1 //===-- sanitizer_posix_libcdep.cpp ---------------------------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file is shared between AddressSanitizer and ThreadSanitizer
10 // run-time libraries and implements libc-dependent POSIX-specific functions
11 // from sanitizer_libc.h.
12 //===----------------------------------------------------------------------===//
14 #include "sanitizer_platform.h"
18 #include "sanitizer_common.h"
19 #include "sanitizer_flags.h"
20 #include "sanitizer_platform_limits_netbsd.h"
21 #include "sanitizer_platform_limits_openbsd.h"
22 #include "sanitizer_platform_limits_posix.h"
23 #include "sanitizer_platform_limits_solaris.h"
24 #include "sanitizer_posix.h"
25 #include "sanitizer_procmaps.h"
33 #include <sys/resource.h>
36 #include <sys/types.h>
41 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
42 // that, it was never implemented. So just define it to zero.
44 #define MAP_NORESERVE 0
47 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
49 namespace __sanitizer {
55 uptr GetThreadSelf() {
56 return (uptr)pthread_self();
59 void ReleaseMemoryPagesToOS(uptr beg, uptr end) {
60 uptr page_size = GetPageSizeCached();
61 uptr beg_aligned = RoundUpTo(beg, page_size);
62 uptr end_aligned = RoundDownTo(end, page_size);
63 if (beg_aligned < end_aligned)
64 // In the default Solaris compilation environment, madvise() is declared
65 // to take a caddr_t arg; casting it to void * results in an invalid
66 // conversion error, so use char * instead.
67 madvise((char *)beg_aligned, end_aligned - beg_aligned,
68 SANITIZER_MADVISE_DONTNEED);
71 void SetShadowRegionHugePageMode(uptr addr, uptr size) {
72 #ifdef MADV_NOHUGEPAGE // May not be defined on old systems.
73 if (common_flags()->no_huge_pages_for_shadow)
74 madvise((char *)addr, size, MADV_NOHUGEPAGE);
76 madvise((char *)addr, size, MADV_HUGEPAGE);
77 #endif // MADV_NOHUGEPAGE
80 bool DontDumpShadowMemory(uptr addr, uptr length) {
81 #if defined(MADV_DONTDUMP)
82 return madvise((char *)addr, length, MADV_DONTDUMP) == 0;
83 #elif defined(MADV_NOCORE)
84 return madvise((char *)addr, length, MADV_NOCORE) == 0;
87 #endif // MADV_DONTDUMP
90 static rlim_t getlim(int res) {
92 CHECK_EQ(0, getrlimit(res, &rlim));
96 static void setlim(int res, rlim_t lim) {
98 if (getrlimit(res, const_cast<struct rlimit *>(&rlim))) {
99 Report("ERROR: %s getrlimit() failed %d\n", SanitizerToolName, errno);
103 if (setrlimit(res, const_cast<struct rlimit *>(&rlim))) {
104 Report("ERROR: %s setrlimit() failed %d\n", SanitizerToolName, errno);
109 void DisableCoreDumperIfNecessary() {
110 if (common_flags()->disable_coredump) {
111 setlim(RLIMIT_CORE, 0);
115 bool StackSizeIsUnlimited() {
116 rlim_t stack_size = getlim(RLIMIT_STACK);
117 return (stack_size == RLIM_INFINITY);
120 void SetStackSizeLimitInBytes(uptr limit) {
121 setlim(RLIMIT_STACK, (rlim_t)limit);
122 CHECK(!StackSizeIsUnlimited());
125 bool AddressSpaceIsUnlimited() {
126 rlim_t as_size = getlim(RLIMIT_AS);
127 return (as_size == RLIM_INFINITY);
130 void SetAddressSpaceUnlimited() {
131 setlim(RLIMIT_AS, RLIM_INFINITY);
132 CHECK(AddressSpaceIsUnlimited());
135 void SleepForSeconds(int seconds) {
139 void SleepForMillis(int millis) {
140 usleep(millis * 1000);
145 // If we are handling SIGABRT, unhandle it first.
146 // TODO(vitalybuka): Check if handler belongs to sanitizer.
147 if (GetHandleSignalMode(SIGABRT) != kHandleSignalNo) {
148 struct sigaction sigact;
149 internal_memset(&sigact, 0, sizeof(sigact));
150 sigact.sa_sigaction = (sa_sigaction_t)SIG_DFL;
151 internal_sigaction(SIGABRT, &sigact, nullptr);
158 int Atexit(void (*function)(void)) {
160 return atexit(function);
166 bool SupportsColoredOutput(fd_t fd) {
167 return isatty(fd) != 0;
171 // TODO(glider): different tools may require different altstack size.
172 static const uptr kAltStackSize = SIGSTKSZ * 4; // SIGSTKSZ is not enough.
174 void SetAlternateSignalStack() {
175 stack_t altstack, oldstack;
176 CHECK_EQ(0, sigaltstack(nullptr, &oldstack));
177 // If the alternate stack is already in place, do nothing.
178 // Android always sets an alternate stack, but it's too small for us.
179 if (!SANITIZER_ANDROID && !(oldstack.ss_flags & SS_DISABLE)) return;
180 // TODO(glider): the mapped stack should have the MAP_STACK flag in the
181 // future. It is not required by man 2 sigaltstack now (they're using
183 void* base = MmapOrDie(kAltStackSize, __func__);
184 altstack.ss_sp = (char*) base;
185 altstack.ss_flags = 0;
186 altstack.ss_size = kAltStackSize;
187 CHECK_EQ(0, sigaltstack(&altstack, nullptr));
190 void UnsetAlternateSignalStack() {
191 stack_t altstack, oldstack;
192 altstack.ss_sp = nullptr;
193 altstack.ss_flags = SS_DISABLE;
194 altstack.ss_size = kAltStackSize; // Some sane value required on Darwin.
195 CHECK_EQ(0, sigaltstack(&altstack, &oldstack));
196 UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
199 static void MaybeInstallSigaction(int signum,
200 SignalHandlerType handler) {
201 if (GetHandleSignalMode(signum) == kHandleSignalNo) return;
203 struct sigaction sigact;
204 internal_memset(&sigact, 0, sizeof(sigact));
205 sigact.sa_sigaction = (sa_sigaction_t)handler;
206 // Do not block the signal from being received in that signal's handler.
207 // Clients are responsible for handling this correctly.
208 sigact.sa_flags = SA_SIGINFO | SA_NODEFER;
209 if (common_flags()->use_sigaltstack) sigact.sa_flags |= SA_ONSTACK;
210 CHECK_EQ(0, internal_sigaction(signum, &sigact, nullptr));
211 VReport(1, "Installed the sigaction for signal %d\n", signum);
214 void InstallDeadlySignalHandlers(SignalHandlerType handler) {
215 // Set the alternate signal stack for the main thread.
216 // This will cause SetAlternateSignalStack to be called twice, but the stack
217 // will be actually set only once.
218 if (common_flags()->use_sigaltstack) SetAlternateSignalStack();
219 MaybeInstallSigaction(SIGSEGV, handler);
220 MaybeInstallSigaction(SIGBUS, handler);
221 MaybeInstallSigaction(SIGABRT, handler);
222 MaybeInstallSigaction(SIGFPE, handler);
223 MaybeInstallSigaction(SIGILL, handler);
224 MaybeInstallSigaction(SIGTRAP, handler);
227 bool SignalContext::IsStackOverflow() const {
228 // Access at a reasonable offset above SP, or slightly below it (to account
229 // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
230 // probably a stack overflow.
232 // On s390, the fault address in siginfo points to start of the page, not
233 // to the precise word that was accessed. Mask off the low bits of sp to
234 // take it into account.
235 bool IsStackAccess = addr >= (sp & ~0xFFF) && addr < sp + 0xFFFF;
237 // Let's accept up to a page size away from top of stack. Things like stack
238 // probing can trigger accesses with such large offsets.
239 bool IsStackAccess = addr + GetPageSizeCached() > sp && addr < sp + 0xFFFF;
243 // Large stack frames can be allocated with e.g.
245 // stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
246 // If the store faults then sp will not have been updated, so test above
247 // will not work, because the fault address will be more than just "slightly"
249 if (!IsStackAccess && IsAccessibleMemoryRange(pc, 4)) {
250 u32 inst = *(unsigned *)pc;
251 u32 ra = (inst >> 16) & 0x1F;
252 u32 opcd = inst >> 26;
253 u32 xo = (inst >> 1) & 0x3FF;
254 // Check for store-with-update to sp. The instructions we accept are:
255 // stbu rs,d(ra) stbux rs,ra,rb
256 // sthu rs,d(ra) sthux rs,ra,rb
257 // stwu rs,d(ra) stwux rs,ra,rb
258 // stdu rs,ds(ra) stdux rs,ra,rb
259 // where ra is r1 (the stack pointer).
261 (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
262 (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
263 IsStackAccess = true;
265 #endif // __powerpc__
267 // We also check si_code to filter out SEGV caused by something else other
268 // then hitting the guard page or unmapped memory, like, for example,
269 // unaligned memory access.
270 auto si = static_cast<const siginfo_t *>(siginfo);
271 return IsStackAccess &&
272 (si->si_code == si_SEGV_MAPERR || si->si_code == si_SEGV_ACCERR);
275 #endif // SANITIZER_GO
277 bool IsAccessibleMemoryRange(uptr beg, uptr size) {
278 uptr page_size = GetPageSizeCached();
279 // Checking too large memory ranges is slow.
280 CHECK_LT(size, page_size * 10);
285 internal_write(sock_pair[1], reinterpret_cast<void *>(beg), size);
288 if (internal_iserror(bytes_written, &write_errno)) {
289 CHECK_EQ(EFAULT, write_errno);
292 result = (bytes_written == size);
294 internal_close(sock_pair[0]);
295 internal_close(sock_pair[1]);
299 void PlatformPrepareForSandboxing(__sanitizer_sandbox_arguments *args) {
300 // Some kinds of sandboxes may forbid filesystem access, so we won't be able
301 // to read the file mappings from /proc/self/maps. Luckily, neither the
302 // process will be able to load additional libraries, so it's fine to use the
304 MemoryMappingLayout::CacheMemoryMappings();
307 static bool MmapFixed(uptr fixed_addr, uptr size, int additional_flags,
309 size = RoundUpTo(size, GetPageSizeCached());
310 fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
312 MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
313 MAP_PRIVATE | MAP_FIXED | additional_flags | MAP_ANON, name);
315 if (internal_iserror(p, &reserrno)) {
316 Report("ERROR: %s failed to "
317 "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
318 SanitizerToolName, size, size, fixed_addr, reserrno);
321 IncreaseTotalMmap(size);
325 bool MmapFixedNoReserve(uptr fixed_addr, uptr size, const char *name) {
326 return MmapFixed(fixed_addr, size, MAP_NORESERVE, name);
329 bool MmapFixedSuperNoReserve(uptr fixed_addr, uptr size, const char *name) {
330 #if SANITIZER_FREEBSD
331 if (common_flags()->no_huge_pages_for_shadow)
332 return MmapFixedNoReserve(fixed_addr, size, name);
333 // MAP_NORESERVE is implicit with FreeBSD
334 return MmapFixed(fixed_addr, size, MAP_ALIGNED_SUPER, name);
336 bool r = MmapFixedNoReserve(fixed_addr, size, name);
338 SetShadowRegionHugePageMode(fixed_addr, size);
343 uptr ReservedAddressRange::Init(uptr size, const char *name, uptr fixed_addr) {
344 base_ = fixed_addr ? MmapFixedNoAccess(fixed_addr, size, name)
345 : MmapNoAccess(size);
348 (void)os_handle_; // unsupported
349 return reinterpret_cast<uptr>(base_);
352 // Uses fixed_addr for now.
353 // Will use offset instead once we've implemented this function for real.
354 uptr ReservedAddressRange::Map(uptr fixed_addr, uptr size, const char *name) {
355 return reinterpret_cast<uptr>(
356 MmapFixedOrDieOnFatalError(fixed_addr, size, name));
359 uptr ReservedAddressRange::MapOrDie(uptr fixed_addr, uptr size,
361 return reinterpret_cast<uptr>(MmapFixedOrDie(fixed_addr, size, name));
364 void ReservedAddressRange::Unmap(uptr addr, uptr size) {
365 CHECK_LE(size, size_);
366 if (addr == reinterpret_cast<uptr>(base_))
367 // If we unmap the whole range, just null out the base.
368 base_ = (size == size_) ? nullptr : reinterpret_cast<void*>(addr + size);
370 CHECK_EQ(addr + size, reinterpret_cast<uptr>(base_) + size_);
372 UnmapOrDie(reinterpret_cast<void*>(addr), size);
375 void *MmapFixedNoAccess(uptr fixed_addr, uptr size, const char *name) {
376 return (void *)MmapNamed((void *)fixed_addr, size, PROT_NONE,
377 MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE | MAP_ANON,
381 void *MmapNoAccess(uptr size) {
382 unsigned flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE;
383 return (void *)internal_mmap(nullptr, size, PROT_NONE, flags, -1, 0);
386 // This function is defined elsewhere if we intercepted pthread_attr_getstack.
388 SANITIZER_WEAK_ATTRIBUTE int
389 real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
392 int my_pthread_attr_getstack(void *attr, void **addr, uptr *size) {
393 #if !SANITIZER_GO && !SANITIZER_MAC
394 if (&real_pthread_attr_getstack)
395 return real_pthread_attr_getstack((pthread_attr_t *)attr, addr,
398 return pthread_attr_getstack((pthread_attr_t *)attr, addr, (size_t *)size);
402 void AdjustStackSize(void *attr_) {
403 pthread_attr_t *attr = (pthread_attr_t *)attr_;
406 my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
407 // GLibC will return (0 - stacksize) as the stack address in the case when
408 // stacksize is set, but stackaddr is not.
409 bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
410 // We place a lot of tool data into TLS, account for that.
411 const uptr minstacksize = GetTlsSize() + 128*1024;
412 if (stacksize < minstacksize) {
414 if (stacksize != 0) {
415 VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
417 pthread_attr_setstacksize(attr, minstacksize);
420 Printf("Sanitizer: pre-allocated stack size is insufficient: "
421 "%zu < %zu\n", stacksize, minstacksize);
422 Printf("Sanitizer: pthread_create is likely to fail.\n");
426 #endif // !SANITIZER_GO
428 pid_t StartSubprocess(const char *program, const char *const argv[],
429 fd_t stdin_fd, fd_t stdout_fd, fd_t stderr_fd) {
430 auto file_closer = at_scope_exit([&] {
431 if (stdin_fd != kInvalidFd) {
432 internal_close(stdin_fd);
434 if (stdout_fd != kInvalidFd) {
435 internal_close(stdout_fd);
437 if (stderr_fd != kInvalidFd) {
438 internal_close(stderr_fd);
442 int pid = internal_fork();
446 if (internal_iserror(pid, &rverrno)) {
447 Report("WARNING: failed to fork (errno %d)\n", rverrno);
454 if (stdin_fd != kInvalidFd) {
455 internal_close(STDIN_FILENO);
456 internal_dup2(stdin_fd, STDIN_FILENO);
457 internal_close(stdin_fd);
459 if (stdout_fd != kInvalidFd) {
460 internal_close(STDOUT_FILENO);
461 internal_dup2(stdout_fd, STDOUT_FILENO);
462 internal_close(stdout_fd);
464 if (stderr_fd != kInvalidFd) {
465 internal_close(STDERR_FILENO);
466 internal_dup2(stderr_fd, STDERR_FILENO);
467 internal_close(stderr_fd);
470 for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--) internal_close(fd);
472 execv(program, const_cast<char **>(&argv[0]));
479 bool IsProcessRunning(pid_t pid) {
481 uptr waitpid_status = internal_waitpid(pid, &process_status, WNOHANG);
483 if (internal_iserror(waitpid_status, &local_errno)) {
484 VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
487 return waitpid_status == 0;
490 int WaitForProcess(pid_t pid) {
492 uptr waitpid_status = internal_waitpid(pid, &process_status, 0);
494 if (internal_iserror(waitpid_status, &local_errno)) {
495 VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
498 return process_status;
501 bool IsStateDetached(int state) {
502 return state == PTHREAD_CREATE_DETACHED;
505 } // namespace __sanitizer
507 #endif // SANITIZER_POSIX