linux 的 sys_read 在哪里定义？

声明:syscalls.h

 asmlinkage long sys_read(unsigned int fd, char __user *buf, size_t count);

定义:

 

syscalls.h

C/C++ code

    
    
    
    

     
     
     
     #define
     
     
     
      SYSCALL_DEFINEx(x, name, ...) \
     
     
     
      asmlinkage 
     
     
     
     long
     
     
     
      sys##name(__SC_DECL##x(__VA_ARGS__))
    
    
    
    

fs/read_write.c

C/C++ code

    
    
    
    

     
     
     
     SYSCALL_DEFINE3(read, unsigned 
     
     
     
     int
     
     
     
     , fd, 
     
     
     
     char
     
     
     
      __user 
     
     
     
     *
     
     
     
     , buf, size_t, count) { 
     
     
     
     struct
     
     
     
      file 
     
     
     
     *
     
     
     
     file; ssize_t ret 
     
     
     
     =
     
     
     
      
     
     
     
     -
     
     
     
     EBADF; 
     
     
     
     int
     
     
     
      fput_needed; file 
     
     
     
     =
     
     
     
      fget_light(fd, 
     
     
     
     &
     
     
     
     fput_needed); 
     
     
     
     if
     
     
     
      (file) { loff_t pos 
     
     
     
     =
     
     
     
      file_pos_read(file); ret 
     
     
     
     =
     
     
     
      vfs_read(file, buf, count, 
     
     
     
     &
     
     
     
     pos); file_pos_write(file, pos); fput_light(file, fput_needed); } 
     
     
     
     return
     
     
     
      ret; }