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00d33feb9d
freebsd-skq/bin/sh/eval.c
jilles 00d33feb9d sh: Reduce unnecessary forks with eval. 
The eval special builtin now runs the code with EV_EXIT if it was run
with EV_EXIT itself.

In particular, this eliminates one fork when a command substitution contains
an eval command that ends with an external program or a subshell.

This is similar to what r220978 did for functions.
2011-06-16 21:50:28 +00:00

1277 lines
28 KiB
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/*-
* Copyright (c) 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <paths.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/resource.h>
#include <sys/wait.h> /* For WIFSIGNALED(status) */
#include <errno.h>
/*
* Evaluate a command.
*/
#include "shell.h"
#include "nodes.h"
#include "syntax.h"
#include "expand.h"
#include "parser.h"
#include "jobs.h"
#include "eval.h"
#include "builtins.h"
#include "options.h"
#include "exec.h"
#include "redir.h"
#include "input.h"
#include "output.h"
#include "trap.h"
#include "var.h"
#include "memalloc.h"
#include "error.h"
#include "show.h"
#include "mystring.h"
#ifndef NO_HISTORY
#include "myhistedit.h"
#endif
int evalskip; /* set if we are skipping commands */
static int skipcount; /* number of levels to skip */
MKINIT int loopnest; /* current loop nesting level */
int funcnest; /* depth of function calls */
static int builtin_flags; /* evalcommand flags for builtins */
char *commandname;
struct strlist *cmdenviron;
int exitstatus; /* exit status of last command */
int oexitstatus; /* saved exit status */
static void evalloop(union node *, int);
static void evalfor(union node *, int);
static void evalcase(union node *, int);
static void evalsubshell(union node *, int);
static void evalredir(union node *, int);
static void expredir(union node *);
static void evalpipe(union node *);
static int is_valid_fast_cmdsubst(union node *n);
static void evalcommand(union node *, int, struct backcmd *);
static void prehash(union node *);
/*
* Called to reset things after an exception.
*/
#ifdef mkinit
INCLUDE "eval.h"
RESET {
evalskip = 0;
loopnest = 0;
funcnest = 0;
}
#endif
/*
* The eval command.
*/
int
evalcmd(int argc, char **argv)
{
char *p;
char *concat;
char **ap;
if (argc > 1) {
p = argv[1];
if (argc > 2) {
STARTSTACKSTR(concat);
ap = argv + 2;
for (;;) {
STPUTS(p, concat);
if ((p = *ap++) == NULL)
break;
STPUTC(' ', concat);
}
STPUTC('\0', concat);
p = grabstackstr(concat);
}
evalstring(p, builtin_flags);
} else
exitstatus = 0;
return exitstatus;
}
/*
* Execute a command or commands contained in a string.
*/
void
evalstring(char *s, int flags)
{
union node *n;
struct stackmark smark;
int flags_exit;
int any;
flags_exit = flags & EV_EXIT;
flags &= ~EV_EXIT;
any = 0;
setstackmark(&smark);
setinputstring(s, 1);
while ((n = parsecmd(0)) != NEOF) {
if (n != NULL && !nflag) {
if (flags_exit && preadateof())
evaltree(n, flags | EV_EXIT);
else
evaltree(n, flags);
any = 1;
}
popstackmark(&smark);
}
popfile();
popstackmark(&smark);
if (!any)
exitstatus = 0;
if (flags_exit)
exraise(EXEXIT);
}
/*
* Evaluate a parse tree. The value is left in the global variable
* exitstatus.
*/
void
evaltree(union node *n, int flags)
{
int do_etest;
union node *next;
do_etest = 0;
if (n == NULL) {
TRACE(("evaltree(NULL) called\n"));
exitstatus = 0;
goto out;
}
do {
next = NULL;
#ifndef NO_HISTORY
displayhist = 1; /* show history substitutions done with fc */
#endif
TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
switch (n->type) {
case NSEMI:
evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
if (evalskip)
goto out;
next = n->nbinary.ch2;
break;
case NAND:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus != 0) {
goto out;
}
next = n->nbinary.ch2;
break;
case NOR:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus == 0)
goto out;
next = n->nbinary.ch2;
break;
case NREDIR:
evalredir(n, flags);
break;
case NSUBSHELL:
evalsubshell(n, flags);
do_etest = !(flags & EV_TESTED);
break;
case NBACKGND:
evalsubshell(n, flags);
break;
case NIF: {
evaltree(n->nif.test, EV_TESTED);
if (evalskip)
goto out;
if (exitstatus == 0)
next = n->nif.ifpart;
else if (n->nif.elsepart)
next = n->nif.elsepart;
else
exitstatus = 0;
break;
}
case NWHILE:
case NUNTIL:
evalloop(n, flags & ~EV_EXIT);
break;
case NFOR:
evalfor(n, flags & ~EV_EXIT);
break;
case NCASE:
evalcase(n, flags);
break;
case NDEFUN:
defun(n->narg.text, n->narg.next);
exitstatus = 0;
break;
case NNOT:
evaltree(n->nnot.com, EV_TESTED);
exitstatus = !exitstatus;
break;
case NPIPE:
evalpipe(n);
do_etest = !(flags & EV_TESTED);
break;
case NCMD:
evalcommand(n, flags, (struct backcmd *)NULL);
do_etest = !(flags & EV_TESTED);
break;
default:
out1fmt("Node type = %d\n", n->type);
flushout(&output);
break;
}
n = next;
} while (n != NULL);
out:
if (pendingsigs)
dotrap();
if (eflag && exitstatus != 0 && do_etest)
exitshell(exitstatus);
if (flags & EV_EXIT)
exraise(EXEXIT);
}
static void
evalloop(union node *n, int flags)
{
int status;
loopnest++;
status = 0;
for (;;) {
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip) {
skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = 0;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = 0;
if (evalskip == SKIPFUNC || evalskip == SKIPFILE)
status = exitstatus;
break;
}
if (n->type == NWHILE) {
if (exitstatus != 0)
break;
} else {
if (exitstatus == 0)
break;
}
evaltree(n->nbinary.ch2, flags);
status = exitstatus;
if (evalskip)
goto skipping;
}
loopnest--;
exitstatus = status;
}
static void
evalfor(union node *n, int flags)
{
struct arglist arglist;
union node *argp;
struct strlist *sp;
struct stackmark smark;
setstackmark(&smark);
arglist.lastp = &arglist.list;
for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
oexitstatus = exitstatus;
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
if (evalskip)
goto out;
}
*arglist.lastp = NULL;
exitstatus = 0;
loopnest++;
for (sp = arglist.list ; sp ; sp = sp->next) {
setvar(n->nfor.var, sp->text, 0);
evaltree(n->nfor.body, flags);
if (evalskip) {
if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = 0;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = 0;
break;
}
}
loopnest--;
out:
popstackmark(&smark);
}
static void
evalcase(union node *n, int flags)
{
union node *cp;
union node *patp;
struct arglist arglist;
struct stackmark smark;
setstackmark(&smark);
arglist.lastp = &arglist.list;
oexitstatus = exitstatus;
exitstatus = 0;
expandarg(n->ncase.expr, &arglist, EXP_TILDE);
for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
if (casematch(patp, arglist.list->text)) {
if (evalskip == 0) {
evaltree(cp->nclist.body, flags);
}
goto out;
}
}
}
out:
popstackmark(&smark);
}
/*
* Kick off a subshell to evaluate a tree.
*/
static void
evalsubshell(union node *n, int flags)
{
struct job *jp;
int backgnd = (n->type == NBACKGND);
oexitstatus = exitstatus;
expredir(n->nredir.redirect);
if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
if (backgnd)
flags &=~ EV_TESTED;
redirect(n->nredir.redirect, 0);
evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
} else if (! backgnd) {
INTOFF;
exitstatus = waitforjob(jp, (int *)NULL);
INTON;
} else
exitstatus = 0;
}
/*
* Evaluate a redirected compound command.
*/
static void
evalredir(union node *n, int flags)
{
struct jmploc jmploc;
struct jmploc *savehandler;
volatile int in_redirect = 1;
oexitstatus = exitstatus;
expredir(n->nredir.redirect);
savehandler = handler;
if (setjmp(jmploc.loc)) {
int e;
handler = savehandler;
e = exception;
popredir();
if (e == EXERROR || e == EXEXEC) {
if (in_redirect) {
exitstatus = 2;
return;
}
}
longjmp(handler->loc, 1);
} else {
INTOFF;
handler = &jmploc;
redirect(n->nredir.redirect, REDIR_PUSH);
in_redirect = 0;
INTON;
evaltree(n->nredir.n, flags);
}
INTOFF;
handler = savehandler;
popredir();
INTON;
}
/*
* Compute the names of the files in a redirection list.
*/
static void
expredir(union node *n)
{
union node *redir;
for (redir = n ; redir ; redir = redir->nfile.next) {
struct arglist fn;
fn.lastp = &fn.list;
switch (redir->type) {
case NFROM:
case NTO:
case NFROMTO:
case NAPPEND:
case NCLOBBER:
expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
redir->nfile.expfname = fn.list->text;
break;
case NFROMFD:
case NTOFD:
if (redir->ndup.vname) {
expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
fixredir(redir, fn.list->text, 1);
}
break;
}
}
}
/*
* Evaluate a pipeline. All the processes in the pipeline are children
* of the process creating the pipeline. (This differs from some versions
* of the shell, which make the last process in a pipeline the parent
* of all the rest.)
*/
static void
evalpipe(union node *n)
{
struct job *jp;
struct nodelist *lp;
int pipelen;
int prevfd;
int pip[2];
TRACE(("evalpipe(%p) called\n", (void *)n));
pipelen = 0;
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
pipelen++;
INTOFF;
jp = makejob(n, pipelen);
prevfd = -1;
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
prehash(lp->n);
pip[1] = -1;
if (lp->next) {
if (pipe(pip) < 0) {
close(prevfd);
error("Pipe call failed: %s", strerror(errno));
}
}
if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
INTON;
if (prevfd > 0) {
dup2(prevfd, 0);
close(prevfd);
}
if (pip[1] >= 0) {
if (!(prevfd >= 0 && pip[0] == 0))
close(pip[0]);
if (pip[1] != 1) {
dup2(pip[1], 1);
close(pip[1]);
}
}
evaltree(lp->n, EV_EXIT);
}
if (prevfd >= 0)
close(prevfd);
prevfd = pip[0];
if (pip[1] != -1)
close(pip[1]);
}
INTON;
if (n->npipe.backgnd == 0) {
INTOFF;
exitstatus = waitforjob(jp, (int *)NULL);
TRACE(("evalpipe: job done exit status %d\n", exitstatus));
INTON;
} else
exitstatus = 0;
}
static int
is_valid_fast_cmdsubst(union node *n)
{
return (n->type == NCMD);
}
/*
* Execute a command inside back quotes. If it's a builtin command, we
* want to save its output in a block obtained from malloc. Otherwise
* we fork off a subprocess and get the output of the command via a pipe.
* Should be called with interrupts off.
*/
void
evalbackcmd(union node *n, struct backcmd *result)
{
int pip[2];
struct job *jp;
struct stackmark smark; /* unnecessary */
struct jmploc jmploc;
struct jmploc *savehandler;
struct localvar *savelocalvars;
setstackmark(&smark);
result->fd = -1;
result->buf = NULL;
result->nleft = 0;
result->jp = NULL;
if (n == NULL) {
exitstatus = 0;
goto out;
}
if (is_valid_fast_cmdsubst(n)) {
exitstatus = oexitstatus;
savelocalvars = localvars;
localvars = NULL;
forcelocal++;
savehandler = handler;
if (setjmp(jmploc.loc)) {
if (exception == EXERROR || exception == EXEXEC)
exitstatus = 2;
else if (exception != 0) {
handler = savehandler;
forcelocal--;
poplocalvars();
localvars = savelocalvars;
longjmp(handler->loc, 1);
}
} else {
handler = &jmploc;
evalcommand(n, EV_BACKCMD, result);
}
handler = savehandler;
forcelocal--;
poplocalvars();
localvars = savelocalvars;
} else {
exitstatus = 0;
if (pipe(pip) < 0)
error("Pipe call failed: %s", strerror(errno));
jp = makejob(n, 1);
if (forkshell(jp, n, FORK_NOJOB) == 0) {
FORCEINTON;
close(pip[0]);
if (pip[1] != 1) {
dup2(pip[1], 1);
close(pip[1]);
}
evaltree(n, EV_EXIT);
}
close(pip[1]);
result->fd = pip[0];
result->jp = jp;
}
out:
popstackmark(&smark);
TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
result->fd, result->buf, result->nleft, result->jp));
}
/*
* Check if a builtin can safely be executed in the same process,
* even though it should be in a subshell (command substitution).
* Note that jobid, jobs, times and trap can show information not
* available in a child process; this is deliberate.
* The arguments should already have been expanded.
*/
static int
safe_builtin(int idx, int argc, char **argv)
{
if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD ||
idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD ||
idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD ||
idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD ||
idx == TYPECMD)
return (1);
if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
idx == UMASKCMD)
return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
if (idx == SETCMD)
return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
argv[1][0] == '+') && argv[1][1] == 'o' &&
argv[1][2] == '\0'));
return (0);
}
/*
* Execute a simple command.
* Note: This may or may not return if (flags & EV_EXIT).
*/
static void
evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
{
struct stackmark smark;
union node *argp;
struct arglist arglist;
struct arglist varlist;
char **argv;
int argc;
char **envp;
int varflag;
struct strlist *sp;
int mode;
int pip[2];
struct cmdentry cmdentry;
struct job *jp;
struct jmploc jmploc;
struct jmploc *savehandler;
char *savecmdname;
struct shparam saveparam;
struct localvar *savelocalvars;
struct parsefile *savetopfile;
volatile int e;
char *lastarg;
int realstatus;
int do_clearcmdentry;
const char *path = pathval();
/* First expand the arguments. */
TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
setstackmark(&smark);
arglist.lastp = &arglist.list;
varlist.lastp = &varlist.list;
varflag = 1;
jp = NULL;
do_clearcmdentry = 0;
oexitstatus = exitstatus;
exitstatus = 0;
for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
if (varflag && isassignment(argp->narg.text)) {
expandarg(argp, &varlist, EXP_VARTILDE);
continue;
}
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
varflag = 0;
}
*arglist.lastp = NULL;
*varlist.lastp = NULL;
expredir(cmd->ncmd.redirect);
argc = 0;
for (sp = arglist.list ; sp ; sp = sp->next)
argc++;
/* Add one slot at the beginning for tryexec(). */
argv = stalloc(sizeof (char *) * (argc + 2));
argv++;
for (sp = arglist.list ; sp ; sp = sp->next) {
TRACE(("evalcommand arg: %s\n", sp->text));
*argv++ = sp->text;
}
*argv = NULL;
lastarg = NULL;
if (iflag && funcnest == 0 && argc > 0)
lastarg = argv[-1];
argv -= argc;
/* Print the command if xflag is set. */
if (xflag) {
char sep = 0;
const char *p, *ps4;
ps4 = expandstr(ps4val());
out2str(ps4 != NULL ? ps4 : ps4val());
for (sp = varlist.list ; sp ; sp = sp->next) {
if (sep != 0)
out2c(' ');
p = strchr(sp->text, '=');
if (p != NULL) {
p++;
outbin(sp->text, p - sp->text, out2);
out2qstr(p);
} else
out2qstr(sp->text);
sep = ' ';
}
for (sp = arglist.list ; sp ; sp = sp->next) {
if (sep != 0)
out2c(' ');
/* Disambiguate command looking like assignment. */
if (sp == arglist.list &&
strchr(sp->text, '=') != NULL &&
strchr(sp->text, '\'') == NULL) {
out2c('\'');
out2str(sp->text);
out2c('\'');
} else
out2qstr(sp->text);
sep = ' ';
}
out2c('\n');
flushout(&errout);
}
/* Now locate the command. */
if (argc == 0) {
/* Variable assignment(s) without command */
cmdentry.cmdtype = CMDBUILTIN;
cmdentry.u.index = BLTINCMD;
cmdentry.special = 0;
} else {
static const char PATH[] = "PATH=";
int cmd_flags = 0, bltinonly = 0;
/*
* Modify the command lookup path, if a PATH= assignment
* is present
*/
for (sp = varlist.list ; sp ; sp = sp->next)
if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
path = sp->text + sizeof(PATH) - 1;
/*
* On `PATH=... command`, we need to make
* sure that the command isn't using the
* non-updated hash table of the outer PATH
* setting and we need to make sure that
* the hash table isn't filled with items
* from the temporary setting.
*
* It would be better to forbit using and
* updating the table while this command
* runs, by the command finding mechanism
* is heavily integrated with hash handling,
* so we just delete the hash before and after
* the command runs. Partly deleting like
* changepatch() does doesn't seem worth the
* bookinging effort, since most such runs add
* directories in front of the new PATH.
*/
clearcmdentry();
do_clearcmdentry = 1;
}
for (;;) {
if (bltinonly) {
cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
if (cmdentry.u.index < 0) {
cmdentry.u.index = BLTINCMD;
argv--;
argc++;
break;
}
} else
find_command(argv[0], &cmdentry, cmd_flags, path);
/* implement the bltin and command builtins here */
if (cmdentry.cmdtype != CMDBUILTIN)
break;
if (cmdentry.u.index == BLTINCMD) {
if (argc == 1)
break;
argv++;
argc--;
bltinonly = 1;
} else if (cmdentry.u.index == COMMANDCMD) {
if (argc == 1)
break;
if (!strcmp(argv[1], "-p")) {
if (argc == 2)
break;
if (argv[2][0] == '-') {
if (strcmp(argv[2], "--"))
break;
if (argc == 3)
break;
argv += 3;
argc -= 3;
} else {
argv += 2;
argc -= 2;
}
path = _PATH_STDPATH;
clearcmdentry();
do_clearcmdentry = 1;
} else if (!strcmp(argv[1], "--")) {
if (argc == 2)
break;
argv += 2;
argc -= 2;
} else if (argv[1][0] == '-')
break;
else {
argv++;
argc--;
}
cmd_flags |= DO_NOFUNC;
bltinonly = 0;
} else
break;
}
/*
* Special builtins lose their special properties when
* called via 'command'.
*/
if (cmd_flags & DO_NOFUNC)
cmdentry.special = 0;
}
/* Fork off a child process if necessary. */
if (cmd->ncmd.backgnd
|| ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
&& ((flags & EV_EXIT) == 0 || have_traps()))
|| ((flags & EV_BACKCMD) != 0
&& (cmdentry.cmdtype != CMDBUILTIN ||
!safe_builtin(cmdentry.u.index, argc, argv)))) {
jp = makejob(cmd, 1);
mode = cmd->ncmd.backgnd;
if (flags & EV_BACKCMD) {
mode = FORK_NOJOB;
if (pipe(pip) < 0)
error("Pipe call failed: %s", strerror(errno));
}
if (forkshell(jp, cmd, mode) != 0)
goto parent; /* at end of routine */
if (flags & EV_BACKCMD) {
FORCEINTON;
close(pip[0]);
if (pip[1] != 1) {
dup2(pip[1], 1);
close(pip[1]);
}
flags &= ~EV_BACKCMD;
}
flags |= EV_EXIT;
}
/* This is the child process if a fork occurred. */
/* Execute the command. */
if (cmdentry.cmdtype == CMDFUNCTION) {
#ifdef DEBUG
trputs("Shell function: "); trargs(argv);
#endif
saveparam = shellparam;
shellparam.malloc = 0;
shellparam.reset = 1;
shellparam.nparam = argc - 1;
shellparam.p = argv + 1;
shellparam.optnext = NULL;
INTOFF;
savelocalvars = localvars;
localvars = NULL;
reffunc(cmdentry.u.func);
savehandler = handler;
if (setjmp(jmploc.loc)) {
freeparam(&shellparam);
shellparam = saveparam;
popredir();
unreffunc(cmdentry.u.func);
poplocalvars();
localvars = savelocalvars;
funcnest--;
handler = savehandler;
longjmp(handler->loc, 1);
}
handler = &jmploc;
funcnest++;
redirect(cmd->ncmd.redirect, REDIR_PUSH);
INTON;
for (sp = varlist.list ; sp ; sp = sp->next)
mklocal(sp->text);
exitstatus = oexitstatus;
evaltree(getfuncnode(cmdentry.u.func),
flags & (EV_TESTED | EV_EXIT));
INTOFF;
unreffunc(cmdentry.u.func);
poplocalvars();
localvars = savelocalvars;
freeparam(&shellparam);
shellparam = saveparam;
handler = savehandler;
funcnest--;
popredir();
INTON;
if (evalskip == SKIPFUNC) {
evalskip = 0;
skipcount = 0;
}
if (jp)
exitshell(exitstatus);
} else if (cmdentry.cmdtype == CMDBUILTIN) {
#ifdef DEBUG
trputs("builtin command: "); trargs(argv);
#endif
mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
if (flags == EV_BACKCMD) {
memout.nleft = 0;
memout.nextc = memout.buf;
memout.bufsize = 64;
mode |= REDIR_BACKQ;
cmdentry.special = 0;
}
savecmdname = commandname;
savetopfile = getcurrentfile();
cmdenviron = varlist.list;
e = -1;
savehandler = handler;
if (setjmp(jmploc.loc)) {
e = exception;
if (e == EXINT)
exitstatus = SIGINT+128;
else if (e != EXEXIT)
exitstatus = 2;
goto cmddone;
}
handler = &jmploc;
redirect(cmd->ncmd.redirect, mode);
/*
* If there is no command word, redirection errors should
* not be fatal but assignment errors should.
*/
if (argc == 0 && !(flags & EV_BACKCMD))
cmdentry.special = 1;
listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
if (argc > 0)
bltinsetlocale();
commandname = argv[0];
argptr = argv + 1;
nextopt_optptr = NULL; /* initialize nextopt */
builtin_flags = flags;
exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
flushall();
cmddone:
if (argc > 0)
bltinunsetlocale();
cmdenviron = NULL;
out1 = &output;
out2 = &errout;
freestdout();
handler = savehandler;
commandname = savecmdname;
if (jp)
exitshell(exitstatus);
if (flags == EV_BACKCMD) {
backcmd->buf = memout.buf;
backcmd->nleft = memout.nextc - memout.buf;
memout.buf = NULL;
}
if (cmdentry.u.index != EXECCMD)
popredir();
if (e != -1) {
if ((e != EXERROR && e != EXEXEC)
|| cmdentry.special)
exraise(e);
popfilesupto(savetopfile);
if (flags != EV_BACKCMD)
FORCEINTON;
}
} else {
#ifdef DEBUG
trputs("normal command: "); trargs(argv);
#endif
redirect(cmd->ncmd.redirect, 0);
for (sp = varlist.list ; sp ; sp = sp->next)
setvareq(sp->text, VEXPORT|VSTACK);
envp = environment();
shellexec(argv, envp, path, cmdentry.u.index);
/*NOTREACHED*/
}
goto out;
parent: /* parent process gets here (if we forked) */
if (mode == FORK_FG) { /* argument to fork */
INTOFF;
exitstatus = waitforjob(jp, &realstatus);
INTON;
if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
evalskip = SKIPBREAK;
skipcount = loopnest;
}
} else if (mode == FORK_NOJOB) {
backcmd->fd = pip[0];
close(pip[1]);
backcmd->jp = jp;
} else
exitstatus = 0;
out:
if (lastarg)
setvar("_", lastarg, 0);
if (do_clearcmdentry)
clearcmdentry();
popstackmark(&smark);
}
/*
* Search for a command. This is called before we fork so that the
* location of the command will be available in the parent as well as
* the child. The check for "goodname" is an overly conservative
* check that the name will not be subject to expansion.
*/
static void
prehash(union node *n)
{
struct cmdentry entry;
if (n && n->type == NCMD && n->ncmd.args)
if (goodname(n->ncmd.args->narg.text))
find_command(n->ncmd.args->narg.text, &entry, 0,
pathval());
}
/*
* Builtin commands. Builtin commands whose functions are closely
* tied to evaluation are implemented here.
*/
/*
* No command given, a bltin command with no arguments, or a bltin command
* with an invalid name.
*/
int
bltincmd(int argc, char **argv)
{
if (argc > 1) {
out2fmt_flush("%s: not found\n", argv[1]);
return 127;
}
/*
* Preserve exitstatus of a previous possible redirection
* as POSIX mandates
*/
return exitstatus;
}
/*
* Handle break and continue commands. Break, continue, and return are
* all handled by setting the evalskip flag. The evaluation routines
* above all check this flag, and if it is set they start skipping
* commands rather than executing them. The variable skipcount is
* the number of loops to break/continue, or the number of function
* levels to return. (The latter is always 1.) It should probably
* be an error to break out of more loops than exist, but it isn't
* in the standard shell so we don't make it one here.
*/
int
breakcmd(int argc, char **argv)
{
int n = argc > 1 ? number(argv[1]) : 1;
if (n > loopnest)
n = loopnest;
if (n > 0) {
evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
skipcount = n;
}
return 0;
}
/*
* The `command' command.
*/
int
commandcmd(int argc, char **argv)
{
const char *path;
int ch;
int cmd = -1;
path = bltinlookup("PATH", 1);
optind = optreset = 1;
opterr = 0;
while ((ch = getopt(argc, argv, "pvV")) != -1) {
switch (ch) {
case 'p':
path = _PATH_STDPATH;
break;
case 'v':
cmd = TYPECMD_SMALLV;
break;
case 'V':
cmd = TYPECMD_BIGV;
break;
case '?':
default:
error("unknown option: -%c", optopt);
}
}
argc -= optind;
argv += optind;
if (cmd != -1) {
if (argc != 1)
error("wrong number of arguments");
return typecmd_impl(2, argv - 1, cmd, path);
}
if (argc != 0)
error("commandcmd bad call");
/*
* Do nothing successfully if no command was specified;
* ksh also does this.
*/
return 0;
}
/*
* The return command.
*/
int
returncmd(int argc, char **argv)
{
int ret = argc > 1 ? number(argv[1]) : oexitstatus;
if (funcnest) {
evalskip = SKIPFUNC;
skipcount = 1;
} else {
/* skip the rest of the file */
evalskip = SKIPFILE;
skipcount = 1;
}
return ret;
}
int
falsecmd(int argc __unused, char **argv __unused)
{
return 1;
}
int
truecmd(int argc __unused, char **argv __unused)
{
return 0;
}
int
execcmd(int argc, char **argv)
{
/*
* Because we have historically not supported any options,
* only treat "--" specially.
*/
if (argc > 1 && strcmp(argv[1], "--") == 0)
argc--, argv++;
if (argc > 1) {
struct strlist *sp;
iflag = 0; /* exit on error */
mflag = 0;
optschanged();
for (sp = cmdenviron; sp ; sp = sp->next)
setvareq(sp->text, VEXPORT|VSTACK);
shellexec(argv + 1, environment(), pathval(), 0);
}
return 0;
}
int
timescmd(int argc __unused, char **argv __unused)
{
struct rusage ru;
long shumins, shsmins, chumins, chsmins;
double shusecs, shssecs, chusecs, chssecs;
if (getrusage(RUSAGE_SELF, &ru) < 0)
return 1;
shumins = ru.ru_utime.tv_sec / 60;
shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
shsmins = ru.ru_stime.tv_sec / 60;
shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
return 1;
chumins = ru.ru_utime.tv_sec / 60;
chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
chsmins = ru.ru_stime.tv_sec / 60;
chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
return 0;
}
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