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// Copyright (c) 2013, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_
#define CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_
#include <stdint.h>
#include <assert.h>
#include <string.h>
#include "common/linux/linux_libc_support.h"
#include "third_party/lss/linux_syscall_support.h"
namespace google_breakpad {
// Helper class used to model a set of CPUs, as read from sysfs
// files like /sys/devices/system/cpu/present
class CpuSet {
public:
// The maximum number of supported CPUs.
static const size_t kMaxCpus = 1024;
CpuSet() {
my_memset(mask_, 0, sizeof(mask_));
}
// Parse a sysfs file to extract the corresponding CPU set.
bool ParseSysFile(int fd) {
char buffer[512];
int ret = sys_read(fd, buffer, sizeof(buffer)-1);
if (ret < 0)
return false;
buffer[ret] = '\0';
// Expected format: comma-separated list of items, where each
// item can be a decimal integer, or two decimal integers separated
// by a dash.
// E.g.:
// 0
// 0,1,2,3
// 0-3
// 1,10-23
const char* p = buffer;
const char* p_end = p + ret;
while (p < p_end) {
// Skip leading space, if any
while (p < p_end && my_isspace(*p))
p++;
// Find start and size of current item.
const char* item = p;
size_t item_len = static_cast<size_t>(p_end - p);
const char* item_next =
static_cast<const char*>(my_memchr(p, ',', item_len));
if (item_next != NULL) {
p = item_next + 1;
item_len = static_cast<size_t>(item_next - item);
} else {
p = p_end;
item_next = p_end;
}
// Ignore trailing spaces.
while (item_next > item && my_isspace(item_next[-1]))
item_next--;
// skip empty items.
if (item_next == item)
continue;
// read first decimal value.
uintptr_t start = 0;
const char* next = my_read_decimal_ptr(&start, item);
uintptr_t end = start;
if (*next == '-')
my_read_decimal_ptr(&end, next+1);
while (start <= end)
SetBit(start++);
}
return true;
}
// Intersect this CPU set with another one.
void IntersectWith(const CpuSet& other) {
for (size_t nn = 0; nn < kMaskWordCount; ++nn)
mask_[nn] &= other.mask_[nn];
}
// Return the number of CPUs in this set.
int GetCount() {
int result = 0;
for (size_t nn = 0; nn < kMaskWordCount; ++nn) {
result += __builtin_popcount(mask_[nn]);
}
return result;
}
private:
void SetBit(uintptr_t index) {
size_t nn = static_cast<size_t>(index);
if (nn < kMaxCpus)
mask_[nn / kMaskWordBits] |= (1U << (nn % kMaskWordBits));
}
typedef uint32_t MaskWordType;
static const size_t kMaskWordBits = 8*sizeof(MaskWordType);
static const size_t kMaskWordCount =
(kMaxCpus + kMaskWordBits - 1) / kMaskWordBits;
MaskWordType mask_[kMaskWordCount];
};
} // namespace google_breakpad
#endif // CLIENT_LINUX_MINIDUMP_WRITER_CPU_SET_H_