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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756490706; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DfwSqq/b4hHS1NgiMr1RScFvay2XswWXsOaYXHkww6Y=; b=g5hQWeuC8ni4eaT5vjHoPUlk9ZbjH4VEG+/Zn1sj2fOVAzHcuKrxWkceiXiggaVc7rtxyi NqrqVKunel2TIskqM8yXK0bPDsGBpJ7ZpY/eU+50qCvwTiAEXzhqMwdjkENNMZ+gOACKSa ffFFrwtAsCQBTRMPLI7IxaAT2WmPxBw= X-MC-Unique: CGJZAov9Pk-4sCMJqBtaTQ-1 X-Mimecast-MFC-AGG-ID: CGJZAov9Pk-4sCMJqBtaTQ_1756490680 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Stefan Weil , qemu-block@nongnu.org, Manos Pitsidianakis , "Dr. David Alan Gilbert" , Kevin Wolf , Hanna Reitz , Gerd Hoffmann , Christian Schoenebeck , Markus Armbruster , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Subject: [PATCH v2 07/14] util: add API to fetch the current thread name Date: Fri, 29 Aug 2025 19:03:47 +0100 Message-ID: <20250829180354.2922145-8-berrange@redhat.com> In-Reply-To: <20250829180354.2922145-1-berrange@redhat.com> References: <20250829180354.2922145-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1756578018656124100 This will be used to include the thread name in error reports in a later patch. It returns a const string stored in a thread local to avoid memory allocation when it is called repeatedly in a single thread. This makes the assumption that the thread name is set at the very start of the thread, which is the case when using qemu_thread_create. Signed-off-by: Daniel P. Berrang=C3=A9 --- include/qemu/thread.h | 1 + meson.build | 21 +++++++++++++++++ util/qemu-thread-posix.c | 28 ++++++++++++++++++++++- util/qemu-thread-win32.c | 49 ++++++++++++++++++++++++++++++++++++---- 4 files changed, 94 insertions(+), 5 deletions(-) diff --git a/include/qemu/thread.h b/include/qemu/thread.h index 27b888ab0a..98cc5c41ac 100644 --- a/include/qemu/thread.h +++ b/include/qemu/thread.h @@ -216,6 +216,7 @@ void qemu_thread_get_self(QemuThread *thread); bool qemu_thread_is_self(QemuThread *thread); G_NORETURN void qemu_thread_exit(void *retval); void qemu_thread_set_name(const char *name); +const char *qemu_thread_get_name(void); =20 struct Notifier; /** diff --git a/meson.build b/meson.build index 0d42de61ae..5d610224fa 100644 --- a/meson.build +++ b/meson.build @@ -2920,6 +2920,27 @@ config_host_data.set('CONFIG_PTHREAD_SET_NAME_NP', c= c.links(osdep_prefix + ''' pthread_set_name_np(thread, "QEMU"); return 0; }''', dependencies: threads)) + +config_host_data.set('CONFIG_PTHREAD_GETNAME_NP', cc.links(osdep_prefix + = ''' + #include + + int main(void) + { + char buf[16]; + pthread_getname_np(pthread_self(), buf, sizeof(buf)); + return 0; + }''', dependencies: threads)) +config_host_data.set('CONFIG_PTHREAD_GET_NAME_NP', cc.links(osdep_prefix += ''' + #include + #include + + int main(void) + { + char buf[16]; + pthread_get_name_np(pthread_self(), buf, sizeof(buf)); + return 0; + }''', dependencies: threads)) + config_host_data.set('CONFIG_PTHREAD_CONDATTR_SETCLOCK', cc.links(osdep_pr= efix + ''' #include =20 diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index 275445ed94..fbb94ca97b 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -18,7 +18,7 @@ #include "qemu/tsan.h" #include "qemu/bitmap.h" =20 -#ifdef CONFIG_PTHREAD_SET_NAME_NP +#if defined(CONFIG_PTHREAD_SET_NAME_NP) || defined(CONFIG_PTHREAD_GET_NAME= _NP) #include #endif =20 @@ -532,3 +532,29 @@ void *qemu_thread_join(QemuThread *thread) } return ret; } + +#ifndef PTHREAD_MAX_NAMELEN_NP +#define PTHREAD_MAX_NAMELEN_NP 16 +#endif + +static __thread char namebuf[PTHREAD_MAX_NAMELEN_NP]; + +const char *qemu_thread_get_name(void) +{ + int rv; + if (namebuf[0] !=3D '\0') { + return namebuf; + } + +# if defined(CONFIG_PTHREAD_GETNAME_NP) + rv =3D pthread_getname_np(pthread_self(), namebuf, sizeof(namebuf)); +# elif defined(CONFIG_PTHREAD_GET_NAME_NP) + rv =3D pthread_get_name_np(pthread_self(), namebuf, sizeof(namebuf)); +# else + rv =3D -1; +# endif + if (rv !=3D 0) { + strlcpy(namebuf, "unnamed", G_N_ELEMENTS(namebuf)); + } + return namebuf; +} diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c index 7a734a7a09..e3789c20d1 100644 --- a/util/qemu-thread-win32.c +++ b/util/qemu-thread-win32.c @@ -19,7 +19,10 @@ =20 typedef HRESULT (WINAPI *pSetThreadDescription) (HANDLE hThread, PCWSTR lpThreadDescriptio= n); +typedef HRESULT (WINAPI *pGetThreadDescription) (HANDLE hThread, + PWSTR *lpThreadDescriptio= n); static pSetThreadDescription SetThreadDescriptionFunc; +static pGetThreadDescription GetThreadDescriptionFunc; static HMODULE kernel32_module; =20 static void __attribute__((__constructor__(QEMU_CONSTRUCTOR_EARLY))) @@ -28,7 +31,7 @@ qemu_thread_init(void) qemu_thread_set_name("main"); } =20 -static bool load_set_thread_description(void) +static bool load_thread_description(void) { static gsize _init_once =3D 0; =20 @@ -38,14 +41,17 @@ static bool load_set_thread_description(void) SetThreadDescriptionFunc =3D (pSetThreadDescription)GetProcAddress(kernel32_module, "SetThreadDescriptio= n"); - if (!SetThreadDescriptionFunc) { + GetThreadDescriptionFunc =3D + (pGetThreadDescription)GetProcAddress(kernel32_module, + "GetThreadDescriptio= n"); + if (!SetThreadDescriptionFunc || !GetThreadDescriptionFunc) { FreeLibrary(kernel32_module); } } g_once_init_leave(&_init_once, 1); } =20 - return !!SetThreadDescriptionFunc; + return !!(SetThreadDescriptionFunc && GetThreadDescriptionFunc); } =20 static void error_exit(int err, const char *msg) @@ -326,7 +332,7 @@ void qemu_thread_set_name(const char *name) { g_autofree wchar_t *namew =3D NULL; =20 - if (!load_set_thread_description()) { + if (!load_thread_description()) { return; } =20 @@ -412,3 +418,38 @@ bool qemu_thread_is_self(QemuThread *thread) { return GetCurrentThreadId() =3D=3D thread->tid; } + +static __thread char namebuf[64]; + +const char *qemu_thread_get_name(void) +{ + HRESULT hr; + wchar_t *namew =3D NULL; + g_autofree char *name =3D NULL; + + if (namebuf[0] !=3D '\0') { + return namebuf; + } + + if (!load_thread_description()) { + goto error; + } + + hr =3D GetThreadDescriptionFunc(GetCurrentThread(), &namew); + if (!SUCCEEDED(hr)) { + goto error; + } + + name =3D g_utf16_to_utf8(namew, -1, NULL, NULL, NULL); + LocalFree(namew); + if (!name) { + goto error; + } + + g_strlcpy(namebuf, name, G_N_ELEMENTS(namebuf)); + return namebuf; + + error: + strlcpy(namebuf, "unnamed", G_N_ELEMENTS(namebuf)); + return namebuf; +} --=20 2.50.1