2 * Copyright (c) 2019 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/cdefs.h>
36 #include <sys/types.h>
37 #include <sys/syscall.h>
38 #include <sys/upmap.h>
41 #include <machine/cpufunc.h>
42 #include <machine/tls.h>
48 /*#include "un-namespace.h"*/
49 #include "libc_private.h"
52 extern int __sys_lwp_setname(lwpid_t tid, const char *name);
53 extern int __sys_lwp_getname(lwpid_t tid, char *name, size_t len);
54 int __lwp_setname(lwpid_t tid, const char *name);
55 int __lwp_getname(lwpid_t tid, char *name, size_t len);
57 static int fast_setname_count;
58 static __thread int fast_setname_state TLS_ATTRIBUTE;
59 static __thread char *thread_title TLS_ATTRIBUTE;
60 static __thread lwpid_t *thread_tid TLS_ATTRIBUTE;
63 * Optimize lwp_setname() if it is called a lot by using the lpmap to
64 * directly copy the name without making a system call. The optimization
65 * only operates when setting the name for the calling thread.
68 __lwp_setname(lwpid_t tid, const char *name)
70 if (fast_setname_state == 0 && fast_setname_count++ >= 10) {
71 __lpmap_map(&thread_title, &fast_setname_state,
73 __lpmap_map(&thread_tid, &fast_setname_state,
75 __lpmap_map(NULL, &fast_setname_state, 0);
77 if (fast_setname_state > 0 && tid == *thread_tid) {
78 size_t len = strlen(name);
80 if (len >= LPMAP_MAXTHREADTITLE)
81 len = LPMAP_MAXTHREADTITLE - 1;
82 thread_title[len] = 0;
83 bcopy(name, thread_title, len);
86 return(__sys_lwp_setname(tid, name));
90 __weak_reference(__lwp_setname, lwp_setname);
93 * Optimize lwp_getname() the same way, and as with lwp_setname() the
94 * optimization is only applicable for the current thread.
97 __lwp_getname(lwpid_t tid, char *name, size_t len)
99 if (fast_setname_state == 0 && fast_setname_count++ >= 10) {
100 __lpmap_map(&thread_title, &fast_setname_state,
101 LPTYPE_THREAD_TITLE);
102 __lpmap_map(&thread_tid, &fast_setname_state,
104 __lpmap_map(NULL, &fast_setname_state, 0);
106 if (fast_setname_state > 0 && tid == *thread_tid) {
107 snprintf(name, len, "%s", thread_title);
110 return __sys_lwp_getname(tid, name, len);
114 __weak_reference(__lwp_getname, lwp_getname);