1//===-- sanitizer_common_libcdep.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.
11//===----------------------------------------------------------------------===//
12
13#include "sanitizer_allocator.h"
14#include "sanitizer_allocator_interface.h"
15#include "sanitizer_common.h"
16#include "sanitizer_flags.h"
17#include "sanitizer_interface_internal.h"
18#include "sanitizer_procmaps.h"
19#include "sanitizer_stackdepot.h"
20
21namespace __sanitizer {
22
23#if (SANITIZER_LINUX || SANITIZER_NETBSD) && !SANITIZER_GO
24// Weak default implementation for when sanitizer_stackdepot is not linked in.
25SANITIZER_WEAK_ATTRIBUTE StackDepotStats StackDepotGetStats() { return {}; }
26
27void *BackgroundThread(void *arg) {
28 VPrintf(1, "%s: Started BackgroundThread\n", SanitizerToolName);
29 const uptr hard_rss_limit_mb = common_flags()->hard_rss_limit_mb;
30 const uptr soft_rss_limit_mb = common_flags()->soft_rss_limit_mb;
31 const bool heap_profile = common_flags()->heap_profile;
32 uptr prev_reported_rss = 0;
33 uptr prev_reported_stack_depot_size = 0;
34 bool reached_soft_rss_limit = false;
35 uptr rss_during_last_reported_profile = 0;
36 while (true) {
37 SleepForMillis(millis: 100);
38 const uptr current_rss_mb = GetRSS() >> 20;
39 if (Verbosity()) {
40 // If RSS has grown 10% since last time, print some information.
41 if (prev_reported_rss * 11 / 10 < current_rss_mb) {
42 Printf(format: "%s: RSS: %zdMb\n", SanitizerToolName, current_rss_mb);
43 prev_reported_rss = current_rss_mb;
44 }
45 // If stack depot has grown 10% since last time, print it too.
46 StackDepotStats stack_depot_stats = StackDepotGetStats();
47 if (prev_reported_stack_depot_size * 11 / 10 <
48 stack_depot_stats.allocated) {
49 Printf(format: "%s: StackDepot: %zd ids; %zdM allocated\n", SanitizerToolName,
50 stack_depot_stats.n_uniq_ids, stack_depot_stats.allocated >> 20);
51 prev_reported_stack_depot_size = stack_depot_stats.allocated;
52 }
53 }
54 // Check RSS against the limit.
55 if (hard_rss_limit_mb && hard_rss_limit_mb < current_rss_mb) {
56 Report(format: "%s: hard rss limit exhausted (%zdMb vs %zdMb)\n",
57 SanitizerToolName, hard_rss_limit_mb, current_rss_mb);
58 DumpProcessMap();
59 Die();
60 }
61 if (soft_rss_limit_mb) {
62 if (soft_rss_limit_mb < current_rss_mb && !reached_soft_rss_limit) {
63 reached_soft_rss_limit = true;
64 Report(format: "%s: soft rss limit exhausted (%zdMb vs %zdMb)\n",
65 SanitizerToolName, soft_rss_limit_mb, current_rss_mb);
66 SetRssLimitExceeded(true);
67 } else if (soft_rss_limit_mb >= current_rss_mb &&
68 reached_soft_rss_limit) {
69 reached_soft_rss_limit = false;
70 Report(format: "%s: soft rss limit unexhausted (%zdMb vs %zdMb)\n",
71 SanitizerToolName, soft_rss_limit_mb, current_rss_mb);
72 SetRssLimitExceeded(false);
73 }
74 }
75 if (heap_profile &&
76 current_rss_mb > rss_during_last_reported_profile * 1.1) {
77 Printf(format: "\n\nHEAP PROFILE at RSS %zdMb\n", current_rss_mb);
78 __sanitizer_print_memory_profile(top_percent: 90, max_number_of_contexts: 20);
79 rss_during_last_reported_profile = current_rss_mb;
80 }
81 }
82}
83
84void MaybeStartBackgroudThread() {
85 // Need to implement/test on other platforms.
86 // Start the background thread if one of the rss limits is given.
87 if (!common_flags()->hard_rss_limit_mb &&
88 !common_flags()->soft_rss_limit_mb &&
89 !common_flags()->heap_profile) return;
90 if (!&internal_pthread_create) {
91 VPrintf(1, "%s: internal_pthread_create undefined\n", SanitizerToolName);
92 return; // Can't spawn the thread anyway.
93 }
94
95 static bool started = false;
96 if (!started) {
97 started = true;
98 internal_start_thread(func: BackgroundThread, arg: nullptr);
99 }
100}
101
102# if !SANITIZER_START_BACKGROUND_THREAD_IN_ASAN_INTERNAL
103# ifdef __clang__
104# pragma clang diagnostic push
105// We avoid global-constructors to be sure that globals are ready when
106// sanitizers need them. This can happend before global constructors executed.
107// Here we don't mind if thread is started on later stages.
108# pragma clang diagnostic ignored "-Wglobal-constructors"
109# endif
110static struct BackgroudThreadStarted {
111 BackgroudThreadStarted() { MaybeStartBackgroudThread(); }
112} background_thread_strarter UNUSED;
113# ifdef __clang__
114# pragma clang diagnostic pop
115# endif
116# endif
117#else
118void MaybeStartBackgroudThread() {}
119#endif
120
121void WriteToSyslog(const char *msg) {
122 if (!msg)
123 return;
124 InternalScopedString msg_copy;
125 msg_copy.Append(str: msg);
126 const char *p = msg_copy.data();
127
128 // Print one line at a time.
129 // syslog, at least on Android, has an implicit message length limit.
130 while (char* q = internal_strchr(s: p, c: '\n')) {
131 *q = '\0';
132 WriteOneLineToSyslog(s: p);
133 p = q + 1;
134 }
135 // Print remaining characters, if there are any.
136 // Note that this will add an extra newline at the end.
137 // FIXME: buffer extra output. This would need a thread-local buffer, which
138 // on Android requires plugging into the tools (ex. ASan's) Thread class.
139 if (*p)
140 WriteOneLineToSyslog(s: p);
141}
142
143static void (*sandboxing_callback)();
144void SetSandboxingCallback(void (*f)()) {
145 sandboxing_callback = f;
146}
147
148uptr ReservedAddressRange::InitAligned(uptr size, uptr align,
149 const char *name) {
150 CHECK(IsPowerOfTwo(align));
151 if (align <= GetPageSizeCached())
152 return Init(size, name);
153 uptr start = Init(size: size + align, name);
154 start += align - (start & (align - 1));
155 return start;
156}
157
158#if !SANITIZER_FUCHSIA
159
160// Reserve memory range [beg, end].
161// We need to use inclusive range because end+1 may not be representable.
162void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name,
163 bool madvise_shadow) {
164 CHECK_EQ((beg % GetMmapGranularity()), 0);
165 CHECK_EQ(((end + 1) % GetMmapGranularity()), 0);
166 uptr size = end - beg + 1;
167 DecreaseTotalMmap(size); // Don't count the shadow against mmap_limit_mb.
168 if (madvise_shadow ? !MmapFixedSuperNoReserve(fixed_addr: beg, size, name)
169 : !MmapFixedNoReserve(fixed_addr: beg, size, name)) {
170 Report(
171 format: "ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
172 "Perhaps you're using ulimit -v or ulimit -d\n",
173 size);
174 Die();
175 }
176 if (madvise_shadow && common_flags()->use_madv_dontdump)
177 DontDumpShadowMemory(addr: beg, length: size);
178}
179
180void ProtectGap(uptr addr, uptr size, uptr zero_base_shadow_start,
181 uptr zero_base_max_shadow_start) {
182 if (!size)
183 return;
184 void *res = MmapFixedNoAccess(fixed_addr: addr, size, name: "shadow gap");
185 if (addr == (uptr)res)
186 return;
187 // A few pages at the start of the address space can not be protected.
188 // But we really want to protect as much as possible, to prevent this memory
189 // being returned as a result of a non-FIXED mmap().
190 if (addr == zero_base_shadow_start) {
191 uptr step = GetMmapGranularity();
192 while (size > step && addr < zero_base_max_shadow_start) {
193 addr += step;
194 size -= step;
195 void *res = MmapFixedNoAccess(fixed_addr: addr, size, name: "shadow gap");
196 if (addr == (uptr)res)
197 return;
198 }
199 }
200
201 Report(
202 format: "ERROR: Failed to protect the shadow gap. "
203 "%s cannot proceed correctly. ABORTING.\n",
204 SanitizerToolName);
205 DumpProcessMap();
206 Die();
207}
208
209#endif // !SANITIZER_FUCHSIA
210
211#if !SANITIZER_WINDOWS && !SANITIZER_GO
212// Weak default implementation for when sanitizer_stackdepot is not linked in.
213SANITIZER_WEAK_ATTRIBUTE void StackDepotStopBackgroundThread() {}
214static void StopStackDepotBackgroundThread() {
215 StackDepotStopBackgroundThread();
216}
217#else
218// SANITIZER_WEAK_ATTRIBUTE is unsupported.
219static void StopStackDepotBackgroundThread() {}
220#endif
221
222void MemCpyAccessible(void *dest, const void *src, uptr n) {
223 if (TryMemCpy(dest, src, n))
224 return;
225
226 const uptr page_size = GetPageSize();
227 uptr b = reinterpret_cast<uptr>(src);
228 uptr b_up = RoundUpTo(size: b, boundary: page_size);
229
230 uptr e = reinterpret_cast<uptr>(src) + n;
231 uptr e_down = RoundDownTo(x: e, boundary: page_size);
232
233 auto copy_or_zero = [dest, src](uptr beg, uptr end) {
234 const uptr udest = reinterpret_cast<uptr>(dest);
235 const uptr usrc = reinterpret_cast<uptr>(src);
236 void *d = reinterpret_cast<void *>(udest + (beg - usrc));
237 const uptr size = end - beg;
238 if (!TryMemCpy(dest: d, src: reinterpret_cast<void *>(beg), n: size))
239 internal_memset(s: d, c: 0, n: size);
240 };
241
242 copy_or_zero(b, b_up);
243 for (uptr p = b_up; p < e_down; p += page_size)
244 copy_or_zero(p, p + page_size);
245 copy_or_zero(e_down, e);
246}
247
248} // namespace __sanitizer
249
250SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_sandbox_on_notify,
251 __sanitizer_sandbox_arguments *args) {
252 __sanitizer::StopStackDepotBackgroundThread();
253 __sanitizer::PlatformPrepareForSandboxing(args);
254 if (__sanitizer::sandboxing_callback)
255 __sanitizer::sandboxing_callback();
256}
257