
**              extract themselves with correct time stamp and owner.
**              (zip and linux GNU-tar only for now.)
**             *Make compatible with zip 3.0g (Win32 change) which now
**              doesn't treat [ as a wildcard character.
**
** v1.34        11-14-07
**             *Include empty directories in the mix so that they don't
**              always get put in incremental backups.
**
** v1.33        11-12-07
**             *Added call to filelist_convert_simlink_sizes() so that
**              incremental zip backups don't always include all symbolic
**              links.
**
** v1.32        10-15-07
**             *Correctly archive file names with '[' in them on Linux(!).
**
** v1.31        10-12-07
**             *Added support for zip 3.0/unzip 6.0 (large files support)
**             *-max without args reports max archive size.
**             *Bumped ZIP64 limit to 8 EiB.
**             *Replaced GB and EB with GiB and EiB (per NIST).
**              (see http://physics.nist.gov/cuu/Units/binary.html)
**             *Correctly archives file names with '[' in them in zip archives.
**
** v1.30        2-6-07
**             *Uses revamped FILELIST structure from WLM library which
**              pools the file name string space to conserve memory.
**             *Uses some new ..._in_situ() functions to conserve memory
**              for large file lists.
**
** v1.29        11-7-06
**             *Added -mfs option for single file size limit.
**
** v1.28        7-5-06
**             *Increased max file name len from 256 to 512 (re-compiled
**              w/new wlm lib).
**
** v1.27        4-3-06
**             *Hopefully fixed more daylight savings time weirdness with
**              7-zip.
**             *Slightly changed some of the help text.
**
** v1.26        2-21-06
**             *Option to use lock file to prevent multiple instances from
**              running at the same time.
**             *For .tgz backups, writes the archive list to a separate
**              "cache" file since large .tgz files take a long time to
**              list.
**
** v1.25        1-23-06
**             *Avoid repeat calls to list the full backup archive.
**              See current_backup_get_list() function.
**             *Compiled with modified wfile_reslash() function so that
**              Linux file names with a backslash in them (\) are treated
**              correctly.
**             *Added -nkt flag.
**
** v1.24        1-12-06
**             *Added support for .tgz file archiving.  Haven't gotten
**              it to work under Windows.
**             *Added a windows icon to the build.
**
** v1.23        9-21-05
**             *Discovered bug on a PC where directories that
**              contained only excluded files were getting backed up.
**              This led to the "dirstoo=3" option for 
**              filelist_fill_from_disk().
**             *Turned back on linux recursive delete after extensive
**              testing.
**
** v1.22        8-9-05
**             *All backups always use an explicit file list now, rather
**              than using -x or -i flags with the zip or 7za commands.
**              This makes sure that backups are consistent across
**              different archiving programs and that wlmback controls
**              exactly which files are backed up.  This was prompted
**              by a problem where zip was recursing through symobolically
**              linked directories and ending up in an infinite loop.
**             *Added -y to zip option so that symbolic links are stored
**              as a link rather than the referenced file (Linux only).
**             *Stores symbolic links to dirs (but still doesn't recurse)
**              and empty dirs.
**
** v1.21        7-26-05
**             *Increased the zip max size to 256 TB on 64-bit Linux.
**             *Auto-detect 64-bit zip/unzip exes.
**             *rmdir recursive in Linux doesn't follow symbolic links
**              (disastrous!)
**
** v1.20        7-14-05
**             *Make compatible with 7za to surpass the 2 GiB barrier
**              and eliminate the need for multipart archives.
**             *Made the text output a little more colorful.
**             *Increased max includes/excludes from 64 to 1024.
**
** v1.16        6-11-04
**             *Trivial change--changed some of the diagnostic output
**              from net_copy().
**
** v1.15        6-9-04
**             *I added a "remove_old_files()" function which would
**              remove files older than the backup cycle, but I'm
**              very nervous about implementing it with no error
**              checking since a disk write problem could end up
**              potentially leaving the user with no backup files.
**              I have not implemented it yet, so there is no
**              version change.
**
** v1.15        12-3-03
**             *Added -xf and -if options.
**
** v1.14        10-28-03
**             *Added more details about how to use wlmback to the
**              wlmback -h usage, including some examples.
**
** v1.13        8-26-03
**             *Fixed a significant bug in Win32 version that prevented
**              full backups from being done (see wlmlib v2.69).
**
** v1.12        7-17-03
**             *Smarter about not searching excluded directories.
**             *Doesn't follow symbolically linked dirs in unix.
**             *Only archives unix files where S_ISREG returns TRUE.
**
** v1.11        1-15-03
**             *Added FTP capability to send backup files to another
**              server via FTP (Win32 only).
**
** v1.10        1-6-03
**             *Breaks 2 GiB barrier by creating multiple zip files if 
**              more than 2 GiB of content.  See -max command line option.
**             *In Win32, searches path for zip.exe and unzip.exe.
**
** v1.03        2-3-00
**              Made compatible with new wlmlib.  Now works only with
**              Zip v2.3 in WIN32.  Zip v2.2 stores dates differently.
**
** v1.02        11-3-99
**              Recompiled with wlm library v1.59 which now reports
**              WIN32 file dates the same whether in daylight savings
**              or not.
**
** v1.01        9-29-99
**              Change how "old" files are put in incremental backups.
**
** v1.00        9-23-99
**              wlmback is born.
**
**
*/