adb: support forwarding TCP port 0.
This CL adds support to forward or reverse TCP port 0 to allow the
system to automatically select an open port. The resolved port number
will be printed to stdout:
$ adb forward tcp:0 tcp:8000
12345
$ adb reverse tcp:0 tcp:9000
23456
This allows testing to be more robust by not hardcoding TCP ports which
may already be in use.
Forwarding port 0 is a host-only change and will work with any device,
but reversing port 0 requires the device to be updated with a new adbd
binary.
This CL also does a little bit of cleanup such as moving the alistener
class out of adb.h, and adds some error checking and additional tests.
Bug: 28051746
Test: python -m unittest discover
Test: adb_test
Test: `adb forward` and `adb reverse` with tcp:0
Change-Id: Icaa87346685b403ab5da7f0e6aa186aa091da572
diff --git a/adb_listeners.cpp b/adb_listeners.cpp
index e8c2338..f54603c 100644
--- a/adb_listeners.cpp
+++ b/adb_listeners.cpp
@@ -20,18 +20,55 @@
#include <stdlib.h>
#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
#include <cutils/sockets.h>
#include "sysdeps.h"
#include "transport.h"
-int gListenAll = 0; /* Not static because it is used in commandline.c. */
+// Not static because it is used in commandline.c.
+int gListenAll = 0;
-static alistener listener_list = {
- .next = &listener_list,
- .prev = &listener_list,
+// A listener is an entity which binds to a local port and, upon receiving a connection on that
+// port, creates an asocket to connect the new local connection to a specific remote service.
+//
+// TODO: some listeners read from the new connection to determine what exact service to connect to
+// on the far side.
+class alistener {
+ public:
+ alistener(const std::string& _local_name, const std::string& _connect_to);
+ ~alistener();
+
+ fdevent fde;
+ int fd = -1;
+
+ std::string local_name;
+ std::string connect_to;
+ atransport* transport = nullptr;
+ adisconnect disconnect;
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(alistener);
};
+alistener::alistener(const std::string& _local_name, const std::string& _connect_to)
+ : local_name(_local_name), connect_to(_connect_to) {
+}
+
+alistener::~alistener() {
+ // Closes the corresponding fd.
+ fdevent_remove(&fde);
+
+ if (transport) {
+ transport->RemoveDisconnect(&disconnect);
+ }
+}
+
+// listener_list retains ownership of all created alistener objects. Removing an alistener from
+// this list will cause it to be deleted.
+typedef std::list<std::unique_ptr<alistener>> ListenerList;
+static ListenerList& listener_list = *new ListenerList();
+
static void ss_listener_event_func(int _fd, unsigned ev, void *_l) {
if (ev & FDE_READ) {
sockaddr_storage ss;
@@ -73,7 +110,7 @@
s = create_local_socket(fd);
if (s) {
s->transport = listener->transport;
- connect_to_remote(s, listener->connect_to);
+ connect_to_remote(s, listener->connect_to.c_str());
return;
}
@@ -81,66 +118,63 @@
}
}
-static void free_listener(alistener* l)
-{
- if (l->next) {
- l->next->prev = l->prev;
- l->prev->next = l->next;
- l->next = l->prev = l;
- }
-
- // closes the corresponding fd
- fdevent_remove(&l->fde);
-
- if (l->local_name)
- free((char*)l->local_name);
-
- if (l->connect_to)
- free((char*)l->connect_to);
-
- if (l->transport) {
- l->transport->RemoveDisconnect(&l->disconnect);
- }
- free(l);
-}
-
+// Called as a transport disconnect function. |arg| is the raw alistener*.
static void listener_disconnect(void* arg, atransport*) {
- alistener* listener = reinterpret_cast<alistener*>(arg);
- listener->transport = nullptr;
- free_listener(listener);
-}
-
-static int local_name_to_fd(const char* name, std::string* error) {
- if (!strncmp("tcp:", name, 4)) {
- int port = atoi(name + 4);
- if (gListenAll > 0) {
- return network_inaddr_any_server(port, SOCK_STREAM, error);
- } else {
- return network_loopback_server(port, SOCK_STREAM, error);
+ for (auto iter = listener_list.begin(); iter != listener_list.end(); ++iter) {
+ if (iter->get() == arg) {
+ (*iter)->transport = nullptr;
+ listener_list.erase(iter);
+ return;
}
}
+}
+
+int local_name_to_fd(alistener* listener, int* resolved_tcp_port, std::string* error) {
+ if (android::base::StartsWith(listener->local_name, "tcp:")) {
+ int requested_port = atoi(&listener->local_name[4]);
+ int sock = -1;
+ if (gListenAll > 0) {
+ sock = network_inaddr_any_server(requested_port, SOCK_STREAM, error);
+ } else {
+ sock = network_loopback_server(requested_port, SOCK_STREAM, error);
+ }
+
+ // If the caller requested port 0, update the listener name with the resolved port.
+ if (sock >= 0 && requested_port == 0) {
+ int local_port = adb_socket_get_local_port(sock);
+ if (local_port > 0) {
+ listener->local_name = android::base::StringPrintf("tcp:%d", local_port);
+ if (resolved_tcp_port != nullptr) {
+ *resolved_tcp_port = local_port;
+ }
+ }
+ }
+
+ return sock;
+ }
#if !defined(_WIN32) // No Unix-domain sockets on Windows.
- // It's nonsensical to support the "reserved" space on the adb host side
- if (!strncmp(name, "local:", 6)) {
- return network_local_server(name + 6,
- ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM, error);
- } else if (!strncmp(name, "localabstract:", 14)) {
- return network_local_server(name + 14,
- ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM, error);
- } else if (!strncmp(name, "localfilesystem:", 16)) {
- return network_local_server(name + 16,
- ANDROID_SOCKET_NAMESPACE_FILESYSTEM, SOCK_STREAM, error);
+ // It's nonsensical to support the "reserved" space on the adb host side.
+ if (android::base::StartsWith(listener->local_name, "local:")) {
+ return network_local_server(&listener->local_name[6], ANDROID_SOCKET_NAMESPACE_ABSTRACT,
+ SOCK_STREAM, error);
+ } else if (android::base::StartsWith(listener->local_name, "localabstract:")) {
+ return network_local_server(&listener->local_name[14], ANDROID_SOCKET_NAMESPACE_ABSTRACT,
+ SOCK_STREAM, error);
+ } else if (android::base::StartsWith(listener->local_name, "localfilesystem:")) {
+ return network_local_server(&listener->local_name[16], ANDROID_SOCKET_NAMESPACE_FILESYSTEM,
+ SOCK_STREAM, error);
}
#endif
- *error = android::base::StringPrintf("unknown local portname '%s'", name);
+ *error = android::base::StringPrintf("unknown local portname '%s'",
+ listener->local_name.c_str());
return -1;
}
// Write the list of current listeners (network redirections) into a string.
std::string format_listeners() {
std::string result;
- for (alistener* l = listener_list.next; l != &listener_list; l = l->next) {
+ for (auto& l : listener_list) {
// Ignore special listeners like those for *smartsocket*
if (l->connect_to[0] == '*') {
continue;
@@ -149,65 +183,51 @@
// Entries from "adb reverse" have no serial.
android::base::StringAppendF(&result, "%s %s %s\n",
l->transport->serial ? l->transport->serial : "(reverse)",
- l->local_name, l->connect_to);
+ l->local_name.c_str(), l->connect_to.c_str());
}
return result;
}
-InstallStatus remove_listener(const char *local_name, atransport* transport) {
- alistener *l;
-
- for (l = listener_list.next; l != &listener_list; l = l->next) {
- if (!strcmp(local_name, l->local_name)) {
- free_listener(l);
+InstallStatus remove_listener(const char* local_name, atransport* transport) {
+ for (auto iter = listener_list.begin(); iter != listener_list.end(); ++iter) {
+ if (local_name == (*iter)->local_name) {
+ listener_list.erase(iter);
return INSTALL_STATUS_OK;
}
}
return INSTALL_STATUS_LISTENER_NOT_FOUND;
}
-void remove_all_listeners(void)
-{
- alistener *l, *l_next;
- for (l = listener_list.next; l != &listener_list; l = l_next) {
- l_next = l->next;
+void remove_all_listeners() {
+ auto iter = listener_list.begin();
+ while (iter != listener_list.end()) {
// Never remove smart sockets.
- if (l->connect_to[0] == '*')
- continue;
- free_listener(l);
+ if ((*iter)->connect_to[0] == '*') {
+ ++iter;
+ } else {
+ iter = listener_list.erase(iter);
+ }
}
}
-InstallStatus install_listener(const std::string& local_name,
- const char *connect_to,
- atransport* transport,
- int no_rebind,
- std::string* error)
-{
- for (alistener* l = listener_list.next; l != &listener_list; l = l->next) {
+InstallStatus install_listener(const std::string& local_name, const char* connect_to,
+ atransport* transport, int no_rebind, int* resolved_tcp_port,
+ std::string* error) {
+ for (auto& l : listener_list) {
if (local_name == l->local_name) {
- char* cto;
-
- /* can't repurpose a smartsocket */
+ // Can't repurpose a smartsocket.
if(l->connect_to[0] == '*') {
*error = "cannot repurpose smartsocket";
return INSTALL_STATUS_INTERNAL_ERROR;
}
- /* can't repurpose a listener if 'no_rebind' is true */
+ // Can't repurpose a listener if 'no_rebind' is true.
if (no_rebind) {
*error = "cannot rebind";
return INSTALL_STATUS_CANNOT_REBIND;
}
- cto = strdup(connect_to);
- if(cto == 0) {
- *error = "cannot duplicate string";
- return INSTALL_STATUS_INTERNAL_ERROR;
- }
-
- free((void*) l->connect_to);
- l->connect_to = cto;
+ l->connect_to = connect_to;
if (l->transport != transport) {
l->transport->RemoveDisconnect(&l->disconnect);
l->transport = transport;
@@ -217,54 +237,29 @@
}
}
- alistener* listener = reinterpret_cast<alistener*>(
- calloc(1, sizeof(alistener)));
- if (listener == nullptr) {
- goto nomem;
- }
+ std::unique_ptr<alistener> listener(new alistener(local_name, connect_to));
- listener->local_name = strdup(local_name.c_str());
- if (listener->local_name == nullptr) {
- goto nomem;
- }
-
- listener->connect_to = strdup(connect_to);
- if (listener->connect_to == nullptr) {
- goto nomem;
- }
-
- listener->fd = local_name_to_fd(listener->local_name, error);
+ listener->fd = local_name_to_fd(listener.get(), resolved_tcp_port, error);
if (listener->fd < 0) {
- free(listener->local_name);
- free(listener->connect_to);
- free(listener);
return INSTALL_STATUS_CANNOT_BIND;
}
close_on_exec(listener->fd);
- if (!strcmp(listener->connect_to, "*smartsocket*")) {
- fdevent_install(&listener->fde, listener->fd, ss_listener_event_func,
- listener);
+ if (listener->connect_to == "*smartsocket*") {
+ fdevent_install(&listener->fde, listener->fd, ss_listener_event_func, listener.get());
} else {
- fdevent_install(&listener->fde, listener->fd, listener_event_func,
- listener);
+ fdevent_install(&listener->fde, listener->fd, listener_event_func, listener.get());
}
fdevent_set(&listener->fde, FDE_READ);
- listener->next = &listener_list;
- listener->prev = listener_list.prev;
- listener->next->prev = listener;
- listener->prev->next = listener;
listener->transport = transport;
if (transport) {
- listener->disconnect.opaque = listener;
+ listener->disconnect.opaque = listener.get();
listener->disconnect.func = listener_disconnect;
transport->AddDisconnect(&listener->disconnect);
}
- return INSTALL_STATUS_OK;
-nomem:
- fatal("cannot allocate listener");
- return INSTALL_STATUS_INTERNAL_ERROR;
+ listener_list.push_back(std::move(listener));
+ return INSTALL_STATUS_OK;
}