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_libcsetjmp.h" // to keep _threadstate.h happy
38 #include "pub_core_threadstate.h"
39 #include "pub_core_aspacemgr.h"
40 #include "pub_core_libcbase.h"
41 #include "pub_core_libcassert.h"
42 #include "pub_core_libcprint.h"
43 #include "pub_core_machine.h"
44 #include "pub_core_options.h"
45 #include "pub_core_signals.h"
46 #include "pub_core_tooliface.h"
47 #include "pub_core_trampoline.h"
48 #include "pub_core_sigframe.h" /* self */
51 /* Cheap-ass hack copied from ppc32-aix5 code, just to get started.
52 Produce a frame with layout entirely of our own choosing. */
54 /* This module creates and removes signal frames for signal deliveries
55 on x86-darwin. Kludgey; the machine state ought to be saved in a
56 ucontext and retrieved from it later, so the handler can modify it
57 and return. However .. for now .. just stick the vex guest state
58 in the frame and snarf it again later.
60 Also, don't bother with creating siginfo and ucontext in the
61 handler, although do point them somewhere non-faulting.
63 Frame should have a 16-aligned size, just in case that turns out to
64 be important for Darwin. (be conservative)
66 struct hacky_sigframe {
67 /* first four words look like a call to a 3-arg x86 function */
72 UChar lower_guardzone[512]; // put nothing here
74 VexGuestX86State gshadow1;
75 VexGuestX86State gshadow2;
76 vki_siginfo_t fake_siginfo;
77 struct vki_ucontext fake_ucontext;
80 vki_sigset_t mask; // saved sigmask; restore when hdlr returns
82 UChar upper_guardzone[512]; // put nothing here
83 // and don't zero it, since that might overwrite the client's
84 // stack redzone, at least on archs which have one
88 /* Extend the stack segment downwards if needed so as to ensure the
89 new signal frames are mapped to something. Return a Bool
90 indicating whether or not the operation was successful.
92 static Bool extend ( ThreadState *tst, Addr addr, SizeT size )
94 ThreadId tid = tst->tid;
95 /* For tracking memory events, indicate the entire frame has been
96 allocated. Except, don't mess with the area which
97 overlaps the previous frame's redzone. */
98 /* XXX is the following call really right? compared with the
99 amd64-linux version, this doesn't appear to handle the redzone
101 VG_TRACK( new_mem_stack_signal,
102 addr - VG_STACK_REDZONE_SZB, size, tid );
107 /* Create a signal frame for thread 'tid'. Make a 3-arg frame
108 regardless of whether the client originally requested a 1-arg
109 version (no SA_SIGINFO) or a 3-arg one (SA_SIGINFO) since in the
110 former case, the x86 calling conventions will simply cause the
111 extra 2 args to be ignored (inside the handler). */
112 void VG_(sigframe_create) ( ThreadId tid,
113 Addr sp_top_of_frame,
114 const vki_siginfo_t *siginfo,
115 const struct vki_ucontext *siguc,
118 const vki_sigset_t *mask,
123 struct hacky_sigframe* frame;
124 Int sigNo = siginfo->si_signo;
126 vg_assert(VG_IS_16_ALIGNED(sizeof(struct hacky_sigframe)));
128 sp_top_of_frame &= ~0xf;
129 esp = sp_top_of_frame - sizeof(struct hacky_sigframe);
131 tst = VG_(get_ThreadState)(tid);
132 if (!extend(tst, esp, sp_top_of_frame - esp))
135 vg_assert(VG_IS_16_ALIGNED(esp));
137 frame = (struct hacky_sigframe *) esp;
139 /* clear it (very conservatively) (why so conservatively??) */
140 VG_(memset)(&frame->lower_guardzone, 0, 512);
141 VG_(memset)(&frame->gst, 0, sizeof(VexGuestX86State));
142 VG_(memset)(&frame->gshadow1, 0, sizeof(VexGuestX86State));
143 VG_(memset)(&frame->gshadow2, 0, sizeof(VexGuestX86State));
144 VG_(memset)(&frame->fake_siginfo, 0, sizeof(frame->fake_siginfo));
145 VG_(memset)(&frame->fake_ucontext, 0, sizeof(frame->fake_ucontext));
147 /* save stuff in frame */
148 frame->gst = tst->arch.vex;
149 frame->gshadow1 = tst->arch.vex_shadow1;
150 frame->gshadow2 = tst->arch.vex_shadow2;
151 frame->sigNo_private = sigNo;
152 frame->mask = tst->sig_mask;
153 frame->magicPI = 0x31415927;
155 /* Minimally fill in the siginfo and ucontext. Note, utter
156 lameness prevails. Be underwhelmed, be very underwhelmed. */
157 frame->fake_siginfo.si_signo = sigNo;
158 frame->fake_siginfo.si_code = siginfo->si_code;
160 /* Set up stack pointer */
161 vg_assert(esp == (Addr)&frame->returnAddr);
162 VG_(set_SP)(tid, esp);
163 VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_STACK_PTR, sizeof(UInt));
165 /* Set up program counter */
166 VG_(set_IP)(tid, (UInt)handler);
167 VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_INSTR_PTR, sizeof(UInt));
169 /* Set up RA and args for the frame */
170 VG_TRACK( pre_mem_write, Vg_CoreSignal, tid, "signal handler frame",
171 (Addr)frame, 4*sizeof(UInt) );
172 frame->returnAddr = (UInt)&VG_(x86_darwin_SUBST_FOR_sigreturn);
173 frame->a1_signo = sigNo;
174 frame->a2_siginfo = (UInt)&frame->fake_siginfo; /* oh well */
175 frame->a3_ucontext = (UInt)&frame->fake_ucontext; /* oh well */
176 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
177 (Addr)frame, 4*sizeof(UInt) );
178 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
179 (Addr)&frame->fake_siginfo, sizeof(frame->fake_siginfo));
180 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
181 (Addr)&frame->fake_ucontext, sizeof(frame->fake_ucontext));
183 if (VG_(clo_trace_signals))
184 VG_(message)(Vg_DebugMsg,
185 "sigframe_create (thread %d): next EIP=%#lx, next ESP=%#lx",
186 tid, (Addr)handler, (Addr)frame );
190 /* Remove a signal frame from thread 'tid's stack, and restore the CPU
191 state from it. Note, isRT is irrelevant here. */
192 void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
197 struct hacky_sigframe* frame;
199 vg_assert(VG_(is_valid_tid)(tid));
200 tst = VG_(get_ThreadState)(tid);
202 /* Check that the stack frame looks valid */
203 esp = VG_(get_SP)(tid);
205 /* why -4 ? because the signal handler's return will have popped
206 the return address of the stack; and the return address is the
207 lowest-addressed element of hacky_sigframe. */
208 frame = (struct hacky_sigframe*)(esp - 4);
209 vg_assert(frame->magicPI == 0x31415927);
210 vg_assert(VG_IS_16_ALIGNED(frame));
212 /* restore the entire guest state, and shadows, from the
213 frame. Note, as per comments above, this is a kludge - should
214 restore it from saved ucontext. Oh well. */
215 tst->arch.vex = frame->gst;
216 tst->arch.vex_shadow1 = frame->gshadow1;
217 tst->arch.vex_shadow2 = frame->gshadow2;
218 tst->sig_mask = frame->mask;
219 tst->tmp_sig_mask = frame->mask;
220 sigNo = frame->sigNo_private;
222 if (VG_(clo_trace_signals))
223 VG_(message)(Vg_DebugMsg,
224 "sigframe_destroy (thread %d): valid magic; next EIP=%#x",
225 tid, tst->arch.vex.guest_EIP);
227 VG_TRACK( die_mem_stack_signal,
228 (Addr)frame - VG_STACK_REDZONE_SZB,
229 sizeof(struct hacky_sigframe) );
232 VG_TRACK( post_deliver_signal, tid, sigNo );
235 #endif // defined(VGP_x86_darwin)
237 /*--------------------------------------------------------------------*/
239 /*--------------------------------------------------------------------*/