1 #include "primops.hh"
2 #include "eval-inline.hh"
3 #include "download.hh"
4 #include "store-api.hh"
5 #include "pathlocks.hh"
6 #include "hash.hh"
7 
8 #include <sys/time.h>
9 #include <sys/wait.h>
10 
11 #include <regex>
12 
13 #include <nlohmann/json.hpp>
14 
15 using namespace std::string_literals;
16 
17 namespace nix {
18 
19 struct GitInfo
20 {
21     Path storePath;
22     std::string rev;
23     std::string shortRev;
24     uint64_t revCount = 0;
25 };
26 
27 std::regex revRegex("^[0-9a-fA-F]{40}$");
28 
exportGit(ref<Store> store,const std::string & uri,std::optional<std::string> ref,std::string rev,const std::string & name)29 GitInfo exportGit(ref<Store> store, const std::string & uri,
30     std::optional<std::string> ref, std::string rev,
31     const std::string & name)
32 {
33     if (evalSettings.pureEval && rev == "")
34         throw Error("in pure evaluation mode, 'fetchGit' requires a Git revision");
35 
36     if (!ref && rev == "" && hasPrefix(uri, "/") && pathExists(uri + "/.git")) {
37 
38         bool clean = true;
39 
40         try {
41             runProgram("git", true, { "-C", uri, "diff-index", "--quiet", "HEAD", "--" });
42         } catch (ExecError & e) {
43             if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) throw;
44             clean = false;
45         }
46 
47         if (!clean) {
48 
49             /* This is an unclean working tree. So copy all tracked
50                files. */
51 
52             GitInfo gitInfo;
53             gitInfo.rev = "0000000000000000000000000000000000000000";
54             gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);
55 
56             auto files = tokenizeString<std::set<std::string>>(
57                 runProgram("git", true, { "-C", uri, "ls-files", "-z" }), "\0"s);
58 
59             PathFilter filter = [&](const Path & p) -> bool {
60                 assert(hasPrefix(p, uri));
61                 std::string file(p, uri.size() + 1);
62 
63                 auto st = lstat(p);
64 
65                 if (S_ISDIR(st.st_mode)) {
66                     auto prefix = file + "/";
67                     auto i = files.lower_bound(prefix);
68                     return i != files.end() && hasPrefix(*i, prefix);
69                 }
70 
71                 return files.count(file);
72             };
73 
74             gitInfo.storePath = store->addToStore("source", uri, true, htSHA256, filter);
75 
76             return gitInfo;
77         }
78 
79         // clean working tree, but no ref or rev specified.  Use 'HEAD'.
80         rev = chomp(runProgram("git", true, { "-C", uri, "rev-parse", "HEAD" }));
81         ref = "HEAD"s;
82     }
83 
84     if (!ref) ref = "HEAD"s;
85 
86     if (rev != "" && !std::regex_match(rev, revRegex))
87         throw Error("invalid Git revision '%s'", rev);
88 
89     deletePath(getCacheDir() + "/nix/git");
90 
91     Path cacheDir = getCacheDir() + "/nix/gitv2/" + hashString(htSHA256, uri).to_string(Base32, false);
92 
93     if (!pathExists(cacheDir)) {
94         createDirs(dirOf(cacheDir));
95         runProgram("git", true, { "init", "--bare", cacheDir });
96     }
97 
98     Path localRefFile;
99     if (ref->compare(0, 5, "refs/") == 0)
100         localRefFile = cacheDir + "/" + *ref;
101     else
102         localRefFile = cacheDir + "/refs/heads/" + *ref;
103 
104     bool doFetch;
105     time_t now = time(0);
106     /* If a rev was specified, we need to fetch if it's not in the
107        repo. */
108     if (rev != "") {
109         try {
110             runProgram("git", true, { "-C", cacheDir, "cat-file", "-e", rev });
111             doFetch = false;
112         } catch (ExecError & e) {
113             if (WIFEXITED(e.status)) {
114                 doFetch = true;
115             } else {
116                 throw;
117             }
118         }
119     } else {
120         /* If the local ref is older than ‘tarball-ttl’ seconds, do a
121            git fetch to update the local ref to the remote ref. */
122         struct stat st;
123         doFetch = stat(localRefFile.c_str(), &st) != 0 ||
124             (uint64_t) st.st_mtime + settings.tarballTtl <= (uint64_t) now;
125     }
126     if (doFetch)
127     {
128         Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Git repository '%s'", uri));
129 
130         // FIXME: git stderr messes up our progress indicator, so
131         // we're using --quiet for now. Should process its stderr.
132         runProgram("git", true, { "-C", cacheDir, "fetch", "--quiet", "--force", "--", uri, fmt("%s:%s", *ref, *ref) });
133 
134         struct timeval times[2];
135         times[0].tv_sec = now;
136         times[0].tv_usec = 0;
137         times[1].tv_sec = now;
138         times[1].tv_usec = 0;
139 
140         utimes(localRefFile.c_str(), times);
141     }
142 
143     // FIXME: check whether rev is an ancestor of ref.
144     GitInfo gitInfo;
145     gitInfo.rev = rev != "" ? rev : chomp(readFile(localRefFile));
146     gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);
147 
148     printTalkative("using revision %s of repo '%s'", gitInfo.rev, uri);
149 
150     std::string storeLinkName = hashString(htSHA512, name + std::string("\0"s) + gitInfo.rev).to_string(Base32, false);
151     Path storeLink = cacheDir + "/" + storeLinkName + ".link";
152     PathLocks storeLinkLock({storeLink}, fmt("waiting for lock on '%1%'...", storeLink)); // FIXME: broken
153 
154     try {
155         auto json = nlohmann::json::parse(readFile(storeLink));
156 
157         assert(json["name"] == name && json["rev"] == gitInfo.rev);
158 
159         gitInfo.storePath = json["storePath"];
160 
161         if (store->isValidPath(gitInfo.storePath)) {
162             gitInfo.revCount = json["revCount"];
163             return gitInfo;
164         }
165 
166     } catch (SysError & e) {
167         if (e.errNo != ENOENT) throw;
168     }
169 
170     // FIXME: should pipe this, or find some better way to extract a
171     // revision.
172     auto tar = runProgram("git", true, { "-C", cacheDir, "archive", gitInfo.rev });
173 
174     Path tmpDir = createTempDir();
175     AutoDelete delTmpDir(tmpDir, true);
176 
177     runProgram("tar", true, { "x", "-C", tmpDir, "-f", "-"}, tar);
178 
179     gitInfo.storePath = store->addToStore(name, tmpDir);
180 
181     gitInfo.revCount = std::stoull(runProgram("git", true, { "-C", cacheDir, "rev-list", "--count", gitInfo.rev }));
182 
183     nlohmann::json json;
184     json["storePath"] = gitInfo.storePath;
185     json["uri"] = uri;
186     json["name"] = name;
187     json["rev"] = gitInfo.rev;
188     json["revCount"] = gitInfo.revCount;
189 
190     writeFile(storeLink, json.dump());
191 
192     return gitInfo;
193 }
194 
prim_fetchGit(EvalState & state,const Pos & pos,Value ** args,Value & v)195 static void prim_fetchGit(EvalState & state, const Pos & pos, Value * * args, Value & v)
196 {
197     std::string url;
198     std::optional<std::string> ref;
199     std::string rev;
200     std::string name = "source";
201     PathSet context;
202 
203     state.forceValue(*args[0]);
204 
205     if (args[0]->type == tAttrs) {
206 
207         state.forceAttrs(*args[0], pos);
208 
209         for (auto & attr : *args[0]->attrs) {
210             string n(attr.name);
211             if (n == "url")
212                 url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
213             else if (n == "ref")
214                 ref = state.forceStringNoCtx(*attr.value, *attr.pos);
215             else if (n == "rev")
216                 rev = state.forceStringNoCtx(*attr.value, *attr.pos);
217             else if (n == "name")
218                 name = state.forceStringNoCtx(*attr.value, *attr.pos);
219             else
220                 throw EvalError("unsupported argument '%s' to 'fetchGit', at %s", attr.name, *attr.pos);
221         }
222 
223         if (url.empty())
224             throw EvalError(format("'url' argument required, at %1%") % pos);
225 
226     } else
227         url = state.coerceToString(pos, *args[0], context, false, false);
228 
229     // FIXME: git externals probably can be used to bypass the URI
230     // whitelist. Ah well.
231     state.checkURI(url);
232 
233     auto gitInfo = exportGit(state.store, url, ref, rev, name);
234 
235     state.mkAttrs(v, 8);
236     mkString(*state.allocAttr(v, state.sOutPath), gitInfo.storePath, PathSet({gitInfo.storePath}));
237     mkString(*state.allocAttr(v, state.symbols.create("rev")), gitInfo.rev);
238     mkString(*state.allocAttr(v, state.symbols.create("shortRev")), gitInfo.shortRev);
239     mkInt(*state.allocAttr(v, state.symbols.create("revCount")), gitInfo.revCount);
240     v.attrs->sort();
241 
242     if (state.allowedPaths)
243         state.allowedPaths->insert(state.store->toRealPath(gitInfo.storePath));
244 }
245 
246 static RegisterPrimOp r("fetchGit", 1, prim_fetchGit);
247 
248 }
249