maildir2mbox.c

linux下qmail的源码 本人加了一些注释

//实用工具程序之一，作用：将在maildir格式邮箱中的消息转换到一个标准的sendmail邮箱中

#include "readwrite.h"
#include "prioq.h"
#include "env.h"
#include "stralloc.h"
#include "subfd.h"
#include "substdio.h"
#include "getln.h"
#include "error.h"
#include "open.h"
#include "lock.h"
#include "gfrom.h"
#include "str.h"
#include "exit.h"
#include "myctime.h"
#include "maildir.h"

char *mbox;
char *mboxtmp;

stralloc filenames = {0};
prioq pq = {0};
prioq pq2 = {0};

stralloc line = {0};

stralloc ufline = {0};

char inbuf[SUBSTDIO_INSIZE];
char outbuf[SUBSTDIO_OUTSIZE];

#define FATAL "maildir2mbox: fatal: "
#define WARNING "maildir2mbox: warning: "

void die_nomem() { strerr_die2x(111,FATAL,"out of memory"); }

void main()
{
 substdio ssin;
 substdio ssout;
 struct prioq_elt pe;
 int fdoldmbox;
 int fdnewmbox;
 int fd;
 int match;
 int fdlock;

 umask(077);

 mbox = env_get("MAIL");
 if (!mbox) strerr_die2x(111,FATAL,"MAIL not set");
 mboxtmp = env_get("MAILTMP");
 if (!mboxtmp) strerr_die2x(111,FATAL,"MAILTMP not set");

 if (maildir_chdir() == -1)
   strerr_die1(111,FATAL,&maildir_chdir_err);
 maildir_clean(&filenames);
 if (maildir_scan(&pq,&filenames,1,1) == -1)
   strerr_die1(111,FATAL,&maildir_scan_err);

 if (!prioq_min(&pq,&pe)) _exit(0); /* nothing new */

 fdlock = open_append(mbox);
 if (fdlock == -1)
   strerr_die4sys(111,FATAL,"unable to lock ",mbox,": ");
 if (lock_ex(fdlock) == -1)
   strerr_die4sys(111,FATAL,"unable to lock ",mbox,": ");

 fdoldmbox = open_read(mbox);
 if (fdoldmbox == -1)
   strerr_die4sys(111,FATAL,"unable to read ",mbox,": ");

 fdnewmbox = open_trunc(mboxtmp);
 if (fdnewmbox == -1)
   strerr_die4sys(111,FATAL,"unable to create ",mboxtmp,": ");

 substdio_fdbuf(&ssin,read,fdoldmbox,inbuf,sizeof(inbuf));
 substdio_fdbuf(&ssout,write,fdnewmbox,outbuf,sizeof(outbuf));

 switch(substdio_copy(&ssout,&ssin))
  {
   case -2: strerr_die4sys(111,FATAL,"unable to read ",mbox,": ");
   case -3: strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
  }

 while (prioq_min(&pq,&pe))
  {
   prioq_delmin(&pq);
   if (!prioq_insert(&pq2,&pe)) die_nomem();

   fd = open_read(filenames.s + pe.id);
   if (fd == -1)
     strerr_die4sys(111,FATAL,"unable to read $MAILDIR/",filenames.s + pe.id,": ");
   substdio_fdbuf(&ssin,read,fd,inbuf,sizeof(inbuf));

   if (getln(&ssin,&line,&match,'\n') != 0)
     strerr_die4sys(111,FATAL,"unable to read $MAILDIR/",filenames.s + pe.id,": ");
   
   if (!stralloc_copys(&ufline,"From XXX ")) die_nomem();
   if (match)
     if (stralloc_starts(&line,"Return-Path: <"))
      {
       if (line.s[14] == '>')
	{
         if (!stralloc_copys(&ufline,"From MAILER-DAEMON ")) die_nomem();
	}
       else
	{
	 int i;
         if (!stralloc_ready(&ufline,line.len)) die_nomem();
         if (!stralloc_copys(&ufline,"From ")) die_nomem();
	 for (i = 14;i < line.len - 2;++i)
	   if ((line.s[i] == ' ') || (line.s[i] == '\t'))
	     ufline.s[ufline.len++] = '-';
	   else
	     ufline.s[ufline.len++] = line.s[i];
         if (!stralloc_cats(&ufline," ")) die_nomem();
	}
      }
   if (!stralloc_cats(&ufline,myctime(pe.dt))) die_nomem();
   if (substdio_put(&ssout,ufline.s,ufline.len) == -1)
     strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");

   while (match && line.len)
    {
     if (gfrom(line.s,line.len))
       if (substdio_puts(&ssout,">") == -1)
         strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
     if (substdio_put(&ssout,line.s,line.len) == -1)
       strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
     if (!match)
      {
       if (substdio_puts(&ssout,"\n") == -1)
         strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
       break;
      }
     if (getln(&ssin,&line,&match,'\n') != 0)
       strerr_die4sys(111,FATAL,"unable to read $MAILDIR/",filenames.s + pe.id,": ");
    }
   if (substdio_puts(&ssout,"\n"))
     strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");

   close(fd);
  }

 if (substdio_flush(&ssout) == -1)
   strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
 if (fsync(fdnewmbox) == -1)
   strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
 if (close(fdnewmbox) == -1) /* NFS dorks */
   strerr_die4sys(111,FATAL,"unable to write to ",mboxtmp,": ");
 if (rename(mboxtmp,mbox) == -1)
   strerr_die6(111,FATAL,"unable to move ",mboxtmp," to ",mbox,": ",&strerr_sys);
 
 while (prioq_min(&pq2,&pe))
  {
   prioq_delmin(&pq2);
   if (unlink(filenames.s + pe.id) == -1)
     strerr_warn4(WARNING,"$MAILDIR/",filenames.s + pe.id," will be delivered twice; unable to unlink: ",&strerr_sys);
  }

 _exit(0);
}