Commit b50263f7 authored by Nick Mathewson's avatar Nick Mathewson 🎨
Browse files

More work on task #43: fix race conditions on multithreaded (win32) servers.


svn:r3251
parent 15543a62
......@@ -331,6 +331,7 @@ tor_socketpair(int family, int type, int protocol, int fd[2])
}
fd[0] = connector;
fd[1] = acceptor;
return 0;
abort_tidy_up_and_fail:
......@@ -557,6 +558,11 @@ get_uname(void)
/** Minimalist interface to run a void function in the background. On
* unix calls fork, on win32 calls beginthread. Returns -1 on failure.
* func should not return, but rather should call spawn_exit.
*
* NOTE: if <b>data</b> is used, it should not be allocated on the stack,
* since in a multithreaded environment, there is no way to be sure that
* the caller's stack will still be around when the called function is
* running.
*/
int
spawn_func(int (*func)(void *), void *data)
......
......@@ -213,8 +213,9 @@ static int cpuworker_main(void *data) {
#ifndef TOR_IS_MULTITHREADED
tor_close_socket(fdarray[0]); /* this is the side of the socketpair the parent uses */
connection_free_all(); /* so the child doesn't hold the parent's fd's open */
#endif
handle_signals(0); /* ignore interrupts from the keyboard, etc */
#endif
tor_free(data);
dup_onion_keys(&onion_key, &last_onion_key);
......@@ -270,33 +271,38 @@ static int cpuworker_main(void *data) {
/** Launch a new cpuworker.
*/
static int spawn_cpuworker(void) {
int fd[2];
int *fdarray;
int fd;
connection_t *conn;
if (tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0) {
fdarray = tor_malloc(sizeof(int)*2);
if (tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fdarray) < 0) {
log(LOG_ERR, "Couldn't construct socketpair: %s",
tor_socket_strerror(tor_socket_errno(-1)));
tor_cleanup();
tor_free(fdarray);
exit(1);
}
spawn_func(cpuworker_main, (void*)fd);
fd = fdarray[0];
spawn_func(cpuworker_main, (void*)fdarray);
log_fn(LOG_DEBUG,"just spawned a worker.");
#ifndef TOR_IS_MULTITHREADED
tor_close_socket(fd[1]); /* we don't need the worker's side of the pipe */
tor_close_socket(fdarray[1]); /* we don't need the worker's side of the pipe */
tor_free(fdarray);
#endif
conn = connection_new(CONN_TYPE_CPUWORKER);
set_socket_nonblocking(fd[0]);
set_socket_nonblocking(fd);
/* set up conn so it's got all the data we need to remember */
conn->s = fd[0];
conn->s = fd;
conn->address = tor_strdup("localhost");
if (connection_add(conn) < 0) { /* no space, forget it */
log_fn(LOG_WARN,"connection_add failed. Giving up.");
connection_free(conn); /* this closes fd[0] */
connection_free(conn); /* this closes fd */
return -1;
}
......
......@@ -618,6 +618,7 @@ int connection_dns_process_inbuf(connection_t *conn) {
void dnsworkers_rotate(void)
{
connection_t *dnsconn;
log_fn(LOG_INFO, "Rotating DNS workers.");
while ((dnsconn = connection_get_by_type_state(CONN_TYPE_DNSWORKER,
DNSWORKER_STATE_IDLE))) {
connection_mark_for_close(dnsconn);
......@@ -653,17 +654,21 @@ static int dnsworker_main(void *data) {
int fd;
int result;
/* log_fn(LOG_NOTICE,"After spawn: fdarray @%d has %d:%d", (int)fdarray, fdarray[0],fdarray[1]); */
fd = fdarray[1]; /* this side is ours */
#ifndef TOR_IS_MULTITHREADED
tor_close_socket(fdarray[0]); /* this is the side of the socketpair the parent uses */
connection_free_all(); /* so the child doesn't hold the parent's fd's open */
#endif
handle_signals(0); /* ignore interrupts from the keyboard, etc */
#endif
tor_free(data);
for (;;) {
if (recv(fd, &address_len, 1, 0) != 1) {
log_fn(LOG_INFO,"dnsworker exiting because tor process closed connection (either pruned idle dnsworker or died).");
log_fn(LOG_INFO,"Error on %d was %s", fd, tor_socket_strerror(tor_socket_errno(fd)));
spawn_exit();
}
......@@ -704,33 +709,40 @@ static int dnsworker_main(void *data) {
/** Launch a new DNS worker; return 0 on success, -1 on failure.
*/
static int spawn_dnsworker(void) {
int fd[2];
int *fdarray;
int fd;
connection_t *conn;
if (tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0) {
fdarray = tor_malloc(sizeof(int)*2);
if (tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fdarray) < 0) {
log(LOG_ERR, "Couldn't construct socketpair: %s",
tor_socket_strerror(tor_socket_errno(-1)));
tor_cleanup();
tor_free(fdarray);
exit(1);
}
spawn_func(dnsworker_main, (void*)fd);
/* log_fn(LOG_NOTICE,"Before spawn: fdarray @%d has %d:%d", (int)fdarray, fdarray[0],fdarray[1]); */
fd = fdarray[0]; /* We copy this out here, since dnsworker_main may free fdarray */
spawn_func(dnsworker_main, (void*)fdarray);
log_fn(LOG_DEBUG,"just spawned a worker.");
#ifndef TOR_IS_MULTITHREADED
tor_close_socket(fd[1]); /* we don't need the worker's side of the pipe */
tor_close_socket(fdarray[1]); /* we don't need the worker's side of the pipe */
tor_free(fdarray);
#endif
conn = connection_new(CONN_TYPE_DNSWORKER);
set_socket_nonblocking(fd[0]);
set_socket_nonblocking(fd);
/* set up conn so it's got all the data we need to remember */
conn->s = fd[0];
conn->s = fd;
conn->address = tor_strdup("<unused>");
if (connection_add(conn) < 0) { /* no space, forget it */
log_fn(LOG_WARN,"connection_add failed. Giving up.");
connection_free(conn); /* this closes fd[0] */
connection_free(conn); /* this closes fd */
return -1;
}
......
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