qmail-lspawn.c

linux下qmail的源码 本人加了一些注释

//qmail-lspawn由qmail-send调用，qmail-send判断邮件是发给谁的，发给本地的，就交给
//qmail-lspawn程序，再由qmail-local投送到本地邮件服务器

#include "fd.h"
#include "wait.h"
#include "prot.h"
#include "substdio.h"
#include "stralloc.h"
#include "scan.h"
#include "exit.h"
#include "fork.h"
#include "error.h"
#include "cdb.h"
#include "case.h"
#include "slurpclose.h"
#include "auto_qmail.h"
#include "auto_uids.h"
#include "qlx.h"

char *aliasempty;

void initialize(argc,argv)
int argc;
char **argv;
{
  aliasempty = argv[1];
  if (!aliasempty) _exit(100);
}

int truncreport = 3000;

void report(ss,wstat,s,len)
substdio *ss;
int wstat;
char *s;
int len;
{
 int i;
 if (wait_crashed(wstat))
  { substdio_puts(ss,"Zqmail-local crashed.\n"); return; }
 switch(wait_exitcode(wstat))
  {
   case QLX_CDB:
     substdio_puts(ss,"ZTrouble reading users/cdb in qmail-lspawn.\n"); return;
   case QLX_NOMEM:
     substdio_puts(ss,"ZOut of memory in qmail-lspawn.\n"); return;
   case QLX_SYS:
     substdio_puts(ss,"ZTemporary failure in qmail-lspawn.\n"); return;
   case QLX_NOALIAS:
     substdio_puts(ss,"ZUnable to find alias user!\n"); return;
   case QLX_ROOT:
     substdio_puts(ss,"ZNot allowed to perform deliveries as root.\n"); return;
   case QLX_USAGE:
     substdio_puts(ss,"ZInternal qmail-lspawn bug.\n"); return;
   case QLX_NFS:
     substdio_puts(ss,"ZNFS failure in qmail-local.\n"); return;
   case QLX_EXECHARD:
     substdio_puts(ss,"DUnable to run qmail-local.\n"); return;
   case QLX_EXECSOFT:
     substdio_puts(ss,"ZUnable to run qmail-local.\n"); return;
   case QLX_EXECPW:
     substdio_puts(ss,"ZUnable to run qmail-getpw.\n"); return;
   case 111: case 71: case 74: case 75:
     substdio_put(ss,"Z",1); break;
   case 0:
     substdio_put(ss,"K",1); break;
   case 100:
   default:
     substdio_put(ss,"D",1); break;
  }

 for (i = 0;i < len;++i) if (!s[i]) break;
 substdio_put(ss,s,i);
}

stralloc lower = {0};
stralloc nughde = {0};
stralloc wildchars = {0};

void nughde_get(local)
char *local;
{
 char *(args[3]);
 int pi[2];
 int gpwpid;
 int gpwstat;
 int r;
 int fd;
 int flagwild;

 if (!stralloc_copys(&lower,"!")) _exit(QLX_NOMEM);
 if (!stralloc_cats(&lower,local)) _exit(QLX_NOMEM);
 if (!stralloc_0(&lower)) _exit(QLX_NOMEM);
 case_lowerb(lower.s,lower.len);

 if (!stralloc_copys(&nughde,"")) _exit(QLX_NOMEM);

 fd = open_read("users/cdb");
 if (fd == -1)
   if (errno != error_noent)
     _exit(QLX_CDB);

 if (fd != -1)
  {
   uint32 dlen;
   unsigned int i;

   r = cdb_seek(fd,"",0,&dlen);
   if (r != 1) _exit(QLX_CDB);
   if (!stralloc_ready(&wildchars,(unsigned int) dlen)) _exit(QLX_NOMEM);
   wildchars.len = dlen;
   if (cdb_bread(fd,wildchars.s,wildchars.len) == -1) _exit(QLX_CDB);

   i = lower.len;
   flagwild = 0;

   do
    {
     /* i > 0 */
     if (!flagwild || (i == 1) || (byte_chr(wildchars.s,wildchars.len,lower.s[i - 1]) < wildchars.len))
      {
       r = cdb_seek(fd,lower.s,i,&dlen);
       if (r == -1) _exit(QLX_CDB);
       if (r == 1)
        {
         if (!stralloc_ready(&nughde,(unsigned int) dlen)) _exit(QLX_NOMEM);
         nughde.len = dlen;
         if (cdb_bread(fd,nughde.s,nughde.len) == -1) _exit(QLX_CDB);
         if (flagwild)
	   if (!stralloc_cats(&nughde,local + i - 1)) _exit(QLX_NOMEM);
         if (!stralloc_0(&nughde)) _exit(QLX_NOMEM);
         close(fd);
         return;
        }
      }
     --i;
     flagwild = 1;
    }
   while (i);

   close(fd);
  }

 if (pipe(pi) == -1) _exit(QLX_SYS);
 args[0] = "bin/qmail-getpw";
 args[1] = local;
 args[2] = 0;
 switch(gpwpid = vfork())
  {
   case -1:
     _exit(QLX_SYS);
   case 0:
     if (prot_gid(auto_gidn) == -1) _exit(QLX_USAGE);
     if (prot_uid(auto_uidp) == -1) _exit(QLX_USAGE);
     close(pi[0]);
     if (fd_move(1,pi[1]) == -1) _exit(QLX_SYS);
     execv(*args,args);
     _exit(QLX_EXECPW);
  }
 close(pi[1]);

 if (slurpclose(pi[0],&nughde,128) == -1) _exit(QLX_SYS);

 if (wait_pid(&gpwstat,gpwpid) != -1)
  {
   if (wait_crashed(gpwstat)) _exit(QLX_SYS);
   if (wait_exitcode(gpwstat) != 0) _exit(wait_exitcode(gpwstat));
  }
}

int spawn(fdmess,fdout,s,r,at)
int fdmess; int fdout;
char *s; char *r; int at;
{
 int f;

 if (!(f = fork()))
  {
   char *(args[11]);
   unsigned long u;
   int n;
   int uid;
   int gid;
   char *x;
   unsigned int xlen;
   
   r[at] = 0;
   if (!r[0]) _exit(0); /* <> */

   if (chdir(auto_qmail) == -1) _exit(QLX_USAGE);

   nughde_get(r);

   x = nughde.s;
   xlen = nughde.len;

   args[0] = "bin/qmail-local";
   args[1] = "--";
   args[2] = x;
   n = byte_chr(x,xlen,0); if (n++ == xlen) _exit(QLX_USAGE); x += n; xlen -= n;

   scan_ulong(x,&u);
   uid = u;
   n = byte_chr(x,xlen,0); if (n++ == xlen) _exit(QLX_USAGE); x += n; xlen -= n;

   scan_ulong(x,&u);
   gid = u;
   n = byte_chr(x,xlen,0); if (n++ == xlen) _exit(QLX_USAGE); x += n; xlen -= n;

   args[3] = x;
   n = byte_chr(x,xlen,0); if (n++ == xlen) _exit(QLX_USAGE); x += n; xlen -= n;

   args[4] = r;
   args[5] = x;
   n = byte_chr(x,xlen,0); if (n++ == xlen) _exit(QLX_USAGE); x += n; xlen -= n;

   args[6] = x;
   n = byte_chr(x,xlen,0); if (n++ == xlen) _exit(QLX_USAGE); x += n; xlen -= n;

   args[7] = r + at + 1;
   args[8] = s;
   args[9] = aliasempty;
   args[10] = 0;

   if (fd_move(0,fdmess) == -1) _exit(QLX_SYS);
   if (fd_move(1,fdout) == -1) _exit(QLX_SYS);
   if (fd_copy(2,1) == -1) _exit(QLX_SYS);
   if (prot_gid(gid) == -1) _exit(QLX_USAGE);
   if (prot_uid(uid) == -1) _exit(QLX_USAGE);
   if (!getuid()) _exit(QLX_ROOT);

   execv(*args,args);
   if (error_temp(errno)) _exit(QLX_EXECSOFT);
   _exit(QLX_EXECHARD);
  }
 return f;
}