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Merge branch 'master' into no-manifests

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This commit is contained in:
Eelco Dolstra 2012-08-27 11:09:07 -04:00
commit e94806d030
20 changed files with 325 additions and 139 deletions
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43
src/libstore/build.cc
View file

@ -45,7 +45,7 @@
#include <sched.h>
#endif
#define CHROOT_ENABLED HAVE_CHROOT && HAVE_UNSHARE && HAVE_SYS_MOUNT_H && defined(MS_BIND) && defined(CLONE_NEWNS)
#define CHROOT_ENABLED HAVE_CHROOT && HAVE_UNSHARE && HAVE_SYS_MOUNT_H && defined(MS_BIND) && defined(MS_PRIVATE) && defined(CLONE_NEWNS)
#if CHROOT_ENABLED
#include <sys/socket.h>
@ -604,18 +604,17 @@ void getOwnership(const Path & path)
}
void deletePathWrapped(const Path & path,
unsigned long long & bytesFreed, unsigned long long & blocksFreed)
void deletePathWrapped(const Path & path, unsigned long long & bytesFreed)
{
try {
/* First try to delete it ourselves. */
deletePath(path, bytesFreed, blocksFreed);
deletePath(path, bytesFreed);
} catch (SysError & e) {
/* If this failed due to a permission error, then try it with
the setuid helper. */
if (settings.buildUsersGroup != "" && !amPrivileged()) {
getOwnership(path);
deletePath(path, bytesFreed, blocksFreed);
deletePath(path, bytesFreed);
} else
throw;
}
@ -624,8 +623,8 @@ void deletePathWrapped(const Path & path,
void deletePathWrapped(const Path & path)
{
unsigned long long dummy1, dummy2;
deletePathWrapped(path, dummy1, dummy2);
unsigned long long dummy1;
deletePathWrapped(path, dummy1);
}
@ -1470,9 +1469,9 @@ HookReply DerivationGoal::tryBuildHook()
}
void chmod(const Path & path, mode_t mode)
void chmod_(const Path & path, mode_t mode)
{
if (::chmod(path.c_str(), 01777) == -1)
if (chmod(path.c_str(), mode) == -1)
throw SysError(format("setting permissions on `%1%'") % path);
}
@ -1674,7 +1673,7 @@ void DerivationGoal::startBuilder()
instead.) */
Path chrootTmpDir = chrootRootDir + "/tmp";
createDirs(chrootTmpDir);
chmod(chrootTmpDir, 01777);
chmod_(chrootTmpDir, 01777);
/* Create a /etc/passwd with entries for the build user and the
nobody account. The latter is kind of a hack to support
@ -1710,7 +1709,7 @@ void DerivationGoal::startBuilder()
precaution, make the fake Nix store only writable by the
build user. */
createDirs(chrootRootDir + settings.nixStore);
chmod(chrootRootDir + settings.nixStore, 01777);
chmod_(chrootRootDir + settings.nixStore, 01777);
foreach (PathSet::iterator, i, inputPaths) {
struct stat st;
@ -1844,22 +1843,40 @@ void DerivationGoal::initChild()
char domainname[] = "(none)"; // kernel default
setdomainname(domainname, sizeof(domainname));
/* Make all filesystems private. This is necessary
because subtrees may have been mounted as "shared"
(MS_SHARED). (Systemd does this, for instance.) Even
though we have a private mount namespace, mounting
filesystems on top of a shared subtree still propagates
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");
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);
}
/* Bind-mount all the directories from the "host"
filesystem that we want in the chroot
environment. */
foreach (PathSet::iterator, i, dirsInChroot) {
Path source = *i;
Path target = chrootRootDir + source;
if (source == "/proc") continue; // backwards compatibility
debug(format("bind mounting `%1%' to `%2%'") % source % target);
createDirs(target);
if (mount(source.c_str(), target.c_str(), "", MS_BIND, 0) == -1)
throw SysError(format("bind mount from `%1%' to `%2%' failed") % source % target);
}
/* Bind a new instance of procfs on /proc to reflect our
private PID namespace. */
createDirs(chrootRootDir + "/proc");
if (mount("none", (chrootRootDir + "/proc").c_str(), "proc", 0, 0) == -1)
throw SysError("mounting /proc");

32
src/libstore/gc.cc
View file

@ -425,10 +425,9 @@ bool LocalStore::isActiveTempFile(const GCState & state,
void LocalStore::deleteGarbage(GCState & state, const Path & path)
{
printMsg(lvlInfo, format("deleting `%1%'") % path);
unsigned long long bytesFreed, blocksFreed;
deletePathWrapped(path, bytesFreed, blocksFreed);
unsigned long long bytesFreed;
deletePathWrapped(path, bytesFreed);
state.results.bytesFreed += bytesFreed;
state.results.blocksFreed += blocksFreed;
}
@ -550,7 +549,7 @@ bool LocalStore::tryToDelete(GCState & state, const Path & path)
} else
deleteGarbage(state, path);
if (state.options.maxFreed && state.results.bytesFreed + state.bytesInvalidated > state.options.maxFreed) {
if (state.results.bytesFreed + state.bytesInvalidated > state.options.maxFreed) {
printMsg(lvlInfo, format("deleted or invalidated more than %1% bytes; stopping") % state.options.maxFreed);
throw GCLimitReached();
}
@ -576,11 +575,13 @@ bool LocalStore::tryToDelete(GCState & state, const Path & path)
safely deleted. FIXME: race condition with optimisePath(): we
might see a link count of 1 just before optimisePath() increases
the link count. */
void LocalStore::removeUnusedLinks()
void LocalStore::removeUnusedLinks(const GCState & state)
{
AutoCloseDir dir = opendir(linksDir.c_str());
if (!dir) throw SysError(format("opening directory `%1%'") % linksDir);
long long actualSize = 0, unsharedSize = 0;
struct dirent * dirent;
while (errno = 0, dirent = readdir(dir)) {
checkInterrupt();
@ -592,13 +593,28 @@ void LocalStore::removeUnusedLinks()
if (lstat(path.c_str(), &st) == -1)
throw SysError(format("statting `%1%'") % path);
if (st.st_nlink != 1) continue;
if (st.st_nlink != 1) {
unsigned long long size = st.st_blocks * 512ULL;
actualSize += size;
unsharedSize += (st.st_nlink - 1) * size;
continue;
}
printMsg(lvlTalkative, format("deleting unused link `%1%'") % path);
if (unlink(path.c_str()) == -1)
throw SysError(format("deleting `%1%'") % path);
state.results.bytesFreed += st.st_blocks * 512;
}
struct stat st;
if (stat(linksDir.c_str(), &st) == -1)
throw SysError(format("statting `%1%'") % linksDir);
long long overhead = st.st_blocks * 512ULL;
printMsg(lvlInfo, format("note: currently hard linking saves %.2f MiB")
% ((unsharedSize - actualSize - overhead) / (1024.0 * 1024.0)));
}
@ -660,7 +676,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
throw Error(format("cannot delete path `%1%' since it is still alive") % *i);
}
} else {
} else if (options.maxFreed > 0) {
if (shouldDelete(state.options.action))
printMsg(lvlError, format("deleting garbage..."));
@ -718,7 +734,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
/* Clean up the links directory. */
printMsg(lvlError, format("deleting unused links..."));
removeUnusedLinks();
removeUnusedLinks(state);
}

5
src/libstore/local-store.hh
View file

@ -261,7 +261,7 @@ private:
int openGCLock(LockType lockType);
void removeUnusedLinks();
void removeUnusedLinks(const GCState & state);
void startSubstituter(const Path & substituter,
RunningSubstituter & runningSubstituter);
@ -298,8 +298,7 @@ void getOwnership(const Path & path);
/* Like deletePath(), but changes the ownership of `path' using the
setuid wrapper if necessary (and possible). */
void deletePathWrapped(const Path & path,
unsigned long long & bytesFreed, unsigned long long & blocksFreed);
void deletePathWrapped(const Path & path, unsigned long long & bytesFreed);
void deletePathWrapped(const Path & path);

74
src/libstore/optimise-store.cc
View file

@ -102,11 +102,11 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
/* Nope, create a hard link in the links directory. */
makeMutable(path);
MakeImmutable mk1(path);
if (link(path.c_str(), linkPath.c_str()) == -1)
if (link(path.c_str(), linkPath.c_str()) == 0) return;
if (errno != EEXIST)
throw SysError(format("cannot link `%1%' to `%2%'") % linkPath % path);
return;
/* Fall through if another process created ‘linkPath’ before
we did. */
}
/* Yes! We've seen a file with the same contents. Replace the
@ -123,9 +123,6 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
printMsg(lvlTalkative, format("linking `%1%' to `%2%'") % path % linkPath);
Path tempLink = (format("%1%/.tmp-link-%2%-%3%")
% settings.nixStore % getpid() % rand()).str();
/* Make the containing directory writable, but only if it's not
the store itself (we don't want or need to mess with its
permissions). */
@ -140,40 +137,55 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path)
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. */
makeMutable(linkPath);
MakeImmutable mk1(linkPath);
makeMutable(path);
MakeImmutable mk2(path);
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. */
printMsg(lvlInfo, format("`%1%' has maximum number of links") % linkPath);
return;
/* 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();
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);
}
throw SysError(format("cannot link `%1%' to `%2%'") % tempLink % linkPath);
}
/* Atomically replace the old file with the new hard link. */
if (rename(tempLink.c_str(), path.c_str()) == -1) {
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.) */
printMsg(lvlInfo, format("`%1%' has maximum number of links") % linkPath);
/* Unlink the temp link. */
/* 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);
return;
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);
}
throw SysError(format("cannot rename `%1%' to `%2%'") % tempLink % path);
break;
}
if (retries == 0) throw Error(format("cannot link `%1%' to `%2%'") % path % linkPath);
stats.filesLinked++;
stats.bytesFreed += st.st_size;
stats.blocksFreed += st.st_blocks;

2
src/libstore/remote-store.cc
View file

@ -558,7 +558,7 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
results.paths = readStrings<PathSet>(from);
results.bytesFreed = readLongLong(from);
results.blocksFreed = readLongLong(from);
readLongLong(from); // obsolete
}

4
src/libstore/store-api.cc
View file

@ -2,7 +2,7 @@
#include "globals.hh"
#include "util.hh"
#include <limits.h>
#include <climits>
namespace nix {
@ -12,7 +12,7 @@ GCOptions::GCOptions()
{
action = gcDeleteDead;
ignoreLiveness = false;
maxFreed = 0;
maxFreed = ULLONG_MAX;
}

7
src/libstore/store-api.hh
View file

@ -48,8 +48,7 @@ struct GCOptions
/* For `gcDeleteSpecific', the paths to delete. */
PathSet pathsToDelete;
/* Stop after at least `maxFreed' bytes have been freed. 0 means
no limit. */
/* Stop after at least `maxFreed' bytes have been freed. */
unsigned long long maxFreed;
GCOptions();
@ -66,13 +65,9 @@ struct GCResults
number of bytes that would be or was freed. */
unsigned long long bytesFreed;
/* The number of file system blocks that would be or was freed. */
unsigned long long blocksFreed;
GCResults()
{
bytesFreed = 0;
blocksFreed = 0;
}
};