1 //===-- tsan_platform_linux.cc --------------------------------------------===//
2 //
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
5 //
6 //===----------------------------------------------------------------------===//
7 //
8 // This file is a part of ThreadSanitizer (TSan), a race detector.
9 //
10 // Linux- and FreeBSD-specific code.
11 //===----------------------------------------------------------------------===//
12
13
14 #include "sanitizer_common/sanitizer_platform.h"
15 #if SANITIZER_LINUX || SANITIZER_FREEBSD
16
17 #include "sanitizer_common/sanitizer_common.h"
18 #include "sanitizer_common/sanitizer_libc.h"
19 #include "sanitizer_common/sanitizer_posix.h"
20 #include "sanitizer_common/sanitizer_procmaps.h"
21 #include "sanitizer_common/sanitizer_stoptheworld.h"
22 #include "sanitizer_common/sanitizer_stackdepot.h"
23 #include "tsan_platform.h"
24 #include "tsan_rtl.h"
25 #include "tsan_flags.h"
26
27 #include <fcntl.h>
28 #include <pthread.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <stdarg.h>
34 #include <sys/mman.h>
35 #include <sys/syscall.h>
36 #include <sys/socket.h>
37 #include <sys/time.h>
38 #include <sys/types.h>
39 #include <sys/resource.h>
40 #include <sys/stat.h>
41 #include <unistd.h>
42 #include <errno.h>
43 #include <sched.h>
44 #include <dlfcn.h>
45 #if SANITIZER_LINUX
46 #define __need_res_state
47 #include <resolv.h>
48 #endif
49
50 #ifdef sa_handler
51 # undef sa_handler
52 #endif
53
54 #ifdef sa_sigaction
55 # undef sa_sigaction
56 #endif
57
58 #if SANITIZER_FREEBSD
59 extern "C" void *__libc_stack_end;
60 void *__libc_stack_end = 0;
61 #endif
62
63 #if SANITIZER_LINUX && defined(__aarch64__)
64 void InitializeGuardPtr() __attribute__((visibility("hidden")));
65 #endif
66
67 namespace __tsan {
68
69 static uptr g_data_start;
70 static uptr g_data_end;
71
72 enum {
73 MemTotal = 0,
74 MemShadow = 1,
75 MemMeta = 2,
76 MemFile = 3,
77 MemMmap = 4,
78 MemTrace = 5,
79 MemHeap = 6,
80 MemOther = 7,
81 MemCount = 8,
82 };
83
FillProfileCallback(uptr p,uptr rss,bool file,uptr * mem,uptr stats_size)84 void FillProfileCallback(uptr p, uptr rss, bool file,
85 uptr *mem, uptr stats_size) {
86 mem[MemTotal] += rss;
87 if (p >= kShadowBeg && p < kShadowEnd)
88 mem[MemShadow] += rss;
89 else if (p >= kMetaShadowBeg && p < kMetaShadowEnd)
90 mem[MemMeta] += rss;
91 #ifndef SANITIZER_GO
92 else if (p >= kHeapMemBeg && p < kHeapMemEnd)
93 mem[MemHeap] += rss;
94 else if (p >= kLoAppMemBeg && p < kLoAppMemEnd)
95 mem[file ? MemFile : MemMmap] += rss;
96 else if (p >= kHiAppMemBeg && p < kHiAppMemEnd)
97 mem[file ? MemFile : MemMmap] += rss;
98 #else
99 else if (p >= kAppMemBeg && p < kAppMemEnd)
100 mem[file ? MemFile : MemMmap] += rss;
101 #endif
102 else if (p >= kTraceMemBeg && p < kTraceMemEnd)
103 mem[MemTrace] += rss;
104 else
105 mem[MemOther] += rss;
106 }
107
WriteMemoryProfile(char * buf,uptr buf_size,uptr nthread,uptr nlive)108 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
109 uptr mem[MemCount] = {};
110 __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
111 StackDepotStats *stacks = StackDepotGetStats();
112 internal_snprintf(buf, buf_size,
113 "RSS %zd MB: shadow:%zd meta:%zd file:%zd mmap:%zd"
114 " trace:%zd heap:%zd other:%zd stacks=%zd[%zd] nthr=%zd/%zd\n",
115 mem[MemTotal] >> 20, mem[MemShadow] >> 20, mem[MemMeta] >> 20,
116 mem[MemFile] >> 20, mem[MemMmap] >> 20, mem[MemTrace] >> 20,
117 mem[MemHeap] >> 20, mem[MemOther] >> 20,
118 stacks->allocated >> 20, stacks->n_uniq_ids,
119 nlive, nthread);
120 }
121
122 #if SANITIZER_LINUX
FlushShadowMemoryCallback(const SuspendedThreadsList & suspended_threads_list,void * argument)123 void FlushShadowMemoryCallback(
124 const SuspendedThreadsList &suspended_threads_list,
125 void *argument) {
126 FlushUnneededShadowMemory(kShadowBeg, kShadowEnd - kShadowBeg);
127 }
128 #endif
129
FlushShadowMemory()130 void FlushShadowMemory() {
131 #if SANITIZER_LINUX
132 StopTheWorld(FlushShadowMemoryCallback, 0);
133 #endif
134 }
135
136 #ifndef SANITIZER_GO
137 // Mark shadow for .rodata sections with the special kShadowRodata marker.
138 // Accesses to .rodata can't race, so this saves time, memory and trace space.
MapRodata()139 static void MapRodata() {
140 // First create temp file.
141 const char *tmpdir = GetEnv("TMPDIR");
142 if (tmpdir == 0)
143 tmpdir = GetEnv("TEST_TMPDIR");
144 #ifdef P_tmpdir
145 if (tmpdir == 0)
146 tmpdir = P_tmpdir;
147 #endif
148 if (tmpdir == 0)
149 return;
150 char name[256];
151 internal_snprintf(name, sizeof(name), "%s/tsan.rodata.%d",
152 tmpdir, (int)internal_getpid());
153 uptr openrv = internal_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
154 if (internal_iserror(openrv))
155 return;
156 internal_unlink(name); // Unlink it now, so that we can reuse the buffer.
157 fd_t fd = openrv;
158 // Fill the file with kShadowRodata.
159 const uptr kMarkerSize = 512 * 1024 / sizeof(u64);
160 InternalScopedBuffer<u64> marker(kMarkerSize);
161 // volatile to prevent insertion of memset
162 for (volatile u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++)
163 *p = kShadowRodata;
164 internal_write(fd, marker.data(), marker.size());
165 // Map the file into memory.
166 uptr page = internal_mmap(0, GetPageSizeCached(), PROT_READ | PROT_WRITE,
167 MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
168 if (internal_iserror(page)) {
169 internal_close(fd);
170 return;
171 }
172 // Map the file into shadow of .rodata sections.
173 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
174 uptr start, end, offset, prot;
175 // Reusing the buffer 'name'.
176 while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name), &prot)) {
177 if (name[0] != 0 && name[0] != '['
178 && (prot & MemoryMappingLayout::kProtectionRead)
179 && (prot & MemoryMappingLayout::kProtectionExecute)
180 && !(prot & MemoryMappingLayout::kProtectionWrite)
181 && IsAppMem(start)) {
182 // Assume it's .rodata
183 char *shadow_start = (char*)MemToShadow(start);
184 char *shadow_end = (char*)MemToShadow(end);
185 for (char *p = shadow_start; p < shadow_end; p += marker.size()) {
186 internal_mmap(p, Min<uptr>(marker.size(), shadow_end - p),
187 PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0);
188 }
189 }
190 }
191 internal_close(fd);
192 }
193
InitializeShadowMemoryPlatform()194 void InitializeShadowMemoryPlatform() {
195 MapRodata();
196 }
197
InitDataSeg()198 static void InitDataSeg() {
199 MemoryMappingLayout proc_maps(true);
200 uptr start, end, offset;
201 char name[128];
202 #if SANITIZER_FREEBSD
203 // On FreeBSD BSS is usually the last block allocated within the
204 // low range and heap is the last block allocated within the range
205 // 0x800000000-0x8ffffffff.
206 while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
207 /*protection*/ 0)) {
208 DPrintf("%p-%p %p %s\n", start, end, offset, name);
209 if ((start & 0xffff00000000ULL) == 0 && (end & 0xffff00000000ULL) == 0 &&
210 name[0] == '\0') {
211 g_data_start = start;
212 g_data_end = end;
213 }
214 }
215 #else
216 bool prev_is_data = false;
217 while (proc_maps.Next(&start, &end, &offset, name, ARRAY_SIZE(name),
218 /*protection*/ 0)) {
219 DPrintf("%p-%p %p %s\n", start, end, offset, name);
220 bool is_data = offset != 0 && name[0] != 0;
221 // BSS may get merged with [heap] in /proc/self/maps. This is not very
222 // reliable.
223 bool is_bss = offset == 0 &&
224 (name[0] == 0 || internal_strcmp(name, "[heap]") == 0) && prev_is_data;
225 if (g_data_start == 0 && is_data)
226 g_data_start = start;
227 if (is_bss)
228 g_data_end = end;
229 prev_is_data = is_data;
230 }
231 #endif
232 DPrintf("guessed data_start=%p data_end=%p\n", g_data_start, g_data_end);
233 CHECK_LT(g_data_start, g_data_end);
234 CHECK_GE((uptr)&g_data_start, g_data_start);
235 CHECK_LT((uptr)&g_data_start, g_data_end);
236 }
237
238 #endif // #ifndef SANITIZER_GO
239
InitializePlatform()240 void InitializePlatform() {
241 DisableCoreDumperIfNecessary();
242
243 // Go maps shadow memory lazily and works fine with limited address space.
244 // Unlimited stack is not a problem as well, because the executable
245 // is not compiled with -pie.
246 if (kCppMode) {
247 bool reexec = false;
248 // TSan doesn't play well with unlimited stack size (as stack
249 // overlaps with shadow memory). If we detect unlimited stack size,
250 // we re-exec the program with limited stack size as a best effort.
251 if (StackSizeIsUnlimited()) {
252 const uptr kMaxStackSize = 32 * 1024 * 1024;
253 VReport(1, "Program is run with unlimited stack size, which wouldn't "
254 "work with ThreadSanitizer.\n"
255 "Re-execing with stack size limited to %zd bytes.\n",
256 kMaxStackSize);
257 SetStackSizeLimitInBytes(kMaxStackSize);
258 reexec = true;
259 }
260
261 if (!AddressSpaceIsUnlimited()) {
262 Report("WARNING: Program is run with limited virtual address space,"
263 " which wouldn't work with ThreadSanitizer.\n");
264 Report("Re-execing with unlimited virtual address space.\n");
265 SetAddressSpaceUnlimited();
266 reexec = true;
267 }
268 #if SANITIZER_LINUX && defined(__aarch64__)
269 // Initialize the guard pointer used in {sig}{set,long}jump.
270 InitializeGuardPtr();
271 #endif
272 if (reexec)
273 ReExec();
274 }
275
276 #ifndef SANITIZER_GO
277 CheckAndProtect();
278 InitTlsSize();
279 InitDataSeg();
280 #endif
281 }
282
IsGlobalVar(uptr addr)283 bool IsGlobalVar(uptr addr) {
284 return g_data_start && addr >= g_data_start && addr < g_data_end;
285 }
286
287 #ifndef SANITIZER_GO
288 // Extract file descriptors passed to glibc internal __res_iclose function.
289 // This is required to properly "close" the fds, because we do not see internal
290 // closes within glibc. The code is a pure hack.
ExtractResolvFDs(void * state,int * fds,int nfd)291 int ExtractResolvFDs(void *state, int *fds, int nfd) {
292 #if SANITIZER_LINUX
293 int cnt = 0;
294 struct __res_state *statp = (struct __res_state*)state;
295 for (int i = 0; i < MAXNS && cnt < nfd; i++) {
296 if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
297 fds[cnt++] = statp->_u._ext.nssocks[i];
298 }
299 return cnt;
300 #else
301 return 0;
302 #endif
303 }
304
305 // Extract file descriptors passed via UNIX domain sockets.
306 // This is requried to properly handle "open" of these fds.
307 // see 'man recvmsg' and 'man 3 cmsg'.
ExtractRecvmsgFDs(void * msgp,int * fds,int nfd)308 int ExtractRecvmsgFDs(void *msgp, int *fds, int nfd) {
309 int res = 0;
310 msghdr *msg = (msghdr*)msgp;
311 struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
312 for (; cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
313 if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
314 continue;
315 int n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(fds[0]);
316 for (int i = 0; i < n; i++) {
317 fds[res++] = ((int*)CMSG_DATA(cmsg))[i];
318 if (res == nfd)
319 return res;
320 }
321 }
322 return res;
323 }
324
325 // Note: this function runs with async signals enabled,
326 // so it must not touch any tsan state.
call_pthread_cancel_with_cleanup(int (* fn)(void * c,void * m,void * abstime),void * c,void * m,void * abstime,void (* cleanup)(void * arg),void * arg)327 int call_pthread_cancel_with_cleanup(int(*fn)(void *c, void *m,
328 void *abstime), void *c, void *m, void *abstime,
329 void(*cleanup)(void *arg), void *arg) {
330 // pthread_cleanup_push/pop are hardcore macros mess.
331 // We can't intercept nor call them w/o including pthread.h.
332 int res;
333 pthread_cleanup_push(cleanup, arg);
334 res = fn(c, m, abstime);
335 pthread_cleanup_pop(0);
336 return res;
337 }
338 #endif
339
340 #ifndef SANITIZER_GO
ReplaceSystemMalloc()341 void ReplaceSystemMalloc() { }
342 #endif
343
344 } // namespace __tsan
345
346 #endif // SANITIZER_LINUX || SANITIZER_FREEBSD
347