1 /* Copyright (C) 2002, 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19 #include <assert.h>
20 #include <errno.h>
21 #include <inttypes.h>
22 #include <stdio.h>
23 #include <stdio_ext.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <sys/resource.h>
27 #include "pthreadP.h"
28 #include <lowlevellock.h>
29 #include <ldsodefs.h>
30
31
32 int
pthread_getattr_np(pthread_t thread_id,pthread_attr_t * attr)33 pthread_getattr_np (
34 pthread_t thread_id,
35 pthread_attr_t *attr)
36 {
37 struct pthread *thread = (struct pthread *) thread_id;
38 struct pthread_attr *iattr = (struct pthread_attr *) attr;
39 int ret = 0;
40
41 lll_lock (thread->lock, LLL_PRIVATE);
42
43 /* The thread library is responsible for keeping the values in the
44 thread desriptor up-to-date in case the user changes them. */
45 memcpy (&iattr->schedparam, &thread->schedparam,
46 sizeof (struct sched_param));
47 iattr->schedpolicy = thread->schedpolicy;
48
49 /* Clear the flags work. */
50 iattr->flags = thread->flags;
51
52 /* The thread might be detached by now. */
53 if (IS_DETACHED (thread))
54 iattr->flags |= ATTR_FLAG_DETACHSTATE;
55
56 /* This is the guardsize after adjusting it. */
57 iattr->guardsize = thread->reported_guardsize;
58
59 /* The sizes are subject to alignment. */
60 if (__builtin_expect (thread->stackblock != NULL, 1))
61 {
62 iattr->stacksize = thread->stackblock_size;
63 iattr->stackaddr = (char *) thread->stackblock + iattr->stacksize;
64 }
65 else
66 {
67 /* No stack information available. This must be for the initial
68 thread. Get the info in some magical way. */
69 assert (abs (thread->pid) == thread->tid);
70
71 /* Stack size limit. */
72 struct rlimit rl;
73
74 /* The safest way to get the top of the stack is to read
75 /proc/self/maps and locate the line into which
76 __libc_stack_end falls. */
77 FILE *fp = fopen ("/proc/self/maps", "rc");
78 if (fp == NULL)
79 ret = errno;
80 /* We need the limit of the stack in any case. */
81 else
82 {
83 if (getrlimit (RLIMIT_STACK, &rl) != 0)
84 ret = errno;
85 else
86 {
87 /* We need no locking. */
88 __fsetlocking (fp, FSETLOCKING_BYCALLER);
89
90 /* Until we found an entry (which should always be the case)
91 mark the result as a failure. */
92 ret = ENOENT;
93
94 char *line = NULL;
95 size_t linelen = 0;
96 uintptr_t last_to = 0;
97
98 while (! feof_unlocked (fp))
99 {
100 if (getdelim (&line, &linelen, '\n', fp) <= 0)
101 break;
102
103 uintptr_t from;
104 uintptr_t to;
105 if (sscanf (line, "%" SCNxPTR "-%" SCNxPTR, &from, &to) != 2)
106 continue;
107 if (from <= (uintptr_t) __libc_stack_end
108 && (uintptr_t) __libc_stack_end < to)
109 {
110 /* Found the entry. Now we have the info we need. */
111 iattr->stacksize = rl.rlim_cur;
112 iattr->stackaddr = (void *) to;
113
114 /* The limit might be too high. */
115 if ((size_t) iattr->stacksize
116 > (size_t) iattr->stackaddr - last_to)
117 iattr->stacksize = (size_t) iattr->stackaddr - last_to;
118
119 /* We succeed and no need to look further. */
120 ret = 0;
121 break;
122 }
123 last_to = to;
124 }
125
126 free (line);
127 }
128
129 fclose (fp);
130 }
131 }
132
133 iattr->flags |= ATTR_FLAG_STACKADDR;
134
135 if (ret == 0)
136 {
137 size_t size = 16;
138 cpu_set_t *cpuset = NULL;
139
140 do
141 {
142 size <<= 1;
143
144 void *newp = realloc (cpuset, size);
145 if (newp == NULL)
146 {
147 ret = ENOMEM;
148 break;
149 }
150 cpuset = (cpu_set_t *) newp;
151
152 ret = __pthread_getaffinity_np (thread_id, size, cpuset);
153 }
154 /* Pick some ridiculous upper limit. Is 8 million CPUs enough? */
155 while (ret == EINVAL && size < 1024 * 1024);
156
157 if (ret == 0)
158 {
159 iattr->cpuset = cpuset;
160 iattr->cpusetsize = size;
161 }
162 else
163 {
164 free (cpuset);
165 if (ret == ENOSYS)
166 {
167 /* There is no such functionality. */
168 ret = 0;
169 iattr->cpuset = NULL;
170 iattr->cpusetsize = 0;
171 }
172 }
173 }
174
175 lll_unlock (thread->lock, LLL_PRIVATE);
176
177 return ret;
178 }
179