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
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/*--------------------------------------------------------------------*/
/*--- Support for doing system calls. syscall-x86-freebsd.S ---*/
/*--------------------------------------------------------------------*/
/*
This file is part of Valgrind, a dynamic binary instrumentation
framework.
Copyright (C) 2000-2007 Julian Seward
jseward@acm.org
Copyright (C) 2018-2021 Paul Floyd
pjfloyd@wanadoo.fr
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
The GNU General Public License is contained in the file COPYING.
*/
#include "pub_core_basics_asm.h"
#if defined(VGP_x86_freebsd)
#include "pub_core_vkiscnums_asm.h"
#include "libvex_guest_offsets.h"
/*----------------------------------------------------------------*/
/*
Perform a syscall for the client. This will run a syscall
with the client's specific per-thread signal mask.
The structure of this function is such that, if the syscall is
interrupted by a signal, we can determine exactly what
execution state we were in with respect to the execution of
the syscall by examining the value of %eip in the signal
handler. This means that we can always do the appropriate
thing to precisely emulate the kernel's signal/syscall
interactions.
The syscall number is taken from the argument, even though it
should also be in regs->m_eax. The syscall result is written
back to regs->m_eax on completion.
Returns 0 if the syscall was successfully called (even if the
syscall itself failed), or a -ve error code if one of the
sigprocmasks failed (there's no way to determine which one
failed).
VG_(fixup_guest_state_after_syscall_interrupted) does the
thread state fixup in the case where we were interrupted by a
signal.
Prototype:
Int ML_(do_syscall_for_client_WRK)(
Int syscallno, // ebp+8
void* guest_state, // ebp+12
const vki_sigset_t *sysmask, // ebp+16
const vki_sigset_t *postmask, // ebp+20
Int sigsetSzB) // ebp+24
Note that sigsetSzB is totally ignored (and irrelevant).
*/
/* from vki-darwin.h, checked at startup by m_vki.c */
#define VKI_SIG_SETMASK 3
.globl ML_(do_syscall_for_client_WRK)
ML_(do_syscall_for_client_WRK):
/* establish stack frame */
push %ebp
mov %esp, %ebp
subl $8, %esp /* 16-byte align stack */
1: /* Even though we can't take a signal until the
sigprocmask completes, start the range early.
If eip is in the range [1,2), the syscall hasn't been started yet */
/* Set the signal mask which should be current during the syscall. */
pushl 20(%ebp)
pushl 16(%ebp)
pushl $VKI_SIG_SETMASK
pushl $0xcafebabe /* totally fake return address */
movl $__NR_sigprocmask, %eax
int $0x80
jc 7f /* sigprocmask failed */
addl $16,%esp
/* Copy syscall parameters to the stack - assume no more than 8
* plus the return address */
/* do_syscall8 */
/* stack is currently aligned assuming 8 parameters */
movl 12(%ebp), %edx
movl OFFSET_x86_ESP(%edx), %edx /* edx = simulated ESP */
movl 28+4(%edx), %eax
pushl %eax
movl 24+4(%edx), %eax
pushl %eax
movl 20+4(%edx), %eax
pushl %eax
movl 16+4(%edx), %eax
pushl %eax
movl 12+4(%edx), %eax
pushl %eax
movl 8+4(%edx), %eax
pushl %eax
movl 4+4(%edx), %eax
pushl %eax
movl 0+4(%edx), %eax
pushl %eax
/* return address */
movl 0(%edx), %eax
pushl %eax
/* Put syscall number in eax */
movl 8(%ebp), %eax
/* If eip==2, then the syscall was either just about to start,
or was interrupted and the kernel was restarting it. */
2: int $0x80 /* UNIX (GrP fixme should be sysenter?) */
3: /* In the range [3, 4), the syscall result is in %eax and %edx and C,
but hasn't been committed to the thread state. */
setc 0(%esp) /* stash returned carry flag */
movl 12(%ebp), %ecx
movl %eax, OFFSET_x86_EAX(%ecx) /* save EAX to vex */
movl %edx, OFFSET_x86_EDX(%ecx) /* save EDX to vex */
/* save carry flag to vex */
subl $12, %esp
movl %ecx, 4(%esp)
movl $0, 0(%esp)
movb 12(%esp), %al
movb %al, 0(%esp)
movl $1, OFFSET_x86_SETC(%ecx)
call LibVEX_GuestX86_put_eflag_c
movl 12(%ebp), %ecx
movl $0, OFFSET_x86_SETC(%ecx)
addl $12, %esp
4: /* Re-block signals. If eip is in [4,5), then the syscall is
complete and we needn't worry about it. */
/* Set up for __pthread_sigmask(SIG_SETMASK, postmask, NULL) */
pushl $0
pushl 20(%ebp)
pushl $VKI_SIG_SETMASK
pushl $0xcafef00d /* totally fake return address */
movl $__NR_sigprocmask, %eax
int $0x80 /* should be sysenter? */
jc 7f /* sigprocmask failed */
addl $16,%esp
5: /* now safe from signals */
movl $0, %eax /* SUCCESS */
movl %ebp, %esp
popl %ebp
ret
7: /* failure: return 0x8000 | error code */
/* Note that we enter here with %esp being 16 too low
(4 extra words on the stack). But because we're nuking
the stack frame now, that doesn't matter. */
andl $0x7FFF, %eax
orl $0x8000, %eax
movl %ebp, %esp
popl %ebp
ret
.section .rodata
/* export the ranges so that
VG_(fixup_guest_state_after_syscall_interrupted) can do the
right thing */
.globl ML_(blksys_setup)
.globl ML_(blksys_restart)
.globl ML_(blksys_complete)
.globl ML_(blksys_committed)
.globl ML_(blksys_finished)
ML_(blksys_setup): .long 1b
ML_(blksys_restart): .long 2b
ML_(blksys_complete): .long 3b
ML_(blksys_committed): .long 4b
ML_(blksys_finished): .long 5b
.previous
#endif // defined(VGP_x86_freebsd)
/* Let the linker know we don't need an executable stack */
MARK_STACK_NO_EXEC
/*--------------------------------------------------------------------*/
/*--- end ---*/
/*--------------------------------------------------------------------*/
|
