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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "debug.h"
#include "sandbox_impl.h"
namespace playground {
// If the sandboxed process tries to mask SIGSEGV, there is a good chance
// the process will eventually get terminated. If this is really ever a
// problem, we can hide the fact that SIGSEGV is unmasked. But I don't think
// we really need this. Masking of synchronous signals is rarely necessary.
#if defined(__NR_sigprocmask)
long Sandbox::sandbox_sigprocmask(int how, const void* set, void* old_set) {
long long tm;
Debug::syscall(&tm, __NR_sigprocmask, "Executing handler");
// Access the signal mask by triggering a SEGV and modifying the signal state
// prior to calling rt_sigreturn().
long res = -ENOSYS;
#if defined(__x86_64__)
#error x86-64 does not support sigprocmask(); use rt_sigprocmask() instead
#elif defined(__i386__)
asm volatile(
"push %%ebx\n"
"movl %2, %%ebx\n"
"int $0\n"
"pop %%ebx\n"
: "=a"(res)
: "0"(__NR_sigprocmask), "ri"((long)how),
"c"((long)set), "d"((long)old_set)
: "esp", "memory");
#else
#error Unsupported target platform
#endif
// Update our shadow signal mask, so that we can copy it upon creation of
// new threads.
if (res == 0 && set != NULL) {
SecureMem::Args* args = getSecureMem();
switch (how) {
case SIG_BLOCK:
*(unsigned long long *)&args->signalMask |= *(unsigned long long *)set;
break;
case SIG_UNBLOCK:
*(unsigned long long *)&args->signalMask &= ~*(unsigned long long *)set;
break;
case SIG_SETMASK:
*(unsigned long long *)&args->signalMask = *(unsigned long long *)set;
break;
default:
break;
}
}
Debug::elapsed(tm, __NR_sigprocmask);
return res;
}
#endif
#if defined(__NR_rt_sigprocmask)
long Sandbox::sandbox_rt_sigprocmask(int how, const void* set, void* old_set,
size_t bytes) {
long long tm;
Debug::syscall(&tm, __NR_rt_sigprocmask, "Executing handler");
// Access the signal mask by triggering a SEGV and modifying the signal state
// prior to calling rt_sigreturn().
long res = -ENOSYS;
#if defined(__x86_64__)
asm volatile(
"movq %5, %%r10\n"
"int $0\n"
: "=a"(res)
: "0"(__NR_rt_sigprocmask), "D"((long)how),
"S"((long)set), "d"((long)old_set), "r"((long)bytes)
: "r10", "r11", "rcx", "memory");
#elif defined(__i386__)
asm volatile(
"push %%ebx\n"
"movl %2, %%ebx\n"
"int $0\n"
"pop %%ebx\n"
: "=a"(res)
: "0"(__NR_rt_sigprocmask), "ri"((long)how),
"c"((long)set), "d"((long)old_set), "S"((long)bytes)
: "esp", "memory");
#else
#error Unsupported target platform
#endif
// Update our shadow signal mask, so that we can copy it upon creation of
// new threads.
if (res == 0 && set != NULL && bytes >= 8) {
SecureMem::Args* args = getSecureMem();
switch (how) {
case SIG_BLOCK:
*(unsigned long long *)&args->signalMask |= *(unsigned long long *)set;
break;
case SIG_UNBLOCK:
*(unsigned long long *)&args->signalMask &= ~*(unsigned long long *)set;
break;
case SIG_SETMASK:
*(unsigned long long *)&args->signalMask = *(unsigned long long *)set;
break;
default:
break;
}
}
Debug::elapsed(tm, __NR_rt_sigprocmask);
return res;
}
#endif
} // namespace
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