src: add uv_thread_set/getname() methods (#4599)

`uv_thread_setname()` sets the name of the current thread. Different
platforms define different limits on the max number of characters
a thread name can be: Linux, IBMi (16), macOS (64), Windows (32767),
and NetBSD (32), etc. `uv_thread_setname()` will truncate it in case
`name` is larger than the limit of the platform.

`uv_thread_getname()` gets the name of the thread specified by `tid`.
The thread name is copied into the buffer pointed to by `name`. The
`size` parameter specifies the size of the buffer pointed to by `name`.
The buffer should be large enough to hold the name of the thread plus
the trailing NUL, or it will be truncated to fit.

1 files changed, 92 insertions, 0 deletions

diff --git a/src/unix/thread.c b/src/unix/thread.c
index 4d6ddc2b..e51c2904 100644
--- a/src/unix/thread.c
+++ b/src/unix/thread.c
@@ -23,6 +23,9 @@
 #include "internal.h"
 
 #include <pthread.h>
+#ifdef __OpenBSD__
+#include <pthread_np.h>
+#endif
 #include <assert.h>
 #include <errno.h>
 
@@ -297,6 +300,18 @@ int uv_thread_equal(const uv_thread_t* t1, const uv_thread_t* t2) {
   return pthread_equal(*t1, *t2);
 }
 
+int uv_thread_setname(const char* name) {
+  if (name == NULL)
+    return UV_EINVAL;
+  return uv__thread_setname(name);
+}
+
+int uv_thread_getname(uv_thread_t* tid, char* name, size_t size) {
+  if (name == NULL || size == 0)
+    return UV_EINVAL;
+
+  return uv__thread_getname(tid, name, size);
+}
 
 int uv_mutex_init(uv_mutex_t* mutex) {
 #if defined(NDEBUG) || !defined(PTHREAD_MUTEX_ERRORCHECK)
@@ -881,3 +896,80 @@ void uv_key_set(uv_key_t* key, void* value) {
   if (pthread_setspecific(*key, value))
     abort();
 }
+
+#if defined(_AIX) || defined(__MVS__) || defined(__PASE__)
+int uv__thread_setname(const char* name) {
+  return UV_ENOSYS;
+}
+#elif defined(__APPLE__)
+int uv__thread_setname(const char* name) {
+  char namebuf[UV_PTHREAD_MAX_NAMELEN_NP];
+  strncpy(namebuf, name, sizeof(namebuf) - 1);
+  namebuf[sizeof(namebuf) - 1] = '\0';
+  int err = pthread_setname_np(namebuf);
+  if (err)
+    return UV__ERR(errno);
+  return 0;
+}
+#elif defined(__NetBSD__)
+int uv__thread_setname(const char* name) {
+  char namebuf[UV_PTHREAD_MAX_NAMELEN_NP];
+  strncpy(namebuf, name, sizeof(namebuf) - 1);
+  namebuf[sizeof(namebuf) - 1] = '\0';
+  return UV__ERR(pthread_setname_np(pthread_self(), "%s", namebuf));
+}
+#elif defined(__OpenBSD__)
+int uv__thread_setname(const char* name) {
+  char namebuf[UV_PTHREAD_MAX_NAMELEN_NP];
+  strncpy(namebuf, name, sizeof(namebuf) - 1);
+  namebuf[sizeof(namebuf) - 1] = '\0';
+  pthread_set_name_np(pthread_self(), namebuf);
+  return 0;
+}
+#else
+int uv__thread_setname(const char* name) {
+  char namebuf[UV_PTHREAD_MAX_NAMELEN_NP];
+  strncpy(namebuf, name, sizeof(namebuf) - 1);
+  namebuf[sizeof(namebuf) - 1] = '\0';
+  return UV__ERR(pthread_setname_np(pthread_self(), namebuf));
+}
+#endif
+
+#if (defined(__ANDROID_API__) && __ANDROID_API__ < 26) || \
+    defined(_AIX) || \
+    defined(__MVS__) || \
+    defined(__PASE__)
+int uv__thread_getname(uv_thread_t* tid, char* name, size_t size) {
+  return UV_ENOSYS;
+}
+#elif defined(__OpenBSD__)
+int uv__thread_getname(uv_thread_t* tid, char* name, size_t size) {
+  char thread_name[UV_PTHREAD_MAX_NAMELEN_NP];
+  pthread_get_name_np(*tid, thread_name, sizeof(thread_name));
+  strncpy(name, thread_name, size - 1);
+  name[size - 1] = '\0';
+  return 0;
+}
+#elif defined(__APPLE__)
+int uv__thread_getname(uv_thread_t* tid, char* name, size_t size) {
+  char thread_name[UV_PTHREAD_MAX_NAMELEN_NP];
+  if (pthread_getname_np(*tid, thread_name, sizeof(thread_name)) != 0)
+    return UV__ERR(errno);
+
+  strncpy(name, thread_name, size - 1);
+  name[size - 1] = '\0';
+  return 0;
+}
+#else
+int uv__thread_getname(uv_thread_t* tid, char* name, size_t size) {
+  int r;
+  char thread_name[UV_PTHREAD_MAX_NAMELEN_NP];
+  r = pthread_getname_np(*tid, thread_name, sizeof(thread_name));
+  if (r != 0)
+    return UV__ERR(r);
+
+  strncpy(name, thread_name, size - 1);
+  name[size - 1] = '\0';
+  return 0;
+}
+#endif