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Diffstat (limited to 'src/eval.c')
| -rw-r--r-- | src/eval.c | 1112 |
1 files changed, 1112 insertions, 0 deletions
diff --git a/src/eval.c b/src/eval.c new file mode 100644 index 0000000..d1bf317 --- /dev/null +++ b/src/eval.c @@ -0,0 +1,1112 @@ +/* $NetBSD: eval.c,v 1.71 2003/01/23 03:33:16 rafal 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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 1.71 2003/01/23 03:33:16 rafal Exp $"); +#endif +#endif /* not lint */ + +#include <stdlib.h> +#include <signal.h> +#include <unistd.h> +#include <sys/types.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 SMALL +#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 */ + +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 back_exitstatus; /* exit status of backquoted command */ + + +#if !defined(__alpha__) || (defined(__GNUC__) && __GNUC__ >= 3) +STATIC +#endif +void evaltreenr(union node *, int) __attribute__ ((__noreturn__)); +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 *, int); +#ifdef notyet +STATIC void evalcommand(union node *, int, struct backcmd *); +#else +STATIC void evalcommand(union node *, int); +#endif +STATIC int evalbltin(const struct builtincmd *, int, char **); +STATIC int evalfun(struct funcnode *, int, char **, int); +STATIC void prehash(union node *); +STATIC int eprintlist(struct output *, struct strlist *, int); +STATIC int bltincmd(int, char **); + + +STATIC const struct builtincmd bltin = { + name: nullstr, + builtin: bltincmd +}; + + +/* + * Called to reset things after an exception. + */ + +#ifdef mkinit +INCLUDE "eval.h" + +RESET { + evalskip = 0; + loopnest = 0; + funcnest = 0; +} +#endif + + + +/* + * 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 (;;) { + concat = stputs(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(char *s) +{ + union node *n; + struct stackmark smark; + + setstackmark(&smark); + setinputstring(s); + + while ((n = parsecmd(0)) != NEOF) { + evaltree(n, 0); + popstackmark(&smark); + if (evalskip) + break; + } + popfile(); + popstackmark(&smark); +} + + + +/* + * Evaluate a parse tree. The value is left in the global variable + * exitstatus. + */ + +void +evaltree(union node *n, int flags) +{ + int checkexit = 0; + void (*evalfn)(union node *, int); + unsigned isor; + int status; + if (n == NULL) { + TRACE(("evaltree(NULL) called\n")); + goto out; + } +#ifndef SMALL + displayhist = 1; /* show history substitutions done with fc */ +#endif + TRACE(("pid %d, evaltree(%p: %d, %d) called\n", + getpid(), n, n->type, flags)); + switch (n->type) { + default: +#ifdef DEBUG + out1fmt("Node type = %d\n", n->type); +#ifndef USE_GLIBC_STDIO + flushout(out1); +#endif + break; +#endif + case NNOT: + evaltree(n->nnot.com, EV_TESTED); + status = !exitstatus; + goto setstatus; + case NREDIR: + expredir(n->nredir.redirect); + status = redirectsafe(n->nredir.redirect, REDIR_PUSH); + if (!status) { + evaltree(n->nredir.n, flags & EV_TESTED); + status = exitstatus; + } + popredir(0); + goto setstatus; + case NCMD: +#ifdef notyet + if (eflag && !(flags & EV_TESTED)) + checkexit = ~0; + evalcommand(n, flags, (struct backcmd *)NULL); + break; +#else + evalfn = evalcommand; +checkexit: + if (eflag && !(flags & EV_TESTED)) + checkexit = ~0; + goto calleval; +#endif + case NFOR: + evalfn = evalfor; + goto calleval; + case NWHILE: + case NUNTIL: + evalfn = evalloop; + goto calleval; + case NSUBSHELL: + case NBACKGND: + evalfn = evalsubshell; + goto calleval; + case NPIPE: + evalfn = evalpipe; +#ifdef notyet + if (eflag && !(flags & EV_TESTED)) + checkexit = ~0; + goto calleval; +#else + goto checkexit; +#endif + case NCASE: + evalfn = evalcase; + goto calleval; + case NAND: + case NOR: + case NSEMI: +#if NAND + 1 != NOR +#error NAND + 1 != NOR +#endif +#if NOR + 1 != NSEMI +#error NOR + 1 != NSEMI +#endif + isor = n->type - NAND; + evaltree( + n->nbinary.ch1, + (flags | ((isor >> 1) - 1)) & EV_TESTED + ); + if (!exitstatus == isor) + break; + if (!evalskip) { + n = n->nbinary.ch2; +evaln: + evalfn = evaltree; +calleval: + evalfn(n, flags); + break; + } + break; + case NIF: + evaltree(n->nif.test, EV_TESTED); + if (evalskip) + break; + if (exitstatus == 0) { + n = n->nif.ifpart; + goto evaln; + } else if (n->nif.elsepart) { + n = n->nif.elsepart; + goto evaln; + } + goto success; + case NDEFUN: + defun(n->narg.text, n->narg.next); +success: + status = 0; +setstatus: + exitstatus = status; + break; + } +out: + if (pendingsigs) + dotrap(); + if (flags & EV_EXIT || checkexit & exitstatus) + exraise(EXEXIT); +} + + +#if !defined(__alpha__) || (defined(__GNUC__) && __GNUC__ >= 3) +STATIC +#endif +void evaltreenr(union node *, int) __attribute__ ((alias("evaltree"))); + + +STATIC void +evalloop(union node *n, int flags) +{ + int status; + + loopnest++; + status = 0; + flags &= EV_TESTED; + for (;;) { + int i; + + 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; + } + i = exitstatus; + if (n->type != NWHILE) + i = !i; + if (i != 0) + break; + evaltree(n->nbinary.ch2, flags); + 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; + + setstackmark(&smark); + arglist.lastp = &arglist.list; + for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { + expandarg(argp, &arglist, EXP_FULL | EXP_TILDE | EXP_RECORD); + /* XXX */ + if (evalskip) + goto out; + } + *arglist.lastp = NULL; + + exitstatus = 0; + loopnest++; + flags &= EV_TESTED; + for (sp = arglist.list ; sp ; sp = sp->next) { + setvar(n->nfor.var, sp->text, 0); + evaltree(n->nfor.body, flags); + 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(union node *n, int flags) +{ + union node *cp; + union node *patp; + struct arglist arglist; + struct stackmark smark; + + setstackmark(&smark); + arglist.lastp = &arglist.list; + expandarg(n->ncase.expr, &arglist, EXP_TILDE); + exitstatus = 0; + 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(union node *n, int flags) +{ + struct job *jp; + int backgnd = (n->type == NBACKGND); + int status; + + expredir(n->nredir.redirect); + if (!backgnd && flags & EV_EXIT && !trap[0]) + goto nofork; + INTOFF; + jp = makejob(n, 1); + if (forkshell(jp, n, backgnd) == 0) { + INTON; + flags |= EV_EXIT; + if (backgnd) + flags &=~ EV_TESTED; +nofork: + redirect(n->nredir.redirect, 0); + evaltreenr(n->nredir.n, flags); + /* never returns */ + } + status = 0; + if (! backgnd) + status = waitforjob(jp); + exitstatus = status; + INTON; +} + + + +/* + * 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_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(union node *n, int flags) +{ + 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++; + flags |= EV_EXIT; + 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 (pip[1] >= 0) { + close(pip[0]); + } + if (prevfd > 0) { + dup2(prevfd, 0); + close(prevfd); + } + if (pip[1] > 1) { + dup2(pip[1], 1); + close(pip[1]); + } + evaltreenr(lp->n, flags); + /* never returns */ + } + if (prevfd >= 0) + close(prevfd); + prevfd = pip[0]; + close(pip[1]); + } + if (n->npipe.backgnd == 0) { + 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(union node *n, struct backcmd *result) +{ + int saveherefd; + + result->fd = -1; + result->buf = NULL; + result->nleft = 0; + result->jp = NULL; + if (n == NULL) { + goto out; + } + + saveherefd = herefd; + herefd = -1; + +#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) { + struct ifsregion saveifs; + struct ifsregion *savelastp; + struct nodelist *saveargbackq; + + saveifs = ifsfirst; + savelastp = ifslastp; + saveargbackq = argbackq; + + exitstatus = oexitstatus; + evalcommand(n, EV_BACKCMD, result); + + ifsfirst = saveifs; + ifslastp = savelastp; + argbackq = saveargbackq; + } else +#endif + { + int pip[2]; + struct job *jp; + + 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]); + } + eflag = 0; + evaltreenr(n, EV_EXIT); + /* NOTREACHED */ + } + close(pip[1]); + result->fd = pip[0]; + result->jp = jp; + } + herefd = saveherefd; +out: + TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", + result->fd, result->buf, result->nleft, result->jp)); +} + +static char ** +parse_command_args(char **argv, const char **path) +{ + char *cp, c; + + for (;;) { + cp = *++argv; + if (!cp) + return 0; + if (*cp++ != '-') + break; + if (!(c = *cp++)) + break; + if (c == '-' && !*cp) { + argv++; + break; + } + do { + switch (c) { + case 'p': + *path = defpath; + break; + default: + /* run 'typecmd' for other options */ + return 0; + } + } while ((c = *cp++)); + } + return argv; +} + + + +/* + * Execute a simple command. + */ + +STATIC void +#ifdef notyet +evalcommand(union node *cmd, int flags, struct backcmd *backcmd) +#else +evalcommand(union node *cmd, int flags) +#endif +{ + struct stackmark smark; + union node *argp; + struct arglist arglist; + struct arglist varlist; + char **argv; + int argc; + struct strlist *sp; +#ifdef notyet + int pip[2]; +#endif + struct cmdentry cmdentry; + struct job *jp; + char *lastarg; + const char *path; + int spclbltin; + int execcmd; + int status; + char **nargv; + + /* First expand the arguments. */ + TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); + setstackmark(&smark); + back_exitstatus = 0; + + cmdentry.cmdtype = CMDBUILTIN; + cmdentry.u.cmd = &bltin; + varlist.lastp = &varlist.list; + *varlist.lastp = NULL; + arglist.lastp = &arglist.list; + *arglist.lastp = NULL; + + argc = 0; + for (argp = cmd->ncmd.args; argp; argp = argp->narg.next) { + struct strlist **spp; + + spp = arglist.lastp; + expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); + for (sp = *spp; sp; sp = sp->next) + argc++; + } + + argv = nargv = stalloc(sizeof (char *) * (argc + 1)); + for (sp = arglist.list ; sp ; sp = sp->next) { + TRACE(("evalcommand arg: %s\n", sp->text)); + *nargv++ = sp->text; + } + *nargv = NULL; + + lastarg = NULL; + if (iflag && funcnest == 0 && argc > 0) + lastarg = nargv[-1]; + + preverrout.fd = 2; + expredir(cmd->ncmd.redirect); + status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH|REDIR_SAVEFD2); + + path = vpath.text; + for (argp = cmd->ncmd.assign; argp; argp = argp->narg.next) { + struct strlist **spp; + char *p; + + spp = varlist.lastp; + expandarg(argp, &varlist, EXP_VARTILDE); + + /* + * Modify the command lookup path, if a PATH= assignment + * is present + */ + p = (*spp)->text; + if (varequal(p, path)) + path = p; + } + + /* Print the command if xflag is set. */ + if (xflag) { + struct output *out; + int sep; + + out = &preverrout; + outstr(expandstr(ps4val()), out); + sep = 0; + sep = eprintlist(out, varlist.list, sep); + eprintlist(out, arglist.list, sep); + outcslow('\n', out); +#ifdef FLUSHERR + flushout(out); +#endif + } + + execcmd = 0; + spclbltin = -1; + + /* Now locate the command. */ + if (argc) { + const char *oldpath; + int cmd_flag = DO_ERR; + + path += 5; + oldpath = path; + for (;;) { + find_command(argv[0], &cmdentry, cmd_flag, path); + if (cmdentry.cmdtype == CMDUNKNOWN) { + status = 127; +#ifdef FLUSHERR + flushout(&errout); +#endif + goto bail; + } + + /* implement bltin and command here */ + if (cmdentry.cmdtype != CMDBUILTIN) + break; + if (spclbltin < 0) + spclbltin = + cmdentry.u.cmd->flags & + BUILTIN_SPECIAL + ; + if (cmdentry.u.cmd == EXECCMD) + execcmd++; + if (cmdentry.u.cmd != COMMANDCMD) + break; + + path = oldpath; + nargv = parse_command_args(argv, &path); + if (!nargv) + break; + argc -= nargv - argv; + argv = nargv; + cmd_flag |= DO_NOFUNC; + } + } + + if (status) { + /* We have a redirection error. */ + if (spclbltin > 0) + exraise(EXERROR); +bail: + exitstatus = status; + goto out; + } + + /* Execute the command. */ + switch (cmdentry.cmdtype) { + default: + /* Fork off a child process if necessary. */ + if (!(flags & EV_EXIT) || trap[0]) { + INTOFF; + jp = makejob(cmd, 1); + if (forkshell(jp, cmd, FORK_FG) != 0) { + exitstatus = waitforjob(jp); + INTON; + break; + } + FORCEINTON; + } + listsetvar(varlist.list, VEXPORT|VSTACK); + shellexec(argv, path, cmdentry.u.index); + /* NOTREACHED */ + + case CMDBUILTIN: + cmdenviron = varlist.list; + if (cmdenviron) { + struct strlist *list = cmdenviron; + int i = VNOSET; + if (spclbltin > 0 || argc == 0) { + i = 0; + if (execcmd && argc > 1) + i = VEXPORT; + } + listsetvar(list, i); + } + if (evalbltin(cmdentry.u.cmd, argc, argv)) { + int status; + int i, j; + + i = exception; + if (i == EXEXIT) + goto raise; + + status = 2; + j = 0; + if (i == EXINT) + j = SIGINT; + if (i == EXSIG) + j = pendingsigs; + if (j) + status = j + 128; + exitstatus = status; + + if (i == EXINT || spclbltin > 0) { +raise: + longjmp(handler->loc, 1); + } + FORCEINTON; + } + break; + + case CMDFUNCTION: + listsetvar(varlist.list, 0); + if (evalfun(cmdentry.u.func, argc, argv, flags)) + goto raise; + break; + } + +out: + popredir(execcmd); + if (lastarg) + /* dsl: I think this is intended to be used to support + * '_' in 'vi' command mode during line editing... + * However I implemented that within libedit itself. + */ + setvar("_", lastarg, 0); + popstackmark(&smark); +} + +STATIC int +evalbltin(const struct builtincmd *cmd, int argc, char **argv) { + char *volatile savecmdname; + struct jmploc *volatile savehandler; + struct jmploc jmploc; + int i; + + savecmdname = commandname; + if ((i = setjmp(jmploc.loc))) + goto cmddone; + savehandler = handler; + handler = &jmploc; + commandname = argv[0]; + argptr = argv + 1; + optptr = NULL; /* initialize nextopt */ + exitstatus = (*cmd->builtin)(argc, argv); + flushall(); +cmddone: + exitstatus |= outerr(out1); + freestdout(); + commandname = savecmdname; + exsig = 0; + handler = savehandler; + + return i; +} + +STATIC int +evalfun(struct funcnode *func, int argc, char **argv, int flags) +{ + volatile struct shparam saveparam; + struct localvar *volatile savelocalvars; + struct jmploc *volatile savehandler; + struct jmploc jmploc; + int e; + + saveparam = shellparam; + savelocalvars = localvars; + if ((e = setjmp(jmploc.loc))) { + goto funcdone; + } + INTOFF; + savehandler = handler; + handler = &jmploc; + localvars = NULL; + shellparam.malloc = 0; + func->count++; + INTON; + shellparam.nparam = argc - 1; + shellparam.p = argv + 1; + shellparam.optind = 1; + shellparam.optoff = -1; + funcnest++; + evaltree(&func->n, flags & EV_TESTED); + funcnest--; +funcdone: + INTOFF; + freefunc(func); + poplocalvars(); + localvars = savelocalvars; + freeparam(&shellparam); + shellparam = saveparam; + handler = savehandler; + INTON; + if (evalskip == SKIPFUNC) { + evalskip = 0; + skipcount = 0; + } + return e; +} + + +/* + * 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->type == NCMD && n->ncmd.args) + if (goodname(n->ncmd.args->narg.text)) + find_command(n->ncmd.args->narg.text, &entry, 0, + pathval()); +} + + + +/* + * Builtin commands. Builtin commands whose functions are closely + * tied to evaluation are implemented here. + */ + +/* + * No command given. + */ + +STATIC 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(illnum, argv[1]); + if (n > loopnest) + n = loopnest; + if (n > 0) { + evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; + skipcount = n; + } + return 0; +} + + +/* + * The return command. + */ + +int +returncmd(int argc, char **argv) +{ + int ret = argc > 1 ? number(argv[1]) : exitstatus; + + if (funcnest) { + evalskip = SKIPFUNC; + skipcount = 1; + return ret; + } + else { + /* Do what ksh does; skip the rest of the file */ + evalskip = SKIPFILE; + skipcount = 1; + 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) { + iflag = 0; /* exit on error */ + mflag = 0; + optschanged(); + shellexec(argv + 1, pathval(), 0); + } + return 0; +} + + +STATIC int +eprintlist(struct output *out, struct strlist *sp, int sep) +{ + while (sp) { + const char *p; + + p = " %s" + (1 - sep); + sep |= 1; + outfmt(out, p, sp->text); + sp = sp->next; + } + + return sep; +} |