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36 * @(#)eval.c 8.9 (Berkeley) 6/8/95
37 * $FreeBSD: src/bin/sh/eval.c,v 1.53 2006/06/15 07:57:05 stefanf Exp $
38 * $DragonFly: src/bin/sh/eval.c,v 1.12 2007/02/04 19:45:24 corecode Exp $
42 #include <sys/resource.h>
43 #include <sys/wait.h> /* For WIFSIGNALED(status) */
75 #include "myhistedit.h"
79 /* flags in argument to evaltree */
80 #define EV_EXIT 01 /* exit after evaluating tree */
81 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */
82 #define EV_BACKCMD 04 /* command executing within back quotes */
84 int evalskip; /* set if we are skipping commands */
85 STATIC int skipcount; /* number of levels to skip */
86 MKINIT int loopnest; /* current loop nesting level */
87 int funcnest; /* depth of function calls */
90 const char *commandname;
91 struct strlist *cmdenviron;
92 int exitstatus; /* exit status of last command */
93 int oexitstatus; /* saved exit status */
96 STATIC void evalloop(union node *, int);
97 STATIC void evalfor(union node *, int);
98 STATIC void evalcase(union node *, int);
99 STATIC void evalsubshell(union node *, int);
100 STATIC void expredir(union node *);
101 STATIC void evalpipe(union node *);
102 STATIC void evalcommand(union node *, int, struct backcmd *);
103 STATIC void prehash(union node *);
107 * Called to reset things after an exception.
131 evalcmd(int argc, char **argv)
140 STARTSTACKSTR(concat);
144 STPUTC(*p++, concat);
145 if ((p = *ap++) == NULL)
149 STPUTC('\0', concat);
150 p = grabstackstr(concat);
159 * Execute a command or commands contained in a string.
166 struct stackmark smark;
168 setstackmark(&smark);
169 setinputstring(s, 1);
170 while ((n = parsecmd(0)) != NEOF) {
172 popstackmark(&smark);
175 popstackmark(&smark);
181 * Evaluate a parse tree. The value is left in the global variable
186 evaltree(union node *n, int flags)
192 TRACE(("evaltree(NULL) called\n"));
197 displayhist = 1; /* show history substitutions done with fc */
199 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
202 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
205 evaltree(n->nbinary.ch2, flags);
208 evaltree(n->nbinary.ch1, EV_TESTED);
209 if (evalskip || exitstatus != 0) {
212 evaltree(n->nbinary.ch2, flags);
215 evaltree(n->nbinary.ch1, EV_TESTED);
216 if (evalskip || exitstatus == 0)
218 evaltree(n->nbinary.ch2, flags);
221 expredir(n->nredir.redirect);
222 redirect(n->nredir.redirect, REDIR_PUSH);
223 evaltree(n->nredir.n, flags);
227 evalsubshell(n, flags);
228 do_etest = !(flags & EV_TESTED);
231 evalsubshell(n, flags);
234 evaltree(n->nif.test, EV_TESTED);
238 evaltree(n->nif.ifpart, flags);
239 else if (n->nif.elsepart)
240 evaltree(n->nif.elsepart, flags);
247 evalloop(n, flags & ~EV_EXIT);
250 evalfor(n, flags & ~EV_EXIT);
256 defun(n->narg.text, n->narg.next);
260 evaltree(n->nnot.com, EV_TESTED);
261 exitstatus = !exitstatus;
266 do_etest = !(flags & EV_TESTED);
269 evalcommand(n, flags, (struct backcmd *)NULL);
270 do_etest = !(flags & EV_TESTED);
273 out1fmt("Node type = %d\n", n->type);
280 if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest))
281 exitshell(exitstatus);
286 evalloop(union node *n, int flags)
293 evaltree(n->nbinary.ch1, EV_TESTED);
295 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
299 if (evalskip == SKIPBREAK && --skipcount <= 0)
303 if (n->type == NWHILE) {
310 evaltree(n->nbinary.ch2, flags);
322 evalfor(union node *n, int flags)
324 struct arglist arglist;
327 struct stackmark smark;
329 setstackmark(&smark);
330 arglist.lastp = &arglist.list;
331 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
332 oexitstatus = exitstatus;
333 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
337 *arglist.lastp = NULL;
341 for (sp = arglist.list ; sp ; sp = sp->next) {
342 setvar(n->nfor.var, sp->text, 0);
343 evaltree(n->nfor.body, flags);
345 if (evalskip == SKIPCONT && --skipcount <= 0) {
349 if (evalskip == SKIPBREAK && --skipcount <= 0)
356 popstackmark(&smark);
362 evalcase(union node *n, int flags)
366 struct arglist arglist;
367 struct stackmark smark;
369 setstackmark(&smark);
370 arglist.lastp = &arglist.list;
371 oexitstatus = exitstatus;
372 expandarg(n->ncase.expr, &arglist, EXP_TILDE);
373 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
374 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
375 if (casematch(patp, arglist.list->text)) {
377 evaltree(cp->nclist.body, flags);
384 popstackmark(&smark);
390 * Kick off a subshell to evaluate a tree.
394 evalsubshell(union node *n, int flags)
397 int backgnd = (n->type == NBACKGND);
399 expredir(n->nredir.redirect);
401 if (forkshell(jp, n, backgnd) == 0) {
404 redirect(n->nredir.redirect, 0);
405 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
409 exitstatus = waitforjob(jp, (int *)NULL);
417 * Compute the names of the files in a redirection list.
421 expredir(union node *n)
425 for (redir = n ; redir ; redir = redir->nfile.next) {
428 oexitstatus = exitstatus;
429 switch (redir->type) {
435 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
436 redir->nfile.expfname = fn.list->text;
440 if (redir->ndup.vname) {
441 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE);
442 fixredir(redir, fn.list->text, 1);
452 * Evaluate a pipeline. All the processes in the pipeline are children
453 * of the process creating the pipeline. (This differs from some versions
454 * of the shell, which make the last process in a pipeline the parent
459 evalpipe(union node *n)
467 TRACE(("evalpipe(%p) called\n", (void *)n));
469 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
472 jp = makejob(n, pipelen);
474 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
481 error("Pipe call failed: %s", strerror(errno));
484 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
491 if (!(prevfd >= 0 && pip[0] == 0))
498 evaltree(lp->n, EV_EXIT);
506 if (n->npipe.backgnd == 0) {
508 exitstatus = waitforjob(jp, (int *)NULL);
509 TRACE(("evalpipe: job done exit status %d\n", exitstatus));
517 * Execute a command inside back quotes. If it's a builtin command, we
518 * want to save its output in a block obtained from malloc. Otherwise
519 * we fork off a subprocess and get the output of the command via a pipe.
520 * Should be called with interrupts off.
524 evalbackcmd(union node *n, struct backcmd *result)
528 struct stackmark smark; /* unnecessary */
530 setstackmark(&smark);
539 if (n->type == NCMD) {
540 exitstatus = oexitstatus;
541 evalcommand(n, EV_BACKCMD, result);
545 error("Pipe call failed: %s", strerror(errno));
547 if (forkshell(jp, n, FORK_NOJOB) == 0) {
554 evaltree(n, EV_EXIT);
561 popstackmark(&smark);
562 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
563 result->fd, result->buf, result->nleft, result->jp));
569 * Execute a simple command.
573 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
575 struct stackmark smark;
577 struct arglist arglist;
578 struct arglist varlist;
579 volatile int flags = flgs;
580 char **volatile argv;
587 struct cmdentry cmdentry;
589 struct jmploc jmploc;
590 struct jmploc *volatile savehandler = NULL;
591 const char *volatile savecmdname;
592 volatile struct shparam saveparam;
593 struct localvar *volatile savelocalvars;
595 char *volatile lastarg;
597 volatile int do_clearcmdentry;
599 /* First expand the arguments. */
600 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
601 setstackmark(&smark);
602 arglist.lastp = &arglist.list;
603 varlist.lastp = &varlist.list;
605 do_clearcmdentry = 0;
606 oexitstatus = exitstatus;
608 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
609 char *p = argp->narg.text;
610 if (varflag && is_name(*p)) {
613 } while (is_in_name(*p));
615 expandarg(argp, &varlist, EXP_VARTILDE);
619 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
622 *arglist.lastp = NULL;
623 *varlist.lastp = NULL;
624 expredir(cmd->ncmd.redirect);
626 for (sp = arglist.list ; sp ; sp = sp->next)
628 argv = stalloc(sizeof (char *) * (argc + 1));
630 for (sp = arglist.list ; sp ; sp = sp->next) {
631 TRACE(("evalcommand arg: %s\n", sp->text));
636 if (iflag && funcnest == 0 && argc > 0)
640 /* Print the command if xflag is set. */
644 for (sp = varlist.list ; sp ; sp = sp->next) {
650 for (sp = arglist.list ; sp ; sp = sp->next) {
660 /* Now locate the command. */
662 /* Variable assignment(s) without command */
663 cmdentry.cmdtype = CMDBUILTIN;
664 cmdentry.u.index = BLTINCMD;
665 cmdentry.special = 1;
667 static const char PATH[] = "PATH=";
668 const char *path = pathval();
671 * Modify the command lookup path, if a PATH= assignment
674 for (sp = varlist.list ; sp ; sp = sp->next)
675 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
676 path = sp->text + sizeof(PATH) - 1;
678 * On `PATH=... command`, we need to make
679 * sure that the command isn't using the
680 * non-updated hash table of the outer PATH
681 * setting and we need to make sure that
682 * the hash table isn't filled with items
683 * from the temporary setting.
685 * It would be better to forbit using and
686 * updating the table while this command
687 * runs, by the command finding mechanism
688 * is heavily integrated with hash handling,
689 * so we just delete the hash before and after
690 * the command runs. Partly deleting like
691 * changepatch() does doesn't seem worth the
692 * bookinging effort, since most such runs add
693 * directories in front of the new PATH.
696 do_clearcmdentry = 1;
699 find_command(argv[0], &cmdentry, 1, path);
700 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */
705 /* implement the bltin builtin here */
706 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
711 if ((cmdentry.u.index = find_builtin(*argv,
712 &cmdentry.special)) < 0) {
713 outfmt(&errout, "%s: not found\n", *argv);
718 if (cmdentry.u.index != BLTINCMD)
724 /* Fork off a child process if necessary. */
725 if (cmd->ncmd.backgnd
726 || (cmdentry.cmdtype == CMDNORMAL
727 && ((flags & EV_EXIT) == 0 || Tflag))
728 || ((flags & EV_BACKCMD) != 0
729 && (cmdentry.cmdtype != CMDBUILTIN
730 || cmdentry.u.index == CDCMD
731 || cmdentry.u.index == DOTCMD
732 || cmdentry.u.index == EVALCMD))
733 || (cmdentry.cmdtype == CMDBUILTIN &&
734 cmdentry.u.index == COMMANDCMD)) {
735 jp = makejob(cmd, 1);
736 mode = cmd->ncmd.backgnd;
737 if (flags & EV_BACKCMD) {
740 error("Pipe call failed: %s", strerror(errno));
742 if (forkshell(jp, cmd, mode) != 0)
743 goto parent; /* at end of routine */
744 if (flags & EV_BACKCMD) {
755 /* This is the child process if a fork occurred. */
756 /* Execute the command. */
757 if (cmdentry.cmdtype == CMDFUNCTION) {
759 trputs("Shell function: "); trargs(argv);
761 redirect(cmd->ncmd.redirect, REDIR_PUSH);
762 saveparam = shellparam;
763 shellparam.malloc = 0;
764 shellparam.reset = 1;
765 shellparam.nparam = argc - 1;
766 shellparam.p = argv + 1;
767 shellparam.optnext = NULL;
769 savelocalvars = localvars;
772 if (setjmp(jmploc.loc)) {
773 if (exception == EXSHELLPROC)
774 freeparam(&saveparam);
776 freeparam(&shellparam);
777 shellparam = saveparam;
780 localvars = savelocalvars;
781 handler = savehandler;
782 longjmp(handler->loc, 1);
784 savehandler = handler;
786 for (sp = varlist.list ; sp ; sp = sp->next)
789 if (flags & EV_TESTED)
790 evaltree(cmdentry.u.func, EV_TESTED);
792 evaltree(cmdentry.u.func, 0);
796 localvars = savelocalvars;
797 freeparam(&shellparam);
798 shellparam = saveparam;
799 handler = savehandler;
802 if (evalskip == SKIPFUNC) {
807 exitshell(exitstatus);
808 } else if (cmdentry.cmdtype == CMDBUILTIN) {
810 trputs("builtin command: "); trargs(argv);
812 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
813 if (flags == EV_BACKCMD) {
815 memout.nextc = memout.buf;
819 savecmdname = commandname;
820 cmdenviron = varlist.list;
822 if (setjmp(jmploc.loc)) {
824 exitstatus = (e == EXINT)? SIGINT+128 : 2;
827 savehandler = handler;
829 redirect(cmd->ncmd.redirect, mode);
830 if (cmdentry.special)
831 listsetvar(cmdenviron);
832 commandname = argv[0];
834 optptr = NULL; /* initialize nextopt */
835 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
842 if (e != EXSHELLPROC) {
843 commandname = savecmdname;
844 if (flags & EV_EXIT) {
845 exitshell(exitstatus);
848 handler = savehandler;
850 if ((e != EXERROR && e != EXEXEC)
855 if (cmdentry.u.index != EXECCMD)
857 if (flags == EV_BACKCMD) {
858 backcmd->buf = memout.buf;
859 backcmd->nleft = memout.nextc - memout.buf;
864 trputs("normal command: "); trargs(argv);
867 redirect(cmd->ncmd.redirect, 0);
868 for (sp = varlist.list ; sp ; sp = sp->next)
869 setvareq(sp->text, VEXPORT|VSTACK);
870 envp = environment();
871 shellexec(argv, envp, pathval(), cmdentry.u.index);
876 parent: /* parent process gets here (if we forked) */
877 if (mode == 0) { /* argument to fork */
879 exitstatus = waitforjob(jp, &realstatus);
881 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
882 evalskip = SKIPBREAK;
883 skipcount = loopnest;
885 } else if (mode == 2) {
886 backcmd->fd = pip[0];
893 setvar("_", lastarg, 0);
894 if (do_clearcmdentry)
896 popstackmark(&smark);
902 * Search for a command. This is called before we fork so that the
903 * location of the command will be available in the parent as well as
904 * the child. The check for "goodname" is an overly conservative
905 * check that the name will not be subject to expansion.
909 prehash(union node *n)
911 struct cmdentry entry;
913 if (n && n->type == NCMD && n->ncmd.args)
914 if (goodname(n->ncmd.args->narg.text))
915 find_command(n->ncmd.args->narg.text, &entry, 0,
922 * Builtin commands. Builtin commands whose functions are closely
923 * tied to evaluation are implemented here.
927 * No command given, or a bltin command with no arguments.
931 bltincmd(int argc __unused, char **argv __unused)
934 * Preserve exitstatus of a previous possible redirection
942 * Handle break and continue commands. Break, continue, and return are
943 * all handled by setting the evalskip flag. The evaluation routines
944 * above all check this flag, and if it is set they start skipping
945 * commands rather than executing them. The variable skipcount is
946 * the number of loops to break/continue, or the number of function
947 * levels to return. (The latter is always 1.) It should probably
948 * be an error to break out of more loops than exist, but it isn't
949 * in the standard shell so we don't make it one here.
953 breakcmd(int argc, char **argv)
955 int n = argc > 1 ? number(argv[1]) : 1;
960 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
967 * The `command' command.
970 commandcmd(int argc, char **argv)
972 static char stdpath[] = _PATH_STDPATH;
973 struct jmploc loc, *old;
975 const char *volatile path;
979 for (sp = cmdenviron; sp ; sp = sp->next)
980 setvareq(sp->text, VEXPORT|VSTACK);
983 optind = optreset = 1;
985 while ((ch = getopt(argc, argv, "pvV")) != -1) {
991 cmd = TYPECMD_SMALLV;
998 error("unknown option: -%c", optopt);
1006 error("wrong number of arguments");
1007 return typecmd_impl(2, argv - 1, cmd);
1012 if (setjmp(handler->loc) == 0)
1013 shellexec(argv, environment(), path, 0);
1015 if (exception == EXEXEC)
1021 * Do nothing successfully if no command was specified;
1022 * ksh also does this.
1029 * The return command.
1033 returncmd(int argc, char **argv)
1035 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1038 evalskip = SKIPFUNC;
1041 /* skip the rest of the file */
1042 evalskip = SKIPFILE;
1050 falsecmd(int argc __unused, char **argv __unused)
1057 truecmd(int argc __unused, char **argv __unused)
1064 execcmd(int argc, char **argv)
1069 iflag = 0; /* exit on error */
1072 for (sp = cmdenviron; sp ; sp = sp->next)
1073 setvareq(sp->text, VEXPORT|VSTACK);
1074 shellexec(argv + 1, environment(), pathval(), 0);
1082 timescmd(int argc __unused, char **argv __unused)
1085 long shumins, shsmins, chumins, chsmins;
1086 double shusecs, shssecs, chusecs, chssecs;
1088 if (getrusage(RUSAGE_SELF, &ru) < 0)
1090 shumins = ru.ru_utime.tv_sec / 60;
1091 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1092 shsmins = ru.ru_stime.tv_sec / 60;
1093 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1094 if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1096 chumins = ru.ru_utime.tv_sec / 60;
1097 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1098 chsmins = ru.ru_stime.tv_sec / 60;
1099 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1100 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1101 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);