Detect pthread_getname_np explicitly.

At least one libc (musl) defines pthread_setname_np without defining
pthread_getname_np. Detect the presence of each individually, rather than
inferring both must be defined if set is.

configure.ac

@@ -1745,6 +1745,37 @@ dnl Check if we have dlsym support.
   if test "x${je_cv_pthread_setname_np}" = "xyes" ; then
     AC_DEFINE([JEMALLOC_HAVE_PTHREAD_SETNAME_NP], [ ])
   fi
+  dnl Check if pthread_getname_np is not necessarily present despite
+  dnl the pthread_setname_np counterpart
+  JE_COMPILABLE([pthread_getname_np(3)], [
+#include <pthread.h>
+#include <stdlib.h>
+], [
+  {
+  	char *name = malloc(16);
+  	pthread_getname_np(pthread_self(), name, 16);
+	free(name);
+  }
+], [je_cv_pthread_getname_np])
+  if test "x${je_cv_pthread_getname_np}" = "xyes" ; then
+    AC_DEFINE([JEMALLOC_HAVE_PTHREAD_GETNAME_NP], [ ])
+  fi
+  dnl Check if pthread_get_name_np is not necessarily present despite
+  dnl the pthread_set_name_np counterpart
+  JE_COMPILABLE([pthread_get_name_np(3)], [
+#include <pthread.h>
+#include <pthread_np.h>
+#include <stdlib.h>
+], [
+  {
+  	char *name = malloc(16);
+  	pthread_get_name_np(pthread_self(), name, 16);
+	free(name);
+  }
+], [je_cv_pthread_get_name_np])
+  if test "x${je_cv_pthread_get_name_np}" = "xyes" ; then
+    AC_DEFINE([JEMALLOC_HAVE_PTHREAD_GET_NAME_NP], [ ])
+  fi
 fi
 
 JE_APPEND_VS(CPPFLAGS, -D_REENTRANT)

include/jemalloc/internal/jemalloc_internal_defs.h.in

@@ -85,6 +85,12 @@
 /* Defined if pthread_setname_np(3) is available. */
 #undef JEMALLOC_HAVE_PTHREAD_SETNAME_NP
 
+/* Defined if pthread_getname_np(3) is available. */
+#undef JEMALLOC_HAVE_PTHREAD_GETNAME_NP
+
+/* Defined if pthread_get_name_np(3) is available. */
+#undef JEMALLOC_HAVE_PTHREAD_GET_NAME_NP
+
 /*
  * Defined if clock_gettime(CLOCK_MONOTONIC_COARSE, ...) is available.
  */

src/prof_sys.c

@@ -292,8 +292,11 @@ void prof_unwind_init() {
 
 static int
 prof_sys_thread_name_read_impl(char *buf, size_t limit) {
-#ifdef JEMALLOC_HAVE_PTHREAD_SETNAME_NP
+#if defined(JEMALLOC_HAVE_PTHREAD_GETNAME_NP)
 	return pthread_getname_np(pthread_self(), buf, limit);
+#elif defined(JEMALLOC_HAVE_PTHREAD_GET_NAME_NP)
+	pthread_get_name_np(pthread_self(), buf, limit);
+	return 0;
 #else
 	return ENOSYS;
 #endif