nix/libstore/builtins.cc

   1 /* GNU Guix --- Functional package management for GNU
   2    Copyright (C) 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
   3
   4    This file is part of GNU Guix.
   5
   6    GNU Guix is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or (at
   9    your option) any later version.
  10
  11    GNU Guix is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <builtins.hh>
  20 #include <util.hh>
  21 #include <globals.hh>
  22
  23 #include <unistd.h>
  24 #include <cstdlib>
  25
  26 namespace nix {
  27
  28 static void builtinDownload(const Derivation &drv,
  29                             const std::string &drvPath,
  30                             const std::string &output)
  31 {
  32     /* Invoke 'guix perform-download'.  */
  33     Strings args;
  34     args.push_back("perform-download");
  35     args.push_back(drvPath);
  36
  37     /* Close all other file descriptors. */
  38     closeMostFDs(set<int>());
  39
  40     const char *const argv[] =
  41       {
  42         "download", drvPath.c_str(), output.c_str(), NULL
  43       };
  44
  45     /* Tell the script what the store file name is, so that
  46        'strip-store-file-name' (used for instance to determine the URL of
  47        content-addressed mirrors) works correctly.  */
  48     setenv("NIX_STORE", settings.nixStore.c_str(), 1);
  49
  50     /* Tell it about options such as "print-extended-build-trace".  */
  51     setenv("_NIX_OPTIONS", settings.pack().c_str(), 1);
  52
  53     const string program = settings.nixLibexecDir + "/download";
  54     execv(program.c_str(), (char *const *) argv);
  55
  56     throw SysError(format("failed to run download program '%1%'") % program);
  57 }
  58
  59 static const std::map<std::string, derivationBuilder> builtins =
  60 {
  61     { "download", builtinDownload }
  62 };
  63
  64 derivationBuilder lookupBuiltinBuilder(const std::string & name)
  65 {
  66     if (name.substr(0, 8) == "builtin:")
  67     {
  68         auto realName = name.substr(8);
  69         auto builder = builtins.find(realName);
  70         return builder == builtins.end() ? NULL : builder->second;
  71     }
  72     else
  73         return NULL;
  74 }
  75
  76 std::list<std::string> builtinBuilderNames()
  77 {
  78     std::list<std::string> result;
  79     for(auto&& iter: builtins)
  80     {
  81         result.push_back(iter.first);
  82     }
  83     return result;
  84 }
  85
  86 }