转 Linux内核 Ps模块

时间：2014-04-10 21:24:32 阅读：667 评论：0 收藏：0 [点我收藏+]

ricky_proc.c源码:
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/thread_info.h>
#include <linux/list.h>
#include <linux/sched.h>

#define MODULE_VERSION "1.0"
#define MODULE_NAME "ricky_proc_info_final"
#define P_MAX_LEN 30
#define ARRAYMAX 4096

static struct proc_dir_entry *ricky_file, *ricky_dir;
static char c[ARRAYMAX];

static int proc_read_info(char *page,char **start,off_t off,int count, int *eof,void *data)
{
    int len=0;
    char *c = (char *)ricky_file->data;
    len=sprintf(page,"%s\n",c);
    return len;
}

static int __init ricky_info_init(void)
{
    //get_current() is defined to current
    //so we could get a task by "current"
    struct task_struct *task_c;
    task_c = current;
    struct task_struct *p;
    struct list_head *pos;
    int count=0;

    int rv=0;
    //create proc directory
    ricky_dir = proc_mkdir(MODULE_NAME, NULL);
    if(ricky_dir==NULL){
        rv=-ENOMEM;
        goto out;
    }
    ricky_dir->owner = THIS_MODULE;
    //create proc file
    ricky_file=create_proc_entry("rickyps",0644,ricky_dir);
    if(ricky_file==NULL){
        rv=-ENOMEM;
        goto no_rickyps;
    }
    //traversal of task_list
    int length=0;
    int l=0;
    list_for_each(pos, &task_c->tasks){

        //get the list_entry
        p=list_entry(pos, struct task_struct, tasks);
        count++;
        if(count==1){
            length+=sprintf(c+l,"No.\tPid\tCMD\n%d\t%d\t%s\n",count,p->pid,p->comm);
            l=l+length;
        }
        else{
            length=sprintf(c+l,"%d\t%d\t%s\n",count,p->pid,p->comm);
            l=l+length;
        }
    }
    printk(KERN_INFO "Total number of processes is: %d\n",count);
    length=sprintf(c+l,"Total number of processes is %d\n",count);
    l=l+length;

    //link proc file
    ricky_file->data=c;
    ricky_file->read_proc=proc_read_info;
    ricky_file->owner=THIS_MODULE;

    printk(KERN_INFO "%s %s initialized.\n", MODULE_NAME, MODULE_VERSION);
    return 0;

    no_rickyps:
        remove_proc_entry("rickyps",ricky_dir);
    out:
        return rv;
}

static void __exit ricky_info_exit(void)
{
    remove_proc_entry("rickyps",ricky_dir);
    remove_proc_entry(MODULE_NAME,NULL);
    printk(KERN_INFO "%s %s has been removed.\n",MODULE_NAME,MODULE_VERSION);
}

MODULE_AUTHOR("Ricky Song");
MODULE_LICENSE("GPL");

module_init(ricky_info_init);
module_exit(ricky_info_exit);

Makefile文件:
obj-m := ricky_proc.o
all:
make -C /lib/modules/$(shell uname -r)/build M=$(shell pwd) modules
clean:
rm -rf *.o *.mod.c *.ko Modules.symvers

内核模块创建在proc文件系统上建立_ps文件.遍例进程内核链表task_struct.将遍例结果存入缓冲区.影射到/proc/_ps文件中.用户态的程序去读取这个文件.打印显示当前进程的的pid,ppid 和进程名.

CODE:

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/sched.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("mq110");

static int ps_read(char *page, char **start, off_t offset,int count, int *eof, void *data)
{
static char buf[1024*8]={0};
char tmp[128];
struct task_struct *p;

if(offset >0)
      return 0;
memset(buf,0,sizeof(buf));
read_lock(&tasklist_lock);
for_each_process(p) //遍例内核进程链表.
{
      sprintf(tmp,"%d\t\t%d\t\t\t%s\n",p->pid,p->parent->pid,p->comm);
      strcat(buf,tmp);
      memset(tmp,0,sizeof(tmp));
}
read_unlock(&tasklist_lock);
*start=buf;
return strlen(buf);
}

static __init int ps_init(void)
{
struct proc_dir_entry *entry;

entry = create_proc_entry("_ps", 0444, &proc_root);  //建立/proc/_ps文件.
if(entry == 0)
{
      printk(KERN_ERR "create_proc_entry failed!\n");
      return -1;
}
entry->mode = S_IFREG | 0444;
entry->size = 0;
entry->read_proc = ps_read;
return 0;
}
static __exit void ps_cleanup(void)
{
remove_proc_entry("_ps", &proc_root);
}

module_init(ps_init);
module_exit(ps_cleanup);

以下是Makefile. TARGET改名成程序名就OK了.

CODE:

TARGET = 006
obj-m := $(TARGET).o
KERNELDIR=/lib/modules/`uname -r`/build
PWD=`pwd`

default :
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

install :
insmod $(TARGET).ko
uninstall :
rmmod $(TARGET).ko

clean :
rm -rf *.o *.mod.c *.ko

以下是用户态程序:

CODE:

#include <stdio.h>
#include <error.h>

int main()
{
FILE *fp;
char buf[1024];

fp=fopen("/proc/_ps","r");
if(fp==NULL)
{
      perror("fopen");
      return -1;
}
printf("pid\t\tppid\t\t\tcommand\n");
while(!feof(fp))
{
      if(fgets(buf,sizeof(buf),fp)!=NULL)
         printf("%s",buf);
}
fclose(fp);
return 0;
}

make ;make install 之后编译用户态程序.
执行结果:
[root@Firewall 006]# ./likeps
pid          ppid                   command
1             0                      init
2             1                      migration/0
3             1                      ksoftirqd/0
4             1                      watchdog/0
5             1                      migration/1
6             1                      ksoftirqd/1
7             1                      watchdog/1
8             1                      migration/2
9             1                      ksoftirqd/2
10             1                      watchdog/2
11             1                      migration/3
12             1                      ksoftirqd/3
13             1                      watchdog/3
14             1                      events/0
15             1                      events/1
16             1                      events/2
17             1                      events/3
18             1                      khelper
19             1                      kthread
24             19                   kacpid
100          19                   kblockd/0
101          19                   kblockd/1
102          19                   kblockd/2
103          19                   kblockd/3
106          19                   khubd
197          19                   pdflush
198          19                   pdflush
199          1                      kswapd0
200          19                   aio/0
201          19                   aio/1
202          19                   aio/2
203          19                   aio/3
288          19                   kseriod
392          1                      kjournald
1224          1                      udevd
1941          1                      kjournald
1944          1                      kjournald
1967          1                      kjournald
2820          1                      syslogd
2824          1                      klogd
2840          1                      sshd
2852          1                      vsftpd
2862          1                      gpm
2882          1                      atd
3184          1                      mingetty
3185          1                      mingetty
3186          1                      mingetty
3187          1                      mingetty
3188          1                      mingetty
3189          1                      mingetty
6819          1                      mysqld_safe
6846          6819                   mysqld
7475          1                      smbd
7476          7475                   smbd
7480          1                      nmbd
19400          2840                   sshd
19404          19400                bash

－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

让我们先来看看一个重要的结构体吧...struct task_struct 自己用sourceinsight看下在linux\sched.h里... pid parent->pid comm就是我们要的pid ppid cmd

注意当你添加了linux\sched.h后就有个current给你使用了,也是struct task_struct的...可以打印自身的pid cmd等

pid.c

#include <linux/kernel.h> #include <linux/module.h> #include <linux/proc_fs.h> #include <linux/init.h> #include <linux/sched.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("kenthy@163.com"); static int ps_read(char *page, char **start, off_t offset,int count, int*eof, void *data) { static char buf[1024*8]={0}; char tmp[128]; struct task_struct *p; if(offset >0) return 0; memset(buf,0,sizeof(buf)); read_lock(&tasklist_lock); for_each_process(p) { sprintf(tmp,"%d\t\t%d\t\t\t%s\n",p->pid,p->parent->pid,p->comm); strcat(buf,tmp); memset(tmp,0,sizeof(tmp)); } read_unlock(&tasklist_lock); *start=buf; return strlen(buf); } static __init int ps_init(void) { struct proc_dir_entry *entry; entry = create_proc_entry("_ps", 0444, &proc_root); if(entry == 0) { printk(KERN_ERR "create_proc_entry failed!\n"); return -1; } entry->mode = S_IFREG | 0444; entry->size = 0; entry->read_proc = ps_read; printk("%d, %d, %s\n", current->pid, current->parent->pid, current->comm); return 0; } static __exit void ps_cleanup(void) { remove_proc_entry("_ps", &proc_root); } module_init(ps_init); module_exit(ps_cleanup);

user.c

#include <stdio.h> #include <error.h> int main() { FILE *fp; char buf[1024]; fp=fopen("/proc/_ps","r"); if(fp==NULL) { perror("fopen"); return -1; } printf("pid\t\tppid\t\t\tcommand\n"); while(!feof(fp)) { if(fgets(buf,sizeof(buf),fp)!=NULL) printf("%s",buf); } fclose(fp); return 0; }

Makefile:

obj-m := pid.o KDIR := /lib/modules/$(shell uname -r)/build/ PWD := $(shell pwd) all:module module: $(MAKE) -C $(KDIR) M=$(PWD) modules clean: rm -rf *.ko *.mod.c *.o Module.* modules.* .*.cmd .tmp_versions

可以对ps_read做如下改进

static int ps_read(char *page, char **start, off_t off,int count, int*eof, void *data) { int len = 0; struct task_struct *p; read_lock(&tasklist_lock); for_each_process(p) len += sprintf(page+len,"%d\t\t%d\t\t\t%s\n",p->pid,p->parent->pid,p->comm); read_unlock(&tasklist_lock); if (len <= off+count) *eof = 1; *start = page + off; len -= off; if (len>count) len = count; if (len<0) len = 0; return len; }

for_each_process(p)遍历每一个进程

还可以用seq写个

#include <linux/init.h> #include <linux/module.h> #include <linux/proc_fs.h> //proc_fs #include <linux/seq_file.h> //seq_file #include <linux/fs.h> //struct file,struct inode #include <linux/sched.h> //next_task() MODULE_AUTHOR("xunil@bmy"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("a test module utilise the seq_file mechanism"); static void *ps_seq_start(struct seq_file *s,loff_t *pos){ struct task_struct *task; seq_printf(s,"%s\t%s\t%s\t%s\t%s\n","pid","ppid","uid","gid","comm"); if(*pos>0) return NULL; else{ task=next_task(current); return task; } } static void *ps_seq_next(struct seq_file *s,void *v,loff_t *pos){ struct task_struct *task=(struct task_struct *)v; ++*pos; if(task->pid== current->pid){ return NULL; }else{ task=next_task(task); return task; } } static void ps_seq_stop(struct seq_file *s,void *v){} static int ps_seq_show(struct seq_file *s,void *v){ rwlock_t lock = RW_LOCK_UNLOCKED; struct task_struct *task=(struct task_struct *)v; read_lock(&lock); seq_printf(s,"%d\t%d\t%d\t%d\t%s\n",task->pid,task->parent->pid,task->uid,task->gid,task->comm); read_unlock(&lock); return 0; } static struct seq_operations ps_seq_ops = { .start = ps_seq_start, .next = ps_seq_next, .stop = ps_seq_stop, .show = ps_seq_show }; static int ps_open(struct inode *inode,struct file *file){ return seq_open(file,&ps_seq_ops); } static struct file_operations ps_file_ops = { .owner = THIS_MODULE, .open = ps_open, .read = seq_read, .llseek = seq_lseek, .release= seq_release }; static int __init ps_init(void){ struct proc_dir_entry *entry; entry = create_proc_entry("myps",0,NULL); if(entry) entry->proc_fops = &ps_file_ops; return 0; } static void __exit ps_exit(void){ remove_proc_entry("myps",NULL); } module_init(ps_init); module_exit(ps_exit);

转 Linux内核 Ps模块,布布扣,bubuko.com

转 Linux内核 Ps模块

原文：http://www.cnblogs.com/i0ject/p/3656460.html

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