3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * @(#)eval.c 8.9 (Berkeley) 6/8/95
37 * $FreeBSD: src/bin/sh/eval.c,v 1.27.2.5 2002/08/27 01:36:28 tjr Exp $
38 * $DragonFly: src/bin/sh/eval.c,v 1.6 2006/06/05 15:55:13 dillon Exp $
41 #include <sys/wait.h> /* For WIFSIGNALED(status) */
73 #include "myhistedit.h"
77 /* flags in argument to evaltree */
78 #define EV_EXIT 01 /* exit after evaluating tree */
79 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */
80 #define EV_BACKCMD 04 /* command executing within back quotes */
82 MKINIT int evalskip; /* set if we are skipping commands */
83 STATIC int skipcount; /* number of levels to skip */
84 MKINIT int loopnest; /* current loop nesting level */
85 int funcnest; /* depth of function calls */
88 const char *commandname;
89 struct strlist *cmdenviron;
90 int exitstatus; /* exit status of last command */
91 int oexitstatus; /* saved exit status */
94 STATIC void evalloop(union node *);
95 STATIC void evalfor(union node *);
96 STATIC void evalcase(union node *, int);
97 STATIC void evalsubshell(union node *, int);
98 STATIC void expredir(union node *);
99 STATIC void evalpipe(union node *);
100 STATIC void evalcommand(union node *, int, struct backcmd *);
101 STATIC void prehash(union node *);
105 * Called to reset things after an exception.
129 evalcmd(int argc, char **argv)
138 STARTSTACKSTR(concat);
142 STPUTC(*p++, concat);
143 if ((p = *ap++) == NULL)
147 STPUTC('\0', concat);
148 p = grabstackstr(concat);
157 * Execute a command or commands contained in a string.
164 struct stackmark smark;
166 setstackmark(&smark);
167 setinputstring(s, 1);
168 while ((n = parsecmd(0)) != NEOF) {
170 popstackmark(&smark);
173 popstackmark(&smark);
179 * Evaluate a parse tree. The value is left in the global variable
184 evaltree(union node *n, int flags)
187 TRACE(("evaltree(NULL) called\n"));
192 displayhist = 1; /* show history substitutions done with fc */
194 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type));
197 evaltree(n->nbinary.ch1, 0);
200 evaltree(n->nbinary.ch2, flags);
203 evaltree(n->nbinary.ch1, EV_TESTED);
204 if (evalskip || exitstatus != 0) {
207 evaltree(n->nbinary.ch2, flags);
210 evaltree(n->nbinary.ch1, EV_TESTED);
211 if (evalskip || exitstatus == 0)
213 evaltree(n->nbinary.ch2, flags);
216 expredir(n->nredir.redirect);
217 redirect(n->nredir.redirect, REDIR_PUSH);
218 evaltree(n->nredir.n, flags);
222 evalsubshell(n, flags);
225 evalsubshell(n, flags);
228 evaltree(n->nif.test, EV_TESTED);
232 evaltree(n->nif.ifpart, flags);
233 else if (n->nif.elsepart)
234 evaltree(n->nif.elsepart, flags);
250 defun(n->narg.text, n->narg.next);
254 evaltree(n->nnot.com, EV_TESTED);
255 exitstatus = !exitstatus;
262 evalcommand(n, flags, (struct backcmd *)NULL);
265 out1fmt("Node type = %d\n", n->type);
272 if ((flags & EV_EXIT) || (eflag && exitstatus
273 && !(flags & EV_TESTED) && (n->type == NCMD ||
274 n->type == NSUBSHELL)))
275 exitshell(exitstatus);
280 evalloop(union node *n)
287 evaltree(n->nbinary.ch1, EV_TESTED);
289 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
293 if (evalskip == SKIPBREAK && --skipcount <= 0)
297 if (n->type == NWHILE) {
304 evaltree(n->nbinary.ch2, 0);
316 evalfor(union node *n)
318 struct arglist arglist;
321 struct stackmark smark;
323 setstackmark(&smark);
324 arglist.lastp = &arglist.list;
325 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
326 oexitstatus = exitstatus;
327 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
331 *arglist.lastp = NULL;
335 for (sp = arglist.list ; sp ; sp = sp->next) {
336 setvar(n->nfor.var, sp->text, 0);
337 evaltree(n->nfor.body, 0);
339 if (evalskip == SKIPCONT && --skipcount <= 0) {
343 if (evalskip == SKIPBREAK && --skipcount <= 0)
350 popstackmark(&smark);
356 evalcase(union node *n, int flags)
360 struct arglist arglist;
361 struct stackmark smark;
363 setstackmark(&smark);
364 arglist.lastp = &arglist.list;
365 oexitstatus = exitstatus;
366 expandarg(n->ncase.expr, &arglist, EXP_TILDE);
367 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
368 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
369 if (casematch(patp, arglist.list->text)) {
371 evaltree(cp->nclist.body, flags);
378 popstackmark(&smark);
384 * Kick off a subshell to evaluate a tree.
388 evalsubshell(union node *n, int flags)
391 int backgnd = (n->type == NBACKGND);
393 expredir(n->nredir.redirect);
395 if (forkshell(jp, n, backgnd) == 0) {
398 redirect(n->nredir.redirect, 0);
399 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
403 exitstatus = waitforjob(jp, (int *)NULL);
411 * Compute the names of the files in a redirection list.
415 expredir(union node *n)
419 for (redir = n ; redir ; redir = redir->nfile.next) {
422 oexitstatus = exitstatus;
423 switch (redir->type) {
429 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
430 redir->nfile.expfname = fn.list->text;
434 if (redir->ndup.vname) {
435 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE);
436 fixredir(redir, fn.list->text, 1);
446 * Evaluate a pipeline. All the processes in the pipeline are children
447 * of the process creating the pipeline. (This differs from some versions
448 * of the shell, which make the last process in a pipeline the parent
453 evalpipe(union node *n)
461 TRACE(("evalpipe(0x%lx) called\n", (long)n));
463 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
466 jp = makejob(n, pipelen);
468 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
474 error("Pipe call failed: %s", strerror(errno));
477 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
485 if (!(prevfd >= 0 && pip[0] == 0))
493 evaltree(lp->n, EV_EXIT);
501 if (n->npipe.backgnd == 0) {
503 exitstatus = waitforjob(jp, (int *)NULL);
504 TRACE(("evalpipe: job done exit status %d\n", exitstatus));
512 * Execute a command inside back quotes. If it's a builtin command, we
513 * want to save its output in a block obtained from malloc. Otherwise
514 * we fork off a subprocess and get the output of the command via a pipe.
515 * Should be called with interrupts off.
519 evalbackcmd(union node *n, struct backcmd *result)
523 struct stackmark smark; /* unnecessary */
525 setstackmark(&smark);
534 if (n->type == NCMD) {
535 exitstatus = oexitstatus;
536 evalcommand(n, EV_BACKCMD, result);
540 error("Pipe call failed: %s", strerror(errno));
542 if (forkshell(jp, n, FORK_NOJOB) == 0) {
550 evaltree(n, EV_EXIT);
557 popstackmark(&smark);
558 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n",
559 result->fd, result->buf, result->nleft, result->jp));
565 * Execute a simple command.
569 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
571 struct stackmark smark;
573 struct arglist arglist;
574 struct arglist varlist;
582 struct cmdentry cmdentry;
584 struct jmploc jmploc;
585 struct jmploc *volatile savehandler;
586 const char *volatile savecmdname;
587 volatile struct shparam saveparam;
588 struct localvar *volatile savelocalvars;
592 int do_clearcmdentry;
594 /* Avoid longjmp clobbering */
599 (void) &do_clearcmdentry;
602 /* First expand the arguments. */
603 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
604 setstackmark(&smark);
605 arglist.lastp = &arglist.list;
606 varlist.lastp = &varlist.list;
608 do_clearcmdentry = 0;
609 oexitstatus = exitstatus;
611 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
612 char *p = argp->narg.text;
613 if (varflag && is_name(*p)) {
616 } while (is_in_name(*p));
618 expandarg(argp, &varlist, EXP_VARTILDE);
622 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
625 *arglist.lastp = NULL;
626 *varlist.lastp = NULL;
627 expredir(cmd->ncmd.redirect);
629 for (sp = arglist.list ; sp ; sp = sp->next)
631 argv = stalloc(sizeof (char *) * (argc + 1));
633 for (sp = arglist.list ; sp ; sp = sp->next) {
634 TRACE(("evalcommand arg: %s\n", sp->text));
639 if (iflag && funcnest == 0 && argc > 0)
643 /* Print the command if xflag is set. */
646 for (sp = varlist.list ; sp ; sp = sp->next) {
650 for (sp = arglist.list ; sp ; sp = sp->next) {
658 /* Now locate the command. */
660 cmdentry.cmdtype = CMDBUILTIN;
661 cmdentry.u.index = BLTINCMD;
663 static const char PATH[] = "PATH=";
664 const char *path = pathval();
667 * Modify the command lookup path, if a PATH= assignment
670 for (sp = varlist.list ; sp ; sp = sp->next)
671 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
672 path = sp->text + sizeof(PATH) - 1;
674 * On `PATH=... command`, we need to make
675 * sure that the command isn't using the
676 * non-updated hash table of the outer PATH
677 * setting and we need to make sure that
678 * the hash table isn't filled with items
679 * from the temporary setting.
681 * It would be better to forbit using and
682 * updating the table while this command
683 * runs, by the command finding mechanism
684 * is heavily integrated with hash handling,
685 * so we just delete the hash before and after
686 * the command runs. Partly deleting like
687 * changepatch() does doesn't seem worth the
688 * bookinging effort, since most such runs add
689 * diretories in front of the new PATH.
692 do_clearcmdentry = 1;
695 find_command(argv[0], &cmdentry, 1, path);
696 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */
701 /* implement the bltin builtin here */
702 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
707 if ((cmdentry.u.index = find_builtin(*argv)) < 0) {
708 outfmt(&errout, "%s: not found\n", *argv);
713 if (cmdentry.u.index != BLTINCMD)
719 /* Fork off a child process if necessary. */
720 if (cmd->ncmd.backgnd
721 || (cmdentry.cmdtype == CMDNORMAL
722 && ((flags & EV_EXIT) == 0 || Tflag))
723 || ((flags & EV_BACKCMD) != 0
724 && (cmdentry.cmdtype != CMDBUILTIN
725 || cmdentry.u.index == CDCMD
726 || cmdentry.u.index == DOTCMD
727 || cmdentry.u.index == EVALCMD))
728 || (cmdentry.cmdtype == CMDBUILTIN &&
729 cmdentry.u.index == COMMANDCMD)) {
730 jp = makejob(cmd, 1);
731 mode = cmd->ncmd.backgnd;
732 if (flags & EV_BACKCMD) {
735 error("Pipe call failed: %s", strerror(errno));
737 if (forkshell(jp, cmd, mode) != 0)
738 goto parent; /* at end of routine */
739 if (flags & EV_BACKCMD) {
751 /* This is the child process if a fork occurred. */
752 /* Execute the command. */
753 if (cmdentry.cmdtype == CMDFUNCTION) {
755 trputs("Shell function: "); trargs(argv);
757 redirect(cmd->ncmd.redirect, REDIR_PUSH);
758 saveparam = shellparam;
759 shellparam.malloc = 0;
760 shellparam.reset = 1;
761 shellparam.nparam = argc - 1;
762 shellparam.p = argv + 1;
763 shellparam.optnext = NULL;
765 savelocalvars = localvars;
768 if (setjmp(jmploc.loc)) {
769 if (exception == EXSHELLPROC)
770 freeparam((struct shparam *)&saveparam);
772 freeparam(&shellparam);
773 shellparam = saveparam;
776 localvars = savelocalvars;
777 handler = savehandler;
778 longjmp(handler->loc, 1);
780 savehandler = handler;
782 for (sp = varlist.list ; sp ; sp = sp->next)
785 if (flags & EV_TESTED)
786 evaltree(cmdentry.u.func, EV_TESTED);
788 evaltree(cmdentry.u.func, 0);
792 localvars = savelocalvars;
793 freeparam(&shellparam);
794 shellparam = saveparam;
795 handler = savehandler;
798 if (evalskip == SKIPFUNC) {
803 exitshell(exitstatus);
804 } else if (cmdentry.cmdtype == CMDBUILTIN) {
806 trputs("builtin command: "); trargs(argv);
808 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
809 if (flags == EV_BACKCMD) {
811 memout.nextc = memout.buf;
815 redirect(cmd->ncmd.redirect, mode);
816 savecmdname = commandname;
817 cmdenviron = varlist.list;
819 if (setjmp(jmploc.loc)) {
821 exitstatus = (e == EXINT)? SIGINT+128 : 2;
824 savehandler = handler;
826 commandname = argv[0];
828 optptr = NULL; /* initialize nextopt */
829 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
836 if (e != EXSHELLPROC) {
837 commandname = savecmdname;
838 if (flags & EV_EXIT) {
839 exitshell(exitstatus);
842 handler = savehandler;
844 if ((e != EXERROR && e != EXEXEC)
845 || cmdentry.u.index == BLTINCMD
846 || cmdentry.u.index == DOTCMD
847 || cmdentry.u.index == EVALCMD
849 || cmdentry.u.index == HISTCMD
851 || cmdentry.u.index == EXECCMD
852 || cmdentry.u.index == COMMANDCMD)
856 if (cmdentry.u.index != EXECCMD)
858 if (flags == EV_BACKCMD) {
859 backcmd->buf = memout.buf;
860 backcmd->nleft = memout.nextc - memout.buf;
865 trputs("normal command: "); trargs(argv);
868 redirect(cmd->ncmd.redirect, 0);
869 for (sp = varlist.list ; sp ; sp = sp->next)
870 setvareq(sp->text, VEXPORT|VSTACK);
871 envp = environment();
872 shellexec(argv, envp, pathval(), cmdentry.u.index);
877 parent: /* parent process gets here (if we forked) */
878 if (mode == 0) { /* argument to fork */
880 exitstatus = waitforjob(jp, &realstatus);
882 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
883 evalskip = SKIPBREAK;
884 skipcount = loopnest;
886 } else if (mode == 2) {
887 backcmd->fd = pip[0];
894 setvar("_", lastarg, 0);
895 if (do_clearcmdentry)
897 popstackmark(&smark);
903 * Search for a command. This is called before we fork so that the
904 * location of the command will be available in the parent as well as
905 * the child. The check for "goodname" is an overly conservative
906 * check that the name will not be subject to expansion.
910 prehash(union node *n)
912 struct cmdentry entry;
914 if (n->type == NCMD && n->ncmd.args)
915 if (goodname(n->ncmd.args->narg.text))
916 find_command(n->ncmd.args->narg.text, &entry, 0,
923 * Builtin commands. Builtin commands whose functions are closely
924 * tied to evaluation are implemented here.
928 * No command given, or a bltin command with no arguments. Set the
929 * specified variables.
933 bltincmd(int argc __unused, char **argv __unused)
935 listsetvar(cmdenviron);
937 * Preserve exitstatus of a previous possible redirection
945 * Handle break and continue commands. Break, continue, and return are
946 * all handled by setting the evalskip flag. The evaluation routines
947 * above all check this flag, and if it is set they start skipping
948 * commands rather than executing them. The variable skipcount is
949 * the number of loops to break/continue, or the number of function
950 * levels to return. (The latter is always 1.) It should probably
951 * be an error to break out of more loops than exist, but it isn't
952 * in the standard shell so we don't make it one here.
956 breakcmd(int argc, char **argv)
958 int n = argc > 1 ? number(argv[1]) : 1;
963 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
970 * The `command' command.
973 commandcmd(int argc, char **argv)
975 static char stdpath[] = _PATH_STDPATH;
976 struct jmploc loc, *old;
982 /* Avoid longjmp clobbering */
988 for (sp = cmdenviron; sp ; sp = sp->next)
989 setvareq(sp->text, VEXPORT|VSTACK);
992 optind = optreset = 1;
994 while ((ch = getopt(argc, argv, "p")) != -1) {
1001 error("unknown option: -%c", optopt);
1010 if (setjmp(handler->loc) == 0)
1011 shellexec(argv, environment(), path, 0);
1013 if (exception == EXEXEC)
1019 * Do nothing successfully if no command was specified;
1020 * ksh also does this.
1027 * The return command.
1031 returncmd(int argc, char **argv)
1033 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1036 evalskip = SKIPFUNC;
1039 /* skip the rest of the file */
1040 evalskip = SKIPFILE;
1048 falsecmd(int argc __unused, char **argv __unused)
1055 truecmd(int argc __unused, char **argv __unused)
1062 execcmd(int argc, char **argv)
1067 iflag = 0; /* exit on error */
1070 for (sp = cmdenviron; sp ; sp = sp->next)
1071 setvareq(sp->text, VEXPORT|VSTACK);
1072 shellexec(argv + 1, environment(), pathval(), 0);