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Merge branch 'readonly-store'

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This commit is contained in:
Eelco Dolstra 2012-09-25 15:38:00 -04:00
commit e464b0247d
14 changed files with 105 additions and 134 deletions
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32
src/libstore/build.cc
View file

@ -1355,11 +1355,6 @@ void DerivationGoal::buildDone()
/* Delete the chroot (if we were using one). */
autoDelChroot.reset(); /* this runs the destructor */
/* Deleting the chroot will have caused the immutable bits on
hard-linked inputs to be cleared. So set them again. */
foreach (PathSet::iterator, i, regularInputPaths)
makeImmutable(*i);
/* Delete redirected outputs (when doing hash rewriting). */
foreach (PathSet::iterator, i, redirectedOutputs)
deletePath(*i);
@ -1435,7 +1430,7 @@ HookReply DerivationGoal::tryBuildHook()
/* Tell the hook about system features (beyond the system type)
required from the build machine. (The hook could parse the
drv file itself, but this is easier.) */
Strings features = tokenizeString(drv.env["requiredSystemFeatures"]);
Strings features = tokenizeString<Strings>(drv.env["requiredSystemFeatures"]);
foreach (Strings::iterator, i, features) checkStoreName(*i); /* !!! abuse */
/* Send the request to the hook. */
@ -1594,7 +1589,7 @@ void DerivationGoal::startBuilder()
fixed-output derivations is by definition pure (since we
already know the cryptographic hash of the output). */
if (fixedOutput) {
Strings varNames = tokenizeString(drv.env["impureEnvVars"]);
Strings varNames = tokenizeString<Strings>(drv.env["impureEnvVars"]);
foreach (Strings::iterator, i, varNames) env[*i] = getEnv(*i);
}
@ -1606,7 +1601,7 @@ void DerivationGoal::startBuilder()
by `nix-store --register-validity'. However, the deriver
fields are left empty. */
string s = drv.env["exportReferencesGraph"];
Strings ss = tokenizeString(s);
Strings ss = tokenizeString<Strings>(s);
if (ss.size() % 2 != 0)
throw BuildError(format("odd number of tokens in `exportReferencesGraph': `%1%'") % s);
for (Strings::iterator i = ss.begin(); i != ss.end(); ) {
@ -1766,11 +1761,8 @@ void DerivationGoal::startBuilder()
/* Hard-linking fails if we exceed the maximum
link count on a file (e.g. 32000 of ext3),
which is quite possible after a `nix-store
--optimise'. It can also fail if another
process called makeImmutable() on *i after we
did makeMutable(). In those cases, make a copy
instead. */
if (errno != EMLINK && errno != EPERM)
--optimise'. */
if (errno != EMLINK)
throw SysError(format("linking `%1%' to `%2%'") % p % *i);
StringSink sink;
dumpPath(*i, sink);
@ -1778,7 +1770,6 @@ void DerivationGoal::startBuilder()
restorePath(p, source);
}
makeImmutable(*i);
regularInputPaths.insert(*i);
}
}
@ -1911,14 +1902,11 @@ void DerivationGoal::initChild()
outside of the namespace. Making a subtree private is
local to the namespace, though, so setting MS_PRIVATE
does not affect the outside world. */
Strings mounts = tokenizeString(readFile("/proc/self/mountinfo", true), "\n");
Strings mounts = tokenizeString<Strings>(readFile("/proc/self/mountinfo", true), "\n");
foreach (Strings::iterator, i, mounts) {
Strings fields = tokenizeString(*i, " ");
assert(fields.size() >= 5);
Strings::iterator j = fields.begin();
std::advance(j, 4);
if (mount(0, j->c_str(), 0, MS_PRIVATE, 0) == -1)
throw SysError(format("unable to make filesystem `%1%' private") % *j);
vector<string> fields = tokenizeString<vector<string> >(*i, " ");
if (mount(0, fields.at(4).c_str(), 0, MS_PRIVATE, 0) == -1)
throw SysError(format("unable to make filesystem `%1%' private") % fields.at(4));
}
/* Bind-mount all the directories from the "host"
@ -2053,7 +2041,7 @@ void DerivationGoal::initChild()
PathSet parseReferenceSpecifiers(const Derivation & drv, string attr)
{
PathSet result;
Paths paths = tokenizeString(attr);
Paths paths = tokenizeString<Paths>(attr);
foreach (Strings::iterator, i, paths) {
if (isStorePath(*i))
result.insert(*i);

2
src/libstore/gc.cc
View file

@ -373,7 +373,7 @@ static void addAdditionalRoots(StoreAPI & store, PathSet & roots)
string result = runProgram(rootFinder);
Strings paths = tokenizeString(result, "\n");
Strings paths = tokenizeString<Strings>(result, "\n");
foreach (Strings::iterator, i, paths) {
if (isInStore(*i)) {

20
src/libstore/globals.cc
View file

@ -65,15 +65,7 @@ void Settings::processEnvironment()
substituters.push_back(nixLibexecDir + "/nix/substituters/download-using-manifests.pl");
substituters.push_back(nixLibexecDir + "/nix/substituters/download-from-binary-cache.pl");
} else
substituters = tokenizeString(subs, ":");
}
string & at(Strings & ss, unsigned int n)
{
Strings::iterator i = ss.begin();
advance(i, n);
return *i;
substituters = tokenizeString<Strings>(subs, ":");
}
@ -95,15 +87,15 @@ void Settings::loadConfFile()
if (hash != string::npos)
line = string(line, 0, hash);
Strings tokens = tokenizeString(line);
vector<string> tokens = tokenizeString<vector<string> >(line);
if (tokens.empty()) continue;
if (tokens.size() < 2 || at(tokens, 1) != "=")
if (tokens.size() < 2 || tokens[1] != "=")
throw Error(format("illegal configuration line `%1%' in `%2%'") % line % settingsFile);
string name = at(tokens, 0);
string name = tokens[0];
Strings::iterator i = tokens.begin();
vector<string>::iterator i = tokens.begin();
advance(i, 2);
settings[name] = concatStringsSep(" ", Strings(i, tokens.end())); // FIXME: slow
};
@ -170,7 +162,7 @@ void Settings::get(PathSet & res, const string & name)
SettingsMap::iterator i = settings.find(name);
if (i == settings.end()) return;
res.clear();
Strings ss = tokenizeString(i->second);
Strings ss = tokenizeString<Strings>(i->second);
res.insert(ss.begin(), ss.end());
}

47
src/libstore/local-store.cc
View file

@ -20,6 +20,11 @@
#include <stdio.h>
#include <time.h>
#if HAVE_UNSHARE
#include <sched.h>
#include <sys/mount.h>
#endif
#include <sqlite3.h>
@ -292,6 +297,8 @@ LocalStore::LocalStore(bool reserveSpace)
}
else openDB(false);
makeStoreWritable();
}
@ -411,6 +418,38 @@ void LocalStore::openDB(bool create)
}
/* To improve purity, users may want to make the Nix store a read-only
bind mount. So make the Nix store writable for this process. */
void LocalStore::makeStoreWritable()
{
#if HAVE_UNSHARE
if (getuid() != 0) return;
if (!pathExists("/proc/self/mountinfo")) return;
/* Check if /nix/store is a read-only bind mount. */
bool found = false;
Strings mounts = tokenizeString<Strings>(readFile("/proc/self/mountinfo", true), "\n");
foreach (Strings::iterator, i, mounts) {
vector<string> fields = tokenizeString<vector<string> >(*i, " ");
if (fields.at(3) == "/" || fields.at(4) != settings.nixStore) continue;
Strings options = tokenizeString<Strings>(fields.at(5), ",");
if (std::find(options.begin(), options.end(), "ro") == options.end()) continue;
found = true;
break;
}
if (!found) return;
if (unshare(CLONE_NEWNS) == -1)
throw SysError("setting up a private mount namespace");
if (mount(0, settings.nixStore.c_str(), 0, MS_REMOUNT | MS_BIND, 0) == -1)
throw SysError(format("remounting %1% writable") % settings.nixStore);
#endif
}
const time_t mtimeStore = 1; /* 1 second into the epoch */
@ -478,8 +517,6 @@ void canonicalisePathMetaData(const Path & path, bool recurse)
foreach (Strings::iterator, i, names)
canonicalisePathMetaData(path + "/" + *i, true);
}
makeImmutable(path);
}
@ -1435,7 +1472,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
/* Lock the output path. But don't lock if we're being called
from a build hook (whose parent process already acquired a
lock on this path). */
Strings locksHeld = tokenizeString(getEnv("NIX_HELD_LOCKS"));
Strings locksHeld = tokenizeString<Strings>(getEnv("NIX_HELD_LOCKS"));
if (find(locksHeld.begin(), locksHeld.end(), dstPath) == locksHeld.end())
outputLock.lockPaths(singleton<PathSet, Path>(dstPath));
@ -1645,7 +1682,7 @@ ValidPathInfo LocalStore::queryPathInfoOld(const Path & path)
string info = readFile(infoFile);
/* Parse it. */
Strings lines = tokenizeString(info, "\n");
Strings lines = tokenizeString<Strings>(info, "\n");
foreach (Strings::iterator, i, lines) {
string::size_type p = i->find(':');
@ -1654,7 +1691,7 @@ ValidPathInfo LocalStore::queryPathInfoOld(const Path & path)
string name(*i, 0, p);
string value(*i, p + 2);
if (name == "References") {
Strings refs = tokenizeString(value, " ");
Strings refs = tokenizeString<Strings>(value, " ");
res.references = PathSet(refs.begin(), refs.end());
} else if (name == "Deriver") {
res.deriver = value;

2
src/libstore/local-store.hh
View file

@ -228,6 +228,8 @@ private:
void openDB(bool create);
void makeStoreWritable();
unsigned long long queryValidPathId(const Path & path);
unsigned long long addValidPath(const ValidPathInfo & info, bool checkOutputs = true);

86
src/libstore/optimise-store.cc
View file

@ -33,8 +33,7 @@ struct MakeReadOnly
~MakeReadOnly()
{
try {
/* This will make the path read-only (and restore the
immutable bit on platforms that support it). */
/* This will make the path read-only. */
if (path != "") canonicalisePathMetaData(path, false);
} catch (...) {
ignoreException();
@ -43,14 +42,6 @@ struct MakeReadOnly
};
struct MakeImmutable
{
Path path;
MakeImmutable(const Path & path) : path(path) { }
~MakeImmutable() { makeImmutable(path); }
};
void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
{
checkInterrupt();
@ -101,7 +92,6 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
if (!pathExists(linkPath)) {
/* Nope, create a hard link in the links directory. */
makeMutable(path);
MakeImmutable mk1(path);
if (link(path.c_str(), linkPath.c_str()) == 0) return;
if (errno != EEXIST)
throw SysError(format("cannot link `%1%' to `%2%'") % linkPath % path);
@ -134,57 +124,41 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
MakeReadOnly makeReadOnly(mustToggle ? dirOf(path) : "");
/* If ‘linkPath’ is immutable, we can't create hard links to it,
so make it mutable first (and make it immutable again when
we're done). We also have to make ‘path’ mutable, otherwise
rename() will fail to delete it. */
so make it mutable first. We also have to make ‘path’ mutable,
otherwise rename() will fail to delete it. */
makeMutable(path);
MakeImmutable mk2(path);
makeMutable(linkPath);
/* Another process might be doing the same thing (creating a new
link to ‘linkPath’) and make ‘linkPath’ immutable before we're
done. In that case, just retry. */
unsigned int retries = 1024;
while (--retries > 0) {
makeMutable(linkPath);
MakeImmutable mk1(linkPath);
Path tempLink = (format("%1%/.tmp-link-%2%-%3%")
% settings.nixStore % getpid() % rand()).str();
Path tempLink = (format("%1%/.tmp-link-%2%-%3%")
% settings.nixStore % getpid() % rand()).str();
if (link(linkPath.c_str(), tempLink.c_str()) == -1) {
if (errno == EMLINK) {
/* Too many links to the same file (>= 32000 on most
file systems). This is likely to happen with empty
files. Just shrug and ignore. */
if (st.st_size)
printMsg(lvlInfo, format("`%1%' has maximum number of links") % linkPath);
return;
}
if (errno == EPERM) continue;
throw SysError(format("cannot link `%1%' to `%2%'") % tempLink % linkPath);
if (link(linkPath.c_str(), tempLink.c_str()) == -1) {
if (errno == EMLINK) {
/* Too many links to the same file (>= 32000 on most file
systems). This is likely to happen with empty files.
Just shrug and ignore. */
if (st.st_size)
printMsg(lvlInfo, format("`%1%' has maximum number of links") % linkPath);
return;
}
/* Atomically replace the old file with the new hard link. */
if (rename(tempLink.c_str(), path.c_str()) == -1) {
if (unlink(tempLink.c_str()) == -1)
printMsg(lvlError, format("unable to unlink `%1%'") % tempLink);
if (errno == EMLINK) {
/* Some filesystems generate too many links on the
rename, rather than on the original link.
(Probably it temporarily increases the st_nlink
field before decreasing it again.) */
if (st.st_size)
printMsg(lvlInfo, format("`%1%' has maximum number of links") % linkPath);
return;
}
if (errno == EPERM) continue;
throw SysError(format("cannot rename `%1%' to `%2%'") % tempLink % path);
}
break;
throw SysError(format("cannot link `%1%' to `%2%'") % tempLink % linkPath);
}
if (retries == 0) throw Error(format("cannot link `%1%' to `%2%'") % path % linkPath);
/* Atomically replace the old file with the new hard link. */
if (rename(tempLink.c_str(), path.c_str()) == -1) {
if (unlink(tempLink.c_str()) == -1)
printMsg(lvlError, format("unable to unlink `%1%'") % tempLink);
if (errno == EMLINK) {
/* Some filesystems generate too many links on the rename,
rather than on the original link. (Probably it
temporarily increases the st_nlink field before
decreasing it again.) */
if (st.st_size)
printMsg(lvlInfo, format("`%1%' has maximum number of links") % linkPath);
return;
}
throw SysError(format("cannot rename `%1%' to `%2%'") % tempLink % path);
}
stats.filesLinked++;
stats.bytesFreed += st.st_size;