xref: /csrg-svn/bin/sh/main.c (revision 68926)
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  * %sccs.include.redist.c%
9  */
10 
11 #ifndef lint
12 static char copyright[] =
13 "@(#) Copyright (c) 1991, 1993\n\
14 	The Regents of the University of California.  All rights reserved.\n";
15 #endif /* not lint */
16 
17 #ifndef lint
18 static char sccsid[] = "@(#)main.c	8.2 (Berkeley) 04/27/95";
19 #endif /* not lint */
20 
21 #include <sys/stat.h>
22 #include <stdio.h>
23 #include <signal.h>
24 #include <fcntl.h>
25 #include "shell.h"
26 #include "main.h"
27 #include "mail.h"
28 #include "options.h"
29 #include "output.h"
30 #include "parser.h"
31 #include "nodes.h"
32 #include "eval.h"
33 #include "jobs.h"
34 #include "input.h"
35 #include "trap.h"
36 #include "var.h"
37 #include "memalloc.h"
38 #include "error.h"
39 #include "init.h"
40 #include "mystring.h"
41 #include "exec.h"
42 
43 #define PROFILE 0
44 
45 int rootpid;
46 int rootshell;
47 STATIC union node *curcmd;
48 STATIC union node *prevcmd;
49 extern int errno;
50 #if PROFILE
51 short profile_buf[16384];
52 extern int etext();
53 #endif
54 
55 #ifdef __STDC__
56 STATIC void read_profile(char *);
57 char *getenv(char *);
58 #else
59 STATIC void read_profile();
60 char *getenv();
61 #endif
62 
63 
64 /*
65  * Main routine.  We initialize things, parse the arguments, execute
66  * profiles if we're a login shell, and then call cmdloop to execute
67  * commands.  The setjmp call sets up the location to jump to when an
68  * exception occurs.  When an exception occurs the variable "state"
69  * is used to figure out how far we had gotten.
70  */
71 
72 main(argc, argv)  char **argv; {
73 	struct jmploc jmploc;
74 	struct stackmark smark;
75 	volatile int state;
76 	char *shinit;
77 
78 #if PROFILE
79 	monitor(4, etext, profile_buf, sizeof profile_buf, 50);
80 #endif
81 	state = 0;
82 	if (setjmp(jmploc.loc)) {
83 		/*
84 		 * When a shell procedure is executed, we raise the
85 		 * exception EXSHELLPROC to clean up before executing
86 		 * the shell procedure.
87 		 */
88 		if (exception == EXSHELLPROC) {
89 			rootpid = getpid();
90 			rootshell = 1;
91 			minusc = NULL;
92 			state = 3;
93 		} else if (state == 0 || iflag == 0 || ! rootshell)
94 			exitshell(2);
95 		reset();
96 		if (exception == EXINT
97 #if ATTY
98 		 && (! attyset() || equal(termval(), "emacs"))
99 #endif
100 		 ) {
101 			out2c('\n');
102 			flushout(&errout);
103 		}
104 		popstackmark(&smark);
105 		FORCEINTON;				/* enable interrupts */
106 		if (state == 1)
107 			goto state1;
108 		else if (state == 2)
109 			goto state2;
110 		else if (state == 3)
111 			goto state3;
112 		else
113 			goto state4;
114 	}
115 	handler = &jmploc;
116 #ifdef DEBUG
117 	opentrace();
118 	trputs("Shell args:  ");  trargs(argv);
119 #endif
120 	rootpid = getpid();
121 	rootshell = 1;
122 	init();
123 	setstackmark(&smark);
124 	procargs(argc, argv);
125 	if (argv[0] && argv[0][0] == '-') {
126 		state = 1;
127 		read_profile("/etc/profile");
128 state1:
129 		state = 2;
130 		read_profile(".profile");
131 	}
132 state2:
133 	state = 3;
134 	if ((shinit = lookupvar("ENV")) != NULL &&
135 	     *shinit != '\0') {
136 		state = 3;
137 		read_profile(shinit);
138 	}
139 state3:
140 	state = 4;
141 	if (minusc) {
142 		evalstring(minusc);
143 	}
144 	if (sflag || minusc == NULL) {
145 state4:	/* XXX ??? - why isn't this before the "if" statement */
146 		cmdloop(1);
147 	}
148 #if PROFILE
149 	monitor(0);
150 #endif
151 	exitshell(exitstatus);
152 }
153 
154 
155 /*
156  * Read and execute commands.  "Top" is nonzero for the top level command
157  * loop; it turns on prompting if the shell is interactive.
158  */
159 
160 void
161 cmdloop(top) {
162 	union node *n;
163 	struct stackmark smark;
164 	int inter;
165 	int numeof = 0;
166 
167 	TRACE(("cmdloop(%d) called\n", top));
168 	setstackmark(&smark);
169 	for (;;) {
170 		if (pendingsigs)
171 			dotrap();
172 		inter = 0;
173 		if (iflag && top) {
174 			inter++;
175 			showjobs(1);
176 			chkmail(0);
177 			flushout(&output);
178 		}
179 		n = parsecmd(inter);
180 		/* showtree(n); DEBUG */
181 		if (n == NEOF) {
182 			if (!top || numeof >= 50)
183 				break;
184 			if (!stoppedjobs()) {
185 				if (!Iflag)
186 					break;
187 				out2str("\nUse \"exit\" to leave shell.\n");
188 			}
189 			numeof++;
190 		} else if (n != NULL && nflag == 0) {
191 			job_warning = (job_warning == 2) ? 1 : 0;
192 			numeof = 0;
193 			evaltree(n, 0);
194 		}
195 		popstackmark(&smark);
196 	}
197 	popstackmark(&smark);		/* unnecessary */
198 }
199 
200 
201 
202 /*
203  * Read /etc/profile or .profile.  Return on error.
204  */
205 
206 STATIC void
207 read_profile(name)
208 	char *name;
209 	{
210 	int fd;
211 
212 	INTOFF;
213 	if ((fd = open(name, O_RDONLY)) >= 0)
214 		setinputfd(fd, 1);
215 	INTON;
216 	if (fd < 0)
217 		return;
218 	cmdloop(0);
219 	popfile();
220 }
221 
222 
223 
224 /*
225  * Read a file containing shell functions.
226  */
227 
228 void
229 readcmdfile(name)
230 	char *name;
231 	{
232 	int fd;
233 
234 	INTOFF;
235 	if ((fd = open(name, O_RDONLY)) >= 0)
236 		setinputfd(fd, 1);
237 	else
238 		error("Can't open %s", name);
239 	INTON;
240 	cmdloop(0);
241 	popfile();
242 }
243 
244 
245 
246 /*
247  * Take commands from a file.  To be compatable we should do a path
248  * search for the file, which is necessary to find sub-commands.
249  */
250 
251 
252 static char *
253 find_dot_file(basename) char *basename; {
254 	static char localname[FILENAME_MAX+1];
255 	char *fullname;
256 	char *path = pathval();
257 	struct stat statb;
258 
259 	/* don't try this for absolute or relative paths */
260 	if( strchr(basename, '/'))
261 		return basename;
262 
263 	while ((fullname = padvance(&path, basename)) != NULL) {
264 		strcpy(localname, fullname);
265 		stunalloc(fullname);
266 		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode))
267 			return localname;
268 	}
269 	return basename;
270 }
271 
272 dotcmd(argc, argv)  char **argv; {
273 	exitstatus = 0;
274 	if (argc >= 2) {		/* That's what SVR2 does */
275 		char *fullname = find_dot_file(argv[1]);
276 		setinputfile(fullname, 1);
277 		commandname = fullname;
278 		cmdloop(0);
279 		popfile();
280 	}
281 	return exitstatus;
282 }
283 
284 
285 exitcmd(argc, argv)  char **argv; {
286 	if (stoppedjobs())
287 		return;
288 	if (argc > 1)
289 		exitstatus = number(argv[1]);
290 	exitshell(exitstatus);
291 }
292 
293 
294 #ifdef notdef
295 /*
296  * Should never be called.
297  */
298 
299 void
300 exit(exitstatus) {
301 	_exit(exitstatus);
302 }
303 #endif
304