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authorMarc Hoersken <info@marc-hoersken.de>2020-04-02 18:41:11 +0200
committerMarc Hoersken <info@marc-hoersken.de>2020-04-03 12:37:39 +0200
commit9657ecb15b387ce86421af738045ede8a72aab13 (patch)
tree954f5426b86c3f45d15b7a70f0f410c0b9139424 /tests
parent4506607b44ca15e6de0ad87cf205b0dd3c0a784c (diff)
sockfilt: fix race-condition of waiting threads and event handling
Fix race-condition of waiting threads finishing while events are already being processed which lead to invalid or skipped events. Use mutex to check for one event at a time or do post-processing. In addition to mutex-based locking use specific event as signal. Closes #5156
Diffstat (limited to 'tests')
-rw-r--r--tests/server/sockfilt.c246
1 files changed, 163 insertions, 83 deletions
diff --git a/tests/server/sockfilt.c b/tests/server/sockfilt.c
index 5403d7c42..9c43f90e4 100644
--- a/tests/server/sockfilt.c
+++ b/tests/server/sockfilt.c
@@ -532,12 +532,14 @@ static void lograw(unsigned char *buffer, ssize_t len)
*/
struct select_ws_wait_data {
HANDLE handle; /* actual handle to wait for during select */
- HANDLE event; /* internal event to abort waiting thread */
+ HANDLE signal; /* internal event to signal handle trigger */
+ HANDLE abort; /* internal event to abort waiting thread */
+ HANDLE mutex; /* mutex to prevent event race-condition */
};
static DWORD WINAPI select_ws_wait_thread(LPVOID lpParameter)
{
struct select_ws_wait_data *data;
- HANDLE handle, handles[2];
+ HANDLE mutex, signal, handle, handles[2];
INPUT_RECORD inputrecord;
LARGE_INTEGER size, pos;
DWORD type, length;
@@ -546,8 +548,10 @@ static DWORD WINAPI select_ws_wait_thread(LPVOID lpParameter)
data = (struct select_ws_wait_data *) lpParameter;
if(data) {
handle = data->handle;
- handles[0] = data->event;
+ handles[0] = data->abort;
handles[1] = handle;
+ signal = data->signal;
+ mutex = data->mutex;
free(data);
}
else
@@ -567,30 +571,41 @@ static DWORD WINAPI select_ws_wait_thread(LPVOID lpParameter)
*/
while(WaitForMultipleObjectsEx(1, handles, FALSE, 0, FALSE)
== WAIT_TIMEOUT) {
- /* get total size of file */
- length = 0;
- size.QuadPart = 0;
- size.LowPart = GetFileSize(handle, &length);
- if((size.LowPart != INVALID_FILE_SIZE) ||
- (GetLastError() == NO_ERROR)) {
- size.HighPart = length;
- /* get the current position within the file */
- pos.QuadPart = 0;
- pos.LowPart = SetFilePointer(handle, 0, &pos.HighPart,
- FILE_CURRENT);
- if((pos.LowPart != INVALID_SET_FILE_POINTER) ||
- (GetLastError() == NO_ERROR)) {
- /* compare position with size, abort if not equal */
- if(size.QuadPart == pos.QuadPart) {
- /* sleep and continue waiting */
- SleepEx(0, FALSE);
- continue;
+ length = WaitForSingleObjectEx(mutex, 0, FALSE);
+ if(length == WAIT_OBJECT_0) {
+ /* get total size of file */
+ length = 0;
+ size.QuadPart = 0;
+ size.LowPart = GetFileSize(handle, &length);
+ if((size.LowPart != INVALID_FILE_SIZE) ||
+ (GetLastError() == NO_ERROR)) {
+ size.HighPart = length;
+ /* get the current position within the file */
+ pos.QuadPart = 0;
+ pos.LowPart = SetFilePointer(handle, 0, &pos.HighPart,
+ FILE_CURRENT);
+ if((pos.LowPart != INVALID_SET_FILE_POINTER) ||
+ (GetLastError() == NO_ERROR)) {
+ /* compare position with size, abort if not equal */
+ if(size.QuadPart == pos.QuadPart) {
+ /* sleep and continue waiting */
+ SleepEx(0, FALSE);
+ ReleaseMutex(mutex);
+ continue;
+ }
}
}
+ /* there is some data available, stop waiting */
+ logmsg("[select_ws_wait_thread] data available, DISK: %p", handle);
+ SetEvent(signal);
+ ReleaseMutex(mutex);
+ break;
+ }
+ else if(length == WAIT_ABANDONED) {
+ /* we are not allowed to process this event, because select_ws
+ is post-processing the signalled events and we must exit. */
+ break;
}
- /* there is some data available, stop waiting */
- logmsg("[select_ws_wait_thread] data available on DISK: %p", handle);
- break;
}
break;
@@ -604,23 +619,34 @@ static DWORD WINAPI select_ws_wait_thread(LPVOID lpParameter)
*/
while(WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE)
== WAIT_OBJECT_0 + 1) {
- /* check if this is an actual console handle */
- length = 0;
- if(GetConsoleMode(handle, &length)) {
- /* retrieve an event from the console buffer */
+ length = WaitForSingleObjectEx(mutex, 0, FALSE);
+ if(length == WAIT_OBJECT_0) {
+ /* check if this is an actual console handle */
length = 0;
- if(PeekConsoleInput(handle, &inputrecord, 1, &length)) {
- /* check if the event is not an actual key-event */
- if(length == 1 && inputrecord.EventType != KEY_EVENT) {
- /* purge the non-key-event and continue waiting */
- ReadConsoleInput(handle, &inputrecord, 1, &length);
- continue;
+ if(GetConsoleMode(handle, &length)) {
+ /* retrieve an event from the console buffer */
+ length = 0;
+ if(PeekConsoleInput(handle, &inputrecord, 1, &length)) {
+ /* check if the event is not an actual key-event */
+ if(length == 1 && inputrecord.EventType != KEY_EVENT) {
+ /* purge the non-key-event and continue waiting */
+ ReadConsoleInput(handle, &inputrecord, 1, &length);
+ ReleaseMutex(mutex);
+ continue;
+ }
}
}
+ /* there is some data available, stop waiting */
+ logmsg("[select_ws_wait_thread] data available, CHAR: %p", handle);
+ SetEvent(signal);
+ ReleaseMutex(mutex);
+ break;
+ }
+ else if(length == WAIT_ABANDONED) {
+ /* we are not allowed to process this event, because select_ws
+ is post-processing the signalled events and we must exit. */
+ break;
}
- /* there is some data available, stop waiting */
- logmsg("[select_ws_wait_thread] data available on CHAR: %p", handle);
- break;
}
break;
@@ -634,43 +660,62 @@ static DWORD WINAPI select_ws_wait_thread(LPVOID lpParameter)
*/
while(WaitForMultipleObjectsEx(1, handles, FALSE, 0, FALSE)
== WAIT_TIMEOUT) {
- /* peek into the pipe and retrieve the amount of data available */
- length = 0;
- if(PeekNamedPipe(handle, NULL, 0, NULL, &length, NULL)) {
- /* if there is no data available, sleep and continue waiting */
- if(length == 0) {
- SleepEx(0, FALSE);
- continue;
+ length = WaitForSingleObjectEx(mutex, 0, FALSE);
+ if(length == WAIT_OBJECT_0) {
+ /* peek into the pipe and retrieve the amount of data available */
+ length = 0;
+ if(PeekNamedPipe(handle, NULL, 0, NULL, &length, NULL)) {
+ /* if there is no data available, sleep and continue waiting */
+ if(length == 0) {
+ SleepEx(0, FALSE);
+ ReleaseMutex(mutex);
+ continue;
+ }
+ else {
+ logmsg("[select_ws_wait_thread] PeekNamedPipe len: %d", length);
+ }
}
else {
- logmsg("[select_ws_wait_thread] PeekNamedPipe len: %d", length);
+ /* if the pipe has been closed, sleep and continue waiting */
+ length = GetLastError();
+ logmsg("[select_ws_wait_thread] PeekNamedPipe error: %d", length);
+ if(length == ERROR_BROKEN_PIPE) {
+ SleepEx(0, FALSE);
+ ReleaseMutex(mutex);
+ continue;
+ }
}
+ /* there is some data available, stop waiting */
+ logmsg("[select_ws_wait_thread] data available, PIPE: %p", handle);
+ SetEvent(signal);
+ ReleaseMutex(mutex);
+ break;
}
- else {
- /* if the pipe has been closed, sleep and continue waiting */
- length = GetLastError();
- logmsg("[select_ws_wait_thread] PeekNamedPipe error: %d", length);
- if(length == ERROR_BROKEN_PIPE) {
- SleepEx(0, FALSE);
- continue;
- }
+ else if(length == WAIT_ABANDONED) {
+ /* we are not allowed to process this event, because select_ws
+ is post-processing the signalled events and we must exit. */
+ break;
}
- /* there is some data available, stop waiting */
- logmsg("[select_ws_wait_thread] data available on PIPE: %p", handle);
- break;
}
break;
default:
/* The handle has an unknown type, try to wait on it */
- WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE);
- logmsg("[select_ws_wait_thread] data available on HANDLE: %p", handle);
+ if(WaitForMultipleObjectsEx(2, handles, FALSE, INFINITE, FALSE)
+ == WAIT_OBJECT_0 + 1) {
+ if(WaitForSingleObjectEx(mutex, 0, FALSE) == WAIT_OBJECT_0) {
+ logmsg("[select_ws_wait_thread] data available, HANDLE: %p", handle);
+ SetEvent(signal);
+ ReleaseMutex(mutex);
+ }
+ }
break;
}
return 0;
}
-static HANDLE select_ws_wait(HANDLE handle, HANDLE event)
+static HANDLE select_ws_wait(HANDLE handle, HANDLE signal,
+ HANDLE abort, HANDLE mutex)
{
struct select_ws_wait_data *data;
HANDLE thread = NULL;
@@ -679,7 +724,9 @@ static HANDLE select_ws_wait(HANDLE handle, HANDLE event)
data = malloc(sizeof(struct select_ws_wait_data));
if(data) {
data->handle = handle;
- data->event = event;
+ data->signal = signal;
+ data->abort = abort;
+ data->mutex = mutex;
/* launch waiting thread */
thread = CreateThread(NULL, 0,
@@ -695,21 +742,21 @@ static HANDLE select_ws_wait(HANDLE handle, HANDLE event)
return thread;
}
struct select_ws_data {
- curl_socket_t fd; /* the original input handle (indexed by fds) */
- curl_socket_t wsasock; /* the internal socket handle (indexed by wsa) */
- WSAEVENT wsaevent; /* the internal WINSOCK2 event (indexed by wsa) */
- HANDLE thread; /* the internal threads handle (indexed by thd) */
+ curl_socket_t fd; /* the original input handle (indexed by fds/idx) */
+ curl_socket_t wsasock; /* the internal socket handle (indexed by wsa) */
+ WSAEVENT wsaevent; /* the internal WINSOCK event (indexed by wsa) */
+ HANDLE signal; /* the internal signal handle (indexed by thd) */
+ HANDLE thread; /* the internal thread handle (indexed by thd) */
};
static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, struct timeval *timeout)
{
+ HANDLE abort, mutex, signal, handle, *handles;
DWORD milliseconds, wait, idx;
WSANETWORKEVENTS wsanetevents;
struct select_ws_data *data;
- HANDLE handle, *handles;
WSAEVENT wsaevent;
int error, fds;
- HANDLE waitevent = NULL;
DWORD nfd = 0, thd = 0, wsa = 0;
int ret = 0;
@@ -725,9 +772,17 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
return 0;
}
- /* create internal event to signal waiting threads */
- waitevent = CreateEvent(NULL, TRUE, FALSE, NULL);
- if(!waitevent) {
+ /* create internal event to abort waiting threads */
+ abort = CreateEvent(NULL, TRUE, FALSE, NULL);
+ if(!abort) {
+ errno = ENOMEM;
+ return -1;
+ }
+
+ /* create internal mutex to lock event handling in threads */
+ mutex = CreateMutex(NULL, FALSE, NULL);
+ if(!mutex) {
+ CloseHandle(abort);
errno = ENOMEM;
return -1;
}
@@ -735,7 +790,8 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
/* allocate internal array for the internal data */
data = calloc(nfds, sizeof(struct select_ws_data));
if(data == NULL) {
- CloseHandle(waitevent);
+ CloseHandle(abort);
+ CloseHandle(mutex);
errno = ENOMEM;
return -1;
}
@@ -743,7 +799,8 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
/* allocate internal array for the internal event handles */
handles = calloc(nfds, sizeof(HANDLE));
if(handles == NULL) {
- CloseHandle(waitevent);
+ CloseHandle(abort);
+ CloseHandle(mutex);
free(data);
errno = ENOMEM;
return -1;
@@ -768,10 +825,19 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
data[nfd].fd = curlx_sitosk(fds);
if(fds == fileno(stdin)) {
handle = GetStdHandle(STD_INPUT_HANDLE);
- handle = select_ws_wait(handle, waitevent);
- handles[nfd] = handle;
- data[thd].thread = handle;
- thd++;
+ signal = CreateEvent(NULL, TRUE, FALSE, NULL);
+ if(signal) {
+ handle = select_ws_wait(handle, signal, abort, mutex);
+ if(handle) {
+ handles[nfd] = signal;
+ data[thd].signal = signal;
+ data[thd].thread = handle;
+ thd++;
+ }
+ else {
+ CloseHandle(signal);
+ }
+ }
}
else if(fds == fileno(stdout)) {
handles[nfd] = GetStdHandle(STD_OUTPUT_HANDLE);
@@ -794,10 +860,19 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
curl_socket_t socket = curlx_sitosk(fds);
WSACloseEvent(wsaevent);
handle = (HANDLE) socket;
- handle = select_ws_wait(handle, waitevent);
- handles[nfd] = handle;
- data[thd].thread = handle;
- thd++;
+ signal = CreateEvent(NULL, TRUE, FALSE, NULL);
+ if(signal) {
+ handle = select_ws_wait(handle, signal, abort, mutex);
+ if(handle) {
+ handles[nfd] = signal;
+ data[thd].signal = signal;
+ data[thd].thread = handle;
+ thd++;
+ }
+ else {
+ CloseHandle(signal);
+ }
+ }
}
}
}
@@ -816,8 +891,8 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
/* wait for one of the internal handles to trigger */
wait = WaitForMultipleObjectsEx(nfd, handles, FALSE, milliseconds, FALSE);
- /* signal the event handle for the waiting threads */
- SetEvent(waitevent);
+ /* wait for internal mutex to lock event handling in threads */
+ WaitForSingleObjectEx(mutex, INFINITE, FALSE);
/* loop over the internal handles returned in the descriptors */
for(idx = 0; idx < nfd; idx++) {
@@ -881,6 +956,9 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
}
}
+ /* signal the event handle for the other waiting threads */
+ SetEvent(abort);
+
for(fds = 0; fds < nfds; fds++) {
if(FD_ISSET(fds, readfds))
logmsg("select_ws: %d is readable", fds);
@@ -898,11 +976,13 @@ static int select_ws(int nfds, fd_set *readfds, fd_set *writefds,
}
for(idx = 0; idx < thd; idx++) {
- WaitForSingleObject(data[idx].thread, INFINITE);
+ WaitForSingleObjectEx(data[idx].thread, INFINITE, FALSE);
CloseHandle(data[idx].thread);
+ CloseHandle(data[idx].signal);
}
- CloseHandle(waitevent);
+ CloseHandle(abort);
+ CloseHandle(mutex);
free(handles);
free(data);