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#include "types.h"
#include "stat.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "defs.h"
#include "x86.h"
#include "traps.h"
#include "syscall.h"
#include "spinlock.h"
#include "buf.h"
#include "fs.h"
#include "fsvar.h"
#include "elf.h"
#include "file.h"
#include "fcntl.h"
// User code makes a system call with INT T_SYSCALL.
// System call number in %eax.
// Arguments on the stack, from the user call to the C
// library system call function. The saved user %esp points
// to a saved program counter, and then the first argument.
// Fetch the int at addr from process p.
int
fetchint(struct proc *p, uint addr, int *ip)
{
if(addr >= p->sz || addr+4 > p->sz)
return -1;
*ip = *(int*)(p->mem + addr);
return 0;
}
// Fetch the nul-terminated string at addr from process p.
// Doesn't actually copy the string - just sets *pp to point at it.
// Returns length of string, not including nul.
int
fetchstr(struct proc *p, uint addr, char **pp)
{
char *cp, *ep;
if(addr >= p->sz)
return -1;
*pp = p->mem + addr;
ep = p->mem + p->sz;
for(cp = *pp; cp < ep; cp++)
if(*cp == 0)
return cp - *pp;
return -1;
}
// Fetch the argno'th word-sized system call argument as an integer.
int
argint(int argno, int *ip)
{
struct proc *p = curproc[cpu()];
return fetchint(p, p->tf->esp + 4 + 4*argno, ip);
}
// Fetch the nth word-sized system call argument as a pointer
// to a block of memory of size n bytes. Check that the pointer
// lies within the process address space.
int
argptr(int argno, char **pp, int size)
{
int i;
struct proc *p = curproc[cpu()];
if(argint(argno, &i) < 0)
return -1;
if((uint)i >= p->sz || (uint)i+size >= p->sz)
return -1;
*pp = p->mem + i;
return 0;
}
// Fetch the nth word-sized system call argument as a string pointer.
// Check that the pointer is valid and the string is nul-terminated.
// (There is no shared writable memory, so the string can't change
// between this check and being used by the kernel.)
int
argstr(int argno, char **pp)
{
int addr;
if(argint(argno, &addr) < 0)
return -1;
return fetchstr(curproc[cpu()], addr, pp);
}
extern int sys_chdir(void);
extern int sys_close(void);
extern int sys_dup(void);
extern int sys_exec(void);
extern int sys_exit(void);
extern int sys_fork(void);
extern int sys_fstat(void);
extern int sys_getpid(void);
extern int sys_kill(void);
extern int sys_link(void);
extern int sys_mkdir(void);
extern int sys_mknod(void);
extern int sys_open(void);
extern int sys_pipe(void);
extern int sys_read(void);
extern int sys_sbrk(void);
extern int sys_unlink(void);
extern int sys_wait(void);
extern int sys_write(void);
void
syscall(void)
{
struct proc *cp = curproc[cpu()];
int num = cp->tf->eax;
int ret = -1;
switch(num){
case SYS_fork:
ret = sys_fork();
break;
case SYS_exit:
ret = sys_exit();
break;
case SYS_wait:
ret = sys_wait();
break;
case SYS_pipe:
ret = sys_pipe();
break;
case SYS_write:
ret = sys_write();
break;
case SYS_read:
ret = sys_read();
break;
case SYS_close:
ret = sys_close();
break;
case SYS_kill:
ret = sys_kill();
break;
case SYS_exec:
ret = sys_exec();
break;
case SYS_open:
ret = sys_open();
break;
case SYS_mknod:
ret = sys_mknod();
break;
case SYS_unlink:
ret = sys_unlink();
break;
case SYS_fstat:
ret = sys_fstat();
break;
case SYS_link:
ret = sys_link();
break;
case SYS_mkdir:
ret = sys_mkdir();
break;
case SYS_chdir:
ret = sys_chdir();
break;
case SYS_dup:
ret = sys_dup();
break;
case SYS_getpid:
ret = sys_getpid();
break;
case SYS_sbrk:
ret = sys_sbrk();
break;
default:
cprintf("unknown sys call %d\n", num);
// Maybe kill the process?
break;
}
cp->tf->eax = ret;
}
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