/*
 * Program:	Operating-system dependent routines -- 4.3BSD version
 *
 * Author:	Mark Crispin
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: MRC@CAC.Washington.EDU
 *
 * Date:	1 August 1988
 * Last Edited:	14 May 1992
 *
 * Copyright 1992 by the University of Washington
 *
 *  Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notice appears in all copies and that both the
 * above copyright notice and this permission notice appear in supporting
 * documentation, and that the name of the University of Washington not be
 * used in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  This software is made
 * available "as is", and
 * THE UNIVERSITY OF WASHINGTON DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
 * WITH REGARD TO THIS SOFTWARE, INCLUDING WITHOUT LIMITATION ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, AND IN
 * NO EVENT SHALL THE UNIVERSITY OF WASHINGTON BE LIABLE FOR ANY SPECIAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, TORT
 * (INCLUDING NEGLIGENCE) OR STRICT LIABILITY, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */


#define isodigit(c)    (((unsigned)(c)>=060)&((unsigned)(c)<=067))
#define toint(c)       ((c)-'0')


/* TCP input buffer */

#define BUFLEN 8192


/* TCP I/O stream (must be before osdep.h is included) */

#define TCPSTREAM struct tcp_stream
TCPSTREAM {
  char *host;			/* host name */
  char *localhost;		/* local host name */
  int tcpsi;			/* input socket */
  int tcpso;			/* output socket */
  int ictr;			/* input counter */
  char *iptr;			/* input pointer */
  char ibuf[BUFLEN];		/* input buffer */
};


#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <ctype.h>
#include <errno.h>
extern int errno;		/* just in case */
#include <pwd.h>
#include <syslog.h>
#include "osdep.h"
#include "mail.h"
#include "misc.h"

/* Write current time in RFC 822 format
 * Accepts: destination string
 */

char *days[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
char *months[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

void rfc822_date (date)
	char *date;
{
  int zone;
  char *zonename;
  struct tm *t;
  struct timeval tv;
  struct timezone tz;
  gettimeofday (&tv,&tz);	/* get time and timezone poop */
  t = localtime (&tv.tv_sec);	/* convert to individual items */
  zone = timezone/60;	/* get timezone from TZ environment stuff */
  zonename = daylight ? tzname[0] : tzname[1] ;
                                /* and output it */
  sprintf (date,"%s, %d %s %d %02d:%02d:%02d %+03d%02d (%s)",
	   days[t->tm_wday],t->tm_mday,months[t->tm_mon],t->tm_year+1900,
	   t->tm_hour,t->tm_min,t->tm_sec,zone/60,abs (zone) % 60,zonename);
}

/* Get a block of free storage
 * Accepts: size of desired block
 * Returns: free storage block
 */

void *fs_get (size)
	size_t size;
{
  void *block = malloc (size);
  if (!block) fatal ("Out of free storage");
  return (block);
}


/* Resize a block of free storage
 * Accepts: ** pointer to current block
 *	    new size
 */

void fs_resize (block,size)
	void **block;
	size_t size;
{
  if (!(*block = realloc (*block,size))) fatal ("Can't resize free storage");
}


/* Return a block of free storage
 * Accepts: ** pointer to free storage block
 */

void fs_give (block)
	void **block;
{
  free (*block);
  *block = NIL;
}


/* Report a fatal error
 * Accepts: string to output
 */

void fatal (string)
	char *string;
{
  mm_fatal (string);		/* output the string */
  syslog (LOG_ALERT,"IMAP C-Client crash: %s",string);
  abort ();			/* die horribly */
}

/* Copy string with CRLF newlines
 * Accepts: destination string
 *	    pointer to size of destination string
 *	    source string
 *	    length of source string
 */

char *strcrlfcpy (dst,dstl,src,srcl)
	char **dst;
	unsigned long *dstl;
	char *src;
	unsigned long srcl;
{
  long i,j;
  char *d = src;
				/* count number of LF's in source string(s) */
  for (i = srcl,j = 0; j < srcl; j++) if (*d++ == '\012') i++;
  if (i > *dstl) {		/* resize if not enough space */
    fs_give ((void **) dst);	/* fs_resize does an unnecessary copy */
    *dst = (char *) fs_get ((*dstl = i) + 1);
  }
  d = *dst;			/* destination string */
				/* copy strings, inserting CR's before LF's */
  while (srcl--) switch (*src) {
  case '\015':			/* unlikely carriage return */
    *d++ = *src++;		/* copy it and any succeeding linefeed */
    if (srcl && *src == '\012') {
      *d++ = *src++;
      srcl--;
    }
    break;
  case '\012':			/* line feed? */
    *d++ ='\015';		/* yes, prepend a CR, drop into default case */
  default:			/* ordinary chararacter */
    *d++ = *src++;		/* just copy character */
    break;
  }
  *d = '\0';			/* tie off destination */
  return *dst;			/* return destination */
}


/* Length of string after strcrlflen applied
 * Accepts: source string
 *	    length of source string
 */

unsigned long strcrlflen (src,srcl)
	char *src;
	unsigned long srcl;
{
  long i = srcl;		/* look for LF's */
  while (srcl--) switch (*src++) {
  case '\015':			/* unlikely carriage return */
    if (srcl && *src == '\012') { src++; srcl--; }
    break;
  case '\012':			/* line feed? */
    i++;
  default:			/* ordinary chararacter */
    break;
  }
  return i;
}

/* Server log in
 * Accepts: user name string
 *	    password string
 *	    optional place to return home directory
 * Returns: T if password validated, NIL otherwise
 */

long server_login (user,pass,home)
	char *user;
	char *pass;
	char **home;
{
  struct passwd *pw = getpwnam (lcase (user));
				/* no entry for this user or root */
  if (!(pw && pw->pw_uid)) return NIL;
				/* validate password */
  if (strcmp (pw->pw_passwd,(char *) crypt (pass,pw->pw_passwd))) return NIL;
  setgid (pw->pw_gid);		/* all OK, login in as that user */
  setuid (pw->pw_uid);
				/* note home directory */
  if (home) *home = cpystr (pw->pw_dir);
  return T;
}

/* TCP/IP open
 * Accepts: host name
 *	    contact port number
 * Returns: TCP/IP stream if success else NIL
 */

TCPSTREAM *tcp_open (host,port)
	char *host;
	long port;
{
  TCPSTREAM *stream = NIL;
  int sock;
  char *s;
  struct sockaddr_in sin;
  struct hostent *host_name;
  char hostname[MAILTMPLEN];
  char tmp[MAILTMPLEN];
  /* The domain literal form is used (rather than simply the dotted decimal
     as with other Unix programs) because it has to be a valid "host name"
     in mailsystem terminology. */
				/* look like domain literal? */
  if (host[0] == '[' && host[(strlen (host))-1] == ']') {
    strcpy (hostname,host+1);	/* yes, copy number part */
    hostname[(strlen (hostname))-1] = '\0';
    if ((sin.sin_addr.s_addr = inet_addr (hostname)) != -1) {
      sin.sin_family = AF_INET;	/* family is always Internet */
      strcpy (hostname,host);	/* hostname is user's argument */
    }
    else {
      sprintf (tmp,"Bad format domain-literal: %.80s",host);
      mm_log (tmp,ERROR);
      return NIL;
    }
  }

  else {			/* lookup host name, note that brain-dead Unix
				   requires lowercase! */
    strcpy (hostname,host);	/* in case host is in write-protected memory */
    if ((host_name = gethostbyname (lcase (hostname)))) {
				/* copy address type */
      sin.sin_family = host_name->h_addrtype;
				/* copy host name */
      strcpy (hostname,host_name->h_name);
				/* copy host addresses */
      memcpy (&sin.sin_addr,host_name->h_addr,host_name->h_length);
    }
    else {
      sprintf (tmp,"No such host as %.80s",host);
      mm_log (tmp,ERROR);
      return NIL;
    }
  }

				/* copy port number in network format */
  if (!(sin.sin_port = htons (port))) fatal ("Bad port argument to tcp_open");
				/* get a TCP stream */
  if ((sock = socket (sin.sin_family,SOCK_STREAM,0)) < 0) {
    sprintf (tmp,"Unable to create TCP socket: %s",strerror (errno));
    mm_log (tmp,ERROR);
    return NIL;
  }
				/* open connection */
  if (connect (sock,(struct sockaddr *)&sin,sizeof (sin)) < 0) {
    sprintf (tmp,"Can't connect to %.80s,%d: %s",hostname,port,
	     strerror (errno));
    mm_log (tmp,ERROR);
    return NIL;
  }
				/* create TCP/IP stream */
  stream = (TCPSTREAM *) fs_get (sizeof (TCPSTREAM));
				/* copy official host name */
  stream->host = cpystr (hostname);
				/* get local name */
  gethostname (tmp,MAILTMPLEN-1);
  stream->localhost = cpystr ((host_name = gethostbyname (tmp)) ?
			      host_name->h_name : tmp);
				/* init sockets */
  stream->tcpsi = stream->tcpso = sock;
  stream->ictr = 0;		/* init input counter */
  return stream;		/* return success */
}

/* TCP/IP authenticated open
 * Accepts: host name
 *	    service name
 * Returns: TCP/IP stream if success else NIL
 */

TCPSTREAM *tcp_aopen (host,service)
	char *host;
	char *service;
{
  TCPSTREAM *stream = NIL;
  struct hostent *host_name;
  char hostname[MAILTMPLEN];
  int i;
  int pipei[2],pipeo[2];
  /* The domain literal form is used (rather than simply the dotted decimal
     as with other Unix programs) because it has to be a valid "host name"
     in mailsystem terminology. */
				/* look like domain literal? */
  if (host[0] == '[' && host[i = (strlen (host))-1] == ']') {
    strcpy (hostname,host+1);	/* yes, copy without brackets */
    hostname[i-1] = '\0';
  }
				/* note that Unix requires lowercase! */
  else if (host_name = gethostbyname (lcase (strcpy (hostname,host))))
    strcpy (hostname,host_name->h_name);
				/* make command pipes */
  if (pipe (pipei) < 0) return NIL;
  if (pipe (pipeo) < 0) {
    close (pipei[0]); close (pipei[1]);
    return NIL;
  }
  if ((i = fork ()) < 0) {	/* make inferior process */
    close (pipei[0]); close (pipei[1]);
    close (pipeo[0]); close (pipeo[1]);
    return NIL;
  }
  if (i) {			/* parent? */
    close (pipei[1]);		/* close child's side of the pipes */
    close (pipeo[0]);
  }
  else {			/* child */
    dup2 (pipei[1],1);		/* parent's input is my output */
    dup2 (pipei[1],2);		/* parent's input is my error output too */
    close (pipei[0]); close (pipei[1]);
    dup2 (pipeo[0],0);		/* parent's output is my input */
    close (pipeo[0]); close (pipeo[1]);
				/* now run it */
    execl ("/usr/ucb/rsh","rsh",hostname,"exec",service,0);
    _exit (1);			/* spazzed */
  }

				/* create TCP/IP stream */
  stream = (TCPSTREAM *) fs_get (sizeof (TCPSTREAM));
				/* copy official host name */
  stream->host = cpystr (hostname);
				/* get local name */
  gethostname (hostname,MAILTMPLEN-1);
  stream->localhost = cpystr ((host_name = gethostbyname (hostname)) ?
			      host_name->h_name : hostname);
  stream->tcpsi = pipei[0];	/* init sockets */
  stream->tcpso = pipeo[1];
  stream->ictr = 0;		/* init input counter */
  return stream;		/* return success */
}

/* TCP/IP receive line
 * Accepts: TCP/IP stream
 * Returns: text line string or NIL if failure
 */

char *tcp_getline (stream)
	TCPSTREAM *stream;
{
  int n,m;
  char *st;
  char *ret;
  char *stp;
  char tmp[2];
  fd_set fds;
  FD_ZERO (&fds);		/* initialize selection vector */
  if (stream->tcpsi < 0) return NIL;
  while (stream->ictr < 1) {	/* if nothing in the buffer */
    FD_SET (stream->tcpsi,&fds);/* set bit in selection vector */
				/* block and read */
    if ((select (stream->tcpsi+1,&fds,0,0,0) < 0) ||
	((stream->ictr = read (stream->tcpsi,stream->ibuf,BUFLEN)) < 1)) {
      close (stream->tcpsi);	/* nuke the socket */
      if (stream->tcpsi != stream->tcpso) close (stream->tcpso);
      stream->tcpsi = stream->tcpso = -1;
      return NIL;
    }
    stream->iptr = stream->ibuf;/* point at TCP buffer */
  }
  st = stream->iptr;		/* save start of string */
  n = 0;			/* init string count */
  while (stream->ictr--) {	/* look for end of line */
				/* saw the trailing CR? */
    if (stream->iptr++[0] == '\015') {
      ret = (char *) fs_get (n+1);
      memcpy (ret,st,n);	/* copy into a free storage string */
      ret[n] = '\0';		/* tie off string with null */
				/* eat the line feed */
      tcp_getbuffer (stream,1,tmp);
      return ret;		/* return it to caller */
    }
    ++n;			/* else count and try next character */
  }
  stp = (char *) fs_get (n);	/* copy first part of string */
  memcpy (stp,st,n);
				/* recurse to get remainder */
  if (st = tcp_getline (stream)) {
				/* build total string */
    ret = (char *) fs_get (n+1+(m = strlen (st)));
    memcpy (ret,stp,n);		/* copy first part */
    memcpy (ret+n,st,m);	/* and second part */
    ret[n+m] = '\0';		/* tie off string with null */
    fs_give ((void **) &st);	/* flush partial string */
    fs_give ((void **) &stp);	/* flush initial fragment */
  }
  else ret = stp;		/* return the fragment */
  return ret;
}

/* TCP/IP receive buffer
 * Accepts: TCP/IP stream
 *	    size in bytes
 *	    buffer to read into
 * Returns: T if success, NIL otherwise
 */

long tcp_getbuffer (stream,size,buffer)
	TCPSTREAM *stream;
	unsigned long size;
	char *buffer;
{
  unsigned long n;
  char *bufptr = buffer;
  fd_set fds;
  FD_ZERO (&fds);		/* initialize selection vector */
  if (stream->tcpsi < 0) return NIL;
  while (size > 0) {		/* until request satisfied */
    while (stream->ictr < 1) {	/* if nothing in the buffer */
      FD_SET (stream->tcpsi,&fds);
				/* block and read */
      if ((select (stream->tcpsi+1,&fds,0,0,0) < 0) ||
	  ((stream->ictr = read (stream->tcpsi,stream->ibuf,BUFLEN)) < 1)) {
	close (stream->tcpsi);	/* nuke the socket */
	if (stream->tcpsi != stream->tcpso) close (stream->tcpso);
	stream->tcpsi = stream->tcpso = -1;
	return NIL;
      }
				/* point at TCP buffer */
      stream->iptr = stream->ibuf;
    }
    n = min (size,stream->ictr);/* number of bytes to transfer */
				/* do the copy */
    memcpy (bufptr,stream->iptr,n);
    bufptr += n;		/* update pointer */
    stream->iptr +=n;
    size -= n;			/* update # of bytes to do */
    stream->ictr -=n;
  }
  bufptr[0] = '\0';		/* tie off string */
  return T;
}

/* TCP/IP send string as record
 * Accepts: TCP/IP stream
 * Returns: T if success else NIL
 */

long tcp_soutr (stream,string)
	TCPSTREAM *stream;
	char *string;
{
  int i;
  unsigned long size = strlen (string);
  fd_set fds;
  FD_ZERO (&fds);		/* initialize selection vector */
  if (stream->tcpso < 0) return NIL;
  while (size > 0) {		/* until request satisfied */
    FD_SET (stream->tcpso,&fds);/* set bit in selection vector */
    if ((select (stream->tcpso+1,0,&fds,0,0) < 0) ||
	((i = write (stream->tcpso,string,size)) < 0)) {
      puts (strerror (errno));
      close (stream->tcpsi);	/* nuke the socket */
      if (stream->tcpsi != stream->tcpso) close (stream->tcpso);
      stream->tcpsi = stream->tcpso = -1;
      return NIL;
    }
    size -= i;			/* count this size */
    string += i;
  }
  return T;			/* all done */
}


/* TCP/IP close
 * Accepts: TCP/IP stream
 */

void tcp_close (stream)
	TCPSTREAM *stream;
{

  if (stream->tcpsi >= 0) {	/* no-op if no socket */
    close (stream->tcpsi);	/* nuke the socket */
    if (stream->tcpsi != stream->tcpso) close (stream->tcpso);
    stream->tcpsi = stream->tcpso = -1;
  }
				/* flush host names */
  fs_give ((void **) &stream->host);
  fs_give ((void **) &stream->localhost);
  fs_give ((void **) &stream);	/* flush the stream */
}

/* TCP/IP get host name
 * Accepts: TCP/IP stream
 * Returns: host name for this stream
 */

char *tcp_host (stream)
	TCPSTREAM *stream;
{
  return stream->host;		/* return host name */
}


/* TCP/IP get local host name
 * Accepts: TCP/IP stream
 * Returns: local host name
 */

char *tcp_localhost (stream)
	TCPSTREAM *stream;
{
  return stream->localhost;	/* return local host name */
}



/* Return pointer to first occurance in string of a substring
 * Accepts: source pointer
 *	    substring pointer
 * Returns: pointer to substring in source or NIL if not found
 */
#ifndef LINUX
char *strstr (cs,ct)
     char *cs;
     char *ct;
{
  char *s;
  char *t;
  while (cs = index (cs,*ct)) {	/* for each occurance of the first character */
				/* see if remainder of string matches */
    for (s = cs + 1, t = ct + 1; *t && *s == *t; s++, t++);
    if (!*t) return cs;		/* if ran out of substring then have match */
    cs++;			/* try from next character */
  }
  return NIL;			/* not found */
}
#endif /* LINUX */

/* Return implementation-defined string corresponding to error
 * Accepts: error number
 * Returns: string for that error
 */

char *strerror (n)
     int n;
{
  extern char *sys_errlist[];
  extern int sys_nerr;

  return (n >= 0 && n < sys_nerr) ? sys_errlist[n] : NIL;
}



/* Copy memory block
 * Accepts: destination pointer
 *	    source pointer
 *	    length
 * Returns: destination pointer
 */
#ifndef LINUX
char *memmove (s,ct,n)
     char *s;
     char *ct;
     int n;
{
  bcopy (ct,s,n);		/* they should have this one */
  return ct;
}
#endif /* LINUX */


/*
 * Turn a string long into the real thing
 * Accepts: source string
 *	    pointer to place to return end pointer
 *	    base
 * Returns: parsed long integer, end pointer is updated
 */

long strtol (s,endp,base)
     char *s;
     char **endp;
     int base;
{
  long value = 0;		/* the accumulated value */
  int negative = 0;		/* this a negative number? */
  int ok;			/* true while valid chars for number */
  char c;
				/* insist upon valid base */
  if (base && (base < 2 || base > 36)) return NIL;
  while (isspace (*s)) s++;	/* skip leading whitespace */
  if (!base) {			/* if base = 0, */
    if (*s == '-') {		/* integer constants are allowed a */
      negative = 1;		/* leading unary minus, but not */
      s++;			/* unary plus. */
    }
    else negative = 0;
    if (*s == '0') {		/* if it starts with 0, its either */
				/* 0X, which marks a hex constant, */
      if (toupper (*++s) == 'X') {
	s++;			/* skip the X */
       	base = 16;		/* base is hex 16 */
      }
      else base = 8;		/* leading 0 means octal number */
    }
    else base = 10;		/* otherwise, decimal. */
    do {
      switch (base) {		/* char has to be valid for base */
      case 8:			/* this digit ok? */
	ok = isodigit(*s);
	break;
      case 10:
	ok = isdigit(*s);
	break;
      case 16:
	ok = isxdigit(*s);
	break;
      default:			/* it's good form you know */
	return NIL;
      }
				/* if valid char, accumulate */
      if (ok) value = value * base + toint(*s++);
    } while (ok);
    if (toupper(*s) == 'L') s++;/* ignore 'l' or 'L' marker */
    if (endp) *endp = s;	/* set user pointer to after num */
    return (negative) ? -value : value;
  }

  switch (*s) {			/* check for leading sign char */
  case '-':
    negative = 1;		/* yes, negative #.  fall into '+' */
  case '+':
    s++;			/* skip the sign character */
  }
				/* allow hex prefix "0x" */
  if (base == 16 && *s == '0' && toupper (*(s + 1)) == 'X') s += 2;
  do {
				/* convert to numeric form if digit*/
    if (isdigit (*s)) c = toint (*s);
				/* alphabetic conversion */
    else if (isalpha (*s)) c = *s - (isupper (*s) ? 'A' : 'a') + 10;
    else break;			/* else no way it's valid */
    if (c >= base) break;	/* digit out of range for base? */
    value = value * base + c;	/* accumulate the digit */
  } while (*++s);		/* loop until non-numeric character */
  if (endp) *endp = s;		/* save users endp to after number */
				/* negate number if needed */
  return (negative) ? -value : value;
}
