/*- * 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. * * $Id: eval.c,v 1.5 1996/09/01 10:19:57 peter Exp $ */ #ifndef lint static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; #endif /* not lint */ #include #include /* * 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) { /* don't bomb out on "set -e; false && true" */ flags |= EV_TESTED; 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 { static const char PATH[] = "PATH="; char *path = pathval(); /* * Modify the command lookup path, if a PATH= assignment * is present */ for (sp = varlist.list ; sp ; sp = sp->next) if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) path = sp->text + sizeof(PATH) - 1; find_command(argv[0], &cmdentry, 1, path); if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ exitstatus = 1; 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 = 1; 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, pathval()); } /* * 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; }