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/* utmp2.c for Linux, by poe@daimi.aau.dk */
/* This code is freely distributable and is covered by the GNU copyleft */
/* This implementation of the utmp and wtmp routines, is supposed to
conform to the XPG2 and SVID2 standards */
#include "utmp.h"
#include "utmp-wrap.h"
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
static char Utname[1024] = _PATH_UTMP;
static int Fd = -1;
static struct old_utmp Ut;
/* kludge for the benefit of getutent() whose semantics differs from the
other get..() functions. When set, getutent() will not read the
next entry in utmp, but immediatly returns &Ut, and resets the
flag. */
static int _getutent_flag = 0;
static int _old_setutent(void);
void old_setutent(void);
void old_utmpname(const char *name);
struct old_utmp *old_getutent(void);
struct old_utmp *old_getutid(struct old_utmp *ut);
struct old_utmp *old_getutline(struct old_utmp *ut);
static struct old_utmp *_pututline(struct old_utmp *ut);
void old_pututline(struct old_utmp *ut);
void old_endutent(void);
static int _old_setutent(void)
{
if(Fd != -1) close(Fd);
/* first try to get write permission, if that fails then
make do with read access */
if((Fd = open(Utname, O_RDWR)) < 0) {
if((Fd = open(Utname, O_RDONLY)) < 0) {
perror("_setutent: Can't open utmp file");
Fd = -1;
return 0;
}
}
if(read(Fd, (char *)&Ut, sizeof(Ut)) != sizeof(Ut)) {
Ut.ut_id[0]='\0';
return 0;
}
return 1;
}
void old_setutent(void)
{
(void)_old_setutent();
_getutent_flag = 1;
}
void old_utmpname(const char *name)
{
(void)strncpy(Utname, name, sizeof(Utname)-1);
if(Fd != -1) close(Fd);
Fd = -1;
}
/* always get the logical *next* entry from the utmp file */
struct old_utmp *old_getutent(void)
{
if(Fd == -1) {
if(!_old_setutent())
return (struct old_utmp *)0;
else {
_getutent_flag = 0;
return &Ut;
}
}
if(_getutent_flag) {
/* well, setutent() really got it for us */
_getutent_flag = 0;
return &Ut;
}
if(read(Fd, (char *)&Ut, sizeof(Ut)) != sizeof(Ut))
return (struct old_utmp *)0;
else
return &Ut;
}
struct old_utmp *old_getutid(struct old_utmp *ut)
{
if(Fd == -1)
if(!_old_setutent()) return (struct old_utmp *)0;
do {
if(RUN_LVL <= ut->ut_type && ut->ut_type <= OLD_TIME &&
Ut.ut_type == ut->ut_type) return &Ut;
if(INIT_PROCESS <= ut->ut_type && ut->ut_type <= DEAD_PROCESS &&
!strncmp(Ut.ut_id, ut->ut_id, sizeof(Ut.ut_id)))
return &Ut;
} while(read(Fd, (char *)&Ut, sizeof(Ut)) == sizeof(Ut));
return (struct old_utmp *)0;
}
struct old_utmp *old_getutline(struct old_utmp *ut)
{
if(Fd == -1)
if(!_old_setutent()) return (struct old_utmp *)0;
do {
if((Ut.ut_type == USER_PROCESS || Ut.ut_type == LOGIN_PROCESS)
&& !strncmp(Ut.ut_line, ut->ut_line, sizeof(Ut.ut_line)))
return &Ut;
} while(read(Fd, (char *)&Ut, sizeof(Ut)) == sizeof(Ut));
return (struct old_utmp *)0;
}
struct old_utmp *_pututline(struct old_utmp *ut)
{
struct old_utmp my_ut;
/* don't stomp on the new value even if it's in Ut */
if(ut == &Ut) {
(void)memcpy(&my_ut, &Ut, sizeof(Ut));
ut = &my_ut;
}
/* we don't check Fd here, getutid() does it for us; this way
we can create an utmp file from an empty file, if it should
get lost. */
if(old_getutid(ut)) {
(void)lseek(Fd, (off_t)-sizeof(Ut), SEEK_CUR);
if(write(Fd, (char *)ut, sizeof(Ut)) != sizeof(Ut))
return (struct old_utmp *)0;
} else {
(void)lseek(Fd, (off_t)0, SEEK_END);
if(write(Fd, (char *)ut, sizeof(Ut)) != sizeof(Ut))
return (struct old_utmp *)0;
}
/* if we get this far, we are successful */
if(ut == &my_ut)
(void)memcpy(&Ut, &my_ut, sizeof(Ut));
return &Ut;
}
void old_pututline(struct old_utmp *ut)
{
/* (void)_pututline(ut); */
if (_pututline(ut)==NULL) fprintf(stderr,"FEHLER\n");
}
void old_endutent(void)
{
if(Fd != -1) close(Fd);
Fd = -1;
}
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