about summary refs log tree commit diff
path: root/third_party/nix/src/libexpr/primops/fetchGit.cc
blob: 7ef3dea8eef688e3a9ac4ee58047b88b33b3487e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
#include <nlohmann/json.hpp>
#include <regex>

#include <glog/logging.h>
#include <sys/time.h>

#include "download.hh"
#include "eval-inline.hh"
#include "hash.hh"
#include "pathlocks.hh"
#include "primops.hh"
#include "store-api.hh"

using namespace std::string_literals;

namespace nix {

struct GitInfo {
  Path storePath;
  std::string rev;
  std::string shortRev;
  uint64_t revCount = 0;
};

std::regex revRegex("^[0-9a-fA-F]{40}$");

GitInfo exportGit(ref<Store> store, const std::string& uri,
                  std::optional<std::string> ref, std::string rev,
                  const std::string& name) {
  if (evalSettings.pureEval && rev == "")
    throw Error("in pure evaluation mode, 'fetchGit' requires a Git revision");

  if (!ref && rev == "" && hasPrefix(uri, "/") && pathExists(uri + "/.git")) {
    bool clean = true;

    try {
      runProgram("git", true,
                 {"-C", uri, "diff-index", "--quiet", "HEAD", "--"});
    } catch (ExecError& e) {
      if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) {
        throw;
      }
      clean = false;
    }

    if (!clean) {
      /* This is an unclean working tree. So copy all tracked
         files. */

      GitInfo gitInfo;
      gitInfo.rev = "0000000000000000000000000000000000000000";
      gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);

      auto files = tokenizeString<std::set<std::string>>(
          runProgram("git", true, {"-C", uri, "ls-files", "-z"}), "\0"s);

      PathFilter filter = [&](const Path& p) -> bool {
        assert(hasPrefix(p, uri));
        std::string file(p, uri.size() + 1);

        auto st = lstat(p);

        if (S_ISDIR(st.st_mode)) {
          auto prefix = file + "/";
          auto i = files.lower_bound(prefix);
          return i != files.end() && hasPrefix(*i, prefix);
        }

        return files.count(file);
      };

      gitInfo.storePath =
          store->addToStore("source", uri, true, htSHA256, filter);

      return gitInfo;
    }

    // clean working tree, but no ref or rev specified.  Use 'HEAD'.
    rev = chomp(runProgram("git", true, {"-C", uri, "rev-parse", "HEAD"}));
    ref = "HEAD"s;
  }

  if (!ref) {
    ref = "HEAD"s;
  }

  if (rev != "" && !std::regex_match(rev, revRegex))
    throw Error("invalid Git revision '%s'", rev);

  deletePath(getCacheDir() + "/nix/git");

  Path cacheDir = getCacheDir() + "/nix/gitv2/" +
                  hashString(htSHA256, uri).to_string(Base32, false);

  if (!pathExists(cacheDir)) {
    createDirs(dirOf(cacheDir));
    runProgram("git", true, {"init", "--bare", cacheDir});
  }

  Path localRefFile;
  if (ref->compare(0, 5, "refs/") == 0)
    localRefFile = cacheDir + "/" + *ref;
  else
    localRefFile = cacheDir + "/refs/heads/" + *ref;

  bool doFetch;
  time_t now = time(0);
  /* If a rev was specified, we need to fetch if it's not in the
     repo. */
  if (rev != "") {
    try {
      runProgram("git", true, {"-C", cacheDir, "cat-file", "-e", rev});
      doFetch = false;
    } catch (ExecError& e) {
      if (WIFEXITED(e.status)) {
        doFetch = true;
      } else {
        throw;
      }
    }
  } else {
    /* If the local ref is older than ‘tarball-ttl’ seconds, do a
       git fetch to update the local ref to the remote ref. */
    struct stat st;
    doFetch = stat(localRefFile.c_str(), &st) != 0 ||
              (uint64_t)st.st_mtime + settings.tarballTtl <= (uint64_t)now;
  }
  if (doFetch) {
    DLOG(INFO) << "fetching Git repository '" << uri << "'";

    // FIXME: git stderr messes up our progress indicator, so
    // we're using --quiet for now. Should process its stderr.
    runProgram("git", true,
               {"-C", cacheDir, "fetch", "--quiet", "--force", "--", uri,
                fmt("%s:%s", *ref, *ref)});

    struct timeval times[2];
    times[0].tv_sec = now;
    times[0].tv_usec = 0;
    times[1].tv_sec = now;
    times[1].tv_usec = 0;

    utimes(localRefFile.c_str(), times);
  }

  // FIXME: check whether rev is an ancestor of ref.
  GitInfo gitInfo;
  gitInfo.rev = rev != "" ? rev : chomp(readFile(localRefFile));
  gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);

  DLOG(INFO) << "using revision " << gitInfo.rev << " of repo '" << uri << "'";

  std::string storeLinkName =
      hashString(htSHA512, name + std::string("\0"s) + gitInfo.rev)
          .to_string(Base32, false);
  Path storeLink = cacheDir + "/" + storeLinkName + ".link";
  PathLocks storeLinkLock({storeLink}, fmt("waiting for lock on '%1%'...",
                                           storeLink));  // FIXME: broken

  try {
    auto json = nlohmann::json::parse(readFile(storeLink));

    assert(json["name"] == name && json["rev"] == gitInfo.rev);

    gitInfo.storePath = json["storePath"];

    if (store->isValidPath(gitInfo.storePath)) {
      gitInfo.revCount = json["revCount"];
      return gitInfo;
    }

  } catch (SysError& e) {
    if (e.errNo != ENOENT) {
      throw;
    }
  }

  // FIXME: should pipe this, or find some better way to extract a
  // revision.
  auto tar = runProgram("git", true, {"-C", cacheDir, "archive", gitInfo.rev});

  Path tmpDir = createTempDir();
  AutoDelete delTmpDir(tmpDir, true);

  runProgram("tar", true, {"x", "-C", tmpDir}, tar);

  gitInfo.storePath = store->addToStore(name, tmpDir);

  gitInfo.revCount = std::stoull(runProgram(
      "git", true, {"-C", cacheDir, "rev-list", "--count", gitInfo.rev}));

  nlohmann::json json;
  json["storePath"] = gitInfo.storePath;
  json["uri"] = uri;
  json["name"] = name;
  json["rev"] = gitInfo.rev;
  json["revCount"] = gitInfo.revCount;

  writeFile(storeLink, json.dump());

  return gitInfo;
}

static void prim_fetchGit(EvalState& state, const Pos& pos, Value** args,
                          Value& v) {
  std::string url;
  std::optional<std::string> ref;
  std::string rev;
  std::string name = "source";
  PathSet context;

  state.forceValue(*args[0]);

  if (args[0]->type == tAttrs) {
    state.forceAttrs(*args[0], pos);

    for (auto& attr : *args[0]->attrs) {
      std::string n(attr.name);
      if (n == "url")
        url =
            state.coerceToString(*attr.pos, *attr.value, context, false, false);
      else if (n == "ref")
        ref = state.forceStringNoCtx(*attr.value, *attr.pos);
      else if (n == "rev")
        rev = state.forceStringNoCtx(*attr.value, *attr.pos);
      else if (n == "name")
        name = state.forceStringNoCtx(*attr.value, *attr.pos);
      else
        throw EvalError("unsupported argument '%s' to 'fetchGit', at %s",
                        attr.name, *attr.pos);
    }

    if (url.empty())
      throw EvalError(format("'url' argument required, at %1%") % pos);

  } else {
    url = state.coerceToString(pos, *args[0], context, false, false);
  }

  // FIXME: git externals probably can be used to bypass the URI
  // whitelist. Ah well.
  state.checkURI(url);

  auto gitInfo = exportGit(state.store, url, ref, rev, name);

  state.mkAttrs(v, 8);
  mkString(*state.allocAttr(v, state.sOutPath), gitInfo.storePath,
           PathSet({gitInfo.storePath}));
  mkString(*state.allocAttr(v, state.symbols.Create("rev")), gitInfo.rev);
  mkString(*state.allocAttr(v, state.symbols.Create("shortRev")),
           gitInfo.shortRev);
  mkInt(*state.allocAttr(v, state.symbols.Create("revCount")),
        gitInfo.revCount);
  v.attrs->sort();

  if (state.allowedPaths)
    state.allowedPaths->insert(state.store->toRealPath(gitInfo.storePath));
}

static RegisterPrimOp r("fetchGit", 1, prim_fetchGit);

}  // namespace nix