qmail-local程式碼分析(轉)[@more@]

我分析的程式碼沒有“夜未眠”大哥的好，可能還有的不正確，就請各位多多指教，謝謝

程式碼:

#include

#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); }/*刪除fntmptph檔案，或連線*/

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);//捕捉時間訊號。

if (chdir(dir) == -1) { if (error_temp(errno)) _exit(1); _exit(2); }

pid = getpid();//獲取當前的程式號。

host[0] = 0;

gethostname(host,sizeof(host));

for (loop = 0;;++loop)

{

time = now();

s = fntmptph;

s += fmt_str(s,"tmp/");/*將"tmp/"拷到s中*/

s += fmt_ulong(s,time); *s++ = '.';/*將時間轉化為字串*/

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");

//時間為24小時

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));

//dtline:郵件頭Delivered-To部分

//rpline:郵件頭返回路徑

//無需"From "頭部

if (substdio_put(&ssout,rpline.s,rpline.len) == -1) goto fail;

if (substdio_put(&ssout,dtline.s,dtline.len) == -1) goto fail;

//將郵件寫到檔案fd中

switch(substdio_copy(&ssout,&ss))

{

case -2: tryunlinktmp(); _exit(4);

case -3: goto fail;

}

if (substdio_flush(&ssout) == -1) goto fail;

//將fd所指檔案資料由系統緩衝區寫回磁碟正確返回0，錯誤返回-1

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 */

//maildir 格式郵箱的郵件投遞，不要鎖定

void maildir(fn)

char *fn;

{

int child;

int wstat;

//#define seek_begin(fd) (seek_set((fd),(seek_pos) 0))

//指向檔案0的開頭

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

switch(child = fork())

{

case -1:

temp_fork();

case 0:

maildir_child(fn);/////////////////////////////////////

_exit(111);

}

//返回子程式fd的結束狀態值於wstat中

wait_pid(&wstat,child);

//#define wait_crashed(w) ((w) & 127)

if (wait_crashed(wstat))

temp_childcrashed();

//#define wait_exitcode(w) ((w) >> 8)

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)");

}

//mbox 格式郵箱的郵件投遞，必須鎖定

void mailfile(fn)

char *fn;

{

int fd;

substdio ss;

substdio ssout;

int match;

seek_pos pos;

int flaglocked;

//到檔案0開頭

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

//開啟檔案fn

fd = open_append(fn);

if (fd == -1)

strerr_die5x(111,"Unable to open ",fn,": ",error_str(errno),". (#4.2.1)");

//時間訊號，30秒

sig_alarmcatch(temp_slowlock);

alarm(30);

//鎖定

flaglocked = (lock_ex(fd) != -1);

alarm(0);

sig_alarmdefault();

//結尾

seek_end(fd);

//pos實際指向檔案尾（檔案大小）

pos = seek_cur(fd);

substdio_fdbuf(&ss,read,0,buf,sizeof(buf));

substdio_fdbuf(&ssout,write,fd,outbuf,sizeof(outbuf));

//dtline:郵件頭Delivered-To部分

//rpline:郵件頭返回路徑

//ufline:mbox 是標準的UNIX郵箱格式, 多個郵件存放在一個獨立檔案內, 每個郵件由一個"From" 的行開始.

//這一行看起來像一個標題欄位, 不過那不是標題, 那僅僅是傳送代理新增的, 便於郵件讀出器可以找到每個郵件開始部分的一個標記.

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 (;;)

{//讀一行

if (getln(&ss,&messline,&match,' ') != 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," ")) goto writeerrs;

break;

}

if (substdio_bputs(&ssout," ")) goto writeerrs;

if (substdio_flush(&ssout)) goto writeerrs;

//由緩衝區寫回磁碟

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;

//轉發郵件，地址在recips中

void mailforward(recips)

char **recips;

{//struct qmail {

// int flagerr;

// unsigned long pid;

// int fdm;

// int fde;

// substdio ss;

// char buf[1024];

// } ;

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,' ') != 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;

//#define seek_begin(fd) (seek_set((fd),(seek_pos) 0))

//typedef unsigned long seek_pos

//將檔案0的指標移到開始位置。

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

//給ss附值，ss->x=buf,s->fd = 0;s->op = read;s->p = 0(位元組數);s->n = sizeof(buf)(還有的空間)

substdio_fdbuf(&ss,read,0,buf,sizeof(buf));

for (;;)

{

if (getln(&ss,&messline,&match,' ') != 0) temp_read();

if (!match) break;

//判斷檔案是否結束

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);

}

//得到檔案".qmail"+dash+safeext+dashowner的許可權，正確返回0，錯誤為-1

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;

}

//qme檔案存在且是一般檔案返回1，否則為0

int qmeexists(fd,cutable)

int *fd;

int *cutable;

{

struct stat st;

if (!stralloc_0(&qme)) temp_nomem();

*fd = open_read(qme.s);

if (*fd == -1) {

if (error_temp(errno)) temp_qmail(qme.s);

if (errno == error_perm) temp_qmail(qme.s);

if (errno == error_acces) temp_qmail(qme.s);

return 0;

}

if (fstat(*fd,&st) == -1) temp_qmail(qme.s);

//S_IFREG表示一般檔案

if ((st.st_mode & S_IFMT) == S_IFREG) {

if (st.st_mode & auto_patrn)

strerr_die1x(111,"Uh-oh: .qmail file is writable. (#4.7.0)");

*cutable = !!(st.st_mode & 0100);//看檔案的owner許可權是否為可執行的。是*cutable = 1，不是*cutable = 0

return 1;

}

close(*fd);

return 0;

}

/* "" "": "" */

/* "-/" "": "-/" "-/default" */

/* "-/" "a": "-/a" "-/default" */

/* "-/" "a-": "-/a-" "-/a-default" "-/default" */

/* "-/" "a-b": "-/a-b" "-/a-default" "-/default" */

/* "-/" "a-b-": "-/a-b-" "-/a-b-default" "-/a-default" "-/default" */

/* "-/" "a-b-c": "-/a-b-c" "-/a-b-default" "-/a-default" "-/default" */

//開啟檔案&qme，如是一般檔案再看是否為default,如果是，"DEFAULT"+*(ext+i)結合加入

void qmesearch(fd,cutable)

int *fd;

int *cutable;

{

int i;

if (!stralloc_copys(&qme,".qmail")) temp_nomem();

if (!stralloc_cats(&qme,dash)) temp_nomem();

if (!stralloc_cat(&qme,&safeext)) temp_nomem();

if (qmeexists(fd,cutable)) {

if (safeext.len >= 7) {

i = safeext.len - 7;

if (!byte_diff("default",7,safeext.s + i))

if (i <= str_len(ext)) /* paranoia */

if (!env_put2("DEFAULT",ext + i)) temp_nomem();

}

return;

}

for (i = safeext.len;i >= 0;--i)

if (!i || (safeext.s[i - 1] == '-')) {

if (!stralloc_copys(&qme,".qmail")) temp_nomem();

if (!stralloc_cats(&qme,dash)) temp_nomem();

if (!stralloc_catb(&qme,safeext.s,i)) temp_nomem();

if (!stralloc_cats(&qme,"default")) temp_nomem();

if (qmeexists(fd,cutable)) {

if (i <= str_len(ext)) /* paranoia */

if (!env_put2("DEFAULT",ext + i)) temp_nomem();

return;

}

*fd = -1;

}

unsigned long count_file = 0;

unsigned long count_forward = 0;

unsigned long count_program = 0;

char count_buf[FMT_ULONG];

void count_print()

{

substdio_puts(subfdoutsmall,"did ");

substdio_put(subfdoutsmall,count_buf,fmt_ulong(count_buf,count_file));

substdio_puts(subfdoutsmall,"+");

substdio_put(subfdoutsmall,count_buf,fmt_ulong(count_buf,count_forward));

substdio_puts(subfdoutsmall,"+");

substdio_put(subfdoutsmall,count_buf,fmt_ulong(count_buf,count_program));

substdio_puts(subfdoutsmall," ");

if (mailforward_qp)

{

substdio_puts(subfdoutsmall,"qp ");

substdio_put(subfdoutsmall,count_buf,fmt_ulong(count_buf,mailforward_qp));

substdio_puts(subfdoutsmall," ");

}

substdio_flush(subfdoutsmall);

}

void sayit(type,cmd,len)

char *type;

char *cmd;

int len;

{

substdio_puts(subfdoutsmall,type);

substdio_put(subfdoutsmall,cmd,len);

substdio_putsflush(subfdoutsmall," ");

}

void main(argc,argv)

int argc;

char **argv;

{

int opt;

int i;

int j;

int k;

int fd;

int numforward;

char **recips;

datetime_sec starttime;

int flagforwardonly;

char *x;

umask(077);//將系統umask值設為077&0777的值。open函式的真正許可權為mode&-umask

sig_pipeignore();//忽略訊號

//將environ空間擴大（加10個字串位置）錯誤返回0

if (!env_init()) temp_nomem();

//-n Instead of reading and delivering the message, print a description of

// the delivery instructions. (man page)

//-N 是預設值

flagdoit = 1;

while ((opt = getopt(argc,argv,"nN")) != opteof)

switch(opt)

{

case 'n': flagdoit = 0; break;

case 'N': flagdoit = 1; break;

default:

usage();

}

argc -= optind;

argv += optind;

//將引數拷到相應的變數中。

if (!(user = *argv++)) usage();

if (!(homedir = *argv++)) usage();

if (!(local = *argv++)) usage();

if (!(dash = *argv++)) usage();

if (!(ext = *argv++)) usage();

if (!(host = *argv++)) usage();

if (!(sender = *argv++)) usage();

if (!(aliasempty = *argv++)) usage();

if (*argv) usage();

//目錄是以'/'開頭的

if (homedir[0] != '/') usage();

if (chdir(homedir) == -1)

strerr_die5x(111,"Unable to switch to ",homedir,": ",error_str(errno),". (#4.3.0)");

checkhome();

//將"HOST"和host結合為"HOST="+host，加到environ後面。下同

if (!env_put2("HOST",host)) temp_nomem();//接收地址的域名部分

if (!env_put2("HOME",homedir)) temp_nomem();//使用者的主目錄

if (!env_put2("USER",user)) temp_nomem();//當前的使用者

if (!env_put2("LOCAL",local)) temp_nomem();//接收地址的local部分

//將本地的地址擴充套件。如local為"dingwenbin",host為pact518.hit.edu.cn,則envrecip為"dingwenbin@pact518.hit.edu.cn"

if (!stralloc_copys(&envrecip,local)) temp_nomem();

if (!stralloc_cats(&envrecip,"@")) temp_nomem();

if (!stralloc_cats(&envrecip,host)) temp_nomem();

//將envrecip->s加'Z'拷到foo->s.

if (!stralloc_copy(&foo,&envrecip)) temp_nomem();

//#define stralloc_0(sa) stralloc_append(sa,"")

//GEN_ALLOC_append(stralloc,char,s,len,a,i,n,x,30,stralloc_readyplus,stralloc_append)

//struct stralloc{char *s;int len;int a;},len是s的長度，a是總共分配的空間。

//stralloc_ready(x,n)作用是：x沒有分配空間就分配n大小空間。已分配了且空間小於n就擴大空間

//stralloc_readyplus(x,n)作用是：x沒有分配空間就分配n大小空間。分配給x的空間小於x->len+n,就擴大空間

if (!stralloc_0(&foo)) temp_nomem();

//將"RECIPIENT"和foo.s結合為"RECIPIENT="+foo.s，加到environ後面。下同

//信封上接收者的地址

if (!env_put2("RECIPIENT",foo.s)) temp_nomem();

//郵件頭Delivered-To部分

if (!stralloc_copys(&dtline,"Delivered-To: ")) temp_nomem();

if (!stralloc_cat(&dtline,&envrecip)) temp_nomem();

for (i = 0;i < dtline.len;++i) if (dtline.s[i] == ' ') dtline.s[i] = '_';

if (!stralloc_cats(&dtline," ")) temp_nomem();

if (!stralloc_copy(&foo,&dtline)) temp_nomem();

if (!stralloc_0(&foo)) temp_nomem();

if (!env_put2("DTLINE",foo.s)) temp_nomem();

if (flagdoit)

bouncexf();

//將"SENDER"和sender結合為"SENDER="+sender，加到environ後面。

// 信封上傳送者地址

if (!env_put2("SENDER",sender)) temp_nomem();

//將"RPLINE"和"Return-Path: "結合後加入environ

if (!quote2(&foo,sender)) temp_nomem();

if (!stralloc_copys(&rpline,"Return-Path: if (!stralloc_cat(&rpline,&foo)) temp_nomem();

for (i = 0;i < rpline.len;++i) if (rpline.s[i] == ' ') rpline.s[i] = '_';

if (!stralloc_cats(&rpline,"> ")) temp_nomem();

if (!stralloc_copy(&foo,&rpline)) temp_nomem();

if (!stralloc_0(&foo)) temp_nomem();

//郵件頭返回路徑

if (!env_put2("RPLINE",foo.s)) temp_nomem();

//將"From"+*sender拷到ufline中。*sender為空，則將"From"+"MAILER-DAEMON"拷進去

if (!stralloc_copys(&ufline,"From ")) temp_nomem();

if (*sender)

{

int len; int i; char ch;

len = str_len(sender);

if (!stralloc_readyplus(&ufline,len)) temp_nomem();

for (i = 0;i < len;++i)

{

ch = sender[i];

if ((ch == ' ') || (ch == ' ') || (ch == ' ')) ch = '-';

ufline.s[ufline.len + i] = ch;

}

ufline.len += len;

}

else

if (!stralloc_cats(&ufline,"MAILER-DAEMON")) temp_nomem();

if (!stralloc_cats(&ufline," ")) temp_nomem();

//在ufline後面加上現在時間。

starttime = now();

if (!stralloc_cats(&ufline,myctime(starttime))) temp_nomem();

if (!stralloc_copy(&foo,&ufline)) temp_nomem();

if (!stralloc_0(&foo)) temp_nomem();

//UUCP風格的"From"行它包含訊息所參與的UUCP大宗

//路徑形式的路由、最後一臺接收訊息的機器處理訊息的時間和日期以及一

//指明從哪臺主機接收來的可選部分。由於每個處理過這個訊息的系統都會生成這個欄位，所

//以它通常包括在信封資料下。

if (!env_put2("UFLINE",foo.s)) temp_nomem();

//到空行的作用是：如果ext為"aa-bb-cc-dd",則依次把"EXT=aa-bb-cc-dd"，"EXT2=bb-cc-dd","EXT3=cc-dd","EXT4=dd"加入

//地址擴充套件

x = ext;

if (!env_put2("EXT",x)) temp_nomem();

x += str_chr(x,'-'); if (*x) ++x;

if (!env_put2("EXT2",x)) temp_nomem();

x += str_chr(x,'-'); if (*x) ++x;

if (!env_put2("EXT3",x)) temp_nomem();

x += str_chr(x,'-'); if (*x) ++x;

if (!env_put2("EXT4",x)) temp_nomem();

if (!stralloc_copys(&safeext,ext)) temp_nomem();

//將safeext中字串轉化為小寫的

case_lowerb(safeext.s,safeext.len);

for (i = 0;i < safeext.len;++i)

if (safeext.s[i] == '.')

safeext.s[i] = ':';

//例如host為202.18.236.150,則"HOST2=202.18.236","HOST3=202.18","HOST4=202",加入其中

//接收地址的域名部分

i = str_len(host);

i = byte_rchr(host,i,'.');

if (!stralloc_copyb(&foo,host,i)) temp_nomem();

if (!stralloc_0(&foo)) temp_nomem();

if (!env_put2("HOST2",foo.s)) temp_nomem();

i = byte_rchr(host,i,'.');

if (!stralloc_copyb(&foo,host,i)) temp_nomem();

if (!stralloc_0(&foo)) temp_nomem();

if (!env_put2("HOST3",foo.s)) temp_nomem();

i = byte_rchr(host,i,'.');

if (!stralloc_copyb(&foo,host,i)) temp_nomem();

if (!stralloc_0(&foo)) temp_nomem();

if (!env_put2("HOST4",foo.s)) temp_nomem();

flagforwardonly = 0;

qmesearch(&fd,&flagforwardonly);

if (fd == -1)/*檔案沒開啟*/

if (*dash)

strerr_die1x(100,"Sorry, no mailbox here by that name. (#5.1.1)");

if (!stralloc_copys(&ueo,sender)) temp_nomem();

if (str_diff(sender,""))/*sender不空*/

if (str_diff(sender,"#@[]"))/*sender和"#@[]"不同*/

if (qmeox("-owner") == 0)

{

if (qmeox("-owner-default") == 0)

{

if (!stralloc_copys(&ueo,local)) temp_nomem();

if (!stralloc_cats(&ueo,"-owner-@")) temp_nomem();

if (!stralloc_cats(&ueo,host)) temp_nomem();

if (!stralloc_cats(&ueo,"-@[]")) temp_nomem();

}/*ueo為local+"-owner-@"+host+"-@[]"*/

else

{

if (!stralloc_copys(&ueo,local)) temp_nomem();

if (!stralloc_cats(&ueo,"-owner@")) temp_nomem();

if (!stralloc_cats(&ueo,host)) temp_nomem();

}/*ueo為local+"-owner@"+host*/

}

if (!stralloc_0(&ueo)) temp_nomem();

//轉發的傳送人地址

if (!env_put2("NEWSENDER",ueo.s)) temp_nomem();

if (!stralloc_ready(&cmds,0)) temp_nomem();

cmds.len = 0;

if (fd != -1)

if (slurpclose(fd,&cmds,256) == -1) temp_nomem();

if (!cmds.len)/*如果fd檔案中沒有內容*/

{

if (!stralloc_copys(&cmds,aliasempty)) temp_nomem();

flagforwardonly = 0;

}

if (!cmds.len || (cmds.s[cmds.len - 1] != ' '))

if (!stralloc_cats(&cmds," ")) temp_nomem();

numforward = 0;/*檢查有幾行的第一個字元不是'#','.','/','|'*/

i = 0;/*i為每行的開始位置*/

for (j = 0;j < cmds.len;++j)

if (cmds.s[j] == ' ')

{

switch(cmds.s[i]) { case '#': case '.': case '/': case '|': break;

default: ++numforward; }

i = j + 1;

}

recips = (char **) alloc((numforward + 1) * sizeof(char *));

if (!recips) temp_nomem();

numforward = 0;

flag99 = 0;

i = 0;

for (j = 0;j < cmds.len;++j)

if (cmds.s[j] == ' ')

{

cmds.s[j] = 0;

k = j;

while ((k > i) && (cmds.s[k - 1] == ' ') || (cmds.s[k - 1] == ' '))

cmds.s[--k] = 0;

// 字元傳送型別值

// # 無 (註釋) 忽略

// | 程式由shell 執行的命令

// / 或者 . mbox郵箱格式 (如果路徑最後一個字元不是一個斜槓) mbox 的路徑名 (包括斜槓"/"或者點".")

// / 或者 . maildir郵箱格式 (如果路徑最後一個字元是一個反斜槓) maildir 的路徑名 (包括斜槓"/"或者點".")

// & 轉發轉發郵件的地址

// 字母或者數字轉發轉發郵件的地址 (包括第一個字元)

switch(cmds.s[i])

{

case 0: /* k == i */

if (i) break;

strerr_die1x(111,"Uh-oh: first line of .qmail file is blank. (#4.2.1)");

case '#':

break;

case '.':

case '/':

++count_file;

if (flagforwardonly) strerr_die1x(111,"Uh-oh: .qmail has file delivery but has x bit set. (#4.7.0)");

if (cmds.s[k - 1] == '/')

if (flagdoit) maildir(cmds.s + i);///////////////////////////////////////////

else sayit("maildir ",cmds.s + i,k - i);

else

if (flagdoit) mailfile(cmds.s + i);

else sayit("mbox ",cmds.s + i,k - i);

break;

case '|':

++count_program;

if (flagforwardonly) strerr_die1x(111,"Uh-oh: .qmail has prog delivery but has x bit set. (#4.7.0)");

if (flagdoit) mailprogram(cmds.s + i + 1);

else sayit("program ",cmds.s + i + 1,k - i - 1);

break;

case '+':

if (str_equal(cmds.s + i + 1,"list"))

flagforwardonly = 1;

break;

case '&':

++i;

default:

++count_forward;

if (flagdoit) recips[numforward++] = cmds.s + i;

else sayit("forward ",cmds.s + i,k - i);

break;

}

i = j + 1;

if (flag99) break;

}

//轉發的地址數不為0就轉發

if (numforward) if (flagdoit)

{

recips[numforward] = 0;

mailforward(recips);

}

count_print();

_exit(0);

qmail-local程式碼分析(轉)

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