Re: task_struct and uid of a task

[sena]

Hi Robin,

I have applied this to my local testing code and indendation is looking 
perfectly good.

indent -kr -i8 -psl -npcs -cp9 loadavg.c

Robin Thanks a lot for that.

Sena Seneviratne
Computer engineering Lab
Sydney University
Sydney



Robin Holt wrote:

> On Wed, Dec 31, 2003 at 07:06:52AM +1100, sena wrote:
>
> Sena,
>
> Why don't you pester me about this instead of bothering Rusty.
>
> What are you trying to accomplish?  Please be specific about what
> you are trying to find out and not how you are trying to do it.
>
> Another thing, I would _GREATLY_ appreciate code which has
> decent variable names and good indentation.  Assuming you are
> writing this on a Linux box with a standard development install,
> you should be able to do:
>
> indent -kr -i8 -psl -npcs -cp9 myfile.c
>
> and get very kernel-style code.  Won't fix the variable names, but
> at least braces will be indented.
>
> Thanks,
> Robin Holt
>
>  
>
> > Dear Rusty,
> >
> > Thank you for your previous reply. I feel like you would be able to 
> > assist me.
> >
> > Say a computer has 5 user logins name1(500), name2(501), 
> > name3(502).........name5(504) apart from root. If these 5 people 
> > remotely login and runs there jobs, then the user name of those jobs are 
> > name1,name2 and name3.
> >
> > Say if they use telnet to remotely login then those Tasks will be 
> > started under telnet server as children.
> >
> > As the children inherits uid, euid etc of the parents. That means telnet 
> > is run as root and it inherits uid<500.
> >
> > task_struct has uid and it is updated accordingly.
> >
> >
> > I have built the kernel 2.4.19sena1 successfully but this is my problem. 
> > The problem because child process inherits uid etc if I start any 
> > process through telnet
> >
> > My code is as follows:
> >
> > unsigned long a; //for root uid<500, I am getting this uidArray[0] is 
> > for storing uid (assumed 100 for all <500)
> > unsigned long b; //for 500
> > unsigned long c; //for 501
> > unsigned long d; //for 502
> > unsigned long e; //for 503
> > unsigned long f; // for 504
> >
> > unsigned int uidArray[7];
> >
> > static unsigned long count_active_tasks(void)
> > {
> >   struct task_struct *p;
> >   unsigned long nr = 0;
> >
> >   int s = 0;
> >  
> >   int i=0;
> >   int j=0;
> >   int k=0;
> >   int m=0;
> >
> >   a=b=c=d=e=f=0;
> >  
> >      read_lock(&tasklist_lock);
> >
> >   for_each_task(p)
> >   {
> >       if ((p->state == TASK_RUNNING ||
> >            (p->state & TASK_UNINTERRUPTIBLE)))
> >   {
> >
> >       nr += FIXED_1; //nr total tasks
> >      
> >       if(i==0)
> >       {
> >           uidArray[0] = 100;
> >
> >           if(p->uid < 500)
> >           {
> >          
> >           a += FIXED_1;
> >           }
> >           else
> >           {
> >           uidArray[1] = p->uid;
> >           b += FIXED_1;
> >           k++;
> >           }
> >        k++;
> >       }
> >       else
> >       {
> >          for(j=0; j < k ; j++)
> >          {
> >              
> >           if((j==0)&& (p->uid < 500) && (s==0))
> >           {
> >               a += FIXED_1;
> >               s = 1;
> >               break;
> >           }
> >           else if((uidArray[j] == p->uid) && s==0)
> >           {
> >               if(j==1){
> >               b += FIXED_1;}
> >               if(j==2){
> >               c += FIXED_1;}
> >               if(j==3){
> >               d += FIXED_1;}
> >               if(j==4){
> >               e += FIXED_1;}
> >               if(j==5){
> >               f += FIXED_1;}
> >               s=1;
> >               break;
> >           }
> >           }
> >  
> >           if(s==0)
> >           {
> >
> >           if(k < 6)
> >              {
> >               k++;
> >               j = k-1;
> >               uidArray[j] = p->uid;
> >               if(j==1){
> >               b += FIXED_1;}
> >               if(j==2){
> >               c += FIXED_1;}
> >               if(j==3){
> >               d += FIXED_1;}
> >               if(j==4){
> >               e += FIXED_1;}
> >               if(j==5){
> >               f += FIXED_1;}
> >              }
> >              
> >
> >           }
> >
> >       s=0;
> >         }
> >      
> >       i++;
> >  
> >   }
> >
> >   }
> >          
> >   read_unlock(&tasklist_lock);
> >   return nr;
> >
> > }
> >
> > unsigned long avenrun[6];
> >
> > unsigned long avenrunT;
> >
> > static inline void calc_load(unsigned long ticks)
> > {
> >   unsigned long active_tasks;  /*fixed-point */
> >   static int count = LOAD_FREQ;
> >
> >   count -= ticks;
> >   if (count < 0) {
> >       count += LOAD_FREQ;
> >       active_tasks = count_active_tasks();
> >
> >       CALC_LOAD(avenrunT, EXP_5, active_tasks);
> >       CALC_LOAD(avenrun[0], EXP_5, a);
> >       CALC_LOAD(avenrun[1], EXP_5, b);
> >       CALC_LOAD(avenrun[2], EXP_5, c);
> >       CALC_LOAD(avenrun[3], EXP_5, d);
> >       CALC_LOAD(avenrun[4], EXP_5, e);
> >       CALC_LOAD(avenrun[5], EXP_5, f);
> >      
> >   }
> > }
> >
> > I have updated all the other places(all .h and .c files) to suit this code.
> >
> > And the result is stored in    proc/loadavg as
> >
> >       0.21   0.21   100   0.00     0       0.00      0        0.00     
> > 0        0.00     0            0.00        0
> >         T        a 1      uid     b1    500        c 1     501      d1 
> >    502      e1      503          f1         504
> >
> > T- for totall
> > a1- root or uid < 500
> > b1,c1,di etc for uid>=500
> >
> > In this perticular case I have login as root so that uid 100 is seen. 
> > There is no 500 or above. they are all 0.
> >
> > But even if I start login remotely those processors started through 
> > telnet inherits uid <500. Then they will be shown under a1
> >
> > I get uids from task_struct
> >
> > Thanks
> > Sena Seneviratne
> > Computer Engineering Lab
> > School of Electrical and Information Engineering
> > Sydney University
> >
> > -
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> >    
>
>  



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