misc.c

/*

   Copyright (C) 1996  Stephen Fegan

   This program is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free Software
   Foundation; either version 2 of the License, or (at your option) any later
   version.
   
   This program is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
   details.
   
   You should have received a copy of the GNU General Public License along with
   this program; if not, write to the Free Software Foundation, Inc., 675 Mass
   Ave, Cambridge, MA 02139, USA.
   
   please send patches or advice to: `flash@netsoc.ucd.ie'
   */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>

#include "exec.h"
#include "config.h"

extern time_t start_time;
extern char *progname;

extern char **environ;

/* Print an error message (str) on stderr, print any applicable system error,
 * wait for 1 sec (NCSA telnet) and exit */

void error (char *str)
{
  fprintf (stderr,"Error: %s\n", str);
  if(errno)fprintf(stderr,"%s\n",strerror(errno));
  sleep(1);
  exit (1);
}

/*
 * xmalloc()
 *
 * Input - size - number of bytes to allocate.
 * Returns - pointer to allocated space.
 *
 * This is a simple wrapper for malloc, so that we don't
 * need to worry about the return value of malloc being NULL
 */

void *xmalloc (size_t size)
{
  void *retval;
  
  if ((retval = malloc (size)) == NULL)
    error ("Out Of Memory");
  
  return (retval);
}

void *xrealloc (void *ptr, size_t size)
{
  void *retval;

  if((retval = realloc (ptr,size)) == NULL)
    error("Out of Memory");

  return (retval);
}

/*
 * check_type: describes the actions we take
 *  
 *      =0   : Full check. We pretend that we have seen new mail if
 *             there is some there before flash starts. Returns: 
 *             -1 error, 0 no new mail, 1 mail there (unread), 2 new mail.
 *
 *      =1   : Just peek to see if the mail status has changed.
 *             1 it has, 0 it has not;
 */

int mail_check(int check_type)
{
  static time_t mail_notify_time=0;
  static int was_there_mail_last_time=0;
#ifdef MAILDIR /* mailbox is in MAILDIR format */
  struct stat cur_file_stat,new_file_stat;
  int namelen=20;
  char cur_name[namelen+1],new_name[namelen+1];
#else /* mailbox or other */
  struct stat mail_file_stat;
#endif /* MAILDIR */
  time_t at,mt;
  char *mail_file_name;
  int retval;
  
  mail_file_name=getenv("MAIL");
  if(mail_file_name==NULL)
    {
      was_there_mail_last_time=0;
      return (check_type!=0)?0:-1;
    }

#ifdef MAILDIR 
  /* assumes 'mail_file_name' is Maildir/ */
  snprintf(cur_name,namelen,"%s%s",mail_file_name,"cur/");
  snprintf(new_name,namelen,"%s%s",mail_file_name,"new/");

  if(stat(cur_name,&cur_file_stat)<0)
    {
      was_there_mail_last_time=0;
      return (check_type!=0)?0:-1;
    }

  if(stat(new_name,&new_file_stat)<0)
    {
      was_there_mail_last_time=0;
      return (check_type!=0)?0:-1;
    }

  at=cur_file_stat.st_mtime;
  mt=new_file_stat.st_mtime;
#else

  if(stat(mail_file_name,&mail_file_stat)<0)
    {
      was_there_mail_last_time=0;
      return (check_type!=0)?0:-1;
    }

  at=mail_file_stat.st_atime;
  mt=mail_file_stat.st_mtime;
#endif

  /*
   * Return the nomail status (retval=0) if the mail has been read (atime)
   * since it was last written (mtime) OR if flash has been started since
   * it was written to ie. no notification is sent on login.
   *
   * Otherwise return mail present status (retval=1 or 2). Return 2 if
   * there was no mail the last time we checked; this status might invoke
   * a beep or something while retval=1 should only make the system keep
   * displaying mail notification.
   */

  if((at>=mt)||(mt<start_time))retval=0;
  else
    {
      if((mt>mail_notify_time)&&(was_there_mail_last_time==0))retval=2;
      else retval=1;

      if(check_type==0)time(&mail_notify_time);
    }

  if(check_type!=0)
    retval=((retval>0)!=was_there_mail_last_time);
  else
    was_there_mail_last_time=(retval>0);
  
  return retval;
}

int tty_cbreak(int fd, struct termios *saved)
{
  struct termios buf;

  if(tcgetattr(fd,saved)<0)
    return(-1);

  buf=*saved;

  buf.c_lflag &= ~(ICANON | ECHO);
  buf.c_cc[VMIN] = 1;
  buf.c_cc[VTIME] = 0;

  if(tcsetattr(fd,TCSAFLUSH,&buf)<0)
    return(-1);

  return(0);
}

int tty_reset(int fd, struct termios *saved)
{
  if(tcsetattr(fd,TCSAFLUSH,saved)<0)
    return(-1);

  return(0);
}

void pressanykey(void)
{
  struct termios saved;
  char cc;
  int olderrno,n;

  fprintf (stderr,"[----Hit the ENTER key when you're ready----] ");
  tcflush(0,TCIFLUSH);
  tty_cbreak(0,&saved);
  do
    {
      olderrno=errno;
      do
	{
	  errno=0;
	  n=read(0,&cc,1);
	  if(n==0)exit(0);
	  if(errno==EIO)GRAB_BACK_TTY;
	}while(errno==EIO&&errno!=ENOTTY);
    }while(cc!='\n');
  tcflush(0,TCIFLUSH);
  tty_reset(0,&saved);

  return;
}

static int copied=0;
static int emalloc=0;

static void copyenv(void)
{
  char **x,**y;
  int n;

  for(x=environ,n=0;*x!=NULL;x++)n++;
  n++;
  x=environ;

  emalloc=n+10;
  y=environ=xmalloc(emalloc*sizeof(*environ));

  while(*x!=NULL)
    {
      int n=strlen(*x)+1;
      *y=xmalloc(n);
      memcpy(*y,*x,n);
      x++,y++;
    }
  *y=NULL;

  copied=1;
  return;
}

int setenv(const char *name, const char *value, int overwrite)
{
  char **x;
  int n,nlen;

  if(!copied)copyenv();

  if(strchr(name,'=')!=NULL)
    {
      fprintf(stderr,"%s: setenv: Illegal variable name %s",progname,name);
      return -1;
    }

  nlen=strlen(name);

  x=environ;
  n=0;
  while((*x!=NULL)&&((memcmp(*x,name,nlen)!=0)||(*(*x+nlen)!='=')))x++,n++;
  n++;

  if(*x==NULL)
    {
#ifdef DEBUG
      fprintf(stderr,"setenv: Setting NEW variable %s\n",name);
#endif
      if(emalloc<n)
	{
	  emalloc=n+10; 
	  x=environ=xrealloc(environ,emalloc*sizeof(*environ)); 
	  while(*x!=NULL)x++;
	}
      *x=xmalloc(nlen+strlen(value)+2);
      strcpy(*x,name);
      *(*x+nlen)='=';
      strcpy(*x+nlen+1,value);
      *(++x)=NULL;
    }
  else if(overwrite)
    {
      int vlen=strlen(value);
#ifdef DEBUG
      fprintf(stderr,"setenv: Resetting variable %s\n",name);
#endif
      free(*x);
      *x=xmalloc(nlen+vlen+2);
      strcpy(*x,name);
      *(*x+nlen)='=';
      strcpy(*x+nlen+1,value);
    }
#ifdef DEBUG
  else fprintf(stderr,"setenv: NOT setting variable %s\n",name);
#endif
  
  return 1;
}

void unsetenv(const char *name)
{
  char **x,**y;
  int nlen;

  if(!copied)copyenv();
  
  if(strchr(name,'=')!=NULL)
    {
      fprintf(stderr,"%s: unsetenv: Illegal variable name %s",progname,name);
      return;
    }


  nlen=strlen(name);

  x=environ;
  while((*x!=NULL)&&((memcmp(*x,name,nlen)!=0)||(*(*x+nlen)!='=')))x++;
  if(*x!=NULL)
    {
#ifdef DEBUG
      fprintf(stderr,"unsetenv: Removing variable %s\n",name);
#endif
      free(*x);
      y=x;
      x++;
      while(*y!=NULL)*(y++)=*(x++);
    }
#ifdef DEBUG
  else fprintf(stderr,"unsetenv: Could not find variable %s\n",name);
#endif

  return;
}