1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
/* Create a thread.
Copyright (C) 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Bruno Haible <bruno@clisp.org>, 2002.
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; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#define __clone __no_broken_clone_decl
#include <sched.h>
#include <sys/rfork.h>
#include <errno.h>
#include <signal.h>
#include <stddef.h>
#include <getosreldate.h>
#undef __clone
/* __start_thread (flags, child_stack, fn, arg)
is roughly equivalent to
int retval = __rfork (flags);
if (retval == 0)
{
// Here we are in the child thread.
%stackpointer = child_stack;
_exit (fn (arg));
}
return retval;
but it cannot be done in portable C because it must access fn and arg
after having replaced the stack pointer. */
extern int __start_thread (int flags, void *child_stack,
int (*fn) (void *), void *arg);
int __clone (int (*fn) (void *), void *child_stack, int flags, void *arg)
{
int rfork_flags = RFPROC;
if (fn == NULL || child_stack == NULL)
{
__set_errno (EINVAL);
return -1;
}
/* This implementation of clone() does not support all Linux flags. */
if (flags & ~(CSIGNAL | CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
| CLONE_VFORK | CLONE_SYSVSEM))
{
__set_errno (EINVAL);
return -1;
}
if ((flags & CSIGNAL) != SIGCHLD)
{
if (__kernel_getosreldate() >= 802510)
/* we slightly cheat here, */
/* the 9.x snapshot prior to r223966 does not support it too */
{
if ((flags & CSIGNAL) & ~RFTSIGMASK)
{
__set_errno (EINVAL);
return -1;
}
rfork_flags |= (RFTSIGZMB | RFTSIGFLAGS(flags & CSIGNAL));
}
else
{
if ((flags & CSIGNAL) & ~RFTHPNMASK)
{
__set_errno (EINVAL);
return -1;
}
if ((flags & CSIGNAL) == 0)
rfork_flags |= (RFLINUXTHPN | ((SIGCHLD) << RFTHPNSHIFT));
else
rfork_flags |= (RFLINUXTHPN | ((flags & CSIGNAL) << RFTHPNSHIFT));
}
}
if (flags & CLONE_VM)
rfork_flags |= RFMEM;
if (flags & CLONE_FS)
/* Sharing the filesystem related info (umask, cwd, root dir)
is not supported by rfork. Ignore this; let's hope programs
will set their umask and cwd before spawning threads. */
;
if (flags & CLONE_SYSVSEM)
/* Ignore this; it has been introduced into linuxthreads in post 2.4 glibc */
;
if (!(flags & CLONE_FILES))
rfork_flags |= RFFDG;
if (flags & CLONE_SIGHAND)
{
rfork_flags |= RFSIGSHARE;
/* Also set the undocumented flag RFTHREAD. It has the effect that when
the thread leader exits, all threads belonging to it are killed. */
rfork_flags |= RFTHREAD;
}
if (flags & CLONE_VFORK)
rfork_flags |= RFPPWAIT;
return __start_thread (rfork_flags, child_stack, fn, arg);
}
weak_alias (__clone, clone)
|
