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Diffstat (limited to 'src/libstore/build.cc')
| -rw-r--r-- | src/libstore/build.cc | 3258 |
1 files changed, 3258 insertions, 0 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc new file mode 100644 index 000000000000..1b379752fa0e --- /dev/null +++ b/src/libstore/build.cc @@ -0,0 +1,3258 @@ +#include "config.h" + +#include "references.hh" +#include "pathlocks.hh" +#include "misc.hh" +#include "globals.hh" +#include "local-store.hh" +#include "util.hh" +#include "archive.hh" +#include "affinity.hh" + +#include <map> +#include <sstream> +#include <algorithm> +#include <boost/shared_ptr.hpp> +#include <boost/weak_ptr.hpp> +#include <boost/enable_shared_from_this.hpp> + +#include <time.h> +#include <sys/time.h> +#include <sys/wait.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/utsname.h> +#include <fcntl.h> +#include <unistd.h> +#include <errno.h> +#include <stdio.h> +#include <cstring> + +#include <pwd.h> +#include <grp.h> + +#include <bzlib.h> + + +/* Includes required for chroot support. */ +#if HAVE_SYS_PARAM_H +#include <sys/param.h> +#endif +#if HAVE_SYS_MOUNT_H +#include <sys/mount.h> +#endif +#if HAVE_SCHED_H +#include <sched.h> +#endif + +/* In GNU libc 2.11, <sys/mount.h> does not define `MS_PRIVATE', but + <linux/fs.h> does. */ +#if !defined MS_PRIVATE && defined HAVE_LINUX_FS_H +#include <linux/fs.h> +#endif + +#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> +#include <sys/ioctl.h> +#include <net/if.h> +#include <netinet/ip.h> +#endif + + +#if HAVE_SYS_PERSONALITY_H +#include <sys/personality.h> +#define CAN_DO_LINUX32_BUILDS +#endif + + +namespace nix { + +using std::map; + + +static string pathNullDevice = "/dev/null"; + + +/* Forward definition. */ +class Worker; +struct HookInstance; + + +/* A pointer to a goal. */ +class Goal; +typedef boost::shared_ptr<Goal> GoalPtr; +typedef boost::weak_ptr<Goal> WeakGoalPtr; + +/* Set of goals. */ +typedef set<GoalPtr> Goals; +typedef set<WeakGoalPtr> WeakGoals; + +/* A map of paths to goals (and the other way around). */ +typedef map<Path, WeakGoalPtr> WeakGoalMap; + + + +class Goal : public boost::enable_shared_from_this<Goal> +{ +public: + typedef enum {ecBusy, ecSuccess, ecFailed, ecNoSubstituters, ecIncompleteClosure} ExitCode; + +protected: + + /* Backlink to the worker. */ + Worker & worker; + + /* Goals that this goal is waiting for. */ + Goals waitees; + + /* Goals waiting for this one to finish. Must use weak pointers + here to prevent cycles. */ + WeakGoals waiters; + + /* Number of goals we are/were waiting for that have failed. */ + unsigned int nrFailed; + + /* Number of substitution goals we are/were waiting for that + failed because there are no substituters. */ + unsigned int nrNoSubstituters; + + /* Number of substitution goals we are/were waiting for that + failed because othey had unsubstitutable references. */ + unsigned int nrIncompleteClosure; + + /* Name of this goal for debugging purposes. */ + string name; + + /* Whether the goal is finished. */ + ExitCode exitCode; + + Goal(Worker & worker) : worker(worker) + { + nrFailed = nrNoSubstituters = nrIncompleteClosure = 0; + exitCode = ecBusy; + } + + virtual ~Goal() + { + trace("goal destroyed"); + } + +public: + virtual void work() = 0; + + void addWaitee(GoalPtr waitee); + + virtual void waiteeDone(GoalPtr waitee, ExitCode result); + + virtual void handleChildOutput(int fd, const string & data) + { + abort(); + } + + virtual void handleEOF(int fd) + { + abort(); + } + + void trace(const format & f); + + string getName() + { + return name; + } + + ExitCode getExitCode() + { + return exitCode; + } + + /* Cancel the goal. It should wake up its waiters, get rid of any + running child processes that are being monitored by the worker + (important!), etc. */ + virtual void cancel(bool timeout) = 0; + +protected: + void amDone(ExitCode result); +}; + + +/* A mapping used to remember for each child process to what goal it + belongs, and file descriptors for receiving log data and output + path creation commands. */ +struct Child +{ + WeakGoalPtr goal; + set<int> fds; + bool respectTimeouts; + bool inBuildSlot; + time_t lastOutput; /* time we last got output on stdout/stderr */ + time_t timeStarted; +}; + +typedef map<pid_t, Child> Children; + + +/* The worker class. */ +class Worker +{ +private: + + /* Note: the worker should only have strong pointers to the + top-level goals. */ + + /* The top-level goals of the worker. */ + Goals topGoals; + + /* Goals that are ready to do some work. */ + WeakGoals awake; + + /* Goals waiting for a build slot. */ + WeakGoals wantingToBuild; + + /* Child processes currently running. */ + Children children; + + /* Number of build slots occupied. This includes local builds and + substitutions but not remote builds via the build hook. */ + unsigned int nrLocalBuilds; + + /* Maps used to prevent multiple instantiations of a goal for the + same derivation / path. */ + WeakGoalMap derivationGoals; + WeakGoalMap substitutionGoals; + + /* Goals waiting for busy paths to be unlocked. */ + WeakGoals waitingForAnyGoal; + + /* Goals sleeping for a few seconds (polling a lock). */ + WeakGoals waitingForAWhile; + + /* Last time the goals in `waitingForAWhile' where woken up. */ + time_t lastWokenUp; + +public: + + /* Set if at least one derivation had a BuildError (i.e. permanent + failure). */ + bool permanentFailure; + + LocalStore & store; + + boost::shared_ptr<HookInstance> hook; + + Worker(LocalStore & store); + ~Worker(); + + /* Make a goal (with caching). */ + GoalPtr makeDerivationGoal(const Path & drvPath, const StringSet & wantedOutputs, bool repair = false); + GoalPtr makeSubstitutionGoal(const Path & storePath, bool repair = false); + + /* Remove a dead goal. */ + void removeGoal(GoalPtr goal); + + /* Wake up a goal (i.e., there is something for it to do). */ + void wakeUp(GoalPtr goal); + + /* Return the number of local build and substitution processes + currently running (but not remote builds via the build + hook). */ + unsigned int getNrLocalBuilds(); + + /* Registers a running child process. `inBuildSlot' means that + the process counts towards the jobs limit. */ + void childStarted(GoalPtr goal, pid_t pid, + const set<int> & fds, bool inBuildSlot, bool respectTimeouts); + + /* Unregisters a running child process. `wakeSleepers' should be + false if there is no sense in waking up goals that are sleeping + because they can't run yet (e.g., there is no free build slot, + or the hook would still say `postpone'). */ + void childTerminated(pid_t pid, bool wakeSleepers = true); + + /* Put `goal' to sleep until a build slot becomes available (which + might be right away). */ + void waitForBuildSlot(GoalPtr goal); + + /* Wait for any goal to finish. Pretty indiscriminate way to + wait for some resource that some other goal is holding. */ + void waitForAnyGoal(GoalPtr goal); + + /* Wait for a few seconds and then retry this goal. Used when + waiting for a lock held by another process. This kind of + polling is inefficient, but POSIX doesn't really provide a way + to wait for multiple locks in the main select() loop. */ + void waitForAWhile(GoalPtr goal); + + /* Loop until the specified top-level goals have finished. */ + void run(const Goals & topGoals); + + /* Wait for input to become available. */ + void waitForInput(); + + unsigned int exitStatus(); +}; + + +////////////////////////////////////////////////////////////////////// + + +void Goal::addWaitee(GoalPtr waitee) +{ + waitees.insert(waitee); + waitee->waiters.insert(shared_from_this()); +} + + +void Goal::waiteeDone(GoalPtr waitee, ExitCode result) +{ + assert(waitees.find(waitee) != waitees.end()); + waitees.erase(waitee); + + trace(format("waitee `%1%' done; %2% left") % + waitee->name % waitees.size()); + + if (result == ecFailed || result == ecNoSubstituters || result == ecIncompleteClosure) ++nrFailed; + + if (result == ecNoSubstituters) ++nrNoSubstituters; + + if (result == ecIncompleteClosure) ++nrIncompleteClosure; + + if (waitees.empty() || (result == ecFailed && !settings.keepGoing)) { + + /* If we failed and keepGoing is not set, we remove all + remaining waitees. */ + foreach (Goals::iterator, i, waitees) { + GoalPtr goal = *i; + WeakGoals waiters2; + foreach (WeakGoals::iterator, j, goal->waiters) + if (j->lock() != shared_from_this()) waiters2.insert(*j); + goal->waiters = waiters2; + } + waitees.clear(); + + worker.wakeUp(shared_from_this()); + } +} + + +void Goal::amDone(ExitCode result) +{ + trace("done"); + assert(exitCode == ecBusy); + assert(result == ecSuccess || result == ecFailed || result == ecNoSubstituters || result == ecIncompleteClosure); + exitCode = result; + foreach (WeakGoals::iterator, i, waiters) { + GoalPtr goal = i->lock(); + if (goal) goal->waiteeDone(shared_from_this(), result); + } + waiters.clear(); + worker.removeGoal(shared_from_this()); +} + + +void Goal::trace(const format & f) +{ + debug(format("%1%: %2%") % name % f); +} + + + +////////////////////////////////////////////////////////////////////// + + +/* Common initialisation performed in child processes. */ +static void commonChildInit(Pipe & logPipe) +{ + restoreAffinity(); + + /* Put the child in a separate session (and thus a separate + process group) so that it has no controlling terminal (meaning + that e.g. ssh cannot open /dev/tty) and it doesn't receive + terminal signals. */ + if (setsid() == -1) + throw SysError(format("creating a new session")); + + /* Dup the write side of the logger pipe into stderr. */ + if (dup2(logPipe.writeSide, STDERR_FILENO) == -1) + throw SysError("cannot pipe standard error into log file"); + + /* Dup stderr to stdout. */ + if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1) + throw SysError("cannot dup stderr into stdout"); + + /* Reroute stdin to /dev/null. */ + int fdDevNull = open(pathNullDevice.c_str(), O_RDWR); + if (fdDevNull == -1) + throw SysError(format("cannot open `%1%'") % pathNullDevice); + if (dup2(fdDevNull, STDIN_FILENO) == -1) + throw SysError("cannot dup null device into stdin"); + close(fdDevNull); +} + + +/* Convert a string list to an array of char pointers. Careful: the + string list should outlive the array. */ +const char * * strings2CharPtrs(const Strings & ss) +{ + const char * * arr = new const char * [ss.size() + 1]; + const char * * p = arr; + foreach (Strings::const_iterator, i, ss) *p++ = i->c_str(); + *p = 0; + return arr; +} + + +/* Restore default handling of SIGPIPE, otherwise some programs will + randomly say "Broken pipe". */ +static void restoreSIGPIPE() +{ + struct sigaction act, oact; + act.sa_handler = SIG_DFL; + act.sa_flags = 0; + if (sigaction(SIGPIPE, &act, &oact)) throw SysError("resetting SIGPIPE"); +} + + +////////////////////////////////////////////////////////////////////// + + +class UserLock +{ +private: + /* POSIX locks suck. If we have a lock on a file, and we open and + close that file again (without closing the original file + descriptor), we lose the lock. So we have to be *very* careful + not to open a lock file on which we are holding a lock. */ + static PathSet lockedPaths; /* !!! not thread-safe */ + + Path fnUserLock; + AutoCloseFD fdUserLock; + + string user; + uid_t uid; + gid_t gid; + +public: + UserLock(); + ~UserLock(); + + void acquire(); + void release(); + + void kill(); + + string getUser() { return user; } + uid_t getUID() { return uid; } + uid_t getGID() { return gid; } + + bool enabled() { return uid != 0; } + +}; + + +PathSet UserLock::lockedPaths; + + +UserLock::UserLock() +{ + uid = gid = 0; +} + + +UserLock::~UserLock() +{ + release(); +} + + +void UserLock::acquire() +{ + assert(uid == 0); + + assert(settings.buildUsersGroup != ""); + + /* Get the members of the build-users-group. */ + struct group * gr = getgrnam(settings.buildUsersGroup.c_str()); + if (!gr) + throw Error(format("the group `%1%' specified in `build-users-group' does not exist") + % settings.buildUsersGroup); + gid = gr->gr_gid; + + /* Copy the result of getgrnam. */ + Strings users; + for (char * * p = gr->gr_mem; *p; ++p) { + debug(format("found build user `%1%'") % *p); + users.push_back(*p); + } + + if (users.empty()) + throw Error(format("the build users group `%1%' has no members") + % settings.buildUsersGroup); + + /* Find a user account that isn't currently in use for another + build. */ + foreach (Strings::iterator, i, users) { + debug(format("trying user `%1%'") % *i); + + struct passwd * pw = getpwnam(i->c_str()); + if (!pw) + throw Error(format("the user `%1%' in the group `%2%' does not exist") + % *i % settings.buildUsersGroup); + + createDirs(settings.nixStateDir + "/userpool"); + + fnUserLock = (format("%1%/userpool/%2%") % settings.nixStateDir % pw->pw_uid).str(); + + if (lockedPaths.find(fnUserLock) != lockedPaths.end()) + /* We already have a lock on this one. */ + continue; + + AutoCloseFD fd = open(fnUserLock.c_str(), O_RDWR | O_CREAT, 0600); + if (fd == -1) + throw SysError(format("opening user lock `%1%'") % fnUserLock); + closeOnExec(fd); + + if (lockFile(fd, ltWrite, false)) { + fdUserLock = fd.borrow(); + lockedPaths.insert(fnUserLock); + user = *i; + uid = pw->pw_uid; + + /* Sanity check... */ + if (uid == getuid() || uid == geteuid()) + throw Error(format("the Nix user should not be a member of `%1%'") + % settings.buildUsersGroup); + + return; + } + } + + throw Error(format("all build users are currently in use; " + "consider creating additional users and adding them to the `%1%' group") + % settings.buildUsersGroup); +} + + +void UserLock::release() +{ + if (uid == 0) return; + fdUserLock.close(); /* releases lock */ + assert(lockedPaths.find(fnUserLock) != lockedPaths.end()); + lockedPaths.erase(fnUserLock); + fnUserLock = ""; + uid = 0; +} + + +void UserLock::kill() +{ + assert(enabled()); + killUser(uid); +} + + +////////////////////////////////////////////////////////////////////// + + +struct HookInstance +{ + /* Pipes for talking to the build hook. */ + Pipe toHook; + + /* Pipe for the hook's standard output/error. */ + Pipe fromHook; + + /* Pipe for the builder's standard output/error. */ + Pipe builderOut; + + /* The process ID of the hook. */ + Pid pid; + + HookInstance(); + + ~HookInstance(); +}; + + +HookInstance::HookInstance() +{ + debug("starting build hook"); + + Path buildHook = absPath(getEnv("NIX_BUILD_HOOK")); + + /* Create a pipe to get the output of the child. */ + fromHook.create(); + + /* Create the communication pipes. */ + toHook.create(); + + /* Create a pipe to get the output of the builder. */ + builderOut.create(); + + /* Fork the hook. */ + pid = maybeVfork(); + switch (pid) { + + case -1: + throw SysError("unable to fork"); + + case 0: + try { /* child */ + + commonChildInit(fromHook); + + if (chdir("/") == -1) throw SysError("changing into `/"); + + /* Dup the communication pipes. */ + if (dup2(toHook.readSide, STDIN_FILENO) == -1) + throw SysError("dupping to-hook read side"); + + /* Use fd 4 for the builder's stdout/stderr. */ + if (dup2(builderOut.writeSide, 4) == -1) + throw SysError("dupping builder's stdout/stderr"); + + execl(buildHook.c_str(), buildHook.c_str(), settings.thisSystem.c_str(), + (format("%1%") % settings.maxSilentTime).str().c_str(), + (format("%1%") % settings.printBuildTrace).str().c_str(), + (format("%1%") % settings.buildTimeout).str().c_str(), + NULL); + + throw SysError(format("executing `%1%'") % buildHook); + + } catch (std::exception & e) { + writeToStderr("build hook error: " + string(e.what()) + "\n"); + } + _exit(1); + } + + /* parent */ + pid.setSeparatePG(true); + pid.setKillSignal(SIGTERM); + fromHook.writeSide.close(); + toHook.readSide.close(); +} + + +HookInstance::~HookInstance() +{ + try { + pid.kill(); + } catch (...) { + ignoreException(); + } +} + + +////////////////////////////////////////////////////////////////////// + + +typedef map<string, string> HashRewrites; + + +string rewriteHashes(string s, const HashRewrites & rewrites) +{ + foreach (HashRewrites::const_iterator, i, rewrites) { + assert(i->first.size() == i->second.size()); + size_t j = 0; + while ((j = s.find(i->first, j)) != string::npos) { + debug(format("rewriting @ %1%") % j); + s.replace(j, i->second.size(), i->second); + } + } + return s; +} + + +////////////////////////////////////////////////////////////////////// + + +typedef enum {rpAccept, rpDecline, rpPostpone} HookReply; + +class SubstitutionGoal; + +class DerivationGoal : public Goal +{ +private: + /* The path of the derivation. */ + Path drvPath; + + /* The specific outputs that we need to build. Empty means all of + them. */ + StringSet wantedOutputs; + + /* Whether additional wanted outputs have been added. */ + bool needRestart; + + /* Whether to retry substituting the outputs after building the + inputs. */ + bool retrySubstitution; + + /* The derivation stored at drvPath. */ + Derivation drv; + + /* The remainder is state held during the build. */ + + /* Locks on the output paths. */ + PathLocks outputLocks; + + /* All input paths (that is, the union of FS closures of the + immediate input paths). */ + PathSet inputPaths; + + /* Referenceable paths (i.e., input and output paths). */ + PathSet allPaths; + + /* Outputs that are already valid. */ + PathSet validPaths; + + /* Outputs that are corrupt or not valid. */ + PathSet missingPaths; + + /* Paths that have been subject to hash rewriting. */ + PathSet rewrittenPaths; + + /* User selected for running the builder. */ + UserLock buildUser; + + /* The process ID of the builder. */ + Pid pid; + + /* The temporary directory. */ + Path tmpDir; + + /* File descriptor for the log file. */ + FILE * fLogFile; + BZFILE * bzLogFile; + AutoCloseFD fdLogFile; + + /* Number of bytes received from the builder's stdout/stderr. */ + unsigned long logSize; + + /* Pipe for the builder's standard output/error. */ + Pipe builderOut; + + /* The build hook. */ + boost::shared_ptr<HookInstance> hook; + + /* Whether we're currently doing a chroot build. */ + bool useChroot; + + Path chrootRootDir; + + /* RAII object to delete the chroot directory. */ + boost::shared_ptr<AutoDelete> autoDelChroot; + + /* All inputs that are regular files. */ + PathSet regularInputPaths; + + /* Whether this is a fixed-output derivation. */ + bool fixedOutput; + + typedef void (DerivationGoal::*GoalState)(); + GoalState state; + + /* Stuff we need to pass to initChild(). */ + typedef map<Path, Path> DirsInChroot; // maps target path to source path + DirsInChroot dirsInChroot; + typedef map<string, string> Environment; + Environment env; + + /* Hash rewriting. */ + HashRewrites rewritesToTmp, rewritesFromTmp; + PathSet redirectedOutputs; + + /* Whether we're repairing. If set, a derivation will be rebuilt + if its outputs are valid but corrupt or missing. */ + bool repair; + map<Path, Path> redirectedBadOutputs; + + /* Set of inodes seen during calls to canonicalisePathMetaData() + for this build's outputs. This needs to be shared between + outputs to allow hard links between outputs. */ + InodesSeen inodesSeen; + + /* Magic exit code denoting that setting up the child environment + failed. (It's possible that the child actually returns the + exit code, but ah well.) */ + const static int childSetupFailed = 189; + +public: + DerivationGoal(const Path & drvPath, const StringSet & wantedOutputs, Worker & worker, bool repair = false); + ~DerivationGoal(); + + void cancel(bool timeout); + + void work(); + + Path getDrvPath() + { + return drvPath; + } + + /* Add wanted outputs to an already existing derivation goal. */ + void addWantedOutputs(const StringSet & outputs); + +private: + /* The states. */ + void init(); + void haveDerivation(); + void outputsSubstituted(); + void closureRepaired(); + void inputsRealised(); + void tryToBuild(); + void buildDone(); + + /* Is the build hook willing to perform the build? */ + HookReply tryBuildHook(); + + /* Start building a derivation. */ + void startBuilder(); + + /* Initialise the builder's process. */ + void initChild(); + + friend int childEntry(void *); + + /* Must be called after the output paths have become valid (either + due to a successful build or hook, or because they already + were). */ + void computeClosure(); + + /* Open a log file and a pipe to it. */ + Path openLogFile(); + + /* Close the log file. */ + void closeLogFile(); + + /* Delete the temporary directory, if we have one. */ + void deleteTmpDir(bool force); + + /* Callback used by the worker to write to the log. */ + void handleChildOutput(int fd, const string & data); + void handleEOF(int fd); + + /* Return the set of (in)valid paths. */ + PathSet checkPathValidity(bool returnValid, bool checkHash); + + /* Abort the goal if `path' failed to build. */ + bool pathFailed(const Path & path); + + /* Forcibly kill the child process, if any. */ + void killChild(); + + Path addHashRewrite(const Path & path); + + void repairClosure(); +}; + + +DerivationGoal::DerivationGoal(const Path & drvPath, const StringSet & wantedOutputs, Worker & worker, bool repair) + : Goal(worker) + , wantedOutputs(wantedOutputs) + , needRestart(false) + , retrySubstitution(false) + , fLogFile(0) + , bzLogFile(0) + , useChroot(false) + , repair(repair) +{ + this->drvPath = drvPath; + state = &DerivationGoal::init; + name = (format("building of `%1%'") % drvPath).str(); + trace("created"); +} + + +DerivationGoal::~DerivationGoal() +{ + /* Careful: we should never ever throw an exception from a + destructor. */ + try { + killChild(); + deleteTmpDir(false); + closeLogFile(); + } catch (...) { + ignoreException(); + } +} + + +void DerivationGoal::killChild() +{ + if (pid != -1) { + worker.childTerminated(pid); + + if (buildUser.enabled()) { + /* If we're using a build user, then there is a tricky + race condition: if we kill the build user before the + child has done its setuid() to the build user uid, then + it won't be killed, and we'll potentially lock up in + pid.wait(). So also send a conventional kill to the + child. */ + ::kill(-pid, SIGKILL); /* ignore the result */ + buildUser.kill(); + pid.wait(true); + } else + pid.kill(); + + assert(pid == -1); + } + + hook.reset(); +} + + +void DerivationGoal::cancel(bool timeout) +{ + if (settings.printBuildTrace && timeout) + printMsg(lvlError, format("@ build-failed %1% - timeout") % drvPath); + killChild(); + amDone(ecFailed); +} + + +void DerivationGoal::work() +{ + (this->*state)(); +} + + +void DerivationGoal::addWantedOutputs(const StringSet & outputs) +{ + /* If we already want all outputs, there is nothing to do. */ + if (wantedOutputs.empty()) return; + + if (outputs.empty()) { + wantedOutputs.clear(); + needRestart = true; + } else + foreach (StringSet::const_iterator, i, outputs) + if (wantedOutputs.find(*i) == wantedOutputs.end()) { + wantedOutputs.insert(*i); + needRestart = true; + } +} + + +void DerivationGoal::init() +{ + trace("init"); + + if (settings.readOnlyMode) + throw Error(format("cannot build derivation `%1%' - no write access to the Nix store") % drvPath); + + /* The first thing to do is to make sure that the derivation + exists. If it doesn't, it may be created through a + substitute. */ + addWaitee(worker.makeSubstitutionGoal(drvPath)); + + state = &DerivationGoal::haveDerivation; +} + + +void DerivationGoal::haveDerivation() +{ + trace("loading derivation"); + + if (nrFailed != 0) { + printMsg(lvlError, format("cannot build missing derivation `%1%'") % drvPath); + amDone(ecFailed); + return; + } + + /* `drvPath' should already be a root, but let's be on the safe + side: if the user forgot to make it a root, we wouldn't want + things being garbage collected while we're busy. */ + worker.store.addTempRoot(drvPath); + + assert(worker.store.isValidPath(drvPath)); + + /* Get the derivation. */ + drv = derivationFromPath(worker.store, drvPath); + + foreach (DerivationOutputs::iterator, i, drv.outputs) + worker.store.addTempRoot(i->second.path); + + /* Check what outputs paths are not already valid. */ + PathSet invalidOutputs = checkPathValidity(false, repair); + + /* If they are all valid, then we're done. */ + if (invalidOutputs.size() == 0 && !repair) { + amDone(ecSuccess); + return; + } + + /* Check whether any output previously failed to build. If so, + don't bother. */ + foreach (PathSet::iterator, i, invalidOutputs) + if (pathFailed(*i)) return; + + /* We are first going to try to create the invalid output paths + through substitutes. If that doesn't work, we'll build + them. */ + if (settings.useSubstitutes && !willBuildLocally(drv)) + foreach (PathSet::iterator, i, invalidOutputs) + addWaitee(worker.makeSubstitutionGoal(*i, repair)); + + if (waitees.empty()) /* to prevent hang (no wake-up event) */ + outputsSubstituted(); + else + state = &DerivationGoal::outputsSubstituted; +} + + +void DerivationGoal::outputsSubstituted() +{ + trace("all outputs substituted (maybe)"); + + if (nrFailed > 0 && nrFailed > nrNoSubstituters + nrIncompleteClosure && !settings.tryFallback) + throw Error(format("some substitutes for the outputs of derivation `%1%' failed (usually happens due to networking issues); try `--fallback' to build derivation from source ") % drvPath); + + /* If the substitutes form an incomplete closure, then we should + build the dependencies of this derivation, but after that, we + can still use the substitutes for this derivation itself. */ + if (nrIncompleteClosure > 0 && !retrySubstitution) retrySubstitution = true; + + nrFailed = nrNoSubstituters = nrIncompleteClosure = 0; + + if (needRestart) { + needRestart = false; + haveDerivation(); + return; + } + + if (checkPathValidity(false, repair).size() == 0) { + if (repair) repairClosure(); else amDone(ecSuccess); + return; + } + + /* Otherwise, at least one of the output paths could not be + produced using a substitute. So we have to build instead. */ + + /* Make sure checkPathValidity() from now on checks all + outputs. */ + wantedOutputs = PathSet(); + + /* The inputs must be built before we can build this goal. */ + foreach (DerivationInputs::iterator, i, drv.inputDrvs) + addWaitee(worker.makeDerivationGoal(i->first, i->second, repair)); + + foreach (PathSet::iterator, i, drv.inputSrcs) + addWaitee(worker.makeSubstitutionGoal(*i)); + + if (waitees.empty()) /* to prevent hang (no wake-up event) */ + inputsRealised(); + else + state = &DerivationGoal::inputsRealised; +} + + +void DerivationGoal::repairClosure() +{ + /* If we're repairing, we now know that our own outputs are valid. + Now check whether the other paths in the outputs closure are + good. If not, then start derivation goals for the derivations + that produced those outputs. */ + + /* Get the output closure. */ + PathSet outputClosure; + foreach (DerivationOutputs::iterator, i, drv.outputs) + computeFSClosure(worker.store, i->second.path, outputClosure); + + /* Filter out our own outputs (which we have already checked). */ + foreach (DerivationOutputs::iterator, i, drv.outputs) + outputClosure.erase(i->second.path); + + /* Get all dependencies of this derivation so that we know which + derivation is responsible for which path in the output + closure. */ + PathSet inputClosure; + computeFSClosure(worker.store, drvPath, inputClosure); + std::map<Path, Path> outputsToDrv; + foreach (PathSet::iterator, i, inputClosure) + if (isDerivation(*i)) { + Derivation drv = derivationFromPath(worker.store, *i); + foreach (DerivationOutputs::iterator, j, drv.outputs) + outputsToDrv[j->second.path] = *i; + } + + /* Check each path (slow!). */ + PathSet broken; + foreach (PathSet::iterator, i, outputClosure) { + if (worker.store.pathContentsGood(*i)) continue; + printMsg(lvlError, format("found corrupted or missing path `%1%' in the output closure of `%2%'") % *i % drvPath); + Path drvPath2 = outputsToDrv[*i]; + if (drvPath2 == "") + addWaitee(worker.makeSubstitutionGoal(*i, true)); + else + addWaitee(worker.makeDerivationGoal(drvPath2, PathSet(), true)); + } + + if (waitees.empty()) { + amDone(ecSuccess); + return; + } + + state = &DerivationGoal::closureRepaired; +} + + +void DerivationGoal::closureRepaired() +{ + trace("closure repaired"); + if (nrFailed > 0) + throw Error(format("some paths in the output closure of derivation `%1%' could not be repaired") % drvPath); + amDone(ecSuccess); +} + + +void DerivationGoal::inputsRealised() +{ + trace("all inputs realised"); + + if (nrFailed != 0) { + printMsg(lvlError, + format("cannot build derivation `%1%': " + "%2% dependencies couldn't be built") + % drvPath % nrFailed); + amDone(ecFailed); + return; + } + + if (retrySubstitution) { + haveDerivation(); + return; + } + + /* Gather information necessary for computing the closure and/or + running the build hook. */ + + /* The outputs are referenceable paths. */ + foreach (DerivationOutputs::iterator, i, drv.outputs) { + debug(format("building path `%1%'") % i->second.path); + allPaths.insert(i->second.path); + } + + /* Determine the full set of input paths. */ + + /* First, the input derivations. */ + foreach (DerivationInputs::iterator, i, drv.inputDrvs) { + /* Add the relevant output closures of the input derivation + `*i' as input paths. Only add the closures of output paths + that are specified as inputs. */ + assert(worker.store.isValidPath(i->first)); + Derivation inDrv = derivationFromPath(worker.store, i->first); + foreach (StringSet::iterator, j, i->second) + if (inDrv.outputs.find(*j) != inDrv.outputs.end()) + computeFSClosure(worker.store, inDrv.outputs[*j].path, inputPaths); + else + throw Error( + format("derivation `%1%' requires non-existent output `%2%' from input derivation `%3%'") + % drvPath % *j % i->first); + } + + /* Second, the input sources. */ + foreach (PathSet::iterator, i, drv.inputSrcs) + computeFSClosure(worker.store, *i, inputPaths); + + debug(format("added input paths %1%") % showPaths(inputPaths)); + + allPaths.insert(inputPaths.begin(), inputPaths.end()); + + /* Is this a fixed-output derivation? */ + fixedOutput = true; + foreach (DerivationOutputs::iterator, i, drv.outputs) + if (i->second.hash == "") fixedOutput = false; + + /* Okay, try to build. Note that here we don't wait for a build + slot to become available, since we don't need one if there is a + build hook. */ + state = &DerivationGoal::tryToBuild; + worker.wakeUp(shared_from_this()); +} + + +PathSet outputPaths(const DerivationOutputs & outputs) +{ + PathSet paths; + foreach (DerivationOutputs::const_iterator, i, outputs) + paths.insert(i->second.path); + return paths; +} + + +static string get(const StringPairs & map, const string & key) +{ + StringPairs::const_iterator i = map.find(key); + return i == map.end() ? (string) "" : i->second; +} + + +static bool canBuildLocally(const string & platform) +{ + return platform == settings.thisSystem +#ifdef CAN_DO_LINUX32_BUILDS + || (platform == "i686-linux" && settings.thisSystem == "x86_64-linux") +#endif + ; +} + + +bool willBuildLocally(const Derivation & drv) +{ + return get(drv.env, "preferLocalBuild") == "1" && canBuildLocally(drv.platform); +} + + +void DerivationGoal::tryToBuild() +{ + trace("trying to build"); + + /* Check for the possibility that some other goal in this process + has locked the output since we checked in haveDerivation(). + (It can't happen between here and the lockPaths() call below + because we're not allowing multi-threading.) If so, put this + goal to sleep until another goal finishes, then try again. */ + foreach (DerivationOutputs::iterator, i, drv.outputs) + if (pathIsLockedByMe(i->second.path)) { + debug(format("putting derivation `%1%' to sleep because `%2%' is locked by another goal") + % drvPath % i->second.path); + worker.waitForAnyGoal(shared_from_this()); + return; + } + + /* Obtain locks on all output paths. The locks are automatically + released when we exit this function or Nix crashes. If we + can't acquire the lock, then continue; hopefully some other + goal can start a build, and if not, the main loop will sleep a + few seconds and then retry this goal. */ + if (!outputLocks.lockPaths(outputPaths(drv.outputs), "", false)) { + worker.waitForAWhile(shared_from_this()); + return; + } + + /* Now check again whether the outputs are valid. This is because + another process may have started building in parallel. After + it has finished and released the locks, we can (and should) + reuse its results. (Strictly speaking the first check can be + omitted, but that would be less efficient.) Note that since we + now hold the locks on the output paths, no other process can + build this derivation, so no further checks are necessary. */ + validPaths = checkPathValidity(true, repair); + if (validPaths.size() == drv.outputs.size()) { + debug(format("skipping build of derivation `%1%', someone beat us to it") + % drvPath); + outputLocks.setDeletion(true); + amDone(ecSuccess); + return; + } + + missingPaths = outputPaths(drv.outputs); + foreach (PathSet::iterator, i, validPaths) missingPaths.erase(*i); + + /* If any of the outputs already exist but are not valid, delete + them. */ + foreach (DerivationOutputs::iterator, i, drv.outputs) { + Path path = i->second.path; + if (worker.store.isValidPath(path)) continue; + if (!pathExists(path)) continue; + debug(format("removing unregistered path `%1%'") % path); + deletePath(path); + } + + /* Check again whether any output previously failed to build, + because some other process may have tried and failed before we + acquired the lock. */ + foreach (DerivationOutputs::iterator, i, drv.outputs) + if (pathFailed(i->second.path)) return; + + /* Don't do a remote build if the derivation has the attribute + `preferLocalBuild' set. */ + bool buildLocally = willBuildLocally(drv); + + /* Is the build hook willing to accept this job? */ + if (!buildLocally) { + switch (tryBuildHook()) { + case rpAccept: + /* Yes, it has started doing so. Wait until we get + EOF from the hook. */ + state = &DerivationGoal::buildDone; + return; + case rpPostpone: + /* Not now; wait until at least one child finishes or + the wake-up timeout expires. */ + worker.waitForAWhile(shared_from_this()); + outputLocks.unlock(); + return; + case rpDecline: + /* We should do it ourselves. */ + break; + } + } + + /* Make sure that we are allowed to start a build. If this + derivation prefers to be done locally, do it even if + maxBuildJobs is 0. */ + unsigned int curBuilds = worker.getNrLocalBuilds(); + if (curBuilds >= settings.maxBuildJobs && !(buildLocally && curBuilds == 0)) { + worker.waitForBuildSlot(shared_from_this()); + outputLocks.unlock(); + return; + } + + try { + + /* Okay, we have to build. */ + startBuilder(); + + } catch (BuildError & e) { + printMsg(lvlError, e.msg()); + outputLocks.unlock(); + buildUser.release(); + if (settings.printBuildTrace) + printMsg(lvlError, format("@ build-failed %1% - %2% %3%") + % drvPath % 0 % e.msg()); + worker.permanentFailure = true; + amDone(ecFailed); + return; + } + + /* This state will be reached when we get EOF on the child's + log pipe. */ + state = &DerivationGoal::buildDone; +} + + +void replaceValidPath(const Path & storePath, const Path tmpPath) +{ + /* We can't atomically replace storePath (the original) with + tmpPath (the replacement), so we have to move it out of the + way first. We'd better not be interrupted here, because if + we're repairing (say) Glibc, we end up with a broken system. */ + Path oldPath = (format("%1%.old-%2%-%3%") % storePath % getpid() % rand()).str(); + if (pathExists(storePath)) + rename(storePath.c_str(), oldPath.c_str()); + if (rename(tmpPath.c_str(), storePath.c_str()) == -1) + throw SysError(format("moving `%1%' to `%2%'") % tmpPath % storePath); + if (pathExists(oldPath)) + deletePath(oldPath); +} + + +void DerivationGoal::buildDone() +{ + trace("build done"); + + /* Since we got an EOF on the logger pipe, the builder is presumed + to have terminated. In fact, the builder could also have + simply have closed its end of the pipe --- just don't do that + :-) */ + int status; + pid_t savedPid; + if (hook) { + savedPid = hook->pid; + status = hook->pid.wait(true); + } else { + /* !!! this could block! security problem! solution: kill the + child */ + savedPid = pid; + status = pid.wait(true); + } + + debug(format("builder process for `%1%' finished") % drvPath); + + /* So the child is gone now. */ + worker.childTerminated(savedPid); + + /* Close the read side of the logger pipe. */ + if (hook) { + hook->builderOut.readSide.close(); + hook->fromHook.readSide.close(); + } + else builderOut.readSide.close(); + + /* Close the log file. */ + closeLogFile(); + + /* When running under a build user, make sure that all processes + running under that uid are gone. This is to prevent a + malicious user from leaving behind a process that keeps files + open and modifies them after they have been chown'ed to + root. */ + if (buildUser.enabled()) buildUser.kill(); + + try { + + /* Some cleanup per path. We do this here and not in + computeClosure() for convenience when the build has + failed. */ + foreach (PathSet::iterator, i, missingPaths) { + Path path = *i; + + /* If the output was already valid, just skip (discard) it. */ + if (validPaths.find(path) != validPaths.end()) continue; + + if (useChroot && pathExists(chrootRootDir + path)) { + /* Move output paths from the chroot to the Nix store. */ + if (repair) + replaceValidPath(path, chrootRootDir + path); + else + if (rename((chrootRootDir + path).c_str(), path.c_str()) == -1) + throw SysError(format("moving build output `%1%' from the chroot to the Nix store") % path); + } + + Path redirected; + if (repair && (redirected = redirectedBadOutputs[path]) != "" && pathExists(redirected)) + replaceValidPath(path, redirected); + + if (!pathExists(path)) continue; + + struct stat st; + if (lstat(path.c_str(), &st) == -1) + throw SysError(format("getting attributes of path `%1%'") % path); + +#ifndef __CYGWIN__ + /* Check that the output is not group or world writable, + as that means that someone else can have interfered + with the build. Also, the output should be owned by + the build user. */ + if ((!S_ISLNK(st.st_mode) && (st.st_mode & (S_IWGRP | S_IWOTH))) || + (buildUser.enabled() && st.st_uid != buildUser.getUID())) + throw BuildError(format("suspicious ownership or permission on `%1%'; rejecting this build output") % path); +#endif + + /* Apply hash rewriting if necessary. */ + if (!rewritesFromTmp.empty()) { + printMsg(lvlError, format("warning: rewriting hashes in `%1%'; cross fingers") % path); + + /* Canonicalise first. This ensures that the path + we're rewriting doesn't contain a hard link to + /etc/shadow or something like that. */ + canonicalisePathMetaData(path, buildUser.enabled() ? buildUser.getUID() : -1, inodesSeen); + + /* FIXME: this is in-memory. */ + StringSink sink; + dumpPath(path, sink); + deletePath(path); + sink.s = rewriteHashes(sink.s, rewritesFromTmp); + StringSource source(sink.s); + restorePath(path, source); + + rewrittenPaths.insert(path); + } + } + + /* Check the exit status. */ + if (!statusOk(status)) { + deleteTmpDir(false); + if (WIFEXITED(status) && WEXITSTATUS(status) == childSetupFailed) + throw Error(format("failed to set up the build environment for `%1%'") % drvPath); + throw BuildError(format("builder for `%1%' %2%") + % drvPath % statusToString(status)); + } + + /* Delete the chroot (if we were using one). */ + autoDelChroot.reset(); /* this runs the destructor */ + + /* Delete redirected outputs (when doing hash rewriting). */ + foreach (PathSet::iterator, i, redirectedOutputs) + deletePath(*i); + + /* Compute the FS closure of the outputs and register them as + being valid. */ + computeClosure(); + + deleteTmpDir(true); + + /* It is now safe to delete the lock files, since all future + lockers will see that the output paths are valid; they will + not create new lock files with the same names as the old + (unlinked) lock files. */ + outputLocks.setDeletion(true); + outputLocks.unlock(); + + } catch (BuildError & e) { + printMsg(lvlError, e.msg()); + outputLocks.unlock(); + buildUser.release(); + + /* When using a build hook, the hook will return a remote + build failure using exit code 100. Anything else is a hook + problem. */ + bool hookError = hook && + (!WIFEXITED(status) || WEXITSTATUS(status) != 100); + + if (settings.printBuildTrace) { + if (hook && hookError) + printMsg(lvlError, format("@ hook-failed %1% - %2% %3%") + % drvPath % status % e.msg()); + else + printMsg(lvlError, format("@ build-failed %1% - %2% %3%") + % drvPath % 1 % e.msg()); + } + + /* Register the outputs of this build as "failed" so we won't + try to build them again (negative caching). However, don't + do this for fixed-output derivations, since they're likely + to fail for transient reasons (e.g., fetchurl not being + able to access the network). Hook errors (like + communication problems with the remote machine) shouldn't + be cached either. */ + if (settings.cacheFailure && !hookError && !fixedOutput) + foreach (DerivationOutputs::iterator, i, drv.outputs) + worker.store.registerFailedPath(i->second.path); + + worker.permanentFailure = !hookError && !fixedOutput; + amDone(ecFailed); + return; + } + + /* Release the build user, if applicable. */ + buildUser.release(); + + if (settings.printBuildTrace) + printMsg(lvlError, format("@ build-succeeded %1% -") % drvPath); + + amDone(ecSuccess); +} + + +HookReply DerivationGoal::tryBuildHook() +{ + if (!settings.useBuildHook || getEnv("NIX_BUILD_HOOK") == "") return rpDecline; + + if (!worker.hook) + worker.hook = boost::shared_ptr<HookInstance>(new HookInstance); + + /* 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<Strings>(get(drv.env, "requiredSystemFeatures")); + foreach (Strings::iterator, i, features) checkStoreName(*i); /* !!! abuse */ + + /* Send the request to the hook. */ + writeLine(worker.hook->toHook.writeSide, (format("%1% %2% %3% %4%") + % (worker.getNrLocalBuilds() < settings.maxBuildJobs ? "1" : "0") + % drv.platform % drvPath % concatStringsSep(",", features)).str()); + + /* Read the first line of input, which should be a word indicating + whether the hook wishes to perform the build. */ + string reply; + while (true) { + string s = readLine(worker.hook->fromHook.readSide); + if (string(s, 0, 2) == "# ") { + reply = string(s, 2); + break; + } + s += "\n"; + writeToStderr(s); + } + + debug(format("hook reply is `%1%'") % reply); + + if (reply == "decline" || reply == "postpone") + return reply == "decline" ? rpDecline : rpPostpone; + else if (reply != "accept") + throw Error(format("bad hook reply `%1%'") % reply); + + printMsg(lvlTalkative, format("using hook to build path(s) %1%") + % showPaths(outputPaths(drv.outputs))); + + hook = worker.hook; + worker.hook.reset(); + + /* Tell the hook all the inputs that have to be copied to the + remote system. This unfortunately has to contain the entire + derivation closure to ensure that the validity invariant holds + on the remote system. (I.e., it's unfortunate that we have to + list it since the remote system *probably* already has it.) */ + PathSet allInputs; + allInputs.insert(inputPaths.begin(), inputPaths.end()); + computeFSClosure(worker.store, drvPath, allInputs); + + string s; + foreach (PathSet::iterator, i, allInputs) s += *i + " "; + writeLine(hook->toHook.writeSide, s); + + /* Tell the hooks the outputs that have to be copied back from the + remote system. */ + s = ""; + foreach (DerivationOutputs::iterator, i, drv.outputs) + s += i->second.path + " "; + writeLine(hook->toHook.writeSide, s); + + hook->toHook.writeSide.close(); + + /* Create the log file and pipe. */ + Path logFile = openLogFile(); + + set<int> fds; + fds.insert(hook->fromHook.readSide); + fds.insert(hook->builderOut.readSide); + worker.childStarted(shared_from_this(), hook->pid, fds, false, false); + + if (settings.printBuildTrace) + printMsg(lvlError, format("@ build-started %1% - %2% %3%") + % drvPath % drv.platform % logFile); + + return rpAccept; +} + + +void chmod_(const Path & path, mode_t mode) +{ + if (chmod(path.c_str(), mode) == -1) + throw SysError(format("setting permissions on `%1%'") % path); +} + + +int childEntry(void * arg) +{ + ((DerivationGoal *) arg)->initChild(); + return 1; +} + + +void DerivationGoal::startBuilder() +{ + startNest(nest, lvlInfo, format(repair ? "repairing path(s) %1%" : "building path(s) %1%") % showPaths(missingPaths)); + + /* Right platform? */ + if (!canBuildLocally(drv.platform)) { + if (settings.printBuildTrace) + printMsg(lvlError, format("@ unsupported-platform %1% %2%") % drvPath % drv.platform); + throw Error( + format("a `%1%' is required to build `%3%', but I am a `%2%'") + % drv.platform % settings.thisSystem % drvPath); + } + + /* Construct the environment passed to the builder. */ + + /* Most shells initialise PATH to some default (/bin:/usr/bin:...) when + PATH is not set. We don't want this, so we fill it in with some dummy + value. */ + env["PATH"] = "/path-not-set"; + + /* Set HOME to a non-existing path to prevent certain programs from using + /etc/passwd (or NIS, or whatever) to locate the home directory (for + example, wget looks for ~/.wgetrc). I.e., these tools use /etc/passwd + if HOME is not set, but they will just assume that the settings file + they are looking for does not exist if HOME is set but points to some + non-existing path. */ + Path homeDir = "/homeless-shelter"; + env["HOME"] = homeDir; + + /* Tell the builder where the Nix store is. Usually they + shouldn't care, but this is useful for purity checking (e.g., + the compiler or linker might only want to accept paths to files + in the store or in the build directory). */ + env["NIX_STORE"] = settings.nixStore; + + /* The maximum number of cores to utilize for parallel building. */ + env["NIX_BUILD_CORES"] = (format("%d") % settings.buildCores).str(); + + /* Add all bindings specified in the derivation. */ + foreach (StringPairs::iterator, i, drv.env) + env[i->first] = i->second; + + /* Create a temporary directory where the build will take + place. */ + tmpDir = createTempDir("", "nix-build-" + storePathToName(drvPath), false, false, 0700); + + /* For convenience, set an environment pointing to the top build + directory. */ + env["NIX_BUILD_TOP"] = tmpDir; + + /* Also set TMPDIR and variants to point to this directory. */ + env["TMPDIR"] = env["TEMPDIR"] = env["TMP"] = env["TEMP"] = tmpDir; + + /* Explicitly set PWD to prevent problems with chroot builds. In + particular, dietlibc cannot figure out the cwd because the + inode of the current directory doesn't appear in .. (because + getdents returns the inode of the mount point). */ + env["PWD"] = tmpDir; + + /* Compatibility hack with Nix <= 0.7: if this is a fixed-output + derivation, tell the builder, so that for instance `fetchurl' + can skip checking the output. On older Nixes, this environment + variable won't be set, so `fetchurl' will do the check. */ + if (fixedOutput) env["NIX_OUTPUT_CHECKED"] = "1"; + + /* *Only* if this is a fixed-output derivation, propagate the + values of the environment variables specified in the + `impureEnvVars' attribute to the builder. This allows for + instance environment variables for proxy configuration such as + `http_proxy' to be easily passed to downloaders like + `fetchurl'. Passing such environment variables from the caller + to the builder is generally impure, but the output of + fixed-output derivations is by definition pure (since we + already know the cryptographic hash of the output). */ + if (fixedOutput) { + Strings varNames = tokenizeString<Strings>(get(drv.env, "impureEnvVars")); + foreach (Strings::iterator, i, varNames) env[*i] = getEnv(*i); + } + + /* The `exportReferencesGraph' feature allows the references graph + to be passed to a builder. This attribute should be a list of + pairs [name1 path1 name2 path2 ...]. The references graph of + each `pathN' will be stored in a text file `nameN' in the + temporary build directory. The text files have the format used + by `nix-store --register-validity'. However, the deriver + fields are left empty. */ + string s = get(drv.env, "exportReferencesGraph"); + 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(); ) { + string fileName = *i++; + checkStoreName(fileName); /* !!! abuse of this function */ + + /* Check that the store path is valid. */ + Path storePath = *i++; + if (!isInStore(storePath)) + throw BuildError(format("`exportReferencesGraph' contains a non-store path `%1%'") + % storePath); + storePath = toStorePath(storePath); + if (!worker.store.isValidPath(storePath)) + throw BuildError(format("`exportReferencesGraph' contains an invalid path `%1%'") + % storePath); + + /* If there are derivations in the graph, then include their + outputs as well. This is useful if you want to do things + like passing all build-time dependencies of some path to a + derivation that builds a NixOS DVD image. */ + PathSet paths, paths2; + computeFSClosure(worker.store, storePath, paths); + paths2 = paths; + + foreach (PathSet::iterator, j, paths2) { + if (isDerivation(*j)) { + Derivation drv = derivationFromPath(worker.store, *j); + foreach (DerivationOutputs::iterator, k, drv.outputs) + computeFSClosure(worker.store, k->second.path, paths); + } + } + + /* Write closure info to `fileName'. */ + writeFile(tmpDir + "/" + fileName, + worker.store.makeValidityRegistration(paths, false, false)); + } + + + /* If `build-users-group' is not empty, then we have to build as + one of the members of that group. */ + if (settings.buildUsersGroup != "") { + buildUser.acquire(); + assert(buildUser.getUID() != 0); + assert(buildUser.getGID() != 0); + + /* Make sure that no other processes are executing under this + uid. */ + buildUser.kill(); + + /* Change ownership of the temporary build directory. */ + if (chown(tmpDir.c_str(), buildUser.getUID(), buildUser.getGID()) == -1) + throw SysError(format("cannot change ownership of `%1%'") % tmpDir); + + /* Check that the Nix store has the appropriate permissions, + i.e., owned by root and mode 1775 (sticky bit on so that + the builder can create its output but not mess with the + outputs of other processes). */ + struct stat st; + if (stat(settings.nixStore.c_str(), &st) == -1) + throw SysError(format("cannot stat `%1%'") % settings.nixStore); + if (!(st.st_mode & S_ISVTX) || + ((st.st_mode & S_IRWXG) != S_IRWXG) || + (st.st_gid != buildUser.getGID())) + throw Error(format( + "builder does not have write permission to `%2%'; " + "try `chgrp %1% %2%; chmod 1775 %2%'") + % buildUser.getGID() % settings.nixStore); + } + + + /* Are we doing a chroot build? Note that fixed-output + derivations are never done in a chroot, mainly so that + functions like fetchurl (which needs a proper /etc/resolv.conf) + work properly. Purity checking for fixed-output derivations + is somewhat pointless anyway. */ + useChroot = settings.useChroot; + + if (fixedOutput) useChroot = false; + + /* Hack to allow derivations to disable chroot builds. */ + if (get(drv.env, "__noChroot") == "1") useChroot = false; + + if (useChroot) { +#if CHROOT_ENABLED + /* Create a temporary directory in which we set up the chroot + environment using bind-mounts. We put it in the Nix store + to ensure that we can create hard-links to non-directory + inputs in the fake Nix store in the chroot (see below). */ + chrootRootDir = drvPath + ".chroot"; + if (pathExists(chrootRootDir)) deletePath(chrootRootDir); + + /* Clean up the chroot directory automatically. */ + autoDelChroot = boost::shared_ptr<AutoDelete>(new AutoDelete(chrootRootDir)); + + printMsg(lvlChatty, format("setting up chroot environment in `%1%'") % chrootRootDir); + + /* Create a writable /tmp in the chroot. Many builders need + this. (Of course they should really respect $TMPDIR + instead.) */ + Path chrootTmpDir = chrootRootDir + "/tmp"; + createDirs(chrootTmpDir); + 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 + Samba-in-QEMU. */ + createDirs(chrootRootDir + "/etc"); + + writeFile(chrootRootDir + "/etc/passwd", + (format( + "nixbld:x:%1%:%2%:Nix build user:/:/noshell\n" + "nobody:x:65534:65534:Nobody:/:/noshell\n") + % (buildUser.enabled() ? buildUser.getUID() : getuid()) + % (buildUser.enabled() ? buildUser.getGID() : getgid())).str()); + + /* Declare the build user's group so that programs get a consistent + view of the system (e.g., "id -gn"). */ + writeFile(chrootRootDir + "/etc/group", + (format("nixbld:!:%1%:\n") + % (buildUser.enabled() ? buildUser.getGID() : getgid())).str()); + + /* Create /etc/hosts with localhost entry. */ + writeFile(chrootRootDir + "/etc/hosts", "127.0.0.1 localhost\n"); + + /* Bind-mount a user-configurable set of directories from the + host file system. */ + foreach (StringSet::iterator, i, settings.dirsInChroot) { + size_t p = i->find('='); + if (p == string::npos) + dirsInChroot[*i] = *i; + else + dirsInChroot[string(*i, 0, p)] = string(*i, p + 1); + } + dirsInChroot[tmpDir] = tmpDir; + + /* Make the closure of the inputs available in the chroot, + rather than the whole Nix store. This prevents any access + to undeclared dependencies. Directories are bind-mounted, + while other inputs are hard-linked (since only directories + can be bind-mounted). !!! As an extra security + precaution, make the fake Nix store only writable by the + build user. */ + createDirs(chrootRootDir + settings.nixStore); + chmod_(chrootRootDir + settings.nixStore, 01777); + + foreach (PathSet::iterator, i, inputPaths) { + struct stat st; + if (lstat(i->c_str(), &st)) + throw SysError(format("getting attributes of path `%1%'") % *i); + if (S_ISDIR(st.st_mode)) + dirsInChroot[*i] = *i; + else { + Path p = chrootRootDir + *i; + if (link(i->c_str(), p.c_str()) == -1) { + /* 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'. */ + if (errno != EMLINK) + throw SysError(format("linking `%1%' to `%2%'") % p % *i); + StringSink sink; + dumpPath(*i, sink); + StringSource source(sink.s); + restorePath(p, source); + } + + regularInputPaths.insert(*i); + } + } + + /* If we're repairing, it's possible that we're rebuilding a + path that is in settings.dirsInChroot (typically the + dependencies of /bin/sh). Throw them out. */ + if (repair) + foreach (DerivationOutputs::iterator, i, drv.outputs) + dirsInChroot.erase(i->second.path); + +#else + throw Error("chroot builds are not supported on this platform"); +#endif + } + + else { + + if (pathExists(homeDir)) + throw Error(format("directory `%1%' exists; please remove it") % homeDir); + + /* We're not doing a chroot build, but we have some valid + output paths. Since we can't just overwrite or delete + them, we have to do hash rewriting: i.e. in the + environment/arguments passed to the build, we replace the + hashes of the valid outputs with unique dummy strings; + after the build, we discard the redirected outputs + corresponding to the valid outputs, and rewrite the + contents of the new outputs to replace the dummy strings + with the actual hashes. */ + if (validPaths.size() > 0) + //throw Error(format("derivation `%1%' is blocked by its output path(s) %2%") % drvPath % showPaths(validPaths)); + foreach (PathSet::iterator, i, validPaths) + redirectedOutputs.insert(addHashRewrite(*i)); + + /* If we're repairing, then we don't want to delete the + corrupt outputs in advance. So rewrite them as well. */ + if (repair) + foreach (PathSet::iterator, i, missingPaths) + if (worker.store.isValidPath(*i) && pathExists(*i)) + redirectedBadOutputs[*i] = addHashRewrite(*i); + } + + + /* Run the builder. */ + printMsg(lvlChatty, format("executing builder `%1%'") % + drv.builder); + + /* Create the log file. */ + Path logFile = openLogFile(); + + /* Create a pipe to get the output of the builder. */ + builderOut.create(); + + /* Fork a child to build the package. Note that while we + currently use forks to run and wait for the children, it + shouldn't be hard to use threads for this on systems where + fork() is unavailable or inefficient. + + If we're building in a chroot, then also set up private + namespaces for the build: + + - The PID namespace causes the build to start as PID 1. + Processes outside of the chroot are not visible to those on + the inside, but processes inside the chroot are visible from + the outside (though with different PIDs). + + - The private mount namespace ensures that all the bind mounts + we do will only show up in this process and its children, and + will disappear automatically when we're done. + + - The private network namespace ensures that the builder cannot + talk to the outside world (or vice versa). It only has a + private loopback interface. + + - The IPC namespace prevents the builder from communicating + with outside processes using SysV IPC mechanisms (shared + memory, message queues, semaphores). It also ensures that + all IPC objects are destroyed when the builder exits. + + - The UTS namespace ensures that builders see a hostname of + localhost rather than the actual hostname. + */ +#if CHROOT_ENABLED + if (useChroot) { + char stack[32 * 1024]; + pid = clone(childEntry, stack + sizeof(stack) - 8, + CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWNET | CLONE_NEWIPC | CLONE_NEWUTS | SIGCHLD, this); + } else +#endif + { + pid = fork(); + if (pid == 0) initChild(); + } + + if (pid == -1) throw SysError("unable to fork"); + + /* parent */ + pid.setSeparatePG(true); + builderOut.writeSide.close(); + worker.childStarted(shared_from_this(), pid, + singleton<set<int> >(builderOut.readSide), true, true); + + if (settings.printBuildTrace) { + printMsg(lvlError, format("@ build-started %1% - %2% %3%") + % drvPath % drv.platform % logFile); + } +} + + +void DerivationGoal::initChild() +{ + /* Warning: in the child we should absolutely not make any SQLite + calls! */ + + bool inSetup = true; + + try { /* child */ + +#if CHROOT_ENABLED + if (useChroot) { + /* Initialise the loopback interface. */ + AutoCloseFD fd(socket(PF_INET, SOCK_DGRAM, IPPROTO_IP)); + if (fd == -1) throw SysError("cannot open IP socket"); + + struct ifreq ifr; + strcpy(ifr.ifr_name, "lo"); + ifr.ifr_flags = IFF_UP | IFF_LOOPBACK | IFF_RUNNING; + if (ioctl(fd, SIOCSIFFLAGS, &ifr) == -1) + throw SysError("cannot set loopback interface flags"); + + fd.close(); + + /* Set the hostname etc. to fixed values. */ + char hostname[] = "localhost"; + sethostname(hostname, sizeof(hostname)); + 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<Strings>(readFile("/proc/self/mountinfo", true), "\n"); + foreach (Strings::iterator, i, mounts) { + vector<string> fields = tokenizeString<vector<string> >(*i, " "); + string fs = decodeOctalEscaped(fields.at(4)); + if (mount(0, fs.c_str(), 0, MS_PRIVATE, 0) == -1) + throw SysError(format("unable to make filesystem `%1%' private") % fs); + } + + /* Bind-mount all the directories from the "host" + filesystem that we want in the chroot + environment. */ + foreach (DirsInChroot::iterator, i, dirsInChroot) { + struct stat st; + Path source = i->second; + Path target = chrootRootDir + i->first; + if (source == "/proc") continue; // backwards compatibility + debug(format("bind mounting `%1%' to `%2%'") % source % target); + if (stat(source.c_str(), &st) == -1) + throw SysError(format("getting attributes of path `%1%'") % source); + if (S_ISDIR(st.st_mode)) + createDirs(target); + else { + createDirs(dirOf(target)); + writeFile(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"); + + /* Mount a new tmpfs on /dev/shm to ensure that whatever + the builder puts in /dev/shm is cleaned up automatically. */ + if (pathExists("/dev/shm")) + if (mount("none", (chrootRootDir + "/dev/shm").c_str(), "tmpfs", 0, 0) == -1) + throw SysError("mounting /dev/shm"); + + /* Do the chroot(). Below we do a chdir() to the + temporary build directory to make sure the current + directory is in the chroot. (Actually the order + doesn't matter, since due to the bind mount tmpDir and + tmpRootDit/tmpDir are the same directories.) */ + if (chroot(chrootRootDir.c_str()) == -1) + throw SysError(format("cannot change root directory to `%1%'") % chrootRootDir); + } +#endif + + commonChildInit(builderOut); + + if (chdir(tmpDir.c_str()) == -1) + throw SysError(format("changing into `%1%'") % tmpDir); + + /* Close all other file descriptors. */ + closeMostFDs(set<int>()); + +#ifdef CAN_DO_LINUX32_BUILDS + /* Change the personality to 32-bit if we're doing an + i686-linux build on an x86_64-linux machine. */ + struct utsname utsbuf; + uname(&utsbuf); + if (drv.platform == "i686-linux" && + (settings.thisSystem == "x86_64-linux" || + (!strcmp(utsbuf.sysname, "Linux") && !strcmp(utsbuf.machine, "x86_64")))) { + if (personality(0x0008 | 0x8000000 /* == PER_LINUX32_3GB */) == -1) + throw SysError("cannot set i686-linux personality"); + } + + /* Impersonate a Linux 2.6 machine to get some determinism in + builds that depend on the kernel version. */ + if ((drv.platform == "i686-linux" || drv.platform == "x86_64-linux") && settings.impersonateLinux26) { + int cur = personality(0xffffffff); + if (cur != -1) personality(cur | 0x0020000 /* == UNAME26 */); + } +#endif + + /* Fill in the environment. */ + Strings envStrs; + foreach (Environment::const_iterator, i, env) + envStrs.push_back(rewriteHashes(i->first + "=" + i->second, rewritesToTmp)); + const char * * envArr = strings2CharPtrs(envStrs); + + Path program = drv.builder.c_str(); + std::vector<const char *> args; /* careful with c_str()! */ + string user; /* must be here for its c_str()! */ + + /* If we are running in `build-users' mode, then switch to the + user we allocated above. Make sure that we drop all root + privileges. Note that above we have closed all file + descriptors except std*, so that's safe. Also note that + setuid() when run as root sets the real, effective and + saved UIDs. */ + if (buildUser.enabled()) { + printMsg(lvlChatty, format("switching to user `%1%'") % buildUser.getUser()); + + if (setgroups(0, 0) == -1) + throw SysError("cannot clear the set of supplementary groups"); + + if (setgid(buildUser.getGID()) == -1 || + getgid() != buildUser.getGID() || + getegid() != buildUser.getGID()) + throw SysError("setgid failed"); + + if (setuid(buildUser.getUID()) == -1 || + getuid() != buildUser.getUID() || + geteuid() != buildUser.getUID()) + throw SysError("setuid failed"); + } + + /* Fill in the arguments. */ + string builderBasename = baseNameOf(drv.builder); + args.push_back(builderBasename.c_str()); + foreach (Strings::iterator, i, drv.args) + args.push_back(rewriteHashes(*i, rewritesToTmp).c_str()); + args.push_back(0); + + restoreSIGPIPE(); + + /* Execute the program. This should not return. */ + inSetup = false; + execve(program.c_str(), (char * *) &args[0], (char * *) envArr); + + throw SysError(format("executing `%1%'") % drv.builder); + + } catch (std::exception & e) { + writeToStderr("build error: " + string(e.what()) + "\n"); + _exit(inSetup ? childSetupFailed : 1); + } + + abort(); /* never reached */ +} + + +/* Parse a list of reference specifiers. Each element must either be + a store path, or the symbolic name of the output of the derivation + (such as `out'). */ +PathSet parseReferenceSpecifiers(const Derivation & drv, string attr) +{ + PathSet result; + Paths paths = tokenizeString<Paths>(attr); + foreach (Strings::iterator, i, paths) { + if (isStorePath(*i)) + result.insert(*i); + else if (drv.outputs.find(*i) != drv.outputs.end()) + result.insert(drv.outputs.find(*i)->second.path); + else throw BuildError( + format("derivation contains an illegal reference specifier `%1%'") + % *i); + } + return result; +} + + +void DerivationGoal::computeClosure() +{ + map<Path, PathSet> allReferences; + map<Path, HashResult> contentHashes; + + /* When using a build hook, the build hook can register the output + as valid (by doing `nix-store --import'). If so we don't have + to do anything here. */ + if (hook) { + bool allValid = true; + foreach (DerivationOutputs::iterator, i, drv.outputs) + if (!worker.store.isValidPath(i->second.path)) allValid = false; + if (allValid) return; + } + + /* Check whether the output paths were created, and grep each + output path to determine what other paths it references. Also make all + output paths read-only. */ + foreach (DerivationOutputs::iterator, i, drv.outputs) { + Path path = i->second.path; + if (missingPaths.find(path) == missingPaths.end()) continue; + + if (!pathExists(path)) { + throw BuildError( + format("builder for `%1%' failed to produce output path `%2%'") + % drvPath % path); + } + + struct stat st; + if (lstat(path.c_str(), &st) == -1) + throw SysError(format("getting attributes of path `%1%'") % path); + + startNest(nest, lvlTalkative, + format("scanning for references inside `%1%'") % path); + + /* Check that fixed-output derivations produced the right + outputs (i.e., the content hash should match the specified + hash). */ + if (i->second.hash != "") { + + bool recursive; HashType ht; Hash h; + i->second.parseHashInfo(recursive, ht, h); + + if (!recursive) { + /* The output path should be a regular file without + execute permission. */ + if (!S_ISREG(st.st_mode) || (st.st_mode & S_IXUSR) != 0) + throw BuildError( + format("output path `%1% should be a non-executable regular file") + % path); + } + + /* Check the hash. */ + Hash h2 = recursive ? hashPath(ht, path).first : hashFile(ht, path); + if (h != h2) + throw BuildError( + format("output path `%1%' should have %2% hash `%3%', instead has `%4%'") + % path % i->second.hashAlgo % printHash16or32(h) % printHash16or32(h2)); + } + + /* Get rid of all weird permissions. This also checks that + all files are owned by the build user, if applicable. */ + canonicalisePathMetaData(path, + buildUser.enabled() && rewrittenPaths.find(path) == rewrittenPaths.end() ? buildUser.getUID() : -1, inodesSeen); + + /* For this output path, find the references to other paths + contained in it. Compute the SHA-256 NAR hash at the same + time. The hash is stored in the database so that we can + verify later on whether nobody has messed with the store. */ + HashResult hash; + PathSet references = scanForReferences(path, allPaths, hash); + contentHashes[path] = hash; + + /* For debugging, print out the referenced and unreferenced + paths. */ + foreach (PathSet::iterator, i, inputPaths) { + PathSet::iterator j = references.find(*i); + if (j == references.end()) + debug(format("unreferenced input: `%1%'") % *i); + else + debug(format("referenced input: `%1%'") % *i); + } + + allReferences[path] = references; + + /* If the derivation specifies an `allowedReferences' + attribute (containing a list of paths that the output may + refer to), check that all references are in that list. !!! + allowedReferences should really be per-output. */ + if (drv.env.find("allowedReferences") != drv.env.end()) { + PathSet allowed = parseReferenceSpecifiers(drv, get(drv.env, "allowedReferences")); + foreach (PathSet::iterator, i, references) + if (allowed.find(*i) == allowed.end()) + throw BuildError(format("output is not allowed to refer to path `%1%'") % *i); + } + + worker.store.optimisePath(path); // FIXME: combine with scanForReferences() + + worker.store.markContentsGood(path); + } + + /* Register each output path as valid, and register the sets of + paths referenced by each of them. If there are cycles in the + outputs, this will fail. */ + ValidPathInfos infos; + foreach (PathSet::iterator, i, missingPaths) { + ValidPathInfo info; + info.path = *i; + info.hash = contentHashes[*i].first; + info.narSize = contentHashes[*i].second; + info.references = allReferences[*i]; + info.deriver = drvPath; + infos.push_back(info); + } + worker.store.registerValidPaths(infos); +} + + +string drvsLogDir = "drvs"; + + +Path DerivationGoal::openLogFile() +{ + logSize = 0; + + if (!settings.keepLog) return ""; + + string baseName = baseNameOf(drvPath); + + /* Create a log file. */ + Path dir = (format("%1%/%2%/%3%/") % settings.nixLogDir % drvsLogDir % string(baseName, 0, 2)).str(); + createDirs(dir); + + if (settings.compressLog) { + + Path logFileName = (format("%1%/%2%.bz2") % dir % string(baseName, 2)).str(); + AutoCloseFD fd = open(logFileName.c_str(), O_CREAT | O_WRONLY | O_TRUNC, 0666); + if (fd == -1) throw SysError(format("creating log file `%1%'") % logFileName); + closeOnExec(fd); + + if (!(fLogFile = fdopen(fd.borrow(), "w"))) + throw SysError(format("opening file `%1%'") % logFileName); + + int err; + if (!(bzLogFile = BZ2_bzWriteOpen(&err, fLogFile, 9, 0, 0))) + throw Error(format("cannot open compressed log file `%1%'") % logFileName); + + return logFileName; + + } else { + Path logFileName = (format("%1%/%2%") % dir % string(baseName, 2)).str(); + fdLogFile = open(logFileName.c_str(), O_CREAT | O_WRONLY | O_TRUNC, 0666); + if (fdLogFile == -1) throw SysError(format("creating log file `%1%'") % logFileName); + closeOnExec(fdLogFile); + return logFileName; + } +} + + +void DerivationGoal::closeLogFile() +{ + if (bzLogFile) { + int err; + BZ2_bzWriteClose(&err, bzLogFile, 0, 0, 0); + bzLogFile = 0; + if (err != BZ_OK) throw Error(format("cannot close compressed log file (BZip2 error = %1%)") % err); + } + + if (fLogFile) { + fclose(fLogFile); + fLogFile = 0; + } + + fdLogFile.close(); +} + + +void DerivationGoal::deleteTmpDir(bool force) +{ + if (tmpDir != "") { + if (settings.keepFailed && !force) { + printMsg(lvlError, + format("note: keeping build directory `%2%'") + % drvPath % tmpDir); + chmod(tmpDir.c_str(), 0755); + } + else + deletePath(tmpDir); + tmpDir = ""; + } +} + + +void DerivationGoal::handleChildOutput(int fd, const string & data) +{ + if ((hook && fd == hook->builderOut.readSide) || + (!hook && fd == builderOut.readSide)) + { + logSize += data.size(); + if (settings.maxLogSize && logSize > settings.maxLogSize) { + printMsg(lvlError, + format("%1% killed after writing more than %2% bytes of log output") + % getName() % settings.maxLogSize); + cancel(true); // not really a timeout, but close enough + return; + } + if (verbosity >= settings.buildVerbosity) + writeToStderr(data); + if (bzLogFile) { + int err; + BZ2_bzWrite(&err, bzLogFile, (unsigned char *) data.data(), data.size()); + if (err != BZ_OK) throw Error(format("cannot write to compressed log file (BZip2 error = %1%)") % err); + } else if (fdLogFile != -1) + writeFull(fdLogFile, (unsigned char *) data.data(), data.size()); + } + + if (hook && fd == hook->fromHook.readSide) + writeToStderr(data); +} + + +void DerivationGoal::handleEOF(int fd) +{ + worker.wakeUp(shared_from_this()); +} + + +PathSet DerivationGoal::checkPathValidity(bool returnValid, bool checkHash) +{ + PathSet result; + foreach (DerivationOutputs::iterator, i, drv.outputs) { + if (!wantOutput(i->first, wantedOutputs)) continue; + bool good = + worker.store.isValidPath(i->second.path) && + (!checkHash || worker.store.pathContentsGood(i->second.path)); + if (good == returnValid) result.insert(i->second.path); + } + return result; +} + + +bool DerivationGoal::pathFailed(const Path & path) +{ + if (!settings.cacheFailure) return false; + + if (!worker.store.hasPathFailed(path)) return false; + + printMsg(lvlError, format("builder for `%1%' failed previously (cached)") % path); + + if (settings.printBuildTrace) + printMsg(lvlError, format("@ build-failed %1% - cached") % drvPath); + + worker.permanentFailure = true; + amDone(ecFailed); + + return true; +} + + +Path DerivationGoal::addHashRewrite(const Path & path) +{ + string h1 = string(path, settings.nixStore.size() + 1, 32); + string h2 = string(printHash32(hashString(htSHA256, "rewrite:" + drvPath + ":" + path)), 0, 32); + Path p = settings.nixStore + "/" + h2 + string(path, settings.nixStore.size() + 33); + if (pathExists(p)) deletePath(p); + assert(path.size() == p.size()); + rewritesToTmp[h1] = h2; + rewritesFromTmp[h2] = h1; + return p; +} + + +////////////////////////////////////////////////////////////////////// + + +class SubstitutionGoal : public Goal +{ + friend class Worker; + +private: + /* The store path that should be realised through a substitute. */ + Path storePath; + + /* The remaining substituters. */ + Paths subs; + + /* The current substituter. */ + Path sub; + + /* Whether any substituter can realise this path */ + bool hasSubstitute; + + /* Path info returned by the substituter's query info operation. */ + SubstitutablePathInfo info; + + /* Pipe for the substituter's standard output. */ + Pipe outPipe; + + /* Pipe for the substituter's standard error. */ + Pipe logPipe; + + /* The process ID of the builder. */ + Pid pid; + + /* Lock on the store path. */ + boost::shared_ptr<PathLocks> outputLock; + + /* Whether to try to repair a valid path. */ + bool repair; + + /* Location where we're downloading the substitute. Differs from + storePath when doing a repair. */ + Path destPath; + + typedef void (SubstitutionGoal::*GoalState)(); + GoalState state; + +public: + SubstitutionGoal(const Path & storePath, Worker & worker, bool repair = false); + ~SubstitutionGoal(); + + void cancel(bool timeout); + + void work(); + + /* The states. */ + void init(); + void tryNext(); + void gotInfo(); + void referencesValid(); + void tryToRun(); + void finished(); + + /* Callback used by the worker to write to the log. */ + void handleChildOutput(int fd, const string & data); + void handleEOF(int fd); + + Path getStorePath() { return storePath; } +}; + + +SubstitutionGoal::SubstitutionGoal(const Path & storePath, Worker & worker, bool repair) + : Goal(worker) + , hasSubstitute(false) + , repair(repair) +{ + this->storePath = storePath; + state = &SubstitutionGoal::init; + name = (format("substitution of `%1%'") % storePath).str(); + trace("created"); +} + + +SubstitutionGoal::~SubstitutionGoal() +{ + if (pid != -1) worker.childTerminated(pid); +} + + +void SubstitutionGoal::cancel(bool timeout) +{ + if (settings.printBuildTrace && timeout) + printMsg(lvlError, format("@ substituter-failed %1% timeout") % storePath); + if (pid != -1) { + pid_t savedPid = pid; + pid.kill(); + worker.childTerminated(savedPid); + } + amDone(ecFailed); +} + + +void SubstitutionGoal::work() +{ + (this->*state)(); +} + + +void SubstitutionGoal::init() +{ + trace("init"); + + worker.store.addTempRoot(storePath); + + /* If the path already exists we're done. */ + if (!repair && worker.store.isValidPath(storePath)) { + amDone(ecSuccess); + return; + } + + if (settings.readOnlyMode) + throw Error(format("cannot substitute path `%1%' - no write access to the Nix store") % storePath); + + subs = settings.substituters; + + tryNext(); +} + + +void SubstitutionGoal::tryNext() +{ + trace("trying next substituter"); + + if (subs.size() == 0) { + /* None left. Terminate this goal and let someone else deal + with it. */ + debug(format("path `%1%' is required, but there is no substituter that can build it") % storePath); + /* Hack: don't indicate failure if there were no substituters. + In that case the calling derivation should just do a + build. */ + amDone(hasSubstitute ? ecFailed : ecNoSubstituters); + return; + } + + sub = subs.front(); + subs.pop_front(); + + SubstitutablePathInfos infos; + PathSet dummy(singleton<PathSet>(storePath)); + worker.store.querySubstitutablePathInfos(sub, dummy, infos); + SubstitutablePathInfos::iterator k = infos.find(storePath); + if (k == infos.end()) { tryNext(); return; } + info = k->second; + hasSubstitute = true; + + /* To maintain the closure invariant, we first have to realise the + paths referenced by this one. */ + foreach (PathSet::iterator, i, info.references) + if (*i != storePath) /* ignore self-references */ + addWaitee(worker.makeSubstitutionGoal(*i)); + + if (waitees.empty()) /* to prevent hang (no wake-up event) */ + referencesValid(); + else + state = &SubstitutionGoal::referencesValid; +} + + +void SubstitutionGoal::referencesValid() +{ + trace("all references realised"); + + if (nrFailed > 0) { + debug(format("some references of path `%1%' could not be realised") % storePath); + amDone(nrNoSubstituters > 0 || nrIncompleteClosure > 0 ? ecIncompleteClosure : ecFailed); + return; + } + + foreach (PathSet::iterator, i, info.references) + if (*i != storePath) /* ignore self-references */ + assert(worker.store.isValidPath(*i)); + + state = &SubstitutionGoal::tryToRun; + worker.wakeUp(shared_from_this()); +} + + +void SubstitutionGoal::tryToRun() +{ + trace("trying to run"); + + /* Make sure that we are allowed to start a build. Note that even + is maxBuildJobs == 0 (no local builds allowed), we still allow + a substituter to run. This is because substitutions cannot be + distributed to another machine via the build hook. */ + if (worker.getNrLocalBuilds() >= (settings.maxBuildJobs == 0 ? 1 : settings.maxBuildJobs)) { + worker.waitForBuildSlot(shared_from_this()); + return; + } + + /* Maybe a derivation goal has already locked this path + (exceedingly unlikely, since it should have used a substitute + first, but let's be defensive). */ + outputLock.reset(); // make sure this goal's lock is gone + if (pathIsLockedByMe(storePath)) { + debug(format("restarting substitution of `%1%' because it's locked by another goal") + % storePath); + worker.waitForAnyGoal(shared_from_this()); + return; /* restart in the tryToRun() state when another goal finishes */ + } + + /* Acquire a lock on the output path. */ + outputLock = boost::shared_ptr<PathLocks>(new PathLocks); + if (!outputLock->lockPaths(singleton<PathSet>(storePath), "", false)) { + worker.waitForAWhile(shared_from_this()); + return; + } + + /* Check again whether the path is invalid. */ + if (!repair && worker.store.isValidPath(storePath)) { + debug(format("store path `%1%' has become valid") % storePath); + outputLock->setDeletion(true); + amDone(ecSuccess); + return; + } + + printMsg(lvlInfo, format("fetching path `%1%'...") % storePath); + + outPipe.create(); + logPipe.create(); + + destPath = repair ? storePath + ".tmp" : storePath; + + /* Remove the (stale) output path if it exists. */ + if (pathExists(destPath)) + deletePath(destPath); + + worker.store.setSubstituterEnv(); + + /* Fill in the arguments. */ + Strings args; + args.push_back(baseNameOf(sub)); + args.push_back("--substitute"); + args.push_back(storePath); + args.push_back(destPath); + const char * * argArr = strings2CharPtrs(args); + + /* Fork the substitute program. */ + pid = maybeVfork(); + + switch (pid) { + + case -1: + throw SysError("unable to fork"); + + case 0: + try { /* child */ + + commonChildInit(logPipe); + + if (dup2(outPipe.writeSide, STDOUT_FILENO) == -1) + throw SysError("cannot dup output pipe into stdout"); + + execv(sub.c_str(), (char * *) argArr); + + throw SysError(format("executing `%1%'") % sub); + + } catch (std::exception & e) { + writeToStderr("substitute error: " + string(e.what()) + "\n"); + } + _exit(1); + } + + /* parent */ + pid.setSeparatePG(true); + pid.setKillSignal(SIGTERM); + outPipe.writeSide.close(); + logPipe.writeSide.close(); + worker.childStarted(shared_from_this(), + pid, singleton<set<int> >(logPipe.readSide), true, true); + + state = &SubstitutionGoal::finished; + + if (settings.printBuildTrace) + printMsg(lvlError, format("@ substituter-started %1% %2%") % storePath % sub); +} + + +void SubstitutionGoal::finished() +{ + trace("substitute finished"); + + /* Since we got an EOF on the logger pipe, the substitute is + presumed to have terminated. */ + pid_t savedPid = pid; + int status = pid.wait(true); + + /* So the child is gone now. */ + worker.childTerminated(savedPid); + + /* Close the read side of the logger pipe. */ + logPipe.readSide.close(); + + /* Get the hash info from stdout. */ + string dummy = readLine(outPipe.readSide); + string expectedHashStr = statusOk(status) ? readLine(outPipe.readSide) : ""; + outPipe.readSide.close(); + + /* Check the exit status and the build result. */ + HashResult hash; + try { + + if (!statusOk(status)) + throw SubstError(format("fetching path `%1%' %2%") + % storePath % statusToString(status)); + + if (!pathExists(destPath)) + throw SubstError(format("substitute did not produce path `%1%'") % destPath); + + hash = hashPath(htSHA256, destPath); + + /* Verify the expected hash we got from the substituer. */ + if (expectedHashStr != "") { + size_t n = expectedHashStr.find(':'); + if (n == string::npos) + throw Error(format("bad hash from substituter: %1%") % expectedHashStr); + HashType hashType = parseHashType(string(expectedHashStr, 0, n)); + if (hashType == htUnknown) + throw Error(format("unknown hash algorithm in `%1%'") % expectedHashStr); + Hash expectedHash = parseHash16or32(hashType, string(expectedHashStr, n + 1)); + Hash actualHash = hashType == htSHA256 ? hash.first : hashPath(hashType, destPath).first; + if (expectedHash != actualHash) + throw SubstError(format("hash mismatch in downloaded path `%1%': expected %2%, got %3%") + % storePath % printHash(expectedHash) % printHash(actualHash)); + } + + } catch (SubstError & e) { + + printMsg(lvlInfo, e.msg()); + + if (settings.printBuildTrace) { + printMsg(lvlError, format("@ substituter-failed %1% %2% %3%") + % storePath % status % e.msg()); + } + + /* Try the next substitute. */ + state = &SubstitutionGoal::tryNext; + worker.wakeUp(shared_from_this()); + return; + } + + canonicalisePathMetaData(destPath, -1); + + worker.store.optimisePath(destPath); // FIXME: combine with hashPath() + + if (repair) replaceValidPath(storePath, destPath); + + ValidPathInfo info2; + info2.path = storePath; + info2.hash = hash.first; + info2.narSize = hash.second; + info2.references = info.references; + info2.deriver = info.deriver; + worker.store.registerValidPath(info2); + + outputLock->setDeletion(true); + + worker.store.markContentsGood(storePath); + + printMsg(lvlChatty, + format("substitution of path `%1%' succeeded") % storePath); + + if (settings.printBuildTrace) + printMsg(lvlError, format("@ substituter-succeeded %1%") % storePath); + + amDone(ecSuccess); +} + + +void SubstitutionGoal::handleChildOutput(int fd, const string & data) +{ + assert(fd == logPipe.readSide); + if (verbosity >= settings.buildVerbosity) writeToStderr(data); + /* Don't write substitution output to a log file for now. We + probably should, though. */ +} + + +void SubstitutionGoal::handleEOF(int fd) +{ + if (fd == logPipe.readSide) worker.wakeUp(shared_from_this()); +} + + + +////////////////////////////////////////////////////////////////////// + + +static bool working = false; + + +Worker::Worker(LocalStore & store) + : store(store) +{ + /* Debugging: prevent recursive workers. */ + if (working) abort(); + working = true; + nrLocalBuilds = 0; + lastWokenUp = 0; + permanentFailure = false; +} + + +Worker::~Worker() +{ + working = false; + + /* Explicitly get rid of all strong pointers now. After this all + goals that refer to this worker should be gone. (Otherwise we + are in trouble, since goals may call childTerminated() etc. in + their destructors). */ + topGoals.clear(); +} + + +GoalPtr Worker::makeDerivationGoal(const Path & path, const StringSet & wantedOutputs, bool repair) +{ + GoalPtr goal = derivationGoals[path].lock(); + if (!goal) { + goal = GoalPtr(new DerivationGoal(path, wantedOutputs, *this, repair)); + derivationGoals[path] = goal; + wakeUp(goal); + } else + (dynamic_cast<DerivationGoal *>(goal.get()))->addWantedOutputs(wantedOutputs); + return goal; +} + + +GoalPtr Worker::makeSubstitutionGoal(const Path & path, bool repair) +{ + GoalPtr goal = substitutionGoals[path].lock(); + if (!goal) { + goal = GoalPtr(new SubstitutionGoal(path, *this, repair)); + substitutionGoals[path] = goal; + wakeUp(goal); + } + return goal; +} + + +static void removeGoal(GoalPtr goal, WeakGoalMap & goalMap) +{ + /* !!! inefficient */ + for (WeakGoalMap::iterator i = goalMap.begin(); + i != goalMap.end(); ) + if (i->second.lock() == goal) { + WeakGoalMap::iterator j = i; ++j; + goalMap.erase(i); + i = j; + } + else ++i; +} + + +void Worker::removeGoal(GoalPtr goal) +{ + nix::removeGoal(goal, derivationGoals); + nix::removeGoal(goal, substitutionGoals); + if (topGoals.find(goal) != topGoals.end()) { + topGoals.erase(goal); + /* If a top-level goal failed, then kill all other goals + (unless keepGoing was set). */ + if (goal->getExitCode() == Goal::ecFailed && !settings.keepGoing) + topGoals.clear(); + } + + /* Wake up goals waiting for any goal to finish. */ + foreach (WeakGoals::iterator, i, waitingForAnyGoal) { + GoalPtr goal = i->lock(); + if (goal) wakeUp(goal); + } + + waitingForAnyGoal.clear(); +} + + +void Worker::wakeUp(GoalPtr goal) +{ + goal->trace("woken up"); + awake.insert(goal); +} + + +unsigned Worker::getNrLocalBuilds() +{ + return nrLocalBuilds; +} + + +void Worker::childStarted(GoalPtr goal, + pid_t pid, const set<int> & fds, bool inBuildSlot, + bool respectTimeouts) +{ + Child child; + child.goal = goal; + child.fds = fds; + child.timeStarted = child.lastOutput = time(0); + child.inBuildSlot = inBuildSlot; + child.respectTimeouts = respectTimeouts; + children[pid] = child; + if (inBuildSlot) nrLocalBuilds++; +} + + +void Worker::childTerminated(pid_t pid, bool wakeSleepers) +{ + assert(pid != -1); /* common mistake */ + + Children::iterator i = children.find(pid); + assert(i != children.end()); + + if (i->second.inBuildSlot) { + assert(nrLocalBuilds > 0); + nrLocalBuilds--; + } + + children.erase(pid); + + if (wakeSleepers) { + + /* Wake up goals waiting for a build slot. */ + foreach (WeakGoals::iterator, i, wantingToBuild) { + GoalPtr goal = i->lock(); + if (goal) wakeUp(goal); + } + + wantingToBuild.clear(); + } +} + + +void Worker::waitForBuildSlot(GoalPtr goal) +{ + debug("wait for build slot"); + if (getNrLocalBuilds() < settings.maxBuildJobs) + wakeUp(goal); /* we can do it right away */ + else + wantingToBuild.insert(goal); +} + + +void Worker::waitForAnyGoal(GoalPtr goal) +{ + debug("wait for any goal"); + waitingForAnyGoal.insert(goal); +} + + +void Worker::waitForAWhile(GoalPtr goal) +{ + debug("wait for a while"); + waitingForAWhile.insert(goal); +} + + +void Worker::run(const Goals & _topGoals) +{ + foreach (Goals::iterator, i, _topGoals) topGoals.insert(*i); + + startNest(nest, lvlDebug, format("entered goal loop")); + + while (1) { + + checkInterrupt(); + + /* Call every wake goal. */ + while (!awake.empty() && !topGoals.empty()) { + WeakGoals awake2(awake); + awake.clear(); + foreach (WeakGoals::iterator, i, awake2) { + checkInterrupt(); + GoalPtr goal = i->lock(); + if (goal) goal->work(); + if (topGoals.empty()) break; + } + } + + if (topGoals.empty()) break; + + /* Wait for input. */ + if (!children.empty() || !waitingForAWhile.empty()) + waitForInput(); + else { + if (awake.empty() && settings.maxBuildJobs == 0) throw Error( + "unable to start any build; either increase `--max-jobs' " + "or enable distributed builds"); + assert(!awake.empty()); + } + } + + /* If --keep-going is not set, it's possible that the main goal + exited while some of its subgoals were still active. But if + --keep-going *is* set, then they must all be finished now. */ + assert(!settings.keepGoing || awake.empty()); + assert(!settings.keepGoing || wantingToBuild.empty()); + assert(!settings.keepGoing || children.empty()); +} + + +void Worker::waitForInput() +{ + printMsg(lvlVomit, "waiting for children"); + + /* Process output from the file descriptors attached to the + children, namely log output and output path creation commands. + We also use this to detect child termination: if we get EOF on + the logger pipe of a build, we assume that the builder has + terminated. */ + + bool useTimeout = false; + struct timeval timeout; + timeout.tv_usec = 0; + time_t before = time(0); + + /* If we're monitoring for silence on stdout/stderr, or if there + is a build timeout, then wait for input until the first + deadline for any child. */ + assert(sizeof(time_t) >= sizeof(long)); + time_t nearest = LONG_MAX; // nearest deadline + foreach (Children::iterator, i, children) { + if (!i->second.respectTimeouts) continue; + if (settings.maxSilentTime != 0) + nearest = std::min(nearest, i->second.lastOutput + settings.maxSilentTime); + if (settings.buildTimeout != 0) + nearest = std::min(nearest, i->second.timeStarted + settings.buildTimeout); + } + if (nearest != LONG_MAX) { + timeout.tv_sec = std::max((time_t) 1, nearest - before); + useTimeout = true; + printMsg(lvlVomit, format("sleeping %1% seconds") % timeout.tv_sec); + } + + /* If we are polling goals that are waiting for a lock, then wake + up after a few seconds at most. */ + if (!waitingForAWhile.empty()) { + useTimeout = true; + if (lastWokenUp == 0) + printMsg(lvlError, "waiting for locks or build slots..."); + if (lastWokenUp == 0 || lastWokenUp > before) lastWokenUp = before; + timeout.tv_sec = std::max((time_t) 1, (time_t) (lastWokenUp + settings.pollInterval - before)); + } else lastWokenUp = 0; + + using namespace std; + /* Use select() to wait for the input side of any logger pipe to + become `available'. Note that `available' (i.e., non-blocking) + includes EOF. */ + fd_set fds; + FD_ZERO(&fds); + int fdMax = 0; + foreach (Children::iterator, i, children) { + foreach (set<int>::iterator, j, i->second.fds) { + FD_SET(*j, &fds); + if (*j >= fdMax) fdMax = *j + 1; + } + } + + if (select(fdMax, &fds, 0, 0, useTimeout ? &timeout : 0) == -1) { + if (errno == EINTR) return; + throw SysError("waiting for input"); + } + + time_t after = time(0); + + /* Process all available file descriptors. */ + + /* Since goals may be canceled from inside the loop below (causing + them go be erased from the `children' map), we have to be + careful that we don't keep iterators alive across calls to + cancel(). */ + set<pid_t> pids; + foreach (Children::iterator, i, children) pids.insert(i->first); + + foreach (set<pid_t>::iterator, i, pids) { + checkInterrupt(); + Children::iterator j = children.find(*i); + if (j == children.end()) continue; // child destroyed + GoalPtr goal = j->second.goal.lock(); + assert(goal); + + set<int> fds2(j->second.fds); + foreach (set<int>::iterator, k, fds2) { + if (FD_ISSET(*k, &fds)) { + unsigned char buffer[4096]; + ssize_t rd = read(*k, buffer, sizeof(buffer)); + if (rd == -1) { + if (errno != EINTR) + throw SysError(format("reading from %1%") + % goal->getName()); + } else if (rd == 0) { + debug(format("%1%: got EOF") % goal->getName()); + goal->handleEOF(*k); + j->second.fds.erase(*k); + } else { + printMsg(lvlVomit, format("%1%: read %2% bytes") + % goal->getName() % rd); + string data((char *) buffer, rd); + goal->handleChildOutput(*k, data); + j->second.lastOutput = after; + } + } + } + + if (settings.maxSilentTime != 0 && + j->second.respectTimeouts && + after - j->second.lastOutput >= (time_t) settings.maxSilentTime) + { + printMsg(lvlError, + format("%1% timed out after %2% seconds of silence") + % goal->getName() % settings.maxSilentTime); + goal->cancel(true); + } + + if (settings.buildTimeout != 0 && + j->second.respectTimeouts && + after - j->second.timeStarted >= (time_t) settings.buildTimeout) + { + printMsg(lvlError, + format("%1% timed out after %2% seconds") + % goal->getName() % settings.buildTimeout); + goal->cancel(true); + } + } + + if (!waitingForAWhile.empty() && lastWokenUp + settings.pollInterval <= after) { + lastWokenUp = after; + foreach (WeakGoals::iterator, i, waitingForAWhile) { + GoalPtr goal = i->lock(); + if (goal) wakeUp(goal); + } + waitingForAWhile.clear(); + } +} + + +unsigned int Worker::exitStatus() +{ + return permanentFailure ? 100 : 1; +} + + +////////////////////////////////////////////////////////////////////// + + +void LocalStore::buildPaths(const PathSet & drvPaths, bool repair) +{ + startNest(nest, lvlDebug, + format("building %1%") % showPaths(drvPaths)); + + Worker worker(*this); + + Goals goals; + foreach (PathSet::const_iterator, i, drvPaths) { + DrvPathWithOutputs i2 = parseDrvPathWithOutputs(*i); + if (isDerivation(i2.first)) + goals.insert(worker.makeDerivationGoal(i2.first, i2.second, repair)); + else + goals.insert(worker.makeSubstitutionGoal(*i, repair)); + } + + worker.run(goals); + + PathSet failed; + foreach (Goals::iterator, i, goals) + if ((*i)->getExitCode() == Goal::ecFailed) { + DerivationGoal * i2 = dynamic_cast<DerivationGoal *>(i->get()); + if (i2) failed.insert(i2->getDrvPath()); + else failed.insert(dynamic_cast<SubstitutionGoal *>(i->get())->getStorePath()); + } + + if (!failed.empty()) + throw Error(format("build of %1% failed") % showPaths(failed), worker.exitStatus()); +} + + +void LocalStore::ensurePath(const Path & path) +{ + /* If the path is already valid, we're done. */ + if (isValidPath(path)) return; + + Worker worker(*this); + GoalPtr goal = worker.makeSubstitutionGoal(path); + Goals goals = singleton<Goals>(goal); + + worker.run(goals); + + if (goal->getExitCode() != Goal::ecSuccess) + throw Error(format("path `%1%' does not exist and cannot be created") % path, worker.exitStatus()); +} + + +void LocalStore::repairPath(const Path & path) +{ + Worker worker(*this); + GoalPtr goal = worker.makeSubstitutionGoal(path, true); + Goals goals = singleton<Goals>(goal); + + worker.run(goals); + + if (goal->getExitCode() != Goal::ecSuccess) + throw Error(format("cannot repair path `%1%'") % path, worker.exitStatus()); +} + + +} |