os-xv6/kernel/syscall.c

#include "types.h"
#include "param.h"
#include "memlayout.h"
#include "riscv.h"
#include "spinlock.h"
#include "proc.h"
#include "syscall.h"
#include "defs.h"

// Fetch the uint64 at addr from the current process.
int
fetchaddr(uint64 addr, uint64 *ip)
{
  struct proc *p = myproc();
  if(addr >= p->sz || addr+sizeof(uint64) > p->sz) // both tests needed, in case of overflow
    return -1;
  if(copyin(p->pagetable, (char *)ip, addr, sizeof(*ip)) != 0)
    return -1;
  return 0;
}

// Fetch the nul-terminated string at addr from the current process.
// Returns length of string, not including nul, or -1 for error.
int
fetchstr(uint64 addr, char *buf, int max)
{
  struct proc *p = myproc();
  if(copyinstr(p->pagetable, buf, addr, max) < 0)
    return -1;
  return strlen(buf);
}

static uint64
argraw(int n)
{
  struct proc *p = myproc();
  switch (n) {
  case 0:
    return p->trapframe->a0;
  case 1:
    return p->trapframe->a1;
  case 2:
    return p->trapframe->a2;
  case 3:
    return p->trapframe->a3;
  case 4:
    return p->trapframe->a4;
  case 5:
    return p->trapframe->a5;
  }
  panic("argraw");
  return -1;
}

// Fetch the nth 32-bit system call argument.
void
argint(int n, int *ip)
{
  *ip = argraw(n);
}

// Retrieve an argument as a pointer.
// Doesn't check for legality, since
// copyin/copyout will do that.
void
argaddr(int n, uint64 *ip)
{
  *ip = argraw(n);
}

// Fetch the nth word-sized system call argument as a null-terminated string.
// Copies into buf, at most max.
// Returns string length if OK (including nul), -1 if error.
int
argstr(int n, char *buf, int max)
{
  uint64 addr;
  argaddr(n, &addr);
  return fetchstr(addr, buf, max);
}

// Prototypes for the functions that handle system calls.
extern uint64 sys_fork(void);
extern uint64 sys_exit(void);
extern uint64 sys_wait(void);
extern uint64 sys_pipe(void);
extern uint64 sys_read(void);
extern uint64 sys_kill(void);
extern uint64 sys_exec(void);
extern uint64 sys_fstat(void);
extern uint64 sys_chdir(void);
extern uint64 sys_dup(void);
extern uint64 sys_getpid(void);
extern uint64 sys_sbrk(void);
extern uint64 sys_sleep(void);
extern uint64 sys_uptime(void);
extern uint64 sys_open(void);
extern uint64 sys_write(void);
extern uint64 sys_mknod(void);
extern uint64 sys_unlink(void);
extern uint64 sys_link(void);
extern uint64 sys_mkdir(void);
extern uint64 sys_close(void);
extern uint64 sys_sysinfo(void);  // 新增
extern uint64 sys_trace(void);

// An array mapping syscall numbers from syscall.h
// to the function that handles the system call.
static uint64 (*syscalls[])(void) = {
[SYS_fork]    sys_fork,
[SYS_exit]    sys_exit,
[SYS_wait]    sys_wait,
[SYS_pipe]    sys_pipe,
[SYS_read]    sys_read,
[SYS_kill]    sys_kill,
[SYS_exec]    sys_exec,
[SYS_fstat]   sys_fstat,
[SYS_chdir]   sys_chdir,
[SYS_dup]     sys_dup,
[SYS_getpid]  sys_getpid,
[SYS_sbrk]    sys_sbrk,
[SYS_sleep]   sys_sleep,
[SYS_uptime]  sys_uptime,
[SYS_open]    sys_open,
[SYS_write]   sys_write,
[SYS_mknod]   sys_mknod,
[SYS_unlink]  sys_unlink,
[SYS_link]    sys_link,
[SYS_mkdir]   sys_mkdir,
[SYS_close]   sys_close,
[SYS_sysinfo] sys_sysinfo,
[SYS_trace]   sys_trace
};

// 在文件开头、syscalls数组前添加（顺序需与syscall.h中的调用号一致）
static char *syscall_names[] = {
  "",          // 0号未使用
  "fork",      // 1: SYS_fork
  "exit",      // 2: SYS_exit
  "wait",      // 3: SYS_wait
  "pipe",      // 4: SYS_pipe
  "read",      // 5: SYS_read
  "kill",      // 6: SYS_kill
  "exec",      // 7: SYS_exec
  "fstat",     // 8: SYS_fstat
  "chdir",     // 9: SYS_chdir
  "dup",       // 10: SYS_dup
  "getpid",    // 11: SYS_getpid
  "sbrk",      // 12: SYS_sbrk
  "sleep",     // 13: SYS_sleep
  "uptime",    // 14: SYS_uptime
  "open",      // 15: SYS_open
  "write",     // 16: SYS_write
  "mknod",     // 17: SYS_mknod
  "unlink",    // 18: SYS_unlink
  "link",      // 19: SYS_link
  "mkdir",     // 20: SYS_mkdir
  "close",     // 21: SYS_close
  "trace",      // 22: SYS_trace（新增，需与SYS_trace编号一致）
  "sysinfo"    // 23: SYS_sysinfo
};



void
syscall(void)
{
  int num;
  struct proc *p = myproc();
  

  num = p->trapframe->a7;
  if(num > 0 && num < NELEM(syscalls) && syscalls[num]) {
    // Use num to lookup the system call function for num, call it,
    // and store its return value in p->trapframe->a0
    p->trapframe->a0 = syscalls[num]();
    if (strlen(p->mask) > 0 && p->mask[num] == '1'){
	    p->trace_counts[num]++;
	    printf("%d: syscall %s(trace counts: %d) -> %d\n", p->pid, syscall_names[num], p->trace_counts[num], p->trapframe->a0);
    }
  } else {
    printf("%d %s: unknown sys call %d\n",
            p->pid, p->name, num);
    p->trapframe->a0 = -1;
  }
}