/***************************************************************************
*
* Copyright 2008 by Sean Conner.
*
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
* Comments, questions and criticisms can be sent to: sean@conman.org
*
*************************************************************************/

/****************************************************************
*
* Wrapper program for sendmail for PHP under Apache (may work
* on other webservers, but untested).
*
* To compile:
*
* 	You'll need to install my cgilib, available at
*	http://www.conman.org/software/cgilib/cgilib.tar.gz
*
* Then:
*
*  gcc -Wall -ansi -pedantic -o wrapper wrapper.c -lcgi5
*
* Copy the wrapper program somewhere where Apache can execute it,
* then modify /etc/php.ini:
*
*	; For Unix only.  You may supply arguments as well (default: "sendmail -t -i").
*	; sendmail_path = /usr/sbin/sendmail -t -i
*	sendmail_path = /path/to/wrapper -t -i
*
* Restart Apache, and Bob's your uncle.
*
* The wrapper logs information to syslog using the LOG_LOCAL4 facility,
* so you may want to check /etc/syslog.conf to make sure you're 
* logging local4.info (at least) somewhere.
*
******************************************************************/

/********************************************************************
*
* This program was brought to you by a grant from Pick Internet [1], and
* by a grant from HarmonyLogic [2].  Also, by the number 10.
*
* [1]	http://www.pickint.net/
* [2]	http://www.harmonylogic.com/
*
********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <unistd.h>
#include <syslog.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <cgilib/memory.h>
#include <cgilib/ddt.h>
#include <cgilib/stream.h>
#include <cgilib/pair.h>
#include <cgilib/util.h>
#include <cgilib/rfc822.h>

/*******************************************************/

int main(int argc,char *argv[],char *envp[])
{
  List              headers;
  Stream            tmp;
  char             *hostname;
  char             *workdir;
  char             *to;
  char             *cc;
  char             *bcc;
  int               rc;
  pid_t             child;
  char              tmpfile[BUFSIZ];
  int               fhin;

  MemInit();
  DdtInit();
  StreamInit();  
  openlog("smw",0,LOG_LOCAL4);

  /*---------------------------------------------------------
  ; copy STDIN to a file.  This copy is used twice, once
  ; to read the headers, then again when we fork() to 
  ; sendmail.
  ;--------------------------------------------------------*/
  
  sprintf(tmpfile,"/tmp/wrapper.%lu",(unsigned long)getpid());
  tmp = FileStreamWrite(tmpfile,FILE_CREATE | FILE_TRUNCATE);
  StreamCopy(tmp,StdinStream);
  StreamFree(tmp);
  
  /*----------------------------------------------------
  ; read in the headers from the email we're sending
  ;----------------------------------------------------*/
  
  tmp = FileStreamRead(tmpfile);
  ListInit(&headers);
  RFC822HeadersRead(tmp,&headers);
  StreamFree(tmp);
  
  hostname = spc_getenv("HOSTNAME");
  workdir  = spc_getenv("PWD");
  to       = PairListGetValue(&headers,"TO");
  cc       = PairListGetValue(&headers,"CC");
  bcc      = PairListGetValue(&headers,"BCC");
  
  syslog(
    LOG_INFO,
    "H: %s W: %s To: %s Cc: %s Bcc: %s",
    hostname,
    workdir,
    to,
    cc,
    bcc
  );
  
  /*--------------------------------------------------
  ; we open the file for read mode---this file then
  ; becomes STDIN for sendmail when we fork()/exec() it
  ;----------------------------------------------------*/
  
  fhin = open(tmpfile,O_RDONLY);
  if (fhin == -1)
  {
    syslog(LOG_CRIT,"open(%s,READ) = %s",tmpfile,strerror(errno));
    exit(EXIT_FAILURE);
  }

  child = fork();
  if (child == (pid_t)-1)
  {
    syslog(LOG_CRIT,"fork() = %s",strerror(errno));
    exit(EXIT_FAILURE);
  }
  
  if (child == 0)	/* child process */
  {
    char **newargv;
    int    i;
    
    /*--------------------------------------------------
    ; while argv[] is writable on Linux, it may not be
    ; on other systems, so just in case, we copy the
    ; array, so we can swap out the name of the program
    ; in argv[0]
    ;-------------------------------------------------*/
    
    newargv = MemAlloc(sizeof(char *) * (argc + 1));
    newargv[0] = "sendmail";
    
    for (i = 1 ; i < argc ; i++)
      newargv[i] = argv[i];
    
    newargv[i] = NULL;
    
    /*-----------------------------------------------
    ; set STDIN to our file, then fork() away
    ;-----------------------------------------------*/
    
    dup2(fhin,STDIN_FILENO);
    rc = execve("/usr/sbin/sendmail",newargv,envp);
    syslog(LOG_CRIT,"execve() = %s",strerror(errno));
    exit(EXIT_FAILURE);
  }
  else			/* parent process */
  {
    pid_t cstat;
    int   status;

    cstat = waitpid(child,&status,0);

    if (WIFEXITED(status))
      rc = WEXITSTATUS(status);
    else
      rc = EXIT_FAILURE;

    unlink(tmpfile);	/* make sure we clean up after ourselves */
    exit(rc);
  }
}