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syscall.c File Reference

System Calls. More...

#include <const.h>
#include <arch/i386.h>
#include <arch/mem.h>
#include <kernel/console.h>
#include <kernel/keyboard.h>
#include <kernel/kernel.h>
#include <kernel/speaker.h>
#include <kernel/task.h>
#include <kernel/umalloc.h>
#include <kernel/syscall.h>

Go to the source code of this file.

Data Structures
struct	syscall_t
	System call entry. More...
Defines
#define	SYS_CALL_NR   ( sizeof(syscall_table)/sizeof(dword) )
	Total amount of system calls.
Typedefs
typedef syscall_t	syscall_t
	System call entry.
Functions
void	syscall_handler (dword *eax, dword *ebp)
	This procedure execute every system call invoked by INT 0x80. Parameters: eax  The EAX register of the calling procedure must contains the syscall id. At the end of the syscall it contains the returned value. ebp  The EBP register of the calling procedure. It must point to the stack pointer of the calling procedure.
Variables
syscall_t	syscall_table []
	This is the array of the known system calls.

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Detailed Description

System Calls.

Author:

Andrea Righi <drizzt@inwind.it>

Date:

Last update: 2004-01-03

Note:

Copyright (©) 2003 Andrea Righi

Definition in file syscall.c.

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Define Documentation

#define SYS_CALL_NR   ( sizeof(syscall_table)/sizeof(dword) )

Total amount of system calls. Definition at line 23 of file syscall.c.

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Typedef Documentation

typedef struct syscall_t syscall_t

System call entry.

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Function Documentation

void syscall_handler (  dword *    eax, dword *    ebp )

This procedure execute every system call invoked by INT 0x80. Parameters: eax  The EAX register of the calling procedure must contains the syscall id. At the end of the syscall it contains the returned value. ebp  The EBP register of the calling procedure. It must point to the stack pointer of the calling procedure. Copy the stack parameters from the stack pointer of the calling procedure (pointed by ebp) to the current stack pointer. Then the opportune syscall is invoked. Definition at line 60 of file syscall.c. { // Function pointer. size_t (*p)() = (void *)syscall_table[*eax].address; // How many parameters. int paramcnt = syscall_table[*eax].paramcnt; // Start of parameters'address. size_t *args = (size_t *)(*ebp); register int i; // Check if the system call id does not exceed the syscall table. // NOTE: sycall id is 0-based!!! if ( *eax < SYS_CALL_NR ) { // Pass the parameters to the system call routine. for( i=paramcnt; i; --i) __asm__ __volatile__ ("pushl %0" : : "r"(*(args+i-1))); // Execute the system call. // The result will be returned into the task's eax register. *eax = (*p)(); // Pop elements out of the stack. __asm__ __volatile__ ("add %0, %%esp" : : "r"(paramcnt*sizeof(size_t))); } else { // Invalid syscall id! => kill the task. kprintf("\n\rsyscall: %u", *eax); error("Invalid system call"); } }

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Variable Documentation

syscall_t syscall_table[] [static]

Initial value: { { (size_t)&auto_kill, 1 }, { (size_t)&kgetchar, 0 }, { (size_t)&kputchar, 1 }, { (size_t)&keyb_read, 0 }, { (size_t)&umalloc, 1 }, { (size_t)&ufree, 1 }, } This is the array of the known system calls. Definition at line 35 of file syscall.c.

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