2 /*--------------------------------------------------------------------*/
3 /*--- Create/destroy signal delivery frames. ---*/
4 /*--- sigframe-x86-darwin.c ---*/
5 /*--------------------------------------------------------------------*/
8 This file is part of Valgrind, a dynamic binary instrumentation
11 Copyright (C) 2006-2010 OpenWorks Ltd
14 This program is free software; you can redistribute it and/or
15 modify it under the terms of the GNU General Public License as
16 published by the Free Software Foundation; either version 2 of the
17 License, or (at your option) any later version.
19 This program is distributed in the hope that it will be useful, but
20 WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 General Public License for more details.
24 You should have received a copy of the GNU General Public License
25 along with this program; if not, write to the Free Software
26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
29 The GNU General Public License is contained in the file COPYING.
32 #if defined(VGP_x86_darwin)
34 #include "pub_core_basics.h"
35 #include "pub_core_vki.h"
36 #include "pub_core_vkiscnums.h"
37 #include "pub_core_threadstate.h"
38 #include "pub_core_aspacemgr.h"
39 #include "pub_core_libcbase.h"
40 #include "pub_core_libcassert.h"
41 #include "pub_core_libcprint.h"
42 #include "pub_core_machine.h"
43 #include "pub_core_options.h"
44 #include "pub_core_signals.h"
45 #include "pub_core_tooliface.h"
46 #include "pub_core_trampoline.h"
47 #include "pub_core_sigframe.h" /* self */
50 /* Cheap-ass hack copied from ppc32-aix5 code, just to get started.
51 Produce a frame with layout entirely of our own choosing. */
53 /* This module creates and removes signal frames for signal deliveries
54 on x86-darwin. Kludgey; the machine state ought to be saved in a
55 ucontext and retrieved from it later, so the handler can modify it
56 and return. However .. for now .. just stick the vex guest state
57 in the frame and snarf it again later.
59 Also, don't bother with creating siginfo and ucontext in the
60 handler, although do point them somewhere non-faulting.
62 Frame should have a 16-aligned size, just in case that turns out to
63 be important for Darwin. (be conservative)
65 struct hacky_sigframe {
66 /* first four words look like a call to a 3-arg x86 function */
71 UChar lower_guardzone[512]; // put nothing here
73 VexGuestX86State gshadow1;
74 VexGuestX86State gshadow2;
75 vki_siginfo_t fake_siginfo;
76 struct vki_ucontext fake_ucontext;
79 vki_sigset_t mask; // saved sigmask; restore when hdlr returns
81 UChar upper_guardzone[512]; // put nothing here
85 /* Extend the stack segment downwards if needed so as to ensure the
86 new signal frames are mapped to something. Return a Bool
87 indicating whether or not the operation was successful.
89 static Bool extend ( ThreadState *tst, Addr addr, SizeT size )
91 ThreadId tid = tst->tid;
92 /* For tracking memory events, indicate the entire frame has been
93 allocated. Except, don't mess with the area which
94 overlaps the previous frame's redzone. */
95 /* XXX is the following call really right? compared with the
96 amd64-linux version, this doesn't appear to handle the redzone
98 VG_TRACK( new_mem_stack_signal,
99 addr, size - VG_STACK_REDZONE_SZB, tid );
104 /* Create a signal frame for thread 'tid'. Make a 3-arg frame
105 regardless of whether the client originally requested a 1-arg
106 version (no SA_SIGINFO) or a 3-arg one (SA_SIGINFO) since in the
107 former case, the x86 calling conventions will simply cause the
108 extra 2 args to be ignored (inside the handler). */
109 void VG_(sigframe_create) ( ThreadId tid,
110 Addr sp_top_of_frame,
111 const vki_siginfo_t *siginfo,
112 const struct vki_ucontext *siguc,
115 const vki_sigset_t *mask,
120 struct hacky_sigframe* frame;
121 Int sigNo = siginfo->si_signo;
123 vg_assert(VG_IS_16_ALIGNED(sizeof(struct hacky_sigframe)));
125 sp_top_of_frame &= ~0xf;
126 esp = sp_top_of_frame - sizeof(struct hacky_sigframe);
128 tst = VG_(get_ThreadState)(tid);
129 if (!extend(tst, esp, sp_top_of_frame - esp))
132 vg_assert(VG_IS_16_ALIGNED(esp));
134 frame = (struct hacky_sigframe *) esp;
136 /* clear it (very conservatively) (why so conservatively??) */
137 VG_(memset)(&frame->lower_guardzone, 0, 512);
138 VG_(memset)(&frame->gst, 0, sizeof(VexGuestX86State));
139 VG_(memset)(&frame->gshadow1, 0, sizeof(VexGuestX86State));
140 VG_(memset)(&frame->gshadow2, 0, sizeof(VexGuestX86State));
141 VG_(memset)(&frame->fake_siginfo, 0, sizeof(frame->fake_siginfo));
142 VG_(memset)(&frame->fake_ucontext, 0, sizeof(frame->fake_ucontext));
144 /* save stuff in frame */
145 frame->gst = tst->arch.vex;
146 frame->gshadow1 = tst->arch.vex_shadow1;
147 frame->gshadow2 = tst->arch.vex_shadow2;
148 frame->sigNo_private = sigNo;
149 frame->mask = tst->sig_mask;
150 frame->magicPI = 0x31415927;
152 /* Minimally fill in the siginfo and ucontext. Note, utter
153 lameness prevails. Be underwhelmed, be very underwhelmed. */
154 frame->fake_siginfo.si_signo = sigNo;
155 frame->fake_siginfo.si_code = siginfo->si_code;
157 /* Set up stack pointer */
158 vg_assert(esp == (Addr)&frame->returnAddr);
159 VG_(set_SP)(tid, esp);
160 VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_STACK_PTR, sizeof(UInt));
162 /* Set up program counter */
163 VG_(set_IP)(tid, (UInt)handler);
164 VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_INSTR_PTR, sizeof(UInt));
166 /* Set up RA and args for the frame */
167 VG_TRACK( pre_mem_write, Vg_CoreSignal, tid, "signal handler frame",
168 (Addr)frame, 4*sizeof(UInt) );
169 frame->returnAddr = (UInt)&VG_(x86_darwin_SUBST_FOR_sigreturn);
170 frame->a1_signo = sigNo;
171 frame->a2_siginfo = (UInt)&frame->fake_siginfo; /* oh well */
172 frame->a3_ucontext = (UInt)&frame->fake_ucontext; /* oh well */
173 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
174 (Addr)frame, 4*sizeof(UInt) );
175 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
176 (Addr)&frame->fake_siginfo, sizeof(frame->fake_siginfo));
177 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
178 (Addr)&frame->fake_ucontext, sizeof(frame->fake_ucontext));
180 if (VG_(clo_trace_signals))
181 VG_(message)(Vg_DebugMsg,
182 "sigframe_create (thread %d): next EIP=%#lx, next ESP=%#lx",
183 tid, (Addr)handler, (Addr)frame );
187 /* Remove a signal frame from thread 'tid's stack, and restore the CPU
188 state from it. Note, isRT is irrelevant here. */
189 void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
194 struct hacky_sigframe* frame;
196 vg_assert(VG_(is_valid_tid)(tid));
197 tst = VG_(get_ThreadState)(tid);
199 /* Check that the stack frame looks valid */
200 esp = VG_(get_SP)(tid);
202 /* why -4 ? because the signal handler's return will have popped
203 the return address of the stack; and the return address is the
204 lowest-addressed element of hacky_sigframe. */
205 frame = (struct hacky_sigframe*)(esp - 4);
206 vg_assert(frame->magicPI == 0x31415927);
207 vg_assert(VG_IS_16_ALIGNED(frame));
209 /* restore the entire guest state, and shadows, from the
210 frame. Note, as per comments above, this is a kludge - should
211 restore it from saved ucontext. Oh well. */
212 tst->arch.vex = frame->gst;
213 tst->arch.vex_shadow1 = frame->gshadow1;
214 tst->arch.vex_shadow2 = frame->gshadow2;
215 tst->sig_mask = frame->mask;
216 tst->tmp_sig_mask = frame->mask;
217 sigNo = frame->sigNo_private;
219 if (VG_(clo_trace_signals))
220 VG_(message)(Vg_DebugMsg,
221 "sigframe_destroy (thread %d): valid magic; next EIP=%#x",
222 tid, tst->arch.vex.guest_EIP);
224 VG_TRACK( die_mem_stack_signal,
226 sizeof(struct hacky_sigframe) - VG_STACK_REDZONE_SZB );
229 VG_TRACK( post_deliver_signal, tid, sigNo );
232 #endif // defined(VGP_x86_darwin)
234 /*--------------------------------------------------------------------*/
236 /*--------------------------------------------------------------------*/