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#include "buildenv.hh"
#include "strings.hh"
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <algorithm>
namespace nix {
struct State
{
std::map<Path, int> priorities;
unsigned long symlinks = 0;
};
/* For each activated package, create symlinks */
static void createLinks(State & state, const Path & srcDir, const Path & dstDir, int priority)
{
DirEntries srcFiles;
try {
srcFiles = readDirectory(srcDir);
} catch (SysError & e) {
if (e.errNo == ENOTDIR) {
warn("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) {
warn("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 cause pointless collisions (e.g., each
* Python package brings its own
* `$out/lib/pythonX.Y/site-packages/easy-install.pth'.)
*/
if (srcFile.ends_with("/propagated-build-inputs") ||
srcFile.ends_with("/nix-support") ||
srcFile.ends_with("/perllocal.pod") ||
srcFile.ends_with("/info/dir") ||
srcFile.ends_with("/log") ||
srcFile.ends_with("/manifest.nix") ||
srcFile.ends_with("/manifest.json"))
continue;
else if (S_ISDIR(srcSt.st_mode)) {
auto dstStOpt = maybeLstat(dstFile.c_str());
if (dstStOpt) {
auto & dstSt = *dstStOpt;
if (S_ISDIR(dstSt.st_mode)) {
createLinks(state, 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("unlinking '%1%'", dstFile);
if (mkdir(dstFile.c_str(), 0755) == -1)
throw SysError("creating directory '%1%'", dstFile);
createLinks(state, target, dstFile, state.priorities[dstFile]);
createLinks(state, srcFile, dstFile, priority);
continue;
}
}
}
else {
auto dstStOpt = maybeLstat(dstFile.c_str());
if (dstStOpt) {
auto & dstSt = *dstStOpt;
if (S_ISLNK(dstSt.st_mode)) {
auto prevPriority = state.priorities[dstFile];
if (prevPriority == priority)
throw BuildEnvFileConflictError(
readLink(dstFile),
srcFile,
priority
);
if (prevPriority < priority)
continue;
if (unlink(dstFile.c_str()) == -1)
throw SysError("unlinking '%1%'", dstFile);
} else if (S_ISDIR(dstSt.st_mode))
throw Error("collision between non-directory '%1%' and directory '%2%'", srcFile, dstFile);
}
}
createSymlink(srcFile, dstFile);
state.priorities[dstFile] = priority;
state.symlinks++;
}
}
void buildProfile(const Path & out, Packages && pkgs)
{
State state;
std::set<Path> done, postponed;
auto addPkg = [&](const Path & pkgDir, int priority) {
if (!done.insert(pkgDir).second) return;
createLinks(state, pkgDir, out, priority);
try {
for (const auto & p : tokenizeString<std::vector<std::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;
}
};
/* 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()) {
std::set<Path> pkgDirs;
postponed.swap(pkgDirs);
for (const auto & pkgDir : pkgDirs)
addPkg(pkgDir, priorityCounter++);
}
debug("created %d symlinks in user environment", state.symlinks);
}
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;
};
Path 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"));
auto itemIt = derivations.begin();
while (itemIt != derivations.end()) {
/* !!! We're trusting the caller to structure derivations env var correctly */
const bool active = "false" != *itemIt++;
const int priority = stoi(*itemIt++);
const size_t outputs = stoul(*itemIt++);
for (size_t n {0}; n < outputs; n++) {
pkgs.emplace_back(std::move(*itemIt++), active, priority);
}
}
}
buildProfile(out, std::move(pkgs));
createSymlink(getAttr("manifest"), out + "/manifest.nix");
}
}
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