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freebsd/bin/sh/jobs.h
Jilles Tjoelker ed4c3b5f86 sh: Forget about terminated background processes sooner.
Unless $! has been referenced for a particular job or $! still contains that
job's pid, forget about it after it has terminated. If $! has been
referenced, remember the job until the wait builtin has reported its
completion (either with the pid as parameter or without parameters).

In interactive mode, jobs are forgotten after termination has been reported,
which happens before primary prompts and through the jobs builtin. Even
then, though, remember a job if $! has been referenced.

This is similar to what is suggested by POSIX and should fix most memory
leaks (which also tend to cause sh to use more CPU time) with long running
scripts that start background jobs.

Caveats:
* Repeatedly referencing $! without ever doing 'wait', like
    while :; do foo & echo started foo: $!; sleep 60; done
  will still use a lot of memory and CPU time in the long run.
* The jobs and jobid builtins do not cause a job to be remembered for longer
  like expanding $! does.

PR:		bin/55346
2010-06-29 22:37:45 +00:00

108 lines
3.8 KiB
C

/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)jobs.h 8.2 (Berkeley) 5/4/95
* $FreeBSD$
*/
/* Mode argument to forkshell. Don't change FORK_FG or FORK_BG. */
#define FORK_FG 0
#define FORK_BG 1
#define FORK_NOJOB 2
#include <signal.h> /* for sig_atomic_t */
/*
* A job structure contains information about a job. A job is either a
* single process or a set of processes contained in a pipeline. In the
* latter case, pidlist will be non-NULL, and will point to a -1 terminated
* array of pids.
*/
struct procstat {
pid_t pid; /* process id */
int status; /* status flags (defined above) */
char *cmd; /* text of command being run */
};
/* states */
#define JOBSTOPPED 1 /* all procs are stopped */
#define JOBDONE 2 /* all procs are completed */
struct job {
struct procstat ps0; /* status of process */
struct procstat *ps; /* status or processes when more than one */
short nprocs; /* number of processes */
pid_t pgrp; /* process group of this job */
char state; /* true if job is finished */
char used; /* true if this entry is in used */
char changed; /* true if status has changed */
char foreground; /* true if running in the foreground */
char remembered; /* true if $! referenced */
#if JOBS
char jobctl; /* job running under job control */
struct job *next; /* job used after this one */
#endif
};
enum {
SHOWJOBS_DEFAULT, /* job number, status, command */
SHOWJOBS_VERBOSE, /* job number, PID, status, command */
SHOWJOBS_PIDS, /* PID only */
SHOWJOBS_PGIDS /* PID of the group leader only */
};
extern int job_warning; /* user was warned about stopped jobs */
extern int in_waitcmd; /* are we in waitcmd()? */
extern int in_dowait; /* are we in dowait()? */
extern volatile sig_atomic_t breakwaitcmd; /* break wait to process traps? */
void setjobctl(int);
int fgcmd(int, char **);
int bgcmd(int, char **);
int jobscmd(int, char **);
void showjobs(int, int);
int waitcmd(int, char **);
int jobidcmd(int, char **);
struct job *makejob(union node *, int);
pid_t forkshell(struct job *, union node *, int);
int waitforjob(struct job *, int *);
int stoppedjobs(void);
int backgndpidset(void);
pid_t backgndpidval(void);
char *commandtext(union node *);
#if ! JOBS
#define setjobctl(on) /* do nothing */
#endif