syscall_emul.hh revision 1354
1/* 2 * Copyright (c) 2003-2004 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#ifndef __SIM_SYSCALL_EMUL_HH__ 30#define __SIM_SYSCALL_EMUL_HH__ 31 32/// 33/// @file syscall_emul.hh 34/// 35/// This file defines objects used to emulate syscalls from the target 36/// application on the host machine. 37 38#include <errno.h> 39#include <string> 40 41#include "base/intmath.hh" // for RoundUp 42#include "mem/functional_mem/functional_memory.hh" 43#include "targetarch/isa_traits.hh" // for Addr 44 45#include "base/trace.hh" 46#include "cpu/exec_context.hh" 47#include "sim/process.hh" 48 49/// 50/// System call descriptor. 51/// 52class SyscallDesc { 53 54 public: 55 56 /// Typedef for target syscall handler functions. 57 typedef int (*FuncPtr)(SyscallDesc *, int num, 58 Process *, ExecContext *); 59 60 const char *name; //!< Syscall name (e.g., "open"). 61 FuncPtr funcPtr; //!< Pointer to emulation function. 62 int flags; //!< Flags (see Flags enum). 63 64 /// Flag values for controlling syscall behavior. 65 enum Flags { 66 /// Don't set return regs according to funcPtr return value. 67 /// Used for syscalls with non-standard return conventions 68 /// that explicitly set the ExecContext regs (e.g., 69 /// sigreturn). 70 SuppressReturnValue = 1 71 }; 72 73 /// Constructor. 74 SyscallDesc(const char *_name, FuncPtr _funcPtr, int _flags = 0) 75 : name(_name), funcPtr(_funcPtr), flags(_flags) 76 { 77 } 78 79 /// Emulate the syscall. Public interface for calling through funcPtr. 80 void doSyscall(int callnum, Process *proc, ExecContext *xc); 81}; 82 83 84class BaseBufferArg { 85 86 public: 87 88 BaseBufferArg(Addr _addr, int _size) : addr(_addr), size(_size) 89 { 90 bufPtr = new uint8_t[size]; 91 // clear out buffer: in case we only partially populate this, 92 // and then do a copyOut(), we want to make sure we don't 93 // introduce any random junk into the simulated address space 94 memset(bufPtr, 0, size); 95 } 96 97 virtual ~BaseBufferArg() { delete [] bufPtr; } 98 99 // 100 // copy data into simulator space (read from target memory) 101 // 102 virtual bool copyIn(FunctionalMemory *mem) 103 { 104 mem->access(Read, addr, bufPtr, size); 105 return true; // no EFAULT detection for now 106 } 107 108 // 109 // copy data out of simulator space (write to target memory) 110 // 111 virtual bool copyOut(FunctionalMemory *mem) 112 { 113 mem->access(Write, addr, bufPtr, size); 114 return true; // no EFAULT detection for now 115 } 116 117 protected: 118 Addr addr; 119 int size; 120 uint8_t *bufPtr; 121}; 122 123 124class BufferArg : public BaseBufferArg 125{ 126 public: 127 BufferArg(Addr _addr, int _size) : BaseBufferArg(_addr, _size) { } 128 void *bufferPtr() { return bufPtr; } 129}; 130 131template <class T> 132class TypedBufferArg : public BaseBufferArg 133{ 134 public: 135 // user can optionally specify a specific number of bytes to 136 // allocate to deal with those structs that have variable-size 137 // arrays at the end 138 TypedBufferArg(Addr _addr, int _size = sizeof(T)) 139 : BaseBufferArg(_addr, _size) 140 { } 141 142 // type case 143 operator T*() { return (T *)bufPtr; } 144 145 // dereference operators 146 T &operator*() { return *((T *)bufPtr); } 147 T* operator->() { return (T *)bufPtr; } 148 T &operator[](int i) { return ((T *)bufPtr)[i]; } 149}; 150 151////////////////////////////////////////////////////////////////////// 152// 153// The following emulation functions are generic enough that they 154// don't need to be recompiled for different emulated OS's. They are 155// defined in sim/syscall_emul.cc. 156// 157////////////////////////////////////////////////////////////////////// 158 159 160/// Handler for unimplemented syscalls that we haven't thought about. 161int unimplementedFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 162 163/// Handler for unimplemented syscalls that we never intend to 164/// implement (signal handling, etc.) and should not affect the correct 165/// behavior of the program. Print a warning only if the appropriate 166/// trace flag is enabled. Return success to the target program. 167int ignoreFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 168 169/// Target exit() handler: terminate simulation. 170int exitFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 171 172/// Target getpagesize() handler. 173int getpagesizeFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 174 175/// Target obreak() handler: set brk address. 176int obreakFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 177 178/// Target close() handler. 179int closeFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 180 181/// Target read() handler. 182int readFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 183 184/// Target write() handler. 185int writeFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 186 187/// Target lseek() handler. 188int lseekFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 189 190/// Target munmap() handler. 191int munmapFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 192 193/// Target gethostname() handler. 194int gethostnameFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 195 196/// Target unlink() handler. 197int unlinkFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 198 199/// Target rename() handler. 200int renameFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc); 201 202/// This struct is used to build an target-OS-dependent table that 203/// maps the target's open() flags to the host open() flags. 204struct OpenFlagTransTable { 205 int tgtFlag; //!< Target system flag value. 206 int hostFlag; //!< Corresponding host system flag value. 207}; 208 209 210 211/// A readable name for 1,000,000, for converting microseconds to seconds. 212const int one_million = 1000000; 213 214/// Approximate seconds since the epoch (1/1/1970). About a billion, 215/// by my reckoning. We want to keep this a constant (not use the 216/// real-world time) to keep simulations repeatable. 217const unsigned seconds_since_epoch = 1000000000; 218 219/// Helper function to convert current elapsed time to seconds and 220/// microseconds. 221template <class T1, class T2> 222void 223getElapsedTime(T1 &sec, T2 &usec) 224{ 225 int cycles_per_usec = ticksPerSecond / one_million; 226 227 int elapsed_usecs = curTick / cycles_per_usec; 228 sec = elapsed_usecs / one_million; 229 usec = elapsed_usecs % one_million; 230} 231 232////////////////////////////////////////////////////////////////////// 233// 234// The following emulation functions are generic, but need to be 235// templated to account for differences in types, constants, etc. 236// 237////////////////////////////////////////////////////////////////////// 238 239/// Target ioctl() handler. For the most part, programs call ioctl() 240/// only to find out if their stdout is a tty, to determine whether to 241/// do line or block buffering. 242template <class OS> 243int 244ioctlFunc(SyscallDesc *desc, int callnum, Process *process, 245 ExecContext *xc) 246{ 247 int fd = xc->getSyscallArg(0); 248 unsigned req = xc->getSyscallArg(1); 249 250 // DPRINTFR(SyscallVerbose, "ioctl(%d, 0x%x, ...)\n", fd, req); 251 252 if (fd < 0 || process->sim_fd(fd) < 0) { 253 // doesn't map to any simulator fd: not a valid target fd 254 return -EBADF; 255 } 256 257 switch (req) { 258 case OS::TIOCISATTY: 259 case OS::TIOCGETP: 260 case OS::TIOCSETP: 261 case OS::TIOCSETN: 262 case OS::TIOCSETC: 263 case OS::TIOCGETC: 264 case OS::TIOCGETS: 265 case OS::TIOCGETA: 266 return -ENOTTY; 267 268 default: 269 fatal("Unsupported ioctl call: ioctl(%d, 0x%x, ...) @ 0x%llx\n", fd, req, xc->readPC()); 270 } 271} 272 273/// Target open() handler. 274template <class OS> 275int 276openFunc(SyscallDesc *desc, int callnum, Process *process, 277 ExecContext *xc) 278{ 279 std::string path; 280 281 if (xc->mem->readString(path, xc->getSyscallArg(0)) != No_Fault) 282 return -EFAULT; 283 284 if (path == "/dev/sysdev0") { 285 // This is a memory-mapped high-resolution timer device on Alpha. 286 // We don't support it, so just punt. 287 DCOUT(SyscallWarnings) << "Ignoring open(" << path << ", ...)" << std::endl; 288 return -ENOENT; 289 } 290 291 int tgtFlags = xc->getSyscallArg(1); 292 int mode = xc->getSyscallArg(2); 293 int hostFlags = 0; 294 295 // translate open flags 296 for (int i = 0; i < OS::NUM_OPEN_FLAGS; i++) { 297 if (tgtFlags & OS::openFlagTable[i].tgtFlag) { 298 tgtFlags &= ~OS::openFlagTable[i].tgtFlag; 299 hostFlags |= OS::openFlagTable[i].hostFlag; 300 } 301 } 302 303 // any target flags left? 304 if (tgtFlags != 0) 305 std::cerr << "Syscall: open: cannot decode flags: " << tgtFlags << std::endl; 306 307#ifdef __CYGWIN32__ 308 hostFlags |= O_BINARY; 309#endif 310 311 // open the file 312 int fd = open(path.c_str(), hostFlags, mode); 313 314 return (fd == -1) ? -errno : process->open_fd(fd); 315} 316 317 318/// Target stat() handler. 319template <class OS> 320int 321statFunc(SyscallDesc *desc, int callnum, Process *process, 322 ExecContext *xc) 323{ 324 std::string path; 325 326 if (xc->mem->readString(path, xc->getSyscallArg(0)) != No_Fault) 327 return -EFAULT; 328 329 struct stat hostBuf; 330 int result = stat(path.c_str(), &hostBuf); 331 332 if (result < 0) 333 return -errno; 334 335 OS::copyOutStatBuf(xc->mem, xc->getSyscallArg(1), &hostBuf); 336 337 return 0; 338} 339 340 341/// Target lstat() handler. 342template <class OS> 343int 344lstatFunc(SyscallDesc *desc, int callnum, Process *process, 345 ExecContext *xc) 346{ 347 std::string path; 348 349 if (xc->mem->readString(path, xc->getSyscallArg(0)) != No_Fault) 350 return -EFAULT; 351 352 struct stat hostBuf; 353 int result = lstat(path.c_str(), &hostBuf); 354 355 if (result < 0) 356 return -errno; 357 358 OS::copyOutStatBuf(xc->mem, xc->getSyscallArg(1), &hostBuf); 359 360 return 0; 361} 362 363/// Target fstat() handler. 364template <class OS> 365int 366fstatFunc(SyscallDesc *desc, int callnum, Process *process, 367 ExecContext *xc) 368{ 369 int fd = process->sim_fd(xc->getSyscallArg(0)); 370 371 // DPRINTFR(SyscallVerbose, "fstat(%d, ...)\n", fd); 372 373 if (fd < 0) 374 return -EBADF; 375 376 struct stat hostBuf; 377 int result = fstat(fd, &hostBuf); 378 379 if (result < 0) 380 return -errno; 381 382 OS::copyOutStatBuf(xc->mem, xc->getSyscallArg(1), &hostBuf); 383 384 return 0; 385} 386 387 388/// Target mmap() handler. 389/// 390/// We don't really handle mmap(). If the target is mmaping an 391/// anonymous region or /dev/zero, we can get away with doing basically 392/// nothing (since memory is initialized to zero and the simulator 393/// doesn't really check addresses anyway). Always print a warning, 394/// since this could be seriously broken if we're not mapping 395/// /dev/zero. 396// 397/// Someday we should explicitly check for /dev/zero in open, flag the 398/// file descriptor, and fail (or implement!) a non-anonymous mmap to 399/// anything else. 400template <class OS> 401int 402mmapFunc(SyscallDesc *desc, int num, Process *p, ExecContext *xc) 403{ 404 Addr start = xc->getSyscallArg(0); 405 uint64_t length = xc->getSyscallArg(1); 406 // int prot = xc->getSyscallArg(2); 407 int flags = xc->getSyscallArg(3); 408 // int fd = p->sim_fd(xc->getSyscallArg(4)); 409 // int offset = xc->getSyscallArg(5); 410 411 if (start == 0) { 412 // user didn't give an address... pick one from our "mmap region" 413 start = p->mmap_base; 414 p->mmap_base += RoundUp<Addr>(length, VMPageSize); 415 } 416 417 if (!(flags & OS::TGT_MAP_ANONYMOUS)) { 418 DPRINTF(SyscallWarnings, "Warning: allowing mmap of file @ fd %d. " 419 "This will break if not /dev/zero.", xc->getSyscallArg(4)); 420 } 421 422 return start; 423} 424 425/// Target getrlimit() handler. 426template <class OS> 427int 428getrlimitFunc(SyscallDesc *desc, int callnum, Process *process, 429 ExecContext *xc) 430{ 431 unsigned resource = xc->getSyscallArg(0); 432 TypedBufferArg<typename OS::rlimit> rlp(xc->getSyscallArg(1)); 433 434 switch (resource) { 435 case OS::RLIMIT_STACK: 436 // max stack size in bytes: make up a number (2MB for now) 437 rlp->rlim_cur = rlp->rlim_max = 8 * 1024 * 1024; 438 break; 439 440 default: 441 std::cerr << "getrlimitFunc: unimplemented resource " << resource << std::endl; 442 abort(); 443 break; 444 } 445 446 rlp.copyOut(xc->mem); 447 return 0; 448} 449 450/// Target gettimeofday() handler. 451template <class OS> 452int 453gettimeofdayFunc(SyscallDesc *desc, int callnum, Process *process, 454 ExecContext *xc) 455{ 456 TypedBufferArg<typename OS::timeval> tp(xc->getSyscallArg(0)); 457 458 getElapsedTime(tp->tv_sec, tp->tv_usec); 459 tp->tv_sec += seconds_since_epoch; 460 461 tp.copyOut(xc->mem); 462 463 return 0; 464} 465 466 467/// Target getrusage() function. 468template <class OS> 469int 470getrusageFunc(SyscallDesc *desc, int callnum, Process *process, 471 ExecContext *xc) 472{ 473 int who = xc->getSyscallArg(0); // THREAD, SELF, or CHILDREN 474 TypedBufferArg<typename OS::rusage> rup(xc->getSyscallArg(1)); 475 476 if (who != OS::RUSAGE_SELF) { 477 // don't really handle THREAD or CHILDREN, but just warn and 478 // plow ahead 479 DCOUT(SyscallWarnings) 480 << "Warning: getrusage() only supports RUSAGE_SELF." 481 << " Parameter " << who << " ignored." << std::endl; 482 } 483 484 getElapsedTime(rup->ru_utime.tv_sec, rup->ru_utime.tv_usec); 485 rup->ru_stime.tv_sec = 0; 486 rup->ru_stime.tv_usec = 0; 487 rup->ru_maxrss = 0; 488 rup->ru_ixrss = 0; 489 rup->ru_idrss = 0; 490 rup->ru_isrss = 0; 491 rup->ru_minflt = 0; 492 rup->ru_majflt = 0; 493 rup->ru_nswap = 0; 494 rup->ru_inblock = 0; 495 rup->ru_oublock = 0; 496 rup->ru_msgsnd = 0; 497 rup->ru_msgrcv = 0; 498 rup->ru_nsignals = 0; 499 rup->ru_nvcsw = 0; 500 rup->ru_nivcsw = 0; 501 502 rup.copyOut(xc->mem); 503 504 return 0; 505} 506 507#endif // __SIM_SYSCALL_EMUL_HH__ 508