nix-super/src/libstore/builtins/buildenv.cc

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#include "builtins.hh"
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#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <algorithm>
namespace nix {
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typedef std::map<Path,int> Priorities;
// FIXME: change into local variables.
static Priorities priorities;
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static unsigned long symlinks;
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/* 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;
}
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for (const auto & ent : srcFiles) {
if (ent.name[0] == '.')
/* not matched by glob */
continue;
auto srcFile = srcDir + "/" + ent.name;
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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;
}
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/* 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"))
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continue;
else if (S_ISDIR(srcSt.st_mode)) {
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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);
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if (unlink(dstFile.c_str()) == -1)
throw SysError(format("unlinking '%1%'") % dstFile);
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if (mkdir(dstFile.c_str(), 0755) == -1)
throw SysError(format("creating directory '%1%'"));
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createLinks(target, dstFile, priorities[dstFile]);
createLinks(srcFile, dstFile, priority);
continue;
}
} else if (errno != ENOENT)
throw SysError(format("getting status of '%1%'") % dstFile);
}
else {
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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(
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"packages '%1%' and '%2%' have the same priority %3%; "
"use 'nix-env --set-flag priority NUMBER INSTALLED_PKGNAME' "
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"to change the priority of one of the conflicting packages"
" (0 being the highest priority)",
srcFile, readLink(dstFile), priority);
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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);
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} else if (errno != ENOENT)
throw SysError(format("getting status of '%1%'") % dstFile);
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}
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createSymlink(srcFile, dstFile);
priorities[dstFile] = priority;
symlinks++;
}
}
typedef std::set<Path> FileProp;
static FileProp done;
static FileProp postponed = FileProp{};
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static Path out;
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static void addPkg(const Path & pkgDir, int priority)
{
if (!done.insert(pkgDir).second) return;
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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;
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}
}
struct Package {
Path path;
bool active;
int priority;
Package(Path path, bool active, int priority) : path{path}, active{active}, priority{priority} {}
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};
typedef std::vector<Package> Packages;
void builtinBuildenv(const BasicDerivation & drv)
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{
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);
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}
}
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/* 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++);
}
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printError("created %d symlinks in user environment", symlinks);
createSymlink(getAttr("manifest"), out + "/manifest.nix");
}
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}