error.c revision 213811 
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#if 0
35static char sccsid[] = "@(#)error.c	8.2 (Berkeley) 5/4/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: head/bin/sh/error.c 213811 2010-10-13 22:18:03Z obrien $");
40
41/*
42 * Errors and exceptions.
43 */
44
45#include "shell.h"
46#include "main.h"
47#include "options.h"
48#include "output.h"
49#include "error.h"
50#include "nodes.h" /* show.h needs nodes.h */
51#include "show.h"
52#include "trap.h"
53#include <signal.h>
54#include <stdlib.h>
55#include <unistd.h>
56#include <errno.h>
57
58
59/*
60 * Code to handle exceptions in C.
61 */
62
63struct jmploc *handler;
64volatile sig_atomic_t exception;
65volatile sig_atomic_t suppressint;
66volatile sig_atomic_t intpending;
67char *commandname;
68
69
70static void exverror(int, const char *, va_list) __printf0like(2, 0) __dead2;
71
72/*
73 * Called to raise an exception.  Since C doesn't include exceptions, we
74 * just do a longjmp to the exception handler.  The type of exception is
75 * stored in the global variable "exception".
76 *
77 * Interrupts are disabled; they should be reenabled when the exception is
78 * caught.
79 */
80
81void
82exraise(int e)
83{
84	INTOFF;
85	if (handler == NULL)
86		abort();
87	exception = e;
88	longjmp(handler->loc, 1);
89}
90
91
92/*
93 * Called from trap.c when a SIGINT is received.  (If the user specifies
94 * that SIGINT is to be trapped or ignored using the trap builtin, then
95 * this routine is not called.)  Suppressint is nonzero when interrupts
96 * are held using the INTOFF macro.  If SIGINTs are not suppressed and
97 * the shell is not a root shell, then we want to be terminated if we
98 * get here, as if we were terminated directly by a SIGINT.  Arrange for
99 * this here.
100 */
101
102void
103onint(void)
104{
105	sigset_t sigs;
106
107	/*
108	 * The !in_dotrap here is safe.  The only way we can arrive here
109	 * with in_dotrap set is that a trap handler set SIGINT to SIG_DFL
110	 * and killed itself.
111	 */
112
113	if (suppressint && !in_dotrap) {
114		intpending++;
115		return;
116	}
117	intpending = 0;
118	sigemptyset(&sigs);
119	sigprocmask(SIG_SETMASK, &sigs, NULL);
120
121	/*
122	 * This doesn't seem to be needed, since main() emits a newline.
123	 */
124#if 0
125	if (tcgetpgrp(0) == getpid())
126		write(STDERR_FILENO, "\n", 1);
127#endif
128	if (rootshell && iflag)
129		exraise(EXINT);
130	else {
131		signal(SIGINT, SIG_DFL);
132		kill(getpid(), SIGINT);
133	}
134}
135
136
137/*
138 * Exverror is called to raise the error exception.  If the first argument
139 * is not NULL then error prints an error message using printf style
140 * formatting.  It then raises the error exception.
141 */
142static void
143exverror(int cond, const char *msg, va_list ap)
144{
145	/*
146	 * An interrupt trumps an error.  Certain places catch error
147	 * exceptions or transform them to a plain nonzero exit code
148	 * in child processes, and if an error exception can be handled,
149	 * an interrupt can be handled as well.
150	 *
151	 * exraise() will disable interrupts for the exception handler.
152	 */
153	FORCEINTON;
154
155#ifdef DEBUG
156	if (msg)
157		TRACE(("exverror(%d, \"%s\") pid=%d\n", cond, msg, getpid()));
158	else
159		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));
160#endif
161	if (msg) {
162		if (commandname)
163			outfmt(out2, "%s: ", commandname);
164		doformat(out2, msg, ap);
165		out2c('\n');
166	}
167	flushall();
168	exraise(cond);
169}
170
171
172void
173error(const char *msg, ...)
174{
175	va_list ap;
176	va_start(ap, msg);
177	exverror(EXERROR, msg, ap);
178	va_end(ap);
179}
180
181
182void
183exerror(int cond, const char *msg, ...)
184{
185	va_list ap;
186	va_start(ap, msg);
187	exverror(cond, msg, ap);
188	va_end(ap);
189}
190