我的子进程如何退出才正确？？(页 1) - C/C++ (STL/boost) - Linux伊甸园论坛

nils 发表于 2007-6-11 16:23

我的子进程如何退出才正确？？

小弟编写了一个TCP的服务器客户端相互发送信息的程序，代码如下。程序可以运行的，可是现在的问题是：我fork出的子进程没有正确退出？？
环境如下：现运行./server 然后运行./client，在client运行期间用ps -ef | grep server 观看进程信息，有2个进程，等到程序结束后再用同样的命令看，有一个变成了僵尸？？但是你再运行一次client的时候僵尸不见了，还是2个进程，为什么？那个不是僵尸？？&J!b5Q AC_/D
nils@linux-scj:~> ps -ef | grep server //第一次运行时的结果4s3J[(RQ*Pv1H%o
nils    19325 18236  0 16:14 pts/2 00:00:00 ./server
nils    19327 19325  0 16:14 pts/2 00:00:00 ./server
nils    19329 18761  0 16:14 pts/4 00:00:00 grep serverJ stmi*T2h
nils@linux-scj:~> ps -ef | grep server          //运行结束后的结果
nils    19325 18236  0 16:14 pts/2 00:00:00 ./servern}$x:A(G6_~w
nils    19327 19325  0 16:14 pts/2 00:00:00 [server] <defunct>#sM1a9wt.t#J
nils    19335 18761  0 16:14 pts/4 00:00:00 grep server]DD%Ilrc)s;B/{
nils@linux-scj:~> ps -ef | grep server       M5W8|6f#w{2V#w7d dT
nils    19325 18236  0 16:14 pts/2 00:00:00 ./serverI7bjQB-b$F
nils    19360 19325  0 16:17 pts/2 00:00:00 ./server
nils    19362 18761  0 16:17 pts/4 00:00:00 grep servery-])]G,ug7B9~d

不知道问题出在哪里，求助！
[code]
/*}H-IK+KOa-C
server.c  要求实现的功能：L|5QeVL"j
*/"\qiH/|1iGf
j@ t^1WE"g3[H
#include <stdio.h>
#include <stdlib.h>h&T.~s9q9_e%J)r
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>`y/M-J[[/Wa{Y
#include <netdb.h>
#include <string.h>
#include <netinet/in.h>
#include <sys/socket.h>3S^6@:JqT
#include <sys/wait.h>8cO,]UE#h

#define PORT 4444
#define BACKLOG 10 ])w*G ]2LA
#define MAXDATASIZE 4096
N.v Rn4m7`M.sg
int main()CZ(xSr2Q
{fLYQ+l:o&Dt2~
int listen_fd,new_fd;c+|8BK)z(K#m
fd_set readfds,writefds;
int ret;
char buf[MAXDATASIZE];
int sin_size;[hT MG7To
int numbytes;
struct sockaddr_in their_addr;
struct sockaddr_in my_addr;z v:lC$@[NT4p j

FD_ZERO(&readfds);
FD_ZERO(&writefds);

if ((listen_fd = socket(AF_INET,SOCK_STREAM,0)) == -1)
{
perror("socket");vs[ox[
exit(1);rNOg:\0F@0M
}

my_addr.sin_family = AF_INET;{hp ztPY1o
my_addr.sin_port = htons(PORT);
my_addr.sin_addr.s_addr = INADDR_ANY;
bzero(&(my_addr.sin_zero),8);
$X)[tR8Q4tXE hx)a
if(bind(listen_fd,(struct sockaddr*)&my_addr,sizeof(struct sockaddr)) == -1)
{G/Qg'u&v9p
perror("bind");7Q`:L"c*nqvP9?
exit(1);
}
9N8r4FoT4Nm/xt2Y;y|"r
if (listen(listen_fd,BACKLOG) == -1)+KHqp]Xq5@VfM
{"z IfiS6u}
f1[ k}z
}8T!RB)_m6F
+c+R@w-gT,m7b;{5fZ
FD_SET(listen_fd,&readfds);
for(;;)
{
ret = select(listen_fd+1,&readfds,NULL,NULL,NULL);S[R|4q8uF o
if(FD_ISSET(listen_fd,&readfds))s*B+OV/O$eF_
{
sin_size =sizeof(struct sockaddr_in);
if((new_fd = accept(listen_fd,(struct sockaddr*)&their_addr,&sin_size)) == -1)
{`dB}X fN3x'lytA
perror("accept");
continue;
}
printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr));[h\?Z+d:S2I

if (!fork())}/G|VS2u-I
{
//先发送一个信息给客户端]"N:Ul)E
if(send(new_fd,"Hello world\n",14,0) == -1)
{
perror("send");
close(new_fd);
exit(0);//这里在子进程里不能用continue;
}2J:QQN0wJ"_diB
FD_SET(new_fd,&readfds);
//FD_SET(new_fd,&writefds);
for(;;)
{
ret = select((listen_fd>new_fd?listen_fd+1:new_fd+1),&readfds,NULL,NULL,NULL);f P{\a]B
if(FD_ISSET(new_fd,&readfds)) \6V3n'eW.gq'or
{
if((numbytes=recv(new_fd,buf,MAXDATASIZE,0)) == -1)"Z uBoP"K
{
perror("send");
close(new_fd);Xy a\+PZ5q'o's'U&b
exit(0);//这里在子进程里不能用continue; u+J1AF,\
}
if (numbytes > 0)
{'L x`(I+gj0V
buf[numbytes] = '\0';z/~C!Z}P/F
printf("Recv: %d\t%s",numbytes,buf);"R*eM ZpJ:}V.l
}s g d,ZKx`
5MQ3I-@7@
Wa1w(i:_K,H
//这里可以使用一个特定的消息作为结束
if (strcmp(buf,"quit\n") == 0)
{,P@)~:W6pbh.o
printf("QUIT recved!\n");
FD_CLR(new_fd,&readfds);
close(new_fd);/e.W{V'F2M.}(PB Q
//exit(0); 这里如果用exit那么就会产生僵尸???
return 0;
//break;
}
//再向客户端发送一条信息-P-L$`vMcqD T
if (send(new_fd,"A new string\n",14,0) == -1)`.d#jkq'R!K
{f*`5Hvdg;V
perror("send");;FK5ok7?*WGd
close(new_fd);
exit(0);//这里在子进程里不能用continuex:}iQ r{At e;da
}7H7X*nH|uA0T
else
printf("Msg Send!\n");
} 5~C"z5Z2iR)kS
} L7J4UTH P6_-f!\1F
}
}1|)e|#bZ:Yf \
//等待所有子进程退出
while(waitpid(-1,NULL,WNOHANG)>0);
printf("Father Flushed!\n");
//return 0;5IY1Qp$l3ioB
}
return 0;W4n&GG"ukTR
}8d3R9G/h*])y

/*7H*YtR4X
client.c  要求实现的功能：每秒向server发送一个消息1t1T3{hWJh
*/)fyj3G~a

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>@Ve,}9K]h*GR+I
#include <sys/types.h>V$m7AUek;C
#include <unistd.h>
#include <errno.h>6zq _4`CofZ/A
#include <netdb.h>~q|;@ptZn2d.Q^l'p
#include <string.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>:O$@sW!X
:@*^4Jo!g&G%{+SN
#define PORT 44442oz?!w Z6j2k v
#define BACKLOG 10
#define MAXDATASIZE 4096/}Y1Y'vC
K/CKn Z1tJ
int main()
{F0Y$]5t~
int sock_fd,numbytes;
char buf[MAXDATASIZE];)z|*[xjR5^#_7o
struct hostent *he;
struct sockaddr_in their_addr;
int ret;
fd_set  readfds;
int cnt = 0;/@iCOF
char* strIP="20.0.0.5";*P8^C)t"xbdHC

FD_ZERO(&readfds);

if ((he = gethostbyname(strIP)) == NULL)
{(EEmC+}!_%X
perror("gethostbyname"); ~ECH%s Jh0u
exit(1);
}j1vho3X4stY

if ((sock_fd=socket(AF_INET,SOCK_STREAM,0)) == -1)
{
perror("socket");
exit(1);
}

their_addr.sin_family =AF_INET;
their_addr.sin_port =htons(PORT);!O}|qa XL9aS1G
their_addr.sin_addr = *((struct in_addr*)he->h_addr);d${#^8bn2{xQa
bzero(&(their_addr.sin_zero),8); {,hoQT#P5Q7e

if (connect(sock_fd,(struct sockaddr*)&their_addr,sizeof(struct sockaddr)) == -1)
{
perror("connect");
exit(1);3f@db2y'?
}

if ((numbytes = recv(sock_fd,buf,MAXDATASIZE,0)) == -1)3R7F!Ag?/FZ[
{
perror("recv");
exit(1); Z*cthb%v;z0}
}[vE+z"Cm0WI!d
if(numbytes > 0)#y']2cjD!L&i;b
{_,Qt4He-B.{ r1\^8a
buf[numbytes] = '\0';2gj+?Y%Mz |W3ip
printf("Recv:%s",buf);fAJi w:Z~J
}

while(cnt++ < 10)fG/TI9k|
{\%LjL.pHGG k eU,t
sleep(1);
if(send(sock_fd,"subsentence\n",13,0) == -1)\Hu6i!z
{
perror("send");!Ct s3U.@
close(sock_fd);Q8f3x:_L$B!MD
exit(0);//这里在子进程里不能用continue; c&~RS \ Iv
}-[kq?^2e?bi[
FD_SET(sock_fd,&readfds);
ret = select(sock_fd+1,&readfds,NULL,NULL,NULL);{2hAV9Mln;oH
if(FD_ISSET(sock_fd,&readfds))8Q)r8o*v{:E
{
if ((numbytes = recv(sock_fd,buf,MAXDATASIZE,0)) == -1)%}*Vx;n*Q ^Z qR!T
{$ih5Cyz\L q e
perror("recv");
exit(1); ?;yD'OBl|R
}+F;I,P im ^{y#]
if(numbytes > 0)
{,ld k8WD}|AE&NS
buf[numbytes] = '\0';^3r6SK/qB
printf("Recv:%s",buf);
}!lnolQ3]
}:_!skn'qF E
}

if(send(sock_fd,"quit\n",5,0) == -1)QJ4[YJ_qO$P)[
{
perror("send");2q(c-Zf1z{)hx
close(sock_fd);5|!x T(oZN
exit(0);//这里在子进程里不能用continue; &JhB W8A_,Pyc
}
close(sock_fd);&w8y:Nh,a
upbL(h
return 0;
}H_SiT!Z6O;|
8Fj)RE'Q0ehs^x
z8rf%m2]h-R
[/code]

flag 发表于 2007-6-12 11:54

//等待所有子进程退出
            while(waitpid(-1,NULL,WNOHANG)>0);
            printf("Father Flushed!\n");
man过waitpid吗？3]N{gD&C
WNOHANGTk(dX;uK9]
            which means to return immediately if no child has exited.

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我的子进程如何退出才正确？？