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fixed bug
[unix-history] / usr / src / bin / sh / eval.c
/*-
* 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.
*
* %sccs.include.redist.c%
*/
#ifndef lint
static char sccsid[] = "@(#)eval.c 8.7 (Berkeley) %G%";
#endif /* not lint */
#include <signal.h>
#include <unistd.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
/* 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 */
/* reasons for skipping commands (see comment on breakcmd routine) */
#define SKIPBREAK 1
#define SKIPCONT 2
#define SKIPFUNC 3
MKINIT 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 */
char *commandname;
struct strlist *cmdenviron;
int exitstatus; /* exit status of last command */
int oexitstatus; /* saved exit status */
STATIC void evalloop __P((union node *));
STATIC void evalfor __P((union node *));
STATIC void evalcase __P((union node *, int));
STATIC void evalsubshell __P((union node *, int));
STATIC void expredir __P((union node *));
STATIC void evalpipe __P((union node *));
STATIC void evalcommand __P((union node *, int, struct backcmd *));
STATIC void prehash __P((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
/*
* The eval commmand.
*/
int
evalcmd(argc, argv)
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);
}
return exitstatus;
}
/*
* Execute a command or commands contained in a string.
*/
void
evalstring(s)
char *s;
{
union node *n;
struct stackmark smark;
setstackmark(&smark);
setinputstring(s, 1);
while ((n = parsecmd(0)) != NEOF) {
evaltree(n, 0);
popstackmark(&smark);
}
popfile();
popstackmark(&smark);
}
/*
* Evaluate a parse tree. The value is left in the global variable
* exitstatus.
*/
void
evaltree(n, flags)
union node *n;
int flags;
{
if (n == NULL) {
TRACE(("evaltree(NULL) called\n"));
exitstatus = 0;
goto out;
}
#ifndef NO_HISTORY
displayhist = 1; /* show history substitutions done with fc */
#endif
TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type));
switch (n->type) {
case NSEMI:
evaltree(n->nbinary.ch1, 0);
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);
break;
case NBACKGND:
evalsubshell(n, flags);
break;
case NIF: {
int status;
evaltree(n->nif.test, EV_TESTED);
status = exitstatus;
exitstatus = 0;
if (evalskip)
goto out;
if (status == 0)
evaltree(n->nif.ifpart, flags);
else if (n->nif.elsepart)
evaltree(n->nif.elsepart, flags);
break;
}
case NWHILE:
case NUNTIL:
evalloop(n);
break;
case NFOR:
evalfor(n);
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);
break;
case NCMD:
evalcommand(n, flags, (struct backcmd *)NULL);
break;
default:
out1fmt("Node type = %d\n", n->type);
flushout(&output);
break;
}
out:
if (pendingsigs)
dotrap();
if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED)))
exitshell(exitstatus);
}
STATIC void
evalloop(n)
union node *n;
{
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, 0);
status = exitstatus;
if (evalskip)
goto skipping;
}
loopnest--;
exitstatus = status;
}
STATIC void
evalfor(n)
union node *n;
{
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, 0);
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(n, flags)
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;
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(n, flags)
union node *n;
int flags;
{
struct job *jp;
int backgnd = (n->type == NBACKGND);
expredir(n->nredir.redirect);
jp = makejob(n, 1);
if (forkshell(jp, n, backgnd) == 0) {
if (backgnd)
flags &=~ EV_TESTED;
redirect(n->nredir.redirect, 0);
evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
}
if (! backgnd) {
INTOFF;
exitstatus = waitforjob(jp);
INTON;
}
}
/*
* Compute the names of the files in a redirection list.
*/
STATIC void
expredir(n)
union node *n;
{
register union node *redir;
for (redir = n ; redir ; redir = redir->nfile.next) {
struct arglist fn;
fn.lastp = &fn.list;
oexitstatus = exitstatus;
switch (redir->type) {
case NFROM:
case NTO:
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(n)
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 (pipe(pip) < 0) {
close(prevfd);
error("Pipe call failed");
}
}
if (forkshell(jp, lp->n, n->npipe.backgnd) == 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]);
}
INTON;
if (n->npipe.backgnd == 0) {
INTOFF;
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(n, result)
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) {
exitstatus = 0;
goto out;
}
if (n->type == NCMD) {
exitstatus = oexitstatus;
evalcommand(n, EV_BACKCMD, result);
} else {
exitstatus = 0;
if (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]);
}
evaltree(n, EV_EXIT);
}
close(pip[1]);
result->fd = pip[0];
result->jp = jp;
}
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));
}
/*
* Execute a simple command.
*/
STATIC void
evalcommand(cmd, flags, backcmd)
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 *volatile savehandler;
char *volatile savecmdname;
volatile struct shparam saveparam;
struct localvar *volatile savelocalvars;
volatile int e;
char *lastarg;
#if __GNUC__
/* Avoid longjmp clobbering */
(void) &argv;
(void) &argc;
(void) &lastarg;
(void) &flags;
#endif
/* First expand the arguments. */
TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
setstackmark(&smark);
arglist.lastp = &arglist.list;
varlist.lastp = &varlist.list;
varflag = 1;
oexitstatus = exitstatus;
exitstatus = 0;
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 == '=') {
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++;
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) {
outc('+', &errout);
for (sp = varlist.list ; sp ; sp = sp->next) {
outc(' ', &errout);
out2str(sp->text);
}
for (sp = arglist.list ; sp ; sp = sp->next) {
outc(' ', &errout);
out2str(sp->text);
}
outc('\n', &errout);
flushout(&errout);
}
/* Now locate the command. */
if (argc == 0) {
cmdentry.cmdtype = CMDBUILTIN;
cmdentry.u.index = BLTINCMD;
} else {
find_command(argv[0], &cmdentry, 1);
if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */
exitstatus = 2;
flushout(&errout);
return;
}
/* implement the bltin builtin here */
if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
for (;;) {
argv++;
if (--argc == 0)
break;
if ((cmdentry.u.index = find_builtin(*argv)) < 0) {
outfmt(&errout, "%s: not found\n", *argv);
exitstatus = 2;
flushout(&errout);
return;
}
if (cmdentry.u.index != BLTINCMD)
break;
}
}
}
/* 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.u.index == DOTCMD
|| cmdentry.u.index == EVALCMD))) {
jp = makejob(cmd, 1);
mode = cmd->ncmd.backgnd;
if (flags & EV_BACKCMD) {
mode = FORK_NOJOB;
if (pipe(pip) < 0)
error("Pipe call failed");
}
if (forkshell(jp, cmd, mode) != 0)
goto parent; /* at end of routine */
if (flags & EV_BACKCMD) {
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. */
if (cmdentry.cmdtype == CMDFUNCTION) {
trputs("Shell function: "); trargs(argv);
redirect(cmd->ncmd.redirect, REDIR_PUSH);
saveparam = shellparam;
shellparam.malloc = 0;
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((struct shparam *)&saveparam);
else {
freeparam(&shellparam);
shellparam = saveparam;
}
poplocalvars();
localvars = savelocalvars;
handler = savehandler;
longjmp(handler->loc, 1);
}
savehandler = handler;
handler = &jmploc;
for (sp = varlist.list ; sp ; sp = sp->next)
mklocal(sp->text);
funcnest++;
evaltree(cmdentry.u.func, 0);
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);
} else if (cmdentry.cmdtype == CMDBUILTIN) {
trputs("builtin command: "); trargs(argv);
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;
}
redirect(cmd->ncmd.redirect, mode);
savecmdname = commandname;
cmdenviron = varlist.list;
e = -1;
if (setjmp(jmploc.loc)) {
e = exception;
exitstatus = (e == EXINT)? SIGINT+128 : 2;
goto cmddone;
}
savehandler = handler;
handler = &jmploc;
commandname = argv[0];
argptr = argv + 1;
optptr = NULL; /* initialize nextopt */
exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
flushall();
cmddone:
out1 = &output;
out2 = &errout;
freestdout();
if (e != EXSHELLPROC) {
commandname = savecmdname;
if (flags & EV_EXIT) {
exitshell(exitstatus);
}
}
handler = savehandler;
if (e != -1) {
if (e != EXERROR || cmdentry.u.index == BLTINCMD
|| cmdentry.u.index == DOTCMD
|| cmdentry.u.index == EVALCMD
#ifndef NO_HISTORY
|| cmdentry.u.index == HISTCMD
#endif
|| cmdentry.u.index == EXECCMD)
exraise(e);
FORCEINTON;
}
if (cmdentry.u.index != EXECCMD)
popredir();
if (flags == EV_BACKCMD) {
backcmd->buf = memout.buf;
backcmd->nleft = memout.nextc - memout.buf;
memout.buf = NULL;
}
} else {
trputs("normal command: "); trargs(argv);
clearredir();
redirect(cmd->ncmd.redirect, 0);
for (sp = varlist.list ; sp ; sp = sp->next)
setvareq(sp->text, VEXPORT|VSTACK);
envp = environment();
shellexec(argv, envp, pathval(), cmdentry.u.index);
/*NOTREACHED*/
}
goto out;
parent: /* parent process gets here (if we forked) */
if (mode == 0) { /* argument to fork */
INTOFF;
exitstatus = waitforjob(jp);
INTON;
} else if (mode == 2) {
backcmd->fd = pip[0];
close(pip[1]);
backcmd->jp = jp;
}
out:
if (lastarg)
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(n)
union node *n;
{
struct cmdentry entry;
if (n->type == NCMD && n->ncmd.args)
if (goodname(n->ncmd.args->narg.text))
find_command(n->ncmd.args->narg.text, &entry, 0);
}
/*
* Builtin commands. Builtin commands whose functions are closely
* tied to evaluation are implemented here.
*/
/*
* No command given, or a bltin command with no arguments. Set the
* specified variables.
*/
int
bltincmd(argc, argv)
int argc;
char **argv;
{
listsetvar(cmdenviron);
/*
* 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(argc, argv)
int argc;
char **argv;
{
int n;
n = 1;
if (argc > 1)
n = number(argv[1]);
if (n > loopnest)
n = loopnest;
if (n > 0) {
evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
skipcount = n;
}
return 0;
}
/*
* The return command.
*/
int
returncmd(argc, argv)
int argc;
char **argv;
{
int ret;
ret = exitstatus;
if (argc > 1)
ret = number(argv[1]);
if (funcnest) {
evalskip = SKIPFUNC;
skipcount = 1;
}
return ret;
}
int
falsecmd(argc, argv)
int argc;
char **argv;
{
return 1;
}
int
truecmd(argc, argv)
int argc;
char **argv;
{
return 0;
}
int
execcmd(argc, argv)
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);
}
return 0;
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.