diff options
| -rw-r--r-- | src/libstore/build.cc | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 47d0979213ba..f0b136d06132 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -312,6 +312,50 @@ const char * * strings2CharPtrs(const Strings & ss) } +static void killUser(uid_t uid) +{ + debug(format("killing all processes running under uid `%1%'") % uid); + + assert(uid != rootUserId); /* just to be safe... */ + + /* The system call kill(-1, sig) sends the signal `sig' to all + users to which the current process can send signals. So we + fork a process, switch to uid, and send a mass kill. */ + + Pid pid; + pid = fork(); + switch (pid) { + + case -1: + throw SysError("unable to fork"); + + case 0: + try { /* child */ + + if (setuid(uid) == -1) abort(); + + if (kill(-1, SIGKILL) == -1) + throw SysError(format("cannot kill processes for UID `%1%'") % uid); + + } catch (exception & e) { + cerr << format("build error: %1%\n") % e.what(); + _exit(1); + } + _exit(0); + } + + /* parent */ + if (pid.wait(true) != 0) + throw Error(format("cannot kill processes for UID `%1%'") % uid); + + /* !!! We should really do some check to make sure that there are + no processes left running under `uid', but there is no portable + way to do so (I think). The most reliable way may be `ps -eo + uid | grep -q $uid'. */ +} + + + ////////////////////////////////////////////////////////////////////// @@ -1075,6 +1119,10 @@ void DerivationGoal::startBuilder() getuid() == rootUserId) { buildUser = allocBuildUser(); + + /* Make sure that no other processes are executing under this + uid. */ + killUser(buildUser); /* Change ownership of the temporary build directory. !!! gid */ if (chown(tmpDir.c_str(), buildUser, (gid_t) -1) == -1) |