error.c

操作系统源代码

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)error.c	5.1 (Berkeley) 3/7/91";
#endif /* not lint */

/*
 * Errors and exceptions.
 */

#include "shell.h"
#include "main.h"
#include "options.h"
#include "output.h"
#include "error.h"
#include <sys/types.h>
#include <signal.h>
#ifdef __STDC__
#include "stdarg.h"
#else
#include <varargs.h>	
#endif
#include <errno.h>


/*
 * Code to handle exceptions in C.
 */

struct jmploc *handler;
int exception;
volatile int suppressint;
volatile int intpending;
char *commandname;


/*
 * Called to raise an exception.  Since C doesn't include exceptions, we
 * just do a longjmp to the exception handler.  The type of exception is
 * stored in the global variable "exception".
 */

void
exraise(e) {
	if (handler == NULL)
		abort();
	exception = e;
	longjmp(handler->loc, 1);
}


/*
 * Called from trap.c when a SIGINT is received.  (If the user specifies
 * that SIGINT is to be trapped or ignored using the trap builtin, then
 * this routine is not called.)  Suppressint is nonzero when interrupts
 * are held using the INTOFF macro.  The call to _exit is necessary because
 * there is a short period after a fork before the signal handlers are
 * set to the appropriate value for the child.  (The test for iflag is
 * just defensive programming.)
 */

void
onint() {
	if (suppressint) {
		intpending++;
		return;
	}
	intpending = 0;
#ifdef BSD
	sigsetmask(0);
#endif
	if (rootshell && iflag)
		exraise(EXINT);
	else
		_exit(128 + SIGINT);
}



void
error2(a, b)
	char *a, *b;
	{
	error("%s: %s", a, b);
}


/*
 * Error is called to raise the error exception.  If the first argument
 * is not NULL then error prints an error message using printf style
 * formatting.  It then raises the error exception.
 */

#ifdef __STDC__
void
error(char *msg, ...) {
#else
void
error(va_alist)
	va_dcl
	{
	char *msg;
#endif
	va_list ap;

	CLEAR_PENDING_INT;
	INTOFF;
#ifdef __STDC__
	va_start(ap, msg);
#else
	va_start(ap);
	msg = va_arg(ap, char *);
#endif
#if DEBUG
	if (msg)
		TRACE(("error(\"%s\") pid=%d\n", msg, getpid()));
	else
		TRACE(("error(NULL) pid=%d\n", getpid()));
#endif
	if (msg) {
		if (commandname)
			outfmt(&errout, "%s: ", commandname);
		doformat(&errout, msg, ap);
		out2c('\n');
	}
	va_end(ap);
	flushall();
	exraise(EXERROR);
}



/*
 * Table of error messages.
 */

struct errname {
	short errcode;		/* error number */
	short action;		/* operation which encountered the error */
	char *msg;		/* text describing the error */
};


#define ALL (E_OPEN|E_CREAT|E_EXEC)

STATIC const struct errname errormsg[] = {
	EINTR, ALL,	"interrupted",
	EACCES, ALL,	"permission denied",
	EIO, ALL,		"I/O error",
	ENOENT, E_OPEN,	"no such file",
	ENOENT, E_CREAT,	"directory nonexistent",
	ENOENT, E_EXEC,	"not found",
	ENOTDIR, E_OPEN,	"no such file",
	ENOTDIR, E_CREAT,	"directory nonexistent",
	ENOTDIR, E_EXEC,	"not found",
#if __minix_vmd
	ENOEXEC, ALL,	"not an executable",
#endif
	EISDIR, ALL,	"is a directory",
/*    EMFILE, ALL,	"too many open files", */
	ENFILE, ALL,	"file table overflow",
	ENOSPC, ALL,	"file system full",
#ifdef EDQUOT
	EDQUOT, ALL,	"disk quota exceeded",
#endif
#ifdef ENOSR
	ENOSR, ALL,	"no streams resources",
#endif
	ENXIO, ALL,	"no such device or address",
	EROFS, ALL,	"read-only file system",
	ETXTBSY, ALL,	"text busy",
#ifdef SYSV
	EAGAIN, E_EXEC,	"not enough memory",
#endif
	ENOMEM, ALL,	"not enough memory",
#ifdef ENOLINK
	ENOLINK, ALL,	"remote access failed",
#endif
#ifdef EMULTIHOP
	EMULTIHOP, ALL,	"remote access failed",
#endif
#ifdef ECOMM
	ECOMM, ALL,	"remote access failed",
#endif
#ifdef ESTALE
	ESTALE, ALL,	"remote access failed",
#endif
#ifdef ETIMEDOUT
	ETIMEDOUT, ALL,	"remote access failed",
#endif
#ifdef ELOOP
	ELOOP, ALL,	"symbolic link loop",
#endif
	E2BIG, E_EXEC,	"argument list too long",
#ifdef ELIBACC
	ELIBACC, E_EXEC,	"shared library missing",
#endif
	0, 0,		NULL
};


/*
 * Return a string describing an error.  The returned string may be a
 * pointer to a static buffer that will be overwritten on the next call.
 * Action describes the operation that got the error.
 */

char *
errmsg(e, action) {
	const struct errname *ep;
	static char buf[12];

	for (ep = errormsg ; ep->errcode ; ep++) {
		if (ep->errcode == e && (ep->action & action) != 0)
			return ep->msg;
	}
	fmtstr(buf, sizeof buf, "error %d", e);
	return buf;
}