diff options
Diffstat (limited to 'Src/exec.c')
| -rw-r--r-- | Src/exec.c | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/Src/exec.c b/Src/exec.c index 21270c82d..0755d55cd 100644 --- a/Src/exec.c +++ b/Src/exec.c @@ -1652,7 +1652,13 @@ execpline(Estate state, wordcode slcode, int how, int last1) int synch[2]; struct timeval bgtime; + /* + * A pipeline with the shell handling the right + * hand side was stopped. We'll fork to allow + * it to continue. + */ if (pipe(synch) < 0 || (pid = zfork(&bgtime)) == -1) { + /* Failure */ if (pid < 0) { close(synch[0]); close(synch[1]); @@ -1666,6 +1672,18 @@ execpline(Estate state, wordcode slcode, int how, int last1) thisjob = newjob; } else if (pid) { + /* + * Parent: job control is here. If the job + * started for the RHS of the pipeline is still + * around, then its a SUBJOB and the job for + * earlier parts of the pipeeline is its SUPERJOB. + * The newly forked shell isn't recorded as a + * separate job here, just as list_pipe_pid. + * If the superjob exits (it may already have + * done so, see child branch below), we'll use + * list_pipe_pid to form the basis of a + * replacement job --- see SUBLEADER code above. + */ char dummy; lpforked = @@ -1692,9 +1710,33 @@ execpline(Estate state, wordcode slcode, int how, int last1) break; } else { + Job pjn = jobtab + list_pipe_job; close(synch[0]); entersubsh(ESUB_ASYNC); - if (jobtab[list_pipe_job].procs) { + /* + * At this point, we used to attach this process + * to the process group of list_pipe_job (the + * new superjob) any time that was still available. + * That caused problems when the fork happened + * early enough that the subjob is in that + * process group, since then we will stop this + * job when we signal the subjob, and we have + * no way here to know that we shouldn't also + * send STOP to itself, resulting in two stops. + * So don't do that if the original + * list_pipe_job has exited. + * + * The choice here needs to match the assumption + * made when handling SUBLEADER above that the + * process group is our own PID. I'm not sure + * if there's a potential race for that. But + * setting up a new process group if the + * superjob is still functioning seems the wrong + * thing to do. + */ + if (pjn->procs && + (pjn->stat & STAT_INUSE) && + !(pjn->stat & STAT_DONE)) { if (setpgrp(0L, mypgrp = jobtab[list_pipe_job].gleader) == -1) { setpgrp(0L, mypgrp = getpid()); |