xref: /dragonfly/bin/sh/main.c (revision 3e3895bf)
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 #if 0
37 static char sccsid[] = "@(#)main.c	8.6 (Berkeley) 5/28/95";
38 #endif
39 #endif /* not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: head/bin/sh/main.c 364919 2020-08-28 15:35:45Z jilles $");
42 
43 #include <stdio.h>
44 #include <signal.h>
45 #include <sys/stat.h>
46 #include <unistd.h>
47 #include <fcntl.h>
48 #include <locale.h>
49 #include <errno.h>
50 
51 #include "shell.h"
52 #include "main.h"
53 #include "mail.h"
54 #include "options.h"
55 #include "output.h"
56 #include "parser.h"
57 #include "nodes.h"
58 #include "expand.h"
59 #include "eval.h"
60 #include "jobs.h"
61 #include "input.h"
62 #include "trap.h"
63 #include "var.h"
64 #include "show.h"
65 #include "memalloc.h"
66 #include "error.h"
67 #include "mystring.h"
68 #include "exec.h"
69 #include "cd.h"
70 #include "redir.h"
71 #include "builtins.h"
72 
73 int rootpid;
74 int rootshell;
75 struct jmploc main_handler;
76 int localeisutf8, initial_localeisutf8;
77 
78 static void reset(void);
79 static void cmdloop(int);
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
main(int argc,char * argv[])92 main(int argc, char *argv[])
93 {
94 	struct stackmark smark, smark2;
95 	volatile int state;
96 	char *shinit;
97 
98 	(void) setlocale(LC_ALL, "");
99 	initcharset();
100 	state = 0;
101 	if (setjmp(main_handler.loc)) {
102 		if (state == 0 || iflag == 0 || ! rootshell ||
103 		    exception == EXEXIT)
104 			exitshell(exitstatus);
105 		reset();
106 		if (exception == EXINT)
107 			out2fmt_flush("\n");
108 		popstackmark(&smark);
109 		FORCEINTON;				/* enable interrupts */
110 		if (state == 1)
111 			goto state1;
112 		else if (state == 2)
113 			goto state2;
114 		else if (state == 3)
115 			goto state3;
116 		else
117 			goto state4;
118 	}
119 	handler = &main_handler;
120 #ifdef DEBUG
121 	opentrace();
122 	trputs("Shell args:  ");  trargs(argv);
123 #endif
124 	rootpid = getpid();
125 	rootshell = 1;
126 	INTOFF;
127 	initvar();
128 	setstackmark(&smark);
129 	setstackmark(&smark2);
130 	procargs(argc, argv);
131 	trap_init();
132 	pwd_init(iflag);
133 	INTON;
134 	if (iflag)
135 		chkmail(1);
136 	if (argv[0] && argv[0][0] == '-') {
137 		state = 1;
138 		read_profile("/etc/profile");
139 state1:
140 		state = 2;
141 		if (privileged == 0)
142 			read_profile("${HOME-}/.profile");
143 		else
144 			read_profile("/etc/suid_profile");
145 	}
146 state2:
147 	state = 3;
148 	if (!privileged && iflag) {
149 		if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
150 			state = 3;
151 			read_profile(shinit);
152 		}
153 	}
154 state3:
155 	state = 4;
156 	popstackmark(&smark2);
157 	if (minusc) {
158 		evalstring(minusc, sflag ? 0 : EV_EXIT);
159 	}
160 state4:
161 	if (sflag || minusc == NULL) {
162 		cmdloop(1);
163 	}
164 	exitshell(exitstatus);
165 	/*NOTREACHED*/
166 	return 0;
167 }
168 
169 static void
reset(void)170 reset(void)
171 {
172 	reseteval();
173 	resetinput();
174 }
175 
176 /*
177  * Read and execute commands.  "Top" is nonzero for the top level command
178  * loop; it turns on prompting if the shell is interactive.
179  */
180 
181 static void
cmdloop(int top)182 cmdloop(int top)
183 {
184 	union node *n;
185 	struct stackmark smark;
186 	int inter;
187 	int numeof = 0;
188 
189 	TRACE(("cmdloop(%d) called\n", top));
190 	setstackmark(&smark);
191 	for (;;) {
192 		if (pendingsig)
193 			dotrap();
194 		inter = 0;
195 		if (iflag && top) {
196 			inter++;
197 			showjobs(1, SHOWJOBS_DEFAULT);
198 			chkmail(0);
199 			flushout(&output);
200 		}
201 		n = parsecmd(inter);
202 		/* showtree(n); DEBUG */
203 		if (n == NEOF) {
204 			if (!top || numeof >= 50)
205 				break;
206 			if (!stoppedjobs()) {
207 				if (!Iflag)
208 					break;
209 				out2fmt_flush("\nUse \"exit\" to leave shell.\n");
210 			}
211 			numeof++;
212 		} else if (n != NULL && nflag == 0) {
213 			job_warning = (job_warning == 2) ? 1 : 0;
214 			numeof = 0;
215 			evaltree(n, 0);
216 		}
217 		popstackmark(&smark);
218 		setstackmark(&smark);
219 		if (evalskip != 0) {
220 			if (evalskip == SKIPRETURN)
221 				evalskip = 0;
222 			break;
223 		}
224 	}
225 	popstackmark(&smark);
226 	if (top && iflag) {
227 		out2c('\n');
228 		flushout(out2);
229 	}
230 }
231 
232 
233 
234 /*
235  * Read /etc/profile or .profile.  Return on error.
236  */
237 
238 static void
read_profile(const char * name)239 read_profile(const char *name)
240 {
241 	int fd;
242 	const char *expandedname;
243 
244 	expandedname = expandstr(name);
245 	if (expandedname == NULL)
246 		return;
247 	INTOFF;
248 	if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC_MAYBE)) >= 0)
249 		setinputfd(fd, 1);
250 	INTON;
251 	if (fd < 0)
252 		return;
253 	cmdloop(0);
254 	popfile();
255 }
256 
257 
258 
259 /*
260  * Read a file containing shell functions.
261  */
262 
263 void
readcmdfile(const char * name)264 readcmdfile(const char *name)
265 {
266 	setinputfile(name, 1);
267 	cmdloop(0);
268 	popfile();
269 }
270 
271 
272 
273 /*
274  * Take commands from a file.  To be compatible we should do a path
275  * search for the file, which is necessary to find sub-commands.
276  */
277 
278 
279 static char *
find_dot_file(char * basename)280 find_dot_file(char *basename)
281 {
282 	char *fullname;
283 	const char *opt;
284 	const char *path = pathval();
285 	struct stat statb;
286 
287 	/* don't try this for absolute or relative paths */
288 	if( strchr(basename, '/'))
289 		return basename;
290 
291 	while ((fullname = padvance(&path, &opt, basename)) != NULL) {
292 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
293 			/*
294 			 * Don't bother freeing here, since it will
295 			 * be freed by the caller.
296 			 */
297 			return fullname;
298 		}
299 		stunalloc(fullname);
300 	}
301 	return basename;
302 }
303 
304 int
dotcmd(int argc,char ** argv)305 dotcmd(int argc, char **argv)
306 {
307 	char *filename, *fullname;
308 
309 	if (argc < 2)
310 		error("missing filename");
311 
312 	exitstatus = 0;
313 
314 	/*
315 	 * Because we have historically not supported any options,
316 	 * only treat "--" specially.
317 	 */
318 	filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
319 
320 	fullname = find_dot_file(filename);
321 	setinputfile(fullname, 1);
322 	commandname = fullname;
323 	cmdloop(0);
324 	popfile();
325 	return exitstatus;
326 }
327 
328 
329 int
exitcmd(int argc,char ** argv)330 exitcmd(int argc, char **argv)
331 {
332 	if (stoppedjobs())
333 		return 0;
334 	if (argc > 1)
335 		exitshell(number(argv[1]));
336 	else
337 		exitshell_savedstatus();
338 }
339