diff options
Diffstat (limited to 'third_party/nix/src/libstore/builtins/buildenv.cc')
| -rw-r--r-- | third_party/nix/src/libstore/builtins/buildenv.cc | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/builtins/buildenv.cc b/third_party/nix/src/libstore/builtins/buildenv.cc new file mode 100644 index 000000000000..74e706664694 --- /dev/null +++ b/third_party/nix/src/libstore/builtins/buildenv.cc @@ -0,0 +1,204 @@ +#include "builtins.hh" + +#include <sys/stat.h> +#include <sys/types.h> +#include <fcntl.h> +#include <algorithm> + +namespace nix { + +typedef std::map<Path,int> Priorities; + +// FIXME: change into local variables. + +static Priorities priorities; + +static unsigned long symlinks; + +/* For each activated package, create symlinks */ +static void createLinks(const Path & srcDir, const Path & dstDir, int priority) +{ + DirEntries srcFiles; + + try { + srcFiles = readDirectory(srcDir); + } catch (SysError & e) { + if (e.errNo == ENOTDIR) { + printError("warning: not including '%s' in the user environment because it's not a directory", srcDir); + return; + } + throw; + } + + for (const auto & ent : srcFiles) { + if (ent.name[0] == '.') + /* not matched by glob */ + continue; + auto srcFile = srcDir + "/" + ent.name; + auto dstFile = dstDir + "/" + ent.name; + + struct stat srcSt; + try { + if (stat(srcFile.c_str(), &srcSt) == -1) + throw SysError("getting status of '%1%'", srcFile); + } catch (SysError & e) { + if (e.errNo == ENOENT || e.errNo == ENOTDIR) { + printError("warning: skipping dangling symlink '%s'", dstFile); + continue; + } + throw; + } + + /* The files below are special-cased to that they don't show up + * in user profiles, either because they are useless, or + * because they would cauase pointless collisions (e.g., each + * Python package brings its own + * `$out/lib/pythonX.Y/site-packages/easy-install.pth'.) + */ + if (hasSuffix(srcFile, "/propagated-build-inputs") || + hasSuffix(srcFile, "/nix-support") || + hasSuffix(srcFile, "/perllocal.pod") || + hasSuffix(srcFile, "/info/dir") || + hasSuffix(srcFile, "/log")) + continue; + + else if (S_ISDIR(srcSt.st_mode)) { + struct stat dstSt; + auto res = lstat(dstFile.c_str(), &dstSt); + if (res == 0) { + if (S_ISDIR(dstSt.st_mode)) { + createLinks(srcFile, dstFile, priority); + continue; + } else if (S_ISLNK(dstSt.st_mode)) { + auto target = canonPath(dstFile, true); + if (!S_ISDIR(lstat(target).st_mode)) + throw Error("collision between '%1%' and non-directory '%2%'", srcFile, target); + if (unlink(dstFile.c_str()) == -1) + throw SysError(format("unlinking '%1%'") % dstFile); + if (mkdir(dstFile.c_str(), 0755) == -1) + throw SysError(format("creating directory '%1%'")); + createLinks(target, dstFile, priorities[dstFile]); + createLinks(srcFile, dstFile, priority); + continue; + } + } else if (errno != ENOENT) + throw SysError(format("getting status of '%1%'") % dstFile); + } + + else { + struct stat dstSt; + auto res = lstat(dstFile.c_str(), &dstSt); + if (res == 0) { + if (S_ISLNK(dstSt.st_mode)) { + auto prevPriority = priorities[dstFile]; + if (prevPriority == priority) + throw Error( + "packages '%1%' and '%2%' have the same priority %3%; " + "use 'nix-env --set-flag priority NUMBER INSTALLED_PKGNAME' " + "to change the priority of one of the conflicting packages" + " (0 being the highest priority)", + srcFile, readLink(dstFile), priority); + if (prevPriority < priority) + continue; + if (unlink(dstFile.c_str()) == -1) + throw SysError(format("unlinking '%1%'") % dstFile); + } else if (S_ISDIR(dstSt.st_mode)) + throw Error("collision between non-directory '%1%' and directory '%2%'", srcFile, dstFile); + } else if (errno != ENOENT) + throw SysError(format("getting status of '%1%'") % dstFile); + } + + createSymlink(srcFile, dstFile); + priorities[dstFile] = priority; + symlinks++; + } +} + +typedef std::set<Path> FileProp; + +static FileProp done; +static FileProp postponed = FileProp{}; + +static Path out; + +static void addPkg(const Path & pkgDir, int priority) +{ + if (done.count(pkgDir)) return; + done.insert(pkgDir); + createLinks(pkgDir, out, priority); + + try { + for (const auto & p : tokenizeString<std::vector<string>>( + readFile(pkgDir + "/nix-support/propagated-user-env-packages"), " \n")) + if (!done.count(p)) + postponed.insert(p); + } catch (SysError & e) { + if (e.errNo != ENOENT && e.errNo != ENOTDIR) throw; + } +} + +struct Package { + Path path; + bool active; + int priority; + Package(Path path, bool active, int priority) : path{path}, active{active}, priority{priority} {} +}; + +typedef std::vector<Package> Packages; + +void builtinBuildenv(const BasicDerivation & drv) +{ + auto getAttr = [&](const string & name) { + auto i = drv.env.find(name); + if (i == drv.env.end()) throw Error("attribute '%s' missing", name); + return i->second; + }; + + out = getAttr("out"); + createDirs(out); + + /* Convert the stuff we get from the environment back into a + * coherent data type. */ + Packages pkgs; + auto derivations = tokenizeString<Strings>(getAttr("derivations")); + while (!derivations.empty()) { + /* !!! We're trusting the caller to structure derivations env var correctly */ + auto active = derivations.front(); derivations.pop_front(); + auto priority = stoi(derivations.front()); derivations.pop_front(); + auto outputs = stoi(derivations.front()); derivations.pop_front(); + for (auto n = 0; n < outputs; n++) { + auto path = derivations.front(); derivations.pop_front(); + pkgs.emplace_back(path, active != "false", priority); + } + } + + /* Symlink to the packages that have been installed explicitly by the + * user. Process in priority order to reduce unnecessary + * symlink/unlink steps. + */ + std::sort(pkgs.begin(), pkgs.end(), [](const Package & a, const Package & b) { + return a.priority < b.priority || (a.priority == b.priority && a.path < b.path); + }); + for (const auto & pkg : pkgs) + if (pkg.active) + addPkg(pkg.path, pkg.priority); + + /* Symlink to the packages that have been "propagated" by packages + * installed by the user (i.e., package X declares that it wants Y + * installed as well). We do these later because they have a lower + * priority in case of collisions. + */ + auto priorityCounter = 1000; + while (!postponed.empty()) { + auto pkgDirs = postponed; + postponed = FileProp{}; + for (const auto & pkgDir : pkgDirs) + addPkg(pkgDir, priorityCounter++); + } + + printError("created %d symlinks in user environment", symlinks); + + createSymlink(getAttr("manifest"), out + "/manifest.nix"); +} + +} |