platform_bionic/libc/bionic/poll.cpp
Josh Gao 6fcba93b17 Filter out reserved signals in functions that take sigset_t.
Prevent processes from blocking libc-reserved signals by filtering them
out.

Bug: http://b/73144101
Test: 32/64-bit bionic-unit-tests-glibc
Test: 32/64-bit bionic-unit-tests on taimen
Change-Id: Ibadcaa7f668ed8be885cc61b67fb4b611fce8b17
2018-02-27 14:12:30 -08:00

139 lines
4.6 KiB
C++

/*
* Copyright (C) 2013 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <errno.h>
#include <sys/poll.h>
#include <sys/select.h>
#include "private/bionic_time_conversions.h"
#include "private/sigrtmin.h"
#include "private/SigSetConverter.h"
extern "C" int __ppoll(pollfd*, unsigned int, timespec*, const sigset64_t*, size_t);
extern "C" int __pselect6(int, fd_set*, fd_set*, fd_set*, timespec*, void*);
int poll(pollfd* fds, nfds_t fd_count, int ms) {
timespec ts;
timespec* ts_ptr = nullptr;
if (ms >= 0) {
timespec_from_ms(ts, ms);
ts_ptr = &ts;
}
return __ppoll(fds, fd_count, ts_ptr, nullptr, 0);
}
int ppoll(pollfd* fds, nfds_t fd_count, const timespec* ts, const sigset_t* ss) {
// The underlying `__ppoll` system call only takes `sigset64_t`.
SigSetConverter set;
sigset64_t* ss_ptr = nullptr;
if (ss != nullptr) {
set = {};
set.sigset = *ss;
ss_ptr = &set.sigset64;
}
return ppoll64(fds, fd_count, ts, ss_ptr);
}
int ppoll64(pollfd* fds, nfds_t fd_count, const timespec* ts, const sigset64_t* ss) {
// The underlying __ppoll system call modifies its `struct timespec` argument.
timespec mutable_ts;
timespec* mutable_ts_ptr = nullptr;
if (ts != nullptr) {
mutable_ts = *ts;
mutable_ts_ptr = &mutable_ts;
}
sigset64_t mutable_ss;
sigset64_t* mutable_ss_ptr = nullptr;
if (ss != nullptr) {
mutable_ss = filter_reserved_signals(*ss);
mutable_ss_ptr = &mutable_ss;
}
return __ppoll(fds, fd_count, mutable_ts_ptr, mutable_ss_ptr, sizeof(*mutable_ss_ptr));
}
int select(int fd_count, fd_set* read_fds, fd_set* write_fds, fd_set* error_fds, timeval* tv) {
timespec ts;
timespec* ts_ptr = nullptr;
if (tv != nullptr) {
if (!timespec_from_timeval(ts, *tv)) {
errno = EINVAL;
return -1;
}
ts_ptr = &ts;
}
int result = __pselect6(fd_count, read_fds, write_fds, error_fds, ts_ptr, nullptr);
if (tv != nullptr) {
timeval_from_timespec(*tv, ts);
}
return result;
}
int pselect(int fd_count, fd_set* read_fds, fd_set* write_fds, fd_set* error_fds,
const timespec* ts, const sigset_t* ss) {
// The underlying `__pselect6` system call only takes `sigset64_t`.
SigSetConverter set;
sigset64_t* ss_ptr = nullptr;
if (ss != nullptr) {
set = {};
set.sigset = *ss;
ss_ptr = &set.sigset64;
}
return pselect64(fd_count, read_fds, write_fds, error_fds, ts, ss_ptr);
}
int pselect64(int fd_count, fd_set* read_fds, fd_set* write_fds, fd_set* error_fds,
const timespec* ts, const sigset64_t* ss) {
// The underlying __pselect6 system call modifies its `struct timespec` argument.
timespec mutable_ts;
timespec* mutable_ts_ptr = nullptr;
if (ts != nullptr) {
mutable_ts = *ts;
mutable_ts_ptr = &mutable_ts;
}
sigset64_t mutable_ss;
sigset64_t* mutable_ss_ptr = nullptr;
if (ss != nullptr) {
mutable_ss = filter_reserved_signals(*ss);
mutable_ss_ptr = &mutable_ss;
}
// The Linux kernel only handles 6 arguments and this system call really needs 7,
// so the last argument is a void* pointing to:
struct pselect6_extra_data_t {
uintptr_t ss_addr;
size_t ss_len;
};
pselect6_extra_data_t extra_data;
extra_data.ss_addr = reinterpret_cast<uintptr_t>(mutable_ss_ptr);
extra_data.ss_len = sizeof(*mutable_ss_ptr);
return __pselect6(fd_count, read_fds, write_fds, error_fds, mutable_ts_ptr, &extra_data);
}