sanitizer_posix.cc revision 7c9150579ed0278492f51cc8434b1d63a44b9bd1 
1//===-- sanitizer_posix.cc ------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is shared between AddressSanitizer and ThreadSanitizer
11// run-time libraries and implements POSIX-specific functions from
12// sanitizer_libc.h.
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_platform.h"
16#if SANITIZER_POSIX
17
18#include "sanitizer_common.h"
19#include "sanitizer_libc.h"
20#include "sanitizer_procmaps.h"
21#include "sanitizer_stacktrace.h"
22
23#include <fcntl.h>
24#include <signal.h>
25#include <sys/mman.h>
26
27#if SANITIZER_LINUX
28#include <sys/utsname.h>
29#endif
30
31#if SANITIZER_LINUX && !SANITIZER_ANDROID
32#include <sys/personality.h>
33#endif
34
35#if SANITIZER_FREEBSD
36// The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
37// that, it was never implemented.  So just define it to zero.
38#undef  MAP_NORESERVE
39#define MAP_NORESERVE 0
40#endif
41
42namespace __sanitizer {
43
44// ------------- sanitizer_common.h
45uptr GetMmapGranularity() {
46  return GetPageSize();
47}
48
49#if SANITIZER_WORDSIZE == 32
50// Take care of unusable kernel area in top gigabyte.
51static uptr GetKernelAreaSize() {
52#if SANITIZER_LINUX && !SANITIZER_X32
53  const uptr gbyte = 1UL << 30;
54
55  // Firstly check if there are writable segments
56  // mapped to top gigabyte (e.g. stack).
57  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
58  uptr end, prot;
59  while (proc_maps.Next(/*start*/0, &end,
60                        /*offset*/0, /*filename*/0,
61                        /*filename_size*/0, &prot)) {
62    if ((end >= 3 * gbyte)
63        && (prot & MemoryMappingLayout::kProtectionWrite) != 0)
64      return 0;
65  }
66
67#if !SANITIZER_ANDROID
68  // Even if nothing is mapped, top Gb may still be accessible
69  // if we are running on 64-bit kernel.
70  // Uname may report misleading results if personality type
71  // is modified (e.g. under schroot) so check this as well.
72  struct utsname uname_info;
73  int pers = personality(0xffffffffUL);
74  if (!(pers & PER_MASK)
75      && uname(&uname_info) == 0
76      && internal_strstr(uname_info.machine, "64"))
77    return 0;
78#endif  // SANITIZER_ANDROID
79
80  // Top gigabyte is reserved for kernel.
81  return gbyte;
82#else
83  return 0;
84#endif  // SANITIZER_LINUX && !SANITIZER_X32
85}
86#endif  // SANITIZER_WORDSIZE == 32
87
88uptr GetMaxVirtualAddress() {
89#if SANITIZER_WORDSIZE == 64
90# if defined(__powerpc64__) || defined(__aarch64__)
91  // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
92  // We somehow need to figure out which one we are using now and choose
93  // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
94  // Note that with 'ulimit -s unlimited' the stack is moved away from the top
95  // of the address space, so simply checking the stack address is not enough.
96  // This should (does) work for both PowerPC64 Endian modes.
97  // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
98  return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
99# elif defined(__mips64)
100  return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
101# else
102  return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
103# endif
104#else  // SANITIZER_WORDSIZE == 32
105  uptr res = (1ULL << 32) - 1;  // 0xffffffff;
106  if (!common_flags()->full_address_space)
107    res -= GetKernelAreaSize();
108  CHECK_LT(reinterpret_cast<uptr>(&res), res);
109  return res;
110#endif  // SANITIZER_WORDSIZE
111}
112
113void *MmapOrDie(uptr size, const char *mem_type) {
114  size = RoundUpTo(size, GetPageSizeCached());
115  uptr res = internal_mmap(0, size,
116                            PROT_READ | PROT_WRITE,
117                            MAP_PRIVATE | MAP_ANON, -1, 0);
118  int reserrno;
119  if (internal_iserror(res, &reserrno)) {
120    static int recursion_count;
121    if (recursion_count) {
122      // The Report() and CHECK calls below may call mmap recursively and fail.
123      // If we went into recursion, just die.
124      RawWrite("ERROR: Failed to mmap\n");
125      Die();
126    }
127    recursion_count++;
128    Report("ERROR: %s failed to "
129           "allocate 0x%zx (%zd) bytes of %s (errno: %d)\n",
130           SanitizerToolName, size, size, mem_type, reserrno);
131    DumpProcessMap();
132    CHECK("unable to mmap" && 0);
133  }
134  IncreaseTotalMmap(size);
135  return (void *)res;
136}
137
138void UnmapOrDie(void *addr, uptr size) {
139  if (!addr || !size) return;
140  uptr res = internal_munmap(addr, size);
141  if (internal_iserror(res)) {
142    Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
143           SanitizerToolName, size, size, addr);
144    CHECK("unable to unmap" && 0);
145  }
146  DecreaseTotalMmap(size);
147}
148
149void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
150  uptr PageSize = GetPageSizeCached();
151  uptr p = internal_mmap(0,
152      RoundUpTo(size, PageSize),
153      PROT_READ | PROT_WRITE,
154      MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
155      -1, 0);
156  int reserrno;
157  if (internal_iserror(p, &reserrno)) {
158    Report("ERROR: %s failed to "
159           "allocate noreserve 0x%zx (%zd) bytes for '%s' (errno: %d)\n",
160           SanitizerToolName, size, size, mem_type, reserrno);
161    CHECK("unable to mmap" && 0);
162  }
163  IncreaseTotalMmap(size);
164  return (void *)p;
165}
166
167void *MmapFixedNoReserve(uptr fixed_addr, uptr size) {
168  uptr PageSize = GetPageSizeCached();
169  uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
170      RoundUpTo(size, PageSize),
171      PROT_READ | PROT_WRITE,
172      MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
173      -1, 0);
174  int reserrno;
175  if (internal_iserror(p, &reserrno))
176    Report("ERROR: %s failed to "
177           "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
178           SanitizerToolName, size, size, fixed_addr, reserrno);
179  IncreaseTotalMmap(size);
180  return (void *)p;
181}
182
183void *MmapFixedOrDie(uptr fixed_addr, uptr size) {
184  uptr PageSize = GetPageSizeCached();
185  uptr p = internal_mmap((void*)(fixed_addr & ~(PageSize - 1)),
186      RoundUpTo(size, PageSize),
187      PROT_READ | PROT_WRITE,
188      MAP_PRIVATE | MAP_ANON | MAP_FIXED,
189      -1, 0);
190  int reserrno;
191  if (internal_iserror(p, &reserrno)) {
192    Report("ERROR: %s failed to "
193           "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
194           SanitizerToolName, size, size, fixed_addr, reserrno);
195    CHECK("unable to mmap" && 0);
196  }
197  IncreaseTotalMmap(size);
198  return (void *)p;
199}
200
201void *Mprotect(uptr fixed_addr, uptr size) {
202  return (void *)internal_mmap((void*)fixed_addr, size,
203                               PROT_NONE,
204                               MAP_PRIVATE | MAP_ANON | MAP_FIXED |
205                               MAP_NORESERVE, -1, 0);
206}
207
208uptr OpenFile(const char *filename, FileAccessMode mode) {
209  int flags;
210  switch (mode) {
211    case RdOnly: flags = O_RDONLY; break;
212    case WrOnly: flags = O_WRONLY | O_CREAT; break;
213    case RdWr: flags = O_RDWR | O_CREAT; break;
214  }
215  return internal_open(filename, flags, 0660);
216}
217
218void *MapFileToMemory(const char *file_name, uptr *buff_size) {
219  uptr openrv = OpenFile(file_name, RdOnly);
220  CHECK(!internal_iserror(openrv));
221  fd_t fd = openrv;
222  uptr fsize = internal_filesize(fd);
223  CHECK_NE(fsize, (uptr)-1);
224  CHECK_GT(fsize, 0);
225  *buff_size = RoundUpTo(fsize, GetPageSizeCached());
226  uptr map = internal_mmap(0, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
227  return internal_iserror(map) ? 0 : (void *)map;
228}
229
230void *MapWritableFileToMemory(void *addr, uptr size, uptr fd, uptr offset) {
231  uptr flags = MAP_SHARED;
232  if (addr) flags |= MAP_FIXED;
233  uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
234  int mmap_errno = 0;
235  if (internal_iserror(p, &mmap_errno)) {
236    Printf("could not map writable file (%zd, %zu, %zu): %zd, errno: %d\n",
237           fd, offset, size, p, mmap_errno);
238    return 0;
239  }
240  return (void *)p;
241}
242
243static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
244                                        uptr start2, uptr end2) {
245  CHECK(start1 <= end1);
246  CHECK(start2 <= end2);
247  return (end1 < start2) || (end2 < start1);
248}
249
250// FIXME: this is thread-unsafe, but should not cause problems most of the time.
251// When the shadow is mapped only a single thread usually exists (plus maybe
252// several worker threads on Mac, which aren't expected to map big chunks of
253// memory).
254bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
255  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
256  uptr start, end;
257  while (proc_maps.Next(&start, &end,
258                        /*offset*/0, /*filename*/0, /*filename_size*/0,
259                        /*protection*/0)) {
260    CHECK_NE(0, end);
261    if (!IntervalsAreSeparate(start, end - 1, range_start, range_end))
262      return false;
263  }
264  return true;
265}
266
267void DumpProcessMap() {
268  MemoryMappingLayout proc_maps(/*cache_enabled*/true);
269  uptr start, end;
270  const sptr kBufSize = 4095;
271  char *filename = (char*)MmapOrDie(kBufSize, __func__);
272  Report("Process memory map follows:\n");
273  while (proc_maps.Next(&start, &end, /* file_offset */0,
274                        filename, kBufSize, /* protection */0)) {
275    Printf("\t%p-%p\t%s\n", (void*)start, (void*)end, filename);
276  }
277  Report("End of process memory map.\n");
278  UnmapOrDie(filename, kBufSize);
279}
280
281const char *GetPwd() {
282  return GetEnv("PWD");
283}
284
285char *FindPathToBinary(const char *name) {
286  const char *path = GetEnv("PATH");
287  if (!path)
288    return 0;
289  uptr name_len = internal_strlen(name);
290  InternalScopedBuffer<char> buffer(kMaxPathLength);
291  const char *beg = path;
292  while (true) {
293    const char *end = internal_strchrnul(beg, ':');
294    uptr prefix_len = end - beg;
295    if (prefix_len + name_len + 2 <= kMaxPathLength) {
296      internal_memcpy(buffer.data(), beg, prefix_len);
297      buffer[prefix_len] = '/';
298      internal_memcpy(&buffer[prefix_len + 1], name, name_len);
299      buffer[prefix_len + 1 + name_len] = '\0';
300      if (FileExists(buffer.data()))
301        return internal_strdup(buffer.data());
302    }
303    if (*end == '\0') break;
304    beg = end + 1;
305  }
306  return 0;
307}
308
309bool IsPathSeparator(const char c) {
310  return c == '/';
311}
312
313bool IsAbsolutePath(const char *path) {
314  return path != nullptr && IsPathSeparator(path[0]);
315}
316
317void ReportFile::Write(const char *buffer, uptr length) {
318  SpinMutexLock l(mu);
319  static const char *kWriteError =
320      "ReportFile::Write() can't output requested buffer!\n";
321  ReopenIfNecessary();
322  if (length != internal_write(fd, buffer, length)) {
323    internal_write(fd, kWriteError, internal_strlen(kWriteError));
324    Die();
325  }
326}
327
328bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
329  uptr s, e, off, prot;
330  InternalScopedString buff(kMaxPathLength);
331  MemoryMappingLayout proc_maps(/*cache_enabled*/false);
332  while (proc_maps.Next(&s, &e, &off, buff.data(), buff.size(), &prot)) {
333    if ((prot & MemoryMappingLayout::kProtectionExecute) != 0
334        && internal_strcmp(module, buff.data()) == 0) {
335      *start = s;
336      *end = e;
337      return true;
338    }
339  }
340  return false;
341}
342
343SignalContext SignalContext::Create(void *siginfo, void *context) {
344  uptr addr = (uptr)((siginfo_t*)siginfo)->si_addr;
345  uptr pc, sp, bp;
346  GetPcSpBp(context, &pc, &sp, &bp);
347  return SignalContext(context, addr, pc, sp, bp);
348}
349
350}  // namespace __sanitizer
351
352#endif  // SANITIZER_POSIX
353