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NetBSD/bin/sh/eval.c
tron 9cae530b67 Revert revisions 1.91 and 1.92. The POSIX spec about the correct behaviour 
is contradictory at best. And these changes seem to cause more problems
that they are worth.
2008-05-26 14:55:17 +00:00

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/* $NetBSD: eval.c,v 1.93 2008/05/26 14:55:17 tron Exp $ */
/*-
* 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.
* 3. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95";
#else
__RCSID("$NetBSD: eval.c,v 1.93 2008/05/26 14:55:17 tron Exp $");
#endif
#endif /* not lint */
#include <stdbool.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/fcntl.h>
#include <sys/times.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/sysctl.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"
#include "main.h"
#ifndef SMALL
#include "myhistedit.h"
#endif
/* flags in argument to evaltree */
#define EV_EXIT 01 /* exit after evaluating tree */
#define EV_TESTED 02 /* exit status is checked; ignore -e flag */
#define EV_BACKCMD 04 /* command executing within back quotes */
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 */
const char *commandname;
struct strlist *cmdenviron;
int exitstatus; /* exit status of last command */
int back_exitstatus; /* exit status of backquoted command */
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 expredir(union node *);
STATIC void evalpipe(union node *);
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;
}
SHELLPROC {
exitstatus = 0;
}
#endif
static int
sh_pipe(int fds[2])
{
int nfd;
if (pipe(fds))
return -1;
if (fds[0] < 3) {
nfd = fcntl(fds[0], F_DUPFD, 3);
if (nfd != -1) {
close(fds[0]);
fds[0] = nfd;
}
}
if (fds[1] < 3) {
nfd = fcntl(fds[1], F_DUPFD, 3);
if (nfd != -1) {
close(fds[1]);
fds[1] = nfd;
}
}
return 0;
}
/*
* The eval commmand.
*/
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 (;;) {
while (*p)
STPUTC(*p++, concat);
if ((p = *ap++) == NULL)
break;
STPUTC(' ', concat);
}
STPUTC('\0', concat);
p = grabstackstr(concat);
}
evalstring(p, EV_TESTED);
}
return exitstatus;
}
/*
* Execute a command or commands contained in a string.
*/
void
evalstring(char *s, int flag)
{
union node *n;
struct stackmark smark;
setstackmark(&smark);
setinputstring(s, 1);
while ((n = parsecmd(0)) != NEOF) {
evaltree(n, flag);
popstackmark(&smark);
}
popfile();
popstackmark(&smark);
}
/*
* Evaluate a parse tree. The value is left in the global variable
* exitstatus.
*/
void
evaltree(union node *n, int flags)
{
bool do_etest;
do_etest = false;
if (n == NULL) {
TRACE(("evaltree(NULL) called\n"));
exitstatus = 0;
goto out;
}
#ifndef SMALL
displayhist = 1; /* show history substitutions done with fc */
#endif
TRACE(("pid %d, evaltree(%p: %d, %d) called\n",
getpid(), n, n->type, flags));
switch (n->type) {
case NSEMI:
evaltree(n->nbinary.ch1, flags & EV_TESTED);
if (evalskip)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NAND:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus != 0)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NOR:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus == 0)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NREDIR:
expredir(n->nredir.redirect);
redirect(n->nredir.redirect, REDIR_PUSH);
evaltree(n->nredir.n, flags);
popredir();
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)
evaltree(n->nif.ifpart, flags);
else if (n->nif.elsepart)
evaltree(n->nif.elsepart, flags);
else
exitstatus = 0;
break;
}
case NWHILE:
case NUNTIL:
evalloop(n, flags);
break;
case NFOR:
evalfor(n, flags);
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;
}
out:
if (pendingsigs)
dotrap();
if ((flags & EV_EXIT) != 0 || (eflag && exitstatus != 0 && do_etest))
exitshell(exitstatus);
}
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;
break;
}
if (n->type == NWHILE) {
if (exitstatus != 0)
break;
} else {
if (exitstatus == 0)
break;
}
evaltree(n->nbinary.ch2, flags & EV_TESTED);
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;
int status = 0;
setstackmark(&smark);
arglist.lastp = &arglist.list;
for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
if (evalskip)
goto out;
}
*arglist.lastp = NULL;
loopnest++;
for (sp = arglist.list ; sp ; sp = sp->next) {
setvar(n->nfor.var, sp->text, 0);
evaltree(n->nfor.body, flags & EV_TESTED);
status = exitstatus;
if (evalskip) {
if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = 0;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = 0;
break;
}
}
loopnest--;
exitstatus = status;
out:
popstackmark(&smark);
}
STATIC void
evalcase(union node *n, int flags)
{
union node *cp;
union node *patp;
struct arglist arglist;
struct stackmark smark;
int status = 0;
setstackmark(&smark);
arglist.lastp = &arglist.list;
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);
status = exitstatus;
}
goto out;
}
}
}
out:
exitstatus = status;
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);
expredir(n->nredir.redirect);
INTOFF;
jp = makejob(n, 1);
if (forkshell(jp, n, backgnd ? FORK_BG : FORK_FG) == 0) {
INTON;
if (backgnd)
flags &=~ EV_TESTED;
redirect(n->nredir.redirect, 0);
/* never returns */
evaltree(n->nredir.n, flags | EV_EXIT);
}
if (! backgnd)
exitstatus = waitforjob(jp);
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 NFROMTO:
case NFROM:
case NTO:
case NCLOBBER:
case NAPPEND:
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_FULL | EXP_TILDE);
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(0x%lx) called\n", (long)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 (sh_pipe(pip) < 0) {
if (prevfd >= 0)
close(prevfd);
error("Pipe call failed");
}
}
if (forkshell(jp, lp->n, n->npipe.backgnd ? FORK_BG : FORK_FG) == 0) {
INTON;
if (prevfd > 0) {
close(0);
copyfd(prevfd, 0);
close(prevfd);
}
if (pip[1] >= 0) {
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
}
evaltree(lp->n, EV_EXIT);
}
if (prevfd >= 0)
close(prevfd);
prevfd = pip[0];
close(pip[1]);
}
if (n->npipe.backgnd == 0) {
exitstatus = waitforjob(jp);
TRACE(("evalpipe: job done exit status %d\n", exitstatus));
}
INTON;
}
/*
* 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 */
setstackmark(&smark);
result->fd = -1;
result->buf = NULL;
result->nleft = 0;
result->jp = NULL;
if (n == NULL) {
goto out;
}
#ifdef notyet
/*
* For now we disable executing builtins in the same
* context as the shell, because we are not keeping
* enough state to recover from changes that are
* supposed only to affect subshells. eg. echo "`cd /`"
*/
if (n->type == NCMD) {
exitstatus = oexitstatus;
evalcommand(n, EV_BACKCMD, result);
} else
#endif
{
INTOFF;
if (sh_pipe(pip) < 0)
error("Pipe call failed");
jp = makejob(n, 1);
if (forkshell(jp, n, FORK_NOJOB) == 0) {
FORCEINTON;
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
eflag = 0;
evaltree(n, EV_EXIT);
/* NOTREACHED */
}
close(pip[1]);
result->fd = pip[0];
result->jp = jp;
INTON;
}
out:
popstackmark(&smark);
TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n",
result->fd, result->buf, result->nleft, result->jp));
}
static const char *
syspath(void)
{
static char *sys_path = NULL;
static int mib[] = {CTL_USER, USER_CS_PATH};
static char def_path[] = "PATH=/usr/bin:/bin:/usr/sbin:/sbin";
size_t len;
if (sys_path == NULL) {
if (sysctl(mib, 2, 0, &len, 0, 0) != -1 &&
(sys_path = ckmalloc(len + 5)) != NULL &&
sysctl(mib, 2, sys_path + 5, &len, 0, 0) != -1) {
memcpy(sys_path, "PATH=", 5);
} else {
ckfree(sys_path);
/* something to keep things happy */
sys_path = def_path;
}
}
return sys_path;
}
static int
parse_command_args(int argc, char **argv, int *use_syspath)
{
int sv_argc = argc;
char *cp, c;
*use_syspath = 0;
for (;;) {
argv++;
if (--argc == 0)
break;
cp = *argv;
if (*cp++ != '-')
break;
if (*cp == '-' && cp[1] == 0) {
argv++;
argc--;
break;
}
while ((c = *cp++)) {
switch (c) {
case 'p':
*use_syspath = 1;
break;
default:
/* run 'typecmd' for other options */
return 0;
}
}
}
return sv_argc - argc;
}
int vforked = 0;
/*
* Execute a simple command.
*/
STATIC void
evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
{
struct stackmark smark;
union node *argp;
struct arglist arglist;
struct arglist varlist;
volatile int flags = flgs;
char ** volatile argv;
volatile int argc;
char **envp;
int varflag;
struct strlist *sp;
volatile int mode;
int pip[2];
struct cmdentry cmdentry;
struct job * volatile jp;
struct jmploc jmploc;
struct jmploc *volatile savehandler = NULL;
const char *volatile savecmdname;
volatile struct shparam saveparam;
struct localvar *volatile savelocalvars;
volatile int e;
char * volatile lastarg;
const char * volatile path = pathval();
volatile int temp_path;
vforked = 0;
/* First expand the arguments. */
TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
setstackmark(&smark);
back_exitstatus = 0;
arglist.lastp = &arglist.list;
varflag = 1;
/* Expand arguments, ignoring the initial 'name=value' ones */
for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
char *p = argp->narg.text;
if (varflag && is_name(*p)) {
do {
p++;
} while (is_in_name(*p));
if (*p == '=')
continue;
}
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
varflag = 0;
}
*arglist.lastp = NULL;
expredir(cmd->ncmd.redirect);
/* Now do the initial 'name=value' ones we skipped above */
varlist.lastp = &varlist.list;
for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
char *p = argp->narg.text;
if (!is_name(*p))
break;
do
p++;
while (is_in_name(*p));
if (*p != '=')
break;
expandarg(argp, &varlist, EXP_VARTILDE);
}
*varlist.lastp = NULL;
argc = 0;
for (sp = arglist.list ; sp ; sp = sp->next)
argc++;
argv = stalloc(sizeof (char *) * (argc + 1));
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;
out2str(ps4val());
for (sp = varlist.list ; sp ; sp = sp->next) {
if (sep != 0)
outc(sep, &errout);
out2str(sp->text);
sep = ' ';
}
for (sp = arglist.list ; sp ; sp = sp->next) {
if (sep != 0)
outc(sep, &errout);
out2str(sp->text);
sep = ' ';
}
outc('\n', &errout);
flushout(&errout);
}
/* Now locate the command. */
if (argc == 0) {
cmdentry.cmdtype = CMDSPLBLTIN;
cmdentry.u.bltin = bltincmd;
} else {
static const char PATH[] = "PATH=";
int cmd_flags = DO_ERR;
/*
* 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;
do {
int argsused, use_syspath;
find_command(argv[0], &cmdentry, cmd_flags, path);
if (cmdentry.cmdtype == CMDUNKNOWN) {
exitstatus = 127;
flushout(&errout);
goto out;
}
/* implement the 'command' builtin here */
if (cmdentry.cmdtype != CMDBUILTIN ||
cmdentry.u.bltin != bltincmd)
break;
cmd_flags |= DO_NOFUNC;
argsused = parse_command_args(argc, argv, &use_syspath);
if (argsused == 0) {
/* use 'type' builting to display info */
cmdentry.u.bltin = typecmd;
break;
}
argc -= argsused;
argv += argsused;
if (use_syspath)
path = syspath() + 5;
} while (argc != 0);
if (cmdentry.cmdtype == CMDSPLBLTIN && cmd_flags & DO_NOFUNC)
/* posix mandates that 'command <splbltin>' act as if
<splbltin> was a normal builtin */
cmdentry.cmdtype = CMDBUILTIN;
}
/* Fork off a child process if necessary. */
if (cmd->ncmd.backgnd
|| (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0)
|| ((flags & EV_BACKCMD) != 0
&& ((cmdentry.cmdtype != CMDBUILTIN && cmdentry.cmdtype != CMDSPLBLTIN)
|| cmdentry.u.bltin == dotcmd
|| cmdentry.u.bltin == evalcmd))) {
INTOFF;
jp = makejob(cmd, 1);
mode = cmd->ncmd.backgnd;
if (flags & EV_BACKCMD) {
mode = FORK_NOJOB;
if (sh_pipe(pip) < 0)
error("Pipe call failed");
}
#ifdef DO_SHAREDVFORK
/* It is essential that if DO_SHAREDVFORK is defined that the
* child's address space is actually shared with the parent as
* we rely on this.
*/
if (cmdentry.cmdtype == CMDNORMAL) {
pid_t pid;
savelocalvars = localvars;
localvars = NULL;
vforked = 1;
switch (pid = vfork()) {
case -1:
TRACE(("Vfork failed, errno=%d\n", errno));
INTON;
error("Cannot vfork");
break;
case 0:
/* Make sure that exceptions only unwind to
* after the vfork(2)
*/
if (setjmp(jmploc.loc)) {
if (exception == EXSHELLPROC) {
/* We can't progress with the vfork,
* so, set vforked = 2 so the parent
* knows, and _exit();
*/
vforked = 2;
_exit(0);
} else {
_exit(exerrno);
}
}
savehandler = handler;
handler = &jmploc;
listmklocal(varlist.list, VEXPORT | VNOFUNC);
forkchild(jp, cmd, mode, vforked);
break;
default:
handler = savehandler; /* restore from vfork(2) */
poplocalvars();
localvars = savelocalvars;
if (vforked == 2) {
vforked = 0;
(void)waitpid(pid, NULL, 0);
/* We need to progress in a normal fork fashion */
goto normal_fork;
}
vforked = 0;
forkparent(jp, cmd, mode, pid);
goto parent;
}
} else {
normal_fork:
#endif
if (forkshell(jp, cmd, mode) != 0)
goto parent; /* at end of routine */
FORCEINTON;
#ifdef DO_SHAREDVFORK
}
#endif
if (flags & EV_BACKCMD) {
if (!vforked) {
FORCEINTON;
}
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
}
flags |= EV_EXIT;
}
/* This is the child process if a fork occurred. */
/* Execute the command. */
switch (cmdentry.cmdtype) {
case CMDFUNCTION:
#ifdef DEBUG
trputs("Shell function: "); trargs(argv);
#endif
redirect(cmd->ncmd.redirect, REDIR_PUSH);
saveparam = shellparam;
shellparam.malloc = 0;
shellparam.reset = 1;
shellparam.nparam = argc - 1;
shellparam.p = argv + 1;
shellparam.optnext = NULL;
INTOFF;
savelocalvars = localvars;
localvars = NULL;
INTON;
if (setjmp(jmploc.loc)) {
if (exception == EXSHELLPROC) {
freeparam((volatile struct shparam *)
&saveparam);
} else {
freeparam(&shellparam);
shellparam = saveparam;
}
poplocalvars();
localvars = savelocalvars;
handler = savehandler;
longjmp(handler->loc, 1);
}
savehandler = handler;
handler = &jmploc;
listmklocal(varlist.list, 0);
/* stop shell blowing its stack */
if (++funcnest > 1000)
error("too many nested function calls");
evaltree(cmdentry.u.func, flags & EV_TESTED);
funcnest--;
INTOFF;
poplocalvars();
localvars = savelocalvars;
freeparam(&shellparam);
shellparam = saveparam;
handler = savehandler;
popredir();
INTON;
if (evalskip == SKIPFUNC) {
evalskip = 0;
skipcount = 0;
}
if (flags & EV_EXIT)
exitshell(exitstatus);
break;
case CMDBUILTIN:
case CMDSPLBLTIN:
#ifdef DEBUG
trputs("builtin command: "); trargs(argv);
#endif
mode = (cmdentry.u.bltin == execcmd) ? 0 : REDIR_PUSH;
if (flags == EV_BACKCMD) {
memout.nleft = 0;
memout.nextc = memout.buf;
memout.bufsize = 64;
mode |= REDIR_BACKQ;
}
e = -1;
savehandler = handler;
savecmdname = commandname;
handler = &jmploc;
if (!setjmp(jmploc.loc)) {
/* We need to ensure the command hash table isn't
* corruped by temporary PATH assignments.
* However we must ensure the 'local' command works!
*/
if (path != pathval() && (cmdentry.u.bltin == hashcmd ||
cmdentry.u.bltin == typecmd)) {
savelocalvars = localvars;
localvars = 0;
mklocal(path - 5 /* PATH= */, 0);
temp_path = 1;
} else
temp_path = 0;
redirect(cmd->ncmd.redirect, mode);
/* exec is a special builtin, but needs this list... */
cmdenviron = varlist.list;
/* we must check 'readonly' flag for all builtins */
listsetvar(varlist.list,
cmdentry.cmdtype == CMDSPLBLTIN ? 0 : VNOSET);
commandname = argv[0];
/* initialize nextopt */
argptr = argv + 1;
optptr = NULL;
/* and getopt */
optreset = 1;
optind = 1;
exitstatus = cmdentry.u.bltin(argc, argv);
} else {
e = exception;
exitstatus = e == EXINT ? SIGINT + 128 :
e == EXEXEC ? exerrno : 2;
}
handler = savehandler;
flushall();
out1 = &output;
out2 = &errout;
freestdout();
if (temp_path) {
poplocalvars();
localvars = savelocalvars;
}
cmdenviron = NULL;
if (e != EXSHELLPROC) {
commandname = savecmdname;
if (flags & EV_EXIT)
exitshell(exitstatus);
}
if (e != -1) {
if ((e != EXERROR && e != EXEXEC)
|| cmdentry.cmdtype == CMDSPLBLTIN)
exraise(e);
FORCEINTON;
}
if (cmdentry.u.bltin != execcmd)
popredir();
if (flags == EV_BACKCMD) {
backcmd->buf = memout.buf;
backcmd->nleft = memout.nextc - memout.buf;
memout.buf = NULL;
}
break;
default:
#ifdef DEBUG
trputs("normal command: "); trargs(argv);
#endif
clearredir(vforked);
redirect(cmd->ncmd.redirect, vforked ? REDIR_VFORK : 0);
if (!vforked)
for (sp = varlist.list ; sp ; sp = sp->next)
setvareq(sp->text, VEXPORT|VSTACK);
envp = environment();
shellexec(argv, envp, path, cmdentry.u.index, vforked);
break;
}
goto out;
parent: /* parent process gets here (if we forked) */
if (mode == FORK_FG) { /* argument to fork */
exitstatus = waitforjob(jp);
} else if (mode == FORK_NOJOB) {
backcmd->fd = pip[0];
close(pip[1]);
backcmd->jp = jp;
}
FORCEINTON;
out:
if (lastarg)
/* dsl: I think this is intended to be used to support
* '_' in 'vi' command mode during line editing...
* However I implemented that within libedit itself.
*/
setvar("_", lastarg, 0);
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.
*/
int
bltincmd(int argc, char **argv)
{
/*
* Preserve exitstatus of a previous possible redirection
* as POSIX mandates
*/
return back_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 return command.
*/
int
returncmd(int argc, char **argv)
{
int ret = argc > 1 ? number(argv[1]) : exitstatus;
if (funcnest) {
evalskip = SKIPFUNC;
skipcount = 1;
return ret;
}
else {
/* Do what ksh does; skip the rest of the file */
evalskip = SKIPFILE;
skipcount = 1;
return ret;
}
}
int
falsecmd(int argc, char **argv)
{
return 1;
}
int
truecmd(int argc, char **argv)
{
return 0;
}
int
execcmd(int argc, char **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, 0);
}
return 0;
}
static int
conv_time(clock_t ticks, char *seconds, size_t l)
{
static clock_t tpm = 0;
clock_t mins;
int i;
if (!tpm)
tpm = sysconf(_SC_CLK_TCK) * 60;
mins = ticks / tpm;
snprintf(seconds, l, "%.4f", (ticks - mins * tpm) * 60.0 / tpm );
if (seconds[0] == '6' && seconds[1] == '0') {
/* 59.99995 got rounded up... */
mins++;
strlcpy(seconds, "0.0", l);
return mins;
}
/* suppress trailing zeros */
i = strlen(seconds) - 1;
for (; seconds[i] == '0' && seconds[i - 1] != '.'; i--)
seconds[i] = 0;
return mins;
}
int
timescmd(int argc, char **argv)
{
struct tms tms;
int u, s, cu, cs;
char us[8], ss[8], cus[8], css[8];
nextopt("");
times(&tms);
u = conv_time(tms.tms_utime, us, sizeof(us));
s = conv_time(tms.tms_stime, ss, sizeof(ss));
cu = conv_time(tms.tms_cutime, cus, sizeof(cus));
cs = conv_time(tms.tms_cstime, css, sizeof(css));
outfmt(out1, "%dm%ss %dm%ss\n%dm%ss %dm%ss\n",
u, us, s, ss, cu, cus, cs, css);
return 0;
}
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