1/*
2 * Copyright (c) 2014-2016 Advanced Micro Devices, Inc.
3 * Copyright (c) 2012 ARM Limited
4 * All rights reserved
5 *
6 * The license below extends only to copyright in the software and shall
7 * not be construed as granting a license to any other intellectual
8 * property including but not limited to intellectual property relating
9 * to a hardware implementation of the functionality of the software
10 * licensed hereunder. You may use the software subject to the license
11 * terms below provided that you ensure that this notice is replicated
12 * unmodified and in its entirety in all distributions of the software,
13 * modified or unmodified, in source code or in binary form.
14 *
15 * Copyright (c) 2001-2005 The Regents of The University of Michigan
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Nathan Binkert
42 * Steve Reinhardt
43 * Ali Saidi
44 * Brandon Potter
45 */
46
47#include "sim/process.hh"
48
49#include <fcntl.h>
50#include <unistd.h>
51
52#include <array>
53#include <climits>
54#include <csignal>
55#include <map>
56#include <string>
57#include <vector>
58
59#include "base/intmath.hh"
60#include "base/loader/object_file.hh"
61#include "base/loader/symtab.hh"
62#include "base/statistics.hh"
63#include "config/the_isa.hh"
64#include "cpu/thread_context.hh"
65#include "mem/page_table.hh"
66#include "mem/se_translating_port_proxy.hh"
67#include "params/Process.hh"
68#include "sim/emul_driver.hh"
69#include "sim/fd_array.hh"
70#include "sim/fd_entry.hh"
71#include "sim/redirect_path.hh"
72#include "sim/syscall_desc.hh"
73#include "sim/system.hh"
74
75using namespace std;
76using namespace TheISA;
77
78static std::string
79normalize(std::string& directory)
80{
81 if (directory.back() != '/')
82 directory += '/';
83 return directory;
84}
85
86Process::Process(ProcessParams *params, EmulationPageTable *pTable,
87 ObjectFile *obj_file)
88 : SimObject(params), system(params->system),
89 useArchPT(params->useArchPT),
90 kvmInSE(params->kvmInSE),
91 useForClone(false),
92 pTable(pTable),
93 initVirtMem(system->getSystemPort(), this,
94 SETranslatingPortProxy::Always),
95 objFile(obj_file),
96 argv(params->cmd), envp(params->env),
97 executable(params->executable),
98 tgtCwd(normalize(params->cwd)),
99 hostCwd(checkPathRedirect(tgtCwd)),
100 release(params->release),
101 _uid(params->uid), _euid(params->euid),
102 _gid(params->gid), _egid(params->egid),
103 _pid(params->pid), _ppid(params->ppid),
104 _pgid(params->pgid), drivers(params->drivers),
105 fds(make_shared<FDArray>(params->input, params->output, params->errout)),
106 childClearTID(0)
107{
108 if (_pid >= System::maxPID)
109 fatal("_pid is too large: %d", _pid);
110
111 auto ret_pair = system->PIDs.emplace(_pid);
112 if (!ret_pair.second)
113 fatal("_pid %d is already used", _pid);
114
115 /**
116 * Linux bundles together processes into this concept called a thread
117 * group. The thread group is responsible for recording which processes
118 * behave as threads within a process context. The thread group leader
119 * is the process who's tgid is equal to its pid. Other processes which
120 * belong to the thread group, but do not lead the thread group, are
121 * treated as child threads. These threads are created by the clone system
122 * call with options specified to create threads (differing from the
123 * options used to implement a fork). By default, set up the tgid/pid
124 * with a new, equivalent value. If CLONE_THREAD is specified, patch
125 * the tgid value with the old process' value.
126 */
127 _tgid = params->pid;
128
129 exitGroup = new bool();
130 sigchld = new bool();
131
132 if (!debugSymbolTable) {
133 debugSymbolTable = new SymbolTable();
134 if (!objFile->loadGlobalSymbols(debugSymbolTable) ||
135 !objFile->loadLocalSymbols(debugSymbolTable) ||
136 !objFile->loadWeakSymbols(debugSymbolTable)) {
137 delete debugSymbolTable;
138 debugSymbolTable = nullptr;
139 }
140 }
141}
142
143void
144Process::clone(ThreadContext *otc, ThreadContext *ntc,
145 Process *np, RegVal flags)
146{
147#ifndef CLONE_VM
148#define CLONE_VM 0
149#endif
150#ifndef CLONE_FILES
151#define CLONE_FILES 0
152#endif
153#ifndef CLONE_THREAD
154#define CLONE_THREAD 0
155#endif
156 if (CLONE_VM & flags) {
157 /**
158 * Share the process memory address space between the new process
159 * and the old process. Changes in one will be visible in the other
160 * due to the pointer use.
161 */
162 delete np->pTable;
163 np->pTable = pTable;
164 ntc->getMemProxy().setPageTable(np->pTable);
164 auto &proxy = dynamic_cast<SETranslatingPortProxy &>(
165 ntc->getMemProxy());
166 proxy.setPageTable(np->pTable);
167
168 np->memState = memState;
169 } else {
170 /**
171 * Duplicate the process memory address space. The state needs to be
172 * copied over (rather than using pointers to share everything).
173 */
174 typedef std::vector<pair<Addr,Addr>> MapVec;
175 MapVec mappings;
176 pTable->getMappings(&mappings);
177
178 for (auto map : mappings) {
179 Addr paddr, vaddr = map.first;
180 bool alloc_page = !(np->pTable->translate(vaddr, paddr));
181 np->replicatePage(vaddr, paddr, otc, ntc, alloc_page);
182 }
183
184 *np->memState = *memState;
185 }
186
187 if (CLONE_FILES & flags) {
188 /**
189 * The parent and child file descriptors are shared because the
190 * two FDArray pointers are pointing to the same FDArray. Opening
191 * and closing file descriptors will be visible to both processes.
192 */
193 np->fds = fds;
194 } else {
195 /**
196 * Copy the file descriptors from the old process into the new
197 * child process. The file descriptors entry can be opened and
198 * closed independently of the other process being considered. The
199 * host file descriptors are also dup'd so that the flags for the
200 * host file descriptor is independent of the other process.
201 */
202 for (int tgt_fd = 0; tgt_fd < fds->getSize(); tgt_fd++) {
203 std::shared_ptr<FDArray> nfds = np->fds;
204 std::shared_ptr<FDEntry> this_fde = (*fds)[tgt_fd];
205 if (!this_fde) {
206 nfds->setFDEntry(tgt_fd, nullptr);
207 continue;
208 }
209 nfds->setFDEntry(tgt_fd, this_fde->clone());
210
211 auto this_hbfd = std::dynamic_pointer_cast<HBFDEntry>(this_fde);
212 if (!this_hbfd)
213 continue;
214
215 int this_sim_fd = this_hbfd->getSimFD();
216 if (this_sim_fd <= 2)
217 continue;
218
219 int np_sim_fd = dup(this_sim_fd);
220 assert(np_sim_fd != -1);
221
222 auto nhbfd = std::dynamic_pointer_cast<HBFDEntry>((*nfds)[tgt_fd]);
223 nhbfd->setSimFD(np_sim_fd);
224 }
225 }
226
227 if (CLONE_THREAD & flags) {
228 np->_tgid = _tgid;
229 delete np->exitGroup;
230 np->exitGroup = exitGroup;
231 }
232
233 np->argv.insert(np->argv.end(), argv.begin(), argv.end());
234 np->envp.insert(np->envp.end(), envp.begin(), envp.end());
235}
236
237void
238Process::regStats()
239{
240 SimObject::regStats();
241
242 using namespace Stats;
243
244 numSyscalls
245 .name(name() + ".numSyscalls")
246 .desc("Number of system calls")
247 ;
248}
249
250ThreadContext *
251Process::findFreeContext()
252{
253 for (auto &it : system->threadContexts) {
254 if (ThreadContext::Halted == it->status())
255 return it;
256 }
257 return nullptr;
258}
259
260void
261Process::revokeThreadContext(int context_id)
262{
263 std::vector<ContextID>::iterator it;
264 for (it = contextIds.begin(); it != contextIds.end(); it++) {
265 if (*it == context_id) {
266 contextIds.erase(it);
267 return;
268 }
269 }
270 warn("Unable to find thread context to revoke");
271}
272
273void
274Process::initState()
275{
276 if (contextIds.empty())
277 fatal("Process %s is not associated with any HW contexts!\n", name());
278
279 // first thread context for this process... initialize & enable
280 ThreadContext *tc = system->getThreadContext(contextIds[0]);
281
282 // mark this context as active so it will start ticking.
283 tc->activate();
284
285 pTable->initState(tc);
286}
287
288DrainState
289Process::drain()
290{
291 fds->updateFileOffsets();
292 return DrainState::Drained;
293}
294
295void
296Process::allocateMem(Addr vaddr, int64_t size, bool clobber)
297{
298 int npages = divCeil(size, (int64_t)PageBytes);
299 Addr paddr = system->allocPhysPages(npages);
300 pTable->map(vaddr, paddr, size,
301 clobber ? EmulationPageTable::Clobber :
302 EmulationPageTable::MappingFlags(0));
303}
304
305void
306Process::replicatePage(Addr vaddr, Addr new_paddr, ThreadContext *old_tc,
307 ThreadContext *new_tc, bool allocate_page)
308{
309 if (allocate_page)
310 new_paddr = system->allocPhysPages(1);
311
312 // Read from old physical page.
313 uint8_t *buf_p = new uint8_t[PageBytes];
314 old_tc->getMemProxy().readBlob(vaddr, buf_p, PageBytes);
315
316 // Create new mapping in process address space by clobbering existing
317 // mapping (if any existed) and then write to the new physical page.
318 bool clobber = true;
319 pTable->map(vaddr, new_paddr, PageBytes, clobber);
320 new_tc->getMemProxy().writeBlob(vaddr, buf_p, PageBytes);
321 delete[] buf_p;
322}
323
324bool
325Process::fixupStackFault(Addr vaddr)
326{
327 Addr stack_min = memState->getStackMin();
328 Addr stack_base = memState->getStackBase();
329 Addr max_stack_size = memState->getMaxStackSize();
330
331 // Check if this is already on the stack and there's just no page there
332 // yet.
333 if (vaddr >= stack_min && vaddr < stack_base) {
334 allocateMem(roundDown(vaddr, PageBytes), PageBytes);
335 return true;
336 }
337
338 // We've accessed the next page of the stack, so extend it to include
339 // this address.
340 if (vaddr < stack_min && vaddr >= stack_base - max_stack_size) {
341 while (vaddr < stack_min) {
342 stack_min -= TheISA::PageBytes;
343 if (stack_base - stack_min > max_stack_size)
344 fatal("Maximum stack size exceeded\n");
345 allocateMem(stack_min, TheISA::PageBytes);
346 inform("Increasing stack size by one page.");
347 }
348 memState->setStackMin(stack_min);
349 return true;
350 }
351 return false;
352}
353
354void
355Process::serialize(CheckpointOut &cp) const
356{
357 memState->serialize(cp);
358 pTable->serialize(cp);
359 /**
360 * Checkpoints for file descriptors currently do not work. Need to
361 * come back and fix them at a later date.
362 */
363
364 warn("Checkpoints for file descriptors currently do not work.");
365}
366
367void
368Process::unserialize(CheckpointIn &cp)
369{
370 memState->unserialize(cp);
371 pTable->unserialize(cp);
372 /**
373 * Checkpoints for file descriptors currently do not work. Need to
374 * come back and fix them at a later date.
375 */
376 warn("Checkpoints for file descriptors currently do not work.");
377 // The above returns a bool so that you could do something if you don't
378 // find the param in the checkpoint if you wanted to, like set a default
379 // but in this case we'll just stick with the instantiated value if not
380 // found.
381}
382
383bool
384Process::map(Addr vaddr, Addr paddr, int size, bool cacheable)
385{
386 pTable->map(vaddr, paddr, size,
387 cacheable ? EmulationPageTable::MappingFlags(0) :
388 EmulationPageTable::Uncacheable);
389 return true;
390}
391
392void
393Process::syscall(int64_t callnum, ThreadContext *tc, Fault *fault)
394{
395 numSyscalls++;
396
397 SyscallDesc *desc = getDesc(callnum);
398 if (desc == nullptr)
399 fatal("Syscall %d out of range", callnum);
400
401 desc->doSyscall(callnum, tc, fault);
402}
403
404RegVal
405Process::getSyscallArg(ThreadContext *tc, int &i, int width)
406{
407 return getSyscallArg(tc, i);
408}
409
410EmulatedDriver *
411Process::findDriver(std::string filename)
412{
413 for (EmulatedDriver *d : drivers) {
414 if (d->match(filename))
415 return d;
416 }
417
418 return nullptr;
419}
420
421std::string
422Process::checkPathRedirect(const std::string &filename)
423{
424 // If the input parameter contains a relative path, convert it.
425 // The target version of the current working directory is fine since
426 // we immediately convert it using redirect paths into a host version.
427 auto abs_path = absolutePath(filename, false);
428
429 for (auto path : system->redirectPaths) {
430 // Search through the redirect paths to see if a starting substring of
431 // our path falls into any buckets which need to redirected.
432 if (startswith(abs_path, path->appPath())) {
433 std::string tail = abs_path.substr(path->appPath().size());
434
435 // If this path needs to be redirected, search through a list
436 // of targets to see if we can match a valid file (or directory).
437 for (auto host_path : path->hostPaths()) {
438 if (access((host_path + tail).c_str(), R_OK) == 0) {
439 // Return the valid match.
440 return host_path + tail;
441 }
442 }
443 // The path needs to be redirected, but the file or directory
444 // does not exist on the host filesystem. Return the first
445 // host path as a default.
446 return path->hostPaths()[0] + tail;
447 }
448 }
449
450 // The path does not need to be redirected.
451 return abs_path;
452}
453
454void
455Process::updateBias()
456{
457 ObjectFile *interp = objFile->getInterpreter();
458
459 if (!interp || !interp->relocatable())
460 return;
461
462 // Determine how large the interpreters footprint will be in the process
463 // address space.
464 Addr interp_mapsize = roundUp(interp->mapSize(), TheISA::PageBytes);
465
466 // We are allocating the memory area; set the bias to the lowest address
467 // in the allocated memory region.
468 Addr mmap_end = memState->getMmapEnd();
469 Addr ld_bias = mmapGrowsDown() ? mmap_end - interp_mapsize : mmap_end;
470
471 // Adjust the process mmap area to give the interpreter room; the real
472 // execve system call would just invoke the kernel's internal mmap
473 // functions to make these adjustments.
474 mmap_end = mmapGrowsDown() ? ld_bias : mmap_end + interp_mapsize;
475 memState->setMmapEnd(mmap_end);
476
477 interp->updateBias(ld_bias);
478}
479
480ObjectFile *
481Process::getInterpreter()
482{
483 return objFile->getInterpreter();
484}
485
486Addr
487Process::getBias()
488{
489 ObjectFile *interp = getInterpreter();
490
491 return interp ? interp->bias() : objFile->bias();
492}
493
494Addr
495Process::getStartPC()
496{
497 ObjectFile *interp = getInterpreter();
498
499 return interp ? interp->entryPoint() : objFile->entryPoint();
500}
501
502std::string
503Process::absolutePath(const std::string &filename, bool host_filesystem)
504{
505 if (filename.empty() || startswith(filename, "/"))
506 return filename;
507
508 // Construct the absolute path given the current working directory for
509 // either the host filesystem or target filesystem. The distinction only
510 // matters if filesystem redirection is utilized in the simulation.
511 auto path_base = std::string();
512 if (host_filesystem) {
513 path_base = hostCwd;
514 assert(!hostCwd.empty());
515 } else {
516 path_base = tgtCwd;
517 assert(!tgtCwd.empty());
518 }
519
520 // Add a trailing '/' if the current working directory did not have one.
521 normalize(path_base);
522
523 // Append the filename onto the current working path.
524 auto absolute_path = path_base + filename;
525
526 return absolute_path;
527}
528
529Process *
530ProcessParams::create()
531{
532 Process *process = nullptr;
533
534 // If not specified, set the executable parameter equal to the
535 // simulated system's zeroth command line parameter
536 if (executable == "") {
537 executable = cmd[0];
538 }
539
540 ObjectFile *obj_file = createObjectFile(executable);
541 fatal_if(!obj_file, "Can't load object file %s", executable);
542
543 process = ObjectFile::tryLoaders(this, obj_file);
544 fatal_if(!process, "Unknown error creating process object.");
545
546 return process;
547}