xref: /freebsd/bin/sh/main.c (revision 40a8ac8f62b535d30349faf28cf47106b7041b83)
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 "mystring.h"
72 #include "exec.h"
73 #include "cd.h"
74 #include "redir.h"
75 #include "builtins.h"
76 
77 int rootpid;
78 int rootshell;
79 struct jmploc main_handler;
80 int localeisutf8, initial_localeisutf8;
81 
82 static void reset(void);
83 static void cmdloop(int);
84 static void read_profile(const char *);
85 static char *find_dot_file(char *);
86 
87 /*
88  * Main routine.  We initialize things, parse the arguments, execute
89  * profiles if we're a login shell, and then call cmdloop to execute
90  * commands.  The setjmp call sets up the location to jump to when an
91  * exception occurs.  When an exception occurs the variable "state"
92  * is used to figure out how far we had gotten.
93  */
94 
95 int
96 main(int argc, char *argv[])
97 {
98 	struct stackmark smark, smark2;
99 	volatile int state;
100 	char *shinit;
101 
102 	(void) setlocale(LC_ALL, "");
103 	initcharset();
104 	state = 0;
105 	if (setjmp(main_handler.loc)) {
106 		switch (exception) {
107 		case EXEXEC:
108 			exitstatus = exerrno;
109 			break;
110 
111 		case EXERROR:
112 			exitstatus = 2;
113 			break;
114 
115 		default:
116 			break;
117 		}
118 
119 		if (state == 0 || iflag == 0 || ! rootshell ||
120 		    exception == EXEXIT)
121 			exitshell(exitstatus);
122 		reset();
123 		if (exception == EXINT)
124 			out2fmt_flush("\n");
125 		popstackmark(&smark);
126 		FORCEINTON;				/* enable interrupts */
127 		if (state == 1)
128 			goto state1;
129 		else if (state == 2)
130 			goto state2;
131 		else if (state == 3)
132 			goto state3;
133 		else
134 			goto state4;
135 	}
136 	handler = &main_handler;
137 #ifdef DEBUG
138 	opentrace();
139 	trputs("Shell args:  ");  trargs(argv);
140 #endif
141 	rootpid = getpid();
142 	rootshell = 1;
143 	INTOFF;
144 	initvar();
145 	setstackmark(&smark);
146 	setstackmark(&smark2);
147 	procargs(argc, argv);
148 	pwd_init(iflag);
149 	INTON;
150 	if (iflag)
151 		chkmail(1);
152 	if (argv[0] && argv[0][0] == '-') {
153 		state = 1;
154 		read_profile("/etc/profile");
155 state1:
156 		state = 2;
157 		if (privileged == 0)
158 			read_profile("${HOME-}/.profile");
159 		else
160 			read_profile("/etc/suid_profile");
161 	}
162 state2:
163 	state = 3;
164 	if (!privileged && iflag) {
165 		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
166 			state = 3;
167 			read_profile(shinit);
168 		}
169 	}
170 state3:
171 	state = 4;
172 	popstackmark(&smark2);
173 	if (minusc) {
174 		evalstring(minusc, sflag ? 0 : EV_EXIT);
175 	}
176 state4:
177 	if (sflag || minusc == NULL) {
178 		cmdloop(1);
179 	}
180 	exitshell(exitstatus);
181 	/*NOTREACHED*/
182 	return 0;
183 }
184 
185 static void
186 reset(void)
187 {
188 	reseteval();
189 	resetinput();
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 
197 static void
198 cmdloop(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 (pendingsig)
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 == SKIPRETURN)
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 
250 static void
251 read_profile(const char *name)
252 {
253 	int fd;
254 	const char *expandedname;
255 
256 	expandedname = expandstr(name);
257 	if (expandedname == NULL)
258 		return;
259 	INTOFF;
260 	if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 0)
261 		setinputfd(fd, 1);
262 	INTON;
263 	if (fd < 0)
264 		return;
265 	cmdloop(0);
266 	popfile();
267 }
268 
269 
270 
271 /*
272  * Read a file containing shell functions.
273  */
274 
275 void
276 readcmdfile(const char *name)
277 {
278 	setinputfile(name, 1);
279 	cmdloop(0);
280 	popfile();
281 }
282 
283 
284 
285 /*
286  * Take commands from a file.  To be compatible we should do a path
287  * search for the file, which is necessary to find sub-commands.
288  */
289 
290 
291 static char *
292 find_dot_file(char *basename)
293 {
294 	char *fullname;
295 	const char *path = pathval();
296 	struct stat statb;
297 
298 	/* don't try this for absolute or relative paths */
299 	if( strchr(basename, '/'))
300 		return basename;
301 
302 	while ((fullname = padvance(&path, basename)) != NULL) {
303 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
304 			/*
305 			 * Don't bother freeing here, since it will
306 			 * be freed by the caller.
307 			 */
308 			return fullname;
309 		}
310 		stunalloc(fullname);
311 	}
312 	return basename;
313 }
314 
315 int
316 dotcmd(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 
340 int
341 exitcmd(int argc, char **argv)
342 {
343 	if (stoppedjobs())
344 		return 0;
345 	if (argc > 1)
346 		exitshell(number(argv[1]));
347 	else
348 		exitshell_savedstatus();
349 }
350