diff options
Diffstat (limited to 'job.c')
| -rw-r--r-- | job.c | 127 |
1 files changed, 58 insertions, 69 deletions
@@ -299,21 +299,30 @@ vmsWaitForChildren(int *status) #endif -/* Count the number of dead children we have. If we can use wait3() or - waitpid() then we'll never use this count: it's completely unnecessary. - But we need the handler installed to interrupt the select() call for - the jobs pipe, so we might as well keep it. */ +/* Handle a dead child. This handler may or may not ever be installed. + + If we're using the jobserver blocking read, we need it. First, installing + it ensures the read will interrupt on SIGCHLD. Second, we close the dup'd + read side of the pipe to ensure we don't enter another blocking read + without reaping all the dead children. In this case we don't need the + dead_children count. + + If we don't have either waitpid or wait3, then make is unreliable, but we + use the dead_children count to reap children as best we can. In this case + job_rfd will never be >= 0. */ static unsigned int dead_children = 0; -/* Notice that a child died. - reap_children should be called when convenient. */ RETSIGTYPE child_handler (sig) int sig; { ++dead_children; + if (job_rfd >= 0) + close (job_rfd); + job_rfd = -1; + if (debug_flag) printf (_("Got a SIGCHLD; %u unreaped children.\n"), dead_children); } @@ -927,12 +936,7 @@ start_job_command (child) /* Set the descriptor to close on exec, so it does not litter any child's descriptor table. When it is dup2'd onto descriptor 0, that descriptor will not close on exec. */ -#ifdef F_SETFD -#ifndef FD_CLOEXEC -#define FD_CLOEXEC 1 -#endif - (void) fcntl (bad_stdin, F_SETFD, FD_CLOEXEC); -#endif + CLOSE_ON_EXEC (bad_stdin); } } @@ -1170,57 +1174,6 @@ start_waiting_job (c) /* If not, start it locally. */ if (!c->remote) { -#ifdef MAKE_JOBSERVER - /* If we are controlling multiple jobs, and we don't yet have one, - * obtain a token before starting the child. */ - if (job_fds[0] >= 0) - { - while (c->job_token == '-') - /* If the reserved token is available, just use that. */ - if (my_job_token != '-') - { - c->job_token = my_job_token; - my_job_token = '-'; - } - /* Read a token. We set the non-blocking bit on this earlier, so - if there's no token to be read we'll return immediately. */ - else if (read (job_fds[0], &c->job_token, 1) < 1) - { - fd_set rfds; - int r; - - FD_ZERO(&rfds); - FD_SET(job_fds[0], &rfds); - - /* The select blocks until (a) there's data to read, in which - case we come back around and try to grab the token before - someone else does, or (b) a signal (SIGCHLD), is reported - (because we installed a handler for it). If the latter, - call reap_children() to try to free up some slots. */ - - r = select (job_fds[0]+1, SELECT_FD_SET_CAST &rfds, - NULL, NULL, NULL); - - if (r < 0) - { -#ifdef EINTR - if (errno != EINTR) - /* We should definitely handle this more gracefully! - What kinds of things can happen here? ^C closes the - pipe? Something else closes it? */ - pfatal_with_name (_("read jobs pipe")); -#endif - /* We were interrupted; handle any dead children. */ - reap_children (1, 0); - } - } - - assert(c->job_token != '-'); - if (debug_flag) - printf (_("Obtained token `%c' for child 0x%08lx (%s).\n"), - c->job_token, (unsigned long int) c, c->file->name); - } -#endif /* If we are running at least one job already and the load average is too high, make this one wait. */ if (job_slots_used > 0 && load_too_high ()) @@ -1291,12 +1244,6 @@ new_job (file) /* Chop the commands up into lines if they aren't already. */ chop_commands (cmds); - /* Wait for a job slot to be freed up. If we allow an infinite number - don't bother; also job_slots will == 0 if we're using the job pipe. */ - if (job_slots != 0) - while (job_slots_used == job_slots) - reap_children (1, 0); - /* Expand the command lines and store the results in LINES. */ lines = (char **) xmalloc (cmds->ncommand_lines * sizeof (char *)); for (i = 0; i < cmds->ncommand_lines; ++i) @@ -1413,6 +1360,48 @@ new_job (file) /* Fetch the first command line to be run. */ job_next_command (c); + /* Wait for a job slot to be freed up. If we allow an infinite number + don't bother; also job_slots will == 0 if we're using the jobserver. */ + if (job_slots != 0) + while (job_slots_used == job_slots) + reap_children (1, 0); +#ifdef MAKE_JOBSERVER + /* If we are controlling multiple jobs, and we don't yet have one, + obtain a token before starting the child. */ + else if (job_fds[0] >= 0) + { + while (c->job_token == '-') + /* If the reserved token is available, just use that. */ + if (my_job_token == '+') + { + c->job_token = my_job_token; + my_job_token = '-'; + } + /* Read a token. As long as there's no token available we'll block. + If we get a SIGCHLD we'll return with EINTR. If one happened + before we got here we'll return with EBADF. */ + else if (read (job_rfd, &c->job_token, 1) < 1) + { + if (errno == EINTR) + ; + + /* If EBADF, we got a SIGCHLD before. Otherwise, who knows? */ + else if (errno != EBADF) + pfatal_with_name (_("read jobs pipe")); + + /* Something's done; reap it. We don't force a block here; if + something strange happened and nothing's ready, just come back + and wait some more. */ + reap_children (0, 0); + } + + assert(c->job_token != '-'); + if (debug_flag) + printf (_("Obtained token `%c' for child 0x%08lx (%s).\n"), + c->job_token, (unsigned long int) c, c->file->name); + } +#endif + /* The job is now primed. Start it running. (This will notice if there are in fact no commands.) */ (void)start_waiting_job (c); |