xref: /freebsd/bin/sh/main.c (revision a0409676120c1e558d0ade943019934e0f15118d)
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 		if (state == 0 || iflag == 0 || ! rootshell ||
109 		    exception == EXEXIT)
110 			exitshell(exitstatus);
111 		reset();
112 		if (exception == EXINT)
113 			out2fmt_flush("\n");
114 		popstackmark(&smark);
115 		FORCEINTON;				/* enable interrupts */
116 		if (state == 1)
117 			goto state1;
118 		else if (state == 2)
119 			goto state2;
120 		else if (state == 3)
121 			goto state3;
122 		else
123 			goto state4;
124 	}
125 	handler = &main_handler;
126 #ifdef DEBUG
127 	opentrace();
128 	trputs("Shell args:  ");  trargs(argv);
129 #endif
130 	rootpid = getpid();
131 	rootshell = 1;
132 	INTOFF;
133 	initvar();
134 	setstackmark(&smark);
135 	setstackmark(&smark2);
136 	procargs(argc, argv);
137 	trap_init();
138 	pwd_init(iflag);
139 	INTON;
140 	if (iflag)
141 		chkmail(1);
142 	if (argv[0] && argv[0][0] == '-') {
143 		state = 1;
144 		read_profile("/etc/profile");
145 state1:
146 		state = 2;
147 		if (privileged == 0)
148 			read_profile("${HOME-}/.profile");
149 		else
150 			read_profile("/etc/suid_profile");
151 	}
152 state2:
153 	state = 3;
154 	if (!privileged && iflag) {
155 		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
156 			state = 3;
157 			read_profile(shinit);
158 		}
159 	}
160 state3:
161 	state = 4;
162 	popstackmark(&smark2);
163 	if (minusc) {
164 		evalstring(minusc, sflag ? 0 : EV_EXIT);
165 	}
166 state4:
167 	if (sflag || minusc == NULL) {
168 		cmdloop(1);
169 	}
170 	exitshell(exitstatus);
171 	/*NOTREACHED*/
172 	return 0;
173 }
174 
175 static void
176 reset(void)
177 {
178 	reseteval();
179 	resetinput();
180 }
181 
182 /*
183  * Read and execute commands.  "Top" is nonzero for the top level command
184  * loop; it turns on prompting if the shell is interactive.
185  */
186 
187 static void
188 cmdloop(int top)
189 {
190 	union node *n;
191 	struct stackmark smark;
192 	int inter;
193 	int numeof = 0;
194 
195 	TRACE(("cmdloop(%d) called\n", top));
196 	setstackmark(&smark);
197 	for (;;) {
198 		if (pendingsig)
199 			dotrap();
200 		inter = 0;
201 		if (iflag && top) {
202 			inter++;
203 			showjobs(1, SHOWJOBS_DEFAULT);
204 			chkmail(0);
205 			flushout(&output);
206 		}
207 		n = parsecmd(inter);
208 		/* showtree(n); DEBUG */
209 		if (n == NEOF) {
210 			if (!top || numeof >= 50)
211 				break;
212 			if (!stoppedjobs()) {
213 				if (!Iflag)
214 					break;
215 				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
216 			}
217 			numeof++;
218 		} else if (n != NULL && nflag == 0) {
219 			job_warning = (job_warning == 2) ? 1 : 0;
220 			numeof = 0;
221 			evaltree(n, 0);
222 		}
223 		popstackmark(&smark);
224 		setstackmark(&smark);
225 		if (evalskip != 0) {
226 			if (evalskip == SKIPRETURN)
227 				evalskip = 0;
228 			break;
229 		}
230 	}
231 	popstackmark(&smark);
232 	if (top && iflag) {
233 		out2c('\n');
234 		flushout(out2);
235 	}
236 }
237 
238 
239 
240 /*
241  * Read /etc/profile or .profile.  Return on error.
242  */
243 
244 static void
245 read_profile(const char *name)
246 {
247 	int fd;
248 	const char *expandedname;
249 
250 	expandedname = expandstr(name);
251 	if (expandedname == NULL)
252 		return;
253 	INTOFF;
254 	if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 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 	setinputfile(name, 1);
273 	cmdloop(0);
274 	popfile();
275 }
276 
277 
278 
279 /*
280  * Take commands from a file.  To be compatible we should do a path
281  * search for the file, which is necessary to find sub-commands.
282  */
283 
284 
285 static char *
286 find_dot_file(char *basename)
287 {
288 	char *fullname;
289 	const char *opt;
290 	const char *path = pathval();
291 	struct stat statb;
292 
293 	/* don't try this for absolute or relative paths */
294 	if( strchr(basename, '/'))
295 		return basename;
296 
297 	while ((fullname = padvance(&path, &opt, basename)) != NULL) {
298 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
299 			/*
300 			 * Don't bother freeing here, since it will
301 			 * be freed by the caller.
302 			 */
303 			return fullname;
304 		}
305 		stunalloc(fullname);
306 	}
307 	return basename;
308 }
309 
310 int
311 dotcmd(int argc, char **argv)
312 {
313 	char *filename, *fullname;
314 
315 	if (argc < 2)
316 		error("missing filename");
317 
318 	exitstatus = 0;
319 
320 	/*
321 	 * Because we have historically not supported any options,
322 	 * only treat "--" specially.
323 	 */
324 	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
325 
326 	fullname = find_dot_file(filename);
327 	setinputfile(fullname, 1);
328 	commandname = fullname;
329 	cmdloop(0);
330 	popfile();
331 	return exitstatus;
332 }
333 
334 
335 int
336 exitcmd(int argc, char **argv)
337 {
338 	if (stoppedjobs())
339 		return 0;
340 	if (argc > 1)
341 		exitshell(number(argv[1]));
342 	else
343 		exitshell_savedstatus();
344 }
345