#include <utmpx.h>
#include <stddef.h>
#include "libc.h"

#define _PATH_UTMPX "/etc/utmp"

static FILE *f;
static struct utmpx ut;

void endutxent(void)
{
  if (f == NULL) return;
  fclose(f);
  f == NULL;
}

void setutxent(void)
{
  if (f == NULL) return;
  rewind(f);
}

struct utmpx *getutxent(void)
{
  if (f == NULL) {
    f = fopen(_PATH_UTMPX, "r+");
    if (f == NULL) {
      f = fopen(_PATH_UTMPX, "r");
      if (f == NULL) return NULL;
    }
  }
  if (fread(&ut, sizeof ut, 1, f)) return &ut;
  return NULL;
}

struct utmpx *getutxid(const struct utmpx *id)
{  
  while(getutxent()) {
    switch (id->ut_type) {
      case BOOT_TIME:
      case OLD_TIME:
      case NEW_TIME:
        if (id->ut_type == ut.ut_type) return &ut;
        break;
      case INIT_PROCESS:
      case LOGIN_PROCESS:
      case USER_PROCESS:
      case DEAD_PROCESS:
        if (id->type == ut.ut_type && !strncmp(id->ut_id, ut.ut_id, sizeof ut.ut_id)) return &ut;
        break;
    }
  }    
  return NULL;
}

struct utmpx *getutxline(const struct utmpx *line)
{
	while(getutxent()) {
    switch (ut.ut_type) {
      case LOGIN_PROCESS:
      case USER_PROCESS:
        if (!strncmp(line->ut_line, ut.ut_line, sizeof ut.ut_line)) return &ut;
        break;
    }
  }
  return NULL;
}

struct utmpx *pututxline(const struct utmpx *utmpx)
{
  struct flock fl;
  size_t n;
  
  fl.l_start = 0;
  fl.l_len = 0;
  fl.l_pid = getpid();
  fl.l_type = F_WRLCK;
  fl.l_whence = SEEK_SET;
  
  if (fcntl(fileno(f), F_SETLKW, &fl) < 0) return NULL;
  
  setutxent();
  
  if (getutxid(utmpx)) fseek(f, -((long)(sizeof ut)), SEEK_CUR);
  
  n = fwrite(&ut, sizeof ut, 1, f);
  
  fl.l_type = F_UNLCK;
  fcntl(fileno(f), F_SETLK, &fl);
  
  if (n == 1)
    return &ut;
  return NULL;
}

void updwtmpx(const char *f, const struct utmpx *u)
{
}

weak_alias(endutxent, endutent);
weak_alias(setutxent, setutent);
weak_alias(getutxent, getutent);
weak_alias(getutxid, getutid);
weak_alias(getutxline, getutline);
weak_alias(pututxline, pututline);
weak_alias(updwtmpx, updwtmp);