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.
132 lines
4.4 KiB
C
132 lines
4.4 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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* @(#)var.h 8.2 (Berkeley) 5/4/95
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* $FreeBSD$
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*/
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/*
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* Shell variables.
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*/
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/* flags */
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#define VEXPORT 0x01 /* variable is exported */
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#define VREADONLY 0x02 /* variable cannot be modified */
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#define VSTRFIXED 0x04 /* variable struct is statically allocated */
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#define VTEXTFIXED 0x08 /* text is statically allocated */
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#define VSTACK 0x10 /* text is allocated on the stack */
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#define VUNSET 0x20 /* the variable is not set */
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#define VNOFUNC 0x40 /* don't call the callback function */
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#define VNOSET 0x80 /* do not set variable - just readonly test */
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#define VNOLOCAL 0x100 /* ignore forcelocal */
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struct var {
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struct var *next; /* next entry in hash list */
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int flags; /* flags are defined above */
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int name_len; /* length of name */
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char *text; /* name=value */
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void (*func)(const char *);
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/* function to be called when */
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/* the variable gets set/unset */
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};
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struct localvar {
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struct localvar *next; /* next local variable in list */
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struct var *vp; /* the variable that was made local */
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int flags; /* saved flags */
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char *text; /* saved text */
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};
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struct localvar *localvars;
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extern int forcelocal;
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extern struct var vifs;
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extern struct var vmail;
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extern struct var vmpath;
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extern struct var vpath;
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extern struct var vppid;
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extern struct var vps1;
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extern struct var vps2;
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extern struct var vps4;
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extern struct var vdisvfork;
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#ifndef NO_HISTORY
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extern struct var vhistsize;
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extern struct var vterm;
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#endif
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extern int localeisutf8;
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/* The parser uses the locale that was in effect at startup. */
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extern int initial_localeisutf8;
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/*
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* The following macros access the values of the above variables.
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* They have to skip over the name. They return the null string
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* for unset variables.
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*/
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#define ifsval() (vifs.text + 4)
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#define ifsset() ((vifs.flags & VUNSET) == 0)
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#define mailval() (vmail.text + 5)
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#define mpathval() (vmpath.text + 9)
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#define pathval() (vpath.text + 5)
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#define ps1val() (vps1.text + 4)
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#define ps2val() (vps2.text + 4)
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#define ps4val() (vps4.text + 4)
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#define optindval() (voptind.text + 7)
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#ifndef NO_HISTORY
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#define histsizeval() (vhistsize.text + 9)
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#define termval() (vterm.text + 5)
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#endif
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#define mpathset() ((vmpath.flags & VUNSET) == 0)
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#define disvforkset() ((vdisvfork.flags & VUNSET) == 0)
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void initvar(void);
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void setvar(const char *, const char *, int);
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void setvareq(char *, int);
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struct strlist;
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void listsetvar(struct strlist *, int);
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char *lookupvar(const char *);
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char *bltinlookup(const char *, int);
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void bltinsetlocale(void);
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void bltinunsetlocale(void);
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void updatecharset(void);
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void initcharset(void);
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char **environment(void);
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int showvarscmd(int, char **);
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void mklocal(char *);
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void poplocalvars(void);
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int unsetvar(const char *);
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int setvarsafe(const char *, const char *, int);
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