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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95";
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
45 #include <sys/resource.h>
46 #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 */
89 struct strlist *cmdenviron;
90 int exitstatus; /* exit status of last command */
91 int oexitstatus; /* saved exit status */
94 STATIC void evalloop(union node *, int);
95 STATIC void evalfor(union node *, int);
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)
190 TRACE(("evaltree(NULL) called\n"));
195 displayhist = 1; /* show history substitutions done with fc */
197 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
200 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
203 evaltree(n->nbinary.ch2, flags);
206 evaltree(n->nbinary.ch1, EV_TESTED);
207 if (evalskip || exitstatus != 0) {
210 evaltree(n->nbinary.ch2, flags);
213 evaltree(n->nbinary.ch1, EV_TESTED);
214 if (evalskip || exitstatus == 0)
216 evaltree(n->nbinary.ch2, flags);
219 expredir(n->nredir.redirect);
220 redirect(n->nredir.redirect, REDIR_PUSH);
221 evaltree(n->nredir.n, flags);
225 evalsubshell(n, flags);
226 do_etest = !(flags & EV_TESTED);
229 evalsubshell(n, flags);
232 evaltree(n->nif.test, EV_TESTED);
236 evaltree(n->nif.ifpart, flags);
237 else if (n->nif.elsepart)
238 evaltree(n->nif.elsepart, flags);
245 evalloop(n, flags & ~EV_EXIT);
248 evalfor(n, flags & ~EV_EXIT);
254 defun(n->narg.text, n->narg.next);
258 evaltree(n->nnot.com, EV_TESTED);
259 exitstatus = !exitstatus;
264 do_etest = !(flags & EV_TESTED);
267 evalcommand(n, flags, (struct backcmd *)NULL);
268 do_etest = !(flags & EV_TESTED);
271 out1fmt("Node type = %d\n", n->type);
278 if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest))
279 exitshell(exitstatus);
284 evalloop(union node *n, int flags)
291 evaltree(n->nbinary.ch1, EV_TESTED);
293 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
297 if (evalskip == SKIPBREAK && --skipcount <= 0)
301 if (n->type == NWHILE) {
308 evaltree(n->nbinary.ch2, flags);
320 evalfor(union node *n, int flags)
322 struct arglist arglist;
325 struct stackmark smark;
327 setstackmark(&smark);
328 arglist.lastp = &arglist.list;
329 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
330 oexitstatus = exitstatus;
331 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
335 *arglist.lastp = NULL;
339 for (sp = arglist.list ; sp ; sp = sp->next) {
340 setvar(n->nfor.var, sp->text, 0);
341 evaltree(n->nfor.body, flags);
343 if (evalskip == SKIPCONT && --skipcount <= 0) {
347 if (evalskip == SKIPBREAK && --skipcount <= 0)
354 popstackmark(&smark);
360 evalcase(union node *n, int flags)
364 struct arglist arglist;
365 struct stackmark smark;
367 setstackmark(&smark);
368 arglist.lastp = &arglist.list;
369 oexitstatus = exitstatus;
371 expandarg(n->ncase.expr, &arglist, EXP_TILDE);
372 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
373 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
374 if (casematch(patp, arglist.list->text)) {
376 evaltree(cp->nclist.body, flags);
383 popstackmark(&smark);
389 * Kick off a subshell to evaluate a tree.
393 evalsubshell(union node *n, int flags)
396 int backgnd = (n->type == NBACKGND);
398 expredir(n->nredir.redirect);
400 if (forkshell(jp, n, backgnd) == 0) {
403 redirect(n->nredir.redirect, 0);
404 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
408 exitstatus = waitforjob(jp, (int *)NULL);
416 * Compute the names of the files in a redirection list.
420 expredir(union node *n)
424 for (redir = n ; redir ; redir = redir->nfile.next) {
427 oexitstatus = exitstatus;
428 switch (redir->type) {
434 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
435 redir->nfile.expfname = fn.list->text;
439 if (redir->ndup.vname) {
440 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
441 fixredir(redir, fn.list->text, 1);
451 * Evaluate a pipeline. All the processes in the pipeline are children
452 * of the process creating the pipeline. (This differs from some versions
453 * of the shell, which make the last process in a pipeline the parent
458 evalpipe(union node *n)
466 TRACE(("evalpipe(%p) called\n", (void *)n));
468 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
471 jp = makejob(n, pipelen);
473 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
479 error("Pipe call failed: %s", strerror(errno));
482 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
489 if (!(prevfd >= 0 && pip[0] == 0))
496 evaltree(lp->n, EV_EXIT);
504 if (n->npipe.backgnd == 0) {
506 exitstatus = waitforjob(jp, (int *)NULL);
507 TRACE(("evalpipe: job done exit status %d\n", exitstatus));
515 * Execute a command inside back quotes. If it's a builtin command, we
516 * want to save its output in a block obtained from malloc. Otherwise
517 * we fork off a subprocess and get the output of the command via a pipe.
518 * Should be called with interrupts off.
522 evalbackcmd(union node *n, struct backcmd *result)
526 struct stackmark smark; /* unnecessary */
528 setstackmark(&smark);
537 if (n->type == NCMD) {
538 exitstatus = oexitstatus;
539 evalcommand(n, EV_BACKCMD, result);
543 error("Pipe call failed: %s", strerror(errno));
545 if (forkshell(jp, n, FORK_NOJOB) == 0) {
552 evaltree(n, EV_EXIT);
559 popstackmark(&smark);
560 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
561 result->fd, result->buf, result->nleft, result->jp));
567 * Execute a simple command.
571 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
573 struct stackmark smark;
575 struct arglist arglist;
576 struct arglist varlist;
584 struct cmdentry cmdentry;
586 struct jmploc jmploc;
587 struct jmploc *volatile savehandler;
588 char *volatile savecmdname;
589 volatile struct shparam saveparam;
590 struct localvar *volatile savelocalvars;
594 int do_clearcmdentry;
596 /* Avoid longjmp clobbering */
601 (void) &do_clearcmdentry;
604 /* First expand the arguments. */
605 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
606 setstackmark(&smark);
607 arglist.lastp = &arglist.list;
608 varlist.lastp = &varlist.list;
610 do_clearcmdentry = 0;
611 oexitstatus = exitstatus;
613 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
614 char *p = argp->narg.text;
615 if (varflag && is_name(*p)) {
618 } while (is_in_name(*p));
620 expandarg(argp, &varlist, EXP_VARTILDE);
624 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
627 *arglist.lastp = NULL;
628 *varlist.lastp = NULL;
629 expredir(cmd->ncmd.redirect);
631 for (sp = arglist.list ; sp ; sp = sp->next)
633 argv = stalloc(sizeof (char *) * (argc + 1));
635 for (sp = arglist.list ; sp ; sp = sp->next) {
636 TRACE(("evalcommand arg: %s\n", sp->text));
641 if (iflag && funcnest == 0 && argc > 0)
645 /* Print the command if xflag is set. */
649 for (sp = varlist.list ; sp ; sp = sp->next) {
655 for (sp = arglist.list ; sp ; sp = sp->next) {
665 /* Now locate the command. */
667 /* Variable assignment(s) without command */
668 cmdentry.cmdtype = CMDBUILTIN;
669 cmdentry.u.index = BLTINCMD;
670 cmdentry.special = 1;
672 static const char PATH[] = "PATH=";
673 char *path = pathval();
676 * Modify the command lookup path, if a PATH= assignment
679 for (sp = varlist.list ; sp ; sp = sp->next)
680 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
681 path = sp->text + sizeof(PATH) - 1;
683 * On `PATH=... command`, we need to make
684 * sure that the command isn't using the
685 * non-updated hash table of the outer PATH
686 * setting and we need to make sure that
687 * the hash table isn't filled with items
688 * from the temporary setting.
690 * It would be better to forbit using and
691 * updating the table while this command
692 * runs, by the command finding mechanism
693 * is heavily integrated with hash handling,
694 * so we just delete the hash before and after
695 * the command runs. Partly deleting like
696 * changepatch() does doesn't seem worth the
697 * bookinging effort, since most such runs add
698 * directories in front of the new PATH.
701 do_clearcmdentry = 1;
704 find_command(argv[0], &cmdentry, 1, path);
705 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */
710 /* implement the bltin builtin here */
711 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
716 if ((cmdentry.u.index = find_builtin(*argv,
717 &cmdentry.special)) < 0) {
718 outfmt(&errout, "%s: not found\n", *argv);
723 if (cmdentry.u.index != BLTINCMD)
729 /* Fork off a child process if necessary. */
730 if (cmd->ncmd.backgnd
731 || (cmdentry.cmdtype == CMDNORMAL
732 && ((flags & EV_EXIT) == 0 || Tflag))
733 || ((flags & EV_BACKCMD) != 0
734 && (cmdentry.cmdtype != CMDBUILTIN
735 || cmdentry.u.index == CDCMD
736 || cmdentry.u.index == DOTCMD
737 || cmdentry.u.index == EVALCMD))
738 || (cmdentry.cmdtype == CMDBUILTIN &&
739 cmdentry.u.index == COMMANDCMD)) {
740 jp = makejob(cmd, 1);
741 mode = cmd->ncmd.backgnd;
742 if (flags & EV_BACKCMD) {
745 error("Pipe call failed: %s", strerror(errno));
747 if (forkshell(jp, cmd, mode) != 0)
748 goto parent; /* at end of routine */
749 if (flags & EV_BACKCMD) {
760 /* This is the child process if a fork occurred. */
761 /* Execute the command. */
762 if (cmdentry.cmdtype == CMDFUNCTION) {
764 trputs("Shell function: "); trargs(argv);
766 redirect(cmd->ncmd.redirect, REDIR_PUSH);
767 saveparam = shellparam;
768 shellparam.malloc = 0;
769 shellparam.reset = 1;
770 shellparam.nparam = argc - 1;
771 shellparam.p = argv + 1;
772 shellparam.optnext = NULL;
774 savelocalvars = localvars;
777 if (setjmp(jmploc.loc)) {
778 if (exception == EXSHELLPROC)
779 freeparam((struct shparam *)&saveparam);
781 freeparam(&shellparam);
782 shellparam = saveparam;
785 localvars = savelocalvars;
786 handler = savehandler;
787 longjmp(handler->loc, 1);
789 savehandler = handler;
791 for (sp = varlist.list ; sp ; sp = sp->next)
794 if (flags & EV_TESTED)
795 evaltree(cmdentry.u.func, EV_TESTED);
797 evaltree(cmdentry.u.func, 0);
801 localvars = savelocalvars;
802 freeparam(&shellparam);
803 shellparam = saveparam;
804 handler = savehandler;
807 if (evalskip == SKIPFUNC) {
812 exitshell(exitstatus);
813 } else if (cmdentry.cmdtype == CMDBUILTIN) {
815 trputs("builtin command: "); trargs(argv);
817 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
818 if (flags == EV_BACKCMD) {
820 memout.nextc = memout.buf;
824 savecmdname = commandname;
825 cmdenviron = varlist.list;
827 if (setjmp(jmploc.loc)) {
829 exitstatus = (e == EXINT)? SIGINT+128 : 2;
832 savehandler = handler;
834 redirect(cmd->ncmd.redirect, mode);
835 if (cmdentry.special)
836 listsetvar(cmdenviron);
837 commandname = argv[0];
839 optptr = NULL; /* initialize nextopt */
840 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
847 if (e != EXSHELLPROC) {
848 commandname = savecmdname;
849 if (flags & EV_EXIT) {
850 exitshell(exitstatus);
853 handler = savehandler;
855 if ((e != EXERROR && e != EXEXEC)
860 if (cmdentry.u.index != EXECCMD)
862 if (flags == EV_BACKCMD) {
863 backcmd->buf = memout.buf;
864 backcmd->nleft = memout.nextc - memout.buf;
869 trputs("normal command: "); trargs(argv);
872 redirect(cmd->ncmd.redirect, 0);
873 for (sp = varlist.list ; sp ; sp = sp->next)
874 setvareq(sp->text, VEXPORT|VSTACK);
875 envp = environment();
876 shellexec(argv, envp, pathval(), cmdentry.u.index);
881 parent: /* parent process gets here (if we forked) */
882 if (mode == 0) { /* argument to fork */
884 exitstatus = waitforjob(jp, &realstatus);
886 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
887 evalskip = SKIPBREAK;
888 skipcount = loopnest;
890 } else if (mode == 2) {
891 backcmd->fd = pip[0];
898 setvar("_", lastarg, 0);
899 if (do_clearcmdentry)
901 popstackmark(&smark);
907 * Search for a command. This is called before we fork so that the
908 * location of the command will be available in the parent as well as
909 * the child. The check for "goodname" is an overly conservative
910 * check that the name will not be subject to expansion.
914 prehash(union node *n)
916 struct cmdentry entry;
918 if (n && n->type == NCMD && n->ncmd.args)
919 if (goodname(n->ncmd.args->narg.text))
920 find_command(n->ncmd.args->narg.text, &entry, 0,
927 * Builtin commands. Builtin commands whose functions are closely
928 * tied to evaluation are implemented here.
932 * No command given, or a bltin command with no arguments.
936 bltincmd(int argc __unused, char **argv __unused)
939 * Preserve exitstatus of a previous possible redirection
947 * Handle break and continue commands. Break, continue, and return are
948 * all handled by setting the evalskip flag. The evaluation routines
949 * above all check this flag, and if it is set they start skipping
950 * commands rather than executing them. The variable skipcount is
951 * the number of loops to break/continue, or the number of function
952 * levels to return. (The latter is always 1.) It should probably
953 * be an error to break out of more loops than exist, but it isn't
954 * in the standard shell so we don't make it one here.
958 breakcmd(int argc, char **argv)
960 int n = argc > 1 ? number(argv[1]) : 1;
965 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
972 * The `command' command.
975 commandcmd(int argc, char **argv)
977 static char stdpath[] = _PATH_STDPATH;
978 struct jmploc loc, *old;
984 for (sp = cmdenviron; sp ; sp = sp->next)
985 setvareq(sp->text, VEXPORT|VSTACK);
988 optind = optreset = 1;
990 while ((ch = getopt(argc, argv, "pvV")) != -1) {
996 cmd = TYPECMD_SMALLV;
1003 error("unknown option: -%c", optopt);
1011 error("wrong number of arguments");
1012 return typecmd_impl(2, argv - 1, cmd);
1017 if (setjmp(handler->loc) == 0)
1018 shellexec(argv, environment(), path, 0);
1020 if (exception == EXEXEC)
1026 * Do nothing successfully if no command was specified;
1027 * ksh also does this.
1034 * The return command.
1038 returncmd(int argc, char **argv)
1040 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1043 evalskip = SKIPFUNC;
1046 /* skip the rest of the file */
1047 evalskip = SKIPFILE;
1055 falsecmd(int argc __unused, char **argv __unused)
1062 truecmd(int argc __unused, char **argv __unused)
1069 execcmd(int argc, char **argv)
1074 iflag = 0; /* exit on error */
1077 for (sp = cmdenviron; sp ; sp = sp->next)
1078 setvareq(sp->text, VEXPORT|VSTACK);
1079 shellexec(argv + 1, environment(), pathval(), 0);
1087 timescmd(int argc __unused, char **argv __unused)
1090 long shumins, shsmins, chumins, chsmins;
1091 double shusecs, shssecs, chusecs, chssecs;
1093 if (getrusage(RUSAGE_SELF, &ru) < 0)
1095 shumins = ru.ru_utime.tv_sec / 60;
1096 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1097 shsmins = ru.ru_stime.tv_sec / 60;
1098 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1099 if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1101 chumins = ru.ru_utime.tv_sec / 60;
1102 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1103 chsmins = ru.ru_stime.tv_sec / 60;
1104 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1105 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1106 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);