gem5/sim/syscall_emul.hh
Steve Reinhardt 9984b2bd6c Formatting & doxygen docs for new syscall emulation code.
arch/alpha/alpha_linux_process.cc:
arch/alpha/alpha_linux_process.hh:
arch/alpha/alpha_tru64_process.cc:
arch/alpha/alpha_tru64_process.hh:
sim/syscall_emul.cc:
sim/syscall_emul.hh:
    Formatting & doxygen.

--HG--
extra : convert_revision : 4f07dd37e254120800dd0d5c0eb47acc9c00cb3f
2003-12-01 22:39:27 -08:00

499 lines
14 KiB
C++

/*
* Copyright (c) 2003 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.
*/
#ifndef __SYSCALL_EMUL_HH__
#define __SYSCALL_EMUL_HH__
///
/// @file syscall_emul.hh
///
/// This file defines objects used to emulate syscalls from the target
/// application on the host machine.
#include <string>
#include "base/intmath.hh" // for RoundUp
#include "targetarch/isa_traits.hh" // for Addr
#include "mem/functional_mem/functional_memory.hh"
class Process;
class ExecContext;
///
/// System call descriptor.
///
class SyscallDesc {
public:
/// Typedef for target syscall handler functions.
typedef int (*FuncPtr)(SyscallDesc *, int num,
Process *, ExecContext *);
const char *name; //!< Syscall name (e.g., "open").
FuncPtr funcPtr; //!< Pointer to emulation function.
int flags; //!< Flags (see Flags enum).
/// Flag values for controlling syscall behavior.
enum Flags {
/// Don't set return regs according to funcPtr return value.
/// Used for syscalls with non-standard return conventions
/// that explicitly set the ExecContext regs (e.g.,
/// sigreturn).
SuppressReturnValue = 1
};
/// Constructor.
SyscallDesc(const char *_name, FuncPtr _funcPtr, int _flags = 0)
: name(_name), funcPtr(_funcPtr), flags(_flags)
{
}
/// Emulate the syscall. Public interface for calling through funcPtr.
void doSyscall(int callnum, Process *proc, ExecContext *xc);
};
class BaseBufferArg {
public:
BaseBufferArg(Addr _addr, int _size) : addr(_addr), size(_size)
{
bufPtr = new uint8_t[size];
// clear out buffer: in case we only partially populate this,
// and then do a copyOut(), we want to make sure we don't
// introduce any random junk into the simulated address space
memset(bufPtr, 0, size);
}
virtual ~BaseBufferArg() { delete [] bufPtr; }
//
// copy data into simulator space (read from target memory)
//
virtual bool copyIn(FunctionalMemory *mem)
{
mem->access(Read, addr, bufPtr, size);
return true; // no EFAULT detection for now
}
//
// copy data out of simulator space (write to target memory)
//
virtual bool copyOut(FunctionalMemory *mem)
{
mem->access(Write, addr, bufPtr, size);
return true; // no EFAULT detection for now
}
protected:
Addr addr;
int size;
uint8_t *bufPtr;
};
class BufferArg : public BaseBufferArg
{
public:
BufferArg(Addr _addr, int _size) : BaseBufferArg(_addr, _size) { }
void *bufferPtr() { return bufPtr; }
};
template <class T>
class TypedBufferArg : public BaseBufferArg
{
public:
// user can optionally specify a specific number of bytes to
// allocate to deal with those structs that have variable-size
// arrays at the end
TypedBufferArg(Addr _addr, int _size = sizeof(T))
: BaseBufferArg(_addr, _size)
{ }
// type case
operator T*() { return (T *)bufPtr; }
// dereference operators
T& operator*() { return *((T *)bufPtr); }
T* operator->() { return (T *)bufPtr; }
T& operator[](int i) { return ((T *)bufPtr)[i]; }
};
//////////////////////////////////////////////////////////////////////
//
// The following emulation functions are generic enough that they
// don't need to be recompiled for different emulated OS's. They are
// defined in sim/syscall_emul.cc.
//
//////////////////////////////////////////////////////////////////////
/// Handler for unimplemented syscalls that we haven't thought about.
int unimplementedFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Handler for unimplemented syscalls that we never intend to
/// implement (signal handling, etc.) and should not affect the correct
/// behavior of the program. Print a warning only if the appropriate
/// trace flag is enabled. Return success to the target program.
int ignoreFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target exit() handler: terminate simulation.
int exitFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target getpagesize() handler.
int getpagesizeFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target obreak() handler: set brk address.
int obreakFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target close() handler.
int closeFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target read() handler.
int readFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target write() handler.
int writeFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target lseek() handler.
int lseekFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target munmap() handler.
int munmapFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
/// Target gethostname() handler.
int gethostnameFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc);
//////////////////////////////////////////////////////////////////////
//
// The following emulation functions are generic, but need to be
// templated to account for differences in types, constants, etc.
//
//////////////////////////////////////////////////////////////////////
/// Target ioctl() handler. For the most part, programs call ioctl()
/// only to find out if their stdout is a tty, to determine whether to
/// do line or block buffering.
template <class OS>
int
ioctlFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
int fd = xc->getSyscallArg(0);
unsigned req = xc->getSyscallArg(1);
// DPRINTFR(SyscallVerbose, "ioctl(%d, 0x%x, ...)\n", fd, req);
if (fd < 0 || process->sim_fd(fd) < 0) {
// doesn't map to any simulator fd: not a valid target fd
return -EBADF;
}
switch (req) {
case OS::TIOCISATTY:
case OS::TIOCGETP:
case OS::TIOCSETP:
case OS::TIOCSETN:
case OS::TIOCSETC:
case OS::TIOCGETC:
return -ENOTTY;
default:
fatal("Unsupported ioctl call: ioctl(%d, 0x%x, ...)\n", fd, req);
}
}
/// This struct is used to build an target-OS-dependent table that
/// maps the target's open() flags to the host open() flags.
struct OpenFlagTransTable {
int tgtFlag; //!< Target system flag value.
int hostFlag; //!< Corresponding host system flag value.
};
/// Target open() handler.
template <class OS>
int
openFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
std::string path;
if (xc->mem->readString(path, xc->getSyscallArg(0)) != No_Fault)
return -EFAULT;
if (path == "/dev/sysdev0") {
// This is a memory-mapped high-resolution timer device on Alpha.
// We don't support it, so just punt.
DCOUT(SyscallWarnings) << "Ignoring open(" << path << ", ...)" << endl;
return -ENOENT;
}
int tgtFlags = xc->getSyscallArg(1);
int mode = xc->getSyscallArg(2);
int hostFlags = 0;
// translate open flags
for (int i = 0; i < OS::NUM_OPEN_FLAGS; i++) {
if (tgtFlags & OS::openFlagTable[i].tgtFlag) {
tgtFlags &= ~OS::openFlagTable[i].tgtFlag;
hostFlags |= OS::openFlagTable[i].hostFlag;
}
}
// any target flags left?
if (tgtFlags != 0)
cerr << "Syscall: open: cannot decode flags: " << tgtFlags << endl;
#ifdef __CYGWIN32__
hostFlags |= O_BINARY;
#endif
// open the file
int fd = open(path.c_str(), hostFlags, mode);
return (fd == -1) ? -errno : process->open_fd(fd);
}
/// Target stat() handler.
template <class OS>
int
statFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
std::string path;
if (xc->mem->readString(path, xc->getSyscallArg(0)) != No_Fault)
return -EFAULT;
struct stat hostBuf;
int result = stat(path.c_str(), &hostBuf);
if (result < 0)
return -errno;
OS::copyOutStatBuf(xc->mem, xc->getSyscallArg(1), &hostBuf);
return 0;
}
/// Target lstat() handler.
template <class OS>
int
lstatFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
std::string path;
if (xc->mem->readString(path, xc->getSyscallArg(0)) != No_Fault)
return -EFAULT;
struct stat hostBuf;
int result = lstat(path.c_str(), &hostBuf);
if (result < 0)
return -errno;
OS::copyOutStatBuf(xc->mem, xc->getSyscallArg(1), &hostBuf);
return 0;
}
/// Target fstat() handler.
template <class OS>
int
fstatFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
int fd = process->sim_fd(xc->getSyscallArg(0));
// DPRINTFR(SyscallVerbose, "fstat(%d, ...)\n", fd);
if (fd < 0)
return -EBADF;
struct stat hostBuf;
int result = fstat(fd, &hostBuf);
if (result < 0)
return -errno;
OS::copyOutStatBuf(xc->mem, xc->getSyscallArg(1), &hostBuf);
return 0;
}
/// Target mmap() handler.
///
/// We don't really handle mmap(). If the target is mmaping an
/// anonymous region or /dev/zero, we can get away with doing basically
/// nothing (since memory is initialized to zero and the simulator
/// doesn't really check addresses anyway). Always print a warning,
/// since this could be seriously broken if we're not mapping
/// /dev/zero.
//
/// Someday we should explicitly check for /dev/zero in open, flag the
/// file descriptor, and fail (or implement!) a non-anonymous mmap to
/// anything else.
template <class OS>
int
mmapFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc)
{
Addr start = xc->getSyscallArg(0);
uint64_t length = xc->getSyscallArg(1);
// int prot = xc->getSyscallArg(2);
int flags = xc->getSyscallArg(3);
// int fd = p->sim_fd(xc->getSyscallArg(4));
// int offset = xc->getSyscallArg(5);
if (start == 0) {
// user didn't give an address... pick one from our "mmap region"
start = p->mmap_base;
p->mmap_base += RoundUp<Addr>(length, VMPageSize);
}
if (!(flags & OS::TGT_MAP_ANONYMOUS)) {
DPRINTF(SyscallWarnings, "Warning: allowing mmap of file @ fd %d. "
"This will break if not /dev/zero.", xc->getSyscallArg(4));
}
return start;
}
/// Target getrlimit() handler.
template <class OS>
int
getrlimitFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
unsigned resource = xc->getSyscallArg(0);
TypedBufferArg<typename OS::rlimit> rlp(xc->getSyscallArg(1));
switch (resource) {
case OS::RLIMIT_STACK:
// max stack size in bytes: make up a number (2MB for now)
rlp->rlim_cur = rlp->rlim_max = 8 * 1024 * 1024;
break;
default:
cerr << "getrlimitFunc: unimplemented resource " << resource << endl;
abort();
break;
}
rlp.copyOut(xc->mem);
return 0;
}
/// A readable name for 1,000,000, for converting microseconds to seconds.
const int one_million = 1000000;
/// Approximate seconds since the epoch (1/1/1970). About a billion,
/// by my reckoning. We want to keep this a constant (not use the
/// real-world time) to keep simulations repeatable.
const unsigned seconds_since_epoch = 1000000000;
/// Helper function to convert current elapsed time to seconds and
/// microseconds.
template <class T1, class T2>
void
getElapsedTime(T1 &sec, T2 &usec)
{
int cycles_per_usec = ticksPerSecond / one_million;
int elapsed_usecs = curTick / cycles_per_usec;
sec = elapsed_usecs / one_million;
usec = elapsed_usecs % one_million;
}
/// Target gettimeofday() handler.
template <class OS>
int
gettimeofdayFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
TypedBufferArg<typename OS::timeval> tp(xc->getSyscallArg(0));
getElapsedTime(tp->tv_sec, tp->tv_usec);
tp->tv_sec += seconds_since_epoch;
tp.copyOut(xc->mem);
return 0;
}
/// Target getrusage() function.
template <class OS>
int
getrusageFunc(SyscallDesc *desc, int callnum, Process *process,
ExecContext *xc)
{
int who = xc->getSyscallArg(0); // THREAD, SELF, or CHILDREN
TypedBufferArg<typename OS::rusage> rup(xc->getSyscallArg(1));
if (who != OS::RUSAGE_SELF) {
// don't really handle THREAD or CHILDREN, but just warn and
// plow ahead
DCOUT(SyscallWarnings)
<< "Warning: getrusage() only supports RUSAGE_SELF."
<< " Parameter " << who << " ignored." << endl;
}
getElapsedTime(rup->ru_utime.tv_sec, rup->ru_utime.tv_usec);
rup->ru_stime.tv_sec = 0;
rup->ru_stime.tv_usec = 0;
rup->ru_maxrss = 0;
rup->ru_ixrss = 0;
rup->ru_idrss = 0;
rup->ru_isrss = 0;
rup->ru_minflt = 0;
rup->ru_majflt = 0;
rup->ru_nswap = 0;
rup->ru_inblock = 0;
rup->ru_oublock = 0;
rup->ru_msgsnd = 0;
rup->ru_msgrcv = 0;
rup->ru_nsignals = 0;
rup->ru_nvcsw = 0;
rup->ru_nivcsw = 0;
rup.copyOut(xc->mem);
return 0;
}
#endif // __SYSCALL_EMUL_HH__