tor-android/external/badvpn_dns/system/BUnixSignal.c

407 lines
11 KiB
C

/**
* @file BUnixSignal.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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 AUTHOR 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 <inttypes.h>
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#ifdef BADVPN_USE_SIGNALFD
#include <sys/signalfd.h>
#endif
#include <misc/balloc.h>
#include <misc/nonblocking.h>
#include <base/BLog.h>
#include <system/BUnixSignal.h>
#include <generated/blog_channel_BUnixSignal.h>
#define BUNIXSIGNAL_MAX_SIGNALS 64
#ifdef BADVPN_USE_SIGNALFD
static void signalfd_handler (BUnixSignal *o, int events)
{
DebugObject_Access(&o->d_obj);
// read a signal
struct signalfd_siginfo siginfo;
int bytes = read(o->signalfd_fd, &siginfo, sizeof(siginfo));
if (bytes < 0) {
int error = errno;
if (error == EAGAIN || error == EWOULDBLOCK) {
return;
}
BLog(BLOG_ERROR, "read failed (%d)", error);
return;
}
ASSERT_FORCE(bytes == sizeof(siginfo))
// check signal
if (siginfo.ssi_signo > INT_MAX) {
BLog(BLOG_ERROR, "read returned out of int range signo (%"PRIu32")", siginfo.ssi_signo);
return;
}
int signo = siginfo.ssi_signo;
if (sigismember(&o->signals, signo) <= 0) {
BLog(BLOG_ERROR, "read returned wrong signo (%d)", signo);
return;
}
BLog(BLOG_DEBUG, "dispatching signal %d", signo);
// call handler
o->handler(o->user, signo);
return;
}
#endif
#ifdef BADVPN_USE_KEVENT
static void kevent_handler (struct BUnixSignal_kevent_entry *entry, u_int fflags, intptr_t data)
{
BUnixSignal *o = entry->parent;
DebugObject_Access(&o->d_obj);
// call signal
o->handler(o->user, entry->signo);
return;
}
#endif
#ifdef BADVPN_USE_SELFPIPE
struct BUnixSignal_selfpipe_entry *bunixsignal_selfpipe_entries[BUNIXSIGNAL_MAX_SIGNALS];
static void free_selfpipe_entry (struct BUnixSignal_selfpipe_entry *entry)
{
BUnixSignal *o = entry->parent;
// uninstall signal handler
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = SIG_DFL;
sigemptyset(&act.sa_mask);
ASSERT_FORCE(sigaction(entry->signo, &act, NULL) == 0)
// free BFileDescriptor
BReactor_RemoveFileDescriptor(o->reactor, &entry->pipe_read_bfd);
// close pipe
ASSERT_FORCE(close(entry->pipefds[0]) == 0)
ASSERT_FORCE(close(entry->pipefds[1]) == 0)
}
static void pipe_read_fd_handler (struct BUnixSignal_selfpipe_entry *entry, int events)
{
BUnixSignal *o = entry->parent;
DebugObject_Access(&o->d_obj);
// read a byte
uint8_t b;
if (read(entry->pipefds[0], &b, sizeof(b)) < 0) {
int error = errno;
if (error == EAGAIN || error == EWOULDBLOCK) {
return;
}
BLog(BLOG_ERROR, "read failed (%d)", error);
return;
}
// call handler
o->handler(o->user, entry->signo);
return;
}
static void signal_handler (int signo)
{
ASSERT(signo >= 0)
ASSERT(signo < BUNIXSIGNAL_MAX_SIGNALS)
struct BUnixSignal_selfpipe_entry *entry = bunixsignal_selfpipe_entries[signo];
uint8_t b = 0;
write(entry->pipefds[1], &b, sizeof(b));
}
#endif
int BUnixSignal_Init (BUnixSignal *o, BReactor *reactor, sigset_t signals, BUnixSignal_handler handler, void *user)
{
// init arguments
o->reactor = reactor;
o->signals = signals;
o->handler = handler;
o->user = user;
#ifdef BADVPN_USE_SIGNALFD
// init signalfd fd
if ((o->signalfd_fd = signalfd(-1, &o->signals, 0)) < 0) {
BLog(BLOG_ERROR, "signalfd failed");
goto fail0;
}
// set non-blocking
if (fcntl(o->signalfd_fd, F_SETFL, O_NONBLOCK) < 0) {
BLog(BLOG_ERROR, "cannot set non-blocking");
goto fail1;
}
// init signalfd BFileDescriptor
BFileDescriptor_Init(&o->signalfd_bfd, o->signalfd_fd, (BFileDescriptor_handler)signalfd_handler, o);
if (!BReactor_AddFileDescriptor(o->reactor, &o->signalfd_bfd)) {
BLog(BLOG_ERROR, "BReactor_AddFileDescriptor failed");
goto fail1;
}
BReactor_SetFileDescriptorEvents(o->reactor, &o->signalfd_bfd, BREACTOR_READ);
// block signals
if (sigprocmask(SIG_BLOCK, &o->signals, 0) < 0) {
BLog(BLOG_ERROR, "sigprocmask block failed");
goto fail2;
}
#endif
#ifdef BADVPN_USE_KEVENT
// count signals
int num_signals = 0;
for (int i = 0; i < BUNIXSIGNAL_MAX_SIGNALS; i++) {
if (!sigismember(&o->signals, i)) {
continue;
}
num_signals++;
}
// allocate array
if (!(o->entries = BAllocArray(num_signals, sizeof(o->entries[0])))) {
BLog(BLOG_ERROR, "BAllocArray failed");
goto fail0;
}
// init kevents
o->num_entries = 0;
for (int i = 0; i < BUNIXSIGNAL_MAX_SIGNALS; i++) {
if (!sigismember(&o->signals, i)) {
continue;
}
struct BUnixSignal_kevent_entry *entry = &o->entries[o->num_entries];
entry->parent = o;
entry->signo = i;
if (!BReactorKEvent_Init(&entry->kevent, o->reactor, (BReactorKEvent_handler)kevent_handler, entry, entry->signo, EVFILT_SIGNAL, 0, 0)) {
BLog(BLOG_ERROR, "BReactorKEvent_Init failed");
goto fail2;
}
o->num_entries++;
}
// block signals
if (sigprocmask(SIG_BLOCK, &o->signals, 0) < 0) {
BLog(BLOG_ERROR, "sigprocmask block failed");
goto fail2;
}
#endif
#ifdef BADVPN_USE_SELFPIPE
// count signals
int num_signals = 0;
for (int i = 1; i < BUNIXSIGNAL_MAX_SIGNALS; i++) {
if (!sigismember(&o->signals, i)) {
continue;
}
num_signals++;
}
// allocate array
if (!(o->entries = BAllocArray(num_signals, sizeof(o->entries[0])))) {
BLog(BLOG_ERROR, "BAllocArray failed");
goto fail0;
}
// init entries
o->num_entries = 0;
for (int i = 1; i < BUNIXSIGNAL_MAX_SIGNALS; i++) {
if (!sigismember(&o->signals, i)) {
continue;
}
struct BUnixSignal_selfpipe_entry *entry = &o->entries[o->num_entries];
entry->parent = o;
entry->signo = i;
// init pipe
if (pipe(entry->pipefds) < 0) {
BLog(BLOG_ERROR, "pipe failed");
goto loop_fail0;
}
// set pipe ends non-blocking
if (!badvpn_set_nonblocking(entry->pipefds[0]) || !badvpn_set_nonblocking(entry->pipefds[1])) {
BLog(BLOG_ERROR, "set nonblocking failed");
goto loop_fail1;
}
// init read end BFileDescriptor
BFileDescriptor_Init(&entry->pipe_read_bfd, entry->pipefds[0], (BFileDescriptor_handler)pipe_read_fd_handler, entry);
if (!BReactor_AddFileDescriptor(o->reactor, &entry->pipe_read_bfd)) {
BLog(BLOG_ERROR, "BReactor_AddFileDescriptor failed");
goto loop_fail1;
}
BReactor_SetFileDescriptorEvents(o->reactor, &entry->pipe_read_bfd, BREACTOR_READ);
// set global entry pointer
bunixsignal_selfpipe_entries[entry->signo] = entry;
// install signal handler
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = signal_handler;
sigemptyset(&act.sa_mask);
if (sigaction(entry->signo, &act, NULL) < 0) {
BLog(BLOG_ERROR, "sigaction failed");
goto loop_fail2;
}
o->num_entries++;
continue;
loop_fail2:
BReactor_RemoveFileDescriptor(o->reactor, &entry->pipe_read_bfd);
loop_fail1:
ASSERT_FORCE(close(entry->pipefds[0]) == 0)
ASSERT_FORCE(close(entry->pipefds[1]) == 0)
loop_fail0:
goto fail2;
}
#endif
DebugObject_Init(&o->d_obj);
return 1;
#ifdef BADVPN_USE_SIGNALFD
fail2:
BReactor_RemoveFileDescriptor(o->reactor, &o->signalfd_bfd);
fail1:
ASSERT_FORCE(close(o->signalfd_fd) == 0)
#endif
#ifdef BADVPN_USE_KEVENT
fail2:
while (o->num_entries > 0) {
BReactorKEvent_Free(&o->entries[o->num_entries - 1].kevent);
o->num_entries--;
}
BFree(o->entries);
#endif
#ifdef BADVPN_USE_SELFPIPE
fail2:
while (o->num_entries > 0) {
free_selfpipe_entry(&o->entries[o->num_entries - 1]);
o->num_entries--;
}
BFree(o->entries);
#endif
fail0:
return 0;
}
void BUnixSignal_Free (BUnixSignal *o, int unblock)
{
ASSERT(unblock == 0 || unblock == 1)
DebugObject_Free(&o->d_obj);
#ifdef BADVPN_USE_SIGNALFD
if (unblock) {
// unblock signals
ASSERT_FORCE(sigprocmask(SIG_UNBLOCK, &o->signals, 0) == 0)
}
// free signalfd BFileDescriptor
BReactor_RemoveFileDescriptor(o->reactor, &o->signalfd_bfd);
// free signalfd fd
ASSERT_FORCE(close(o->signalfd_fd) == 0)
#endif
#ifdef BADVPN_USE_KEVENT
if (unblock) {
// unblock signals
ASSERT_FORCE(sigprocmask(SIG_UNBLOCK, &o->signals, 0) == 0)
}
// free kevents
while (o->num_entries > 0) {
BReactorKEvent_Free(&o->entries[o->num_entries - 1].kevent);
o->num_entries--;
}
// free array
BFree(o->entries);
#endif
#ifdef BADVPN_USE_SELFPIPE
if (!unblock) {
// block signals
if (sigprocmask(SIG_BLOCK, &o->signals, 0) < 0) {
BLog(BLOG_ERROR, "sigprocmask block failed");
}
}
// free entries
while (o->num_entries > 0) {
free_selfpipe_entry(&o->entries[o->num_entries - 1]);
o->num_entries--;
}
// free array
BFree(o->entries);
#endif
}