From 70ef8c0af557738510805ba4d8b8b4bda3902f4a Mon Sep 17 00:00:00 2001
From: Leon Schuermann <leon@is.currently.online>
Date: Thu, 9 May 2024 17:50:38 -0400
Subject: [PATCH] libtock/ipc: add custom IPC service callback type with buffer
 pointer

---
 examples/rot13_service/main.c          | 4 ++--
 examples/services/ble-env-sense/main.c | 2 +-
 examples/tutorials/05_ipc/led/main.c   | 2 +-
 examples/tutorials/05_ipc/rng/main.c   | 2 +-
 libtock-sync/services/unit_test.c      | 6 +++---
 libtock/kernel/ipc.c                   | 4 ++--
 libtock/kernel/ipc.h                   | 7 ++++++-
 7 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/examples/rot13_service/main.c b/examples/rot13_service/main.c
index be33ac289..519962370 100644
--- a/examples/rot13_service/main.c
+++ b/examples/rot13_service/main.c
@@ -6,8 +6,8 @@ struct rot13_buf {
   char buf[31];
 };
 
-static void rot13_callback(int pid, int len, int buf, __attribute__ ((unused)) void* ud) {
-  struct rot13_buf *rb = (struct rot13_buf*)buf;
+static void rot13_callback(int pid, int len, void *buf, __attribute__ ((unused)) void* ud) {
+  struct rot13_buf *rb = buf;
   int length = rb->length;
   if (length > len - 1) {
     length = len - 1;
diff --git a/examples/services/ble-env-sense/main.c b/examples/services/ble-env-sense/main.c
index 1c26dea76..00b16dd4f 100644
--- a/examples/services/ble-env-sense/main.c
+++ b/examples/services/ble-env-sense/main.c
@@ -94,7 +94,7 @@ typedef struct {
 } sensor_update_t;
 
 
-static void ipc_callback(int pid, int len, int buf, __attribute__ ((unused)) void* ud) {
+static void ipc_callback(int pid, int len, void *buf, __attribute__ ((unused)) void* ud) {
   if (len < (int) sizeof(sensor_update_t)) {
     printf("Error! IPC message too short.\n");
     ipc_notify_client(pid);
diff --git a/examples/tutorials/05_ipc/led/main.c b/examples/tutorials/05_ipc/led/main.c
index 735d83afc..65fae6e60 100644
--- a/examples/tutorials/05_ipc/led/main.c
+++ b/examples/tutorials/05_ipc/led/main.c
@@ -16,7 +16,7 @@
 
 uint8_t _number_of_leds = 0;
 
-static void ipc_callback(int pid, int len, int buf, __attribute__ ((unused)) void* ud) {
+static void ipc_callback(int pid, int len, void *buf, __attribute__ ((unused)) void* ud) {
   uint8_t* buffer = (uint8_t*) buf;
 
   if (len < 1) {
diff --git a/examples/tutorials/05_ipc/rng/main.c b/examples/tutorials/05_ipc/rng/main.c
index aa38c76ca..c439cfc6f 100644
--- a/examples/tutorials/05_ipc/rng/main.c
+++ b/examples/tutorials/05_ipc/rng/main.c
@@ -18,7 +18,7 @@
 // If the buffer is not long enough to hold the number of requested bytes
 // the service will stop processing the request and not notify the client.
 
-static void ipc_callback(int pid, int len, int buf, __attribute__ ((unused)) void* ud) {
+static void ipc_callback(int pid, int len, void *buf, __attribute__ ((unused)) void* ud) {
   uint8_t* buffer = (uint8_t*) buf;
   uint8_t* rng;
 
diff --git a/libtock-sync/services/unit_test.c b/libtock-sync/services/unit_test.c
index b4fbe195f..15740740f 100644
--- a/libtock-sync/services/unit_test.c
+++ b/libtock-sync/services/unit_test.c
@@ -351,14 +351,14 @@ static void timeout_callback(__attribute__ ((unused)) uint32_t now,
  */
 static void unit_test_service_callback(int                            pid,
                                        __attribute__ ((unused)) int   len,
-                                       int                            buf,
+                                       void*                          buf,
                                        __attribute__ ((unused)) void *ud) {
   if (buf == 0) {
     return;
   }
 
-  unit_test_t *test      = (unit_test_t *)buf;
-  linked_list_t *pending = (linked_list_t *)ud;
+  unit_test_t *test      = buf;
+  linked_list_t *pending = ud;
 
   switch (test->cmd) {
     case TestInit:
diff --git a/libtock/kernel/ipc.c b/libtock/kernel/ipc.c
index e798d9c88..42f6c268f 100644
--- a/libtock/kernel/ipc.c
+++ b/libtock/kernel/ipc.c
@@ -18,14 +18,14 @@ int ipc_discover(const char* pkg_name, size_t* svc_id) {
 }
 
 int ipc_register_service_callback(const char *pkg_name,
-                                  subscribe_upcall callback, void *ud) {
+                                  ipc_service_upcall callback, void *ud) {
   size_t svc_id;
 
   // Look up the service id so we can subscribe as the service
   int ret = ipc_discover(pkg_name, &svc_id);
   if (ret < 0) return ret;
 
-  subscribe_return_t sval = subscribe(IPC_DRIVER_NUM, svc_id, callback, ud);
+  subscribe_return_t sval = subscribe(IPC_DRIVER_NUM, svc_id, *((subscribe_upcall*) &callback), ud);
   return tock_subscribe_return_to_returncode(sval);
 }
 
diff --git a/libtock/kernel/ipc.h b/libtock/kernel/ipc.h
index 1c3db78c3..ecc061a8a 100644
--- a/libtock/kernel/ipc.h
+++ b/libtock/kernel/ipc.h
@@ -11,6 +11,11 @@ extern "C" {
 
 #define IPC_DRIVER_NUM 0x10000
 
+// Specific upcall type used for IPC service callbacks. This upcall
+// has a pointer as its third argument, which contains the address to
+// the buffer that an app has shared.
+typedef void (ipc_service_upcall)(int, int, void*, void*);
+
 // Performs service discovery
 //
 // Retrieves the process identifier of the process with the given package name,
@@ -26,7 +31,7 @@ int ipc_discover(const char* pkg_name, size_t* svc_id);
 //   callback  - the address callback function to execute when clients notify
 //   void* ud  - `userdata`. data passed to callback function
 int ipc_register_service_callback(const char *pkg_name,
-                                  subscribe_upcall callback, void *ud);
+                                  ipc_service_upcall callback, void *ud);
 
 // Registers a client callback for a particular service.
 //