BSD 的proc是只读的？ --只是不能用 echo >

hello_proc.c:

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#include
#include



static int procfs_dotest(PFS_FILL_ARGS)
{
   int error=0;  
  const char *pp;
          
            
   if (uio == NULL)
       {
           printf("NULL Pointer\n");
        return (EOPNOTSUPP);
    }
    
    printf("Check Operation\n");
     if (uio->uio_rw == UIO_READ)
    {  
        printf("read\n");
        sbuf_printf(sb, "cur pid: %ld\n", (long)td->td_proc->p_pid);
    }
    else
    {        
        printf("write\n");
        sbuf_trim(sb);
        sbuf_finish(sb);
        pp = sbuf_data(sb);
        printf("In: %s\n",pp);
                 
    }         
   return (error);
}

static int procfstest_attr(PFS_ATTR_ARGS)
{

    /* XXX inefficient, split into separate functions */
        vap->va_mode = 0666;
        return 0;
}

static int procfstest_init(PFS_INIT_ARGS)
{
    struct pfs_node *root;
    
    root = pi->pi_root;
    pfs_create_file(root, "dotest", &procfs_dotest,
        procfstest_attr, NULL, NULL, PFS_RDWR|PFS_RAWWR);
     return 0;
}

static int
procfstest_uninit(PFS_INIT_ARGS)
{
     /* nothing to do, pseudofs will GC */
    return (0);
}

PSEUDOFS(procfstest, 1);
MODULE_DEPEND(procfstest, procfs, 1, 1, 1);



Makefile:

##################################################
# Note: It is important to make sure you include
# the makefile after declaring the KMOD and SRCS variables.
 
# Declare Name of kernel module
KMOD    =  hello_proc
 
# Enumerate Source files for kernel module
SRCS    =  hello_proc.c vnode_if.h
 
# Include kernel module makefile
.include
##################################################

P.S.:
BSD的PROC接口不要用echo xxx>proc的方式访问，会告诉你
Operation not supported

 /* we don't support locking */
 if ((mode & O_SHLOCK) || (mode & O_EXLOCK))
        PFS_RETURN (EOPNOTSUPP);