2006-12-05 07:55:02 +01:00
|
|
|
/*
|
|
|
|
* Copyright (c) 2003-2005 The Regents of The University of Michigan
|
|
|
|
* All rights reserved.
|
|
|
|
*
|
|
|
|
* Redistribution and use in source and binary forms, with or without
|
|
|
|
* modification, are permitted provided that the following conditions are
|
|
|
|
* met: redistributions of source code must retain the above copyright
|
|
|
|
* notice, this list of conditions and the following disclaimer;
|
|
|
|
* 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;
|
|
|
|
* neither the name of the copyright holders 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 COPYRIGHT HOLDERS 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 COPYRIGHT
|
|
|
|
* OWNER 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.
|
|
|
|
*
|
|
|
|
* Authors: Gabe Black
|
|
|
|
*/
|
|
|
|
|
|
|
|
#ifndef __SIM_SYSCALLRETURN_HH__
|
|
|
|
#define __SIM_SYSCALLRETURN_HH__
|
|
|
|
|
2009-05-17 23:34:51 +02:00
|
|
|
#include "base/types.hh"
|
2006-12-05 07:55:02 +01:00
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
/**
|
|
|
|
* This class represents the return value from an emulated system call,
|
|
|
|
* including any errno setting.
|
|
|
|
*
|
|
|
|
* On some platforms, the return value and errno are encoded in a
|
|
|
|
* single signed integer. A value less than zero but greater than
|
|
|
|
* -4096 indicates an error, and the value is the negation of the
|
|
|
|
* errno value. Otherwise, the call was successful and the integer is
|
|
|
|
* the return value. (Large negative numbers are considered
|
|
|
|
* successful to allow syscalls to return pointers to high memory,
|
|
|
|
* e.g., stack addresses.) See, for example, Appendix A of the AMD64
|
|
|
|
* ABI spec at http://www.x86-64.org/documentation/abi.pdf.
|
|
|
|
*
|
|
|
|
* Other platforms use a more complex interface, returning a value and
|
|
|
|
* an error code in separate registers.
|
|
|
|
*
|
|
|
|
* This class is designed to support both types of interfaces.
|
|
|
|
*/
|
2006-12-05 07:55:02 +01:00
|
|
|
class SyscallReturn
|
|
|
|
{
|
|
|
|
public:
|
2014-05-12 23:23:31 +02:00
|
|
|
|
|
|
|
/// For simplicity, allow the object to be initialized with a
|
|
|
|
/// single signed integer using the same positive=success,
|
|
|
|
/// negative=-errno convention described above.
|
|
|
|
///
|
|
|
|
/// Typically this constructor is used as a default type
|
|
|
|
/// conversion, so a bare integer is used where a SyscallReturn
|
|
|
|
/// value is expected, e.g., as the return value from a system
|
|
|
|
/// call emulation function ('return 0;' or 'return -EFAULT;').
|
|
|
|
SyscallReturn(int64_t v)
|
2014-09-02 23:07:50 +02:00
|
|
|
: value(v), retryFlag(false)
|
2014-05-12 23:23:31 +02:00
|
|
|
{}
|
|
|
|
|
2014-09-02 23:07:50 +02:00
|
|
|
/// Pseudo-constructor to create an instance with the retry flag set.
|
|
|
|
static SyscallReturn retry()
|
|
|
|
{
|
|
|
|
SyscallReturn s(0);
|
|
|
|
s.retryFlag = true;
|
|
|
|
return s;
|
|
|
|
}
|
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
~SyscallReturn() {}
|
|
|
|
|
|
|
|
/// Was the system call successful?
|
|
|
|
bool successful() const
|
2006-12-05 07:55:02 +01:00
|
|
|
{
|
2014-05-12 23:23:31 +02:00
|
|
|
return (value >= 0 || value <= -4096);
|
2006-12-05 07:55:02 +01:00
|
|
|
}
|
|
|
|
|
2014-09-02 23:07:50 +02:00
|
|
|
/// Does the syscall need to be retried?
|
|
|
|
bool needsRetry() const { return retryFlag; }
|
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
/// The return value
|
|
|
|
int64_t returnValue() const
|
2006-12-05 07:55:02 +01:00
|
|
|
{
|
2014-05-12 23:23:31 +02:00
|
|
|
assert(successful());
|
|
|
|
return value;
|
2006-12-05 07:55:02 +01:00
|
|
|
}
|
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
/// The errno value
|
|
|
|
int errnoValue() const
|
|
|
|
{
|
|
|
|
assert(!successful());
|
|
|
|
return -value;
|
|
|
|
}
|
2006-12-05 07:55:02 +01:00
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
/// The encoded value (as described above)
|
|
|
|
int64_t encodedValue() const
|
2006-12-05 07:55:02 +01:00
|
|
|
{
|
2014-05-12 23:23:31 +02:00
|
|
|
return value;
|
2006-12-05 07:55:02 +01:00
|
|
|
}
|
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
private:
|
2006-12-05 07:55:02 +01:00
|
|
|
|
2014-05-12 23:23:31 +02:00
|
|
|
int64_t value;
|
2014-09-02 23:07:50 +02:00
|
|
|
|
|
|
|
bool retryFlag;
|
2006-12-05 07:55:02 +01:00
|
|
|
};
|
|
|
|
|
|
|
|
#endif
|