本文介绍了在FreeBSD内核模块中读取文本文件的例子的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

任何人都可以给一些简单的例子(函数名称是好的)在一个FreeBSD内核模块中从一个给定的目录逐行读取文本文件(二进制文件确实是好的)?

真的很感谢你的帮助。

解决方案

etc / motd on load:

  //内核模块motd catter。 
// Doug Luce [email protected]

#include< sys / param.h>
#include< sys / vnode.h>
#include< sys / fcntl.h>
#include< sys / module.h>
#include< sys / kernel.h>
#include< sys / namei.h>
#include< sys / proc.h>
#include< sys / sbuf.h>

static int catfile(const char * filename){
struct sbuf * sb;
static char buf [128];
struct nameidata nd;
off_t ofs;
ssize_t resid;
int错误,flags,len;

NDINIT(& nd,LOOKUP,FOLLOW,UIO_SYSSPACE,filename,curthread);
标志= FREAD;
error = vn_open(& nd,& flags,0,NULL);
if(error)
return(error);

NDFREE(& nd,NDF_ONLY_PNBUF);

ofs = 0;
len = sizeof(buf) - 1;
sb = sbuf_new_auto();
while(1){
error = vn_rdwr(UIO_READ,nd.ni_vp,buf,len,ofs,
UIO_SYSSPACE,IO_NODELOCKED,curthread-> td_ucred,
NOCRED,& ; resid,curthread);
if(error)
break;
if(resid == len)
break;
buf [len - resid] = 0;
sbuf_printf(sb,%s,buf);
ofs + = len - resid;
}

VOP_UNLOCK(nd.ni_vp,0);
vn_close(nd.ni_vp,FREAD,curthread-> td_ucred,curthread);
uprintf(%s,sbuf_data(sb));
返回0;

$ b静态int EventHandler(struct module inModule,int inEvent,void * inArg){
switch(inEvent){
case MOD_LOAD:
uprintf(MOTD module loading.\
);
if(catfile(/ etc / motd)!= 0)
uprintf(Error read MOTD.\\\
);
返回0;
case MOD_UNLOAD:
uprintf(MOTD module unloading.\\\
);
返回0;
默认值:
返回EOPNOTSUPP;



static moduledata_t moduleData = {
motd_kmod,
EventHandler,
NULL
};

DECLARE_MODULE(motd_kmod,moduleData,SI_SUB_DRIVERS,SI_ORDER_MIDDLE);

主要来自

没有很好的扫描/解析工具,原生的内核端,所以
通常很困难。


Could anyone give some simple examples (function names are good) for reading text files line by line (binary is OK if text is really hard) in a FreeBSD kernel module, from a given directory?

Really appreciate your kind help.

解决方案

Here's a sample kernel module that'll cat your /etc/motd on load:

// kernel module motd catter.
// Doug Luce [email protected]

#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/module.h>
#include <sys/kernel.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/sbuf.h>

static int catfile(const char *filename) {
  struct sbuf *sb;
  static char buf[128];
  struct nameidata nd;
  off_t ofs;
  ssize_t resid;
  int error, flags, len;

  NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, curthread);
  flags = FREAD;
  error = vn_open(&nd, &flags, 0, NULL);
  if (error)
    return (error);

  NDFREE(&nd, NDF_ONLY_PNBUF);

  ofs = 0;
  len = sizeof(buf) - 1;
  sb = sbuf_new_auto();
  while (1) {
    error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
                    UIO_SYSSPACE, IO_NODELOCKED, curthread->td_ucred,
                    NOCRED, &resid, curthread);
    if (error)
      break;
    if (resid == len)
      break;
    buf[len - resid] = 0;
    sbuf_printf(sb, "%s", buf);
    ofs += len - resid;
  }

  VOP_UNLOCK(nd.ni_vp, 0);
  vn_close(nd.ni_vp, FREAD, curthread->td_ucred, curthread);
  uprintf("%s", sbuf_data(sb));
  return 0;
}

static int EventHandler(struct module *inModule, int inEvent, void *inArg) {
  switch (inEvent) {
  case MOD_LOAD:
    uprintf("MOTD module loading.\n");
    if (catfile("/etc/motd") != 0)
      uprintf("Error reading MOTD.\n");
    return 0;
  case MOD_UNLOAD:
    uprintf("MOTD module unloading.\n");
    return 0;
  default:
    return EOPNOTSUPP;
  }
}

static moduledata_t  moduleData = {
  "motd_kmod",
  EventHandler,
  NULL
};

DECLARE_MODULE(motd_kmod, moduleData, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);

This was cobbled together mostly from bits of https://svnweb.freebsd.org/base/release/10.1.0/sys/kern/vfs_mountroot.c?revision=274417&view=markup

There's no nice scanning/parsing facilities native kernel-side, sothat's usually done the hard way.

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09-24 21:04