xref: /freebsd/bin/sh/main.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Kenneth Almquist.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef lint
36 static char const copyright[] =
37 "@(#) Copyright (c) 1991, 1993\n\
38 	The Regents of the University of California.  All rights reserved.\n";
39 #endif /* not lint */
40 
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/28/95";
44 #endif
45 #endif /* not lint */
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 #include <stdio.h>
50 #include <signal.h>
51 #include <sys/stat.h>
52 #include <unistd.h>
53 #include <fcntl.h>
54 #include <locale.h>
55 #include <errno.h>
56 
57 #include "shell.h"
58 #include "main.h"
59 #include "mail.h"
60 #include "options.h"
61 #include "output.h"
62 #include "parser.h"
63 #include "nodes.h"
64 #include "expand.h"
65 #include "eval.h"
66 #include "jobs.h"
67 #include "input.h"
68 #include "trap.h"
69 #include "var.h"
70 #include "show.h"
71 #include "memalloc.h"
72 #include "error.h"
73 #include "mystring.h"
74 #include "exec.h"
75 #include "cd.h"
76 #include "redir.h"
77 #include "builtins.h"
78 
79 int rootpid;
80 int rootshell;
81 struct jmploc main_handler;
82 int localeisutf8, initial_localeisutf8;
83 
84 static void reset(void);
85 static void cmdloop(int);
86 static void read_profile(const char *);
87 static char *find_dot_file(char *);
88 
89 /*
90  * Main routine.  We initialize things, parse the arguments, execute
91  * profiles if we're a login shell, and then call cmdloop to execute
92  * commands.  The setjmp call sets up the location to jump to when an
93  * exception occurs.  When an exception occurs the variable "state"
94  * is used to figure out how far we had gotten.
95  */
96 
97 int
98 main(int argc, char *argv[])
99 {
100 	struct stackmark smark, smark2;
101 	volatile int state;
102 	char *shinit;
103 
104 	(void) setlocale(LC_ALL, "");
105 	initcharset();
106 	state = 0;
107 	if (setjmp(main_handler.loc)) {
108 		switch (exception) {
109 		case EXEXEC:
110 			exitstatus = exerrno;
111 			break;
112 
113 		case EXERROR:
114 			exitstatus = 2;
115 			break;
116 
117 		default:
118 			break;
119 		}
120 
121 		if (state == 0 || iflag == 0 || ! rootshell ||
122 		    exception == EXEXIT)
123 			exitshell(exitstatus);
124 		reset();
125 		if (exception == EXINT)
126 			out2fmt_flush("\n");
127 		popstackmark(&smark);
128 		FORCEINTON;				/* enable interrupts */
129 		if (state == 1)
130 			goto state1;
131 		else if (state == 2)
132 			goto state2;
133 		else if (state == 3)
134 			goto state3;
135 		else
136 			goto state4;
137 	}
138 	handler = &main_handler;
139 #ifdef DEBUG
140 	opentrace();
141 	trputs("Shell args:  ");  trargs(argv);
142 #endif
143 	rootpid = getpid();
144 	rootshell = 1;
145 	INTOFF;
146 	initvar();
147 	setstackmark(&smark);
148 	setstackmark(&smark2);
149 	procargs(argc, argv);
150 	pwd_init(iflag);
151 	INTON;
152 	if (iflag)
153 		chkmail(1);
154 	if (argv[0] && argv[0][0] == '-') {
155 		state = 1;
156 		read_profile("/etc/profile");
157 state1:
158 		state = 2;
159 		if (privileged == 0)
160 			read_profile("${HOME-}/.profile");
161 		else
162 			read_profile("/etc/suid_profile");
163 	}
164 state2:
165 	state = 3;
166 	if (!privileged && iflag) {
167 		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
168 			state = 3;
169 			read_profile(shinit);
170 		}
171 	}
172 state3:
173 	state = 4;
174 	popstackmark(&smark2);
175 	if (minusc) {
176 		evalstring(minusc, sflag ? 0 : EV_EXIT);
177 	}
178 state4:
179 	if (sflag || minusc == NULL) {
180 		cmdloop(1);
181 	}
182 	exitshell(exitstatus);
183 	/*NOTREACHED*/
184 	return 0;
185 }
186 
187 static void
188 reset(void)
189 {
190 	reseteval();
191 	resetinput();
192 }
193 
194 /*
195  * Read and execute commands.  "Top" is nonzero for the top level command
196  * loop; it turns on prompting if the shell is interactive.
197  */
198 
199 static void
200 cmdloop(int top)
201 {
202 	union node *n;
203 	struct stackmark smark;
204 	int inter;
205 	int numeof = 0;
206 
207 	TRACE(("cmdloop(%d) called\n", top));
208 	setstackmark(&smark);
209 	for (;;) {
210 		if (pendingsig)
211 			dotrap();
212 		inter = 0;
213 		if (iflag && top) {
214 			inter++;
215 			showjobs(1, SHOWJOBS_DEFAULT);
216 			chkmail(0);
217 			flushout(&output);
218 		}
219 		n = parsecmd(inter);
220 		/* showtree(n); DEBUG */
221 		if (n == NEOF) {
222 			if (!top || numeof >= 50)
223 				break;
224 			if (!stoppedjobs()) {
225 				if (!Iflag)
226 					break;
227 				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
228 			}
229 			numeof++;
230 		} else if (n != NULL && nflag == 0) {
231 			job_warning = (job_warning == 2) ? 1 : 0;
232 			numeof = 0;
233 			evaltree(n, 0);
234 		}
235 		popstackmark(&smark);
236 		setstackmark(&smark);
237 		if (evalskip != 0) {
238 			if (evalskip == SKIPRETURN)
239 				evalskip = 0;
240 			break;
241 		}
242 	}
243 	popstackmark(&smark);
244 }
245 
246 
247 
248 /*
249  * Read /etc/profile or .profile.  Return on error.
250  */
251 
252 static void
253 read_profile(const char *name)
254 {
255 	int fd;
256 	const char *expandedname;
257 
258 	expandedname = expandstr(name);
259 	if (expandedname == NULL)
260 		return;
261 	INTOFF;
262 	if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 0)
263 		setinputfd(fd, 1);
264 	INTON;
265 	if (fd < 0)
266 		return;
267 	cmdloop(0);
268 	popfile();
269 }
270 
271 
272 
273 /*
274  * Read a file containing shell functions.
275  */
276 
277 void
278 readcmdfile(const char *name)
279 {
280 	setinputfile(name, 1);
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 	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 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
306 			/*
307 			 * Don't bother freeing here, since it will
308 			 * be freed by the caller.
309 			 */
310 			return fullname;
311 		}
312 		stunalloc(fullname);
313 	}
314 	return basename;
315 }
316 
317 int
318 dotcmd(int argc, char **argv)
319 {
320 	char *filename, *fullname;
321 
322 	if (argc < 2)
323 		error("missing filename");
324 
325 	exitstatus = 0;
326 
327 	/*
328 	 * Because we have historically not supported any options,
329 	 * only treat "--" specially.
330 	 */
331 	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
332 
333 	fullname = find_dot_file(filename);
334 	setinputfile(fullname, 1);
335 	commandname = fullname;
336 	cmdloop(0);
337 	popfile();
338 	return exitstatus;
339 }
340 
341 
342 int
343 exitcmd(int argc, char **argv)
344 {
345 	if (stoppedjobs())
346 		return 0;
347 	if (argc > 1)
348 		exitshell(number(argv[1]));
349 	else
350 		exitshell_savedstatus();
351 }
352