Re: WTMP file

[Dan Yefimov <dan () D00M integrate com ru>]

On Wed, 5 Nov 2003, BORJA RUIZ CASTRO MORON wrote:

> Hi! I╢m coding an aplication for remove user entries in WTMP.
> I think the code is OK,but it does not work! :P
> Could somebody take a look please? 
>
> Thanks a lot! :D 
>
>
>  ----------------------------------------------
> #include <stdio.h>
> #include <fcntl.h>
> #include <pwd.h>
> #include <unistd.h>
> #include <utmp.h>
> #include <sys/time.h> 
>
> #define WTMP "/var/log/wtmp" 
>
> int main (int argc, char **argv){ 
>
> int fd; 
>
> struct passwd *acceso;
> struct utmp rosita;
> setutent(); 
>
> if (argc<2) {
>  printf("Usage: %s <user>\n",argv[0]);
>  exit(-1);
>  }
> if((fd=open(WTMP,O_WRONLY))<0) {
>  printf("\nFile not found.\n\n");
>  exit(-1);
>  } 
>
> if ((acceso=getpwnam(argv[1]))==NULL) {
>  printf("\nUnknow user :P\n\n");
>  exit(-1);
>  } 
>
> // Our info 
>
> rosita.ut_type=DEAD_PROCESS;
> memset(rosita.ut_line,0,UT_LINESIZE);
> memset(rosita.ut_user,0,UT_NAMESIZE);
> memset(rosita.ut_host,0,UT_HOSTSIZE);
> rosita.ut_time=0; 
>
> while((acceso=getpwent())!=NULL) { 
>
> lseek(fd,sizeof(struct utmp)*acceso->pw_uid,SEEK_SET);
> pututline(&rosita);
> } 
>
> endutent(); 
>
> close(fd);
> return(0);
> } 
It won't work because utmp/wtmp files aren't ordered by uid. For this program to 
work you should scan utmp file for records related to the given uid.
-- 

    Sincerely Your, Dan.