/* sendmail-like interface to /bin/mail for system V,
   Copyright (C) 1985 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY.  No author or distributor
accepts responsibility to anyone for the consequences of using it
or for whether it serves any particular purpose or works at all,
unless he says so in writing.  Refer to the GNU Emacs General Public
License for full details.

Everyone is granted permission to copy, modify and redistribute
GNU Emacs, but only under the conditions described in the
GNU Emacs General Public License.   A copy of this license is
supposed to have been given to you along with GNU Emacs so you
can know your rights and responsibilities.  It should be in a
file named COPYING.  Among other things, the copyright notice
and this notice must be preserved on all copies.  */


#define NO_SHORTNAMES
#include "../src/config.h"

#if defined (BSD) && !defined (BSD4_1)
/* This program isnot used in BSD, so just avoid loader complaints.  */
main ()
{
}
#else /* not BSD 4.2 (or newer) */
/* This conditional contains all the rest of the file.  */

/* These are defined in config in some versions. */

#ifdef static
#undef static
#endif

#ifdef read
#undef read
#undef write
#undef open
#endif

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <pwd.h>

/* Type definitions */

#define boolean int
#define true 1
#define false 0

/* Various lists */

struct line_record
{
  char *string;
  struct line_record *continuation;
};
typedef struct line_record *line_list;

struct header_record
{
  line_list text;
  struct header_record *next;
  struct header_record *previous;
};
typedef struct header_record *header;
			
struct stream_record
{
  FILE *handle;
  int (*action)();
  struct stream_record *rest_streams;
};
typedef struct stream_record *stream_list;

/* A `struct linebuffer' is a structure which holds a line of text.
 * `readline' reads a line from a stream into a linebuffer
 * and works regardless of the length of the line.
 */

struct linebuffer
{
  long size;
  char *buffer;
};

struct linebuffer lb;

#define new_list()					\
  ((line_list) xmalloc (sizeof (struct line_record)))
#define new_header()				\
  ((header) xmalloc (sizeof (struct header_record)))
#define new_stream()				\
  ((stream_list) xmalloc (sizeof (struct stream_record)))
#define alloc_string(nchars)				\
  ((char *) xmalloc ((nchars) + 1))

/* Global declarations */

#define BUFLEN 1024
#define KEYWORD_SIZE 256
#define PROGRAM_NAME "/bin/mail"
#define FROM_PREFIX "From"
#define MY_NAME "fakemail"
#define NIL ((line_list) NULL)
#define INITIAL_LINE_SIZE 200

static char *my_name;
static char *the_date;
static char *the_user;
static line_list file_preface;
static stream_list the_streams;
static boolean no_problems = true;

extern FILE *popen ();
extern int fclose (), pclose ();
extern char *malloc (), *realloc ();

#ifdef CURRENT_USER
extern struct passwd *getpwuid ();
extern unsigned short geteuid ();
static struct passwd *my_entry;
#define cuserid(s)				\
(my_entry = getpwuid (((int) geteuid ())),	\
 my_entry->pw_name)
#endif

/* Utilities */

/* Print error message.  `s1' is printf control string, `s2' is arg for it. */

static void
error (s1, s2)
     char *s1, *s2;
{
  printf ("%s: ", my_name);
  printf (s1, s2);
  printf ("\n");
  no_problems = false;
}

/* Print error message and exit.  */

static void
fatal (s1, s2)
     char *s1, *s2;
{
  error (s1, s2);
  exit (1);
}

/* Like malloc but get fatal error if memory is exhausted.  */

static char *
xmalloc (size)
     int size;
{
  char *result = malloc (((unsigned) size));
  if (result == ((char *) NULL))
    fatal ("virtual memory exhausted", 0);
  return result;
}

static char *
xrealloc (ptr, size)
     char *ptr;
     int size;
{
  char *result = realloc (ptr, ((unsigned) size));
  if (result == ((char *) NULL))
    fatal ("virtual memory exhausted");
  return result;
}

/* Initialize a linebuffer for use */

void
init_linebuffer (linebuffer)
     struct linebuffer *linebuffer;
{
  linebuffer->size = INITIAL_LINE_SIZE;
  linebuffer->buffer = ((char *) xmalloc (INITIAL_LINE_SIZE));
}

/* Read a line of text from `stream' into `linebuffer'.
 * Return the length of the line.  
 */

long
readline (linebuffer, stream)
     struct linebuffer *linebuffer;
     FILE *stream;
{
  char *buffer = linebuffer->buffer;
  char *p = linebuffer->buffer;
  char *end = p + linebuffer->size;

  while (true)
    {
      int c = getc (stream);
      if (p == end)
	{
	  linebuffer->size *= 2;
	  buffer = ((char *) xrealloc (buffer, linebuffer->size));
	  p += buffer - linebuffer->buffer;
	  end += buffer - linebuffer->buffer;
	  linebuffer->buffer = buffer;
	}
      if (c < 0 || c == '\n')
	{
	  *p = 0;
	  break;
	}
      *p++ = c;
    }

  return p - buffer;
}

char *
get_keyword (field, rest)
     register char *field;
     char **rest;
{
  static char keyword[KEYWORD_SIZE];
  register char *ptr;
  register char c;

  ptr = &keyword[0];
  c = *field++;
  if ((isspace (c)) || (c == ':'))
    return ((char *) NULL);
  *ptr++ = ((islower (c)) ? (toupper (c)) : c);
  while (((c = *field++) != ':') && (!(isspace (c))))
    *ptr++ = ((islower (c)) ? (toupper (c)) : c);
  *ptr++ = '\0';
  while (isspace (c)) c = *field++;
  if (c != ':') return ((char *) NULL);
  *rest = field;
  return &keyword[0];
}

boolean
has_keyword (field)
     char *field;
{
  char *ignored;
  return (get_keyword (field, &ignored) != ((char *) NULL));
}

char *
add_field (the_list, field, where)
     line_list the_list;
     register char *field, *where;
{
  register char c;
  while (true)
    {
      *where++ = ' ';
      while ((c = *field++) != '\0')
	*where++ = ((c == ',') ? ' ' : c);
      if (the_list == NIL) break;
      field = the_list->string;
      the_list = the_list->continuation;
    }
  return where;
}

line_list
make_file_preface ()
{
  char *the_string, *temp;
  long idiotic_interface;
  long prefix_length;
  long user_length;
  long date_length;
  line_list result;

  prefix_length = strlen (FROM_PREFIX);
  time (&idiotic_interface);
  the_date = ctime (&idiotic_interface);
  /* the_date has an unwanted newline at the end */
  date_length = strlen (the_date) - 1;
  the_date[date_length] = '\0';
  temp = cuserid ((char *) NULL);
  user_length = strlen (temp);
  the_user = alloc_string (user_length + 1);
  strcpy (the_user, temp);
  the_string = alloc_string (3 + prefix_length +
			     user_length +
			     date_length);
  temp = the_string;
  strcpy (temp, FROM_PREFIX);
  temp = &temp[prefix_length];
  *temp++ = ' ';
  strcpy (temp, the_user);
  temp = &temp[user_length];
  *temp++ = ' ';
  strcpy (temp, the_date);
  result = new_list ();
  result->string = the_string;
  result->continuation = ((line_list) NULL);
  return result;
}

void
write_line_list (the_list, the_stream)
     register line_list the_list;
     FILE *the_stream;
{
  for ( ;
      the_list != ((line_list) NULL) ;
      the_list = the_list->continuation)
    {
      fputs (the_list->string, the_stream);
      putc ('\n', the_stream);
    }
  return;
}

int
close_the_streams ()
{
  register stream_list rem;
  for (rem = the_streams;
       rem != ((stream_list) NULL);
       rem = rem->rest_streams)
    no_problems = (no_problems &&
		   (rem->action (rem->handle) == 0));
  the_streams = ((stream_list) NULL);
  return (no_problems ? 0 : 1);
}

void
add_a_stream (the_stream, closing_action)
     FILE *the_stream;
     int (*closing_action)();
{
  stream_list old = the_streams;
  the_streams = new_stream ();
  the_streams->handle = the_stream;
  the_streams->action = closing_action;
  the_streams->rest_streams = old;
  return;
}

int
my_fclose (the_file)
     FILE *the_file;
{
  putc ('\n', the_file);
  fflush (the_file);
  return fclose (the_file);
}

boolean
open_a_file (name)
     char *name;
{
  FILE *the_stream = fopen (name, "a");
  if (the_stream != ((FILE *) NULL))
    {
      add_a_stream (the_stream, my_fclose);
      if (the_user == ((char *) NULL))
	file_preface = make_file_preface ();
      write_line_list (file_preface, the_stream);
      return true;
    }
  return false;
}

void
put_string (s)
     char *s;
{
  register stream_list rem;
  for (rem = the_streams;
       rem != ((stream_list) NULL);
       rem = rem->rest_streams)
    fputs (s, rem->handle);
  return;
}

void
put_line (s)
     char *s;
{
  register stream_list rem;
  for (rem = the_streams;
       rem != ((stream_list) NULL);
       rem = rem->rest_streams)
    {
      fputs (s, rem->handle);
      putc ('\n', rem->handle);
    }
  return;
}

#define mail_error error

void
setup_files (the_list, field)
     register line_list the_list;
     register char *field;
{
  register char *start;
  register char c;
  while (true)
    {
      while (((c = *field) != '\0') &&
	     ((c == ' ') ||
	      (c == '\t') ||
	      (c == ',')))
	field += 1;
      if (c != '\0')
	{
	  start = field;
	  while (((c = *field) != '\0') &&
		 (c != ' ') &&
		 (c != '\t') &&
		 (c != ','))
	    field += 1;
	  *field = '\0';
	  if (!open_a_file (start))
	    mail_error ("Could not open file %s", start);
	  *field = c;
	  if (c != '\0') continue;
	}
      if (the_list == ((line_list) NULL)) return;
      field = the_list->string;
      the_list = the_list->continuation;
    }
}

int
args_size (the_header)
     header the_header;
{
  register header old = the_header;
  register line_list rem;
  register int size = 0;
  do
    {
      char *field;
      register char *keyword = get_keyword (the_header->text->string, &field);
      if ((strcmp (keyword, "TO") == 0) ||
	  (strcmp (keyword, "CC") == 0) ||
	  (strcmp (keyword, "BCC") == 0))
	{
	  size += 1 + strlen (field);
	  for (rem = the_header->text->continuation;
	       rem != NIL;
	       rem = rem->continuation)
	    size += 1 + strlen (rem->string);
	}
      the_header = the_header->next;
    } while (the_header != old);
  return size;
}

parse_header (the_header, where)
     header the_header;
     register char *where;
{
  register header old = the_header;
  do
    {
      char *field;
      register char *keyword = get_keyword (the_header->text->string, &field);
      if (strcmp (keyword, "TO") == 0)
	where = add_field (the_header->text->continuation, field, where);
      else if (strcmp (keyword, "CC") == 0)
	where = add_field (the_header->text->continuation, field, where);
      else if (strcmp (keyword, "BCC") == 0)
	{
	  where = add_field (the_header->text->continuation, field, where);
	  the_header->previous->next = the_header->next;
	  the_header->next->previous = the_header->previous;
	}
      else if (strcmp (keyword, "FCC") == 0)
	setup_files (the_header->text->continuation, field);
      the_header = the_header->next;
    } while (the_header != old);
  *where = '\0';
  return;
}
    
header
read_header ()
{
  register header the_header = ((header) NULL);
  register line_list *next_line = ((line_list *) NULL);

  init_linebuffer (&lb);

  do
    {
      long length;
      register char *line;

      readline (&lb, stdin);
      line = lb.buffer;
      length = strlen (line);
      if (length == 0) break;

      if (has_keyword (line))
	{
	  register header old = the_header;
	  the_header = new_header ();
	  if (old == ((header) NULL))
	    {
	      the_header->next = the_header;
	      the_header->previous = the_header;
	    }
	  else
	    {
	      the_header->previous = old;
	      the_header->next = old->next;
	      old->next = the_header;
	    }
	  next_line = &(the_header->text);
	}

      if (next_line == ((line_list *) NULL))
	{
	  /* Not a valid header */
	  exit (1);
	}
      *next_line = new_list ();
      (*next_line)->string = alloc_string (length);
      strcpy (((*next_line)->string), line);
      next_line = &((*next_line)->continuation);
      *next_line = NIL;

    } while (true);

  return the_header->next;
}

void
write_header (the_header)
     header the_header;
{
  register header old = the_header;
  do
    {
      register line_list the_list;
      for (the_list = the_header->text;
	   the_list != NIL;
	   the_list = the_list->continuation)
	put_line (the_list->string);
      the_header = the_header->next;
    } while (the_header != old);
  put_line ("");
  return;
}

void
main (argc, argv)
     int argc;
     char **argv;
{
  char *command_line;
  header the_header;
  long name_length = strlen (PROGRAM_NAME);
  char buf[BUFLEN + 1];
  register int size;
  FILE *the_pipe;

  my_name = MY_NAME;
  the_streams = ((stream_list) NULL);
  the_date = ((char *) NULL);
  the_user = ((char *) NULL);

  the_header = read_header ();
  command_line = alloc_string (name_length + args_size (the_header));
  strcpy (command_line, PROGRAM_NAME);
  parse_header (the_header, &command_line[name_length]);
  
  the_pipe = popen (command_line, "w");
  if (the_pipe == ((FILE *) NULL))
    fatal ("cannot open pipe to real mailer");

  add_a_stream (the_pipe, pclose);

  write_header (the_header);

  /* Dump the message itself */

  while (!feof (stdin))
    {
      size = fread (buf, 1, BUFLEN, stdin);
      buf[size] = '\0';
      put_string (buf);
    }

  exit (close_the_streams ());
}

#endif /* not BSD 4.2 (or newer) */