Store size of message in buffer

Makefile

@@ -28,16 +28,16 @@ debug: os.iso kernel/kernel.elf
 	@$(EMU) -s $(QFLAGS) &
 	@$(GDB) -ex "target remote localhost:1234" -ex "symbol-file kernel/kernel.elf"
 
-os.iso: kernel/kernel.elf initrd/* initrd/init initrd/vfs
+os.iso: kernel/kernel.elf init vfs initrd/*
 	@cp kernel/kernel.elf iso/boot
 	@cd initrd; tar -f ../iso/boot/initrd.tar -c *
 	@grub-mkrescue -o $@ iso
 
-initrd/init: init/* kernel/start.o
+init: init/* kernel/start.o
 	@cd init && make
 	@cp init/init initrd/init
 
-initrd/vfs: vfs/* kernel/start.o
+vfs: vfs/* kernel/start.o
 	@cd vfs && make
 	@cp vfs/vfs initrd/vfs
 

init/main.c

@@ -88,13 +88,18 @@ int main(char* initrd, uint32_t initrd_sz) {
     vga_write_string("Loaded VFS into memory, creating task\n");
     createTaskCr3((void*)header.entry,cr3);
     vga_write_string("Created VFS task, sending test message\n");
-    send_msg(2,"hi",3);
+    send_msg(2,"hello",6);
     vga_write_string("Sent test message, yielding to task\n");
     yield();
     vga_write_string("Yielded and got control, getting message\n");
-    int sender=&sender;
+    int sender;
-    char* msg=get_msg(&sender);
+    int size;
-    vga_write_string("Message: ");
+    char* msg=get_msg(&sender,&size);
+    vga_write_string("Message of size ");
+    char str[256];
+    int_to_ascii(size,str);
+    vga_write_string(str);
+    vga_write_string(": ");
     vga_write_string(msg);
     vga_write_string("\n");
   }

kernel/cpu/i386/isr.c

@@ -186,7 +186,7 @@ void isr_handler(registers_t r) {
       } else if (r.eax==5) {
         r.ebx=(uint32_t)tasking_get_errno_address();
       } else if (r.eax==6) {
-        r.ebx=(uint32_t)tasking_get_msg((uint32_t*)r.ebx);
+        r.ebx=(uint32_t)tasking_get_msg((uint32_t*)r.ebx,(uint32_t*)r.ecx);
       } else if (r.eax==7) {
         tasking_send_msg(r.ebx,(void*)r.ecx,r.edx);
       } else if (r.eax==8) {

kernel/cpu/i386/tasking.c

@@ -120,6 +120,7 @@ void tasking_send_msg(uint32_t pid,char* msg,uint32_t size) {
       }
       task->msg_store[task->wr]=data;
       task->sender_store[task->wr]=currentTask->pid;
+      task->size_store[task->wr]=size;
       task->wr++;
       if (task->wr==16) {
         task->wr=0;
@@ -135,7 +136,7 @@ void tasking_send_msg(uint32_t pid,char* msg,uint32_t size) {
   }
 }
 
-void* tasking_get_msg(uint32_t* sender) {
+void* tasking_get_msg(uint32_t* sender,uint32_t* size) {
   if (!currentTask->msg_store) {
     return NULL;
   }
@@ -153,6 +154,7 @@ void* tasking_get_msg(uint32_t* sender) {
     }
   }
   *sender=currentTask->sender_store[currentTask->rd];
+  *size=currentTask->size_store[currentTask->rd];
   char* data=currentTask->msg_store[currentTask->rd];
   currentTask->msg_store[currentTask->rd]=NULL;
   currentTask->sender_store[currentTask->rd]=0;

kernel/cpu/i386/tasking.h

@@ -14,6 +14,7 @@ typedef struct Task {
   uint32_t pid;
   char* msg_store[16];
   uint32_t sender_store[16];
+  uint32_t size_store[16];
   uint8_t rd;
   uint8_t wr;
   struct Task* next;

kernel/cpu/tasking.h

@@ -10,5 +10,5 @@ Task* tasking_createTask(void* eip);
 Task* tasking_createTaskCr3(void* eip,void* cr3);
 char isPrivleged(uint32_t pid);
 void tasking_send_msg(uint32_t pid,char* msg,uint32_t size);
-void* tasking_get_msg(uint32_t* sender);
+void* tasking_get_msg(uint32_t* sender,uint32_t* size);
 #endif

libc/tasking.c

@@ -14,12 +14,12 @@ void createTask(void* task) {
   "::"b"(task));
 }
 
-void* get_msg(uint32_t* sender) {
+void* get_msg(uint32_t* sender,uint32_t* size) {
   void* msg;
   asm volatile("  \
     mov $6, %%eax; \
     int $80; \
-  ":"=b"(msg):"b"(sender));
+  ":"=b"(msg):"b"(sender),"c"(size));
   return msg;
 }
 

sysroot/usr/include/tasking.h

@@ -9,6 +9,6 @@ void createTaskCr3(void* task,void* cr3);
 void createTaskCr3Param(void* task,void* cr3,uint32_t param1,uint32_t param2);
 char isPrivleged(uint32_t pid);
 void send_msg(uint32_t pid,void* msg,uint32_t size);
-void* get_msg(uint32_t* sender);
+void* get_msg(uint32_t* sender,uint32_t* size);
 
 #endif

vfs/main.c

@@ -1,9 +1,10 @@
 #include <tasking.h>
 
 int main() {
-  int sender=&sender;
+  int sender;
-  char* msg=get_msg(&sender);
+  int size;
-  send_msg(1,msg,3);
+  char* msg=get_msg(&sender,&size);
+  send_msg(1,msg,size);
   yield();
   for (;;);
 }