diff options
Diffstat (limited to 'src/libstore')
| -rw-r--r-- | src/libstore/build.cc | 123 |
1 files changed, 85 insertions, 38 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 31b2876ab015..a86fa0f947a0 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -123,10 +123,10 @@ public: return exitCode; } - void cancel() - { - amDone(ecFailed); - } + /* 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() = 0; protected: void amDone(ExitCode result); @@ -592,6 +592,8 @@ public: DerivationGoal(const Path & drvPath, Worker & worker); ~DerivationGoal(); + void cancel(); + void work(); Path getDrvPath() @@ -646,6 +648,9 @@ private: /* Return the set of (in)valid paths. */ PathSet checkPathValidity(bool returnValid); + + /* Forcibly kill the child process, if any. */ + void killChild(); }; @@ -664,36 +669,48 @@ DerivationGoal::~DerivationGoal() /* Careful: we should never ever throw an exception from a destructor. */ try { - if (pid != -1) { - worker.childTerminated(pid); - - if (buildUser.enabled()) { - /* Note that we can't let pid's destructor kill the - the child process, since it may not have the - appropriate privilege (i.e., the setuid helper - should do it). - - However, 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); - assert(pid == -1); - } - } - + killChild(); deleteTmpDir(false); - } catch (Error & e) { printMsg(lvlError, format("error (ignored): %1%") % e.msg()); } } +void DerivationGoal::killChild() +{ + if (pid != -1) { + worker.childTerminated(pid); + + if (buildUser.enabled()) { + /* We can't use pid.kill(), since we may not have the + appropriate privilege. I.e., if we're not root, then + setuid helper should do it). + + Also, 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); + } +} + + +void DerivationGoal::cancel() +{ + killChild(); + amDone(ecFailed); +} + + void DerivationGoal::work() { (this->*state)(); @@ -1813,6 +1830,8 @@ public: SubstitutionGoal(const Path & storePath, Worker & worker); ~SubstitutionGoal(); + void cancel(); + void work(); /* The states. */ @@ -1840,10 +1859,24 @@ SubstitutionGoal::SubstitutionGoal(const Path & storePath, Worker & worker) SubstitutionGoal::~SubstitutionGoal() { + /* !!! Once we let substitution goals run under a build user, we + need to do use the setuid helper just as in ~DerivationGoal(). + Idem for cancel. */ if (pid != -1) worker.childTerminated(pid); } +void SubstitutionGoal::cancel() +{ + if (pid != -1) { + pid_t savedPid = pid; + pid.kill(); + worker.childTerminated(savedPid); + } + amDone(ecFailed); +} + + void SubstitutionGoal::work() { (this->*state)(); @@ -2189,6 +2222,8 @@ void Worker::childStarted(GoalPtr goal, void Worker::childTerminated(pid_t pid, bool wakeSleepers) { + assert(pid != -1); /* common mistake */ + Children::iterator i = children.find(pid); assert(i != children.end()); @@ -2329,38 +2364,50 @@ void Worker::waitForInput() time_t now = 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; for (Children::iterator i = children.begin(); i != children.end(); ++i) + pids.insert(i->first); + + for (set<pid_t>::iterator i = pids.begin(); + i != pids.end(); ++i) { checkInterrupt(); - GoalPtr goal = i->second.goal.lock(); + Children::iterator j = children.find(*i); + if (j == children.end()) continue; // child destroyed + GoalPtr goal = j->second.goal.lock(); assert(goal); - - set<int> fds2(i->second.fds); - for (set<int>::iterator j = fds2.begin(); j != fds2.end(); ++j) { - if (FD_ISSET(*j, &fds)) { + + set<int> fds2(j->second.fds); + for (set<int>::iterator k = fds2.begin(); k != fds2.end(); ++k) { + if (FD_ISSET(*k, &fds)) { unsigned char buffer[4096]; - ssize_t rd = read(*j, buffer, sizeof(buffer)); + 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(*j); - i->second.fds.erase(*j); + 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(*j, data); - i->second.lastOutput = now; + goal->handleChildOutput(*k, data); + j->second.lastOutput = now; } } } if (maxSilentTime != 0 && - now - i->second.lastOutput >= (time_t) maxSilentTime) + now - j->second.lastOutput >= (time_t) maxSilentTime) { printMsg(lvlError, format("%1% timed out after %2% seconds of silence") |