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NetBSD/bin/sh/eval.c

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/* $NetBSD: eval.c,v 1.153 2017/11/19 03:23:01 kre 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 1.153 2017/11/19 03:23:01 kre Exp $");
#endif
#endif /* not lint */
#include <stdbool.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <sys/fcntl.h>
#include <sys/stat.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 "nodenames.h"
#include "myhistedit.h"
#endif
STATIC enum skipstate evalskip; /* != SKIPNONE if we are skipping commands */
STATIC int skipcount; /* number of levels to skip */
STATIC int loopnest; /* current loop nesting level */
STATIC int funcnest; /* depth of function calls */
STATIC int builtin_flags; /* evalcommand flags for builtins */
/*
* Base function nesting level inside a dot command. Set to 0 initially
* and to (funcnest + 1) before every dot command to enable
* 1) detection of being in a file sourced by a dot command and
* 2) counting of function nesting in that file for the implementation
* of the return command.
* The value is reset to its previous value after the dot command.
*/
STATIC int dot_funcnest;
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 *);
STATIC char *find_dot_file(char *);
/*
* Called to reset things after an exception.
*/
#ifdef mkinit
INCLUDE "eval.h"
RESET {
reset_eval();
}
SHELLPROC {
exitstatus = 0;
}
#endif
void
reset_eval(void)
{
evalskip = SKIPNONE;
dot_funcnest = 0;
loopnest = 0;
funcnest = 0;
}
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, builtin_flags & EV_TESTED);
} else
exitstatus = 0;
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, line_number);
while ((n = parsecmd(0)) != NEOF) {
XTRACE(DBG_EVAL, ("evalstring: "), showtree(n));
if (n && nflag == 0)
evaltree(n, flag | EV_MORE);
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;
int sflags = flags & ~EV_EXIT;
do_etest = false;
if (n == NULL || nflag) {
VTRACE(DBG_EVAL, ("evaltree(%s) called\n",
n == NULL ? "NULL" : "-n"));
if (nflag == 0)
exitstatus = 0;
goto out;
}
#ifndef SMALL
displayhist = 1; /* show history substitutions done with fc */
#endif
CTRACE(DBG_EVAL, ("pid %d, evaltree(%p: %s(%d), %#x) called\n",
getpid(), n, NODETYPENAME(n->type), n->type, flags));
switch (n->type) {
case NSEMI:
evaltree(n->nbinary.ch1, (sflags & EV_TESTED) |
(n->nbinary.ch2 ? EV_MORE : 0));
if (nflag || evalskip)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NAND:
evaltree(n->nbinary.ch1, EV_TESTED | EV_MORE);
if (nflag || evalskip || exitstatus != 0)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NOR:
evaltree(n->nbinary.ch1, EV_TESTED | EV_MORE);
if (nflag || evalskip || exitstatus == 0)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NREDIR:
expredir(n->nredir.redirect);
if (xflag && n->nredir.redirect) {
union node *rn;
outxstr(expandstr(ps4val(), line_number));
outxstr("using redirections:");
for (rn = n->nredir.redirect; rn; rn = rn->nfile.next)
(void) outredir(outx, rn, ' ');
outxstr(" do\n");
flushout(outx);
}
redirect(n->nredir.redirect, REDIR_PUSH | REDIR_KEEP);
evaltree(n->nredir.n, flags);
popredir();
if (xflag && n->nredir.redirect) {
outxstr(expandstr(ps4val(), line_number));
outxstr("done\n");
flushout(outx);
}
break;
case NSUBSHELL:
evalsubshell(n, flags & ~EV_MORE);
do_etest = !(flags & EV_TESTED);
break;
case NBACKGND:
evalsubshell(n, flags & ~EV_MORE);
break;
case NIF: {
evaltree(n->nif.test, EV_TESTED | EV_MORE);
if (nflag || 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, sflags);
break;
case NFOR:
evalfor(n, sflags);
break;
case NCASE:
evalcase(n, sflags);
break;
case NDEFUN:
CTRACE(DBG_EVAL, ("Defining fn %s @%d%s\n", n->narg.text,
n->narg.lineno, fnline1 ? " LINENO=1" : ""));
defun(n->narg.text, n->narg.next, n->narg.lineno);
exitstatus = 0;
break;
case NNOT:
evaltree(n->nnot.com, (sflags & EV_MORE) | EV_TESTED);
exitstatus = !exitstatus;
break;
case NDNOT:
evaltree(n->nnot.com, (sflags & EV_MORE) | EV_TESTED);
if (exitstatus != 0)
exitstatus = 1;
break;
case NPIPE:
evalpipe(n);
do_etest = !(flags & EV_TESTED);
break;
case NCMD:
evalcommand(n, flags, NULL);
do_etest = !(flags & EV_TESTED);
break;
default:
#ifdef NODETYPENAME
out1fmt("Node type = %d(%s)\n", n->type, NODETYPENAME(n->type));
#else
out1fmt("Node type = %d\n", n->type);
#endif
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;
CTRACE(DBG_EVAL, ("evalloop %s:", NODETYPENAME(n->type)));
VXTRACE(DBG_EVAL, (" "), showtree(n->nbinary.ch1));
VXTRACE(DBG_EVAL, ("evalloop do: "), showtree(n->nbinary.ch2));
VTRACE(DBG_EVAL, ("evalloop done\n"));
CTRACE(DBG_EVAL, ("\n"));
for (;;) {
evaltree(n->nbinary.ch1, EV_TESTED | EV_MORE);
if (nflag)
break;
if (evalskip) {
skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = SKIPNONE;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = SKIPNONE;
break;
}
if (n->type == NWHILE) {
if (exitstatus != 0)
break;
} else {
if (exitstatus == 0)
break;
}
evaltree(n->nbinary.ch2, (flags & EV_TESTED) | EV_MORE);
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;
status = nflag ? exitstatus : 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) {
int f = flags & (EV_TESTED | EV_MORE);
if (sp->next)
f |= EV_MORE;
if (xflag) {
outxstr(expandstr(ps4val(), line_number));
outxstr("for ");
outxstr(n->nfor.var);
outxc('=');
outxshstr(sp->text);
outxc('\n');
flushout(outx);
}
setvar(n->nfor.var, sp->text, 0);
evaltree(n->nfor.body, f);
status = exitstatus;
if (nflag)
break;
if (evalskip) {
if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = SKIPNONE;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = SKIPNONE;
break;
}
}
loopnest--;
exitstatus = status;
out:
popstackmark(&smark);
}
STATIC void
evalcase(union node *n, int flags)
{
union node *cp, *ncp;
union node *patp;
struct arglist arglist;
struct stackmark smark;
int status = 0;
setstackmark(&smark);
arglist.lastp = &arglist.list;
line_number = n->ncase.lineno;
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) {
line_number = patp->narg.lineno;
if (casematch(patp, arglist.list->text)) {
while (cp != NULL && evalskip == 0 &&
nflag == 0) {
if (cp->type == NCLISTCONT)
ncp = cp->nclist.next;
else
ncp = NULL;
line_number = cp->nclist.lineno;
evaltree(cp->nclist.body,
ncp ? (flags | EV_MORE) : flags);
status = exitstatus;
cp = ncp;
}
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);
if (xflag && n->nredir.redirect) {
union node *rn;
outxstr(expandstr(ps4val(), line_number));
outxstr("using redirections:");
for (rn = n->nredir.redirect; rn; rn = rn->nfile.next)
(void) outredir(outx, rn, ' ');
outxstr(" do subshell\n");
flushout(outx);
}
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, REDIR_KEEP);
/* never returns */
evaltree(n->nredir.n, flags | EV_EXIT);
}
exitstatus = backgnd ? 0 : waitforjob(jp);
INTON;
if (!backgnd && xflag && n->nredir.redirect) {
outxstr(expandstr(ps4val(), line_number));
outxstr("done subshell\n");
flushout(outx);
}
}
/*
* 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_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];
CTRACE(DBG_EVAL, ("evalpipe(%p) called\n", 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)
movefd(prevfd, 0);
if (pip[1] >= 0) {
close(pip[0]);
movefd(pip[1], 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);
CTRACE(DBG_EVAL, ("evalpipe: job done exit status %d\n",
exitstatus));
} else
exitstatus = 0;
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 (nflag || 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]);
movefd(pip[1], 1);
eflag = 0;
evaltree(n, EV_EXIT);
/* NOTREACHED */
}
close(pip[1]);
result->fd = pip[0];
result->jp = jp;
INTON;
}
out:
popstackmark(&smark);
CTRACE(DBG_EVAL, ("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;
extern char *trap[];
/*
* 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;
const int savefuncline = funclinebase;
const int savefuncabs = funclineabs;
vforked = 0;
/* First expand the arguments. */
CTRACE(DBG_EVAL, ("evalcommand(%p, %d) called [%s]\n", cmd, flags,
cmd->ncmd.args ? cmd->ncmd.args->narg.text : ""));
setstackmark(&smark);
back_exitstatus = 0;
line_number = cmd->ncmd.lineno;
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;
line_number = argp->narg.lineno;
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;
line_number = argp->narg.lineno;
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) {
VTRACE(DBG_EVAL, ("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;
union node *rn;
outxstr(expandstr(ps4val(), line_number));
for (sp = varlist.list ; sp ; sp = sp->next) {
char *p;
if (sep != 0)
outxc(sep);
/*
* The "var=" part should not be quoted, regardless
* of the value, or it would not represent an
* assignment, but rather a command
*/
p = strchr(sp->text, '=');
if (p != NULL) {
*p = '\0'; /*XXX*/
outxshstr(sp->text);
outxc('=');
*p++ = '='; /*XXX*/
} else
p = sp->text;
outxshstr(p);
sep = ' ';
}
for (sp = arglist.list ; sp ; sp = sp->next) {
if (sep != 0)
outxc(sep);
outxshstr(sp->text);
sep = ' ';
}
for (rn = cmd->ncmd.redirect; rn; rn = rn->nfile.next)
if (outredir(outx, rn, sep))
sep = ' ';
outxc('\n');
flushout(outx);
}
/* 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 || (trap[0] && (flags & EV_EXIT) != 0)
|| (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 (mode)
flags &= ~EV_MORE;
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 (usefork == 0 && cmdentry.cmdtype == CMDNORMAL) {
pid_t pid;
int serrno;
savelocalvars = localvars;
localvars = NULL;
vforked = 1;
VFORK_BLOCK
switch (pid = vfork()) {
case -1:
serrno = errno;
VTRACE(DBG_EVAL, ("vfork() failed, errno=%d\n",
serrno));
INTON;
error("Cannot vfork (%s)", strerror(serrno));
break;
case 0:
/* Make sure that exceptions only unwind to
* after the vfork(2)
*/
SHELL_FORKED();
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:
VFORK_UNDO();
/* restore from vfork(2) */
handler = savehandler;
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;
}
/*
* Here the child has left home,
* getting on with its life, so
* so must we...
*/
vforked = 0;
forkparent(jp, cmd, mode, pid);
goto parent;
}
VFORK_END
} 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]);
movefd(pip[1], 1);
}
flags |= EV_EXIT;
}
/* This is the child process if a fork occurred. */
/* Execute the command. */
switch (cmdentry.cmdtype) {
case CMDFUNCTION:
VXTRACE(DBG_EVAL, ("Shell function%s: ",vforked?" VF":""),
trargs(argv));
redirect(cmd->ncmd.redirect, flags & EV_MORE ? REDIR_PUSH : 0);
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;
funclinebase = savefuncline;
funclineabs = savefuncabs;
handler = savehandler;
longjmp(handler->loc, 1);
}
savehandler = handler;
handler = &jmploc;
if (cmdentry.u.func) {
if (cmdentry.lno_frel)
funclinebase = cmdentry.lineno - 1;
else
funclinebase = 0;
funclineabs = cmdentry.lineno;
VTRACE(DBG_EVAL,
("function: node: %d '%s' # %d%s; funclinebase=%d\n",
cmdentry.u.func->type,
NODETYPENAME(cmdentry.u.func->type),
cmdentry.lineno, cmdentry.lno_frel?" (=1)":"",
funclinebase));
}
listmklocal(varlist.list, VEXPORT);
/* 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;
funclinebase = savefuncline;
funclineabs = savefuncabs;
freeparam(&shellparam);
shellparam = saveparam;
handler = savehandler;
if (flags & EV_MORE)
popredir();
INTON;
if (evalskip == SKIPFUNC) {
evalskip = SKIPNONE;
skipcount = 0;
}
if (flags & EV_EXIT)
exitshell(exitstatus);
break;
case CMDBUILTIN:
case CMDSPLBLTIN:
VXTRACE(DBG_EVAL, ("builtin command%s: ",vforked?" VF":""), trargs(argv));
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;
temp_path = 0;
if (!setjmp(jmploc.loc)) {
/*
* We need to ensure the command hash table isn't
* corrupted 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;
temp_path = 1;
mklocal(path - 5 /* 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;
builtin_flags = flags;
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:
VXTRACE(DBG_EVAL, ("normal command%s: ", vforked?" VF":""),
trargs(argv));
redirect(cmd->ncmd.redirect,
(vforked ? REDIR_VFORK : 0) | REDIR_KEEP);
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) */
exitstatus = 0; /* if not altered just below */
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)
/* implement $_ for whatever use that really is */
(void) setvarsafe("_", lastarg, VNOERROR);
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());
}
int
in_function(void)
{
return funcnest;
}
enum skipstate
current_skipstate(void)
{
return evalskip;
}
void
stop_skipping(void)
{
evalskip = SKIPNONE;
skipcount = 0;
}
/*
* 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 <= 0)
error("invalid count: %d", n);
if (n > loopnest)
n = loopnest;
if (n > 0) {
evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
skipcount = n;
}
return 0;
}
int
dotcmd(int argc, char **argv)
{
exitstatus = 0;
if (argc >= 2) { /* That's what SVR2 does */
char *fullname;
/*
* dot_funcnest needs to be 0 when not in a dotcmd, so it
* cannot be restored with (funcnest + 1).
*/
int dot_funcnest_old;
struct stackmark smark;
setstackmark(&smark);
fullname = find_dot_file(argv[1]);
setinputfile(fullname, 1);
commandname = fullname;
dot_funcnest_old = dot_funcnest;
dot_funcnest = funcnest + 1;
cmdloop(0);
dot_funcnest = dot_funcnest_old;
popfile();
popstackmark(&smark);
}
return exitstatus;
}
/*
* Take commands from a file. To be compatible we should do a path
* search for the file, which is necessary to find sub-commands.
*/
STATIC char *
find_dot_file(char *basename)
{
char *fullname;
const char *path = pathval();
struct stat statb;
/* don't try this for absolute or relative paths */
if (strchr(basename, '/')) {
if (stat(basename, &statb) == 0) {
if (S_ISDIR(statb.st_mode))
error("%s: is a directory", basename);
if (S_ISBLK(statb.st_mode))
error("%s: is a block device", basename);
return basename;
}
} else while ((fullname = padvance(&path, basename, 1)) != NULL) {
if ((stat(fullname, &statb) == 0)) {
/* weird format is to ease future code... */
if (S_ISDIR(statb.st_mode) || S_ISBLK(statb.st_mode))
;
#if notyet
else if (unreadable()) {
/*
* testing this via st_mode is ugly to get
* correct (and would ignore ACLs).
* better way is just to open the file.
* But doing that here would (currently)
* mean opening the file twice, which
* might not be safe. So, defer this
* test until code is restructures so
* we can return a fd. Then we also
* get to fix the mem leak just below...
*/
}
#endif
else {
/*
* Don't bother freeing here, since
* it will be freed by the caller.
* XXX no it won't - a bug for later.
*/
return fullname;
}
}
stunalloc(fullname);
}
/* not found in the PATH */
error("%s: not found", basename);
/* NOTREACHED */
}
/*
* The return command.
*
* Quoth the POSIX standard:
* The return utility shall cause the shell to stop executing the current
* function or dot script. If the shell is not currently executing
* a function or dot script, the results are unspecified.
*
* As for the unspecified part, there seems to be no de-facto standard: bash
* ignores the return with a warning, zsh ignores the return in interactive
* mode but seems to liken it to exit in a script. (checked May 2014)
*
* We choose to silently ignore the return. Older versions of this shell
* set evalskip to SKIPFILE causing the shell to (indirectly) exit. This
* had at least the problem of circumventing the check for stopped jobs,
* which would occur for exit or ^D.
*/
int
returncmd(int argc, char **argv)
{
int ret = argc > 1 ? number(argv[1]) : exitstatus;
if ((dot_funcnest == 0 && funcnest)
|| (dot_funcnest > 0 && funcnest - (dot_funcnest - 1) > 0)) {
evalskip = SKIPFUNC;
skipcount = 1;
} else if (dot_funcnest > 0) {
evalskip = SKIPFILE;
skipcount = 1;
} else {
/* XXX: should a warning be issued? */
ret = 0;
}
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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