pthread: Implement pthread_getname_np

Signed-off-by: Samuel Holland <samuel@sholland.org>

2 files changed, 29 insertions, 1 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 7df686f..25b57e0 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -16,6 +16,11 @@ Build system
 
 * Allow building against libobstack.
 
+pthread
+-------
+
+* Add pthread_getname_np.
+
 wchar
 -----
 
diff --git a/libgcompat/pthread.c b/libgcompat/pthread.c
index 4ebbe6b..0456c40 100644
--- a/libgcompat/pthread.c
+++ b/libgcompat/pthread.c
@@ -1,4 +1,8 @@
-#include <pthread.h>
+#define _GNU_SOURCE
+#include <errno.h>   /* errno */
+#include <fcntl.h>   /* O_CLOEXEC, O_RDONLY */
+#include <pthread.h> /* pthread_atfork */
+#include <unistd.h>  /* open, read */
 
 #include "alias.h" /* weak_alias */
 
@@ -27,3 +31,22 @@ int __register_atfork(void (*prepare)(void), void (*parent)(void),
 	return pthread_atfork(prepare, parent, child);
 }
 weak_alias(__register_atfork, register_atfork);
+
+/**
+ * Get the name of a thread.
+ */
+int pthread_getname_np(pthread_t thread, char *name, size_t len)
+{
+	int fd = open("/proc/thread-self/comm", O_RDONLY | O_CLOEXEC);
+	char dummy;
+
+	if (fd < 0)
+		return errno;
+	if (read(fd, name, len) < 0)
+		return errno;
+	/* If there's more to read, the buffer was too small. */
+	if (read(fd, &dummy, 1) > 0)
+		return ERANGE;
+
+	return 0;
+}