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android / platform / external / valgrind / 2333583 / . / coregrind / m_syswrap / syswrap-main.c
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/*--------------------------------------------------------------------*/
/*--- Handle system calls. syswrap-main.c ---*/
/*--------------------------------------------------------------------*/
/*
This file is part of Valgrind, a dynamic binary instrumentation
framework.
Copyright (C) 2000-2013 Julian Seward
jseward@acm.org
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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA.
The GNU General Public License is contained in the file COPYING.
*/
#include "libvex_guest_offsets.h"
#include "libvex_trc_values.h"
#include "pub_core_basics.h"
#include "pub_core_aspacemgr.h"
#include "pub_core_vki.h"
#include "pub_core_vkiscnums.h"
#include "pub_core_libcsetjmp.h" // to keep _threadstate.h happy
#include "pub_core_threadstate.h"
#include "pub_core_libcbase.h"
#include "pub_core_libcassert.h"
#include "pub_core_libcprint.h"
#include "pub_core_libcproc.h" // For VG_(getpid)()
#include "pub_core_libcsignal.h"
#include "pub_core_scheduler.h" // For VG_({acquire,release}_BigLock),
// and VG_(vg_yield)
#include "pub_core_stacktrace.h" // For VG_(get_and_pp_StackTrace)()
#include "pub_core_tooliface.h"
#include "pub_core_options.h"
#include "pub_core_signals.h" // For VG_SIGVGKILL, VG_(poll_signals)
#include "pub_core_syscall.h"
#include "pub_core_machine.h"
#include "pub_core_syswrap.h"
#include "priv_types_n_macros.h"
#include "priv_syswrap-main.h"
#if defined(VGO_darwin)
#include "priv_syswrap-darwin.h"
#endif
/* Useful info which needs to be recorded somewhere:
Use of registers in syscalls is:
NUM ARG1 ARG2 ARG3 ARG4 ARG5 ARG6 ARG7 ARG8 RESULT
LINUX:
x86 eax ebx ecx edx esi edi ebp n/a n/a eax (== NUM)
amd64 rax rdi rsi rdx r10 r8 r9 n/a n/a rax (== NUM)
ppc32 r0 r3 r4 r5 r6 r7 r8 n/a n/a r3+CR0.SO (== ARG1)
ppc64 r0 r3 r4 r5 r6 r7 r8 n/a n/a r3+CR0.SO (== ARG1)
arm r7 r0 r1 r2 r3 r4 r5 n/a n/a r0 (== ARG1)
mips32 v0 a0 a1 a2 a3 stack stack n/a n/a v0 (== NUM)
mips64 v0 a0 a1 a2 a3 a4 a5 a6 a7 v0 (== NUM)
arm64 x8 x0 x1 x2 x3 x4 x5 n/a n/a x0 ?? (== ARG1??)
On s390x the svc instruction is used for system calls. The system call
number is encoded in the instruction (8 bit immediate field). Since Linux
2.6 it is also allowed to use svc 0 with the system call number in r1.
This was introduced for system calls >255, but works for all. It is
also possible to see the svc 0 together with an EXecute instruction, that
fills in the immediate field.
s390x r1/SVC r2 r3 r4 r5 r6 r7 n/a n/a r2 (== ARG1)
DARWIN:
x86 eax +4 +8 +12 +16 +20 +24 +28 +32 edx:eax, eflags.c
amd64 rax rdi rsi rdx rcx r8 r9 +8 +16 rdx:rax, rflags.c
For x86-darwin, "+N" denotes "in memory at N(%esp)"; ditto
amd64-darwin. Apparently 0(%esp) is some kind of return address
(perhaps for syscalls done with "sysenter"?) I don't think it is
relevant for syscalls done with "int $0x80/1/2".
*/
/* This is the top level of the system-call handler module. All
system calls are channelled through here, doing two things:
* notify the tool of the events (mem/reg reads, writes) happening
* perform the syscall, usually by passing it along to the kernel
unmodified.
A magical piece of assembly code, do_syscall_for_client_WRK, in
syscall-$PLATFORM.S does the tricky bit of passing a syscall to the
kernel, whilst having the simulator retain control.
*/
/* The main function is VG_(client_syscall). The simulation calls it
whenever a client thread wants to do a syscall. The following is a
sketch of what it does.
* Ensures the root thread's stack is suitably mapped. Tedious and
arcane. See big big comment in VG_(client_syscall).
* First, it rounds up the syscall number and args (which is a
platform dependent activity) and puts them in a struct ("args")
and also a copy in "orig_args".
The pre/post wrappers refer to these structs and so no longer
need magic macros to access any specific registers. This struct
is stored in thread-specific storage.
* The pre-wrapper is called, passing it a pointer to struct
"args".
* The pre-wrapper examines the args and pokes the tool
appropriately. It may modify the args; this is why "orig_args"
is also stored.
The pre-wrapper may choose to 'do' the syscall itself, and
concludes one of three outcomes:
Success(N) -- syscall is already complete, with success;
result is N
Fail(N) -- syscall is already complete, with failure;
error code is N
HandToKernel -- (the usual case): this needs to be given to
the kernel to be done, using the values in
the possibly-modified "args" struct.
In addition, the pre-wrapper may set some flags:
MayBlock -- only applicable when outcome==HandToKernel
PostOnFail -- only applicable when outcome==HandToKernel or Fail
* If the pre-outcome is HandToKernel, the syscall is duly handed
off to the kernel (perhaps involving some thread switchery, but
that's not important). This reduces the possible set of outcomes
to either Success(N) or Fail(N).
* The outcome (Success(N) or Fail(N)) is written back to the guest
register(s). This is platform specific:
x86: Success(N) ==> eax = N
Fail(N) ==> eax = -N
ditto amd64
ppc32: Success(N) ==> r3 = N, CR0.SO = 0
Fail(N) ==> r3 = N, CR0.SO = 1
Darwin:
x86: Success(N) ==> edx:eax = N, cc = 0
Fail(N) ==> edx:eax = N, cc = 1
s390x: Success(N) ==> r2 = N
Fail(N) ==> r2 = -N
* The post wrapper is called if:
- it exists, and
- outcome==Success or (outcome==Fail and PostOnFail is set)
The post wrapper is passed the adulterated syscall args (struct
"args"), and the syscall outcome (viz, Success(N) or Fail(N)).
There are several other complications, primarily to do with
syscalls getting interrupted, explained in comments in the code.
*/
/* CAVEATS for writing wrappers. It is important to follow these!
The macros defined in priv_types_n_macros.h are designed to help
decouple the wrapper logic from the actual representation of
syscall args/results, since these wrappers are designed to work on
multiple platforms.
Sometimes a PRE wrapper will complete the syscall itself, without
handing it to the kernel. It will use one of SET_STATUS_Success,
SET_STATUS_Failure or SET_STATUS_from_SysRes to set the return
value. It is critical to appreciate that use of the macro does not
immediately cause the underlying guest state to be updated -- that
is done by the driver logic in this file, when the wrapper returns.
As a result, PRE wrappers of the following form will malfunction:
PRE(fooble)
{
... do stuff ...
SET_STATUS_Somehow(...)
// do something that assumes guest state is up to date
}
In particular, direct or indirect calls to VG_(poll_signals) after
setting STATUS can cause the guest state to be read (in order to
build signal frames). Do not do this. If you want a signal poll
after the syscall goes through, do "*flags |= SfPollAfter" and the
driver logic will do it for you.
-----------
Another critical requirement following introduction of new address
space manager (JRS, 20050923):
In a situation where the mappedness of memory has changed, aspacem
should be notified BEFORE the tool. Hence the following is
correct:
Bool d = VG_(am_notify_munmap)(s->start, s->end+1 - s->start);
VG_TRACK( die_mem_munmap, s->start, s->end+1 - s->start );
if (d)
VG_(discard_translations)(s->start, s->end+1 - s->start);
whilst this is wrong:
VG_TRACK( die_mem_munmap, s->start, s->end+1 - s->start );
Bool d = VG_(am_notify_munmap)(s->start, s->end+1 - s->start);
if (d)
VG_(discard_translations)(s->start, s->end+1 - s->start);
The reason is that the tool may itself ask aspacem for more shadow
memory as a result of the VG_TRACK call. In such a situation it is
critical that aspacem's segment array is up to date -- hence the
need to notify aspacem first.
-----------
Also .. take care to call VG_(discard_translations) whenever
memory with execute permissions is unmapped.
*/
/* ---------------------------------------------------------------------
Do potentially blocking syscall for the client, and mess with
signal masks at the same time.
------------------------------------------------------------------ */
/* Perform a syscall on behalf of a client thread, using a specific
signal mask. On completion, the signal mask is set to restore_mask
(which presumably blocks almost everything). If a signal happens
during the syscall, the handler should call
VG_(fixup_guest_state_after_syscall_interrupted) to adjust the
thread's context to do the right thing.
The _WRK function is handwritten assembly, implemented per-platform
in coregrind/m_syswrap/syscall-$PLAT.S. It has some very magic
properties. See comments at the top of
VG_(fixup_guest_state_after_syscall_interrupted) below for details.
This function (these functions) are required to return zero in case
of success (even if the syscall itself failed), and nonzero if the
sigprocmask-swizzling calls failed. We don't actually care about
the failure values from sigprocmask, although most of the assembly
implementations do attempt to return that, using the convention
0 for success, or 0x8000 | error-code for failure.
*/
#if defined(VGO_linux)
extern
UWord ML_(do_syscall_for_client_WRK)( Word syscallno,
void* guest_state,
const vki_sigset_t *syscall_mask,
const vki_sigset_t *restore_mask,
Word sigsetSzB );
#elif defined(VGO_darwin)
extern
UWord ML_(do_syscall_for_client_unix_WRK)( Word syscallno,
void* guest_state,
const vki_sigset_t *syscall_mask,
const vki_sigset_t *restore_mask,
Word sigsetSzB ); /* unused */
extern
UWord ML_(do_syscall_for_client_mach_WRK)( Word syscallno,
void* guest_state,
const vki_sigset_t *syscall_mask,
const vki_sigset_t *restore_mask,
Word sigsetSzB ); /* unused */
extern
UWord ML_(do_syscall_for_client_mdep_WRK)( Word syscallno,
void* guest_state,
const vki_sigset_t *syscall_mask,
const vki_sigset_t *restore_mask,
Word sigsetSzB ); /* unused */
#else
# error "Unknown OS"
#endif
static
void do_syscall_for_client ( Int syscallno,
ThreadState* tst,
const vki_sigset_t* syscall_mask )
{
vki_sigset_t saved;
UWord err;
# if defined(VGO_linux)
err = ML_(do_syscall_for_client_WRK)(
syscallno, &tst->arch.vex,
syscall_mask, &saved, sizeof(vki_sigset_t)
);
# elif defined(VGO_darwin)
switch (VG_DARWIN_SYSNO_CLASS(syscallno)) {
case VG_DARWIN_SYSCALL_CLASS_UNIX:
err = ML_(do_syscall_for_client_unix_WRK)(
VG_DARWIN_SYSNO_FOR_KERNEL(syscallno), &tst->arch.vex,
syscall_mask, &saved, 0/*unused:sigsetSzB*/
);
break;
case VG_DARWIN_SYSCALL_CLASS_MACH:
err = ML_(do_syscall_for_client_mach_WRK)(
VG_DARWIN_SYSNO_FOR_KERNEL(syscallno), &tst->arch.vex,
syscall_mask, &saved, 0/*unused:sigsetSzB*/
);
break;
case VG_DARWIN_SYSCALL_CLASS_MDEP:
err = ML_(do_syscall_for_client_mdep_WRK)(
VG_DARWIN_SYSNO_FOR_KERNEL(syscallno), &tst->arch.vex,
syscall_mask, &saved, 0/*unused:sigsetSzB*/
);
break;
default:
vg_assert(0);
/*NOTREACHED*/
break;
}
# else
# error "Unknown OS"
# endif
vg_assert2(
err == 0,
"ML_(do_syscall_for_client_WRK): sigprocmask error %d",
(Int)(err & 0xFFF)
);
}
/* ---------------------------------------------------------------------
Impedance matchers and misc helpers
------------------------------------------------------------------ */
static
Bool eq_SyscallArgs ( SyscallArgs* a1, SyscallArgs* a2 )
{
return a1->sysno == a2->sysno
&& a1->arg1 == a2->arg1
&& a1->arg2 == a2->arg2
&& a1->arg3 == a2->arg3
&& a1->arg4 == a2->arg4
&& a1->arg5 == a2->arg5
&& a1->arg6 == a2->arg6
&& a1->arg7 == a2->arg7
&& a1->arg8 == a2->arg8;
}
static
Bool eq_SyscallStatus ( SyscallStatus* s1, SyscallStatus* s2 )
{
/* was: return s1->what == s2->what && sr_EQ( s1->sres, s2->sres ); */
if (s1->what == s2->what && sr_EQ( s1->sres, s2->sres ))
return True;
# if defined(VGO_darwin)
/* Darwin-specific debugging guff */
vg_assert(s1->what == s2->what);
VG_(printf)("eq_SyscallStatus:\n");
VG_(printf)(" {%lu %lu %u}\n", s1->sres._wLO, s1->sres._wHI, s1->sres._mode);
VG_(printf)(" {%lu %lu %u}\n", s2->sres._wLO, s2->sres._wHI, s2->sres._mode);
vg_assert(0);
# endif
return False;
}
/* Convert between SysRes and SyscallStatus, to the extent possible. */
static
SyscallStatus convert_SysRes_to_SyscallStatus ( SysRes res )
{
SyscallStatus status;
status.what = SsComplete;
status.sres = res;
return status;
}
/* Impedance matchers. These convert syscall arg or result data from
the platform-specific in-guest-state format to the canonical
formats, and back. */
static
void getSyscallArgsFromGuestState ( /*OUT*/SyscallArgs* canonical,
/*IN*/ VexGuestArchState* gst_vanilla,
/*IN*/ UInt trc )
{
#if defined(VGP_x86_linux)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
canonical->sysno = gst->guest_EAX;
canonical->arg1 = gst->guest_EBX;
canonical->arg2 = gst->guest_ECX;
canonical->arg3 = gst->guest_EDX;
canonical->arg4 = gst->guest_ESI;
canonical->arg5 = gst->guest_EDI;
canonical->arg6 = gst->guest_EBP;
canonical->arg7 = 0;
canonical->arg8 = 0;
#elif defined(VGP_amd64_linux)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
canonical->sysno = gst->guest_RAX;
canonical->arg1 = gst->guest_RDI;
canonical->arg2 = gst->guest_RSI;
canonical->arg3 = gst->guest_RDX;
canonical->arg4 = gst->guest_R10;
canonical->arg5 = gst->guest_R8;
canonical->arg6 = gst->guest_R9;
canonical->arg7 = 0;
canonical->arg8 = 0;
#elif defined(VGP_ppc32_linux)
VexGuestPPC32State* gst = (VexGuestPPC32State*)gst_vanilla;
canonical->sysno = gst->guest_GPR0;
canonical->arg1 = gst->guest_GPR3;
canonical->arg2 = gst->guest_GPR4;
canonical->arg3 = gst->guest_GPR5;
canonical->arg4 = gst->guest_GPR6;
canonical->arg5 = gst->guest_GPR7;
canonical->arg6 = gst->guest_GPR8;
canonical->arg7 = 0;
canonical->arg8 = 0;
#elif defined(VGP_ppc64_linux)
VexGuestPPC64State* gst = (VexGuestPPC64State*)gst_vanilla;
canonical->sysno = gst->guest_GPR0;
canonical->arg1 = gst->guest_GPR3;
canonical->arg2 = gst->guest_GPR4;
canonical->arg3 = gst->guest_GPR5;
canonical->arg4 = gst->guest_GPR6;
canonical->arg5 = gst->guest_GPR7;
canonical->arg6 = gst->guest_GPR8;
canonical->arg7 = 0;
canonical->arg8 = 0;
#elif defined(VGP_arm_linux)
VexGuestARMState* gst = (VexGuestARMState*)gst_vanilla;
canonical->sysno = gst->guest_R7;
canonical->arg1 = gst->guest_R0;
canonical->arg2 = gst->guest_R1;
canonical->arg3 = gst->guest_R2;
canonical->arg4 = gst->guest_R3;
canonical->arg5 = gst->guest_R4;
canonical->arg6 = gst->guest_R5;
canonical->arg7 = 0;
canonical->arg8 = 0;
#elif defined(VGP_arm64_linux)
VexGuestARM64State* gst = (VexGuestARM64State*)gst_vanilla;
canonical->sysno = gst->guest_X8;
canonical->arg1 = gst->guest_X0;
canonical->arg2 = gst->guest_X1;
canonical->arg3 = gst->guest_X2;
canonical->arg4 = gst->guest_X3;
canonical->arg5 = gst->guest_X4;
canonical->arg6 = gst->guest_X5;
canonical->arg7 = 0;
canonical->arg8 = 0;
#elif defined(VGP_mips32_linux)
VexGuestMIPS32State* gst = (VexGuestMIPS32State*)gst_vanilla;
canonical->sysno = gst->guest_r2; // v0
if (canonical->sysno == __NR_exit) {
canonical->arg1 = gst->guest_r4; // a0
canonical->arg2 = 0;
canonical->arg3 = 0;
canonical->arg4 = 0;
canonical->arg5 = 0;
canonical->arg6 = 0;
canonical->arg8 = 0;
} else if (canonical->sysno != __NR_syscall) {
canonical->arg1 = gst->guest_r4; // a0
canonical->arg2 = gst->guest_r5; // a1
canonical->arg3 = gst->guest_r6; // a2
canonical->arg4 = gst->guest_r7; // a3
canonical->arg5 = *((UInt*) (gst->guest_r29 + 16)); // 16(guest_SP/sp)
canonical->arg6 = *((UInt*) (gst->guest_r29 + 20)); // 20(sp)
canonical->arg8 = 0;
} else {
// Fixme hack handle syscall()
canonical->sysno = gst->guest_r4; // a0
canonical->arg1 = gst->guest_r5; // a1
canonical->arg2 = gst->guest_r6; // a2
canonical->arg3 = gst->guest_r7; // a3
canonical->arg4 = *((UInt*) (gst->guest_r29 + 16)); // 16(guest_SP/sp)
canonical->arg5 = *((UInt*) (gst->guest_r29 + 20)); // 20(guest_SP/sp)
canonical->arg6 = *((UInt*) (gst->guest_r29 + 24)); // 24(guest_SP/sp)
canonical->arg8 = __NR_syscall;
}
#elif defined(VGP_mips64_linux)
VexGuestMIPS64State* gst = (VexGuestMIPS64State*)gst_vanilla;
canonical->sysno = gst->guest_r2; // v0
canonical->arg1 = gst->guest_r4; // a0
canonical->arg2 = gst->guest_r5; // a1
canonical->arg3 = gst->guest_r6; // a2
canonical->arg4 = gst->guest_r7; // a3
canonical->arg5 = gst->guest_r8; // a4
canonical->arg6 = gst->guest_r9; // a5
#elif defined(VGP_x86_darwin)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
UWord *stack = (UWord *)gst->guest_ESP;
// GrP fixme hope syscalls aren't called with really shallow stacks...
canonical->sysno = gst->guest_EAX;
if (canonical->sysno != 0) {
// stack[0] is return address
canonical->arg1 = stack[1];
canonical->arg2 = stack[2];
canonical->arg3 = stack[3];
canonical->arg4 = stack[4];
canonical->arg5 = stack[5];
canonical->arg6 = stack[6];
canonical->arg7 = stack[7];
canonical->arg8 = stack[8];
} else {
// GrP fixme hack handle syscall()
// GrP fixme what about __syscall() ?
// stack[0] is return address
// DDD: the tool can't see that the params have been shifted! Can
// lead to incorrect checking, I think, because the PRRAn/PSARn
// macros will mention the pre-shifted args.
canonical->sysno = stack[1];
vg_assert(canonical->sysno != 0);
canonical->arg1 = stack[2];
canonical->arg2 = stack[3];
canonical->arg3 = stack[4];
canonical->arg4 = stack[5];
canonical->arg5 = stack[6];
canonical->arg6 = stack[7];
canonical->arg7 = stack[8];
canonical->arg8 = stack[9];
PRINT("SYSCALL[%d,?](%s) syscall(%s, ...); please stand by...\n",
VG_(getpid)(), /*tid,*/
VG_SYSNUM_STRING(0), VG_SYSNUM_STRING(canonical->sysno));
}
// Here we determine what kind of syscall it was by looking at the
// interrupt kind, and then encode the syscall number using the 64-bit
// encoding for Valgrind's internal use.
//
// DDD: Would it be better to stash the JMP kind into the Darwin
// thread state rather than passing in the trc?
switch (trc) {
case VEX_TRC_JMP_SYS_INT128:
// int $0x80 = Unix, 64-bit result
vg_assert(canonical->sysno >= 0);
canonical->sysno = VG_DARWIN_SYSCALL_CONSTRUCT_UNIX(canonical->sysno);
break;
case VEX_TRC_JMP_SYS_SYSENTER:
// syscall = Unix, 32-bit result
// OR Mach, 32-bit result
if (canonical->sysno >= 0) {
// GrP fixme hack: 0xffff == I386_SYSCALL_NUMBER_MASK
canonical->sysno = VG_DARWIN_SYSCALL_CONSTRUCT_UNIX(canonical->sysno
& 0xffff);
} else {
canonical->sysno = VG_DARWIN_SYSCALL_CONSTRUCT_MACH(-canonical->sysno);
}
break;
case VEX_TRC_JMP_SYS_INT129:
// int $0x81 = Mach, 32-bit result
vg_assert(canonical->sysno < 0);
canonical->sysno = VG_DARWIN_SYSCALL_CONSTRUCT_MACH(-canonical->sysno);
break;
case VEX_TRC_JMP_SYS_INT130:
// int $0x82 = mdep, 32-bit result
vg_assert(canonical->sysno >= 0);
canonical->sysno = VG_DARWIN_SYSCALL_CONSTRUCT_MDEP(canonical->sysno);
break;
default:
vg_assert(0);
break;
}
#elif defined(VGP_amd64_darwin)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
UWord *stack = (UWord *)gst->guest_RSP;
vg_assert(trc == VEX_TRC_JMP_SYS_SYSCALL);
// GrP fixme hope syscalls aren't called with really shallow stacks...
canonical->sysno = gst->guest_RAX;
if (canonical->sysno != __NR_syscall) {
// stack[0] is return address
canonical->arg1 = gst->guest_RDI;
canonical->arg2 = gst->guest_RSI;
canonical->arg3 = gst->guest_RDX;
canonical->arg4 = gst->guest_R10; // not rcx with syscall insn
canonical->arg5 = gst->guest_R8;
canonical->arg6 = gst->guest_R9;
canonical->arg7 = stack[1];
canonical->arg8 = stack[2];
} else {
// GrP fixme hack handle syscall()
// GrP fixme what about __syscall() ?
// stack[0] is return address
// DDD: the tool can't see that the params have been shifted! Can
// lead to incorrect checking, I think, because the PRRAn/PSARn
// macros will mention the pre-shifted args.
canonical->sysno = VG_DARWIN_SYSCALL_CONSTRUCT_UNIX(gst->guest_RDI);
vg_assert(canonical->sysno != __NR_syscall);
canonical->arg1 = gst->guest_RSI;
canonical->arg2 = gst->guest_RDX;
canonical->arg3 = gst->guest_R10; // not rcx with syscall insn
canonical->arg4 = gst->guest_R8;
canonical->arg5 = gst->guest_R9;
canonical->arg6 = stack[1];
canonical->arg7 = stack[2];
canonical->arg8 = stack[3];
PRINT("SYSCALL[%d,?](%s) syscall(%s, ...); please stand by...\n",
VG_(getpid)(), /*tid,*/
VG_SYSNUM_STRING(0), VG_SYSNUM_STRING(canonical->sysno));
}
// no canonical->sysno adjustment needed
#elif defined(VGP_s390x_linux)
VexGuestS390XState* gst = (VexGuestS390XState*)gst_vanilla;
canonical->sysno = gst->guest_SYSNO;
canonical->arg1 = gst->guest_r2;
canonical->arg2 = gst->guest_r3;
canonical->arg3 = gst->guest_r4;
canonical->arg4 = gst->guest_r5;
canonical->arg5 = gst->guest_r6;
canonical->arg6 = gst->guest_r7;
canonical->arg7 = 0;
canonical->arg8 = 0;
#else
# error "getSyscallArgsFromGuestState: unknown arch"
#endif
}
static
void putSyscallArgsIntoGuestState ( /*IN*/ SyscallArgs* canonical,
/*OUT*/VexGuestArchState* gst_vanilla )
{
#if defined(VGP_x86_linux)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
gst->guest_EAX = canonical->sysno;
gst->guest_EBX = canonical->arg1;
gst->guest_ECX = canonical->arg2;
gst->guest_EDX = canonical->arg3;
gst->guest_ESI = canonical->arg4;
gst->guest_EDI = canonical->arg5;
gst->guest_EBP = canonical->arg6;
#elif defined(VGP_amd64_linux)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
gst->guest_RAX = canonical->sysno;
gst->guest_RDI = canonical->arg1;
gst->guest_RSI = canonical->arg2;
gst->guest_RDX = canonical->arg3;
gst->guest_R10 = canonical->arg4;
gst->guest_R8 = canonical->arg5;
gst->guest_R9 = canonical->arg6;
#elif defined(VGP_ppc32_linux)
VexGuestPPC32State* gst = (VexGuestPPC32State*)gst_vanilla;
gst->guest_GPR0 = canonical->sysno;
gst->guest_GPR3 = canonical->arg1;
gst->guest_GPR4 = canonical->arg2;
gst->guest_GPR5 = canonical->arg3;
gst->guest_GPR6 = canonical->arg4;
gst->guest_GPR7 = canonical->arg5;
gst->guest_GPR8 = canonical->arg6;
#elif defined(VGP_ppc64_linux)
VexGuestPPC64State* gst = (VexGuestPPC64State*)gst_vanilla;
gst->guest_GPR0 = canonical->sysno;
gst->guest_GPR3 = canonical->arg1;
gst->guest_GPR4 = canonical->arg2;
gst->guest_GPR5 = canonical->arg3;
gst->guest_GPR6 = canonical->arg4;
gst->guest_GPR7 = canonical->arg5;
gst->guest_GPR8 = canonical->arg6;
#elif defined(VGP_arm_linux)
VexGuestARMState* gst = (VexGuestARMState*)gst_vanilla;
gst->guest_R7 = canonical->sysno;
gst->guest_R0 = canonical->arg1;
gst->guest_R1 = canonical->arg2;
gst->guest_R2 = canonical->arg3;
gst->guest_R3 = canonical->arg4;
gst->guest_R4 = canonical->arg5;
gst->guest_R5 = canonical->arg6;
#elif defined(VGP_arm64_linux)
VexGuestARM64State* gst = (VexGuestARM64State*)gst_vanilla;
gst->guest_X8 = canonical->sysno;
gst->guest_X0 = canonical->arg1;
gst->guest_X1 = canonical->arg2;
gst->guest_X2 = canonical->arg3;
gst->guest_X3 = canonical->arg4;
gst->guest_X4 = canonical->arg5;
gst->guest_X5 = canonical->arg6;
#elif defined(VGP_x86_darwin)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
UWord *stack = (UWord *)gst->guest_ESP;
gst->guest_EAX = VG_DARWIN_SYSNO_FOR_KERNEL(canonical->sysno);
// GrP fixme? gst->guest_TEMP_EFLAG_C = 0;
// stack[0] is return address
stack[1] = canonical->arg1;
stack[2] = canonical->arg2;
stack[3] = canonical->arg3;
stack[4] = canonical->arg4;
stack[5] = canonical->arg5;
stack[6] = canonical->arg6;
stack[7] = canonical->arg7;
stack[8] = canonical->arg8;
#elif defined(VGP_amd64_darwin)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
UWord *stack = (UWord *)gst->guest_RSP;
gst->guest_RAX = VG_DARWIN_SYSNO_FOR_KERNEL(canonical->sysno);
// GrP fixme? gst->guest_TEMP_EFLAG_C = 0;
// stack[0] is return address
gst->guest_RDI = canonical->arg1;
gst->guest_RSI = canonical->arg2;
gst->guest_RDX = canonical->arg3;
gst->guest_RCX = canonical->arg4;
gst->guest_R8 = canonical->arg5;
gst->guest_R9 = canonical->arg6;
stack[1] = canonical->arg7;
stack[2] = canonical->arg8;
#elif defined(VGP_s390x_linux)
VexGuestS390XState* gst = (VexGuestS390XState*)gst_vanilla;
gst->guest_SYSNO = canonical->sysno;
gst->guest_r2 = canonical->arg1;
gst->guest_r3 = canonical->arg2;
gst->guest_r4 = canonical->arg3;
gst->guest_r5 = canonical->arg4;
gst->guest_r6 = canonical->arg5;
gst->guest_r7 = canonical->arg6;
#elif defined(VGP_mips32_linux)
VexGuestMIPS32State* gst = (VexGuestMIPS32State*)gst_vanilla;
if (canonical->arg8 != __NR_syscall) {
gst->guest_r2 = canonical->sysno;
gst->guest_r4 = canonical->arg1;
gst->guest_r5 = canonical->arg2;
gst->guest_r6 = canonical->arg3;
gst->guest_r7 = canonical->arg4;
*((UInt*) (gst->guest_r29 + 16)) = canonical->arg5; // 16(guest_GPR29/sp)
*((UInt*) (gst->guest_r29 + 20)) = canonical->arg6; // 20(sp)
} else {
canonical->arg8 = 0;
gst->guest_r2 = __NR_syscall;
gst->guest_r4 = canonical->sysno;
gst->guest_r5 = canonical->arg1;
gst->guest_r6 = canonical->arg2;
gst->guest_r7 = canonical->arg3;
*((UInt*) (gst->guest_r29 + 16)) = canonical->arg4; // 16(guest_GPR29/sp)
*((UInt*) (gst->guest_r29 + 20)) = canonical->arg5; // 20(sp)
*((UInt*) (gst->guest_r29 + 24)) = canonical->arg6; // 24(sp)
}
#elif defined(VGP_mips64_linux)
VexGuestMIPS64State* gst = (VexGuestMIPS64State*)gst_vanilla;
gst->guest_r2 = canonical->sysno;
gst->guest_r4 = canonical->arg1;
gst->guest_r5 = canonical->arg2;
gst->guest_r6 = canonical->arg3;
gst->guest_r7 = canonical->arg4;
gst->guest_r8 = canonical->arg5;
gst->guest_r9 = canonical->arg6;
#else
# error "putSyscallArgsIntoGuestState: unknown arch"
#endif
}
static
void getSyscallStatusFromGuestState ( /*OUT*/SyscallStatus* canonical,
/*IN*/ VexGuestArchState* gst_vanilla )
{
# if defined(VGP_x86_linux)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
canonical->sres = VG_(mk_SysRes_x86_linux)( gst->guest_EAX );
canonical->what = SsComplete;
# elif defined(VGP_amd64_linux)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
canonical->sres = VG_(mk_SysRes_amd64_linux)( gst->guest_RAX );
canonical->what = SsComplete;
# elif defined(VGP_ppc32_linux)
VexGuestPPC32State* gst = (VexGuestPPC32State*)gst_vanilla;
UInt cr = LibVEX_GuestPPC32_get_CR( gst );
UInt cr0so = (cr >> 28) & 1;
canonical->sres = VG_(mk_SysRes_ppc32_linux)( gst->guest_GPR3, cr0so );
canonical->what = SsComplete;
# elif defined(VGP_ppc64_linux)
VexGuestPPC64State* gst = (VexGuestPPC64State*)gst_vanilla;
UInt cr = LibVEX_GuestPPC64_get_CR( gst );
UInt cr0so = (cr >> 28) & 1;
canonical->sres = VG_(mk_SysRes_ppc64_linux)( gst->guest_GPR3, cr0so );
canonical->what = SsComplete;
# elif defined(VGP_arm_linux)
VexGuestARMState* gst = (VexGuestARMState*)gst_vanilla;
canonical->sres = VG_(mk_SysRes_arm_linux)( gst->guest_R0 );
canonical->what = SsComplete;
# elif defined(VGP_arm64_linux)
VexGuestARM64State* gst = (VexGuestARM64State*)gst_vanilla;
canonical->sres = VG_(mk_SysRes_arm64_linux)( gst->guest_X0 );
canonical->what = SsComplete;
# elif defined(VGP_mips32_linux)
VexGuestMIPS32State* gst = (VexGuestMIPS32State*)gst_vanilla;
UInt v0 = gst->guest_r2; // v0
UInt v1 = gst->guest_r3; // v1
UInt a3 = gst->guest_r7; // a3
canonical->sres = VG_(mk_SysRes_mips32_linux)( v0, v1, a3 );
canonical->what = SsComplete;
# elif defined(VGP_mips64_linux)
VexGuestMIPS64State* gst = (VexGuestMIPS64State*)gst_vanilla;
ULong v0 = gst->guest_r2; // v0
ULong v1 = gst->guest_r3; // v1
ULong a3 = gst->guest_r7; // a3
canonical->sres = VG_(mk_SysRes_mips64_linux)(v0, v1, a3);
canonical->what = SsComplete;
# elif defined(VGP_x86_darwin)
/* duplicates logic in m_signals.VG_UCONTEXT_SYSCALL_SYSRES */
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
UInt carry = 1 & LibVEX_GuestX86_get_eflags(gst);
UInt err = 0;
UInt wLO = 0;
UInt wHI = 0;
switch (gst->guest_SC_CLASS) {
case VG_DARWIN_SYSCALL_CLASS_UNIX:
// int $0x80 = Unix, 64-bit result
err = carry;
wLO = gst->guest_EAX;
wHI = gst->guest_EDX;
break;
case VG_DARWIN_SYSCALL_CLASS_MACH:
// int $0x81 = Mach, 32-bit result
wLO = gst->guest_EAX;
break;
case VG_DARWIN_SYSCALL_CLASS_MDEP:
// int $0x82 = mdep, 32-bit result
wLO = gst->guest_EAX;
break;
default:
vg_assert(0);
break;
}
canonical->sres = VG_(mk_SysRes_x86_darwin)(
gst->guest_SC_CLASS, err ? True : False,
wHI, wLO
);
canonical->what = SsComplete;
# elif defined(VGP_amd64_darwin)
/* duplicates logic in m_signals.VG_UCONTEXT_SYSCALL_SYSRES */
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
ULong carry = 1 & LibVEX_GuestAMD64_get_rflags(gst);
ULong err = 0;
ULong wLO = 0;
ULong wHI = 0;
switch (gst->guest_SC_CLASS) {
case VG_DARWIN_SYSCALL_CLASS_UNIX:
// syscall = Unix, 128-bit result
err = carry;
wLO = gst->guest_RAX;
wHI = gst->guest_RDX;
break;
case VG_DARWIN_SYSCALL_CLASS_MACH:
// syscall = Mach, 64-bit result
wLO = gst->guest_RAX;
break;
case VG_DARWIN_SYSCALL_CLASS_MDEP:
// syscall = mdep, 64-bit result
wLO = gst->guest_RAX;
break;
default:
vg_assert(0);
break;
}
canonical->sres = VG_(mk_SysRes_amd64_darwin)(
gst->guest_SC_CLASS, err ? True : False,
wHI, wLO
);
canonical->what = SsComplete;
# elif defined(VGP_s390x_linux)
VexGuestS390XState* gst = (VexGuestS390XState*)gst_vanilla;
canonical->sres = VG_(mk_SysRes_s390x_linux)( gst->guest_r2 );
canonical->what = SsComplete;
# else
# error "getSyscallStatusFromGuestState: unknown arch"
# endif
}
static
void putSyscallStatusIntoGuestState ( /*IN*/ ThreadId tid,
/*IN*/ SyscallStatus* canonical,
/*OUT*/VexGuestArchState* gst_vanilla )
{
# if defined(VGP_x86_linux)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
/* This isn't exactly right, in that really a Failure with res
not in the range 1 .. 4095 is unrepresentable in the
Linux-x86 scheme. Oh well. */
gst->guest_EAX = - (Int)sr_Err(canonical->sres);
} else {
gst->guest_EAX = sr_Res(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_x86_EAX, sizeof(UWord) );
# elif defined(VGP_amd64_linux)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
/* This isn't exactly right, in that really a Failure with res
not in the range 1 .. 4095 is unrepresentable in the
Linux-amd64 scheme. Oh well. */
gst->guest_RAX = - (Long)sr_Err(canonical->sres);
} else {
gst->guest_RAX = sr_Res(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_amd64_RAX, sizeof(UWord) );
# elif defined(VGP_ppc32_linux)
VexGuestPPC32State* gst = (VexGuestPPC32State*)gst_vanilla;
UInt old_cr = LibVEX_GuestPPC32_get_CR(gst);
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
/* set CR0.SO */
LibVEX_GuestPPC32_put_CR( old_cr | (1<<28), gst );
gst->guest_GPR3 = sr_Err(canonical->sres);
} else {
/* clear CR0.SO */
LibVEX_GuestPPC32_put_CR( old_cr & ~(1<<28), gst );
gst->guest_GPR3 = sr_Res(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_ppc32_GPR3, sizeof(UWord) );
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_ppc32_CR0_0, sizeof(UChar) );
# elif defined(VGP_ppc64_linux)
VexGuestPPC64State* gst = (VexGuestPPC64State*)gst_vanilla;
UInt old_cr = LibVEX_GuestPPC64_get_CR(gst);
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
/* set CR0.SO */
LibVEX_GuestPPC64_put_CR( old_cr | (1<<28), gst );
gst->guest_GPR3 = sr_Err(canonical->sres);
} else {
/* clear CR0.SO */
LibVEX_GuestPPC64_put_CR( old_cr & ~(1<<28), gst );
gst->guest_GPR3 = sr_Res(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_ppc64_GPR3, sizeof(UWord) );
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_ppc64_CR0_0, sizeof(UChar) );
# elif defined(VGP_arm_linux)
VexGuestARMState* gst = (VexGuestARMState*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
/* This isn't exactly right, in that really a Failure with res
not in the range 1 .. 4095 is unrepresentable in the
Linux-arm scheme. Oh well. */
gst->guest_R0 = - (Int)sr_Err(canonical->sres);
} else {
gst->guest_R0 = sr_Res(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_arm_R0, sizeof(UWord) );
# elif defined(VGP_arm64_linux)
VexGuestARM64State* gst = (VexGuestARM64State*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
/* This isn't exactly right, in that really a Failure with res
not in the range 1 .. 4095 is unrepresentable in the
Linux-arm64 scheme. Oh well. */
gst->guest_X0 = - (Long)sr_Err(canonical->sres);
} else {
gst->guest_X0 = sr_Res(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_arm64_X0, sizeof(UWord) );
#elif defined(VGP_x86_darwin)
VexGuestX86State* gst = (VexGuestX86State*)gst_vanilla;
SysRes sres = canonical->sres;
vg_assert(canonical->what == SsComplete);
/* Unfortunately here we have to break abstraction and look
directly inside 'res', in order to decide what to do. */
switch (sres._mode) {
case SysRes_MACH: // int $0x81 = Mach, 32-bit result
case SysRes_MDEP: // int $0x82 = mdep, 32-bit result
gst->guest_EAX = sres._wLO;
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_x86_EAX, sizeof(UInt) );
break;
case SysRes_UNIX_OK: // int $0x80 = Unix, 64-bit result
case SysRes_UNIX_ERR: // int $0x80 = Unix, 64-bit error
gst->guest_EAX = sres._wLO;
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_x86_EAX, sizeof(UInt) );
gst->guest_EDX = sres._wHI;
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_x86_EDX, sizeof(UInt) );
LibVEX_GuestX86_put_eflag_c( sres._mode==SysRes_UNIX_ERR ? 1 : 0,
gst );
// GrP fixme sets defined for entire eflags, not just bit c
// DDD: this breaks exp-ptrcheck.
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
offsetof(VexGuestX86State, guest_CC_DEP1), sizeof(UInt) );
break;
default:
vg_assert(0);
break;
}
#elif defined(VGP_amd64_darwin)
VexGuestAMD64State* gst = (VexGuestAMD64State*)gst_vanilla;
SysRes sres = canonical->sres;
vg_assert(canonical->what == SsComplete);
/* Unfortunately here we have to break abstraction and look
directly inside 'res', in order to decide what to do. */
switch (sres._mode) {
case SysRes_MACH: // syscall = Mach, 64-bit result
case SysRes_MDEP: // syscall = mdep, 64-bit result
gst->guest_RAX = sres._wLO;
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_amd64_RAX, sizeof(ULong) );
break;
case SysRes_UNIX_OK: // syscall = Unix, 128-bit result
case SysRes_UNIX_ERR: // syscall = Unix, 128-bit error
gst->guest_RAX = sres._wLO;
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_amd64_RAX, sizeof(ULong) );
gst->guest_RDX = sres._wHI;
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_amd64_RDX, sizeof(ULong) );
LibVEX_GuestAMD64_put_rflag_c( sres._mode==SysRes_UNIX_ERR ? 1 : 0,
gst );
// GrP fixme sets defined for entire rflags, not just bit c
// DDD: this breaks exp-ptrcheck.
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
offsetof(VexGuestAMD64State, guest_CC_DEP1), sizeof(ULong) );
break;
default:
vg_assert(0);
break;
}
# elif defined(VGP_s390x_linux)
VexGuestS390XState* gst = (VexGuestS390XState*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
gst->guest_r2 = - (Long)sr_Err(canonical->sres);
} else {
gst->guest_r2 = sr_Res(canonical->sres);
}
# elif defined(VGP_mips32_linux)
VexGuestMIPS32State* gst = (VexGuestMIPS32State*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
gst->guest_r2 = (Int)sr_Err(canonical->sres);
gst->guest_r7 = (Int)sr_Err(canonical->sres);
} else {
gst->guest_r2 = sr_Res(canonical->sres);
gst->guest_r3 = sr_ResEx(canonical->sres);
gst->guest_r7 = (Int)sr_Err(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_mips32_r2, sizeof(UWord) );
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_mips32_r3, sizeof(UWord) );
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_mips32_r7, sizeof(UWord) );
# elif defined(VGP_mips64_linux)
VexGuestMIPS64State* gst = (VexGuestMIPS64State*)gst_vanilla;
vg_assert(canonical->what == SsComplete);
if (sr_isError(canonical->sres)) {
gst->guest_r2 = (Int)sr_Err(canonical->sres);
gst->guest_r7 = (Int)sr_Err(canonical->sres);
} else {
gst->guest_r2 = sr_Res(canonical->sres);
gst->guest_r3 = sr_ResEx(canonical->sres);
gst->guest_r7 = (Int)sr_Err(canonical->sres);
}
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_mips64_r2, sizeof(UWord) );
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_mips64_r3, sizeof(UWord) );
VG_TRACK( post_reg_write, Vg_CoreSysCall, tid,
OFFSET_mips64_r7, sizeof(UWord) );
# else
# error "putSyscallStatusIntoGuestState: unknown arch"
# endif
}
/* Tell me the offsets in the guest state of the syscall params, so
that the scalar argument checkers don't have to have this info
hardwired. */
static
void getSyscallArgLayout ( /*OUT*/SyscallArgLayout* layout )
{
VG_(bzero_inline)(layout, sizeof(*layout));
#if defined(VGP_x86_linux)
layout->o_sysno = OFFSET_x86_EAX;
layout->o_arg1 = OFFSET_x86_EBX;
layout->o_arg2 = OFFSET_x86_ECX;
layout->o_arg3 = OFFSET_x86_EDX;
layout->o_arg4 = OFFSET_x86_ESI;
layout->o_arg5 = OFFSET_x86_EDI;
layout->o_arg6 = OFFSET_x86_EBP;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_amd64_linux)
layout->o_sysno = OFFSET_amd64_RAX;
layout->o_arg1 = OFFSET_amd64_RDI;
layout->o_arg2 = OFFSET_amd64_RSI;
layout->o_arg3 = OFFSET_amd64_RDX;
layout->o_arg4 = OFFSET_amd64_R10;
layout->o_arg5 = OFFSET_amd64_R8;
layout->o_arg6 = OFFSET_amd64_R9;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_ppc32_linux)
layout->o_sysno = OFFSET_ppc32_GPR0;
layout->o_arg1 = OFFSET_ppc32_GPR3;
layout->o_arg2 = OFFSET_ppc32_GPR4;
layout->o_arg3 = OFFSET_ppc32_GPR5;
layout->o_arg4 = OFFSET_ppc32_GPR6;
layout->o_arg5 = OFFSET_ppc32_GPR7;
layout->o_arg6 = OFFSET_ppc32_GPR8;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_ppc64_linux)
layout->o_sysno = OFFSET_ppc64_GPR0;
layout->o_arg1 = OFFSET_ppc64_GPR3;
layout->o_arg2 = OFFSET_ppc64_GPR4;
layout->o_arg3 = OFFSET_ppc64_GPR5;
layout->o_arg4 = OFFSET_ppc64_GPR6;
layout->o_arg5 = OFFSET_ppc64_GPR7;
layout->o_arg6 = OFFSET_ppc64_GPR8;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_arm_linux)
layout->o_sysno = OFFSET_arm_R7;
layout->o_arg1 = OFFSET_arm_R0;
layout->o_arg2 = OFFSET_arm_R1;
layout->o_arg3 = OFFSET_arm_R2;
layout->o_arg4 = OFFSET_arm_R3;
layout->o_arg5 = OFFSET_arm_R4;
layout->o_arg6 = OFFSET_arm_R5;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_arm64_linux)
layout->o_sysno = OFFSET_arm64_X8;
layout->o_arg1 = OFFSET_arm64_X0;
layout->o_arg2 = OFFSET_arm64_X1;
layout->o_arg3 = OFFSET_arm64_X2;
layout->o_arg4 = OFFSET_arm64_X3;
layout->o_arg5 = OFFSET_arm64_X4;
layout->o_arg6 = OFFSET_arm64_X5;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_mips32_linux)
layout->o_sysno = OFFSET_mips32_r2;
layout->o_arg1 = OFFSET_mips32_r4;
layout->o_arg2 = OFFSET_mips32_r5;
layout->o_arg3 = OFFSET_mips32_r6;
layout->o_arg4 = OFFSET_mips32_r7;
layout->s_arg5 = sizeof(UWord) * 4;
layout->s_arg6 = sizeof(UWord) * 5;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_mips64_linux)
layout->o_sysno = OFFSET_mips64_r2;
layout->o_arg1 = OFFSET_mips64_r4;
layout->o_arg2 = OFFSET_mips64_r5;
layout->o_arg3 = OFFSET_mips64_r6;
layout->o_arg4 = OFFSET_mips64_r7;
layout->o_arg5 = OFFSET_mips64_r8;
layout->o_arg6 = OFFSET_mips64_r9;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#elif defined(VGP_x86_darwin)
layout->o_sysno = OFFSET_x86_EAX;
// syscall parameters are on stack in C convention
layout->s_arg1 = sizeof(UWord) * 1;
layout->s_arg2 = sizeof(UWord) * 2;
layout->s_arg3 = sizeof(UWord) * 3;
layout->s_arg4 = sizeof(UWord) * 4;
layout->s_arg5 = sizeof(UWord) * 5;
layout->s_arg6 = sizeof(UWord) * 6;
layout->s_arg7 = sizeof(UWord) * 7;
layout->s_arg8 = sizeof(UWord) * 8;
#elif defined(VGP_amd64_darwin)
layout->o_sysno = OFFSET_amd64_RAX;
layout->o_arg1 = OFFSET_amd64_RDI;
layout->o_arg2 = OFFSET_amd64_RSI;
layout->o_arg3 = OFFSET_amd64_RDX;
layout->o_arg4 = OFFSET_amd64_RCX;
layout->o_arg5 = OFFSET_amd64_R8;
layout->o_arg6 = OFFSET_amd64_R9;
layout->s_arg7 = sizeof(UWord) * 1;
layout->s_arg8 = sizeof(UWord) * 2;
#elif defined(VGP_s390x_linux)
layout->o_sysno = OFFSET_s390x_SYSNO;
layout->o_arg1 = OFFSET_s390x_r2;
layout->o_arg2 = OFFSET_s390x_r3;
layout->o_arg3 = OFFSET_s390x_r4;
layout->o_arg4 = OFFSET_s390x_r5;
layout->o_arg5 = OFFSET_s390x_r6;
layout->o_arg6 = OFFSET_s390x_r7;
layout->uu_arg7 = -1; /* impossible value */
layout->uu_arg8 = -1; /* impossible value */
#else
# error "getSyscallLayout: unknown arch"
#endif
}
/* ---------------------------------------------------------------------
The main driver logic
------------------------------------------------------------------ */
/* Finding the handlers for a given syscall, or faking up one
when no handler is found. */
static
void bad_before ( ThreadId tid,
SyscallArgLayout* layout,
/*MOD*/SyscallArgs* args,
/*OUT*/SyscallStatus* status,
/*OUT*/UWord* flags )
{
VG_(dmsg)("WARNING: unhandled syscall: %s\n",
VG_SYSNUM_STRING_EXTRA(args->sysno));
if (VG_(clo_verbosity) > 1) {
VG_(get_and_pp_StackTrace)(tid, VG_(clo_backtrace_size));
}
VG_(dmsg)("You may be able to write your own handler.\n");
VG_(dmsg)("Read the file README_MISSING_SYSCALL_OR_IOCTL.\n");
VG_(dmsg)("Nevertheless we consider this a bug. Please report\n");
VG_(dmsg)("it at http://valgrind.org/support/bug_reports.html.\n");
SET_STATUS_Failure(VKI_ENOSYS);
}
static SyscallTableEntry bad_sys =
{ bad_before, NULL };
static const SyscallTableEntry* get_syscall_entry ( Int syscallno )
{
const SyscallTableEntry* sys = NULL;
# if defined(VGO_linux)
sys = ML_(get_linux_syscall_entry)( syscallno );
# elif defined(VGO_darwin)
Int idx = VG_DARWIN_SYSNO_INDEX(syscallno);
switch (VG_DARWIN_SYSNO_CLASS(syscallno)) {
case VG_DARWIN_SYSCALL_CLASS_UNIX:
if (idx >= 0 && idx < ML_(syscall_table_size) &&
ML_(syscall_table)[idx].before != NULL)
sys = &ML_(syscall_table)[idx];
break;
case VG_DARWIN_SYSCALL_CLASS_MACH:
if (idx >= 0 && idx < ML_(mach_trap_table_size) &&
ML_(mach_trap_table)[idx].before != NULL)
sys = &ML_(mach_trap_table)[idx];
break;
case VG_DARWIN_SYSCALL_CLASS_MDEP:
if (idx >= 0 && idx < ML_(mdep_trap_table_size) &&
ML_(mdep_trap_table)[idx].before != NULL)
sys = &ML_(mdep_trap_table)[idx];
break;
default:
vg_assert(0);
break;
}
# else
# error Unknown OS
# endif
return sys == NULL ? &bad_sys : sys;
}
/* Add and remove signals from mask so that we end up telling the
kernel the state we actually want rather than what the client
wants. */
static void sanitize_client_sigmask(vki_sigset_t *mask)
{
VG_(sigdelset)(mask, VKI_SIGKILL);
VG_(sigdelset)(mask, VKI_SIGSTOP);
VG_(sigdelset)(mask, VG_SIGVGKILL); /* never block */
}
typedef
struct {
SyscallArgs orig_args;
SyscallArgs args;
SyscallStatus status;
UWord flags;
}
SyscallInfo;
SyscallInfo syscallInfo[VG_N_THREADS];
/* The scheduler needs to be able to zero out these records after a
fork, hence this is exported from m_syswrap. */
void VG_(clear_syscallInfo) ( Int tid )
{
vg_assert(tid >= 0 && tid < VG_N_THREADS);
VG_(memset)( & syscallInfo[tid], 0, sizeof( syscallInfo[tid] ));
syscallInfo[tid].status.what = SsIdle;
}
static void ensure_initialised ( void )
{
Int i;
static Bool init_done = False;
if (init_done)
return;
init_done = True;
for (i = 0; i < VG_N_THREADS; i++) {
VG_(clear_syscallInfo)( i );
}
}
/* --- This is the main function of this file. --- */
void VG_(client_syscall) ( ThreadId tid, UInt trc )
{
Word sysno;
ThreadState* tst;
const SyscallTableEntry* ent;
SyscallArgLayout layout;
SyscallInfo* sci;
ensure_initialised();
vg_assert(VG_(is_valid_tid)(tid));
vg_assert(tid >= 1 && tid < VG_N_THREADS);
vg_assert(VG_(is_running_thread)(tid));
tst = VG_(get_ThreadState)(tid);
/* BEGIN ensure root thread's stack is suitably mapped */
/* In some rare circumstances, we may do the syscall without the
bottom page of the stack being mapped, because the stack pointer
was moved down just a few instructions before the syscall
instruction, and there have been no memory references since
then, that would cause a call to VG_(extend_stack) to have
happened.
In native execution that's OK: the kernel automagically extends
the stack's mapped area down to cover the stack pointer (or sp -
redzone, really). In simulated normal execution that's OK too,
since any signals we get from accessing below the mapped area of
the (guest's) stack lead us to VG_(extend_stack), where we
simulate the kernel's stack extension logic. But that leaves
the problem of entering a syscall with the SP unmapped. Because
the kernel doesn't know that the segment immediately above SP is
supposed to be a grow-down segment, it causes the syscall to
fail, and thereby causes a divergence between native behaviour
(syscall succeeds) and simulated behaviour (syscall fails).
This is quite a rare failure mode. It has only been seen
affecting calls to sys_readlink on amd64-linux, and even then it
requires a certain code sequence around the syscall to trigger
it. Here is one:
extern int my_readlink ( const char* path );
asm(
".text\n"
".globl my_readlink\n"
"my_readlink:\n"
"\tsubq $0x1008,%rsp\n"
"\tmovq %rdi,%rdi\n" // path is in rdi
"\tmovq %rsp,%rsi\n" // &buf[0] -> rsi
"\tmovl $0x1000,%edx\n" // sizeof(buf) in rdx
"\tmovl $"__NR_READLINK",%eax\n" // syscall number
"\tsyscall\n"
"\taddq $0x1008,%rsp\n"
"\tret\n"
".previous\n"
);
For more details, see bug #156404
(https://bugs.kde.org/show_bug.cgi?id=156404).
The fix is actually very simple. We simply need to call
VG_(extend_stack) for this thread, handing it the lowest
possible valid address for stack (sp - redzone), to ensure the
pages all the way down to that address, are mapped. Because
this is a potentially expensive and frequent operation, we
filter in two ways:
First, only the main thread (tid=1) has a growdown stack. So
ignore all others. It is conceivable, although highly unlikely,
that the main thread exits, and later another thread is
allocated tid=1, but that's harmless, I believe;
VG_(extend_stack) will do nothing when applied to a non-root
thread.
Secondly, first call VG_(am_find_nsegment) directly, to see if
the page holding (sp - redzone) is mapped correctly. If so, do
nothing. This is almost always the case. VG_(extend_stack)
calls VG_(am_find_nsegment) twice, so this optimisation -- and
that's all it is -- more or less halves the number of calls to
VG_(am_find_nsegment) required.
TODO: the test "seg->kind == SkAnonC" is really inadequate,
because although it tests whether the segment is mapped
_somehow_, it doesn't check that it has the right permissions
(r,w, maybe x) ? We could test that here, but it will also be
necessary to fix the corresponding test in VG_(extend_stack).
All this guff is of course Linux-specific. Hence the ifdef.
*/
# if defined(VGO_linux)
if (tid == 1/*ROOT THREAD*/) {
Addr stackMin = VG_(get_SP)(tid) - VG_STACK_REDZONE_SZB;
NSegment const* seg = VG_(am_find_nsegment)(stackMin);
if (seg && seg->kind == SkAnonC) {
/* stackMin is already mapped. Nothing to do. */
} else {
(void)VG_(extend_stack)( stackMin,
tst->client_stack_szB );
}
}
# endif
/* END ensure root thread's stack is suitably mapped */
/* First off, get the syscall args and number. This is a
platform-dependent action. */
sci = & syscallInfo[tid];
vg_assert(sci->status.what == SsIdle);
getSyscallArgsFromGuestState( &sci->orig_args, &tst->arch.vex, trc );
/* Copy .orig_args to .args. The pre-handler may modify .args, but
we want to keep the originals too, just in case. */
sci->args = sci->orig_args;
/* Save the syscall number in the thread state in case the syscall
is interrupted by a signal. */
sysno = sci->orig_args.sysno;
/* It's sometimes useful, as a crude debugging hack, to get a
stack trace at each (or selected) syscalls. */
if (0 && sysno == __NR_ioctl) {
VG_(umsg)("\nioctl:\n");
VG_(get_and_pp_StackTrace)(tid, 10);
VG_(umsg)("\n");
}
# if defined(VGO_darwin)
/* Record syscall class. But why? Because the syscall might be
interrupted by a signal, and in the signal handler (which will
be m_signals.async_signalhandler) we will need to build a SysRes
reflecting the syscall return result. In order to do that we
need to know the syscall class. Hence stash it in the guest
state of this thread. This madness is not needed on Linux
because it only has a single syscall return convention and so
there is no ambiguity involved in converting the post-signal
machine state into a SysRes. */
tst->arch.vex.guest_SC_CLASS = VG_DARWIN_SYSNO_CLASS(sysno);
# endif
/* The default what-to-do-next thing is hand the syscall to the
kernel, so we pre-set that here. Set .sres to something
harmless looking (is irrelevant because .what is not
SsComplete.) */
sci->status.what = SsHandToKernel;
sci->status.sres = VG_(mk_SysRes_Error)(0);
sci->flags = 0;
/* Fetch the syscall's handlers. If no handlers exist for this
syscall, we are given dummy handlers which force an immediate
return with ENOSYS. */
ent = get_syscall_entry(sysno);
/* Fetch the layout information, which tells us where in the guest
state the syscall args reside. This is a platform-dependent
action. This info is needed so that the scalar syscall argument
checks (PRE_REG_READ calls) know which bits of the guest state
they need to inspect. */
getSyscallArgLayout( &layout );
/* Make sure the tmp signal mask matches the real signal mask;
sigsuspend may change this. */
vg_assert(VG_(iseqsigset)(&tst->sig_mask, &tst->tmp_sig_mask));
/* Right, we're finally ready to Party. Call the pre-handler and
see what we get back. At this point:
sci->status.what is Unset (we don't know yet).
sci->orig_args contains the original args.
sci->args is the same as sci->orig_args.
sci->flags is zero.
*/
PRINT("SYSCALL[%d,%d](%s) ",
VG_(getpid)(), tid, VG_SYSNUM_STRING(sysno));
/* Do any pre-syscall actions */
if (VG_(needs).syscall_wrapper) {
UWord tmpv[8];
tmpv[0] = sci->orig_args.arg1;
tmpv[1] = sci->orig_args.arg2;
tmpv[2] = sci->orig_args.arg3;
tmpv[3] = sci->orig_args.arg4;
tmpv[4] = sci->orig_args.arg5;
tmpv[5] = sci->orig_args.arg6;
tmpv[6] = sci->orig_args.arg7;
tmpv[7] = sci->orig_args.arg8;
VG_TDICT_CALL(tool_pre_syscall, tid, sysno,
&tmpv[0], sizeof(tmpv)/sizeof(tmpv[0]));
}
vg_assert(ent);
vg_assert(ent->before);
(ent->before)( tid,
&layout,
&sci->args, &sci->status, &sci->flags );
/* The pre-handler may have modified:
sci->args
sci->status
sci->flags
All else remains unchanged.
Although the args may be modified, pre handlers are not allowed
to change the syscall number.
*/
/* Now we proceed according to what the pre-handler decided. */
vg_assert(sci->status.what == SsHandToKernel
|| sci->status.what == SsComplete);
vg_assert(sci->args.sysno == sci->orig_args.sysno);
if (sci->status.what == SsComplete && !sr_isError(sci->status.sres)) {
/* The pre-handler completed the syscall itself, declaring
success. */
if (sci->flags & SfNoWriteResult) {
PRINT(" --> [pre-success] NoWriteResult");
} else {
PRINT(" --> [pre-success] Success(0x%llx:0x%llx)",
(ULong)sr_ResHI(sci->status.sres),
(ULong)sr_Res(sci->status.sres));
}
/* In this case the allowable flags are to ask for a signal-poll
and/or a yield after the call. Changing the args isn't
allowed. */
vg_assert(0 == (sci->flags
& ~(SfPollAfter | SfYieldAfter | SfNoWriteResult)));
vg_assert(eq_SyscallArgs(&sci->args, &sci->orig_args));
}
else
if (sci->status.what == SsComplete && sr_isError(sci->status.sres)) {
/* The pre-handler decided to fail syscall itself. */
PRINT(" --> [pre-fail] Failure(0x%llx)", (ULong)sr_Err(sci->status.sres));
/* In this case, the pre-handler is also allowed to ask for the
post-handler to be run anyway. Changing the args is not
allowed. */
vg_assert(0 == (sci->flags & ~(SfMayBlock | SfPostOnFail | SfPollAfter)));
vg_assert(eq_SyscallArgs(&sci->args, &sci->orig_args));
}
else
if (sci->status.what != SsHandToKernel) {
/* huh?! */
vg_assert(0);
}
else /* (sci->status.what == HandToKernel) */ {
/* Ok, this is the usual case -- and the complicated one. There
are two subcases: sync and async. async is the general case
and is to be used when there is any possibility that the
syscall might block [a fact that the pre-handler must tell us
via the sci->flags field.] Because the tidying-away /
context-switch overhead of the async case could be large, if
we are sure that the syscall will not block, we fast-track it
by doing it directly in this thread, which is a lot
simpler. */
/* Check that the given flags are allowable: MayBlock, PollAfter
and PostOnFail are ok. */
vg_assert(0 == (sci->flags & ~(SfMayBlock | SfPostOnFail | SfPollAfter)));
if (sci->flags & SfMayBlock) {
/* Syscall may block, so run it asynchronously */
vki_sigset_t mask;
PRINT(" --> [async] ... \n");
mask = tst->sig_mask;
sanitize_client_sigmask(&mask);
/* Gack. More impedance matching. Copy the possibly
modified syscall args back into the guest state. */
/* JRS 2009-Mar-16: if the syscall args are possibly modified,
then this assertion is senseless:
vg_assert(eq_SyscallArgs(&sci->args, &sci->orig_args));
The case that exposed it was sys_posix_spawn on Darwin,
which heavily modifies its arguments but then lets the call
go through anyway, with SfToBlock set, hence we end up here. */
putSyscallArgsIntoGuestState( &sci->args, &tst->arch.vex );
/* Drop the bigLock */
VG_(release_BigLock)(tid, VgTs_WaitSys, "VG_(client_syscall)[async]");
/* Urr. We're now in a race against other threads trying to
acquire the bigLock. I guess that doesn't matter provided
that do_syscall_for_client only touches thread-local
state. */
/* Do the call, which operates directly on the guest state,
not on our abstracted copies of the args/result. */
do_syscall_for_client(sysno, tst, &mask);
/* do_syscall_for_client may not return if the syscall was
interrupted by a signal. In that case, flow of control is
first to m_signals.async_sighandler, which calls
VG_(fixup_guest_state_after_syscall_interrupted), which
fixes up the guest state, and possibly calls
VG_(post_syscall). Once that's done, control drops back
to the scheduler. */
/* Darwin: do_syscall_for_client may not return if the
syscall was workq_ops(WQOPS_THREAD_RETURN) and the kernel
responded by starting the thread at wqthread_hijack(reuse=1)
(to run another workqueue item). In that case, wqthread_hijack
calls ML_(wqthread_continue), which is similar to
VG_(fixup_guest_state_after_syscall_interrupted). */
/* Reacquire the lock */
VG_(acquire_BigLock)(tid, "VG_(client_syscall)[async]");
/* Even more impedance matching. Extract the syscall status
from the guest state. */
getSyscallStatusFromGuestState( &sci->status, &tst->arch.vex );
vg_assert(sci->status.what == SsComplete);
/* Be decorative, if required. */
if (VG_(clo_trace_syscalls)) {
Bool failed = sr_isError(sci->status.sres);
if (failed) {
PRINT("SYSCALL[%d,%d](%s) ... [async] --> Failure(0x%llx)",
VG_(getpid)(), tid, VG_SYSNUM_STRING(sysno),
(ULong)sr_Err(sci->status.sres));
} else {
PRINT("SYSCALL[%d,%d](%s) ... [async] --> "
"Success(0x%llx:0x%llx)",
VG_(getpid)(), tid, VG_SYSNUM_STRING(sysno),
(ULong)sr_ResHI(sci->status.sres),
(ULong)sr_Res(sci->status.sres) );
}
}
} else {
/* run the syscall directly */
/* The pre-handler may have modified the syscall args, but
since we're passing values in ->args directly to the
kernel, there's no point in flushing them back to the
guest state. Indeed doing so could be construed as
incorrect. */
SysRes sres
= VG_(do_syscall)(sysno, sci->args.arg1, sci->args.arg2,
sci->args.arg3, sci->args.arg4,
sci->args.arg5, sci->args.arg6,
sci->args.arg7, sci->args.arg8 );
sci->status = convert_SysRes_to_SyscallStatus(sres);
/* Be decorative, if required. */
if (VG_(clo_trace_syscalls)) {
Bool failed = sr_isError(sci->status.sres);
if (failed) {
PRINT("[sync] --> Failure(0x%llx)",
(ULong)sr_Err(sci->status.sres) );
} else {
PRINT("[sync] --> Success(0x%llx:0x%llx)",
(ULong)sr_ResHI(sci->status.sres),
(ULong)sr_Res(sci->status.sres) );
}
}
}
}
vg_assert(sci->status.what == SsComplete);
vg_assert(VG_(is_running_thread)(tid));
/* Dump the syscall result back in the guest state. This is
a platform-specific action. */
if (!(sci->flags & SfNoWriteResult))
putSyscallStatusIntoGuestState( tid, &sci->status, &tst->arch.vex );
/* Situation now:
- the guest state is now correctly modified following the syscall
- modified args, original args and syscall status are still
available in the syscallInfo[] entry for this syscall.
Now go on to do the post-syscall actions (read on down ..)
*/
PRINT(" ");
VG_(post_syscall)(tid);
PRINT("\n");
}
/* Perform post syscall actions. The expected state on entry is
precisely as at the end of VG_(client_syscall), that is:
- guest state up to date following the syscall
- modified args, original args and syscall status are still
available in the syscallInfo[] entry for this syscall.
- syscall status matches what's in the guest state.
There are two ways to get here: the normal way -- being called by
VG_(client_syscall), and the unusual way, from
VG_(fixup_guest_state_after_syscall_interrupted).
Darwin: there's a third way, ML_(wqthread_continue).
*/
void VG_(post_syscall) (ThreadId tid)
{
SyscallInfo* sci;
const SyscallTableEntry* ent;
SyscallStatus test_status;
ThreadState* tst;
Word sysno;
/* Preliminaries */
vg_assert(VG_(is_valid_tid)(tid));
vg_assert(tid >= 1 && tid < VG_N_THREADS);
vg_assert(VG_(is_running_thread)(tid));
tst = VG_(get_ThreadState)(tid);
sci = & syscallInfo[tid];
/* m_signals.sigvgkill_handler might call here even when not in
a syscall. */
if (sci->status.what == SsIdle || sci->status.what == SsHandToKernel) {
sci->status.what = SsIdle;
return;
}
/* Validate current syscallInfo entry. In particular we require
that the current .status matches what's actually in the guest
state. At least in the normal case where we have actually
previously written the result into the guest state. */
vg_assert(sci->status.what == SsComplete);
getSyscallStatusFromGuestState( &test_status, &tst->arch.vex );
if (!(sci->flags & SfNoWriteResult))
vg_assert(eq_SyscallStatus( &sci->status, &test_status ));
/* Failure of the above assertion on Darwin can indicate a problem
in the syscall wrappers that pre-fail or pre-succeed the
syscall, by calling SET_STATUS_Success or SET_STATUS_Failure,
when they really should call SET_STATUS_from_SysRes. The former
create a UNIX-class syscall result on Darwin, which may not be
correct for the syscall; if that's the case then this assertion
fires. See PRE(thread_fast_set_cthread_self) for an example. On
non-Darwin platforms this assertion is should never fail, and this
comment is completely irrelevant. */
/* Ok, looks sane */
/* Get the system call number. Because the pre-handler isn't
allowed to mess with it, it should be the same for both the
original and potentially-modified args. */
vg_assert(sci->args.sysno == sci->orig_args.sysno);
sysno = sci->args.sysno;
ent = get_syscall_entry(sysno);
/* pre: status == Complete (asserted above) */
/* Consider either success or failure. Now run the post handler if:
- it exists, and
- Success or (Failure and PostOnFail is set)
*/
if (ent->after
&& ((!sr_isError(sci->status.sres))
|| (sr_isError(sci->status.sres)
&& (sci->flags & SfPostOnFail) ))) {
(ent->after)( tid, &sci->args, &sci->status );
}
/* Because the post handler might have changed the status (eg, the
post-handler for sys_open can change the result from success to
failure if the kernel supplied a fd that it doesn't like), once
again dump the syscall result back in the guest state.*/
if (!(sci->flags & SfNoWriteResult))
putSyscallStatusIntoGuestState( tid, &sci->status, &tst->arch.vex );
/* Do any post-syscall actions required by the tool. */
if (VG_(needs).syscall_wrapper) {
UWord tmpv[8];
tmpv[0] = sci->orig_args.arg1;
tmpv[1] = sci->orig_args.arg2;
tmpv[2] = sci->orig_args.arg3;
tmpv[3] = sci->orig_args.arg4;
tmpv[4] = sci->orig_args.arg5;
tmpv[5] = sci->orig_args.arg6;
tmpv[6] = sci->orig_args.arg7;
tmpv[7] = sci->orig_args.arg8;
VG_TDICT_CALL(tool_post_syscall, tid,
sysno,
&tmpv[0], sizeof(tmpv)/sizeof(tmpv[0]),
sci->status.sres);
}
/* The syscall is done. */
vg_assert(sci->status.what == SsComplete);
sci->status.what = SsIdle;
/* The pre/post wrappers may have concluded that pending signals
might have been created, and will have set SfPollAfter to
request a poll for them once the syscall is done. */
if (sci->flags & SfPollAfter)
VG_(poll_signals)(tid);
/* Similarly, the wrappers might have asked for a yield
afterwards. */
if (sci->flags & SfYieldAfter)
VG_(vg_yield)();
}
/* ---------------------------------------------------------------------
Dealing with syscalls which get interrupted by a signal:
VG_(fixup_guest_state_after_syscall_interrupted)
------------------------------------------------------------------ */
/* Syscalls done on behalf of the client are finally handed off to the
kernel in VG_(client_syscall) above, either by calling
do_syscall_for_client (the async case), or by calling
VG_(do_syscall6) (the sync case).
If the syscall is not interrupted by a signal (it may block and
later unblock, but that's irrelevant here) then those functions
eventually return and so control is passed to VG_(post_syscall).
NB: not sure if the sync case can actually get interrupted, as it
operates with all signals masked.
However, the syscall may get interrupted by an async-signal. In
that case do_syscall_for_client/VG_(do_syscall6) do not
return. Instead we wind up in m_signals.async_sighandler. We need
to fix up the guest state to make it look like the syscall was
interrupted for guest. So async_sighandler calls here, and this
does the fixup. Note that from here we wind up calling
VG_(post_syscall) too.
*/
/* These are addresses within ML_(do_syscall_for_client_WRK). See
syscall-$PLAT.S for details.
*/
#if defined(VGO_linux)
extern const Addr ML_(blksys_setup);
extern const Addr ML_(blksys_restart);
extern const Addr ML_(blksys_complete);
extern const Addr ML_(blksys_committed);
extern const Addr ML_(blksys_finished);
#elif defined(VGO_darwin)
/* Darwin requires extra uglyness */
extern const Addr ML_(blksys_setup_MACH);
extern const Addr ML_(blksys_restart_MACH);
extern const Addr ML_(blksys_complete_MACH);
extern const Addr ML_(blksys_committed_MACH);
extern const Addr ML_(blksys_finished_MACH);
extern const Addr ML_(blksys_setup_MDEP);
extern const Addr ML_(blksys_restart_MDEP);
extern const Addr ML_(blksys_complete_MDEP);
extern const Addr ML_(blksys_committed_MDEP);
extern const Addr ML_(blksys_finished_MDEP);
extern const Addr ML_(blksys_setup_UNIX);
extern const Addr ML_(blksys_restart_UNIX);
extern const Addr ML_(blksys_complete_UNIX);
extern const Addr ML_(blksys_committed_UNIX);
extern const Addr ML_(blksys_finished_UNIX);
#else
# error "Unknown OS"
#endif
/* Back up guest state to restart a system call. */
void ML_(fixup_guest_state_to_restart_syscall) ( ThreadArchState* arch )
{
#if defined(VGP_x86_linux)
arch->vex.guest_EIP -= 2; // sizeof(int $0x80)
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
int $0x80 == CD 80
*/
{
UChar *p = (UChar *)arch->vex.guest_EIP;
if (p[0] != 0xcd || p[1] != 0x80)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#x %02x %02x\n",
arch->vex.guest_EIP, p[0], p[1]);
vg_assert(p[0] == 0xcd && p[1] == 0x80);
}
#elif defined(VGP_amd64_linux)
arch->vex.guest_RIP -= 2; // sizeof(syscall)
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
syscall == 0F 05
*/
{
UChar *p = (UChar *)arch->vex.guest_RIP;
if (p[0] != 0x0F || p[1] != 0x05)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#llx %02x %02x\n",
arch->vex.guest_RIP, p[0], p[1]);
vg_assert(p[0] == 0x0F && p[1] == 0x05);
}
#elif defined(VGP_ppc32_linux) || defined(VGP_ppc64_linux)
arch->vex.guest_CIA -= 4; // sizeof(ppc32 instr)
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
sc == 44 00 00 02
*/
{
UChar *p = (UChar *)arch->vex.guest_CIA;
if (p[0] != 0x44 || p[1] != 0x0 || p[2] != 0x0 || p[3] != 0x02)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#llx %02x %02x %02x %02x\n",
arch->vex.guest_CIA + 0ULL, p[0], p[1], p[2], p[3]);
vg_assert(p[0] == 0x44 && p[1] == 0x0 && p[2] == 0x0 && p[3] == 0x2);
}
#elif defined(VGP_arm_linux)
if (arch->vex.guest_R15T & 1) {
// Thumb mode. SVC is a encoded as
// 1101 1111 imm8
// where imm8 is the SVC number, and we only accept 0.
arch->vex.guest_R15T -= 2; // sizeof(thumb 16 bit insn)
UChar* p = (UChar*)(arch->vex.guest_R15T - 1);
Bool valid = p[0] == 0 && p[1] == 0xDF;
if (!valid) {
VG_(message)(Vg_DebugMsg,
"?! restarting over (Thumb) syscall that is not syscall "
"at %#llx %02x %02x\n",
arch->vex.guest_R15T - 1ULL, p[0], p[1]);
}
vg_assert(valid);
// FIXME: NOTE, this really isn't right. We need to back up
// ITSTATE to what it was before the SVC instruction, but we
// don't know what it was. At least assert that it is now
// zero, because if it is nonzero then it must also have
// been nonzero for the SVC itself, which means it was
// conditional. Urk.
vg_assert(arch->vex.guest_ITSTATE == 0);
} else {
// ARM mode. SVC is encoded as
// cond 1111 imm24
// where imm24 is the SVC number, and we only accept 0.
arch->vex.guest_R15T -= 4; // sizeof(arm instr)
UChar* p = (UChar*)arch->vex.guest_R15T;
Bool valid = p[0] == 0 && p[1] == 0 && p[2] == 0
&& (p[3] & 0xF) == 0xF;
if (!valid) {
VG_(message)(Vg_DebugMsg,
"?! restarting over (ARM) syscall that is not syscall "
"at %#llx %02x %02x %02x %02x\n",
arch->vex.guest_R15T + 0ULL, p[0], p[1], p[2], p[3]);
}
vg_assert(valid);
}
#elif defined(VGP_arm64_linux)
arch->vex.guest_PC -= 4; // sizeof(arm64 instr)
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
svc #0 == d4 00 00 01
*/
{
UChar *p = (UChar *)arch->vex.guest_PC;
if (p[0] != 0x01 || p[1] != 0x00 || p[2] != 0x00 || p[3] != 0xD4)
VG_(message)(
Vg_DebugMsg,
"?! restarting over syscall at %#llx %02x %02x %02x %02x\n",
arch->vex.guest_PC + 0ULL, p[0], p[1], p[2], p[3]
);
vg_assert(p[0] == 0x01 && p[1] == 0x00 && p[2] == 0x00 && p[3] == 0xD4);
}
#elif defined(VGP_x86_darwin)
arch->vex.guest_EIP = arch->vex.guest_IP_AT_SYSCALL;
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
int $0x80 == CD 80
int $0x81 == CD 81
int $0x82 == CD 82
sysenter == 0F 34
*/
{
UChar *p = (UChar *)arch->vex.guest_EIP;
Bool ok = (p[0] == 0xCD && p[1] == 0x80)
|| (p[0] == 0xCD && p[1] == 0x81)
|| (p[0] == 0xCD && p[1] == 0x82)
|| (p[0] == 0x0F && p[1] == 0x34);
if (!ok)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#x %02x %02x\n",
arch->vex.guest_EIP, p[0], p[1]);
vg_assert(ok);
}
#elif defined(VGP_amd64_darwin)
// DDD: #warning GrP fixme amd64 restart unimplemented
vg_assert(0);
#elif defined(VGP_s390x_linux)
arch->vex.guest_IA -= 2; // sizeof(syscall)
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
syscall == 0A <num>
*/
{
UChar *p = (UChar *)arch->vex.guest_IA;
if (p[0] != 0x0A)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#llx %02x %02x\n",
arch->vex.guest_IA, p[0], p[1]);
vg_assert(p[0] == 0x0A);
}
#elif defined(VGP_mips32_linux) || defined(VGP_mips64_linux)
arch->vex.guest_PC -= 4; // sizeof(mips instr)
/* Make sure our caller is actually sane, and we're really backing
back over a syscall.
syscall == 00 00 00 0C
big endian
syscall == 0C 00 00 00
*/
{
UChar *p = (UChar *)(arch->vex.guest_PC);
# if defined (VG_LITTLEENDIAN)
if (p[0] != 0x0c || p[1] != 0x00 || p[2] != 0x00 || p[3] != 0x00)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#llx %02x %02x %02x %02x\n",
(ULong)arch->vex.guest_PC, p[0], p[1], p[2], p[3]);
vg_assert(p[0] == 0x0c && p[1] == 0x00 && p[2] == 0x00 && p[3] == 0x00);
# elif defined (VG_BIGENDIAN)
if (p[0] != 0x00 || p[1] != 0x00 || p[2] != 0x00 || p[3] != 0x0c)
VG_(message)(Vg_DebugMsg,
"?! restarting over syscall at %#llx %02x %02x %02x %02x\n",
(ULong)arch->vex.guest_PC, p[0], p[1], p[2], p[3]);
vg_assert(p[0] == 0x00 && p[1] == 0x00 && p[2] == 0x00 && p[3] == 0x0c);
# else
# error "Unknown endianness"
# endif
}
#else
# error "ML_(fixup_guest_state_to_restart_syscall): unknown plat"
#endif
}
/*
Fix up the guest state when a syscall is interrupted by a signal
and so has been forced to return 'sysret'.
To do this, we determine the precise state of the syscall by
looking at the (real) IP at the time the signal happened. The
syscall sequence looks like:
1. unblock signals
2. perform syscall
3. save result to guest state (EAX, RAX, R3+CR0.SO, R0, V0)
4. re-block signals
If a signal
happens at Then Why?
[1-2) restart nothing has happened (restart syscall)
[2] restart syscall hasn't started, or kernel wants to restart
[2-3) save syscall complete, but results not saved
[3-4) syscall complete, results saved
Sometimes we never want to restart an interrupted syscall (because
sigaction says not to), so we only restart if "restart" is True.
This will also call VG_(post_syscall) if the syscall has actually
completed (either because it was interrupted, or because it
actually finished). It will not call VG_(post_syscall) if the
syscall is set up for restart, which means that the pre-wrapper may
get called multiple times.
*/
void
VG_(fixup_guest_state_after_syscall_interrupted)( ThreadId tid,
Addr ip,
SysRes sres,
Bool restart)
{
/* Note that we don't know the syscall number here, since (1) in
general there's no reliable way to get hold of it short of
stashing it in the guest state before the syscall, and (2) in
any case we don't need to know it for the actions done by this
routine.
Furthermore, 'sres' is only used in the case where the syscall
is complete, but the result has not been committed to the guest
state yet. In any other situation it will be meaningless and
therefore ignored. */
ThreadState* tst;
SyscallStatus canonical;
ThreadArchState* th_regs;
SyscallInfo* sci;
/* Compute some Booleans indicating which range we're in. */
Bool outside_range,
in_setup_to_restart, // [1,2) in the .S files
at_restart, // [2] in the .S files
in_complete_to_committed, // [3,4) in the .S files
in_committed_to_finished; // [4,5) in the .S files
# if defined(VGO_linux)
outside_range
= ip < ML_(blksys_setup) || ip >= ML_(blksys_finished);
in_setup_to_restart
= ip >= ML_(blksys_setup) && ip < ML_(blksys_restart);
at_restart
= ip == ML_(blksys_restart);
in_complete_to_committed
= ip >= ML_(blksys_complete) && ip < ML_(blksys_committed);
in_committed_to_finished
= ip >= ML_(blksys_committed) && ip < ML_(blksys_finished);
# elif defined(VGO_darwin)
outside_range
= (ip < ML_(blksys_setup_MACH) || ip >= ML_(blksys_finished_MACH))
&& (ip < ML_(blksys_setup_MDEP) || ip >= ML_(blksys_finished_MDEP))
&& (ip < ML_(blksys_setup_UNIX) || ip >= ML_(blksys_finished_UNIX));
in_setup_to_restart
= (ip >= ML_(blksys_setup_MACH) && ip < ML_(blksys_restart_MACH))
|| (ip >= ML_(blksys_setup_MDEP) && ip < ML_(blksys_restart_MDEP))
|| (ip >= ML_(blksys_setup_UNIX) && ip < ML_(blksys_restart_UNIX));
at_restart
= (ip == ML_(blksys_restart_MACH))
|| (ip == ML_(blksys_restart_MDEP))
|| (ip == ML_(blksys_restart_UNIX));
in_complete_to_committed
= (ip >= ML_(blksys_complete_MACH) && ip < ML_(blksys_committed_MACH))
|| (ip >= ML_(blksys_complete_MDEP) && ip < ML_(blksys_committed_MDEP))
|| (ip >= ML_(blksys_complete_UNIX) && ip < ML_(blksys_committed_UNIX));
in_committed_to_finished
= (ip >= ML_(blksys_committed_MACH) && ip < ML_(blksys_finished_MACH))
|| (ip >= ML_(blksys_committed_MDEP) && ip < ML_(blksys_finished_MDEP))
|| (ip >= ML_(blksys_committed_UNIX) && ip < ML_(blksys_finished_UNIX));
/* Wasn't that just So Much Fun? Does your head hurt yet? Mine does. */
# else
# error "Unknown OS"
# endif
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg,
"interrupted_syscall: tid=%d, ip=0x%llx, "
"restart=%s, sres.isErr=%s, sres.val=%lld\n",
(Int)tid,
(ULong)ip,
restart ? "True" : "False",
sr_isError(sres) ? "True" : "False",
(Long)(sr_isError(sres) ? sr_Err(sres) : sr_Res(sres)) );
vg_assert(VG_(is_valid_tid)(tid));
vg_assert(tid >= 1 && tid < VG_N_THREADS);
vg_assert(VG_(is_running_thread)(tid));
tst = VG_(get_ThreadState)(tid);
th_regs = &tst->arch;
sci = & syscallInfo[tid];
/* Figure out what the state of the syscall was by examining the
(real) IP at the time of the signal, and act accordingly. */
if (outside_range) {
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg,
" not in syscall at all: hmm, very suspicious\n" );
/* Looks like we weren't in a syscall at all. Hmm. */
vg_assert(sci->status.what != SsIdle);
return;
}
/* We should not be here unless this thread had first started up
the machinery for a syscall by calling VG_(client_syscall).
Hence: */
vg_assert(sci->status.what != SsIdle);
/* now, do one of four fixup actions, depending on where the IP has
got to. */
if (in_setup_to_restart) {
/* syscall hasn't even started; go around again */
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg, " not started: restarting\n");
vg_assert(sci->status.what == SsHandToKernel);
ML_(fixup_guest_state_to_restart_syscall)(th_regs);
}
else
if (at_restart) {
/* We're either about to run the syscall, or it was interrupted
and the kernel restarted it. Restart if asked, otherwise
EINTR it. */
if (restart) {
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg, " at syscall instr: restarting\n");
ML_(fixup_guest_state_to_restart_syscall)(th_regs);
} else {
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg, " at syscall instr: returning EINTR\n");
canonical = convert_SysRes_to_SyscallStatus(
VG_(mk_SysRes_Error)( VKI_EINTR )
);
if (!(sci->flags & SfNoWriteResult))
putSyscallStatusIntoGuestState( tid, &canonical, &th_regs->vex );
sci->status = canonical;
VG_(post_syscall)(tid);
}
}
else
if (in_complete_to_committed) {
/* Syscall complete, but result hasn't been written back yet.
Write the SysRes we were supplied with back to the guest
state. */
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg,
" completed, but uncommitted: committing\n");
canonical = convert_SysRes_to_SyscallStatus( sres );
if (!(sci->flags & SfNoWriteResult))
putSyscallStatusIntoGuestState( tid, &canonical, &th_regs->vex );
sci->status = canonical;
VG_(post_syscall)(tid);
}
else
if (in_committed_to_finished) {
/* Result committed, but the signal mask has not been restored;
we expect our caller (the signal handler) will have fixed
this up. */
if (VG_(clo_trace_signals))
VG_(message)( Vg_DebugMsg,
" completed and committed: nothing to do\n");
getSyscallStatusFromGuestState( &sci->status, &th_regs->vex );
vg_assert(sci->status.what == SsComplete);
VG_(post_syscall)(tid);
}
else
VG_(core_panic)("?? strange syscall interrupt state?");
/* In all cases, the syscall is now finished (even if we called
ML_(fixup_guest_state_to_restart_syscall), since that just
re-positions the guest's IP for another go at it). So we need
to record that fact. */
sci->status.what = SsIdle;
}
#if defined(VGO_darwin)
// Clean up after workq_ops(WQOPS_THREAD_RETURN) jumped to wqthread_hijack.
// This is similar to VG_(fixup_guest_state_after_syscall_interrupted).
// This longjmps back to the scheduler.
void ML_(wqthread_continue_NORETURN)(ThreadId tid)
{
ThreadState* tst;
SyscallInfo* sci;
VG_(acquire_BigLock)(tid, "wqthread_continue_NORETURN");
PRINT("SYSCALL[%d,%d](%s) workq_ops() starting new workqueue item\n",
VG_(getpid)(), tid, VG_SYSNUM_STRING(__NR_workq_ops));
vg_assert(VG_(is_valid_tid)(tid));
vg_assert(tid >= 1 && tid < VG_N_THREADS);
vg_assert(VG_(is_running_thread)(tid));
tst = VG_(get_ThreadState)(tid);
sci = & syscallInfo[tid];
vg_assert(sci->status.what != SsIdle);
vg_assert(tst->os_state.wq_jmpbuf_valid); // check this BEFORE post_syscall
// Pretend the syscall completed normally, but don't touch the thread state.
sci->status = convert_SysRes_to_SyscallStatus( VG_(mk_SysRes_Success)(0) );
sci->flags |= SfNoWriteResult;
VG_(post_syscall)(tid);
sci->status.what = SsIdle;
vg_assert(tst->sched_jmpbuf_valid);
VG_MINIMAL_LONGJMP(tst->sched_jmpbuf);
/* NOTREACHED */
vg_assert(0);
}
#endif
/* ---------------------------------------------------------------------
A place to store the where-to-call-when-really-done pointer
------------------------------------------------------------------ */
// When the final thread is done, where shall I call to shutdown the
// system cleanly? Is set once at startup (in m_main) and never
// changes after that. Is basically a pointer to the exit
// continuation. This is all just a nasty hack to avoid calling
// directly from m_syswrap to m_main at exit, since that would cause
// m_main to become part of a module cycle, which is silly.
void (* VG_(address_of_m_main_shutdown_actions_NORETURN) )
(ThreadId,VgSchedReturnCode)
= NULL;
/*--------------------------------------------------------------------*/
/*--- end ---*/
/*--------------------------------------------------------------------*/