threadnames.cpp

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// Copyright (c) 2018-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#include <bitcoin-build-config.h> // IWYU pragma: keep
 
#include <util/threadnames.h>
#include <util/check.h>
 
#include <algorithm>
#include <cstring>
#include <string>
 
#if (defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__))
#include <pthread.h>
#include <pthread_np.h>
#endif
 
#if __has_include(<sys/prctl.h>)
#include <sys/prctl.h>
#endif
 
#ifdef HAVE_SETTHREADDESCRIPTION
#include <windows.h>
#endif

static void SetThreadName(const char* name)
{
#if defined(PR_SET_NAME)
    // Only the first 15 characters are used (16 - NUL terminator)
    ::prctl(PR_SET_NAME, name, 0, 0, 0);
#elif (defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__))
    pthread_set_name_np(pthread_self(), name);
#elif defined(__APPLE__)
    pthread_setname_np(name);
#elif defined(HAVE_SETTHREADDESCRIPTION)
    // Thread names are ASCII-only, so widening each character is sufficient as
    // a conversion to UTF-16.
    const std::wstring wname{name, name + std::strlen(name)};
    ::SetThreadDescription(::GetCurrentThread(), wname.c_str());
#else
    // Prevent warnings for unused parameters...
    (void)name;
#endif
}

static thread_local char g_thread_name[128]{'\0'};
std::string util::ThreadGetInternalName() { return g_thread_name; }
static void SetInternalName(const std::string& name)
{
    const size_t copy_bytes{std::min(sizeof(g_thread_name) - 1, name.length())};
    std::memcpy(g_thread_name, name.data(), copy_bytes);
    g_thread_name[copy_bytes] = '\0';
}
 
void util::ThreadRename(const std::string& name)
{
    Assume(name.size() <= 13); // Linux keeps 15 bytes
    SetThreadName(("b-" + name).c_str());
    SetInternalName(name);
}
 
void util::ThreadSetInternalName(const std::string& name)
{
    SetInternalName(name);
}