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#include "mlock.h"
#include <stdio.h>
#include <sys/mman.h>
#include <stdint.h>
#include <inttypes.h>
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
void PopulateFile(void* ptr, size_t size)
{
constexpr size_t PageSize = 4096;
auto* begin = static_cast<volatile char*>(ptr);
for (auto* current = begin; current < begin + size; current += PageSize) {
*current;
}
}
bool MlockFileMappings(bool populate)
{
auto* file = ::fopen("/proc/self/maps", "r");
if (!file) {
return false;
}
// Each line of /proc/<pid>/smaps has the following format:
// address perms offset dev inode path
// E.g.
// 08048000-08056000 r-xp 00000000 03:0c 64593 /usr/sbin/gpm
bool failed = false;
while (true) {
char line[1024];
if (!fgets(line, sizeof(line), file)) {
break;
}
char addressStr[64];
char permsStr[64];
char offsetStr[64];
char devStr[64];
int inode;
if (sscanf(line, "%s %s %s %s %d",
addressStr,
permsStr,
offsetStr,
devStr,
&inode) != 5)
{
continue;
}
if (inode == 0) {
continue;
}
if (permsStr[0] != 'r') {
continue;
}
uintptr_t startAddress;
uintptr_t endAddress;
if (sscanf(addressStr, "%" PRIx64 "-%" PRIx64,
&startAddress,
&endAddress) != 2)
{
continue;
}
if (::mlock(reinterpret_cast<const void*>(startAddress), endAddress - startAddress) != 0) {
failed = true;
continue;
}
if (populate) {
PopulateFile(reinterpret_cast<void*>(startAddress), endAddress - startAddress);
}
}
::fclose(file);
return !failed;
}
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
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