/* Mixmaster version 3.0  --  (C) 1999 - 2004 Anonymizer Inc. and others.

   Mixmaster may be redistributed and modified under certain conditions.
   This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
   ANY KIND, either express or implied. See the file COPYRIGHT for
   details.

   Maildir support routines
   $Id: $ */


/* Maildir support for Mixmaster 3 - see
   http://www.qmail.org/man/man5/maildir.html and
   http://cr.yp.to/proto/maildir.html

   Added by and (C) 2001 Doobee R. Tzeck 
   drt@un.bewaff.net - http://c0re.jp/

   To test it try:
   $ gcc maildir.c -DUNITTEST -o test_maildir
   $ ./test_maildir
   this should print a single line saying "OK"
*/

#include "mix3.h"

#ifdef WIN32
#include <io.h>
#include <direct.h>
#include <process.h>
#define S_IWUSR _S_IWRITE
#define S_IRUSR _S_IREAD
#else /* end of WIN32 */
#include <unistd.h>
#endif /* else not WIN32 */
#include <fcntl.h>
#include <time.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <stdarg.h>
#include <assert.h>

#if defined(S_IFDIR) && !defined(S_ISDIR)
#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif /* defined(S_IFDIR) && !defined(S_ISDIR) */

#ifndef SHORTNAMES

static unsigned long namecounter = 0;

int checkDirectory(char *dir, char *append, int create) {
  char tmp[PATHMAX];
  struct stat buf;
  int err;

  tmp[0] = '\0';
  strcatn(tmp, dir, PATHMAX);
  if (append)
    strcatn(tmp, append, PATHMAX);

  err = stat(tmp, &buf);
  if (err == -1) {
    if (create) {
#ifndef POSIX
      err = mkdir(tmp);
#else /* end of not POSIX */
      err = mkdir(tmp, S_IRWXU);
#endif /* else if POSIX */
      if (err == 0)
	errlog(NOTICE, "Creating directory %s.\n", tmp);
    } else
      err = 1;
  } else if (!S_ISDIR(buf.st_mode))
    err = -1;

  return err;
}

/* Write "message" to "maildir", retunr 0 on success, -1 on failure */
#define MAX_BASENAME 113 /* actual length should be smaller than 111 bytes */
#define MAX_SUBNAME 123 /* actual length should be smaller than 115 bytes */
int maildirWrite(char *maildir, BUFFER *message, int create) {
  int fd;
  int count;
  int returnValue;
  char hostname[64];
  struct stat statbuf;
  char basename[MAX_BASENAME];
  char tmpname[MAX_SUBNAME];
  char newname[MAX_SUBNAME];
  int messagesize;
  char olddirectory[PATHMAX] = "";
  char normalizedmaildir[PATHMAX];

  /* Declare a handler for SIGALRM so we can time out. */
  /* set_handler(SIGALRM, alarm_handler);  */
  /* alarm(86400); */

  hostname[0] = '\0';
  gethostname(hostname, 63);
  hostname[63] = '\0';

  mixfile(normalizedmaildir, maildir);
  if ((checkDirectory(normalizedmaildir, NULL, create) != 0) ||
      (checkDirectory(normalizedmaildir, "tmp", create) != 0) ||
      (checkDirectory(normalizedmaildir, "cur", create) != 0) ||
      (checkDirectory(normalizedmaildir, "new", create) != 0)) {
    returnValue = -1;
    goto realend;
  }

  messagesize = message->length;

  /* Step 1: chdir to maildir (and save current dir) */
  if (getcwd(olddirectory, PATHMAX) == NULL) {
    returnValue = -1;
    goto realend;
  }
  olddirectory[PATHMAX-1] = '\0';
  if(chdir(normalizedmaildir) != 0) {
    returnValue = -1;
    goto functionExit;
  }

  /* Step 2:  Stat the temporary file.  Wait for ENOENT as a response. */
  for (count = 0;; count++) {
    tmpname[0] = '\0';
    newname[0] = '\0';
    snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
      time(NULL), getpid(), namecounter++, hostname, messagesize);
    basename[MAX_BASENAME-1] = '\0';
    strcatn(tmpname, "tmp" DIRSEPSTR, MAX_SUBNAME);
    strcatn(tmpname, basename, MAX_SUBNAME);
    strcatn(newname, "new" DIRSEPSTR, MAX_SUBNAME);
    strcatn(newname, basename, MAX_SUBNAME);

    if (stat(tmpname, &statbuf) == 0)
      errno = EEXIST;
    else if (errno == ENOENT) {
      /* Step 4: create the file (at least try) */
      fd = open(tmpname, O_WRONLY|O_CREAT|O_EXCL, S_IWUSR|S_IRUSR);
      if (fd >= 0)
	break; /* we managed to open the file */
    }

    if (count > 5) {
      /* Too many retries - give up */
      errlog(ERRORMSG, "Can't create message in %s\n", maildir);
      returnValue = -1;
      goto functionExit;
    }

    /* Step 3: sleep and retry */
    sleep(2);
  }

  /* Step 5:  write file */
  if(write(fd, message->data, message->length) != message->length) {
    returnValue = -1;
    goto functionExit;
  }

  /* on NFS this could fail */
#ifndef WIN32
  if((fsync(fd) != 0) || (close(fd) != 0)) {
#else /* end of not WIN32 */
  if((_commit(fd) != 0) || (close(fd) != 0)) {
#endif /* else if WIN32 */
    returnValue = -1;
    goto functionExit;
  }

  /* Step 6: move message to 'cur' */
#ifdef POSIX
  for (count = 0;; count++) {
    if(link(tmpname, newname) != 0) {
      if (errno == EXDEV || errno == EPERM) {
	/* We probably are on coda or some other filesystem that does not allow
	 * hardlinks. rename() the file instead of link() and unlink()
	 * I know, It's evil (PP).
	 */
	if (rename(tmpname, newname) != 0) {
	  returnValue = -1;
	  goto functionExit;
	};
	break;
      } else if (errno != EEXIST) {
	returnValue = -1;
	goto functionExit;
      }
    } else {
      /* We successfully linked the message in new/. Now let's get
       * rid of our tmp/ entry
       */
      if(unlink(tmpname) != 0) {
	/* unlinking failed */
	returnValue = -1;
	goto functionExit;
      }
      break;
    }

    if (count > 5) {
      /* Too many retries - give up */
      errlog(ERRORMSG, "Can't move message to %s/new/\n", maildir);
      returnValue = -1;
      goto functionExit;
    }

    sleep(2);
    newname[0] = '\0';
    snprintf(basename, MAX_BASENAME, "%lu.%u_%lu.%s,S=%u",
      time(NULL), getpid(), namecounter++, hostname, messagesize);
    basename[MAX_BASENAME-1] = '\0';
    strcatn(newname, "new" DIRSEPSTR, MAX_SUBNAME);
    strcatn(newname, basename, MAX_SUBNAME);
  }
#else /* end of POSIX */
  /* On non POSIX systems we simply use rename(). Let's hope DJB
   * never finds out
   */
  if (rename(tmpname, newname) != 0) {
    returnValue = -1;
    goto functionExit;
  };
#endif /* else if not POSIX */

  returnValue = 0;

functionExit:
  /* return to original directory */
  assert(olddirectory[0] != '\0');
  if(chdir(olddirectory) != 0)
    returnValue = -1;

realend:

  return returnValue;
}

#else /* end of SHORTNAMES */
int maildirWrite(char *maildir, BUFFER *message, int create) {
{
  errlog(ERRORMSG, "Maildir delivery does not work with SHORTNAMES.\n");
  return -1;
}
#endif /* else if not SHORTNAMES */


#ifdef UNITTEST

#ifdef NDEBUG
#undef NDEBUG
#endif /* NDEBUG */

#include <dirent.h>

/* mock-up of errlog for unittest */
void errlog(int type, char *fmt,...)
{
  va_list ap;

  va_start(ap, fmt);
  vfprintf(stderr, fmt, ap);
  va_end(ap);
}

/* main for unittest */
int main()
{
  int i, count = 23;
  int fd;
  DIR *d;
  struct dirent *de;
  BUFFER message;
  char text[] = "From: nobody@un.bewaff.net\nTo: hackers@c0re.jp\nSubject: testing\n\nthis is just a test\n";
  char buf[1024];

  /* create buffer with test data */
  message.data = text;
  message.length = strlen(text);

  /* write <count> messages to maildir */
  for(i = 0; i < count; i++)
    assert(maildirWrite("Maildir.test_maildir", message, 1) == 0);

  /* read them back */
  assert((d = opendir("Maildir.test_maildir/new")) != NULL);
  for (i = 0; i < count + 2; i++)
    {
      de = readdir(d);
      if(de->d_name[0] != '.')
	{
	  buf[0] = '\0';
	  strcat(buf, "Maildir.test_maildir/new/");
	  strcat(buf, de->d_name);
	  fd = open(buf, O_RDONLY);
	  assert(unlink(buf) == 0);
	  assert(read(fd, buf, strlen(text)) == strlen(text));
	  buf[strlen(text)] = '\0';
	  /* check if they match the original message */
	  assert(strcmp(text, buf) == 0);
	  close(fd);
	}
    }

  /* no files left in directory? */
  assert(readdir(d) == NULL);

  /* delete maildir */
  assert(rmdir("Maildir.test_maildir/tmp") == 0);
  assert(rmdir("Maildir.test_maildir/new") == 0);
  assert(rmdir("Maildir.test_maildir/cur") == 0);
  assert(rmdir("Maildir.test_maildir") == 0);

  /* check if writing to a non existant maildir yilds an error */
  assert(maildirWrite("Maildir.test_maildir", &message, 0) == -1);

  puts("OK");
}
#endif /* UNITTEST */