ObjFW  Artifact [23bfa51fc4]

Artifact 23bfa51fc4ee6088cf015c517673c16b3ce5650eb392f156de9d83c65fc4fc59:

• File src/exceptions/OFException.m — part of check-in [62e2de30b9] at 2015-02-16 08:39:17 on branch trunk — Explicitly pass errno to exceptions

  The old behaviour where the exception would access errno directly on
  creation of the exception was very fragile. The two main problems with
  it were that sometimes it would pick up an errno even though none had
  been set and in other cases that when the exception was created errno
  had already been overridden.

  This also greatly increases errno handling on Win32, especially in
  conjunction with sockets. It can still be improved further, though. (user: js, size: 6477) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#include <errno.h>
#include <stdlib.h>

#ifdef HAVE_DLFCN_H
# include <dlfcn.h>
#endif

#import "OFException.h"
#import "OFString.h"
#import "OFArray.h"
#import "OFSystemInfo.h"

#import "OFInitializationFailedException.h"
#import "OFLockFailedException.h"
#import "OFUnlockFailedException.h"

#if !defined(HAVE_STRERROR_R) && defined(OF_HAVE_THREADS)
# import "threading.h"
#endif

#if defined(_WIN32) && defined(OF_HAVE_SOCKETS)
# include <winerror.h>
#endif

/*
 * Define HAVE_DWARF_EXCEPTIONS if OBJC_ZEROCOST_EXCEPTIONS is defined, but
 * don't do so on iOS, as it is defined there even if SjLj exceptions are used.
 */
#ifndef HAVE_DWARF_EXCEPTIONS
# if defined(OBJC_ZEROCOST_EXCEPTIONS) && !defined(OF_IOS)
#  define HAVE_DWARF_EXCEPTIONS
# endif
#endif

/*
 * Define HAVE_DWARF_EXCEPTIONS if HAVE_SEH_EXCEPTIONS is defined, as SEH
 * exceptions are implemented as a wrapper around DWARF exceptions.
 */
#ifdef HAVE_SEH_EXCEPTIONS
# define HAVE_DWARF_EXCEPTIONS
#endif

#ifdef HAVE_DWARF_EXCEPTIONS
struct _Unwind_Context;
typedef enum {
	_URC_OK		  = 0,
	_URC_END_OF_STACK = 5
}_Unwind_Reason_Code;

struct backtrace_ctx {
	void **backtrace;
	uint_fast8_t i;
};

extern _Unwind_Reason_Code _Unwind_Backtrace(
    _Unwind_Reason_Code(*)(struct _Unwind_Context*, void*), void*);
# if defined(__arm__) || defined(__ARM__)
extern int _Unwind_VRS_Get(struct _Unwind_Context*, int, uint32_t, int, void*);
# else
extern uintptr_t _Unwind_GetIP(struct _Unwind_Context*);
# endif

#if !defined(HAVE_STRERROR_R) && defined(OF_HAVE_THREADS)
static of_mutex_t mutex;

static void __attribute__((__constructor__))
init(void)
{
	if (!of_mutex_new(&mutex))
		@throw [OFInitializationFailedException exception];
}
#endif

OFString*
of_strerror(int errNo)
{
	OFString *ret;
#ifdef HAVE_STRERROR_R
	char buffer[256];
#endif

#ifdef _WIN32
	/*
	 * These were translated from WSAE* errors to errno and thus Win32's
	 * strerror_r() does not know about them.
	 *
	 * FIXME: These could have better descriptions!
	 */
	switch (errNo) {
	case EADDRINUSE:
		return @"EADDRINUSE";
	case EADDRNOTAVAIL:
		return @"EADDRNOTAVAIL";
	case EAFNOSUPPORT:
		return @"EAFNOSUPPORT";
	case EALREADY:
		return @"EALREADY";
	case ECONNABORTED:
		return @"ECONNABORTED";
	case ECONNREFUSED:
		return @"ECONNREFUSED";
	case ECONNRESET:
		return @"ECONNRESET";
	case EDESTADDRREQ:
		return @"EDESTADDRREQ";
	case EDQUOT:
		return @"EDQUOT";
	case EHOSTDOWN:
		return @"EHOSTDOWN";
	case EHOSTUNREACH:
		return @"EHOSTUNREACH";
	case EINPROGRESS:
		return @"EINPROGRESS";
	case EISCONN:
		return @"EISCONN";
	case ELOOP:
		return @"ELOOP";
	case EMSGSIZE:
		return @"EMSGSIZE";
	case ENETDOWN:
		return @"ENETDOWN";
	case ENETRESET:
		return @"ENETRESET";
	case ENETUNREACH:
		return @"ENETUNREACH";
	case ENOBUFS:
		return @"ENOBUFS";
	case ENOPROTOOPT:
		return @"ENOPROTOOPT";
	case ENOTCONN:
		return @"ENOTCONN";
	case ENOTSOCK:
		return @"ENOTSOCK";
	case EOPNOTSUPP:
		return @"EOPNOTSUPP";
	case EPFNOSUPPORT:
		return @"EPFNOSUPPORT";
	case EPROCLIM:
		return @"EPROCLIM";
	case EPROTONOSUPPORT:
		return @"EPROTONOSUPPORT";
	case EPROTOTYPE:
		return @"EPROTOTYPE";
	case EREMOTE:
		return @"EREMOTE";
	case ESHUTDOWN:
		return @"ESHUTDOWN";
	case ESOCKTNOSUPPORT:
		return @"ESOCKTNOSUPPORT";
	case ESTALE:
		return @"ESTALE";
	case ETIMEDOUT:
		return @"ETIMEDOUT";
	case ETOOMANYREFS:
		return @"ETOOMANYREFS";
	case EUSERS:
		return @"EUSERS";
	case EWOULDBLOCK:
		return @"EWOULDBLOCK";
	}
#endif

#ifdef HAVE_STRERROR_R
	if (strerror_r(errNo, buffer, 256) != 0)
		return @"Unknown error (strerror_r failed)";

	ret = [OFString stringWithCString: buffer
				 encoding: [OFSystemInfo native8BitEncoding]];
#else
# ifdef OF_HAVE_THREADS
	if (!of_mutex_lock(&mutex))
		@throw [OFLockFailedException exception];

	@try {
# endif
		ret = [OFString
		    stringWithCString: strerror(errNo)
			     encoding: [OFSystemInfo native8BitEncoding]];
# ifdef OF_HAVE_THREADS
	} @finally {
		if (!of_mutex_unlock(&mutex))
			@throw [OFUnlockFailedException exception];
	}
# endif
#endif

	return ret;
}

static _Unwind_Reason_Code
backtrace_callback(struct _Unwind_Context *ctx, void *data)
{
	struct backtrace_ctx *bt = data;

	if (bt->i < OF_BACKTRACE_SIZE) {
# if defined(__arm__) || defined(__ARM__)
		uintptr_t ip;

		_Unwind_VRS_Get(ctx, 0, 15, 0, &ip);
		bt->backtrace[bt->i++] = (void*)(ip & ~1);
# else
		bt->backtrace[bt->i++] = (void*)_Unwind_GetIP(ctx);
# endif
		return _URC_OK;
	}

	return _URC_END_OF_STACK;
}
#endif

@implementation OFException
+ (instancetype)exception
{
	return [[[self alloc] init] autorelease];
}

#ifdef HAVE_DWARF_EXCEPTIONS
- init
{
	struct backtrace_ctx ctx;

	self = [super init];

	ctx.backtrace = _backtrace;
	ctx.i = 0;
	_Unwind_Backtrace(backtrace_callback, &ctx);

	return self;
}
#endif

- (OFString*)description
{
	return [OFString stringWithFormat:
	    @"An exception of type %@ occurred!", [self class]];
}

- (OFArray*)backtrace
{
#ifdef HAVE_DWARF_EXCEPTIONS
	OFMutableArray *backtrace = [OFMutableArray array];
	void *pool = objc_autoreleasePoolPush();
	uint_fast8_t i;

	for (i = 0; i < OF_BACKTRACE_SIZE && _backtrace[i] != NULL; i++) {
# ifdef HAVE_DLADDR
		Dl_info info;

		if (dladdr(_backtrace[i], &info)) {
			OFString *frame;

			if (info.dli_sname != NULL) {
				ptrdiff_t offset = (char*)_backtrace[i] -
				    (char*)info.dli_saddr;

				frame = [OFString stringWithFormat:
				    @"%p <%s+%td> at %s",
				    _backtrace[i], info.dli_sname, offset,
				    info.dli_fname];
			} else
				frame = [OFString stringWithFormat:
				    @"%p <?" @"?> at %s",
				    _backtrace[i], info.dli_fname];

			[backtrace addObject: frame];
		} else
# endif
			[backtrace addObject:
			    [OFString stringWithFormat: @"%p", _backtrace[i]]];
	}

	objc_autoreleasePoolPop(pool);

	[backtrace makeImmutable];

	return backtrace;
#else
	return nil;
#endif
}
@end