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1//===-- sanitizer_posix.cpp -----------------------------------------------===//
2//
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
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is shared between AddressSanitizer and ThreadSanitizer
10// run-time libraries and implements POSIX-specific functions from
11// sanitizer_posix.h.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_platform.h"
15
16#if SANITIZER_POSIX
17
18#include "sanitizer_common.h"
19#include "sanitizer_file.h"
20#include "sanitizer_flags.h"
21#include "sanitizer_libc.h"
22#include "sanitizer_posix.h"
23#include "sanitizer_procmaps.h"
24
25#include <errno.h>
26#include <fcntl.h>
27#include <signal.h>
28#include <sys/mman.h>
29
30#if SANITIZER_FREEBSD
31// The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
32// that, it was never implemented. So just define it to zero.
33#undef MAP_NORESERVE
34#define MAP_NORESERVE 0
35#endif
36
37namespace __sanitizer {
38
39// ------------- sanitizer_common.h
40uptr GetMmapGranularity() {
41 return GetPageSize();
42}
43
44bool ErrorIsOOM(error_t err) { return err == ENOMEM; }
45
46void *MmapOrDie(uptr size, const char *mem_type, bool raw_report) {
47 size = RoundUpTo(size, GetPageSizeCached());
48 uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
49 MAP_PRIVATE | MAP_ANON, mem_type);
50 int reserrno;
51 if (UNLIKELY(internal_iserror(res, &reserrno)))
52 ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno, raw_report);
53 IncreaseTotalMmap(size);
54 return (void *)res;
55}
56
57void UnmapOrDie(void *addr, uptr size, bool raw_report) {
58 if (!addr || !size) return;
59 uptr res = internal_munmap(addr, size);
60 int reserrno;
61 if (UNLIKELY(internal_iserror(res, &reserrno)))
62 ReportMunmapFailureAndDie(addr, size, reserrno, raw_report);
63 DecreaseTotalMmap(size);
64}
65
66void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
67 size = RoundUpTo(size, GetPageSizeCached());
68 uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
69 MAP_PRIVATE | MAP_ANON, mem_type);
70 int reserrno;
71 if (UNLIKELY(internal_iserror(res, &reserrno))) {
72 if (reserrno == ENOMEM)
73 return nullptr;
74 ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
75 }
76 IncreaseTotalMmap(size);
77 return (void *)res;
78}
79
80// We want to map a chunk of address space aligned to 'alignment'.
81// We do it by mapping a bit more and then unmapping redundant pieces.
82// We probably can do it with fewer syscalls in some OS-dependent way.
83void *MmapAlignedOrDieOnFatalError(uptr size, uptr alignment,
84 const char *mem_type) {
85 CHECK(IsPowerOfTwo(size));
86 CHECK(IsPowerOfTwo(alignment));
87 uptr map_size = size + alignment;
88 // mmap maps entire pages and rounds up map_size needs to be a an integral
89 // number of pages.
90 // We need to be aware of this size for calculating end and for unmapping
91 // fragments before and after the alignment region.
92 map_size = RoundUpTo(map_size, GetPageSizeCached());
93 uptr map_res = (uptr)MmapOrDieOnFatalError(map_size, mem_type);
94 if (UNLIKELY(!map_res))
95 return nullptr;
96 uptr res = map_res;
97 if (!IsAligned(res, alignment)) {
98 res = (map_res + alignment - 1) & ~(alignment - 1);
99 UnmapOrDie((void*)map_res, res - map_res);
100 }
101 uptr map_end = map_res + map_size;
102 uptr end = res + size;
103 end = RoundUpTo(end, GetPageSizeCached());
104 if (end != map_end) {
105 CHECK_LT(end, map_end);
106 UnmapOrDie((void*)end, map_end - end);
107 }
108 return (void*)res;
109}
110
111void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
112 size = RoundUpTo(size, GetPageSizeCached());
113 uptr p = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
114 MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, mem_type);
115 int reserrno;
116 if (UNLIKELY(internal_iserror(p, &reserrno)))
117 ReportMmapFailureAndDie(size, mem_type, "allocate noreserve", reserrno);
118 IncreaseTotalMmap(size);
119 return (void *)p;
120}
121
122static void *MmapFixedImpl(uptr fixed_addr, uptr size, bool tolerate_enomem,
123 const char *name) {
124 size = RoundUpTo(size, GetPageSizeCached());
125 fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
126 uptr p = MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
127 MAP_PRIVATE | MAP_ANON | MAP_FIXED, name);
128 int reserrno;
129 if (UNLIKELY(internal_iserror(p, &reserrno))) {
130 if (tolerate_enomem && reserrno == ENOMEM)
131 return nullptr;
132 char mem_type[40];
133 internal_snprintf(mem_type, sizeof(mem_type), "memory at address %p",
134 (void *)fixed_addr);
135 ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
136 }
137 IncreaseTotalMmap(size);
138 return (void *)p;
139}
140
141void *MmapFixedOrDie(uptr fixed_addr, uptr size, const char *name) {
142 return MmapFixedImpl(fixed_addr, size, false /*tolerate_enomem*/, name);
143}
144
145void *MmapFixedOrDieOnFatalError(uptr fixed_addr, uptr size, const char *name) {
146 return MmapFixedImpl(fixed_addr, size, true /*tolerate_enomem*/, name);
147}
148
149bool MprotectNoAccess(uptr addr, uptr size) {
150 return 0 == internal_mprotect((void*)addr, size, PROT_NONE);
151}
152
153bool MprotectReadOnly(uptr addr, uptr size) {
154 return 0 == internal_mprotect((void *)addr, size, PROT_READ);
155}
156
157bool MprotectReadWrite(uptr addr, uptr size) {
158 return 0 == internal_mprotect((void *)addr, size, PROT_READ | PROT_WRITE);
159}
160
161#if !SANITIZER_APPLE
162void MprotectMallocZones(void *addr, int prot) {}
163#endif
164
165fd_t OpenFile(const char *filename, FileAccessMode mode, error_t *errno_p) {
166 if (ShouldMockFailureToOpen(filename))
167 return kInvalidFd;
168 int flags;
169 switch (mode) {
170 case RdOnly: flags = O_RDONLY; break;
171 case WrOnly: flags = O_WRONLY | O_CREAT | O_TRUNC; break;
172 case RdWr: flags = O_RDWR | O_CREAT; break;
173 }
174 fd_t res = internal_open(filename, flags, 0660);
175 if (internal_iserror(res, errno_p))
176 return kInvalidFd;
177 return ReserveStandardFds(res);
178}
179
180void CloseFile(fd_t fd) {
181 internal_close(fd);
182}
183
184bool ReadFromFile(fd_t fd, void *buff, uptr buff_size, uptr *bytes_read,
185 error_t *error_p) {
186 uptr res = internal_read(fd, buff, buff_size);
187 if (internal_iserror(res, error_p))
188 return false;
189 if (bytes_read)
190 *bytes_read = res;
191 return true;
192}
193
194bool WriteToFile(fd_t fd, const void *buff, uptr buff_size, uptr *bytes_written,
195 error_t *error_p) {
196 uptr res = internal_write(fd, buff, buff_size);
197 if (internal_iserror(res, error_p))
198 return false;
199 if (bytes_written)
200 *bytes_written = res;
201 return true;
202}
203
204void *MapFileToMemory(const char *file_name, uptr *buff_size) {
205 fd_t fd = OpenFile(file_name, RdOnly);
206 CHECK(fd != kInvalidFd);
207 uptr fsize = internal_filesize(fd);
208 CHECK_NE(fsize, (uptr)-1);
209 CHECK_GT(fsize, 0);
210 *buff_size = RoundUpTo(fsize, GetPageSizeCached());
211 uptr map = internal_mmap(nullptr, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
212 return internal_iserror(map) ? nullptr : (void *)map;
213}
214
215void *MapWritableFileToMemory(void *addr, uptr size, fd_t fd, OFF_T offset) {
216 uptr flags = MAP_SHARED;
217 if (addr) flags |= MAP_FIXED;
218 uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
219 int mmap_errno = 0;
220 if (internal_iserror(p, &mmap_errno)) {
221 Printf("could not map writable file (%d, %lld, %zu): %zd, errno: %d\n",
222 fd, (long long)offset, size, p, mmap_errno);
223 return nullptr;
224 }
225 return (void *)p;
226}
227
228static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
229 uptr start2, uptr end2) {
230 CHECK(start1 <= end1);
231 CHECK(start2 <= end2);
232 return (end1 < start2) || (end2 < start1);
233}
234
235// FIXME: this is thread-unsafe, but should not cause problems most of the time.
236// When the shadow is mapped only a single thread usually exists (plus maybe
237// several worker threads on Mac, which aren't expected to map big chunks of
238// memory).
239bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
240 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
241 if (proc_maps.Error())
242 return true; // and hope for the best
243 MemoryMappedSegment segment;
244 while (proc_maps.Next(&segment)) {
245 if (segment.start == segment.end) continue; // Empty range.
246 CHECK_NE(0, segment.end);
247 if (!IntervalsAreSeparate(segment.start, segment.end - 1, range_start,
248 range_end))
249 return false;
250 }
251 return true;
252}
253
254#if !SANITIZER_APPLE
255void DumpProcessMap() {
256 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
257 const sptr kBufSize = 4095;
258 char *filename = (char*)MmapOrDie(kBufSize, __func__);
259 MemoryMappedSegment segment(filename, kBufSize);
260 Report("Process memory map follows:\n");
261 while (proc_maps.Next(&segment)) {
262 Printf("\t%p-%p\t%s\n", (void *)segment.start, (void *)segment.end,
263 segment.filename);
264 }
265 Report("End of process memory map.\n");
266 UnmapOrDie(filename, kBufSize);
267}
268#endif
269
270const char *GetPwd() {
271 return GetEnv("PWD");
272}
273
274bool IsPathSeparator(const char c) {
275 return c == '/';
276}
277
278bool IsAbsolutePath(const char *path) {
279 return path != nullptr && IsPathSeparator(path[0]);
280}
281
282void ReportFile::Write(const char *buffer, uptr length) {
283 SpinMutexLock l(mu);
284 ReopenIfNecessary();
285 internal_write(fd, buffer, length);
286}
287
288bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
289 MemoryMappingLayout proc_maps(/*cache_enabled*/false);
290 InternalMmapVector<char> buff(kMaxPathLength);
291 MemoryMappedSegment segment(buff.data(), buff.size());
292 while (proc_maps.Next(&segment)) {
293 if (segment.IsExecutable() &&
294 internal_strcmp(module, segment.filename) == 0) {
295 *start = segment.start;
296 *end = segment.end;
297 return true;
298 }
299 }
300 return false;
301}
302
303uptr SignalContext::GetAddress() const {
304 auto si = static_cast<const siginfo_t *>(siginfo);
305 return (uptr)si->si_addr;
306}
307
308bool SignalContext::IsMemoryAccess() const {
309 auto si = static_cast<const siginfo_t *>(siginfo);
310 return si->si_signo == SIGSEGV || si->si_signo == SIGBUS;
311}
312
313int SignalContext::GetType() const {
314 return static_cast<const siginfo_t *>(siginfo)->si_signo;
315}
316
317const char *SignalContext::Describe() const {
318 switch (GetType()) {
319 case SIGFPE:
320 return "FPE";
321 case SIGILL:
322 return "ILL";
323 case SIGABRT:
324 return "ABRT";
325 case SIGSEGV:
326 return "SEGV";
327 case SIGBUS:
328 return "BUS";
329 case SIGTRAP:
330 return "TRAP";
331 }
332 return "UNKNOWN SIGNAL";
333}
334
335fd_t ReserveStandardFds(fd_t fd) {
336 CHECK_GE(fd, 0);
337 if (fd > 2)
338 return fd;
339 bool used[3];
340 internal_memset(used, 0, sizeof(used));
341 while (fd <= 2) {
342 used[fd] = true;
343 fd = internal_dup(fd);
344 }
345 for (int i = 0; i <= 2; ++i)
346 if (used[i])
347 internal_close(i);
348 return fd;
349}
350
351bool ShouldMockFailureToOpen(const char *path) {
352 return common_flags()->test_only_emulate_no_memorymap &&
353 internal_strncmp(path, "/proc/", 6) == 0;
354}
355
356bool OpenReadsVaArgs(int oflag) {
357# ifdef O_TMPFILE
358 return (oflag & (O_CREAT | O_TMPFILE)) != 0;
359# else
360 return (oflag & O_CREAT) != 0;
361# endif
362}
363
364# if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_GO
365int GetNamedMappingFd(const char *name, uptr size, int *flags) {
366 if (!common_flags()->decorate_proc_maps || !name)
367 return -1;
368 char shmname[200];
369 CHECK(internal_strlen(name) < sizeof(shmname) - 10);
370 internal_snprintf(shmname, sizeof(shmname), "/dev/shm/%zu [%s]",
371 internal_getpid(), name);
372 int o_cloexec = 0;
373#if defined(O_CLOEXEC)
374 o_cloexec = O_CLOEXEC;
375#endif
376 int fd = ReserveStandardFds(
377 internal_open(shmname, O_RDWR | O_CREAT | O_TRUNC | o_cloexec, S_IRWXU));
378 CHECK_GE(fd, 0);
379 int res = internal_ftruncate(fd, size);
380#if !defined(O_CLOEXEC)
381 res = fcntl(fd, F_SETFD, FD_CLOEXEC);
382 CHECK_EQ(0, res);
383#endif
384 CHECK_EQ(0, res);
385 res = internal_unlink(shmname);
386 CHECK_EQ(0, res);
387 *flags &= ~(MAP_ANON | MAP_ANONYMOUS);
388 return fd;
389}
390#else
391int GetNamedMappingFd(const char *name, uptr size, int *flags) {
392 return -1;
393}
394#endif
395
396#if SANITIZER_ANDROID
397#define PR_SET_VMA 0x53564d41
398#define PR_SET_VMA_ANON_NAME 0
399void DecorateMapping(uptr addr, uptr size, const char *name) {
400 if (!common_flags()->decorate_proc_maps || !name)
401 return;
402 internal_prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, (uptr)name);
403}
404#else
405void DecorateMapping(uptr addr, uptr size, const char *name) {
406}
407#endif
408
409uptr MmapNamed(void *addr, uptr length, int prot, int flags, const char *name) {
410 int fd = GetNamedMappingFd(name, length, &flags);
411 uptr res = internal_mmap(addr, length, prot, flags, fd, 0);
412 if (!internal_iserror(res))
413 DecorateMapping(res, length, name);
414 return res;
415}
416
417
418} // namespace __sanitizer
419
420#endif // SANITIZER_POSIX