xref: /freebsd/bin/sh/main.c (revision 1670a1c2a47d10ecccd001970b859caf93cd3b6e)
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 			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");
162 state1:
163 		state = 2;
164 		if (privileged == 0)
165 			read_profile(".profile");
166 		else
167 			read_profile("/etc/suid_profile");
168 	}
169 state2:
170 	state = 3;
171 	if (!privileged && iflag) {
172 		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
173 			state = 3;
174 			read_profile(shinit);
175 		}
176 	}
177 state3:
178 	state = 4;
179 	if (minusc) {
180 		evalstring(minusc, sflag ? 0 : EV_EXIT);
181 	}
182 	if (sflag || minusc == NULL) {
183 state4:	/* 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 
197 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 (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 == SKIPFILE) {
236 			evalskip = 0;
237 			break;
238 		}
239 	}
240 	popstackmark(&smark);
241 }
242 
243 
244 
245 /*
246  * Read /etc/profile or .profile.  Return on error.
247  */
248 
249 STATIC void
250 read_profile(const char *name)
251 {
252 	int fd;
253 
254 	INTOFF;
255 	if ((fd = open(name, O_RDONLY)) >= 0)
256 		setinputfd(fd, 1);
257 	INTON;
258 	if (fd < 0)
259 		return;
260 	cmdloop(0);
261 	popfile();
262 }
263 
264 
265 
266 /*
267  * Read a file containing shell functions.
268  */
269 
270 void
271 readcmdfile(const char *name)
272 {
273 	int fd;
274 
275 	INTOFF;
276 	if ((fd = open(name, O_RDONLY)) >= 0)
277 		setinputfd(fd, 1);
278 	else
279 		error("Can't open %s: %s", name, strerror(errno));
280 	INTON;
281 	cmdloop(0);
282 	popfile();
283 }
284 
285 
286 
287 /*
288  * Take commands from a file.  To be compatible we should do a path
289  * search for the file, which is necessary to find sub-commands.
290  */
291 
292 
293 STATIC char *
294 find_dot_file(char *basename)
295 {
296 	static char localname[FILENAME_MAX+1];
297 	char *fullname;
298 	const char *path = pathval();
299 	struct stat statb;
300 
301 	/* don't try this for absolute or relative paths */
302 	if( strchr(basename, '/'))
303 		return basename;
304 
305 	while ((fullname = padvance(&path, basename)) != NULL) {
306 		strcpy(localname, fullname);
307 		stunalloc(fullname);
308 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode))
309 			return localname;
310 	}
311 	return basename;
312 }
313 
314 int
315 dotcmd(int argc, char **argv)
316 {
317 	char *filename, *fullname;
318 
319 	if (argc < 2)
320 		error("missing filename");
321 
322 	exitstatus = 0;
323 
324 	/*
325 	 * Because we have historically not supported any options,
326 	 * only treat "--" specially.
327 	 */
328 	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
329 
330 	fullname = find_dot_file(filename);
331 	setinputfile(fullname, 1);
332 	commandname = fullname;
333 	cmdloop(0);
334 	popfile();
335 	return exitstatus;
336 }
337 
338 
339 int
340 exitcmd(int argc, char **argv)
341 {
342 	if (stoppedjobs())
343 		return 0;
344 	if (argc > 1)
345 		exitstatus = number(argv[1]);
346 	else
347 		exitstatus = oexitstatus;
348 	exitshell(exitstatus);
349 	/*NOTREACHED*/
350 	return 0;
351 }
352