qmail-queue源代码分析 Programmer:夜未眠 Comefrom:ChongQing Gearbox co.,ltd 程序主要完成的功能是： 1.生成自已的邮件首部，也就是你在邮件头中见到的类似下面的东西 Recevied (qmail 855 invoked by uid 0); 2 May 2003 12:18:09 -0000 2.建立3个文件 queue/mess/ / //邮件正文
queue/intd/ 用户id,进程id,mailfrom,rcptto
queue/todo/ 是intd目录下文件的复本.
3.写命名管道lock/trigger通知新邮件
#define DEATH 86400 /* 24 hours; _must_ be below q-s's OSSIFIED (36 hours) */
#define ADDR 1003
char inbuf[2048];
struct substdio ssin;
char outbuf[256];
struct substdio ssout;
datetime_sec starttime;
struct datetime dt;
unsigned long mypid;
unsigned long uid;
char *pidfn;
struct stat pidst;
unsigned long messnum;
char *messfn;
char *todofn;
char *intdfn;
int messfd;
int intdfd;
int flagmademess = 0;
int flagmadeintd = 0;
//错误清理
void cleanup()
{
if (flagmadeintd)
{
seek_trunc(intdfd,0);
if (unlink(intdfn) == -1) return;
}
if (flagmademess)
{
seek_trunc(messfd,0);
if (unlink(messfn) == -1) return;
}
}
void die(e) int e; { _exit(e); }
void die_write() { cleanup(); die(53); }
void die_read() { cleanup(); die(54); }
void sigalrm() { /* thou shalt not clean up here */ die(52); }
void sigbug() { die(81); }
unsigned int receivedlen;
char *received;
static unsigned int receivedfmt(s)
char *s;
{
unsigned int i;
unsigned int len;
len = 0;
/*生成
/* "Received: (qmail-queue invoked by alias); 26 Sep 1995 04:46:54 -0000\n" */
[日 月 年 时 分 秒]
的形式.
*/
i = fmt_str(s,"Received: (qmail "); len += i; if (s) s += i;
i = fmt_ulong(s,mypid); len += i; if (s) s += i;
i = fmt_str(s," invoked "); len += i; if (s) s += i;
if (uid == auto_uida)
{ i = fmt_str(s,"by alias"); len += i; if (s) s += i; }
else if (uid == auto_uidd)
{ i = fmt_str(s,"from network"); len += i; if (s) s += i; }
else if (uid == auto_uids)
{ i = fmt_str(s,"for bounce"); len += i; if (s) s += i; }
else
{
i = fmt_str(s,"by uid "); len += i; if (s) s += i;
i = fmt_ulong(s,uid); len += i; if (s) s += i;
}
i = fmt_str(s,"); "); len += i; if (s) s += i;
i = date822fmt(s,%26amp;dt); len += i; if (s) s += i;
return len;
}
void received_setup()
{
receivedlen = receivedfmt((char *) 0);
received = alloc(receivedlen + 1);
if (!received) die(51);
receivedfmt(received);
}
unsigned int pidfmt(s,seq)
char *s;
unsigned long seq;
{
unsigned int i;
unsigned int len;
//生成类型pid/3434.34242424.1的字符串到s中
//这个字符串实际上就是/var/qmail/queue/pid目录下一个文件名。指示当前进程的pid.
len = 0;
i = fmt_str(s,"pid/"); len += i; if (s) s += i;
i = fmt_ulong(s,mypid); len += i; if (s) s += i;
i = fmt_str(s,"."); len += i; if (s) s += i;
i = fmt_ulong(s,starttime); len += i; if (s) s += i;
i = fmt_str(s,"."); len += i; if (s) s += i;
i = fmt_ulong(s,seq); len += i; if (s) s += i;
++len; if (s) *s++ = 0;
return len;
}
char *fnnum(dirslash,flagsplit)
char *dirslash;
int flagsplit;
{
char *s;
s = alloc(fmtqfn((char *) 0,dirslash,messnum,flagsplit));
if (!s) die(51);
fmtqfn(s,dirslash,messnum,flagsplit);
return s;
}
void pidopen() //建立类似/var/run/inet.pid之类的进程id文件.
{
unsigned int len;
unsigned long seq;
seq = 1;
len = pidfmt((char *) 0,seq);
pidfn = alloc(len);
if (!pidfn) die(51);
for (seq = 1;seq < 10;++seq)
{
if (pidfmt((char *) 0,seq) > len) die(81); /* paranoia */
pidfmt(pidfn,seq);
messfd = open_excl(pidfn);
if (messfd != -1) return;
}
die(63);
}
char tmp[FMT_ULONG];
void main()
{
unsigned int len;
char ch;
sig_blocknone();
umask(033);
if (chdir(auto_qmail) == -1) die(61);
if (chdir("queue") == -1) die(62);//改变工作目录到/var/qmail/queue
mypid = getpid();
uid = getuid();
starttime = now();
datetime_tai(%26amp;dt,starttime);//将起始时间转换为可读年月日时分秒的形式
//生成自已的邮件头存入缓存reseived中
//例如: received="Received: (qmail 3434 invoked by 34434); Apr 27 2003 14:55:34"
received_setup();
sig_pipeignore();
sig_miscignore();
sig_alarmcatch(sigalrm);//捕捉alarm信号,控制超时
sig_bugcatch(sigbug);
alarm(DEATH); //超时秒数，缺省值是86400(24小时) 后错误返回52
pidopen();//建立进程id文件
if (fstat(messfd,%26amp;pidst) == -1) die(63);
messnum = pidst.st_ino; //进程id文件的inode节点号
/*生成将要建立的文件的文件名
几个文件都是根据刚才建立的pid文件的inode节点号命名的.inode不可能被两个文件同时占用，这保证了邮件唯一性。
其中mess目录下的文件放置有一个%23的问题，
tips: 因为是%23所以该目录名最大的可能只有22，明白queue/mess目录下目录为什么最大只22了吧
Tags:分析 源代码 if len char int unsigned // die 文件 fmt_str
|
|
