1 | // Copyright (c) 2013, Google Inc. |
2 | // All rights reserved. |
3 | // |
4 | // Redistribution and use in source and binary forms, with or without |
5 | // modification, are permitted provided that the following conditions are |
6 | // met: |
7 | // |
8 | // * Redistributions of source code must retain the above copyright |
9 | // notice, this list of conditions and the following disclaimer. |
10 | // * Redistributions in binary form must reproduce the above |
11 | // copyright notice, this list of conditions and the following disclaimer |
12 | // in the documentation and/or other materials provided with the |
13 | // distribution. |
14 | // * Neither the name of Google Inc. nor the names of its |
15 | // contributors may be used to endorse or promote products derived from |
16 | // this software without specific prior written permission. |
17 | // |
18 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
19 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
20 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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24 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
25 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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27 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
28 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
29 | |
30 | #ifndef CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_ |
31 | #define CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_ |
32 | |
33 | #include <stdint.h> |
34 | #include <assert.h> |
35 | #include <string.h> |
36 | |
37 | #include "common/linux/linux_libc_support.h" |
38 | #include "third_party/lss/linux_syscall_support.h" |
39 | |
40 | namespace google_breakpad { |
41 | |
42 | // Helper class used to model a set of CPUs, as read from sysfs |
43 | // files like /sys/devices/system/cpu/present |
44 | // See See http://www.kernel.org/doc/Documentation/cputopology.txt |
45 | class CpuSet { |
46 | public: |
47 | // The maximum number of supported CPUs. |
48 | static const size_t kMaxCpus = 1024; |
49 | |
50 | CpuSet() { |
51 | my_memset(mask_, 0, sizeof(mask_)); |
52 | } |
53 | |
54 | // Parse a sysfs file to extract the corresponding CPU set. |
55 | bool ParseSysFile(int fd) { |
56 | char buffer[512]; |
57 | int ret = sys_read(fd, buffer, sizeof(buffer)-1); |
58 | if (ret < 0) |
59 | return false; |
60 | |
61 | buffer[ret] = '\0'; |
62 | |
63 | // Expected format: comma-separated list of items, where each |
64 | // item can be a decimal integer, or two decimal integers separated |
65 | // by a dash. |
66 | // E.g.: |
67 | // 0 |
68 | // 0,1,2,3 |
69 | // 0-3 |
70 | // 1,10-23 |
71 | const char* p = buffer; |
72 | const char* p_end = p + ret; |
73 | while (p < p_end) { |
74 | // Skip leading space, if any |
75 | while (p < p_end && my_isspace(*p)) |
76 | p++; |
77 | |
78 | // Find start and size of current item. |
79 | const char* item = p; |
80 | size_t item_len = static_cast<size_t>(p_end - p); |
81 | const char* item_next = |
82 | static_cast<const char*>(my_memchr(p, ',', item_len)); |
83 | if (item_next != NULL) { |
84 | p = item_next + 1; |
85 | item_len = static_cast<size_t>(item_next - item); |
86 | } else { |
87 | p = p_end; |
88 | item_next = p_end; |
89 | } |
90 | |
91 | // Ignore trailing spaces. |
92 | while (item_next > item && my_isspace(item_next[-1])) |
93 | item_next--; |
94 | |
95 | // skip empty items. |
96 | if (item_next == item) |
97 | continue; |
98 | |
99 | // read first decimal value. |
100 | uintptr_t start = 0; |
101 | const char* next = my_read_decimal_ptr(&start, item); |
102 | uintptr_t end = start; |
103 | if (*next == '-') |
104 | my_read_decimal_ptr(&end, next+1); |
105 | |
106 | while (start <= end) |
107 | SetBit(start++); |
108 | } |
109 | return true; |
110 | } |
111 | |
112 | // Intersect this CPU set with another one. |
113 | void IntersectWith(const CpuSet& other) { |
114 | for (size_t nn = 0; nn < kMaskWordCount; ++nn) |
115 | mask_[nn] &= other.mask_[nn]; |
116 | } |
117 | |
118 | // Return the number of CPUs in this set. |
119 | int GetCount() { |
120 | int result = 0; |
121 | for (size_t nn = 0; nn < kMaskWordCount; ++nn) { |
122 | result += __builtin_popcount(mask_[nn]); |
123 | } |
124 | return result; |
125 | } |
126 | |
127 | private: |
128 | void SetBit(uintptr_t index) { |
129 | size_t nn = static_cast<size_t>(index); |
130 | if (nn < kMaxCpus) |
131 | mask_[nn / kMaskWordBits] |= (1U << (nn % kMaskWordBits)); |
132 | } |
133 | |
134 | typedef uint32_t MaskWordType; |
135 | static const size_t kMaskWordBits = 8*sizeof(MaskWordType); |
136 | static const size_t kMaskWordCount = |
137 | (kMaxCpus + kMaskWordBits - 1) / kMaskWordBits; |
138 | |
139 | MaskWordType mask_[kMaskWordCount]; |
140 | }; |
141 | |
142 | } // namespace google_breakpad |
143 | |
144 | #endif // CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_ |
145 | |