1/* pthread_setname_np -- Set thread name. Linux version
2 Copyright (C) 2010-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, see <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <fcntl.h>
21#include <pthreadP.h>
22#include <stdio.h>
23#include <string.h>
24#include <unistd.h>
25#include <sys/prctl.h>
26
27#include <not-cancel.h>
28
29
30int
31pthread_setname_np (pthread_t th, const char *name)
32{
33 const struct pthread *pd = (const struct pthread *) th;
34
35 /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
36 macro. So we have to define it here. */
37#define TASK_COMM_LEN 16
38 size_t name_len = strlen (name);
39 if (name_len >= TASK_COMM_LEN)
40 return ERANGE;
41
42 if (pd == THREAD_SELF)
43 return prctl (PR_SET_NAME, name) ? errno : 0;
44
45#define FMT "/proc/self/task/%u/comm"
46 char fname[sizeof (FMT) + 8];
47 sprintf (fname, FMT, (unsigned int) pd->tid);
48
49 int fd = __open64_nocancel (fname, O_RDWR);
50 if (fd == -1)
51 return errno;
52
53 int res = 0;
54 ssize_t n = TEMP_FAILURE_RETRY (__write_nocancel (fd, name, name_len));
55 if (n < 0)
56 res = errno;
57 else if (n != name_len)
58 res = EIO;
59
60 __close_nocancel_nostatus (fd);
61
62 return res;
63}
64