qmail-local.c

linux下qmail的源码 本人加了一些注释

//向本地邮件系统上的用户投递消息

#include <sys/types.h>
#include <sys/stat.h>
#include "readwrite.h"
#include "sig.h"
#include "env.h"
#include "byte.h"
#include "exit.h"
#include "fork.h"
#include "open.h"
#include "wait.h"
#include "lock.h"
#include "seek.h"
#include "substdio.h"
#include "getln.h"
#include "strerr.h"
#include "subfd.h"
#include "sgetopt.h"
#include "alloc.h"
#include "error.h"
#include "stralloc.h"
#include "fmt.h"
#include "str.h"
#include "now.h"
#include "case.h"
#include "quote.h"
#include "qmail.h"
#include "slurpclose.h"
#include "myctime.h"
#include "gfrom.h"
#include "auto_patrn.h"

void usage() { strerr_die1x(100,"qmail-local: usage: qmail-local [ -nN ] user homedir local dash ext domain sender aliasempty"); }

void temp_nomem() { strerr_die1x(111,"Out of memory. (#4.3.0)"); }
void temp_rewind() { strerr_die1x(111,"Unable to rewind message. (#4.3.0)"); }
void temp_childcrashed() { strerr_die1x(111,"Aack, child crashed. (#4.3.0)"); }
void temp_fork() { strerr_die3x(111,"Unable to fork: ",error_str(errno),". (#4.3.0)"); }
void temp_read() { strerr_die3x(111,"Unable to read message: ",error_str(errno),". (#4.3.0)"); }
void temp_slowlock()
{ strerr_die1x(111,"File has been locked for 30 seconds straight. (#4.3.0)"); }
void temp_qmail(fn) char *fn;
{ strerr_die5x(111,"Unable to open ",fn,": ",error_str(errno),". (#4.3.0)"); }

int flagdoit;
int flag99;

char *user;
char *homedir;
char *local;
char *dash;
char *ext;
char *host;
char *sender;
char *aliasempty;

stralloc safeext = {0};
stralloc ufline = {0};
stralloc rpline = {0};
stralloc envrecip = {0};
stralloc dtline = {0};
stralloc qme = {0};
stralloc ueo = {0};
stralloc cmds = {0};
stralloc messline = {0};
stralloc foo = {0};

char buf[1024];
char outbuf[1024];

/* child process */

char fntmptph[80 + FMT_ULONG * 2];
char fnnewtph[80 + FMT_ULONG * 2];
void tryunlinktmp() { unlink(fntmptph); }
void sigalrm() { tryunlinktmp(); _exit(3); }

void maildir_child(dir)
char *dir;
{
 unsigned long pid;
 unsigned long time;
 char host[64];
 char *s;
 int loop;
 struct stat st;
 int fd;
 substdio ss;
 substdio ssout;

 sig_alarmcatch(sigalrm);
 if (chdir(dir) == -1) { if (error_temp(errno)) _exit(1); _exit(2); }
 pid = getpid();
 host[0] = 0;
 gethostname(host,sizeof(host));
 for (loop = 0;;++loop)
  {
   time = now();
   s = fntmptph;
   s += fmt_str(s,"tmp/");
   s += fmt_ulong(s,time); *s++ = '.';
   s += fmt_ulong(s,pid); *s++ = '.';
   s += fmt_strn(s,host,sizeof(host)); *s++ = 0;
   if (stat(fntmptph,&st) == -1) if (errno == error_noent) break;
   /* really should never get to this point */
   if (loop == 2) _exit(1);
   sleep(2);
  }
 str_copy(fnnewtph,fntmptph);
 byte_copy(fnnewtph,3,"new");

 alarm(86400);
 fd = open_excl(fntmptph);
 if (fd == -1) _exit(1);

 substdio_fdbuf(&ss,read,0,buf,sizeof(buf));
 substdio_fdbuf(&ssout,write,fd,outbuf,sizeof(outbuf));
 if (substdio_put(&ssout,rpline.s,rpline.len) == -1) goto fail;
 if (substdio_put(&ssout,dtline.s,dtline.len) == -1) goto fail;

 switch(substdio_copy(&ssout,&ss))
  {
   case -2: tryunlinktmp(); _exit(4);
   case -3: goto fail;
  }

 if (substdio_flush(&ssout) == -1) goto fail;
 if (fsync(fd) == -1) goto fail;
 if (close(fd) == -1) goto fail; /* NFS dorks */

 if (link(fntmptph,fnnewtph) == -1) goto fail;
   /* if it was error_exist, almost certainly successful; i hate NFS */
 tryunlinktmp(); _exit(0);

 fail: tryunlinktmp(); _exit(1);
}

/* end child process */

void maildir(fn)
char *fn;
{
 int child;
 int wstat;

 if (seek_begin(0) == -1) temp_rewind();

 switch(child = fork())
  {
   case -1:
     temp_fork();
   case 0:
     maildir_child(fn);
     _exit(111);
  }

 wait_pid(&wstat,child);
 if (wait_crashed(wstat))
   temp_childcrashed();
 switch(wait_exitcode(wstat))
  {
   case 0: break;
   case 2: strerr_die1x(111,"Unable to chdir to maildir. (#4.2.1)");
   case 3: strerr_die1x(111,"Timeout on maildir delivery. (#4.3.0)");
   case 4: strerr_die1x(111,"Unable to read message. (#4.3.0)");
   default: strerr_die1x(111,"Temporary error on maildir delivery. (#4.3.0)");
  }
}

void mailfile(fn)
char *fn;
{
 int fd;
 substdio ss;
 substdio ssout;
 int match;
 seek_pos pos;
 int flaglocked;

 if (seek_begin(0) == -1) temp_rewind();

 fd = open_append(fn);
 if (fd == -1)
   strerr_die5x(111,"Unable to open ",fn,": ",error_str(errno),". (#4.2.1)");

 sig_alarmcatch(temp_slowlock);
 alarm(30);
 flaglocked = (lock_ex(fd) != -1);
 alarm(0);
 sig_alarmdefault();

 seek_end(fd);
 pos = seek_cur(fd);

 substdio_fdbuf(&ss,read,0,buf,sizeof(buf));
 substdio_fdbuf(&ssout,write,fd,outbuf,sizeof(outbuf));
 if (substdio_put(&ssout,ufline.s,ufline.len)) goto writeerrs;
 if (substdio_put(&ssout,rpline.s,rpline.len)) goto writeerrs;
 if (substdio_put(&ssout,dtline.s,dtline.len)) goto writeerrs;
 for (;;)
  {
   if (getln(&ss,&messline,&match,'\n') != 0) 
    {
     strerr_warn3("Unable to read message: ",error_str(errno),". (#4.3.0)",0);
     if (flaglocked) seek_trunc(fd,pos); close(fd);
     _exit(111);
    }
   if (!match && !messline.len) break;
   if (gfrom(messline.s,messline.len))
     if (substdio_bput(&ssout,">",1)) goto writeerrs;
   if (substdio_bput(&ssout,messline.s,messline.len)) goto writeerrs;
   if (!match)
    {
     if (substdio_bputs(&ssout,"\n")) goto writeerrs;
     break;
    }
  }
 if (substdio_bputs(&ssout,"\n")) goto writeerrs;
 if (substdio_flush(&ssout)) goto writeerrs;
 if (fsync(fd) == -1) goto writeerrs;
 close(fd);
 return;

 writeerrs:
 strerr_warn5("Unable to write ",fn,": ",error_str(errno),". (#4.3.0)",0);
 if (flaglocked) seek_trunc(fd,pos);
 close(fd);
 _exit(111);
}

void mailprogram(prog)
char *prog;
{
 int child;
 char *(args[4]);
 int wstat;

 if (seek_begin(0) == -1) temp_rewind();

 switch(child = fork())
  {
   case -1:
     temp_fork();
   case 0:
     args[0] = "/bin/sh"; args[1] = "-c"; args[2] = prog; args[3] = 0;
     sig_pipedefault();
     execv(*args,args);
     strerr_die3x(111,"Unable to run /bin/sh: ",error_str(errno),". (#4.3.0)");
  }

 wait_pid(&wstat,child);
 if (wait_crashed(wstat))
   temp_childcrashed();
 switch(wait_exitcode(wstat))
  {
   case 100:
   case 64: case 65: case 70: case 76: case 77: case 78: case 112: _exit(100);
   case 0: break;
   case 99: flag99 = 1; break;
   default: _exit(111);
  }
}

unsigned long mailforward_qp = 0;

void mailforward(recips)
char **recips;
{
 struct qmail qqt;
 char *qqx;
 substdio ss;
 int match;

 if (seek_begin(0) == -1) temp_rewind();
 substdio_fdbuf(&ss,read,0,buf,sizeof(buf));

 if (qmail_open(&qqt) == -1) temp_fork();
 mailforward_qp = qmail_qp(&qqt);
 qmail_put(&qqt,dtline.s,dtline.len);
 do
  {
   if (getln(&ss,&messline,&match,'\n') != 0) { qmail_fail(&qqt); break; }
   qmail_put(&qqt,messline.s,messline.len);
  }
 while (match);
 qmail_from(&qqt,ueo.s);
 while (*recips) qmail_to(&qqt,*recips++);
 qqx = qmail_close(&qqt);
 if (!*qqx) return;
 strerr_die3x(*qqx == 'D' ? 100 : 111,"Unable to forward message: ",qqx + 1,".");
}

void bouncexf()
{
 int match;
 substdio ss;

 if (seek_begin(0) == -1) temp_rewind();
 substdio_fdbuf(&ss,read,0,buf,sizeof(buf));
 for (;;)
  {
   if (getln(&ss,&messline,&match,'\n') != 0) temp_read();
   if (!match) break;
   if (messline.len <= 1)
     break;
   if (messline.len == dtline.len)
     if (!str_diffn(messline.s,dtline.s,dtline.len))
       strerr_die1x(100,"This message is looping: it already has my Delivered-To line. (#5.4.6)");
  }
}

void checkhome()
{
 struct stat st;

 if (stat(".",&st) == -1)
   strerr_die3x(111,"Unable to stat home directory: ",error_str(errno),". (#4.3.0)");
 if (st.st_mode & auto_patrn)
   strerr_die1x(111,"Uh-oh: home directory is writable. (#4.7.0)");
 if (st.st_mode & 01000)
   if (flagdoit)
     strerr_die1x(111,"Home directory is sticky: user is editing his .qmail file. (#4.2.1)");
   else
     strerr_warn1("Warning: home directory is sticky.",0);
}

int qmeox(dashowner)
char *dashowner;
{
 struct stat st;

 if (!stralloc_copys(&qme,".qmail")) temp_nomem();
 if (!stralloc_cats(&qme,dash)) temp_nomem();
 if (!stralloc_cat(&qme,&safeext)) temp_nomem();
 if (!stralloc_cats(&qme,dashowner)) temp_nomem();
 if (!stralloc_0(&qme)) temp_nomem();
 if (stat(qme.s,&st) == -1)
  {
   if (error_temp(errno)) temp_qmail(qme.s);
   return -1;
  }
 return 0;
}

int qmeexists(fd,cutable)
int *fd;
int *cutable;
{
  struct stat st;