xref: /freebsd/bin/sh/main.c (revision cded07a8783dedbb0634ebde78764f935f26467d)
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
34 static 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
41 static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/28/95";
42 #endif
43 #endif /* not lint */
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
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 
76 int rootpid;
77 int rootshell;
78 struct jmploc main_handler;
79 
80 static void read_profile(const char *);
81 static 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 
91 int
92 main(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 			out2fmt_flush("\n");
133 		popstackmark(&smark);
134 		FORCEINTON;				/* enable interrupts */
135 		if (state == 1)
136 			goto state1;
137 		else if (state == 2)
138 			goto state2;
139 		else if (state == 3)
140 			goto state3;
141 		else
142 			goto state4;
143 	}
144 	handler = &main_handler;
145 #ifdef DEBUG
146 	opentrace();
147 	trputs("Shell args:  ");  trargs(argv);
148 #endif
149 	rootpid = getpid();
150 	rootshell = 1;
151 	init();
152 	setstackmark(&smark);
153 	procargs(argc, argv);
154 	pwd_init(iflag);
155 	if (iflag)
156 		chkmail(1);
157 	if (argv[0] && argv[0][0] == '-') {
158 		state = 1;
159 		read_profile("/etc/profile");
160 state1:
161 		state = 2;
162 		if (privileged == 0)
163 			read_profile(".profile");
164 		else
165 			read_profile("/etc/suid_profile");
166 	}
167 state2:
168 	state = 3;
169 	if (!privileged && iflag) {
170 		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
171 			state = 3;
172 			read_profile(shinit);
173 		}
174 	}
175 state3:
176 	state = 4;
177 	if (minusc) {
178 		evalstring(minusc, sflag ? 0 : EV_EXIT);
179 	}
180 	if (sflag || minusc == NULL) {
181 state4:	/* XXX ??? - why isn't this before the "if" statement */
182 		cmdloop(1);
183 	}
184 	exitshell(exitstatus);
185 	/*NOTREACHED*/
186 	return 0;
187 }
188 
189 
190 /*
191  * Read and execute commands.  "Top" is nonzero for the top level command
192  * loop; it turns on prompting if the shell is interactive.
193  */
194 
195 void
196 cmdloop(int top)
197 {
198 	union node *n;
199 	struct stackmark smark;
200 	int inter;
201 	int numeof = 0;
202 
203 	TRACE(("cmdloop(%d) called\n", top));
204 	setstackmark(&smark);
205 	for (;;) {
206 		if (pendingsigs)
207 			dotrap();
208 		inter = 0;
209 		if (iflag && top) {
210 			inter++;
211 			showjobs(1, SHOWJOBS_DEFAULT);
212 			chkmail(0);
213 			flushout(&output);
214 		}
215 		n = parsecmd(inter);
216 		/* showtree(n); DEBUG */
217 		if (n == NEOF) {
218 			if (!top || numeof >= 50)
219 				break;
220 			if (!stoppedjobs()) {
221 				if (!Iflag)
222 					break;
223 				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
224 			}
225 			numeof++;
226 		} else if (n != NULL && nflag == 0) {
227 			job_warning = (job_warning == 2) ? 1 : 0;
228 			numeof = 0;
229 			evaltree(n, 0);
230 		}
231 		popstackmark(&smark);
232 		setstackmark(&smark);
233 		if (evalskip != 0) {
234 			if (evalskip == SKIPFILE)
235 				evalskip = 0;
236 			break;
237 		}
238 	}
239 	popstackmark(&smark);
240 }
241 
242 
243 
244 /*
245  * Read /etc/profile or .profile.  Return on error.
246  */
247 
248 static void
249 read_profile(const char *name)
250 {
251 	int fd;
252 
253 	INTOFF;
254 	if ((fd = open(name, O_RDONLY)) >= 0)
255 		setinputfd(fd, 1);
256 	INTON;
257 	if (fd < 0)
258 		return;
259 	cmdloop(0);
260 	popfile();
261 }
262 
263 
264 
265 /*
266  * Read a file containing shell functions.
267  */
268 
269 void
270 readcmdfile(const char *name)
271 {
272 	int fd;
273 
274 	INTOFF;
275 	if ((fd = open(name, O_RDONLY)) >= 0)
276 		setinputfd(fd, 1);
277 	else
278 		error("Can't open %s: %s", name, strerror(errno));
279 	INTON;
280 	cmdloop(0);
281 	popfile();
282 }
283 
284 
285 
286 /*
287  * Take commands from a file.  To be compatible we should do a path
288  * search for the file, which is necessary to find sub-commands.
289  */
290 
291 
292 static char *
293 find_dot_file(char *basename)
294 {
295 	static char localname[FILENAME_MAX+1];
296 	char *fullname;
297 	const char *path = pathval();
298 	struct stat statb;
299 
300 	/* don't try this for absolute or relative paths */
301 	if( strchr(basename, '/'))
302 		return basename;
303 
304 	while ((fullname = padvance(&path, basename)) != NULL) {
305 		strcpy(localname, fullname);
306 		stunalloc(fullname);
307 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode))
308 			return localname;
309 	}
310 	return basename;
311 }
312 
313 int
314 dotcmd(int argc, char **argv)
315 {
316 	char *filename, *fullname;
317 
318 	if (argc < 2)
319 		error("missing filename");
320 
321 	exitstatus = 0;
322 
323 	/*
324 	 * Because we have historically not supported any options,
325 	 * only treat "--" specially.
326 	 */
327 	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
328 
329 	fullname = find_dot_file(filename);
330 	setinputfile(fullname, 1);
331 	commandname = fullname;
332 	cmdloop(0);
333 	popfile();
334 	return exitstatus;
335 }
336 
337 
338 int
339 exitcmd(int argc, char **argv)
340 {
341 	if (stoppedjobs())
342 		return 0;
343 	if (argc > 1)
344 		exitstatus = number(argv[1]);
345 	else
346 		exitstatus = oexitstatus;
347 	exitshell(exitstatus);
348 	/*NOTREACHED*/
349 	return 0;
350 }
351