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#include "shared.hh"
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <algorithm>
using namespace nix;
typedef std::map<Path,int> Priorities;
static bool isDirectory (const Path & path)
{
struct stat st;
if (stat(path.c_str(), &st) == -1)
throw SysError(format("getting status of '%1%'") % path);
return S_ISDIR(st.st_mode);
}
static auto priorities = Priorities{};
static auto symlinks = 0;
/* For each activated package, create symlinks */
static void createLinks(const Path & srcDir, const Path & dstDir, int priority)
{
auto srcFiles = readDirectory(srcDir);
for (const auto & ent : srcFiles) {
if (ent.name[0] == '.')
/* not matched by glob */
continue;
const auto & srcFile = srcDir + "/" + ent.name;
auto dstFile = dstDir + "/" + ent.name;
/* 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 (isDirectory(srcFile)) {
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 = readLink(dstFile);
if (!isDirectory(target))
throw Error(format("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 target = readLink(dstFile);
auto prevPriority = priorities[dstFile];
if (prevPriority == priority)
throw Error(format(
"collision between '%1%' and '%2%'; "
"use 'nix-env --set-flag priority NUMBER PKGNAME' "
"to change the priority of one of the conflicting packages"
) % srcFile % target);
if (prevPriority < priority)
continue;
if (unlink(dstFile.c_str()) == -1)
throw SysError(format("unlinking '%1%'") % 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 auto done = FileProp{};
static auto postponed = FileProp{};
static auto out = string{};
static void addPkg(const Path & pkgDir, int priority)
{
if (done.find(pkgDir) != done.end())
return;
done.insert(pkgDir);
createLinks(pkgDir, out, priority);
auto propagatedFN = pkgDir + "/nix-support/propagated-user-env-packages";
auto propagated = string{};
{
AutoCloseFD fd = open(propagatedFN.c_str(), O_RDONLY | O_CLOEXEC);
if (!fd) {
if (errno == ENOENT)
return;
throw SysError(format("opening '%1%'") % propagatedFN);
}
propagated = readLine(fd.get());
}
for (const auto & p : tokenizeString<std::vector<string>>(propagated, " "))
if (done.find(p) == done.end())
postponed.insert(p);
}
struct Package {
Path path;
bool active;
int priority;
Package(Path path, bool active, int priority) : path{std::move(path)}, active{active}, priority{priority} {}
};
typedef std::vector<Package> Packages;
int main(int argc, char ** argv)
{
return handleExceptions(argv[0], [&]() {
initNix();
out = getEnv("out");
if (mkdir(out.c_str(), 0755) == -1)
throw SysError(format("creating %1%") % out);
/* Convert the stuff we get from the environment back into a coherent
* data type.
*/
auto pkgs = Packages{};
auto derivations = tokenizeString<Strings>(getEnv("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++);
}
std::cerr << "created " << symlinks << " symlinks in user environment\n";
createSymlink(getEnv("manifest"), out + "/manifest.nix");
});
}
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