74 lines
1.3 KiB
C++
74 lines
1.3 KiB
C++
#include "SharedMemory.h"
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#include "RandomUtils.h"
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#ifdef __linux__
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#endif
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void SharedMemory::allocate(const std::string& namePrefix, std::size_t size)
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{
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createFile(namePrefix);
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if (!mIsValid)
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{
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return;
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}
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#ifdef __linux__
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int ret{-1};
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do {
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ret = ftruncate(mFileDescriptor, size);
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} while (ret < 0 && errno == EINTR);
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if (ret < 0)
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{
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close(mFileDescriptor);
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mIsValid = false;
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}
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#endif
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}
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int SharedMemory::getFileDescriptor() const
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{
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return mFileDescriptor;
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}
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bool SharedMemory::isValid() const
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{
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return mIsValid;
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}
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void SharedMemory::createFile(const std::string& namePrefix)
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{
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#ifdef __linux__
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unsigned retries = 100;
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do {
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const auto name = getRandomName(namePrefix);
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--retries;
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const int fd = shm_open(name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600);
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if (fd >= 0)
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{
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shm_unlink(name.c_str());
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mFileDescriptor = fd;
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mIsValid = true;
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break;
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}
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} while (retries > 0 && errno == EEXIST);
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#endif
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}
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std::string SharedMemory::getRandomName(const std::string& namePrefix) const
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{
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std::string randomSuffix;
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for (const auto entry : RandomUtils::getRandomVecUnsigned(6))
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{
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randomSuffix += std::to_string(entry);
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}
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return namePrefix + randomSuffix;
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}
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