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#include <algorithm>
#include <absl/strings/match.h>
#include <absl/strings/str_split.h>
#include <fcntl.h>
#include <glog/logging.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "libstore/builtins.hh"
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) {
LOG(ERROR) << "warning: not including '" << srcDir
<< "' in the user environment because it's not a directory";
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) {
LOG(ERROR) << "warning: skipping dangling symlink '" << 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 (absl::EndsWith(srcFile, "/propagated-build-inputs") ||
absl::EndsWith(srcFile, "/nix-support") ||
absl::EndsWith(srcFile, "/perllocal.pod") ||
absl::EndsWith(srcFile, "/info/dir") ||
absl::EndsWith(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 (auto p : absl::StrSplit(
readFile(pkgDir + "/nix-support/propagated-user-env-packages"),
absl::ByAnyChar(" \n"))) {
auto pkg = std::string(p);
if (!done.count(pkg)) {
postponed.insert(pkg);
}
}
} 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 std::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;
Strings derivations =
absl::StrSplit(getAttr("derivations"), absl::ByAnyChar(" \t\n\r"));
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++);
}
}
LOG(INFO) << "created " << symlinks << " symlinks in user environment";
createSymlink(getAttr("manifest"), out + "/manifest.nix");
}
} // namespace nix
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