Implement interfaces to set and get names of threads.

At least the Linux kernel provides field where the kernel originally
stores the command which is executed by the thread.  The value can
subsequently be overwritten.  The added functions allow to do that for
threads, providing and abstraction around the syscalls or /proc file
system accesses needed.

3 files changed, 142 insertions, 0 deletions

diff --git a/nptl/sysdeps/pthread/pthread.h b/nptl/sysdeps/pthread/pthread.h
index b84fd5c7a4..44cf9f0cac 100644
--- a/nptl/sysdeps/pthread/pthread.h
+++ b/nptl/sysdeps/pthread/pthread.h
@@ -425,6 +425,18 @@ extern int pthread_setschedprio (pthread_t __target_thread, int __prio)
      __THROW;
 
 
+#ifdef __USE_GNU
+/* Get thread name visible in the kernel and its interfaces.  */
+extern int pthread_getname_np (pthread_t __target_thread, char *__buf,
+			       size_t __buflen)
+     __THROW __nonnull ((2));
+
+/* Set thread name visible in the kernel and its interfaces.  */
+extern int pthread_setname_np (pthread_t __target_thread, __const char *__name)
+     __THROW __nonnull ((2));
+#endif
+
+
 #ifdef __USE_UNIX98
 /* Determine level of concurrency.  */
 extern int pthread_getconcurrency (void) __THROW;
diff --git a/nptl/sysdeps/unix/sysv/linux/pthread_getname.c b/nptl/sysdeps/unix/sysv/linux/pthread_getname.c
new file mode 100644
index 0000000000..c6d78df39f
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/pthread_getname.c
@@ -0,0 +1,64 @@
+/* pthread_getname_np -- Get  thread name.  Linux version
+   Copyright (C) 2010 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pthreadP.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/prctl.h>
+
+#include <not-cancel.h>
+
+
+int
+pthread_getname_np (th, buf, len)
+     pthread_t th;
+     char *buf;
+     size_t len;
+{
+  const struct pthread *pd = (const struct pthread *) th;
+
+  /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
+     macro.  So we have to define it here.  */
+#define TASK_COMM_LEN 16
+  if (len < TASK_COMM_LEN)
+    return ERANGE;
+
+  if (th == THREAD_SELF)
+    return prctl (PR_SET_NAME, buf) ? errno : 0;
+
+#define FMT "/proc/self/task/%u/comm"
+  char fname[sizeof (FMT) + 8];
+  sprintf (fname, FMT, (unsigned int) pd->tid);
+
+  int fd = open_not_cancel_2 (fname, O_RDONLY);
+  if (fd == -1)
+    return errno;
+
+  int res = 0;
+  ssize_t n = TEMP_FAILURE_RETRY (read_not_cancel (fd, buf, len));
+  if (n < 0)
+    res = errno;
+
+  close_not_cancel_no_status (fd);
+
+  return res;
+}
diff --git a/nptl/sysdeps/unix/sysv/linux/pthread_setname.c b/nptl/sysdeps/unix/sysv/linux/pthread_setname.c
new file mode 100644
index 0000000000..34c08d9ea1
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/pthread_setname.c
@@ -0,0 +1,66 @@
+/* pthread_setname_np -- Set  thread name.  Linux version
+   Copyright (C) 2010 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pthreadP.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/prctl.h>
+
+#include <not-cancel.h>
+
+
+int
+pthread_setname_np (th, name)
+     pthread_t th;
+     const char *name;
+{
+  const struct pthread *pd = (const struct pthread *) th;
+
+  /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
+     macro.  So we have to define it here.  */
+#define TASK_COMM_LEN 16
+  size_t name_len = strlen (name);
+  if (name_len >= TASK_COMM_LEN)
+    return ERANGE;
+
+  if (pd == THREAD_SELF)
+    return prctl (PR_SET_NAME, name) ? errno : 0;
+
+#define FMT "/proc/self/task/%u/comm"
+  char fname[sizeof (FMT) + 8];
+  sprintf (fname, FMT, (unsigned int) pd->tid);
+
+  int fd = open_not_cancel_2 (fname, O_RDWR);
+  if (fd == -1)
+    return errno;
+
+  int res = 0;
+  ssize_t n = TEMP_FAILURE_RETRY (write_not_cancel (fd, name, name_len));
+  if (n < 0)
+    res = errno;
+  else if (n != name_len)
+    res = EIO;
+
+  close_not_cancel_no_status (fd);
+
+  return res;
+}