Add WriteFdFmt and clean up more code.

Also say *which* device wasn't found.

Bug: http://b/20666660
Change-Id: I50e234ad89e39ae0a8995083c0b642c61275c5a3
(cherry picked from commit ab52c181fa4c1c9891644635dc5653cda5b90e2b)

14 files changed, 110 insertions, 158 deletions

diff --git a/adb/adb.cpp b/adb/adb.cpp
index 11c65da..8a7b9c9 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -89,10 +89,8 @@ void start_device_log(void) {
     char timestamp[PATH_MAX];
     strftime(timestamp, sizeof(timestamp), "%Y-%m-%d-%H-%M-%S", &now);
 
-    char path[PATH_MAX];
-    snprintf(path, sizeof(path), "/data/adb/adb-%s-%d", timestamp, getpid());
-
-    int fd = unix_open(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0640);
+    std::string path = android::base::StringPrintf("/data/adb/adb-%s-%d", timestamp, getpid());
+    int fd = unix_open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0640);
     if (fd == -1) {
         return;
     }
diff --git a/adb/adb_client.cpp b/adb/adb_client.cpp
index 33eee82..7bb8e4a 100644
--- a/adb/adb_client.cpp
+++ b/adb/adb_client.cpp
@@ -48,7 +48,6 @@ static std::string perror_str(const char* msg) {
 
 static bool ReadProtocolString(int fd, std::string* s, std::string* error) {
     char buf[5];
-
     if (!ReadFdExactly(fd, buf, 4)) {
         *error = perror_str("protocol fault (couldn't read status length)");
         return false;
@@ -154,7 +153,6 @@ static int switch_socket_transport(int fd, std::string* error) {
 
 bool adb_status(int fd, std::string* error) {
     char buf[5];
-
     if (!ReadFdExactly(fd, buf, 4)) {
         *error = perror_str("protocol fault (couldn't read status)");
         return false;
diff --git a/adb/adb_io.cpp b/adb/adb_io.cpp
index c34daf9..5ae6ec3 100644
--- a/adb/adb_io.cpp
+++ b/adb/adb_io.cpp
@@ -16,13 +16,15 @@
 
 #define TRACE_TAG TRACE_RWX
 
-#include "sysdeps.h"
 #include "adb_io.h"
 
 #include <unistd.h>
 
+#include <base/stringprintf.h>
+
 #include "adb_trace.h"
 #include "adb_utils.h"
+#include "sysdeps.h"
 
 bool SendProtocolString(int fd, const std::string& s) {
     int length = s.size();
@@ -30,9 +32,7 @@ bool SendProtocolString(int fd, const std::string& s) {
         length = 0xffff;
     }
 
-    char buf[5];
-    snprintf(buf, sizeof(buf), "%04x", length);
-    return WriteFdExactly(fd, buf, 4) && WriteFdExactly(fd, s);
+    return WriteFdFmt(fd, "%04x", length) && WriteFdExactly(fd, s);
 }
 
 bool SendOkay(int fd) {
@@ -111,6 +111,13 @@ bool WriteFdExactly(int fd, const std::string& str) {
     return WriteFdExactly(fd, str.c_str(), str.size());
 }
 
-bool WriteStringFully(int fd, const char* str) {
-    return WriteFdExactly(fd, str, strlen(str));
+bool WriteFdFmt(int fd, const char* fmt, ...) {
+    std::string str;
+
+    va_list ap;
+    va_start(ap, fmt);
+    android::base::StringAppendV(&str, fmt, ap);
+    va_end(ap);
+
+    return WriteFdExactly(fd, str);
 }
diff --git a/adb/adb_io.h b/adb/adb_io.h
index 3b8b050..8d50a6d 100644
--- a/adb/adb_io.h
+++ b/adb/adb_io.h
@@ -49,11 +49,11 @@ bool ReadFdExactly(int fd, void *buf, size_t len);
  */
 bool WriteFdExactly(int fd, const void* buf, size_t len);
 
-/* Same as above, but with an implicit len = strlen(buf). */
+// Same as above, but for strings.
 bool WriteFdExactly(int fd, const char* s);
 bool WriteFdExactly(int fd, const std::string& s);
 
-// TODO: move minadb off this and remove it.
-bool WriteStringFully(int fd, const char* str);
+// Same as above, but formats the string to send.
+bool WriteFdFmt(int fd, const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3)));
 
 #endif /* ADB_IO_H */
diff --git a/adb/adb_io_test.cpp b/adb/adb_io_test.cpp
index dd09919..8fd5cbf 100644
--- a/adb/adb_io_test.cpp
+++ b/adb/adb_io_test.cpp
@@ -152,3 +152,16 @@ TEST(io, WriteFdExactly_string) {
   ASSERT_TRUE(android::base::ReadFdToString(tf.fd, &s));
   EXPECT_STREQ(str, s.c_str());
 }
+
+TEST(io, WriteFdFmt) {
+    TemporaryFile tf;
+    ASSERT_NE(-1, tf.fd);
+
+    // Test writing a partial string to the file.
+    ASSERT_TRUE(WriteFdFmt(tf.fd, "Foo%s%d", "bar", 123)) << strerror(errno);
+    ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+    std::string s;
+    ASSERT_TRUE(android::base::ReadFdToString(tf.fd, &s));
+    EXPECT_STREQ("Foobar123", s.c_str());
+}
diff --git a/adb/adb_listeners.cpp b/adb/adb_listeners.cpp
index 71a9321..3fc4719 100644
--- a/adb/adb_listeners.cpp
+++ b/adb/adb_listeners.cpp
@@ -185,13 +185,13 @@ void remove_all_listeners(void)
     }
 }
 
-install_status_t install_listener(const char *local_name,
+install_status_t install_listener(const std::string& local_name,
                                   const char *connect_to,
                                   atransport* transport,
                                   int no_rebind)
 {
     for (alistener* l = listener_list.next; l != &listener_list; l = l->next) {
-        if (strcmp(local_name, l->local_name) == 0) {
+        if (local_name == l->local_name) {
             char* cto;
 
             /* can't repurpose a smartsocket */
@@ -226,7 +226,7 @@ install_status_t install_listener(const char *local_name,
         goto nomem;
     }
 
-    listener->local_name = strdup(local_name);
+    listener->local_name = strdup(local_name.c_str());
     if (listener->local_name == nullptr) {
         goto nomem;
     }
@@ -236,9 +236,9 @@ install_status_t install_listener(const char *local_name,
         goto nomem;
     }
 
-    listener->fd = local_name_to_fd(local_name);
+    listener->fd = local_name_to_fd(listener->local_name);
     if (listener->fd < 0) {
-        printf("cannot bind '%s': %s\n", local_name, strerror(errno));
+        printf("cannot bind '%s': %s\n", listener->local_name, strerror(errno));
         free(listener->local_name);
         free(listener->connect_to);
         free(listener);
diff --git a/adb/adb_listeners.h b/adb/adb_listeners.h
index 1d4f062..67168ae 100644
--- a/adb/adb_listeners.h
+++ b/adb/adb_listeners.h
@@ -36,8 +36,8 @@ void listener_disconnect(void*  _l, atransport*  t);
 void listener_event_func(int _fd, unsigned ev, void *_l);
 void ss_listener_event_func(int _fd, unsigned ev, void *_l);
 
-install_status_t install_listener(const char *local_name,
-                                  const char *connect_to,
+install_status_t install_listener(const std::string& local_name,
+                                  const char* connect_to,
                                   atransport* transport,
                                   int no_rebind);
 
diff --git a/adb/adb_main.cpp b/adb/adb_main.cpp
index 5acaf80..bd22d74 100644
--- a/adb/adb_main.cpp
+++ b/adb/adb_main.cpp
@@ -28,6 +28,8 @@
 #include "adb_listeners.h"
 #include "transport.h"
 
+#include <base/stringprintf.h>
+
 #if !ADB_HOST
 #include <getopt.h>
 #include <sys/prctl.h>
@@ -157,16 +159,6 @@ static bool should_drop_privileges() {
 }
 #endif /* ADB_HOST */
 
-/* Constructs a local name of form tcp:port.
- * target_str points to the target string, it's content will be overwritten.
- * target_size is the capacity of the target string.
- * server_port is the port number to use for the local name.
- */
-void build_local_name(char* target_str, size_t target_size, int server_port)
-{
-  snprintf(target_str, target_size, "tcp:%d", server_port);
-}
-
 void start_logging(void)
 {
 #if defined(_WIN32)
@@ -238,9 +230,8 @@ int adb_main(int is_daemon, int server_port)
     local_init(DEFAULT_ADB_LOCAL_TRANSPORT_PORT);
     adb_auth_init();
 
-    char local_name[30];
-    build_local_name(local_name, sizeof(local_name), server_port);
-    if(install_listener(local_name, "*smartsocket*", NULL, 0)) {
+    std::string local_name = android::base::StringPrintf("tcp:%d", server_port);
+    if (install_listener(local_name, "*smartsocket*", NULL, 0)) {
         exit(1);
     }
 #else
@@ -295,15 +286,14 @@ int adb_main(int is_daemon, int server_port)
 
         D("Local port disabled\n");
     } else {
-        char local_name[30];
         if ((root_seclabel != NULL) && (is_selinux_enabled() > 0)) {
             // b/12587913: fix setcon to allow const pointers
             if (setcon((char *)root_seclabel) < 0) {
                 exit(1);
             }
         }
-        build_local_name(local_name, sizeof(local_name), server_port);
-        if(install_listener(local_name, "*smartsocket*", NULL, 0)) {
+        std::string local_name = android::base::StringPrintf("tcp:%d", server_port);
+        if (install_listener(local_name, "*smartsocket*", NULL, 0)) {
             exit(1);
         }
     }
diff --git a/adb/commandline.cpp b/adb/commandline.cpp
index 7964cd3..b385517 100644
--- a/adb/commandline.cpp
+++ b/adb/commandline.cpp
@@ -929,9 +929,7 @@ static int adb_query_command(const std::string& command) {
     return 0;
 }
 
-int adb_commandline(int argc, const char **argv)
-{
-    char buf[4096];
+int adb_commandline(int argc, const char **argv) {
     int no_daemon = 0;
     int is_daemon = 0;
     int is_server = 0;
@@ -1266,6 +1264,7 @@ int adb_commandline(int argc, const char **argv)
     }
     /* adb_command() wrapper commands */
     else if (!strcmp(argv[0], "forward") || !strcmp(argv[0], "reverse")) {
+        std::string cmd;
         char host_prefix[64];
         char reverse = (char) !strcmp(argv[0], "reverse");
         char remove = 0;
@@ -1323,31 +1322,27 @@ int adb_commandline(int argc, const char **argv)
 
         // Implement forward --remove-all
         else if (remove_all) {
-            if (argc != 1)
-                return usage();
-            snprintf(buf, sizeof buf, "%s:killforward-all", host_prefix);
+            if (argc != 1) return usage();
+            cmd = android::base::StringPrintf("%s:killforward-all", host_prefix);
         }
 
         // Implement forward --remove <local>
         else if (remove) {
-            if (argc != 2)
-                return usage();
-            snprintf(buf, sizeof buf, "%s:killforward:%s", host_prefix, argv[1]);
+            if (argc != 2) return usage();
+            cmd = android::base::StringPrintf("%s:killforward:%s", host_prefix, argv[1]);
         }
         // Or implement one of:
         //    forward <local> <remote>
         //    forward --no-rebind <local> <remote>
-        else
-        {
-          if (argc != 3)
-            return usage();
-          const char* command = no_rebind ? "forward:norebind" : "forward";
-          snprintf(buf, sizeof buf, "%s:%s:%s;%s", host_prefix, command, argv[1], argv[2]);
+        else {
+            if (argc != 3) return usage();
+            const char* command = no_rebind ? "forward:norebind" : "forward";
+            cmd = android::base::StringPrintf("%s:%s:%s;%s", host_prefix, command, argv[1], argv[2]);
         }
 
         std::string error;
-        if (adb_command(buf, &error)) {
-            fprintf(stderr,"error: %s\n", error.c_str());
+        if (adb_command(cmd, &error)) {
+            fprintf(stderr, "error: %s\n", error.c_str());
             return 1;
         }
         return 0;
diff --git a/adb/remount_service.cpp b/adb/remount_service.cpp
index 3fb2fcb..87702b0 100644
--- a/adb/remount_service.cpp
+++ b/adb/remount_service.cpp
@@ -90,9 +90,7 @@ static bool remount_partition(int fd, const char* partition, int* ro) {
     return true;
   }
   if (remount(partition, ro)) {
-    char buf[200];
-    snprintf(buf, sizeof(buf), "remount of %s failed: %s\n", partition, strerror(errno));
-    WriteFdExactly(fd, buf);
+    WriteFdFmt(fd, "remount of %s failed: %s\n", partition, strerror(errno));
     return false;
   }
   return true;
@@ -121,14 +119,12 @@ void remount_service(int fd, void* cookie) {
     if (system_verified || vendor_verified) {
         // Allow remount but warn of likely bad effects
         bool both = system_verified && vendor_verified;
-        char buffer[200];
-        snprintf(buffer, sizeof(buffer),
-                 "dm_verity is enabled on the %s%s%s partition%s.\n",
-                 system_verified ? "system" : "",
-                 both ? " and " : "",
-                 vendor_verified ? "vendor" : "",
-                 both ? "s" : "");
-        WriteFdExactly(fd, buffer);
+        WriteFdFmt(fd,
+                   "dm_verity is enabled on the %s%s%s partition%s.\n",
+                   system_verified ? "system" : "",
+                   both ? " and " : "",
+                   vendor_verified ? "vendor" : "",
+                   both ? "s" : "");
         WriteFdExactly(fd,
                        "Use \"adb disable-verity\" to disable verity.\n"
                        "If you do not, remount may succeed, however, you will still "
diff --git a/adb/services.cpp b/adb/services.cpp
index fa5a1a1..1847447 100644
--- a/adb/services.cpp
+++ b/adb/services.cpp
@@ -63,74 +63,54 @@ void *service_bootstrap_func(void *x)
 
 #if !ADB_HOST
 
-void restart_root_service(int fd, void *cookie)
-{
-    char buf[100];
-    char value[PROPERTY_VALUE_MAX];
-
+void restart_root_service(int fd, void *cookie) {
     if (getuid() == 0) {
-        snprintf(buf, sizeof(buf), "adbd is already running as root\n");
-        WriteFdExactly(fd, buf, strlen(buf));
+        WriteFdExactly(fd, "adbd is already running as root\n");
         adb_close(fd);
     } else {
+        char value[PROPERTY_VALUE_MAX];
         property_get("ro.debuggable", value, "");
         if (strcmp(value, "1") != 0) {
-            snprintf(buf, sizeof(buf), "adbd cannot run as root in production builds\n");
-            WriteFdExactly(fd, buf, strlen(buf));
+            WriteFdExactly(fd, "adbd cannot run as root in production builds\n");
             adb_close(fd);
             return;
         }
 
         property_set("service.adb.root", "1");
-        snprintf(buf, sizeof(buf), "restarting adbd as root\n");
-        WriteFdExactly(fd, buf, strlen(buf));
+        WriteFdExactly(fd, "restarting adbd as root\n");
         adb_close(fd);
     }
 }
 
-void restart_unroot_service(int fd, void *cookie)
-{
-    char buf[100];
-
+void restart_unroot_service(int fd, void *cookie) {
     if (getuid() != 0) {
-        snprintf(buf, sizeof(buf), "adbd not running as root\n");
-        WriteFdExactly(fd, buf, strlen(buf));
+        WriteFdExactly(fd, "adbd not running as root\n");
         adb_close(fd);
     } else {
         property_set("service.adb.root", "0");
-        snprintf(buf, sizeof(buf), "restarting adbd as non root\n");
-        WriteFdExactly(fd, buf, strlen(buf));
+        WriteFdExactly(fd, "restarting adbd as non root\n");
         adb_close(fd);
     }
 }
 
-void restart_tcp_service(int fd, void *cookie)
-{
-    char buf[100];
-    char value[PROPERTY_VALUE_MAX];
+void restart_tcp_service(int fd, void *cookie) {
     int port = (int) (uintptr_t) cookie;
-
     if (port <= 0) {
-        snprintf(buf, sizeof(buf), "invalid port\n");
-        WriteFdExactly(fd, buf, strlen(buf));
+        WriteFdFmt(fd, "invalid port %d\n", port);
         adb_close(fd);
         return;
     }
 
+    char value[PROPERTY_VALUE_MAX];
     snprintf(value, sizeof(value), "%d", port);
     property_set("service.adb.tcp.port", value);
-    snprintf(buf, sizeof(buf), "restarting in TCP mode port: %d\n", port);
-    WriteFdExactly(fd, buf, strlen(buf));
+    WriteFdFmt(fd, "restarting in TCP mode port: %d\n", port);
     adb_close(fd);
 }
 
-void restart_usb_service(int fd, void *cookie)
-{
-    char buf[100];
-
+void restart_usb_service(int fd, void *cookie) {
     property_set("service.adb.tcp.port", "0");
-    snprintf(buf, sizeof(buf), "restarting in USB mode\n");
-    WriteFdExactly(fd, buf, strlen(buf));
+    WriteFdExactly(fd, "restarting in USB mode\n");
     adb_close(fd);
 }
 
@@ -143,7 +123,6 @@ static bool reboot_service_impl(int fd, const char* arg) {
         reboot_arg = "sideload";
     }
 
-    char buf[100];
     // It reboots into sideload mode by setting "--sideload" or "--sideload_auto_reboot"
     // in the command file.
     if (strcmp(reboot_arg, "sideload") == 0) {
@@ -174,15 +153,13 @@ static bool reboot_service_impl(int fd, const char* arg) {
     char property_val[PROPERTY_VALUE_MAX];
     int ret = snprintf(property_val, sizeof(property_val), "reboot,%s", reboot_arg);
     if (ret >= static_cast<int>(sizeof(property_val))) {
-        snprintf(buf, sizeof(buf), "reboot string too long. length=%d\n", ret);
-        WriteFdExactly(fd, buf);
+        WriteFdFmt(fd, "reboot string too long: %d\n", ret);
         return false;
     }
 
     ret = property_set(ANDROID_RB_PROPERTY, property_val);
     if (ret < 0) {
-        snprintf(buf, sizeof(buf), "reboot failed: %d\n", ret);
-        WriteFdExactly(fd, buf);
+        WriteFdFmt(fd, "reboot failed: %d\n", ret);
         return false;
     }
 
diff --git a/adb/set_verity_enable_state_service.cpp b/adb/set_verity_enable_state_service.cpp
index d856d57..cc42bc0 100644
--- a/adb/set_verity_enable_state_service.cpp
+++ b/adb/set_verity_enable_state_service.cpp
@@ -27,6 +27,7 @@
 #include "cutils/properties.h"
 
 #include "adb.h"
+#include "adb_io.h"
 #include "ext4_sb.h"
 #include "fs_mgr.h"
 #include "remount_service.h"
@@ -40,18 +41,6 @@ static const bool kAllowDisableVerity = true;
 static const bool kAllowDisableVerity = false;
 #endif
 
-__attribute__((__format__(printf, 2, 3))) __nonnull((2))
-static void write_console(int fd, const char* format, ...)
-{
-    char buffer[256];
-    va_list args;
-    va_start (args, format);
-    vsnprintf (buffer, sizeof(buffer), format, args);
-    va_end (args);
-
-    adb_write(fd, buffer, strnlen(buffer, sizeof(buffer)));
-}
-
 static int get_target_device_size(int fd, const char *blk_device,
                                   uint64_t *device_size)
 {
@@ -63,18 +52,18 @@ static int get_target_device_size(int fd, const char *blk_device,
 
     data_device = adb_open(blk_device, O_RDONLY | O_CLOEXEC);
     if (data_device < 0) {
-        write_console(fd, "Error opening block device (%s)\n", strerror(errno));
+        WriteFdFmt(fd, "Error opening block device (%s)\n", strerror(errno));
         return -1;
     }
 
     if (lseek64(data_device, 1024, SEEK_SET) < 0) {
-        write_console(fd, "Error seeking to superblock\n");
+        WriteFdFmt(fd, "Error seeking to superblock\n");
         adb_close(data_device);
         return -1;
     }
 
     if (adb_read(data_device, &sb, sizeof(sb)) != sizeof(sb)) {
-        write_console(fd, "Error reading superblock\n");
+        WriteFdFmt(fd, "Error reading superblock\n");
         adb_close(data_device);
         return -1;
     }
@@ -98,73 +87,64 @@ static int set_verity_enabled_state(int fd, const char *block_device,
     int retval = -1;
 
     if (make_block_device_writable(block_device)) {
-        write_console(fd, "Could not make block device %s writable (%s).\n",
-                      block_device, strerror(errno));
+        WriteFdFmt(fd, "Could not make block device %s writable (%s).\n",
+                   block_device, strerror(errno));
         goto errout;
     }
 
     device = adb_open(block_device, O_RDWR | O_CLOEXEC);
     if (device == -1) {
-        write_console(fd, "Could not open block device %s (%s).\n",
-                      block_device, strerror(errno));
-        write_console(fd, "Maybe run adb remount?\n");
+        WriteFdFmt(fd, "Could not open block device %s (%s).\n", block_device, strerror(errno));
+        WriteFdFmt(fd, "Maybe run adb remount?\n");
         goto errout;
     }
 
     // find the start of the verity metadata
     if (get_target_device_size(fd, (char*)block_device, &device_length) < 0) {
-        write_console(fd, "Could not get target device size.\n");
+        WriteFdFmt(fd, "Could not get target device size.\n");
         goto errout;
     }
 
     if (lseek64(device, device_length, SEEK_SET) < 0) {
-        write_console(fd,
-                      "Could not seek to start of verity metadata block.\n");
+        WriteFdFmt(fd, "Could not seek to start of verity metadata block.\n");
         goto errout;
     }
 
     // check the magic number
-    if (adb_read(device, &magic_number, sizeof(magic_number))
-             != sizeof(magic_number)) {
-        write_console(fd, "Couldn't read magic number!\n");
+    if (adb_read(device, &magic_number, sizeof(magic_number)) != sizeof(magic_number)) {
+        WriteFdFmt(fd, "Couldn't read magic number!\n");
         goto errout;
     }
 
     if (!enable && magic_number == VERITY_METADATA_MAGIC_DISABLE) {
-        write_console(fd, "Verity already disabled on %s\n", mount_point);
+        WriteFdFmt(fd, "Verity already disabled on %s\n", mount_point);
         goto errout;
     }
 
     if (enable && magic_number == VERITY_METADATA_MAGIC_NUMBER) {
-        write_console(fd, "Verity already enabled on %s\n", mount_point);
+        WriteFdFmt(fd, "Verity already enabled on %s\n", mount_point);
         goto errout;
     }
 
     if (magic_number != VERITY_METADATA_MAGIC_NUMBER
             && magic_number != VERITY_METADATA_MAGIC_DISABLE) {
-        write_console(fd,
-                      "Couldn't find verity metadata at offset %" PRIu64 "!\n",
-                      device_length);
+        WriteFdFmt(fd, "Couldn't find verity metadata at offset %" PRIu64 "!\n", device_length);
         goto errout;
     }
 
     if (lseek64(device, device_length, SEEK_SET) < 0) {
-        write_console(fd,
-                      "Could not seek to start of verity metadata block.\n");
+        WriteFdFmt(fd, "Could not seek to start of verity metadata block.\n");
         goto errout;
     }
 
     if (adb_write(device, &new_magic, sizeof(new_magic)) != sizeof(new_magic)) {
-        write_console(
-            fd, "Could not set verity %s flag on device %s with error %s\n",
-            enable ? "enabled" : "disabled",
-            block_device, strerror(errno));
+        WriteFdFmt(fd, "Could not set verity %s flag on device %s with error %s\n",
+                   enable ? "enabled" : "disabled",
+                   block_device, strerror(errno));
         goto errout;
     }
 
-    write_console(fd, "Verity %s on %s\n",
-                  enable ? "enabled" : "disabled",
-                  mount_point);
+    WriteFdFmt(fd, "Verity %s on %s\n", enable ? "enabled" : "disabled", mount_point);
     retval = 0;
 errout:
     if (device != -1)
@@ -183,14 +163,13 @@ void set_verity_enabled_state_service(int fd, void* cookie)
 
         property_get("ro.secure", propbuf, "0");
         if (strcmp(propbuf, "1")) {
-            write_console(fd, "verity not enabled - ENG build\n");
+            WriteFdFmt(fd, "verity not enabled - ENG build\n");
             goto errout;
         }
 
         property_get("ro.debuggable", propbuf, "0");
         if (strcmp(propbuf, "1")) {
-            write_console(
-                fd, "verity cannot be disabled/enabled - USER build\n");
+            WriteFdFmt(fd, "verity cannot be disabled/enabled - USER build\n");
             goto errout;
         }
 
@@ -200,8 +179,7 @@ void set_verity_enabled_state_service(int fd, void* cookie)
 
         fstab = fs_mgr_read_fstab(fstab_filename);
         if (!fstab) {
-            write_console(fd, "Failed to open %s\nMaybe run adb root?\n",
-                          fstab_filename);
+            WriteFdFmt(fd, "Failed to open %s\nMaybe run adb root?\n", fstab_filename);
             goto errout;
         }
 
@@ -217,12 +195,11 @@ void set_verity_enabled_state_service(int fd, void* cookie)
         }
 
         if (any_changed) {
-            write_console(
-                fd, "Now reboot your device for settings to take effect\n");
+            WriteFdFmt(fd, "Now reboot your device for settings to take effect\n");
         }
     } else {
-        write_console(fd, "%s-verity only works for userdebug builds\n",
-                      enable ? "enable" : "disable");
+        WriteFdFmt(fd, "%s-verity only works for userdebug builds\n",
+                   enable ? "enable" : "disable");
     }
 
 errout:
diff --git a/adb/transport.cpp b/adb/transport.cpp
index b7f30ea..5c50c0a 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -748,7 +748,7 @@ atransport* acquire_one_transport(int state, transport_type ttype,
     int ambiguous = 0;
 
 retry:
-    if (error_out) *error_out = "device not found";
+    if (error_out) *error_out = android::base::StringPrintf("device '%s' not found", serial);
 
     adb_mutex_lock(&transport_lock);
     for (t = transport_list.next; t != &transport_list; t = t->next) {
diff --git a/adb/transport_local.cpp b/adb/transport_local.cpp
index 4d93bb5..b1deffd 100644
--- a/adb/transport_local.cpp
+++ b/adb/transport_local.cpp
@@ -25,6 +25,8 @@
 #include <string.h>
 #include <sys/types.h>
 
+#include <base/stringprintf.h>
+
 #if !ADB_HOST
 #include "cutils/properties.h"
 #endif
@@ -88,7 +90,6 @@ int local_connect(int port) {
 
 int local_connect_arbitrary_ports(int console_port, int adb_port)
 {
-    char buf[64];
     int  fd = -1;
 
 #if ADB_HOST
@@ -105,8 +106,8 @@ int local_connect_arbitrary_ports(int console_port, int adb_port)
         D("client: connected on remote on fd %d\n", fd);
         close_on_exec(fd);
         disable_tcp_nagle(fd);
-        snprintf(buf, sizeof buf, "emulator-%d", console_port);
-        register_socket_transport(fd, buf, adb_port, 1);
+        std::string serial = android::base::StringPrintf("emulator-%d", console_port);
+        register_socket_transport(fd, serial.c_str(), adb_port, 1);
         return 0;
     }
     return -1;