eval.c

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	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;
	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 <splbltin>' act as if
			   <splbltin> 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 */
#ifndef __linux__
			optreset = 1;
#endif
			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->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;

	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;
}