Added uart.mitm.

config_templates/system_settings.ini

@@ -52,6 +52,11 @@
 ; Controls whether dns.mitm logs to the sd card for debugging
 ; 0 = Disabled, 1 = Enabled
 ; enable_dns_mitm_debug_log = u8!0x0
+; Controls whether to enable uart mitm
+; for logging bluetooth HCI to btsnoop captures.
+; This is only implemented for [7.0.0+].
+; 0 = Do not enable, 1 = Enable.
+; enable_uart_mitm = u8!0x0
 [hbloader]
 ; Controls the size of the homebrew heap when running as applet.
 ; If set to zero, all available applet memory is used as heap.

libraries/libstratosphere/include/stratosphere/ams/impl/ams_system_thread_definitions.hpp

@@ -109,6 +109,9 @@ namespace ams::impl {
     AMS_DEFINE_SYSTEM_THREAD(21, settings, Main);
     AMS_DEFINE_SYSTEM_THREAD(21, settings, IpcServer);
 
+    /* Bus. */
+    AMS_DEFINE_SYSTEM_THREAD(-12, uart, IpcServer);
+
     /* erpt. */
     AMS_DEFINE_SYSTEM_THREAD(21, erpt, Main);
     AMS_DEFINE_SYSTEM_THREAD(21, erpt, IpcServer);

stratosphere/ams_mitm/source/amsmitm_module_management.cpp

@@ -24,6 +24,7 @@
 #include "ns_mitm/nsmitm_module.hpp"
 #include "dns_mitm/dnsmitm_module.hpp"
 #include "sysupdater/sysupdater_module.hpp"
+#include "uart_mitm/uartmitm_module.hpp"
 
 namespace ams::mitm {
 
@@ -37,6 +38,7 @@ namespace ams::mitm {
             ModuleId_NsMitm,
             ModuleId_DnsMitm,
             ModuleId_Sysupdater,
+            ModuleId_UartMitm,
 
             ModuleId_Count,
         };
@@ -70,6 +72,7 @@ namespace ams::mitm {
             GetModuleDefinition<ns::MitmModule>(),
             GetModuleDefinition<socket::resolver::MitmModule>(),
             GetModuleDefinition<sysupdater::MitmModule>(),
+            GetModuleDefinition<uart::MitmModule>(),
         };
 
     }

stratosphere/ams_mitm/source/set_mitm/settings_sd_kvs.cpp

@@ -362,6 +362,12 @@ namespace ams::settings::fwdbg {
             /* 0 = Disabled, 1 = Enabled */
             R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_dns_mitm_debug_log", "u8!0x0"));
 
+            /* Controls whether to enable uart mitm */
+            /* for logging bluetooth HCI to btsnoop captures. */
+            /* This is only implemented for [7.0.0+]. */
+            /* 0 = Do not enable, 1 = Enable. */
+            R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_uart_mitm", "u8!0x0"));
+
             /* Hbloader custom settings. */
 
             /* Controls the size of the homebrew heap when running as applet. */

stratosphere/ams_mitm/source/uart_mitm/uart_mitm_service.cpp

@@ -0,0 +1,341 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+#include "uart_mitm_service.hpp"
+#include "../amsmitm_debug.hpp"
+#include "../amsmitm_fs_utils.hpp"
+
+/* TODO: This should really use async fs-writing, there's a slowdown with bluetooth communications with current fs-writing. */
+
+namespace ams::mitm::uart {
+
+    /* Helper functions. */
+    bool UartPortService::TryGetCurrentTimestamp(u64 *out) {
+        /* Clear output. */
+        *out = 0;
+
+        /* Check if we have time service. */
+        {
+            bool has_time_service = false;
+            if (R_FAILED(sm::HasService(&has_time_service, sm::ServiceName::Encode("time:s"))) || !has_time_service) {
+                return false;
+            }
+        }
+
+        /* Try to get the current time. */
+        {
+            sm::ScopedServiceHolder<timeInitialize, timeExit> time_holder;
+            return time_holder && R_SUCCEEDED(timeGetCurrentTime(TimeType_LocalSystemClock, out));
+        }
+    }
+
+    UartPortService::UartPortService(const sm::MitmProcessInfo &cl, std::unique_ptr<::UartPortSession> s) : client_info(cl), srv(std::move(s)) {
+        Result rc=0;
+        /* Get a timestamp. */
+        u64 timestamp0, timestamp1;
+        this->TryGetCurrentTimestamp(&timestamp0);
+        timestamp1 = svcGetSystemTick();
+
+        std::snprintf(this->base_path, sizeof(this->base_path), "uart_logs/%011lu_%011lu_%016lx", timestamp0, timestamp1, static_cast<u64>(this->client_info.program_id));
+        ams::mitm::fs::CreateAtmosphereSdDirectory("uart_logs");
+        ams::mitm::fs::CreateAtmosphereSdDirectory(this->base_path);
+
+        char tmp_path[256];
+        std::snprintf(tmp_path, sizeof(tmp_path), "%s/%s", this->base_path, "cmd_log");
+        ams::mitm::fs::CreateAtmosphereSdFile(tmp_path, 0, 0);
+        this->cmdlog_pos = 0;
+
+        this->send_cache_buffer = static_cast<u8 *>(std::malloc(this->CacheBufferSize));
+        if (this->send_cache_buffer != nullptr) {
+            std::memset(this->send_cache_buffer, 0, this->CacheBufferSize);
+        }
+        this->send_cache_pos = 0;
+
+        this->receive_cache_buffer = static_cast<u8 *>(std::malloc(this->CacheBufferSize));
+        if (this->receive_cache_buffer != nullptr) {
+            std::memset(this->receive_cache_buffer, 0, this->CacheBufferSize);
+        }
+        this->receive_cache_pos = 0;
+
+        if (this->send_cache_buffer != nullptr && this->receive_cache_buffer != nullptr) {
+            std::snprintf(tmp_path, sizeof(tmp_path), "%s/%s", this->base_path, "btsnoop_hci.log");
+            ams::mitm::fs::CreateAtmosphereSdFile(tmp_path, 0, 0);
+            rc = ams::mitm::fs::OpenAtmosphereSdFile(&this->datalog_file, tmp_path, FsOpenMode_Read | FsOpenMode_Write | FsOpenMode_Append);
+            this->datalog_ready = R_SUCCEEDED(rc);
+        }
+        this->datalog_pos = 0;
+
+        struct {
+            char id[8];
+            u32 version;
+            u32 datalink_type;
+        } btsnoop_header = { .id = "btsnoop" };
+
+        u32 version = 1;
+        u32 datalink_type = 1002; /* HCI UART (H4) */
+        ams::util::StoreBigEndian(&btsnoop_header.version, version);
+        ams::util::StoreBigEndian(&btsnoop_header.datalink_type, datalink_type);
+
+        this->data_logging_enabled = true;
+        this->WriteLog(&btsnoop_header, sizeof(btsnoop_header));
+        /* This will be re-enabled by WriteUartData once a certain command is detected. */
+        /* If you want to log all HCI traffic during system-boot initialization, you can comment out the below line, however there will be a slowdown. */
+        this->data_logging_enabled = false;
+    }
+
+    void UartPortService::SaveFile(const char *path, const void* buffer, size_t size) {
+        Result rc=0;
+        FsFile file={};
+        char tmp_path[256];
+        std::snprintf(tmp_path, sizeof(tmp_path), "%s/%s", this->base_path, path);
+        ams::mitm::fs::CreateAtmosphereSdFile(tmp_path, 0, 0);
+        rc = ams::mitm::fs::OpenAtmosphereSdFile(&file, tmp_path, FsOpenMode_Read | FsOpenMode_Write | FsOpenMode_Append);
+        if (R_SUCCEEDED(rc)) {
+            rc = fsFileWrite(&file, 0, buffer, size, FsWriteOption_None);
+        }
+        fsFileClose(&file);
+    }
+
+    void UartPortService::WriteCmdLog(const char *str) {
+        Result rc=0;
+        FsFile file={};
+        char tmp_path[256];
+        size_t len = strlen(str);
+        std::snprintf(tmp_path, sizeof(tmp_path), "%s/%s", this->base_path, "cmd_log");
+        rc = ams::mitm::fs::OpenAtmosphereSdFile(&file, tmp_path, FsOpenMode_Read | FsOpenMode_Write | FsOpenMode_Append);
+        if (R_SUCCEEDED(rc)) {
+            rc = fsFileWrite(&file, this->cmdlog_pos, str, len, FsWriteOption_None);
+        }
+        if (R_SUCCEEDED(rc)) {
+            this->cmdlog_pos += len;
+        }
+        fsFileClose(&file);
+    }
+
+    void UartPortService::WriteLog(const void* buffer, size_t size) {
+        if (this->data_logging_enabled && this->datalog_ready) {
+            if (R_SUCCEEDED(fsFileWrite(&this->datalog_file, this->datalog_pos, buffer, size, FsWriteOption_None))) {
+                this->datalog_pos += size;
+            }
+        }
+    }
+
+    void UartPortService::WriteLogPacket(bool dir, const void* buffer, size_t size) {
+        struct {
+            u32 original_length;
+            u32 included_length;
+            u32 packet_flags;
+            u32 cumulative_drops;
+            s64 timestamp_microseconds;
+        } pkt_hdr = {};
+
+        u32 flags = 0;
+        if (dir) {
+            flags |= BIT(0);
+        }
+        ams::util::StoreBigEndian(&pkt_hdr.original_length, static_cast<u32>(size));
+        ams::util::StoreBigEndian(&pkt_hdr.included_length, static_cast<u32>(size));
+        ams::util::StoreBigEndian(&pkt_hdr.packet_flags, flags);
+
+        this->WriteLog(&pkt_hdr, sizeof(pkt_hdr));
+        this->WriteLog(buffer, size);
+    }
+
+    void UartPortService::WriteUartData(bool dir, const void* buffer, size_t size) {
+        u8 *cache_buffer = !dir ? this->send_cache_buffer : this->receive_cache_buffer;
+        size_t *cache_pos = !dir ? &this->send_cache_pos : &this->receive_cache_pos;
+        if (size && *cache_pos + size <= this->CacheBufferSize) {
+            struct {
+                u8 opcode[0x2];
+                u8 param_len;
+            } *hci_cmd = reinterpret_cast<decltype(hci_cmd)>(&cache_buffer[0x1]);
+            static_assert(sizeof(*hci_cmd) == 0x3);
+
+            struct {
+                u8 handle_flags[0x2];
+                u16 data_len;
+            } *hci_acl_data = reinterpret_cast<decltype(hci_acl_data)>(&cache_buffer[0x1]);
+            static_assert(sizeof(*hci_acl_data) == 0x4);
+
+            struct {
+                u8 handle_flags[0x2];
+                u8 data_len;
+            } *hci_sco_data = reinterpret_cast<decltype(hci_sco_data)>(&cache_buffer[0x1]);
+            static_assert(sizeof(*hci_sco_data) == 0x3);
+
+            struct {
+                u8 event_code;
+                u8 param_len;
+            } *hci_event = reinterpret_cast<decltype(hci_event)>(&cache_buffer[0x1]);
+            static_assert(sizeof(*hci_event) == 0x2);
+
+            struct {
+                u8 handle_flags[0x2];
+                u16 data_load_len : 14;
+                u8 rfu1 : 2;
+            } *hci_iso_data = reinterpret_cast<decltype(hci_iso_data)>(&cache_buffer[0x1]);
+            static_assert(sizeof(*hci_iso_data) == 0x4);
+
+            std::memcpy(&cache_buffer[*cache_pos], buffer, size);
+            (*cache_pos)+= size;
+
+            do {
+                size_t orig_pkt_len = 0x0;
+                size_t pkt_len = 0x1;
+                if (cache_buffer[0] == 0x1) {
+                    if (*cache_pos >= 0x1+sizeof(*hci_cmd)) {
+                        orig_pkt_len = sizeof(*hci_cmd) + hci_cmd->param_len;
+                        /* Check for the first cmd used in the port which is opened last. */
+                        if (!this->data_logging_enabled && hci_cmd->opcode[1] == 0xFC && hci_cmd->opcode[0] == 0x16) {
+                            this->data_logging_enabled = true;
+                        }
+                    }
+                }
+                else if (cache_buffer[0] == 0x2) {
+                    if (*cache_pos >= 0x1+sizeof(*hci_acl_data)) {
+                        orig_pkt_len = sizeof(*hci_acl_data) + hci_acl_data->data_len;
+                    }
+                }
+                else if (cache_buffer[0] == 0x3) {
+                    if (*cache_pos >= 0x1+sizeof(*hci_sco_data)) {
+                        orig_pkt_len = sizeof(*hci_sco_data) + hci_sco_data->data_len;
+                    }
+                }
+                else if (cache_buffer[0] == 0x4) {
+                    if (*cache_pos >= 0x1+sizeof(*hci_event)) {
+                        orig_pkt_len = sizeof(*hci_event) + hci_event->param_len;
+                    }
+                }
+                else if (cache_buffer[0] == 0x5) {
+                    if (*cache_pos >= 0x1+sizeof(*hci_iso_data)) {
+                        orig_pkt_len = sizeof(*hci_iso_data) + hci_iso_data->data_load_len;
+                    }
+                }
+                else {
+                    char str[256];
+                    std::snprintf(str, sizeof(str), "WriteUartData(dir = %s): Unknown HCI packet indicator 0x%x, ignoring the packet and emptying the cache.\n", !dir ? "send" : "receive", cache_buffer[0]);
+                    this->WriteCmdLog(str);
+                    *cache_pos = 0;
+                }
+
+                if (orig_pkt_len) {
+                    if (*cache_pos >= 0x1+orig_pkt_len) {
+                        pkt_len+= orig_pkt_len;
+                    }
+                }
+
+                if (pkt_len>0x1) {
+                    this->WriteLogPacket(dir, cache_buffer, pkt_len);
+                    (*cache_pos)-= pkt_len;
+                    if (*cache_pos) {
+                        std::memmove(cache_buffer, &cache_buffer[pkt_len], *cache_pos);
+                    }
+                }
+                else break;
+            } while(*cache_pos);
+        }
+    }
+
+    Result UartPortService::OpenPort(sf::Out<bool> out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, sf::CopyHandle send_handle, sf::CopyHandle receive_handle, u64 send_buffer_length, u64 receive_buffer_length) {
+        Result rc = uartPortSessionOpenPortFwd(this->srv.get(), reinterpret_cast<bool *>(out.GetPointer()), port, baud_rate, flow_control_mode, device_variation, is_invert_tx, is_invert_rx, is_invert_rts, is_invert_cts, send_handle.GetValue(), receive_handle.GetValue(), send_buffer_length, receive_buffer_length);
+        svcCloseHandle(send_handle.GetValue());
+        svcCloseHandle(receive_handle.GetValue());
+
+        char str[256];
+        std::snprintf(str, sizeof(str), "OpenPort(port = 0x%x, baud_rate = %u, flow_control_mode = %u, device_variation = %u, is_invert_tx = %d, is_invert_rx = %d, is_invert_rts = %d, is_invert_cts = %d, send_buffer_length = 0x%lx, receive_buffer_length = 0x%lx): rc = 0x%x, out = %d\n", port, baud_rate, flow_control_mode, device_variation, is_invert_tx, is_invert_rx, is_invert_rts, is_invert_cts, send_buffer_length, receive_buffer_length, rc.GetValue(), out.GetValue());
+        this->WriteCmdLog(str);
+        return rc;
+    }
+
+    Result UartPortService::OpenPortForDev(sf::Out<bool> out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, sf::CopyHandle send_handle, sf::CopyHandle receive_handle, u64 send_buffer_length, u64 receive_buffer_length) {
+        Result rc = uartPortSessionOpenPortForDevFwd(this->srv.get(), reinterpret_cast<bool *>(out.GetPointer()), port, baud_rate, flow_control_mode, device_variation, is_invert_tx, is_invert_rx, is_invert_rts, is_invert_cts, send_handle.GetValue(), receive_handle.GetValue(), send_buffer_length, receive_buffer_length);
+        svcCloseHandle(send_handle.GetValue());
+        svcCloseHandle(receive_handle.GetValue());
+
+        char str[256];
+        std::snprintf(str, sizeof(str), "OpenPortForDev(port = 0x%x, baud_rate = %u, flow_control_mode = %u, device_variation = %u, is_invert_tx = %d, is_invert_rx = %d, is_invert_rts = %d, is_invert_cts = %d, send_buffer_length = 0x%lx, receive_buffer_length = 0x%lx): rc = 0x%x, out = %d\n", port, baud_rate, flow_control_mode, device_variation, is_invert_tx, is_invert_rx, is_invert_rts, is_invert_cts, send_buffer_length, receive_buffer_length, rc.GetValue(), out.GetValue());
+        this->WriteCmdLog(str);
+        return rc;
+    }
+
+    Result UartPortService::GetWritableLength(sf::Out<u64> out) {
+        Result rc = uartPortSessionGetWritableLength(this->srv.get(), reinterpret_cast<u64 *>(out.GetPointer()));
+
+        char str[256];
+        std::snprintf(str, sizeof(str), "GetWritableLength(): rc = 0x%x, out = 0x%lx\n", rc.GetValue(), out.GetValue());
+        this->WriteCmdLog(str);
+
+        return rc;
+    }
+
+    Result UartPortService::Send(sf::Out<u64> out_size, const sf::InAutoSelectBuffer &data) {
+        Result rc = uartPortSessionSend(this->srv.get(), data.GetPointer(), data.GetSize(), reinterpret_cast<u64 *>(out_size.GetPointer()));
+
+        if (R_SUCCEEDED(rc) && out_size.GetValue()) {
+            this->WriteUartData(false, data.GetPointer(), out_size.GetValue());
+        }
+        return rc;
+    }
+
+    Result UartPortService::GetReadableLength(sf::Out<u64> out) {
+        Result rc = uartPortSessionGetReadableLength(this->srv.get(), reinterpret_cast<u64 *>(out.GetPointer()));
+
+        char str[256];
+        std::snprintf(str, sizeof(str), "GetWritableLength(): rc = 0x%x, out = 0x%lx\n", rc.GetValue(), out.GetValue());
+        this->WriteCmdLog(str);
+
+        return rc;
+    }
+
+    Result UartPortService::Receive(sf::Out<u64> out_size, const sf::OutAutoSelectBuffer &data) {
+        Result rc = uartPortSessionReceive(this->srv.get(), data.GetPointer(), data.GetSize(), reinterpret_cast<u64 *>(out_size.GetPointer()));
+
+        if (R_SUCCEEDED(rc) && out_size.GetValue()) {
+            this->WriteUartData(true, data.GetPointer(), out_size.GetValue());
+        }
+        return rc;
+    }
+
+    Result UartPortService::BindPortEvent(sf::Out<bool> out, sf::OutCopyHandle out_event_handle, UartPortEventType port_event_type, s64 threshold) {
+        Result rc = uartPortSessionBindPortEventFwd(this->srv.get(), port_event_type, threshold, reinterpret_cast<bool *>(out.GetPointer()), out_event_handle.GetHandlePointer());
+
+        char str[256];
+        std::snprintf(str, sizeof(str), "BindPortEvent(port_event_type = 0x%x, threshold = 0x%lx): rc = 0x%x, out = %d\n", port_event_type, threshold, rc.GetValue(), out.GetValue());
+        this->WriteCmdLog(str);
+        return rc;
+    }
+
+    Result UartPortService::UnbindPortEvent(sf::Out<bool> out, UartPortEventType port_event_type) {
+        Result rc = uartPortSessionUnbindPortEvent(this->srv.get(), port_event_type, reinterpret_cast<bool *>(out.GetPointer()));
+
+        char str[256];
+        std::snprintf(str, sizeof(str), "UnbindPortEvent(port_event_type = 0x%x): rc = 0x%x, out = %d\n", port_event_type, rc.GetValue(), out.GetValue());
+        this->WriteCmdLog(str);
+
+        return rc;
+    }
+
+    Result UartMitmService::CreatePortSession(sf::Out<std::shared_ptr<impl::IPortSession>> out) {
+        /* Open a port interface. */
+        UartPortSession port;
+        R_TRY(uartCreatePortSessionFwd(this->forward_service.get(), &port));
+        const sf::cmif::DomainObjectId target_object_id{serviceGetObjectId(&port.s)};
+
+        out.SetValue(sf::MakeShared<impl::IPortSession, UartPortService>(this->client_info, std::make_unique<UartPortSession>(port)), target_object_id);
+        return ResultSuccess();
+    }
+
+}

stratosphere/ams_mitm/source/uart_mitm/uart_mitm_service.hpp

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+#include "uart_shim.h"
+
+namespace ams::mitm::uart {
+
+    namespace impl {
+
+        #define AMS_UART_IPORTSESSION_MITM_INTERFACE_INFO(C, H)                                                                                                                             \
+            AMS_SF_METHOD_INFO(C, H, 0, Result, OpenPort,                 (sf::Out<bool> out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, sf::CopyHandle send_handle, sf::CopyHandle receive_handle, u64 send_buffer_length, u64 receive_buffer_length))                     \
+            AMS_SF_METHOD_INFO(C, H, 1, Result, OpenPortForDev,           (sf::Out<bool> out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, sf::CopyHandle send_handle, sf::CopyHandle receive_handle, u64 send_buffer_length, u64 receive_buffer_length))                     \
+            AMS_SF_METHOD_INFO(C, H, 2, Result, GetWritableLength,        (sf::Out<u64> out))                     \
+            AMS_SF_METHOD_INFO(C, H, 3, Result, Send,      (sf::Out<u64> out_size, const sf::InAutoSelectBuffer &data))                     \
+            AMS_SF_METHOD_INFO(C, H, 4, Result, GetReadableLength,        (sf::Out<u64> out))                     \
+            AMS_SF_METHOD_INFO(C, H, 5, Result, Receive,  (sf::Out<u64> out_size, const sf::OutAutoSelectBuffer &data))        \
+            AMS_SF_METHOD_INFO(C, H, 6, Result, BindPortEvent,            (sf::Out<bool> out, sf::OutCopyHandle out_event_handle, UartPortEventType port_event_type, s64 threshold))                     \
+            AMS_SF_METHOD_INFO(C, H, 7, Result, UnbindPortEvent,          (sf::Out<bool> out, UartPortEventType port_event_type))                     \
+
+        AMS_SF_DEFINE_INTERFACE(IPortSession, AMS_UART_IPORTSESSION_MITM_INTERFACE_INFO)
+
+        #define AMS_UART_MITM_INTERFACE_INFO(C, H)                                                                         \
+            AMS_SF_METHOD_INFO(C, H, 6, Result, CreatePortSession, (sf::Out<std::shared_ptr<IPortSession>> out))
+
+        AMS_SF_DEFINE_MITM_INTERFACE(IUartMitmInterface, AMS_UART_MITM_INTERFACE_INFO)
+
+    }
+
+    class UartPortService {
+        private:
+            sm::MitmProcessInfo client_info;
+            std::unique_ptr<::UartPortSession> srv;
+
+            static constexpr inline size_t CacheBufferSize = 0x1000;
+
+            char base_path[256];
+
+            size_t cmdlog_pos;
+            size_t datalog_pos;
+
+            bool datalog_ready;
+            bool data_logging_enabled;
+
+            FsFile datalog_file;
+
+            u8 *send_cache_buffer;
+            u8 *receive_cache_buffer;
+            size_t send_cache_pos;
+            size_t receive_cache_pos;
+
+            bool TryGetCurrentTimestamp(u64 *out);
+            void SaveFile(const char *path, const void* buffer, size_t size);
+            void WriteCmdLog(const char *str);
+            void WriteLog(const void* buffer, size_t size);
+            void WriteLogPacket(bool dir, const void* buffer, size_t size);
+            void WriteUartData(bool dir, const void* buffer, size_t size);
+        public:
+            UartPortService(const sm::MitmProcessInfo &cl, std::unique_ptr<::UartPortSession> s);
+
+            virtual ~UartPortService() {
+                uartPortSessionClose(this->srv.get());
+                fsFileClose(&this->datalog_file);
+                std::free(this->send_cache_buffer);
+                std::free(this->receive_cache_buffer);
+            }
+        public:
+            /* Actual command API. */
+            Result OpenPort(sf::Out<bool> out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, sf::CopyHandle send_handle, sf::CopyHandle receive_handle, u64 send_buffer_length, u64 receive_buffer_length);
+            Result OpenPortForDev(sf::Out<bool> out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, sf::CopyHandle send_handle, sf::CopyHandle receive_handle, u64 send_buffer_length, u64 receive_buffer_length);
+            Result GetWritableLength(sf::Out<u64> out);
+            Result Send(sf::Out<u64> out_size, const sf::InAutoSelectBuffer &data);
+            Result GetReadableLength(sf::Out<u64> out);
+            Result Receive(sf::Out<u64> out_size, const sf::OutAutoSelectBuffer &data);
+            Result BindPortEvent(sf::Out<bool> out, sf::OutCopyHandle out_event_handle, UartPortEventType port_event_type, s64 threshold);
+            Result UnbindPortEvent(sf::Out<bool> out, UartPortEventType port_event_type);
+    };
+    static_assert(impl::IsIPortSession<UartPortService>);
+
+    class UartMitmService : public sf::MitmServiceImplBase {
+        public:
+            using MitmServiceImplBase::MitmServiceImplBase;
+        public:
+            static bool ShouldMitm(const sm::MitmProcessInfo &client_info) {
+                /* We will mitm:
+                 * - bluetooth, for logging HCI.
+                 */
+                return client_info.program_id == ncm::SystemProgramId::Bluetooth;
+            }
+        public:
+            Result CreatePortSession(sf::Out<std::shared_ptr<impl::IPortSession>> out);
+    };
+    static_assert(impl::IsIUartMitmInterface<UartMitmService>);
+
+}

stratosphere/ams_mitm/source/uart_mitm/uart_shim.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <switch.h>
+#include "uart_shim.h"
+
+/* Command forwarders. */
+Result uartCreatePortSessionFwd(Service* s, UartPortSession* out) {
+    return serviceDispatch(s, 6,
+        .out_num_objects = 1,
+        .out_objects = &out->s,
+    );
+}
+
+// [7.0.0+]
+static Result _uartPortSessionOpenPortFwd(UartPortSession* s, bool *out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, Handle send_handle, Handle receive_handle, u64 send_buffer_length, u64 receive_buffer_length, u32 cmd_id) {
+    const struct {
+        u8 is_invert_tx;
+        u8 is_invert_rx;
+        u8 is_invert_rts;
+        u8 is_invert_cts;
+        u32 port;
+        u32 baud_rate;
+        u32 flow_control_mode;
+        u32 device_variation;
+        u32 pad;
+        u64 send_buffer_length;
+        u64 receive_buffer_length;
+    } in = { is_invert_tx!=0, is_invert_rx!=0, is_invert_rts!=0, is_invert_cts!=0, port, baud_rate, flow_control_mode, device_variation, 0, send_buffer_length, receive_buffer_length };
+
+    u8 tmp=0;
+    Result rc = serviceDispatchInOut(&s->s, cmd_id, in, tmp,
+        .in_num_handles = 2,
+        .in_handles = { send_handle, receive_handle },
+    );
+    if (R_SUCCEEDED(rc) && out) *out = tmp & 1;
+    return rc;
+}
+
+Result uartPortSessionOpenPortFwd(UartPortSession* s, bool *out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, Handle send_handle, Handle receive_handle, u64 send_buffer_length, u64 receive_buffer_length) {
+    return _uartPortSessionOpenPortFwd(s, out, port, baud_rate, flow_control_mode, device_variation, is_invert_tx, is_invert_rx, is_invert_rts, is_invert_cts, send_handle, receive_handle, send_buffer_length, receive_buffer_length, 0);
+}
+
+Result uartPortSessionOpenPortForDevFwd(UartPortSession* s, bool *out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, Handle send_handle, Handle receive_handle, u64 send_buffer_length, u64 receive_buffer_length) {
+    return _uartPortSessionOpenPortFwd(s, out, port, baud_rate, flow_control_mode, device_variation, is_invert_tx, is_invert_rx, is_invert_rts, is_invert_cts, send_handle, receive_handle, send_buffer_length, receive_buffer_length, 1);
+}
+
+Result uartPortSessionBindPortEventFwd(UartPortSession* s, UartPortEventType port_event_type, s64 threshold, bool *out, Handle *handle_out) {
+    const struct {
+        u32 port_event_type;
+        u32 pad;
+        u64 threshold;
+    } in = { port_event_type, 0, threshold };
+
+    u8 tmp=0;
+    Result rc = serviceDispatchInOut(&s->s, 6, in, tmp,
+        .out_handle_attrs = { SfOutHandleAttr_HipcCopy },
+        .out_handles = handle_out,
+    );
+    if (R_SUCCEEDED(rc) && out) *out = tmp & 1;
+    return rc;
+}
+

stratosphere/ams_mitm/source/uart_mitm/uart_shim.h

@@ -0,0 +1,23 @@
+/**
+ * @file uart_shim.h
+ * @brief UART IPC wrapper.
+ * @author yellows8
+ * @copyright libnx Authors
+ */
+#pragma once
+#include <switch.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Command forwarders. */
+Result uartCreatePortSessionFwd(Service* s, UartPortSession* out);
+
+Result uartPortSessionOpenPortFwd(UartPortSession* s, bool *out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, Handle send_handle, Handle receive_handle, u64 send_buffer_length, u64 receive_buffer_length);
+Result uartPortSessionOpenPortForDevFwd(UartPortSession* s, bool *out, u32 port, u32 baud_rate, UartFlowControlMode flow_control_mode, u32 device_variation, bool is_invert_tx, bool is_invert_rx, bool is_invert_rts, bool is_invert_cts, Handle send_handle, Handle receive_handle, u64 send_buffer_length, u64 receive_buffer_length);
+Result uartPortSessionBindPortEventFwd(UartPortSession* s, UartPortEventType port_event_type, s64 threshold, bool *out, Handle *handle_out);
+
+#ifdef __cplusplus
+}
+#endif

stratosphere/ams_mitm/source/uart_mitm/uartmitm_module.cpp

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+#include "../amsmitm_initialization.hpp"
+#include "uartmitm_module.hpp"
+#include "uart_mitm_service.hpp"
+
+namespace ams::mitm::uart {
+
+    namespace {
+
+        constexpr sm::ServiceName UartMitmServiceName = sm::ServiceName::Encode("uart");
+
+        struct ServerOptions {
+            static constexpr size_t PointerBufferSize = 0x1000;
+            static constexpr size_t MaxDomains = 0;
+            static constexpr size_t MaxDomainObjects = 0;
+        };
+
+        constexpr size_t MaxServers = 1;
+        constexpr size_t MaxSessions = 10;
+
+        sf::hipc::ServerManager<MaxServers, ServerOptions, MaxSessions> g_server_manager;
+
+        bool ShouldMitmUart() {
+            u8 en = 0;
+            if (settings::fwdbg::GetSettingsItemValue(&en, sizeof(en), "atmosphere", "enable_uart_mitm") == sizeof(en)) {
+                return (en != 0);
+            }
+            return false;
+        }
+    }
+
+    void MitmModule::ThreadFunction(void *arg) {
+        /* The OpenPort cmds had the params changed with 6.x/7.x, so only support 7.x+. */
+        if (hos::GetVersion() < hos::Version_7_0_0) {
+            return;
+        }
+
+        /* Wait until initialization is complete. */
+        mitm::WaitInitialized();
+
+        /* Only use uart-mitm if enabled by the sys-setting. */
+        if (!ShouldMitmUart()) {
+            return;
+        }
+
+        /* Create mitm servers. */
+        R_ABORT_UNLESS((g_server_manager.RegisterMitmServer<impl::IUartMitmInterface, UartMitmService>(UartMitmServiceName)));
+
+        /* Loop forever, servicing our services. */
+        g_server_manager.LoopProcess();
+    }
+
+}

stratosphere/ams_mitm/source/uart_mitm/uartmitm_module.hpp

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+#include "../amsmitm_module.hpp"
+
+namespace ams::mitm::uart {
+
+    DEFINE_MITM_MODULE_CLASS(0x4000, AMS_GET_SYSTEM_THREAD_PRIORITY(uart, IpcServer) - 1);
+
+}