caf29fab8c
This uses vfork() for simple commands and command substitutions containing a single simple command, invoking an external program under certain conditions (no redirections or variable assignments, non-interactive shell, no job control). These restrictions limit the amount of code executed in a vforked child. There is a large speedup (for example 35%) in microbenchmarks. The difference in buildkernel is smaller (for example 0.5%) but still statistically significant. See http://lists.freebsd.org/pipermail/freebsd-hackers/2012-January/037581.html for some numbers. The use of vfork() can be disabled by setting a variable named SH_DISABLE_VFORK.
104 lines
3.8 KiB
C
104 lines
3.8 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Kenneth Almquist.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)jobs.h 8.2 (Berkeley) 5/4/95
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* $FreeBSD$
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*/
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/* Mode argument to forkshell. Don't change FORK_FG or FORK_BG. */
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#define FORK_FG 0
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#define FORK_BG 1
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#define FORK_NOJOB 2
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#include <signal.h> /* for sig_atomic_t */
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/*
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* A job structure contains information about a job. A job is either a
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* single process or a set of processes contained in a pipeline. In the
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* latter case, pidlist will be non-NULL, and will point to a -1 terminated
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* array of pids.
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*/
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struct procstat {
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pid_t pid; /* process id */
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int status; /* status flags (defined above) */
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char *cmd; /* text of command being run */
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};
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/* states */
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#define JOBSTOPPED 1 /* all procs are stopped */
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#define JOBDONE 2 /* all procs are completed */
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struct job {
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struct procstat ps0; /* status of process */
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struct procstat *ps; /* status or processes when more than one */
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short nprocs; /* number of processes */
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pid_t pgrp; /* process group of this job */
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char state; /* true if job is finished */
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char used; /* true if this entry is in used */
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char changed; /* true if status has changed */
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char foreground; /* true if running in the foreground */
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char remembered; /* true if $! referenced */
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#if JOBS
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char jobctl; /* job running under job control */
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struct job *next; /* job used after this one */
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#endif
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};
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enum {
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SHOWJOBS_DEFAULT, /* job number, status, command */
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SHOWJOBS_VERBOSE, /* job number, PID, status, command */
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SHOWJOBS_PIDS, /* PID only */
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SHOWJOBS_PGIDS /* PID of the group leader only */
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};
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extern int job_warning; /* user was warned about stopped jobs */
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extern int in_waitcmd; /* are we in waitcmd()? */
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extern int in_dowait; /* are we in dowait()? */
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extern volatile sig_atomic_t breakwaitcmd; /* break wait to process traps? */
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void setjobctl(int);
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void showjobs(int, int);
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struct job *makejob(union node *, int);
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pid_t forkshell(struct job *, union node *, int);
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pid_t vforkexecshell(struct job *, char **, char **, const char *, int, int []);
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int waitforjob(struct job *, int *);
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int stoppedjobs(void);
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int backgndpidset(void);
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pid_t backgndpidval(void);
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char *commandtext(union node *);
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#if ! JOBS
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#define setjobctl(on) /* do nothing */
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#endif
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