/* $NetBSD: eval.c,v 1.87 2006/05/13 19:47:22 christos 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. 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 #ifndef lint #if 0 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; #else __RCSID("$NetBSD: eval.c,v 1.87 2006/05/13 19:47:22 christos Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #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" #include "main.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 */ 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 *); STATIC void evalcommand(union node *, int, struct backcmd *); STATIC void prehash(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 static int sh_pipe(int fds[2]) { int nfd; if (pipe(fds)) return -1; if (fds[0] < 3) { nfd = fcntl(fds[0], F_DUPFD, 3); if (nfd != -1) { close(fds[0]); fds[0] = nfd; } } if (fds[1] < 3) { nfd = fcntl(fds[1], F_DUPFD, 3); if (nfd != -1) { close(fds[1]); fds[1] = nfd; } } return 0; } /* * 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 (;;) { while (*p) STPUTC(*p++, concat); if ((p = *ap++) == NULL) break; STPUTC(' ', concat); } STPUTC('\0', concat); p = grabstackstr(concat); } evalstring(p, EV_TESTED); } return exitstatus; } /* * Execute a command or commands contained in a string. */ void evalstring(char *s, int flag) { union node *n; struct stackmark smark; setstackmark(&smark); setinputstring(s, 1); while ((n = parsecmd(0)) != NEOF) { evaltree(n, flag); popstackmark(&smark); } popfile(); popstackmark(&smark); } /* * Evaluate a parse tree. The value is left in the global variable * exitstatus. */ void evaltree(union node *n, int flags) { if (n == NULL) { TRACE(("evaltree(NULL) called\n")); exitstatus = 0; 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) { case NSEMI: evaltree(n->nbinary.ch1, flags & EV_TESTED); if (evalskip) goto out; evaltree(n->nbinary.ch2, flags); break; case NAND: evaltree(n->nbinary.ch1, EV_TESTED); if (evalskip || exitstatus != 0) 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: { evaltree(n->nif.test, EV_TESTED); if (evalskip) goto out; if (exitstatus == 0) evaltree(n->nif.ifpart, flags); else if (n->nif.elsepart) evaltree(n->nif.elsepart, flags); else exitstatus = 0; break; } case NWHILE: case NUNTIL: evalloop(n, flags); break; case NFOR: evalfor(n, flags); 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) != 0) exitshell(exitstatus); } STATIC void evalloop(union node *n, int flags) { 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, flags & EV_TESTED); 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; int status = 0; setstackmark(&smark); arglist.lastp = &arglist.list; for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); if (evalskip) goto out; } *arglist.lastp = NULL; loopnest++; for (sp = arglist.list ; sp ; sp = sp->next) { setvar(n->nfor.var, sp->text, 0); evaltree(n->nfor.body, flags & EV_TESTED); status = exitstatus; if (evalskip) { if (evalskip == SKIPCONT && --skipcount <= 0) { evalskip = 0; continue; } if (evalskip == SKIPBREAK && --skipcount <= 0) evalskip = 0; break; } } loopnest--; exitstatus = status; out: popstackmark(&smark); } STATIC void evalcase(union node *n, int flags) { union node *cp; union node *patp; struct arglist arglist; struct stackmark smark; int status = 0; setstackmark(&smark); arglist.lastp = &arglist.list; 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); status = exitstatus; } goto out; } } } out: exitstatus = status; 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); expredir(n->nredir.redirect); INTOFF; jp = makejob(n, 1); if (forkshell(jp, n, backgnd ? FORK_BG : FORK_FG) == 0) { INTON; if (backgnd) flags &=~ EV_TESTED; redirect(n->nredir.redirect, 0); /* never returns */ evaltree(n->nredir.n, flags | EV_EXIT); } if (! backgnd) exitstatus = waitforjob(jp); 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) { 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 (sh_pipe(pip) < 0) { if (prevfd >= 0) close(prevfd); error("Pipe call failed"); } } if (forkshell(jp, lp->n, n->npipe.backgnd ? FORK_BG : FORK_FG) == 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]); } 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 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) { goto out; } #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) { exitstatus = oexitstatus; evalcommand(n, EV_BACKCMD, result); } else #endif { INTOFF; if (sh_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; evaltree(n, EV_EXIT); /* NOTREACHED */ } close(pip[1]); result->fd = pip[0]; result->jp = jp; INTON; } 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)); } static const char * syspath(void) { static char *sys_path = NULL; static int mib[] = {CTL_USER, USER_CS_PATH}; static char def_path[] = "PATH=/usr/bin:/bin:/usr/sbin:/sbin"; size_t len; if (sys_path == NULL) { if (sysctl(mib, 2, 0, &len, 0, 0) != -1 && (sys_path = ckmalloc(len + 5)) != NULL && sysctl(mib, 2, sys_path + 5, &len, 0, 0) != -1) { memcpy(sys_path, "PATH=", 5); } else { ckfree(sys_path); /* something to keep things happy */ sys_path = def_path; } } return sys_path; } static int parse_command_args(int argc, char **argv, int *use_syspath) { int sv_argc = argc; char *cp, c; *use_syspath = 0; for (;;) { argv++; if (--argc == 0) break; cp = *argv; if (*cp++ != '-') break; if (*cp == '-' && cp[1] == 0) { argv++; argc--; break; } while ((c = *cp++)) { switch (c) { case 'p': *use_syspath = 1; break; default: /* run 'typecmd' for other options */ return 0; } } } return sv_argc - argc; } int vforked = 0; /* * Execute a simple command. */ STATIC void evalcommand(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 = NULL; char *volatile savecmdname; volatile struct shparam saveparam; struct localvar *volatile savelocalvars; volatile int e; char *lastarg; const char *path = pathval(); volatile int temp_path; #if __GNUC__ /* Avoid longjmp clobbering */ (void) &argv; (void) &argc; (void) &lastarg; (void) &flags; #endif vforked = 0; /* First expand the arguments. */ TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); setstackmark(&smark); back_exitstatus = 0; arglist.lastp = &arglist.list; varflag = 1; /* Expand arguments, ignoring the initial 'name=value' ones */ 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 == '=') continue; } expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); varflag = 0; } *arglist.lastp = NULL; expredir(cmd->ncmd.redirect); /* Now do the initial 'name=value' ones we skipped above */ varlist.lastp = &varlist.list; for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { char *p = argp->narg.text; if (!is_name(*p)) break; do p++; while (is_in_name(*p)); if (*p != '=') break; expandarg(argp, &varlist, EXP_VARTILDE); } *varlist.lastp = NULL; 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) { char sep = 0; out2str(ps4val()); for (sp = varlist.list ; sp ; sp = sp->next) { if (sep != 0) outc(sep, &errout); out2str(sp->text); sep = ' '; } for (sp = arglist.list ; sp ; sp = sp->next) { if (sep != 0) outc(sep, &errout); out2str(sp->text); sep = ' '; } outc('\n', &errout); flushout(&errout); } /* Now locate the command. */ if (argc == 0) { cmdentry.cmdtype = CMDSPLBLTIN; cmdentry.u.bltin = bltincmd; } else { static const char PATH[] = "PATH="; int cmd_flags = DO_ERR; /* * 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; do { int argsused, use_syspath; find_command(argv[0], &cmdentry, cmd_flags, path); if (cmdentry.cmdtype == CMDUNKNOWN) { exitstatus = 127; flushout(&errout); goto out; } /* implement the 'command' builtin here */ if (cmdentry.cmdtype != CMDBUILTIN || cmdentry.u.bltin != bltincmd) break; cmd_flags |= DO_NOFUNC; argsused = parse_command_args(argc, argv, &use_syspath); if (argsused == 0) { /* use 'type' builting to display info */ cmdentry.u.bltin = typecmd; break; } argc -= argsused; argv += argsused; if (use_syspath) path = syspath() + 5; } while (argc != 0); if (cmdentry.cmdtype == CMDSPLBLTIN && cmd_flags & DO_NOFUNC) /* posix mandates that 'command ' act as if was a normal builtin */ cmdentry.cmdtype = CMDBUILTIN; } /* 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.cmdtype != CMDSPLBLTIN) || cmdentry.u.bltin == dotcmd || cmdentry.u.bltin == evalcmd))) { INTOFF; jp = makejob(cmd, 1); mode = cmd->ncmd.backgnd; if (flags & EV_BACKCMD) { mode = FORK_NOJOB; if (sh_pipe(pip) < 0) error("Pipe call failed"); } #ifdef DO_SHAREDVFORK /* It is essential that if DO_SHAREDVFORK is defined that the * child's address space is actually shared with the parent as * we rely on this. */ if (cmdentry.cmdtype == CMDNORMAL) { pid_t pid; savelocalvars = localvars; localvars = NULL; vforked = 1; switch (pid = vfork()) { case -1: TRACE(("Vfork failed, errno=%d\n", errno)); INTON; error("Cannot vfork"); break; case 0: /* Make sure that exceptions only unwind to * after the vfork(2) */ if (setjmp(jmploc.loc)) { if (exception == EXSHELLPROC) { /* We can't progress with the vfork, * so, set vforked = 2 so the parent * knows, and _exit(); */ vforked = 2; _exit(0); } else { _exit(exerrno); } } savehandler = handler; handler = &jmploc; listmklocal(varlist.list, VEXPORT | VNOFUNC); forkchild(jp, cmd, mode, vforked); break; default: handler = savehandler; /* restore from vfork(2) */ poplocalvars(); localvars = savelocalvars; if (vforked == 2) { vforked = 0; (void)waitpid(pid, NULL, 0); /* We need to progress in a normal fork fashion */ goto normal_fork; } vforked = 0; forkparent(jp, cmd, mode, pid); goto parent; } } else { normal_fork: #endif if (forkshell(jp, cmd, mode) != 0) goto parent; /* at end of routine */ FORCEINTON; #ifdef DO_SHAREDVFORK } #endif if (flags & EV_BACKCMD) { if (!vforked) { 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. */ switch (cmdentry.cmdtype) { case CMDFUNCTION: #ifdef DEBUG trputs("Shell function: "); trargs(argv); #endif redirect(cmd->ncmd.redirect, REDIR_PUSH); saveparam = shellparam; shellparam.malloc = 0; shellparam.reset = 1; 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((volatile struct shparam *) &saveparam); } else { freeparam(&shellparam); shellparam = saveparam; } poplocalvars(); localvars = savelocalvars; handler = savehandler; longjmp(handler->loc, 1); } savehandler = handler; handler = &jmploc; listmklocal(varlist.list, 0); /* stop shell blowing its stack */ if (++funcnest > 1000) error("too many nested function calls"); evaltree(cmdentry.u.func, flags & EV_TESTED); 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); break; case CMDBUILTIN: case CMDSPLBLTIN: #ifdef DEBUG trputs("builtin command: "); trargs(argv); #endif mode = (cmdentry.u.bltin == execcmd) ? 0 : REDIR_PUSH; if (flags == EV_BACKCMD) { memout.nleft = 0; memout.nextc = memout.buf; memout.bufsize = 64; mode |= REDIR_BACKQ; } e = -1; savehandler = handler; savecmdname = commandname; handler = &jmploc; if (!setjmp(jmploc.loc)) { /* We need to ensure the command hash table isn't * corruped by temporary PATH assignments. * However we must ensure the 'local' command works! */ if (path != pathval() && (cmdentry.u.bltin == hashcmd || cmdentry.u.bltin == typecmd)) { savelocalvars = localvars; localvars = 0; mklocal(path - 5 /* PATH= */, 0); temp_path = 1; } else temp_path = 0; redirect(cmd->ncmd.redirect, mode); /* exec is a special builtin, but needs this list... */ cmdenviron = varlist.list; /* we must check 'readonly' flag for all builtins */ listsetvar(varlist.list, cmdentry.cmdtype == CMDSPLBLTIN ? 0 : VNOSET); commandname = argv[0]; /* initialize nextopt */ argptr = argv + 1; optptr = NULL; /* and getopt */ optreset = 1; optind = 1; exitstatus = cmdentry.u.bltin(argc, argv); } else { e = exception; exitstatus = e == EXINT ? SIGINT + 128 : e == EXEXEC ? exerrno : 2; } handler = savehandler; flushall(); out1 = &output; out2 = &errout; freestdout(); if (temp_path) { poplocalvars(); localvars = savelocalvars; } cmdenviron = NULL; if (e != EXSHELLPROC) { commandname = savecmdname; if (flags & EV_EXIT) exitshell(exitstatus); } if (e != -1) { if ((e != EXERROR && e != EXEXEC) || cmdentry.cmdtype == CMDSPLBLTIN) exraise(e); FORCEINTON; } if (cmdentry.u.bltin != execcmd) popredir(); if (flags == EV_BACKCMD) { backcmd->buf = memout.buf; backcmd->nleft = memout.nextc - memout.buf; memout.buf = NULL; } break; default: #ifdef DEBUG trputs("normal command: "); trargs(argv); #endif clearredir(vforked); redirect(cmd->ncmd.redirect, vforked ? REDIR_VFORK : 0); if (!vforked) for (sp = varlist.list ; sp ; sp = sp->next) setvareq(sp->text, VEXPORT|VSTACK); envp = environment(); shellexec(argv, envp, path, cmdentry.u.index, vforked); break; } goto out; parent: /* parent process gets here (if we forked) */ if (mode == FORK_FG) { /* argument to fork */ exitstatus = waitforjob(jp); } else if (mode == FORK_NOJOB) { backcmd->fd = pip[0]; close(pip[1]); backcmd->jp = jp; } FORCEINTON; out: 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); if (eflag && exitstatus && !(flags & EV_TESTED)) exitshell(exitstatus); } /* * 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 && 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. */ 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 > 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) { 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, 0); } return 0; } static int conv_time(clock_t ticks, char *seconds, size_t l) { static clock_t tpm = 0; clock_t mins; int i; if (!tpm) tpm = sysconf(_SC_CLK_TCK) * 60; mins = ticks / tpm; snprintf(seconds, l, "%.4f", (ticks - mins * tpm) * 60.0 / tpm ); if (seconds[0] == '6' && seconds[1] == '0') { /* 59.99995 got rounded up... */ mins++; strlcpy(seconds, "0.0", l); return mins; } /* suppress trailing zeros */ i = strlen(seconds) - 1; for (; seconds[i] == '0' && seconds[i - 1] != '.'; i--) seconds[i] = 0; return mins; } int timescmd(int argc, char **argv) { struct tms tms; int u, s, cu, cs; char us[8], ss[8], cus[8], css[8]; nextopt(""); times(&tms); u = conv_time(tms.tms_utime, us, sizeof(us)); s = conv_time(tms.tms_stime, ss, sizeof(ss)); cu = conv_time(tms.tms_cutime, cus, sizeof(cus)); cs = conv_time(tms.tms_cstime, css, sizeof(css)); outfmt(out1, "%dm%ss %dm%ss\n%dm%ss %dm%ss\n", u, us, s, ss, cu, cus, cs, css); return 0; }