main.c revision 213811 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34static char const copyright[] =
35"@(#) Copyright (c) 1991, 1993\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#ifndef lint
40#if 0
41static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/28/95";
42#endif
43#endif /* not lint */
44#include <sys/cdefs.h>
45__FBSDID("$FreeBSD: head/bin/sh/main.c 213811 2010-10-13 22:18:03Z obrien $");
46
47#include <stdio.h>
48#include <signal.h>
49#include <sys/stat.h>
50#include <unistd.h>
51#include <fcntl.h>
52#include <locale.h>
53#include <errno.h>
54
55#include "shell.h"
56#include "main.h"
57#include "mail.h"
58#include "options.h"
59#include "output.h"
60#include "parser.h"
61#include "nodes.h"
62#include "expand.h"
63#include "eval.h"
64#include "jobs.h"
65#include "input.h"
66#include "trap.h"
67#include "var.h"
68#include "show.h"
69#include "memalloc.h"
70#include "error.h"
71#include "init.h"
72#include "mystring.h"
73#include "exec.h"
74#include "cd.h"
75
76int rootpid;
77int rootshell;
78struct jmploc main_handler;
79
80static void read_profile(const char *);
81static char *find_dot_file(char *);
82
83/*
84 * Main routine.  We initialize things, parse the arguments, execute
85 * profiles if we're a login shell, and then call cmdloop to execute
86 * commands.  The setjmp call sets up the location to jump to when an
87 * exception occurs.  When an exception occurs the variable "state"
88 * is used to figure out how far we had gotten.
89 */
90
91int
92main(int argc, char *argv[])
93{
94	struct stackmark smark;
95	volatile int state;
96	char *shinit;
97
98	(void) setlocale(LC_ALL, "");
99	state = 0;
100	if (setjmp(main_handler.loc)) {
101		/*
102		 * When a shell procedure is executed, we raise the
103		 * exception EXSHELLPROC to clean up before executing
104		 * the shell procedure.
105		 */
106		switch (exception) {
107		case EXSHELLPROC:
108			rootpid = getpid();
109			rootshell = 1;
110			minusc = NULL;
111			state = 3;
112			break;
113
114		case EXEXEC:
115			exitstatus = exerrno;
116			break;
117
118		case EXERROR:
119			exitstatus = 2;
120			break;
121
122		default:
123			break;
124		}
125
126		if (exception != EXSHELLPROC) {
127		    if (state == 0 || iflag == 0 || ! rootshell)
128			    exitshell(exitstatus);
129		}
130		reset();
131		if (exception == EXINT) {
132			out2c('\n');
133			flushout(&errout);
134		}
135		popstackmark(&smark);
136		FORCEINTON;				/* enable interrupts */
137		if (state == 1)
138			goto state1;
139		else if (state == 2)
140			goto state2;
141		else if (state == 3)
142			goto state3;
143		else
144			goto state4;
145	}
146	handler = &main_handler;
147#ifdef DEBUG
148	opentrace();
149	trputs("Shell args:  ");  trargs(argv);
150#endif
151	rootpid = getpid();
152	rootshell = 1;
153	init();
154	setstackmark(&smark);
155	procargs(argc, argv);
156	pwd_init(iflag);
157	if (iflag)
158		chkmail(1);
159	if (argv[0] && argv[0][0] == '-') {
160		state = 1;
161		read_profile("/etc/profile");
162state1:
163		state = 2;
164		if (privileged == 0)
165			read_profile(".profile");
166		else
167			read_profile("/etc/suid_profile");
168	}
169state2:
170	state = 3;
171	if (!privileged && iflag) {
172		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
173			state = 3;
174			read_profile(shinit);
175		}
176	}
177state3:
178	state = 4;
179	if (minusc) {
180		evalstring(minusc, sflag ? 0 : EV_EXIT);
181	}
182	if (sflag || minusc == NULL) {
183state4:	/* XXX ??? - why isn't this before the "if" statement */
184		cmdloop(1);
185	}
186	exitshell(exitstatus);
187	/*NOTREACHED*/
188	return 0;
189}
190
191
192/*
193 * Read and execute commands.  "Top" is nonzero for the top level command
194 * loop; it turns on prompting if the shell is interactive.
195 */
196
197void
198cmdloop(int top)
199{
200	union node *n;
201	struct stackmark smark;
202	int inter;
203	int numeof = 0;
204
205	TRACE(("cmdloop(%d) called\n", top));
206	setstackmark(&smark);
207	for (;;) {
208		if (pendingsigs)
209			dotrap();
210		inter = 0;
211		if (iflag && top) {
212			inter++;
213			showjobs(1, SHOWJOBS_DEFAULT);
214			chkmail(0);
215			flushout(&output);
216		}
217		n = parsecmd(inter);
218		/* showtree(n); DEBUG */
219		if (n == NEOF) {
220			if (!top || numeof >= 50)
221				break;
222			if (!stoppedjobs()) {
223				if (!Iflag)
224					break;
225				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
226			}
227			numeof++;
228		} else if (n != NULL && nflag == 0) {
229			job_warning = (job_warning == 2) ? 1 : 0;
230			numeof = 0;
231			evaltree(n, 0);
232		}
233		popstackmark(&smark);
234		setstackmark(&smark);
235		if (evalskip != 0) {
236			if (evalskip == SKIPFILE)
237				evalskip = 0;
238			break;
239		}
240	}
241	popstackmark(&smark);
242}
243
244
245
246/*
247 * Read /etc/profile or .profile.  Return on error.
248 */
249
250static void
251read_profile(const char *name)
252{
253	int fd;
254
255	INTOFF;
256	if ((fd = open(name, O_RDONLY)) >= 0)
257		setinputfd(fd, 1);
258	INTON;
259	if (fd < 0)
260		return;
261	cmdloop(0);
262	popfile();
263}
264
265
266
267/*
268 * Read a file containing shell functions.
269 */
270
271void
272readcmdfile(const char *name)
273{
274	int fd;
275
276	INTOFF;
277	if ((fd = open(name, O_RDONLY)) >= 0)
278		setinputfd(fd, 1);
279	else
280		error("Can't open %s: %s", name, strerror(errno));
281	INTON;
282	cmdloop(0);
283	popfile();
284}
285
286
287
288/*
289 * Take commands from a file.  To be compatible we should do a path
290 * search for the file, which is necessary to find sub-commands.
291 */
292
293
294static char *
295find_dot_file(char *basename)
296{
297	static char localname[FILENAME_MAX+1];
298	char *fullname;
299	const char *path = pathval();
300	struct stat statb;
301
302	/* don't try this for absolute or relative paths */
303	if( strchr(basename, '/'))
304		return basename;
305
306	while ((fullname = padvance(&path, basename)) != NULL) {
307		strcpy(localname, fullname);
308		stunalloc(fullname);
309		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode))
310			return localname;
311	}
312	return basename;
313}
314
315int
316dotcmd(int argc, char **argv)
317{
318	char *filename, *fullname;
319
320	if (argc < 2)
321		error("missing filename");
322
323	exitstatus = 0;
324
325	/*
326	 * Because we have historically not supported any options,
327	 * only treat "--" specially.
328	 */
329	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
330
331	fullname = find_dot_file(filename);
332	setinputfile(fullname, 1);
333	commandname = fullname;
334	cmdloop(0);
335	popfile();
336	return exitstatus;
337}
338
339
340int
341exitcmd(int argc, char **argv)
342{
343	if (stoppedjobs())
344		return 0;
345	if (argc > 1)
346		exitstatus = number(argv[1]);
347	else
348		exitstatus = oexitstatus;
349	exitshell(exitstatus);
350	/*NOTREACHED*/
351	return 0;
352}
353