1 //===-- scudo_flags.cpp -----------------------------------------*- C++ -*-===//
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 /// Hardened Allocator flag parsing logic.
10 ///
11 //===----------------------------------------------------------------------===//
12 
13 #include "scudo_flags.h"
14 #include "scudo_interface_internal.h"
15 #include "scudo_utils.h"
16 
17 #include "sanitizer_common/sanitizer_flags.h"
18 #include "sanitizer_common/sanitizer_flag_parser.h"
19 
20 namespace __scudo {
21 
22 static Flags ScudoFlags;  // Use via getFlags().
23 
24 void Flags::setDefaults() {
25 #define SCUDO_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
26 #include "scudo_flags.inc"
27 #undef SCUDO_FLAG
28 }
29 
30 static void RegisterScudoFlags(FlagParser *parser, Flags *f) {
31 #define SCUDO_FLAG(Type, Name, DefaultValue, Description) \
32   RegisterFlag(parser, #Name, Description, &f->Name);
33 #include "scudo_flags.inc"
34 #undef SCUDO_FLAG
35 }
36 
37 static const char *getCompileDefinitionScudoDefaultOptions() {
38 #ifdef SCUDO_DEFAULT_OPTIONS
39   return SANITIZER_STRINGIFY(SCUDO_DEFAULT_OPTIONS);
40 #else
41   return "";
42 #endif
43 }
44 
45 static const char *getScudoDefaultOptions() {
46   return (&__scudo_default_options) ? __scudo_default_options() : "";
47 }
48 
49 void initFlags() {
50   SetCommonFlagsDefaults();
51   {
52     CommonFlags cf;
53     cf.CopyFrom(*common_flags());
54     cf.exitcode = 1;
55     OverrideCommonFlags(cf);
56   }
57   Flags *f = getFlags();
58   f->setDefaults();
59 
60   FlagParser ScudoParser;
61   RegisterScudoFlags(&ScudoParser, f);
62   RegisterCommonFlags(&ScudoParser);
63 
64   // Override from compile definition.
65   ScudoParser.ParseString(getCompileDefinitionScudoDefaultOptions());
66 
67   // Override from user-specified string.
68   ScudoParser.ParseString(getScudoDefaultOptions());
69 
70   // Override from environment.
71   ScudoParser.ParseStringFromEnv("SCUDO_OPTIONS");
72 
73   InitializeCommonFlags();
74 
75   // Sanity checks and default settings for the Quarantine parameters.
76 
77   if (f->QuarantineSizeMb >= 0) {
78     // Backward compatible logic if QuarantineSizeMb is set.
79     if (f->QuarantineSizeKb >= 0) {
80       dieWithMessage("ERROR: please use either QuarantineSizeMb (deprecated) "
81           "or QuarantineSizeKb, but not both\n");
82     }
83     if (f->QuarantineChunksUpToSize >= 0) {
84       dieWithMessage("ERROR: QuarantineChunksUpToSize cannot be used in "
85           " conjunction with the deprecated QuarantineSizeMb option\n");
86     }
87     // If everything is in order, update QuarantineSizeKb accordingly.
88     f->QuarantineSizeKb = f->QuarantineSizeMb * 1024;
89   } else {
90     // Otherwise proceed with the new options.
91     if (f->QuarantineSizeKb < 0) {
92       const int DefaultQuarantineSizeKb = FIRST_32_SECOND_64(64, 256);
93       f->QuarantineSizeKb = DefaultQuarantineSizeKb;
94     }
95     if (f->QuarantineChunksUpToSize < 0) {
96       const int DefaultQuarantineChunksUpToSize = FIRST_32_SECOND_64(512, 2048);
97       f->QuarantineChunksUpToSize = DefaultQuarantineChunksUpToSize;
98     }
99   }
100 
101   // We enforce an upper limit for the chunk quarantine threshold of 4Mb.
102   if (f->QuarantineChunksUpToSize > (4 * 1024 * 1024)) {
103     dieWithMessage("ERROR: the chunk quarantine threshold is too large\n");
104   }
105 
106   // We enforce an upper limit for the quarantine size of 32Mb.
107   if (f->QuarantineSizeKb > (32 * 1024)) {
108     dieWithMessage("ERROR: the quarantine size is too large\n");
109   }
110 
111   if (f->ThreadLocalQuarantineSizeKb < 0) {
112     const int DefaultThreadLocalQuarantineSizeKb = FIRST_32_SECOND_64(16, 64);
113     f->ThreadLocalQuarantineSizeKb = DefaultThreadLocalQuarantineSizeKb;
114   }
115   // And an upper limit of 8Mb for the thread quarantine cache.
116   if (f->ThreadLocalQuarantineSizeKb > (8 * 1024)) {
117     dieWithMessage("ERROR: the per thread quarantine cache size is too "
118         "large\n");
119   }
120   if (f->ThreadLocalQuarantineSizeKb == 0 && f->QuarantineSizeKb > 0) {
121     dieWithMessage("ERROR: ThreadLocalQuarantineSizeKb can be set to 0 only "
122         "when QuarantineSizeKb is set to 0\n");
123   }
124 }
125 
126 Flags *getFlags() {
127   return &ScudoFlags;
128 }
129 
130 }  // namespace __scudo
131 
132 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
133 SANITIZER_INTERFACE_WEAK_DEF(const char*, __scudo_default_options, void) {
134   return "";
135 }
136 #endif
137