syscall_emul.cc revision 2680 
1/*
2 * Copyright (c) 2003-2005 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 * Authors: Steve Reinhardt
29 *          Ali Saidi
30 */
31
32#include <fcntl.h>
33#include <unistd.h>
34
35#include <string>
36#include <iostream>
37
38#include "sim/syscall_emul.hh"
39#include "base/chunk_generator.hh"
40#include "base/trace.hh"
41#include "cpu/thread_context.hh"
42#include "cpu/base.hh"
43#include "mem/page_table.hh"
44#include "sim/process.hh"
45
46#include "sim/sim_events.hh"
47
48using namespace std;
49using namespace TheISA;
50
51void
52SyscallDesc::doSyscall(int callnum, Process *process, ThreadContext *tc)
53{
54    DPRINTFR(SyscallVerbose, "%d: %s: syscall %s called w/arguments %d,%d,%d,%d\n",
55             curTick,tc->getCpuPtr()->name(), name,
56             tc->getSyscallArg(0),tc->getSyscallArg(1),
57             tc->getSyscallArg(2),tc->getSyscallArg(3));
58
59    SyscallReturn retval = (*funcPtr)(this, callnum, process, tc);
60
61    DPRINTFR(SyscallVerbose, "%d: %s: syscall %s returns %d\n",
62             curTick,tc->getCpuPtr()->name(), name, retval.value());
63
64    if (!(flags & SyscallDesc::SuppressReturnValue))
65        tc->setSyscallReturn(retval);
66}
67
68
69SyscallReturn
70unimplementedFunc(SyscallDesc *desc, int callnum, Process *process,
71                  ThreadContext *tc)
72{
73    fatal("syscall %s (#%d) unimplemented.", desc->name, callnum);
74
75    return 1;
76}
77
78
79SyscallReturn
80ignoreFunc(SyscallDesc *desc, int callnum, Process *process,
81           ThreadContext *tc)
82{
83    warn("ignoring syscall %s(%d, %d, ...)", desc->name,
84         tc->getSyscallArg(0), tc->getSyscallArg(1));
85
86    return 0;
87}
88
89
90SyscallReturn
91exitFunc(SyscallDesc *desc, int callnum, Process *process,
92         ThreadContext *tc)
93{
94    new SimExitEvent("target called exit()", tc->getSyscallArg(0) & 0xff);
95
96    return 1;
97}
98
99
100SyscallReturn
101getpagesizeFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
102{
103    return (int)VMPageSize;
104}
105
106
107SyscallReturn
108obreakFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
109{
110    Addr junk;
111
112    // change brk addr to first arg
113    Addr new_brk = tc->getSyscallArg(0);
114    if (new_brk != 0) {
115        for (ChunkGenerator gen(p->brk_point, new_brk - p->brk_point,
116                                VMPageSize); !gen.done(); gen.next()) {
117            if (!p->pTable->translate(gen.addr(), junk))
118                p->pTable->allocate(roundDown(gen.addr(), VMPageSize),
119                                    VMPageSize);
120        }
121        p->brk_point = new_brk;
122    }
123    DPRINTF(SyscallVerbose, "Break Point changed to: %#X\n", p->brk_point);
124    return p->brk_point;
125}
126
127
128SyscallReturn
129closeFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
130{
131    int target_fd = tc->getSyscallArg(0);
132    int status = close(p->sim_fd(target_fd));
133    if (status >= 0)
134        p->free_fd(target_fd);
135    return status;
136}
137
138
139SyscallReturn
140readFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
141{
142    int fd = p->sim_fd(tc->getSyscallArg(0));
143    int nbytes = tc->getSyscallArg(2);
144    BufferArg bufArg(tc->getSyscallArg(1), nbytes);
145
146    int bytes_read = read(fd, bufArg.bufferPtr(), nbytes);
147
148    if (bytes_read != -1)
149        bufArg.copyOut(tc->getMemPort());
150
151    return bytes_read;
152}
153
154SyscallReturn
155writeFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
156{
157    int fd = p->sim_fd(tc->getSyscallArg(0));
158    int nbytes = tc->getSyscallArg(2);
159    BufferArg bufArg(tc->getSyscallArg(1), nbytes);
160
161    bufArg.copyIn(tc->getMemPort());
162
163    int bytes_written = write(fd, bufArg.bufferPtr(), nbytes);
164
165    fsync(fd);
166
167    return bytes_written;
168}
169
170
171SyscallReturn
172lseekFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
173{
174    int fd = p->sim_fd(tc->getSyscallArg(0));
175    uint64_t offs = tc->getSyscallArg(1);
176    int whence = tc->getSyscallArg(2);
177
178    off_t result = lseek(fd, offs, whence);
179
180    return (result == (off_t)-1) ? -errno : result;
181}
182
183
184SyscallReturn
185munmapFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
186{
187    // given that we don't really implement mmap, munmap is really easy
188    return 0;
189}
190
191
192const char *hostname = "m5.eecs.umich.edu";
193
194SyscallReturn
195gethostnameFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
196{
197    int name_len = tc->getSyscallArg(1);
198    BufferArg name(tc->getSyscallArg(0), name_len);
199
200    strncpy((char *)name.bufferPtr(), hostname, name_len);
201
202    name.copyOut(tc->getMemPort());
203
204    return 0;
205}
206
207SyscallReturn
208unlinkFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
209{
210    string path;
211
212    if (!tc->getMemPort()->tryReadString(path, tc->getSyscallArg(0)))
213        return (TheISA::IntReg)-EFAULT;
214
215    int result = unlink(path.c_str());
216    return (result == -1) ? -errno : result;
217}
218
219SyscallReturn
220renameFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
221{
222    string old_name;
223
224    if (!tc->getMemPort()->tryReadString(old_name, tc->getSyscallArg(0)))
225        return -EFAULT;
226
227    string new_name;
228
229    if (!tc->getMemPort()->tryReadString(new_name, tc->getSyscallArg(1)))
230        return -EFAULT;
231
232    int64_t result = rename(old_name.c_str(), new_name.c_str());
233    return (result == -1) ? -errno : result;
234}
235
236SyscallReturn
237truncateFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
238{
239    string path;
240
241    if (!tc->getMemPort()->tryReadString(path, tc->getSyscallArg(0)))
242        return -EFAULT;
243
244    off_t length = tc->getSyscallArg(1);
245
246    int result = truncate(path.c_str(), length);
247    return (result == -1) ? -errno : result;
248}
249
250SyscallReturn
251ftruncateFunc(SyscallDesc *desc, int num, Process *process, ThreadContext *tc)
252{
253    int fd = process->sim_fd(tc->getSyscallArg(0));
254
255    if (fd < 0)
256        return -EBADF;
257
258    off_t length = tc->getSyscallArg(1);
259
260    int result = ftruncate(fd, length);
261    return (result == -1) ? -errno : result;
262}
263
264SyscallReturn
265chownFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
266{
267    string path;
268
269    if (!tc->getMemPort()->tryReadString(path, tc->getSyscallArg(0)))
270        return -EFAULT;
271
272    /* XXX endianess */
273    uint32_t owner = tc->getSyscallArg(1);
274    uid_t hostOwner = owner;
275    uint32_t group = tc->getSyscallArg(2);
276    gid_t hostGroup = group;
277
278    int result = chown(path.c_str(), hostOwner, hostGroup);
279    return (result == -1) ? -errno : result;
280}
281
282SyscallReturn
283fchownFunc(SyscallDesc *desc, int num, Process *process, ThreadContext *tc)
284{
285    int fd = process->sim_fd(tc->getSyscallArg(0));
286
287    if (fd < 0)
288        return -EBADF;
289
290    /* XXX endianess */
291    uint32_t owner = tc->getSyscallArg(1);
292    uid_t hostOwner = owner;
293    uint32_t group = tc->getSyscallArg(2);
294    gid_t hostGroup = group;
295
296    int result = fchown(fd, hostOwner, hostGroup);
297    return (result == -1) ? -errno : result;
298}
299
300
301SyscallReturn
302fcntlFunc(SyscallDesc *desc, int num, Process *process,
303          ThreadContext *tc)
304{
305    int fd = tc->getSyscallArg(0);
306
307    if (fd < 0 || process->sim_fd(fd) < 0)
308        return -EBADF;
309
310    int cmd = tc->getSyscallArg(1);
311    switch (cmd) {
312      case 0: // F_DUPFD
313        // if we really wanted to support this, we'd need to do it
314        // in the target fd space.
315        warn("fcntl(%d, F_DUPFD) not supported, error returned\n", fd);
316        return -EMFILE;
317
318      case 1: // F_GETFD (get close-on-exec flag)
319      case 2: // F_SETFD (set close-on-exec flag)
320        return 0;
321
322      case 3: // F_GETFL (get file flags)
323      case 4: // F_SETFL (set file flags)
324        // not sure if this is totally valid, but we'll pass it through
325        // to the underlying OS
326        warn("fcntl(%d, %d) passed through to host\n", fd, cmd);
327        return fcntl(process->sim_fd(fd), cmd);
328        // return 0;
329
330      case 7: // F_GETLK  (get lock)
331      case 8: // F_SETLK  (set lock)
332      case 9: // F_SETLKW (set lock and wait)
333        // don't mess with file locking... just act like it's OK
334        warn("File lock call (fcntl(%d, %d)) ignored.\n", fd, cmd);
335        return 0;
336
337      default:
338        warn("Unknown fcntl command %d\n", cmd);
339        return 0;
340    }
341}
342
343SyscallReturn
344pipePseudoFunc(SyscallDesc *desc, int callnum, Process *process,
345         ThreadContext *tc)
346{
347    int fds[2], sim_fds[2];
348    int pipe_retval = pipe(fds);
349
350    if (pipe_retval < 0) {
351        // error
352        return pipe_retval;
353    }
354
355    sim_fds[0] = process->alloc_fd(fds[0]);
356    sim_fds[1] = process->alloc_fd(fds[1]);
357
358    // Alpha Linux convention for pipe() is that fd[0] is returned as
359    // the return value of the function, and fd[1] is returned in r20.
360    tc->setIntReg(SyscallPseudoReturnReg, sim_fds[1]);
361    return sim_fds[0];
362}
363
364
365SyscallReturn
366getpidPseudoFunc(SyscallDesc *desc, int callnum, Process *process,
367           ThreadContext *tc)
368{
369    // Make up a PID.  There's no interprocess communication in
370    // fake_syscall mode, so there's no way for a process to know it's
371    // not getting a unique value.
372
373    tc->setIntReg(SyscallPseudoReturnReg, 99);
374    return 100;
375}
376
377
378SyscallReturn
379getuidPseudoFunc(SyscallDesc *desc, int callnum, Process *process,
380           ThreadContext *tc)
381{
382    // Make up a UID and EUID... it shouldn't matter, and we want the
383    // simulation to be deterministic.
384
385    // EUID goes in r20.
386    tc->setIntReg(SyscallPseudoReturnReg, 100); //EUID
387    return 100;		// UID
388}
389
390
391SyscallReturn
392getgidPseudoFunc(SyscallDesc *desc, int callnum, Process *process,
393           ThreadContext *tc)
394{
395    // Get current group ID.  EGID goes in r20.
396    tc->setIntReg(SyscallPseudoReturnReg, 100); //EGID
397    return 100;
398}
399
400
401SyscallReturn
402setuidFunc(SyscallDesc *desc, int callnum, Process *process,
403           ThreadContext *tc)
404{
405    // can't fathom why a benchmark would call this.
406    warn("Ignoring call to setuid(%d)\n", tc->getSyscallArg(0));
407    return 0;
408}
409
410SyscallReturn
411getpidFunc(SyscallDesc *desc, int callnum, Process *process,
412           ThreadContext *tc)
413{
414    // Make up a PID.  There's no interprocess communication in
415    // fake_syscall mode, so there's no way for a process to know it's
416    // not getting a unique value.
417
418    tc->setIntReg(SyscallPseudoReturnReg, 99); //PID
419    return 100;
420}
421
422SyscallReturn
423getppidFunc(SyscallDesc *desc, int callnum, Process *process,
424           ThreadContext *tc)
425{
426    return 99;
427}
428
429SyscallReturn
430getuidFunc(SyscallDesc *desc, int callnum, Process *process,
431           ThreadContext *tc)
432{
433    return 100;		// UID
434}
435
436SyscallReturn
437geteuidFunc(SyscallDesc *desc, int callnum, Process *process,
438           ThreadContext *tc)
439{
440    return 100;		// UID
441}
442
443SyscallReturn
444getgidFunc(SyscallDesc *desc, int callnum, Process *process,
445           ThreadContext *tc)
446{
447    return 100;
448}
449
450SyscallReturn
451getegidFunc(SyscallDesc *desc, int callnum, Process *process,
452           ThreadContext *tc)
453{
454    return 100;
455}
456
457
458