view tests/test-hgweb-raw.t @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

#require serve

Test raw style of hgweb

  $ hg init test
  $ cd test
  $ mkdir sub
  $ cat >'sub/some text%.txt' <<ENDSOME
  > This is just some random text
  > that will go inside the file and take a few lines.
  > It is very boring to read, but computers don't
  > care about things like that.
  > ENDSOME
  $ hg add 'sub/some text%.txt'
  $ hg commit -d "1 0" -m "Just some text"

  $ hg serve -p $HGPORT -A access.log -E error.log -d --pid-file=hg.pid

  $ cat hg.pid >> $DAEMON_PIDS
  $ (get-with-headers.py localhost:$HGPORT 'raw-file/bf0ff59095c9/sub/some%20text%25.txt' content-type content-length content-disposition) >getoutput.txt

  $ killdaemons.py hg.pid

  $ cat getoutput.txt
  200 Script output follows
  content-type: application/binary
  content-length: 157
  content-disposition: inline; filename="some text%.txt"
  
  This is just some random text
  that will go inside the file and take a few lines.
  It is very boring to read, but computers don't
  care about things like that.
  $ cat access.log error.log
  $LOCALIP - - [$LOGDATE$] "GET /raw-file/bf0ff59095c9/sub/some%20text%25.txt HTTP/1.1" 200 - (glob)

  $ rm access.log error.log
  $ hg serve -p $HGPORT -A access.log -E error.log -d --pid-file=hg.pid \
  > --config web.guessmime=True

  $ cat hg.pid >> $DAEMON_PIDS
  $ (get-with-headers.py localhost:$HGPORT 'raw-file/bf0ff59095c9/sub/some%20text%25.txt' content-type content-length content-disposition) >getoutput.txt
  $ killdaemons.py hg.pid

  $ cat getoutput.txt
  200 Script output follows
  content-type: text/plain; charset="ascii"
  content-length: 157
  content-disposition: inline; filename="some text%.txt"
  
  This is just some random text
  that will go inside the file and take a few lines.
  It is very boring to read, but computers don't
  care about things like that.
  $ cat access.log error.log
  $LOCALIP - - [$LOGDATE$] "GET /raw-file/bf0ff59095c9/sub/some%20text%25.txt HTTP/1.1" 200 - (glob)

  >>> with open('sub/binary.bin', 'wb') as fp:
  ...     fp.write(b'Binary\0file') and None

  $ hg ci -Aqm "add binary file" sub/
  $ hg serve -p $HGPORT -A access.log -E error.log -d --pid-file=hg.pid \
  > --config web.guessmime=True
  $ cat hg.pid >> $DAEMON_PIDS
  $ (get-with-headers.py localhost:$HGPORT 'annotate/tip/sub/binary.bin' content-type content-length content-disposition) >getoutput.txt
  $ cat getoutput.txt
  200 Script output follows
  content-type: text/html; charset=ascii
  
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
  <head>
  <link rel="icon" href="/static/hgicon.png" type="image/png" />
  <meta name="robots" content="index, nofollow" />
  <link rel="stylesheet" href="/static/style-paper.css" type="text/css" />
  <script type="text/javascript" src="/static/mercurial.js"></script>
  
  <title>$TESTTMP/test: sub/binary.bin annotate</title> (glob)
  </head>
  <body>
  
  <div class="container">
  <div class="menu">
  <div class="logo">
  <a href="https://mercurial-scm.org/">
  <img src="/static/hglogo.png" alt="mercurial" /></a>
  </div>
  <ul>
  <li><a href="/shortlog/tip">log</a></li>
  <li><a href="/graph/tip">graph</a></li>
  <li><a href="/tags">tags</a></li>
  <li><a href="/bookmarks">bookmarks</a></li>
  <li><a href="/branches">branches</a></li>
  </ul>
  
  <ul>
  <li><a href="/rev/tip">changeset</a></li>
  <li><a href="/file/tip/sub/">browse</a></li>
  </ul>
  <ul>
  <li><a href="/file/tip/sub/binary.bin">file</a></li>
  <li><a href="/file/tip/sub/binary.bin">latest</a></li>
  <li><a href="/diff/tip/sub/binary.bin">diff</a></li>
  <li><a href="/comparison/tip/sub/binary.bin">comparison</a></li>
  <li class="active">annotate</li>
  <li><a href="/log/tip/sub/binary.bin">file log</a></li>
  <li><a href="/raw-file/tip/sub/binary.bin">raw</a></li>
  </ul>
  <ul>
  <li><a href="/help">help</a></li>
  </ul>
  </div>
  
  <div class="main">
  <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
  <h3>
   annotate sub/binary.bin @ 1:<a href="/rev/7dc31308464a">7dc31308464a</a>
   <span class="phase">draft</span> <span class="branchhead">default</span> <span class="tag">tip</span> 
  </h3>
  
  
  <form class="search" action="/log">
  
  <p><input name="rev" id="search1" type="text" size="30" value="" /></p>
  <div id="hint">Find changesets by keywords (author, files, the commit message), revision
  number or hash, or <a href="/help/revsets">revset expression</a>.</div>
  </form>
  
  <div class="description">add binary file</div>
  
  <table id="changesetEntry">
  <tr>
   <th class="author">author</th>
   <td class="author">&#116;&#101;&#115;&#116;</td>
  </tr>
  <tr>
   <th class="date">date</th>
   <td class="date age">Thu, 01 Jan 1970 00:00:00 +0000</td>
  </tr>
  <tr>
   <th class="author">parents</th>
   <td class="author"></td>
  </tr>
  <tr>
   <th class="author">children</th>
   <td class="author"></td>
  </tr>
  </table>
  
  
  <form id="diffopts-form"
  data-ignorews="0"
  data-ignorewsamount="0"
  data-ignorewseol="0"
  data-ignoreblanklines="0">
  <span>Ignore whitespace changes - </span>
  <span>Everywhere:</span>
  <input id="ignorews-checkbox" type="checkbox" />
  <span>Within whitespace:</span>
  <input id="ignorewsamount-checkbox" type="checkbox" />
  <span>At end of lines:</span>
  <input id="ignorewseol-checkbox" type="checkbox" />
  </form>
  
  <script type="text/javascript">
      renderDiffOptsForm();
  </script>
  
  <div class="overflow">
  <table class="bigtable">
  <thead>
  <tr>
   <th class="annotate">rev</th>
   <th class="line">&nbsp;&nbsp;line source</th>
  </tr>
  </thead>
  <tbody class="stripes2 sourcelines"
         data-logurl="/log/tip/sub/binary.bin"
         data-selectabletag="TR"
         data-ishead="1">
    
  <tr id="l1" class="thisrev">
  <td class="annotate parity0">
  <a href="/annotate/7dc31308464a/sub/binary.bin#l1">
  1
  </a>
  <div class="annotate-info">
  <div>
  <a href="/annotate/7dc31308464a/sub/binary.bin#l1">
  7dc31308464a</a>
  add binary file
  </div>
  <div><em>&#116;&#101;&#115;&#116;</em></div>
  <div>parents: </div>
  <a href="/diff/7dc31308464a/sub/binary.bin">diff</a>
  <a href="/rev/7dc31308464a">changeset</a>
  </div>
  </td>
  <td class="source followlines-btn-parent"><a href="#l1">     1</a> (binary:application/octet-stream)</td>
  </tr>
  </tbody>
  </table>
  </div>
  </div>
  </div>
  
  <script type="text/javascript" src="/static/followlines.js"></script>
  
  
  
  </body>
  </html>
  
  $ (get-with-headers.py localhost:$HGPORT 'comparison/tip/sub/binary.bin' content-type content-length content-disposition) >getoutput.txt
  $ (get-with-headers.py localhost:$HGPORT 'file/tip/sub/binary.bin' content-type content-length content-disposition) >getoutput.txt
  $ (get-with-headers.py localhost:$HGPORT 'static/hgicon.png' content-type content-length content-disposition) >getoutput.txt
  $ killdaemons.py hg.pid
  $ cat access.log error.log
  $LOCALIP - - [$LOGDATE$] "GET /raw-file/bf0ff59095c9/sub/some%20text%25.txt HTTP/1.1" 200 - (glob)
  $LOCALIP - - [$LOGDATE$] "GET /annotate/tip/sub/binary.bin HTTP/1.1" 200 - (glob)
  $LOCALIP - - [$LOGDATE$] "GET /comparison/tip/sub/binary.bin HTTP/1.1" 200 - (glob)
  $LOCALIP - - [$LOGDATE$] "GET /file/tip/sub/binary.bin HTTP/1.1" 200 - (glob)
  $LOCALIP - - [$LOGDATE$] "GET /static/hgicon.png HTTP/1.1" 200 - (glob)

  $ cd ..