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libsysutils: Fix race condition in SocketListener thread.

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+ Handle EINTR in accept(), write() and select()
+ Fix a memory leak when deleting the mClients list
+ Fix typo in SocketListener.h

Change-Id: Ie68bb3e2dbefe0dfdaa22a5cd06a42dbc4c0f8aa
This commit is contained in:
David 'Digit' Turner 2011-01-17 03:10:31 +01:00
parent af61509b50
commit cf9e1003ce
2 changed files with 54 additions and 29 deletions
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2
include/sysutils/SocketListener.h
View file

@ -30,7 +30,7 @@ class SocketListener {
pthread_t mThread;
public:
SocketListener(const char *socketNames, bool listen);
SocketListener(const char *socketName, bool listen);
SocketListener(int socketFd, bool listen);
virtual ~SocketListener();

81
libsysutils/src/SocketListener.cpp
View file

@ -54,7 +54,7 @@ SocketListener::~SocketListener() {
close(mCtrlPipe[1]);
}
SocketClientCollection::iterator it;
for (it = mClients->begin(); it != mClients->end(); ++it) {
for (it = mClients->begin(); it != mClients->end();) {
delete (*it);
it = mClients->erase(it);
}
@ -96,8 +96,10 @@ int SocketListener::startListener() {
int SocketListener::stopListener() {
char c = 0;
int rc;
if (write(mCtrlPipe[1], &c, 1) != 1) {
rc = TEMP_FAILURE_RETRY(write(mCtrlPipe[1], &c, 1));
if (rc != 1) {
SLOGE("Error writing to control pipe (%s)", strerror(errno));
return -1;
}
@ -118,7 +120,7 @@ int SocketListener::stopListener() {
}
SocketClientCollection::iterator it;
for (it = mClients->begin(); it != mClients->end(); ++it) {
for (it = mClients->begin(); it != mClients->end();) {
delete (*it);
it = mClients->erase(it);
}
@ -135,11 +137,13 @@ void *SocketListener::threadStart(void *obj) {
void SocketListener::runListener() {
SocketClientCollection *pendingList = new SocketClientCollection();
while(1) {
SocketClientCollection::iterator it;
fd_set read_fds;
int rc = 0;
int max = 0;
int max = -1;
FD_ZERO(&read_fds);
@ -154,13 +158,16 @@ void SocketListener::runListener() {
pthread_mutex_lock(&mClientsLock);
for (it = mClients->begin(); it != mClients->end(); ++it) {
FD_SET((*it)->getSocket(), &read_fds);
if ((*it)->getSocket() > max)
max = (*it)->getSocket();
int fd = (*it)->getSocket();
FD_SET(fd, &read_fds);
if (fd > max)
max = fd;
}
pthread_mutex_unlock(&mClientsLock);
if ((rc = select(max + 1, &read_fds, NULL, NULL, NULL)) < 0) {
if (errno == EINTR)
continue;
SLOGE("select failed (%s)", strerror(errno));
sleep(1);
continue;
@ -171,10 +178,14 @@ void SocketListener::runListener() {
break;
if (mListen && FD_ISSET(mSock, &read_fds)) {
struct sockaddr addr;
socklen_t alen = sizeof(addr);
socklen_t alen;
int c;
if ((c = accept(mSock, &addr, &alen)) < 0) {
do {
alen = sizeof(addr);
c = accept(mSock, &addr, &alen);
} while (c < 0 && errno == EINTR);
if (c < 0) {
SLOGE("accept failed (%s)", strerror(errno));
sleep(1);
continue;
@ -184,27 +195,41 @@ void SocketListener::runListener() {
pthread_mutex_unlock(&mClientsLock);
}
do {
pthread_mutex_lock(&mClientsLock);
for (it = mClients->begin(); it != mClients->end(); ++it) {
int fd = (*it)->getSocket();
if (FD_ISSET(fd, &read_fds)) {
pthread_mutex_unlock(&mClientsLock);
if (!onDataAvailable(*it)) {
close(fd);
pthread_mutex_lock(&mClientsLock);
delete *it;
it = mClients->erase(it);
pthread_mutex_unlock(&mClientsLock);
}
FD_CLR(fd, &read_fds);
pthread_mutex_lock(&mClientsLock);
continue;
}
/* Add all active clients to the pending list first */
pendingList->clear();
pthread_mutex_lock(&mClientsLock);
for (it = mClients->begin(); it != mClients->end(); ++it) {
int fd = (*it)->getSocket();
if (FD_ISSET(fd, &read_fds)) {
pendingList->push_back(*it);
}
pthread_mutex_unlock(&mClientsLock);
} while (0);
}
pthread_mutex_unlock(&mClientsLock);
/* Process the pending list, since it is owned by the thread,
* there is no need to lock it */
while (!pendingList->empty()) {
/* Pop the first item from the list */
it = pendingList->begin();
SocketClient* c = *it;
pendingList->erase(it);
/* Process it, if false is returned, remove and destroy it */
if (!onDataAvailable(c)) {
/* Remove the client from our array */
pthread_mutex_lock(&mClientsLock);
for (it = mClients->begin(); it != mClients->end(); ++it) {
if (*it == c) {
mClients->erase(it);
break;
}
}
pthread_mutex_unlock(&mClientsLock);
/* Destroy the client */
delete c;
}
}
}
delete pendingList;
}
void SocketListener::sendBroadcast(int code, const char *msg, bool addErrno) {