Begin implementation of syscalls.

8 files changed, 117 insertions, 9 deletions

diff --git a/src/kernel/Makefile b/src/kernel/Makefile
index cfaadc3..a8e1c65 100644
--- a/src/kernel/Makefile
+++ b/src/kernel/Makefile
@@ -2,7 +2,7 @@
 OBJ = core/loader.o core/kmain.o core/dbglog.o core/sys.o \
 	core/gdt.o core/idt.o core/interrupt.o core/context_switch.o core/thread.o \
 	core/frame.o core/paging.o core/region.o core/kmalloc.o \
-	user/vfs.o user/nullfs.o user/process.o user/elf.o
+	user/vfs.o user/nullfs.o user/process.o user/elf.o user/syscall.o
 
 LIB = ../common/libc/libc.lib ../common/libkogata/libkogata.lib ../common/libalgo/libalgo.lib
 
diff --git a/src/kernel/core/idt.c b/src/kernel/core/idt.c
index e1862c9..0459a21 100644
--- a/src/kernel/core/idt.c
+++ b/src/kernel/core/idt.c
@@ -4,6 +4,7 @@
 #include <string.h>
 #include <dbglog.h>
 #include <thread.h>
+#include <syscall.h>
 
 struct idt_entry {
 	uint16_t base_lo;		//Low part of address to jump to
@@ -89,7 +90,7 @@ static isr_handler_t irq_handlers[16] = {0};
 static isr_handler_t ex_handlers[32] = {0};
 
 /*	Called in interrupt.s when an exception fires (interrupt 0 to 31) */
-void idt_exHandler(registers_t *regs) {
+void idt_ex_handler(registers_t *regs) {
 	if (ex_handlers[regs->int_no] != 0) {
 		ex_handlers[regs->int_no](regs);
 	} else {
@@ -105,7 +106,7 @@ void idt_exHandler(registers_t *regs) {
 } 
 
 /*	Called in interrupt.s when an IRQ fires (interrupt 32 to 47) */
-void idt_irqHandler(registers_t *regs) {
+void idt_irq_handler(registers_t *regs) {
 	if (regs->err_code > 7) {
 		outb(0xA0, 0x20);
 	}
@@ -117,9 +118,8 @@ void idt_irqHandler(registers_t *regs) {
 }
 
 /* Caled in interrupt.s when a syscall is called */
-void idt_syscallHandler(registers_t *regs) {
-	dbg_printf("Syscall %i (not implemented yet)\n", regs->int_no);
-	// do nothing, yet.
+void idt_syscall_handler(registers_t *regs) {
+	syscall_handler(regs);
 }
 
 /*	For internal use only. Sets up an entry of the IDT with given parameters. */
diff --git a/src/kernel/core/interrupt.s b/src/kernel/core/interrupt.s
index d40fff0..8fb71e8 100644
--- a/src/kernel/core/interrupt.s
+++ b/src/kernel/core/interrupt.s
@@ -1,7 +1,7 @@
 ;************************************************************************************
 
 %macro COMMONSTUB 1
-[EXTERN idt_%1Handler]
+[EXTERN idt_%1_handler]
 %1_common_stub:
 
 	pusha                    ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax
@@ -19,7 +19,7 @@
 	; (passing it directly results in GCC trashing the data when doing optimisations)
 	mov eax, esp
 	push eax
-	call idt_%1Handler
+	call idt_%1_handler
 	add esp, 4
 
 	pop eax        ; reload the original data segment descriptor
diff --git a/src/kernel/core/kmain.c b/src/kernel/core/kmain.c
index 5572ac4..ee6d8b2 100644
--- a/src/kernel/core/kmain.c
+++ b/src/kernel/core/kmain.c
@@ -17,6 +17,7 @@
 #include <nullfs.h>
 #include <process.h>
 #include <elf.h>
+#include <syscall.h>
 
 #include <slab_alloc.h>
 #include <hashtbl.h>
@@ -270,6 +271,8 @@ void kmain(multiboot_info_t *mbd, int32_t mb_magic) {
 	kmalloc_setup();
 	kmalloc_test(kernel_data_end);
 
+	setup_syscalls();
+
 	// enter multi-threading mode
 	// interrupts are enabled at this moment, so all
 	// code run from now on should be preemtible (ie thread-safe)
diff --git a/src/kernel/include/process.h b/src/kernel/include/process.h
index 661aaa6..82ba8dd 100644
--- a/src/kernel/include/process.h
+++ b/src/kernel/include/process.h
@@ -35,15 +35,22 @@ process_t *new_process(process_t *parent);
 // void delete_process(process_t *p);	// TODO define semantics for freeing stuff
 
 pagedir_t *proc_pagedir(process_t *p);
+int proc_pid(process_t *p);
 
 bool start_process(process_t *p, proc_entry_t entry);	// maps a region for user stack
 
 bool proc_add_fs(process_t *p, fs_t *fs, const char* name);
 fs_t *proc_find_fs(process_t *p, const char* name);
+bool proc_rm_fs(process_t *p, const char* name);
 
 bool mmap(process_t *proc, void* addr, size_t size, int mode);		// create empty zone
 bool mmap_file(process_t *proc, fs_handle_t *h, size_t offset, void* addr, size_t size, int mode);
 bool mchmap(process_t *proc, void* addr, int mode);
 bool munmap(process_t *proc, void* addr);
 
+// for syscalls : check that process is authorized to do that
+// (if not, process exits with a segfault)
+void probe_for_read(const void* addr, size_t len);
+void probe_for_write(const void* addr, size_t len);
+
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/syscall.h b/src/kernel/include/syscall.h
new file mode 100644
index 0000000..c6c0ed4
--- /dev/null
+++ b/src/kernel/include/syscall.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <idt.h>
+#include <syscallid.h>
+
+void setup_syscalls();
+
+void syscall_handler(registers_t *regs);
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/user/process.c b/src/kernel/user/process.c
index 0f4892d..579c33d 100644
--- a/src/kernel/user/process.c
+++ b/src/kernel/user/process.c
@@ -118,6 +118,10 @@ pagedir_t *proc_pagedir(process_t *p) {
 	return p->pd;
 }
 
+int proc_pid(process_t *p) {
+	return p->pid;
+}
+
 // ================================== //
 // MANAGING FILESYSTEMS FOR PROCESSES //
 // ================================== //
@@ -143,7 +147,7 @@ fs_t *proc_find_fs(process_t *p, const char* name) {
 // USER MEMORY REGION MANAGEMENT //
 // ============================= //
 
-static user_region_t *find_user_region(process_t *proc, void* addr) {
+static user_region_t *find_user_region(process_t *proc, const void* addr) {
 	for (user_region_t *it = proc->regions; it != 0; it = it->next) {
 		if (addr >= it->addr && addr < it->addr + it->size) return it;
 	}
@@ -287,4 +291,24 @@ static void proc_usermem_pf(void* p, registers_t *regs, void* addr) {
 	}
 }
 
+void probe_for_read(const void* addr, size_t len) {
+	process_t *proc = current_process();
+	user_region_t *r = find_user_region(proc, addr);
+	if (r == 0 || addr + len > r->addr + r->size || !(r->mode & MM_READ)) {
+		dbg_printf("Access violation on read at 0x%p len 0x%p in process %d : exiting.\n",
+			addr, len, proc->pid);
+		exit();
+	}
+}
+
+void probe_for_write(const void* addr, size_t len) {
+	process_t *proc = current_process();
+	user_region_t *r = find_user_region(proc, addr);
+	if (r == 0 || addr + len > r->addr + r->size || !(r->mode & MM_WRITE)) {
+		dbg_printf("Access violation on write at 0x%p len 0x%p in process %d : exiting.\n",
+			addr, len, proc->pid);
+		exit();
+	}
+}
+
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/user/syscall.c b/src/kernel/user/syscall.c
new file mode 100644
index 0000000..563957c
--- /dev/null
+++ b/src/kernel/user/syscall.c
@@ -0,0 +1,64 @@
+#include <string.h>
+#include <process.h>
+#include <vfs.h>
+
+#include <syscall.h>
+
+typedef uint32_t (*syscall_handler_t)(uint32_t, uint32_t, uint32_t, uint32_t, uint32_t);
+
+static syscall_handler_t sc_handlers[SC_MAX] = { 0 };
+
+// ==================== //
+// THE SYSCALLS CODE !! //
+// ==================== //
+
+static uint32_t exit_sc(uint32_t code, uint32_t uu1, uint32_t uu2, uint32_t uu3, uint32_t uu4) {
+	dbg_printf("Proc %d exit with code %d\n", proc_pid(current_process()), code);
+	// TODO : use code... and process exiting is not supposed to be done this way
+
+	exit();
+	return 0;
+}
+
+static uint32_t yield_sc() {
+	yield();
+	return 0;
+}
+
+static uint32_t dbg_print_sc(uint32_t x, uint32_t uu1, uint32_t uu2, uint32_t uu3, uint32_t uu4) {
+	const char* addr = (const char*)x;
+	probe_for_read(addr, 256);
+
+	char buf[256];
+	memcpy(buf, addr, 256);
+	buf[255] = 0;
+
+	dbg_print(buf);
+
+	return 0;
+}
+
+// ====================== //
+// SYSCALLS SETUP ROUTINE //
+// ====================== //
+
+void setup_syscalls() {
+	sc_handlers[SC_EXIT] = exit_sc;
+	sc_handlers[SC_YIELD] = yield_sc;
+	sc_handlers[SC_DBG_PRINT] = dbg_print_sc;
+}
+
+void syscall_handler(registers_t *regs) {
+	ASSERT(regs->int_no == 64);
+
+	if (regs->eax < SC_MAX) {
+		syscall_handler_t h = sc_handlers[regs->eax];
+		if (h != 0) {
+			regs->eax = h(regs->ebx, regs->ecx, regs->edx, regs->esi, regs->edi);
+		} else {
+			regs->eax = -1;
+		}
+	}
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/