adb: Handle adb connect in a thread

adb connect calls connect() in the event loop. If you pass a wrong ip
address or the server is slow to respond, this will block the event loop
and you can't even kill the adb server with adb kill-server. Handle connect
requests in a service thread instead.

Change-Id: I2ee732869a3dc22a6d3b87cf8ac80acaa7790037

4 files changed, 170 insertions, 122 deletions

diff --git a/adb/adb.c b/adb/adb.c
index 6580c6e..187f51a 100644
--- a/adb/adb.c
+++ b/adb/adb.c
@@ -1387,105 +1387,6 @@ int adb_main(int is_daemon, int server_port)
     return 0;
 }
 
-#if ADB_HOST
-void connect_device(char* host, char* buffer, int buffer_size)
-{
-    int port, fd;
-    char* portstr = strchr(host, ':');
-    char hostbuf[100];
-    char serial[100];
-
-    strncpy(hostbuf, host, sizeof(hostbuf) - 1);
-    if (portstr) {
-        if (portstr - host >= (ptrdiff_t)sizeof(hostbuf)) {
-            snprintf(buffer, buffer_size, "bad host name %s", host);
-            return;
-        }
-        // zero terminate the host at the point we found the colon
-        hostbuf[portstr - host] = 0;
-        if (sscanf(portstr + 1, "%d", &port) == 0) {
-            snprintf(buffer, buffer_size, "bad port number %s", portstr);
-            return;
-        }
-    } else {
-        port = DEFAULT_ADB_LOCAL_TRANSPORT_PORT;
-    }
-
-    snprintf(serial, sizeof(serial), "%s:%d", hostbuf, port);
-    if (find_transport(serial)) {
-        snprintf(buffer, buffer_size, "already connected to %s", serial);
-        return;
-    }
-
-    fd = socket_network_client(hostbuf, port, SOCK_STREAM);
-    if (fd < 0) {
-        snprintf(buffer, buffer_size, "unable to connect to %s:%d", host, port);
-        return;
-    }
-
-    D("client: connected on remote on fd %d\n", fd);
-    close_on_exec(fd);
-    disable_tcp_nagle(fd);
-    register_socket_transport(fd, serial, port, 0);
-    snprintf(buffer, buffer_size, "connected to %s", serial);
-}
-
-void connect_emulator(char* port_spec, char* buffer, int buffer_size)
-{
-    char* port_separator = strchr(port_spec, ',');
-    if (!port_separator) {
-        snprintf(buffer, buffer_size,
-                "unable to parse '%s' as <console port>,<adb port>",
-                port_spec);
-        return;
-    }
-
-    // Zero-terminate console port and make port_separator point to 2nd port.
-    *port_separator++ = 0;
-    int console_port = strtol(port_spec, NULL, 0);
-    int adb_port = strtol(port_separator, NULL, 0);
-    if (!(console_port > 0 && adb_port > 0)) {
-        *(port_separator - 1) = ',';
-        snprintf(buffer, buffer_size,
-                "Invalid port numbers: Expected positive numbers, got '%s'",
-                port_spec);
-        return;
-    }
-
-    /* Check if the emulator is already known.
-     * Note: There's a small but harmless race condition here: An emulator not
-     * present just yet could be registered by another invocation right
-     * after doing this check here. However, local_connect protects
-     * against double-registration too. From here, a better error message
-     * can be produced. In the case of the race condition, the very specific
-     * error message won't be shown, but the data doesn't get corrupted. */
-    atransport* known_emulator = find_emulator_transport_by_adb_port(adb_port);
-    if (known_emulator != NULL) {
-        snprintf(buffer, buffer_size,
-                "Emulator on port %d already registered.", adb_port);
-        return;
-    }
-
-    /* Check if more emulators can be registered. Similar unproblematic
-     * race condition as above. */
-    int candidate_slot = get_available_local_transport_index();
-    if (candidate_slot < 0) {
-        snprintf(buffer, buffer_size, "Cannot accept more emulators.");
-        return;
-    }
-
-    /* Preconditions met, try to connect to the emulator. */
-    if (!local_connect_arbitrary_ports(console_port, adb_port)) {
-        snprintf(buffer, buffer_size,
-                "Connected to emulator on ports %d,%d", console_port, adb_port);
-    } else {
-        snprintf(buffer, buffer_size,
-                "Could not connect to emulator on ports %d,%d",
-                console_port, adb_port);
-    }
-}
-#endif
-
 int handle_host_request(char *service, transport_type ttype, char* serial, int reply_fd, asocket *s)
 {
     atransport *transport = NULL;
@@ -1546,21 +1447,6 @@ int handle_host_request(char *service, transport_type ttype, char* serial, int r
         }
     }
 
-    // add a new TCP transport, device or emulator
-    if (!strncmp(service, "connect:", 8)) {
-        char buffer[4096];
-        char* host = service + 8;
-        if (!strncmp(host, "emu:", 4)) {
-            connect_emulator(host + 4, buffer, sizeof(buffer));
-        } else {
-            connect_device(host, buffer, sizeof(buffer));
-        }
-        // Send response for emulator and device
-        snprintf(buf, sizeof(buf), "OKAY%04x%s",(unsigned)strlen(buffer), buffer);
-        writex(reply_fd, buf, strlen(buf));
-        return 0;
-    }
-
     // remove TCP transport
     if (!strncmp(service, "disconnect:", 11)) {
         char buffer[4096];
diff --git a/adb/adb.h b/adb/adb.h
index 38767e5..622ca70 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -289,7 +289,7 @@ void init_usb_transport(atransport *t, usb_handle *usb, int state);
 void close_usb_devices();
 
 /* cause new transports to be init'd and added to the list */
-void register_socket_transport(int s, const char *serial, int port, int local);
+int register_socket_transport(int s, const char *serial, int port, int local);
 
 /* these should only be used for the "adb disconnect" command */
 void unregister_transport(atransport *t);
diff --git a/adb/services.c b/adb/services.c
index 619199f..d2d428a 100644
--- a/adb/services.c
+++ b/adb/services.c
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <stddef.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -429,6 +430,124 @@ static void wait_for_state(int fd, void* cookie)
     adb_close(fd);
     D("wait_for_state is done\n");
 }
+
+static void connect_device(char* host, char* buffer, int buffer_size)
+{
+    int port, fd;
+    char* portstr = strchr(host, ':');
+    char hostbuf[100];
+    char serial[100];
+    int ret;
+
+    strncpy(hostbuf, host, sizeof(hostbuf) - 1);
+    if (portstr) {
+        if (portstr - host >= (ptrdiff_t)sizeof(hostbuf)) {
+            snprintf(buffer, buffer_size, "bad host name %s", host);
+            return;
+        }
+        // zero terminate the host at the point we found the colon
+        hostbuf[portstr - host] = 0;
+        if (sscanf(portstr + 1, "%d", &port) == 0) {
+            snprintf(buffer, buffer_size, "bad port number %s", portstr);
+            return;
+        }
+    } else {
+        port = DEFAULT_ADB_LOCAL_TRANSPORT_PORT;
+    }
+
+    snprintf(serial, sizeof(serial), "%s:%d", hostbuf, port);
+
+    fd = socket_network_client(hostbuf, port, SOCK_STREAM);
+    if (fd < 0) {
+        snprintf(buffer, buffer_size, "unable to connect to %s:%d", host, port);
+        return;
+    }
+
+    D("client: connected on remote on fd %d\n", fd);
+    close_on_exec(fd);
+    disable_tcp_nagle(fd);
+
+    ret = register_socket_transport(fd, serial, port, 0);
+    if (ret < 0) {
+        adb_close(fd);
+        snprintf(buffer, buffer_size, "already connected to %s", serial);
+    } else {
+        snprintf(buffer, buffer_size, "connected to %s", serial);
+    }
+}
+
+void connect_emulator(char* port_spec, char* buffer, int buffer_size)
+{
+    char* port_separator = strchr(port_spec, ',');
+    if (!port_separator) {
+        snprintf(buffer, buffer_size,
+                "unable to parse '%s' as <console port>,<adb port>",
+                port_spec);
+        return;
+    }
+
+    // Zero-terminate console port and make port_separator point to 2nd port.
+    *port_separator++ = 0;
+    int console_port = strtol(port_spec, NULL, 0);
+    int adb_port = strtol(port_separator, NULL, 0);
+    if (!(console_port > 0 && adb_port > 0)) {
+        *(port_separator - 1) = ',';
+        snprintf(buffer, buffer_size,
+                "Invalid port numbers: Expected positive numbers, got '%s'",
+                port_spec);
+        return;
+    }
+
+    /* Check if the emulator is already known.
+     * Note: There's a small but harmless race condition here: An emulator not
+     * present just yet could be registered by another invocation right
+     * after doing this check here. However, local_connect protects
+     * against double-registration too. From here, a better error message
+     * can be produced. In the case of the race condition, the very specific
+     * error message won't be shown, but the data doesn't get corrupted. */
+    atransport* known_emulator = find_emulator_transport_by_adb_port(adb_port);
+    if (known_emulator != NULL) {
+        snprintf(buffer, buffer_size,
+                "Emulator on port %d already registered.", adb_port);
+        return;
+    }
+
+    /* Check if more emulators can be registered. Similar unproblematic
+     * race condition as above. */
+    int candidate_slot = get_available_local_transport_index();
+    if (candidate_slot < 0) {
+        snprintf(buffer, buffer_size, "Cannot accept more emulators.");
+        return;
+    }
+
+    /* Preconditions met, try to connect to the emulator. */
+    if (!local_connect_arbitrary_ports(console_port, adb_port)) {
+        snprintf(buffer, buffer_size,
+                "Connected to emulator on ports %d,%d", console_port, adb_port);
+    } else {
+        snprintf(buffer, buffer_size,
+                "Could not connect to emulator on ports %d,%d",
+                console_port, adb_port);
+    }
+}
+
+static void connect_service(int fd, void* cookie)
+{
+    char buf[4096];
+    char resp[4096];
+    char *host = cookie;
+
+    if (!strncmp(host, "emu:", 4)) {
+        connect_emulator(host + 4, buf, sizeof(buf));
+    } else {
+        connect_device(host, buf, sizeof(buf));
+    }
+
+    // Send response for emulator and device
+    snprintf(resp, sizeof(resp), "%04x%s",(unsigned)strlen(buf), buf);
+    writex(fd, resp, strlen(resp));
+    adb_close(fd);
+}
 #endif
 
 #if ADB_HOST
@@ -462,6 +581,10 @@ asocket*  host_service_to_socket(const char*  name, const char *serial)
 
         int fd = create_service_thread(wait_for_state, sinfo);
         return create_local_socket(fd);
+    } else if (!strncmp(name, "connect:", 8)) {
+        const char *host = name + 8;
+        int fd = create_service_thread(connect_service, (void *)host);
+        return create_local_socket(fd);
     }
     return NULL;
 }
diff --git a/adb/transport.c b/adb/transport.c
index b4abb66..224fe55 100644
--- a/adb/transport.c
+++ b/adb/transport.c
@@ -32,6 +32,11 @@ static atransport transport_list = {
     .prev = &transport_list,
 };
 
+static atransport pending_list = {
+    .next = &pending_list,
+    .prev = &pending_list,
+};
+
 ADB_MUTEX_DEFINE( transport_lock );
 
 #if ADB_TRACE
@@ -645,8 +650,11 @@ static void transport_registration_func(int _fd, unsigned ev, void *data)
         }
     }
 
-        /* put us on the master device list */
     adb_mutex_lock(&transport_lock);
+    /* remove from pending list */
+    t->next->prev = t->prev;
+    t->prev->next = t->next;
+    /* put us on the master device list */
     t->next = &transport_list;
     t->prev = transport_list.prev;
     t->next->prev = t;
@@ -989,9 +997,10 @@ void close_usb_devices()
 }
 #endif // ADB_HOST
 
-void register_socket_transport(int s, const char *serial, int port, int local)
+int register_socket_transport(int s, const char *serial, int port, int local)
 {
     atransport *t = calloc(1, sizeof(atransport));
+    atransport *n;
     char buff[32];
 
     if (!serial) {
@@ -999,15 +1008,37 @@ void register_socket_transport(int s, const char *serial, int port, int local)
         serial = buff;
     }
     D("transport: %s init'ing for socket %d, on port %d\n", serial, s, port);
-    if ( init_socket_transport(t, s, port, local) < 0 ) {
-        adb_close(s);
+    if (init_socket_transport(t, s, port, local) < 0) {
         free(t);
-        return;
+        return -1;
     }
-    if(serial) {
-        t->serial = strdup(serial);
+
+    adb_mutex_lock(&transport_lock);
+    for (n = pending_list.next; n != &pending_list; n = n->next) {
+        if (n->serial && !strcmp(serial, n->serial)) {
+            adb_mutex_unlock(&transport_lock);
+            free(t);
+            return -1;
+        }
+    }
+
+    for (n = transport_list.next; n != &transport_list; n = n->next) {
+        if (n->serial && !strcmp(serial, n->serial)) {
+            adb_mutex_unlock(&transport_lock);
+            free(t);
+            return -1;
+        }
     }
+
+    t->next = &pending_list;
+    t->prev = pending_list.prev;
+    t->next->prev = t;
+    t->prev->next = t;
+    t->serial = strdup(serial);
+    adb_mutex_unlock(&transport_lock);
+
     register_transport(t);
+    return 0;
 }
 
 #if ADB_HOST
@@ -1077,6 +1108,14 @@ void register_usb_transport(usb_handle *usb, const char *serial, const char *dev
     if(devpath) {
         t->devpath = strdup(devpath);
     }
+
+    adb_mutex_lock(&transport_lock);
+    t->next = &pending_list;
+    t->prev = pending_list.prev;
+    t->next->prev = t;
+    t->prev->next = t;
+    adb_mutex_unlock(&transport_lock);
+
     register_transport(t);
 }