Add support for package submission

1 files changed, 715 insertions, 0 deletions

diff --git a/mod/mod-submit.cxx b/mod/mod-submit.cxx
new file mode 100644
index 0000000..ff5fa9d
--- /dev/null
+++ b/mod/mod-submit.cxx
@@ -0,0 +1,715 @@
+// file      : mod/mod-submit.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <mod/mod-submit.hxx>
+
+#include <cstdlib> // strtoul()
+#include <istream>
+
+#include <libbutl/sha256.mxx>
+#include <libbutl/process.mxx>
+#include <libbutl/sendmail.mxx>
+#include <libbutl/fdstream.mxx>
+#include <libbutl/timestamp.mxx>
+#include <libbutl/filesystem.mxx>
+#include <libbutl/process-io.mxx>          // operator<<(ostream, process_args)
+#include <libbutl/manifest-parser.mxx>
+#include <libbutl/manifest-serializer.mxx>
+
+#include <web/xhtml.hxx>
+#include <web/module.hxx>
+
+#include <mod/page.hxx>
+#include <mod/options.hxx>
+
+using namespace std;
+using namespace butl;
+using namespace web;
+using namespace brep::cli;
+
+brep::submit::
+submit (const submit& r)
+    : handler (r),
+      options_ (r.initialized_ ? r.options_ : nullptr),
+      form_ (r.initialized_ || r.form_ == nullptr
+             ? r.form_
+             : make_shared<xhtml::fragment> (*r.form_))
+{
+}
+
+void brep::submit::
+init (scanner& s)
+{
+  HANDLER_DIAG;
+
+  options_ = make_shared<options::submit> (
+    s, unknown_mode::fail, unknown_mode::fail);
+
+  // Verify that the submission handling is setup properly, if configured.
+  //
+  if (options_->submit_data_specified ())
+  {
+    // Verify that directories satisfy the requirements.
+    //
+    auto verify = [&fail] (const dir_path& d, const char* what)
+    {
+      if (d.relative ())
+        fail << what << " directory path must be absolute";
+
+      if (!dir_exists (d))
+        fail << what << " directory '" << d << "' does not exist";
+    };
+
+    verify (options_->submit_data (), "submit-data");
+    verify (options_->submit_temp (), "submit-temp");
+
+    // Parse XHTML5 form file, if configured.
+    //
+    if (options_->submit_form_specified ())
+    {
+      const path& submit_form (options_->submit_form ());
+
+      if (submit_form.relative ())
+        fail << "submit-form path must be absolute";
+
+      try
+      {
+        ifdstream is (submit_form);
+
+        form_ = make_shared<xhtml::fragment> (is.read_text (),
+                                              submit_form.string ());
+      }
+      catch (const xml::parsing& e)
+      {
+        fail << "unable to parse submit-form file: " << e;
+      }
+      catch (const io_error& e)
+      {
+        fail << "unable to read submit-form file '" << submit_form << "': "
+             << e;
+      }
+    }
+
+    if (options_->submit_handler_specified () &&
+        options_->submit_handler ().relative ())
+      fail << "submit-handler path must be absolute";
+  }
+
+  if (options_->root ().empty ())
+    options_->root (dir_path ("/"));
+}
+
+bool brep::submit::
+handle (request& rq, response& rs)
+{
+  using namespace xhtml;
+
+  using parser        = manifest_parser;
+  using parsing       = manifest_parsing;
+  using serializer    = manifest_serializer;
+  using serialization = manifest_serialization;
+
+  HANDLER_DIAG;
+
+  const dir_path& root (options_->root ());
+
+  // We will respond with the manifest to the submission protocol violations
+  // and with a plain text message on the internal errors. In the latter case
+  // we will always respond with the same neutral message for security reason,
+  // logging the error details. Note that descriptions of exceptions caught by
+  // the web server are returned to the client (see web/module.hxx for
+  // details), and we want to avoid this when there is a danger of exposing
+  // sensitive data.
+  //
+  // Also we will pass through exceptions thrown by the underlying API, unless
+  // we need to handle them or add details for the description, in which case
+  // we will fallback to one of the above mentioned response methods.
+  //
+  // Note that both respond_manifest() and respond_error() are normally called
+  // right before the end of the request handling. They both always return
+  // true to allow bailing out with a single line, for example:
+  //
+  // return respond_error (); // Request is handled with an error.
+  //
+  auto respond_manifest = [&rs] (status_code status,
+                                 const string& message,
+                                 const char* ref = nullptr) -> bool
+  {
+    serializer s (rs.content (status, "text/manifest;charset=utf-8"),
+                  "response");
+
+    s.next ("", "1"); // Start of manifest.
+    s.next ("status", to_string (status));
+    s.next ("message", message);
+
+    if (ref != nullptr)
+      s.next ("reference", ref);
+
+    s.next ("", ""); // End of manifest.
+    return true;
+  };
+
+  auto respond_error = [&rs] (status_code status = 500) -> bool
+  {
+    rs.content (status, "text/plain;charset=utf-8") << "unable to handle "
+      << "submission" << endl;
+    return true;
+  };
+
+  // Check if the package submission functionality is enabled.
+  //
+  // Note that this is not a submission protocol violation but it feels right
+  // to respond with the manifest, to help the client a bit.
+  //
+  if (!options_->submit_data_specified ())
+    return respond_manifest (404, "submission disabled");
+
+  // Parse the request form data and verifying the submission size limit.
+  //
+  // Note that if it is exceeded, then there are parameters and this is the
+  // submission rather than the form request, and so we respond with the
+  // manifest.
+  //
+  try
+  {
+    rq.parameters (options_->submit_max_size ());
+  }
+  catch (const invalid_request& e)
+  {
+    if (e.status == 413) // Payload too large?
+      return respond_manifest (e.status, "submission size exceeds limit");
+
+    throw;
+  }
+
+  // The request parameters are now parsed and the limit doesn't really matter.
+  //
+  const name_values& rps (rq.parameters (0 /* limit */));
+
+  // If there is no request parameters then we respond with the submission
+  // form XHTML, if configured. Otherwise, will proceed as for the submission
+  // request and will fail (missing parameters).
+  //
+  if (rps.empty () && form_ != nullptr)
+  {
+    const string title ("Submit");
+
+    xml::serializer s (rs.content (), title);
+
+    s << HTML
+      <<   HEAD
+      <<     TITLE << title << ~TITLE
+      <<     CSS_LINKS (path ("submit.css"), root)
+      <<   ~HEAD
+      <<   BODY
+      <<     DIV_HEADER (root, options_->logo (), options_->menu ())
+      <<     DIV(ID="content") << *form_ << ~DIV
+      <<   ~BODY
+      << ~HTML;
+
+    return true;
+  }
+
+  // Verify the submission parameters we expect. The unknown ones will be
+  // serialized to the submission manifest.
+  //
+  params::submit params;
+
+  try
+  {
+    name_value_scanner s (rps);
+    params = params::submit (s, unknown_mode::skip, unknown_mode::skip);
+  }
+  catch (const cli::exception&)
+  {
+    return respond_manifest (400, "invalid parameter");
+  }
+
+  const string& archive (params.archive ());
+  const string& sha256sum (params.sha256sum ());
+
+  if (archive.empty ())
+    return respond_manifest (400, "package archive expected");
+
+  if (sha256sum.empty ())
+    return respond_manifest (400, "package archive checksum expected");
+
+  if (sha256sum.size () != 64)
+    return respond_manifest (400, "invalid package archive checksum");
+
+  // Verify that unknown parameter values satisfy the requirements (contain
+  // only ASCII printable characters plus '\r', '\n', and '\t').
+  //
+  // Actually, the expected ones must satisfy too, so check them as well.
+  //
+  auto printable = [] (const string& s) -> bool
+  {
+    for (char c: s)
+    {
+      if (!((c >= 0x20 && c <= 0x7E) || c == '\n' || c == '\r' || c == '\t'))
+        return false;
+    }
+    return true;
+  };
+
+  for (const name_value& nv: rps)
+  {
+    if (nv.value && !printable (*nv.value))
+      return respond_manifest (400, "invalid parameter " + nv.name);
+  }
+
+  // Check for a duplicate submission.
+  //
+  // Respond with the conflict (409) code if a duplicate is found.
+  //
+  string ac (sha256sum, 0, 12);
+  dir_path dd (options_->submit_data () / dir_path (ac));
+
+  if (dir_exists (dd))
+    return respond_manifest (409, "duplicate submission");
+
+  // Create the temporary submission directory.
+  //
+  dir_path td;
+
+  try
+  {
+    // Note that providing a meaningful prefix for temp_name() is not really
+    // required as the temporary directory is used by brep exclusively. However,
+    // using the abbreviated checksum can be helpful for troubleshooting.
+    //
+    td = dir_path (options_->submit_temp () /
+                   dir_path (path::traits::temp_name (ac)));
+
+    // It's highly unlikely but still possible that the temporary directory
+    // already exists. This can only happen due to the unclean web server
+    // shutdown. Let's remove it and retry.
+    //
+    if (try_mkdir (td) == mkdir_status::already_exists)
+    {
+      try_rmdir_r (td);
+
+      if (try_mkdir (td) == mkdir_status::already_exists)
+        throw_generic_error (EEXIST);
+    }
+  }
+  catch (const invalid_path&)
+  {
+    return respond_manifest (400, "invalid package archive checksum");
+  }
+  catch (const system_error& e)
+  {
+    error << "unable to create directory '" << td << "': " << e;
+    return respond_error ();
+  }
+
+  auto_rmdir tdr (td);
+
+  // Save the package archive into the temporary directory and verify its
+  // checksum.
+  //
+  // Note that the archive file name can potentially contain directory path
+  // in the client's form (e.g., Windows), so let's strip it if that's the
+  // case.
+  //
+  path a;
+  path af;
+
+  try
+  {
+    size_t n (archive.find_last_of ("\\/"));
+    a = path (n != string::npos ? string (archive, n + 1) : archive);
+    af = td / a;
+  }
+  catch (const invalid_path&)
+  {
+    return respond_manifest (400, "invalid package archive name");
+  }
+
+  try
+  {
+    istream& is (rq.open_upload ("archive"));
+
+    // Note that istream::read() sets failbit if unable to read the requested
+    // number of bytes.
+    //
+    is.exceptions (istream::badbit);
+
+    sha256 sha;
+    char buf[8192];
+    ofdstream os (af, ios::binary);
+
+    while (!eof (is))
+    {
+      is.read (buf, sizeof (buf));
+
+      if (size_t n = is.gcount ())
+      {
+        sha.append (buf, n);
+        os.write (buf, n);
+      }
+    }
+
+    os.close ();
+
+    if (sha.string () != sha256sum)
+      return respond_manifest (400, "package archive checksum mismatch");
+  }
+  // Note that invalid_argument (thrown by open_upload() function call) can
+  // mean both no archive upload or multiple archive uploads.
+  //
+  catch (const invalid_argument&)
+  {
+    return respond_manifest (400, "package archive upload expected");
+  }
+  catch (const io_error& e)
+  {
+    error << "unable to write package archive '" << af << "': " << e;
+    return respond_error ();
+  }
+
+  // Serialize the submission request manifest to a stream. On the
+  // serialization error respond to the client with the manifest containing
+  // the bad request (400) code and return false, on the stream error pass
+  // through the io_error exception, otherwise return true.
+  //
+  timestamp ts (system_clock::now ());
+
+  auto rqm = [&a, &sha256sum, &ts, &rq, &rps, &respond_manifest]
+             (ostream& os) -> bool
+  {
+    try
+    {
+      serializer s (os, "request");
+
+      // Serialize the submission manifest header.
+      //
+      s.next ("", "1");                // Start of manifest.
+      s.next ("archive", a.string ());
+      s.next ("sha256sum", sha256sum);
+
+      s.next ("timestamp",
+              butl::to_string (ts,
+                               "%Y-%m-%dT%H:%M:%SZ",
+                               false /* special */,
+                               false /* local */));
+
+      // Serialize the User-Agent HTTP header and the client IP address.
+      //
+      optional<string> ip;
+      optional<string> ua;
+      for (const name_value& h: rq.headers ())
+      {
+        if (casecmp (h.name, ":Client-IP") == 0)
+          ip = h.value;
+        else if (casecmp (h.name, "User-Agent") == 0)
+          ua = h.value;
+      }
+
+      if (ip)
+        s.next ("client-ip", *ip);
+
+      if (ua)
+        s.next ("user-agent", *ua);
+
+      // Serialize the request parameters.
+      //
+      // Note that the serializer constraints the parameter names (can't start
+      // with '#', can't contain ':' and the whitespaces, etc.).
+      //
+      for (const name_value& nv: rps)
+      {
+        const string& n (nv.name);
+        if (n != "archive" && n != "sha256sum")
+          s.next (n, nv.value ? *nv.value : "");
+      }
+
+      s.next ("", ""); // End of manifest.
+      return true;
+    }
+    catch (const serialization& e)
+    {
+      respond_manifest (400, string ("invalid parameter: ") + e.what ());
+      return false;
+    }
+  };
+
+  // Serialize the submission request manifest to the temporary submission
+  // directory.
+  //
+  path rqf (td / "request.manifest");
+
+  try
+  {
+    ofdstream os (rqf);
+    bool r (rqm (os));
+    os.close ();
+
+    if (!r)
+      return true; // The client is already responded with the manifest.
+  }
+  catch (const io_error& e)
+  {
+    error << "unable to write to '" << rqf << "': " << e;
+    return respond_error ();
+  }
+
+  // Make the temporary submission directory permanent.
+  //
+  // Respond with the conflict (409) code if a submission race is detected.
+  //
+  try
+  {
+    mvdir (td, dd);
+  }
+  catch (const system_error& e)
+  {
+    int ec (e.code ().value ());
+    if (ec == ENOTEMPTY || ec == EEXIST)
+      return respond_manifest (409, "duplicate submission");
+
+    error << "unable to rename directory '" << td << "' to '" << dd << "': "
+          << e;
+
+    return respond_error ();
+  }
+
+  // Given that the submission data is now successfully persisted we are no
+  // longer in charge of removing it, even in case of a subsequent error.
+  //
+  tdr.cancel ();
+
+  auto print_args = [&trace, this] (const char* args[], size_t n)
+  {
+    l2 ([&]{trace << process_args {args, n};});
+  };
+
+  // Run the submission handler, if specified, reading the result manifest
+  // from its stdout and caching it as a name/value pair list for later use
+  // (forwarding to the client, sending via email, etc.).
+  //
+  // Note that if the handler is configured then the cache can never be empty,
+  // containing at least the status value. Thus, an empty cache indicates that
+  // the handler is not configured.
+  //
+  status_code sc;
+  vector<manifest_name_value> rvs;
+
+  if (options_->submit_handler_specified ())
+  {
+    const path& handler (options_->submit_handler ());
+
+    for (;;) // Breakout loop.
+    try
+    {
+      fdpipe pipe (fdopen_pipe ()); // Can throw io_error.
+
+      // Redirect the diagnostics to the web server error log.
+      //
+      process pr (
+        process_start_callback (print_args,
+                                0     /* stdin  */,
+                                pipe  /* stdout */,
+                                2     /* stderr */,
+                                handler,
+                                options_->submit_handler_argument (),
+                                dd));
+      pipe.out.close ();
+
+      try
+      {
+        ifdstream is (move (pipe.in));
+
+        // Parse and verify the manifest. Obtain the HTTP status code (must go
+        // first) and cache it for the subsequent responding to the client.
+        //
+        parser p (is, "handler");
+        manifest_name_value nv (p.next ());
+
+        auto bad_name ([&p, &nv] (const string& d) {
+            throw parsing (p.name (), nv.name_line, nv.name_column, d);});
+
+        auto bad_value ([&p, &nv] (const string& d) {
+            throw parsing (p.name (), nv.value_line, nv.value_column, d);});
+
+        const string& n (nv.name);
+        const string& v (nv.value);
+
+        // Make sure this is the start and we support the version.
+        //
+        if (!n.empty ())
+          bad_name ("start of manifest expected");
+
+        if (v != "1")
+          bad_value ("unsupported format version");
+
+        // Cache start of manifest.
+        //
+        rvs.push_back (move (nv));
+
+        // Get and verify the HTTP status.
+        //
+        nv = p.next ();
+        if (n != "status")
+          bad_value ("no status specified");
+
+        char* e (nullptr);
+        unsigned long c (strtoul (v.c_str (), &e, 10)); // Can't throw.
+
+        assert (e != nullptr);
+
+        if (!(*e == '\0' && c >= 100 && c < 600))
+          bad_value ("invalid http status '" + v + "'");
+
+        // Cache the HTTP status.
+        //
+        sc = static_cast<status_code> (c);
+        rvs.push_back (move (nv));
+
+        // Cache the remaining name/value pairs.
+        //
+        for (nv = p.next (); !nv.empty (); nv = p.next ())
+          rvs.push_back (move (nv));
+
+        // Cache end of manifest.
+        //
+        rvs.push_back (move (nv));
+
+        is.close ();
+
+        if (pr.wait ())
+          break; // Get out of the breakout loop.
+
+        assert (pr.exit);
+        error << "process " << handler << " " << *pr.exit;
+
+        // Fall through.
+      }
+      catch (const parsing& e)
+      {
+        if (pr.wait ())
+          error << "unable to parse handler's output: " << e;
+
+        // Fall through.
+      }
+      catch (const io_error& e)
+      {
+        if (pr.wait ())
+          error << "unable to read handler's output: " << e;
+
+        // Fall through.
+      }
+
+      return respond_error ();
+    }
+    // Handle process_error and io_error (both derive from system_error).
+    //
+    catch (const system_error& e)
+    {
+      error << "unable to execute '" << handler << "': " << e;
+      return respond_error ();
+    }
+  }
+
+  // Serialize the submission result manifest to a stream. On the
+  // serialization error log the error description and return false, on the
+  // stream error pass through the io_error exception, otherwise return true.
+  //
+  auto rsm = [&rvs, &error] (ostream& os) -> bool
+  {
+    assert (!rvs.empty ());
+
+    try
+    {
+      serializer s (os, "result");
+      for (const manifest_name_value& nv: rvs)
+        s.next (nv.name, nv.value);
+
+      return true;
+    }
+    catch (const serialization& e)
+    {
+      error << "unable to serialize handler's output: " << e;
+      return false;
+    }
+  };
+
+  // Save the result manifest, if generated, into the submission directory
+  // if it still exists (note that the handler could move or remove it).
+  //
+  path rsf (dd / "result.manifest");
+
+  if (!rvs.empty () && dir_exists (dd))
+  try
+  {
+    ofdstream os (rsf);
+    bool r (rsm (os));
+    os.close ();
+
+    if (!r)
+      return respond_error (); // The error description is already logged.
+  }
+  catch (const io_error& e)
+  {
+    error << "unable to write to '" << rsf << "': " << e;
+    return respond_error ();
+  }
+
+  // Send email, if configured.
+  //
+  // Note that we don't consider the email sending failure to be a submission
+  // failure as the submission data is successfully persisted and the handler
+  // is successfully executed, if configured. One can argue that email can be
+  // essential for the submission processing and missing it would result in
+  // the incomplete submission. In this case it's natural to assume that the
+  // web server error log is monitored and the email sending failure will be
+  // noticed.
+  //
+  if (options_->submit_email_specified ())
+  try
+  {
+    // Redirect the diagnostics to the web server error log.
+    //
+    sendmail sm (print_args,
+                 2 /* stderr */,
+                 options_->email (),
+                 "new package submission " + a.string () + " (" + ac + ")",
+                 {options_->submit_email ()});
+
+    // Write the submission request manifest.
+    //
+    bool r (rqm (sm.out));
+    assert (r); // The serialization succeeded once, so can't fail now.
+
+    // Write the submission result manifest, if present.
+    //
+    if (!rvs.empty ())
+    {
+      sm.out << "\n\n";
+
+      rsm (sm.out); // We don't care about the result (see above).
+    }
+
+    sm.out.close ();
+
+    if (!sm.wait ())
+      error << "sendmail " << *sm.exit;
+  }
+  // Handle process_error and io_error (both derive from system_error).
+  //
+  catch (const system_error& e)
+  {
+    error << "sendmail error: " << e;
+  }
+
+  // Respond with implied result manifest if the handler is not configured.
+  //
+  if (rvs.empty ())
+    return respond_manifest (200, "submission queued", ac.c_str ());
+
+  if (!rsm (rs.content (sc, "text/manifest;charset=utf-8")))
+    return respond_error (); // The error description is already logged.
+
+  return true;
+}